Aquaculture Scoop is a magazine for aquaculture professionals worldwide
Issue 11 / March 2016 Advanced Extrusion
Growth Promotion
For superior Fish Feed
The best solution
Processing Technology
Issues in Extrusion
Aquafeed Innovation
Gordon Young / Dennis Forte
Expo list
The world’s top events related to milling from around the world, listed on p. 31
Innovation in Aquafeed
14/17 Offshore/Onshore Risks in aquaculture
Clextral’s new systems deliver improved flexibility and control, plus energy savings
PAGE 20
Read more on p.6
FILTRATION OF COLLOIDAL MATTER
In Recirculating Aquaculture Systems Read more on page 19 Published by Nisa Media Ltd www.aquaculturedirectory.co.uk www.facebook.com/nisamedia www.twitter.com/Aquaculturedire
Aerators in ponds
p.25
Advanced Extrusion
p.2
Editorial
Issue 11 / March 2016 Advanced Extrusion
Welcome to the latest issue of Aquaculture Scoop. In this issue we take a look at Extrusion advances with insight from Andritz, Gordon Young and Dennis Forte. We learn about Processing Technology in Aquafeed production, growth promotion solutions and worms in wastewater management. We also have an Article from Willis Towers Watson on Insurance in Aquaculture with Onshore and Offshore perils. As you will see this is a packed out issue, the news of a major breakthrough in Ammonia/Nitrite control from Bio Industries of Ireland is worth a read too! As ever, please send us your comments and articles for inclusion, contact details below right.
www.aquaculturedirectory.co.uk
Keeping in touch with Aquaculture Scoop, follow us on: Twitter: www.twitter.com/Aquaculturedire Linkedin: www.linkedin.com/company/nisa-media-ltd Scoop it: www.scoop.it/t/aquaculture-directory Paper.li: www.paper.li/Aquaculturedire/1334242719 Pinterest: www.pinterest.com/aquadirectory/ Facebook: www.facebook.com/pages/Aquaculture-Directory/27260116281734
For superior Fish Feed
Processing Technology Aquafeed Innovation
Issues in Extrusion Gordon Young / Dennis Forte
Growth Promotion The best solution
Events
The world’s top events related to milling from around the world, listed on p. 31
>> Published by: NISA Media Ltd 14 Clarke Way Cheltenham GL50 4AX United Kingdom
www.aquaculturedirectory.co.uk > Editorial Manager Nicky Barnes Tel: +44 117 2306494 Email: nbarnes@aquaculturedirectory.co.uk > International Marketing Manager Sabby Major Tel: +44 117 2306493 Email: smajor@aquaculturedirectory.co.uk > News Editor Martin Little Email: mlittle@aquaculturedirectory.co.uk
Aquaculture Scoop / March Issue 2016
Page 1
The nutritional quality of fish feed can be defined as: • Recovery of essential amino acids and
Advanced extrusion technologies for superior fish feed characteristics
specific vitamins • Digestibility On most newer extruder designs, an optimum screw configuration can be established in order to apply the SME quantity necessary for matching a specific product (for example salmon or trout feed) with a high content of fat/oil, internal oil or similar products with high nutritional value. A screw configuration can be optimized to apply more SME by implementing the
> Back pressure valve (FLEXTEX ™) and Expansion Control System (ECS™) – Combining two unique process technologies for full feed controllability. Extruding fish feed is primarily a matter of
the extruder, it is possible (to a certain
following components:
extent) to supply the specific mechanical energy (SME) necessary to produce a given
• Screw design and geometry
product with an optimum degree of cook.
• Shear locks
The degree of cook is decided from both a
• Kneading blocks
nutritional as well as a physical product
• Reverse elements
quality point of view.
cooking the starch. The better starch cook,
An optimum screw configuration is not
the better feed quality. However, it is
The physical quality of fish feed product can
always capable of applying sufficient SME to
equally important to control the expansion
be defined by:
produce a given product. Often it is also
of the feed and thus influencing the density
necessary to optimize other parameters that
which determines the sinking and the
• Density
can be used to increase the SME supply in
floating properties.
• Shape and size
the extruder:
• Uniformity Screw configuration for optimum cook
• Durability
• Screw speed
By making a specific screw configuration on
• Water stability
• Open area of venturi die • Open area of die plate • Extruder capacity
> The ANDRITZ FLEXTEX system – reduced downtime and optimum production flexibility Changes in screw configuration and other
Picture 1: ANDRITZ extruder EX1021. Capacity: 2-12 tph
measures that contribute with either higher or lower SME values are all operations that usually result in down time and increased production costs. These changeover procedures can easily take up to 0.5 - 2 hours to adapt. Therefore, technological advances focusing on both cost savings in the form of reduced down time as well as optimal flexibility in terms of capacity and quality are in high demand by the aquaculture industry.
Aquaculture Scoop / March Issue 2016
Page 2
Picture 2: ANDRITZ extruder EX1250. Capacity: 10-12 tph.
> The FLEXTEX working principle
3000 mm2 to 100 mm2 (4.65 to 0.15 in2)
The mechanical design
depending on throughput. The FLEXTEX system is able to continuously
The FLEXTEX system consists of 3 parts:
control the SME applied in the extruder
With the FLEXTEX system, the extruder
1. The PLC control system
during operation without changing the
operator can determine how much specific
2. The venturi die and the piston system
extruder configuration or other parameters.
mechanical energy (SME) the product needs.
3. The hydraulic station
By changing only this one parameter, it will
From a control system, for example a separate
have the following advantages in the
control or alternatively a control integrated in
The FLEXTEX system is designed with focus
production of fish feed:
the extruder control, the operator can make a
on simplicity and consists of a few compo-
set-point for example kW/ton (HP/ton) dry
nents. However, the critical part of the
• The starch cook (up to 100%) is
matter. By means of a hydraulically controlled
system is the piston which, besides from
completely controlled during operation
piston, the FLEXTEX system automatically
being used as a restriction for the meal flow,
• The bulk density of the product can be
adjusts in relation to the set-point by
also distributes the meal to the die plate.
reduced by up to 30% and can be controlled
decreasing or increasing restriction of the
When restricting the meal flow, it is
with an accuracy of ±5 g/l (0.3 lbs/ft3)
venturi die by moving a piston.
essential that this takes place synchronically
• Higher addition of oil and less starch in the formula without significant influence to bulk density and product quality The system adjusts the opening area in the venturi die plate, which is placed between the last screw and the die plate in the extruder. The venturi die is used in many extruders in a stationary design to decrease or increase the kneading zone in the extruder in order to control the SME applied. This is done by adjusting the size of the hole and thus the opening area and the pressure against it. Smaller holes increase the pressure and thus more energy consumption from the main motor. With the FLEXTEX system the opening area of the venturi die can typically be adjusted from
Aquaculture Scoop / March Issue 2016
Figure 1: FLEXTEX in neutral position – no additional SME applied
Page 3
> Documented results from the FLEXTEX and ECS systems The FLEXTEX and the ECS systems can be installed individually or as a combined concept. This is simply a question of each producer’s requirements for their production. Documented tests supported by experience from systems in full scale operations have shown significant advantages when using the ANDRITZ FLEXTEX and ECS system. During a series of tests with a shrimp feed formula (70% protein), below tests were conducted.
Figure 2: FLEXTEX in closed position – additional SME applied.
Test A: FLEXTEX effect on starch cook By increasing the SME in the extrusion process by approximately 12%, the cook rate was increased by 11.8%. See Fig. 4 Test B: ECS effect on bulk density
in order not to hinder the flow ability.
knife house results in a reduction of
The ECS can increase the bulk density by
Changes in the meal flow will influence the
flash-off and thus an increase of bulk
25% by adjusting the pressure in the knife
visual quality of the product due to an
density (less expansion). Higher overpres-
house only. See Fig. 5
uneven pressure at the die plate. The piston
sure, higher density (less expansion).
in the FLEXTEX system is moved axially and at the same time it is conical, so that the meal flow is not negatively influenced.
The ANDRITZ Expansion Control System (ECS) – for increased bulk density
could be obtained as with original high starch formula, but without FLEXTEX (8
To be able to control the bulk density of
hours).
products in a wide range and at the same time obtain an optimum product quality, the
Insert: Figure 7
ANDRITZ Expansion Control System (ECS) is unique. The ECS concept is based on controlling the expansion in the extruder
Summary
knife house without influencing the product
The FLEXTEX and ECS system provides
quality. Thus all desirable parameters can
significant flexibility in the production of
be used in the extruder without regard to
feed for all fish species. By continuously
expansion. The main focus here is product
controlling the SME during operation, it is
quality.
possible to achieve an optimum physical quality. At the same by using the ECS to
By adding compressed air in the knife house, it is possible to control and adjust the pressure. This is made possible by mounting an airlock under the knife house (see figure 3). An increased pressure in the
Aquaculture Scoop / March Issue 2016
control the density, two unique tools for
Picture 3: Extruder with FLEXTEX installed.
controlling finish product characteristics are present. The advantages of the systems can be summarized into: •
Increase starch cook by 10-15%
Page 4
controlling the SME during operation, it is possible to achieve an optimum physical quality. At the same by using the ECS to control the density, two unique tools for controlling finish product characteristics are present. The advantages of the systems can be summarized into:
Figure 3: FLEXTEX and ECS
• Increase starch cook by 10-15% • Decrease bulk density by 20-30% • Increase bulk density by 0-5% • No change of screw configuration which means reduced down time • Only two parameters needed for control-
Test C: FLEXTEX effect on water stability
ling starch cook, reduced and increased bulk
By increasing the SME it was possible to
density
increase the water stability by additionally 6 hours. See Fig. 6
Figure 4
Figure 5
Figure 6
Figure 7
Test D: Reduced starch contents in formula by means of FLEXTEX By reducing the starch contents by approximately 50%, equal water stability (8 hours) could be obtained as with original high starch formula, but without FLEXTEX (8 hours). See Fig. 7
> Summary The FLEXTEX and ECS system provides significant flexibility in the production of feed for all fish species. By continuously
Picture 3: Extruder with FLEXTEX installed.
Aquaculture Scoop / March Issue 2016
Page 5
Innovation in aquafeed processing technology:
Clextral new Preconditioner + and twin screw extruder EVOLUM+
Clextral’s new systems deliver improved flexibility and control, plus energy savings More information: Mariel Badel Clextral Marketing Department www.clextral.com
World leading aquafeed technology expert,
the finished food products; it enables energy
ports have been optimally positioned to
Clextral has played a pioneering role in the
savings, while providing greater flexibility
enhance absorption and product exposure
innovation and development of twin screw
and reduced maintenance within the global
time during the mixing stage.
extrusion for aquafeed since the 70’s. To
extrusion process, whatever the recipe.
respond to new challenges and increase the
Extensive experimental trials have been
capacity of existing systems, Clextral is
The key innovation of Clextral’s Precondi-
carried out on the Preconditioner+ to verify
introducing major innovations in 2014: a
tioner that improves heat and mass transfer
the process improvements generated by its
combined twinshafts preconditioner and a
to the product is the Advanced Filling Control
AFC system on the twin-screw extrusion
new range of twin screw extruders with on
device (AFC); it interacts directly on the
process. In this case, a standard fish-feed
board advanced control system.
material inside the mixing chamber and
recipe (basic trout feed) was used, not to
enables the filling ratio to be adjusted. The
gauge optimal performance but to set an
AFC system uses an exclusive conveying
objective benchmark compared to traditional
screw inside the tank and adjusts the flow by
preconditioning systems.
New Preconditioner+: process flexibility and improved efficiency
a partial and controlled recycling of the material being processed, from the outlet to
In twin screw extrusion of fish-feed pellets,
the entry point, thus intensifying the specific
preconditioners are recognized by industry
preconditioning functions.
Increase of the filling ratio in the Preconditioner+ during fish feed trials
experts for their production benefits. The new Clextral Preconditioner+ integrates two horizontal, intermeshing, counter-rotating shafts that provide tangible production
Advanced Filling Control (AFC) system: key innovation of Clextral new preconditioning system
Aquaculture Scoop / March Issue 2016
lowering of the SME (Specific Mechanical Energy) required in the extruder mainly due to the increase of preconditioning time. As
benefits : improving the overall mixing and cooking process and therefore the quality of
The first significant observation was a
The adjustable water and steam injection
mentioned previously, this efficient
Page 6
pre-cooking reduces the shear and the
In terms of hygiene and food safety, the
gives processors new levels of throughput,
torque requirements in the extruder, which
Preconditioner+ is designed with minimal
flexibility, and control while ensuring
results in less wear of the screws and
retention areas to facilitate cleaning. This
maximum product quality and process
barrels.
feature is further enhanced by an integrated
stability.
“quick recipe change-over” function through By focusing exclusively on the
the reversible AFC system, used here as an
A major innovation, the Advanced Thermal
Preconditioner+, the experiment also
efficient emptying device. These two larges
Control (ATC) is a self-learning, proprietary
demonstrated that the new filling ratio (up
doors allow the quick access to the shafts
software solution to ensure absolute
to 75%) achieved with AFC made it possible
and screws for a perfect cleaning. Cleaning
precision in temperature control. ATC
to increase residence time by 60% for an
capabilities and hygienic design are
continuously monitors production and
equivalent fish feed flow and therefore to
important advantages for food processing
adjusts to changes in parameters
exceed the average of three minutes. At the
applications.
(characteristics of raw materials, recipes,
same time, the combination filling/steam
throughput, etc.) to ensure process and
distribution made it possible to achieve a
New range of twin screw extruders:
product consistency. ATC is proven to
product temperature between 85°C to 95°C.
EVOLUM+ sets a new standard
enhance process stability up to 70%, with
Following the improvements on the
Clextral’s new EVOLUM + twin-screw
energy savings averaging 20% by eliminating
pre-cooking stage, a significant increase in
extruders offer advanced technology that
excess heating/cooling to maintain process
starch gelatinization before product feed into the extruder was witnessed and measured. Finally, on the finished product after extrusion, granulation and drying, these upstream modifications resulted in increased hardness of the pellets between 10% up to 30% depending on process conditions. The strong mechanical design allows the system to start up when fully charged, even after prolonged down time with a full tank, thanks to the new kinematic feature.
Aquaculture Scoop / March Issue 2016
Page 7
Clextral continues to innovate with twin
accurately control pellet density for specific
screw extrusion systems that produce
product attributes, such as sinking and floating
aquatic feed with a precise balance of
properties. With these innovations in
proteins, oils and carbohydrates, processed
preconditioner and extruder technologies,
for optimum digestibility with reduced
Clextral is helping aquafeed processors meet
waste. Clextral’s systems process a wide
the process challenges of today and the future.
selection of recipes and raw materials and
> Improved response time and stability thanks to Advanced Thermal Control (ATC) proprietary innovation. The EVOLUM+ range has also been specifically built for more hygienic processing and food safety with ergonomic designs and open profiles that allow full machine access.
Aquaculture Scoop / March Issue 2016
Page 8
ISSUES IN EXTRUSION OF AQUAFEEDS Gordon Young, Food Industry Engineering, Australia Dennis Forte, Dennis Forte & Associates, Australia The authors are presenting short courses on “Aquafeed Extrusion Technology” and “Drying Technology” at Centre for Feed Technology, FôrTek, Norway, in May 2016. Also an Extrusion Course in Thailand in July 2016 (www.fie.com.au/events)
Introduction
the technology – the extrusion process
Firstly, realise that starch does not truly
needs to be properly understood. This
“gelatinise” during extrusion – there is not
Extrusion technology provides a number of
paper discusses just a couple of the issues
enough water present for the swelling and
major benefits over the more traditional
relating to successful extrusion of
unravelling of granules that characterise the
pellet milling processes commonly used for
aquafeeds.
gelatinisation reaction. In addition, the
aquaculture feeds. In particular extrusion can provide a much higher degree of control over the “cook” achieved, as well as better
starch is easily damaged by excessive
Extrusion chemistry & aquafeed ingredients
“shear” during extrusion. So we promote conditions that will “cook” the starch – achieving sufficient temperature with
control of the product density (therefore controlling the floating/sinking characteris-
In the area of ingredients, the aquafeeds
sufficient water, and with sufficient time,
tics).
industry faces a series of contradictions.
but without excessive shear – therefore use
Marine meals provide the best nutritional
of a preconditioner can be a major
But extrusion is a very complex process –
basis, but are increasingly difficult to obtain
advantage.
and we only have “indirect” control over that
and are therefore expensive. Selected plant
process. We never have just one parameter
sources of protein can provide required
Another option – if we require starch for
change during extrusion – if ingredients
proteins, but tend to come with fibre and
pellet binding – is to choose a starch that
vary, it doesn’t just change the final product
starch which can interfere with the
cooks and binds more effectively at a lower
composition – it changes the rheology of the
extrusion process and affect digestibility.
temperature – such as use of tuber starches
mix and therefore changes how the melt
We generally require very high fat (energy)
instead of grain starches. Therefore effective
moves through the extruder and the die,
contents in the feeds – but high fat levels
selection of both the source and the amount
which in turn affects the residence time and
are a problem in extrusion. Following are
of starch can be used to optimize the
temperature developed in the melt, which
some basics of “extrusion chemistry” that
processing and nutritional characteristics of
changes degree of cook and expansion –
relate to the way we design aquafeed
the product formulation.
and therefore affects digestibility and
extrusion processes:
floating/sinking characteristics. Within this complex relationship, we need to achieve
Protein Starch During extrusion, the protein denaturation
consistency – of nutrition, of digestibility, of physical characteristics. It is the cumulative
Many fish species do not tolerate starch –
reaction is not unlike that of starch – that is,
effect of these parameters which ultimately
especially uncooked starch. But starch
with respect to good “functional” protein
determine the feed conversion ratio (FCR)
comes with many of the alternative
(here referring to protein functionality from
for the product.
plant-based protein ingredients. Also starch
a physical, rather than nutritional, perspec-
can be an important “binder” to help
tive). The globular proteins unravel and,
achieve pellet durability.
under the right conditions (optimal
So to use extrusion effectively – and take full advantage of the opportunities offered by
Aquaculture Scoop / March Issue 2016
moisture content and temperature), can
Page 9
cross-link. Therefore “functional” protein contributes to binding and pellet durability. But many of the traditional fish meals, while good nutritionally, contain denatured protein, and contribute little to the “binding” function. So while the scarcity of traditional marine proteins (eg fish meals) is an issue for nutritional balance, the substitution of “functional” plant proteins can have the
Effect of Density on Sink / Float Pellet Behaviour
Sea Water (3% Salt)
Fresh Water
Fast Sinking
> 640 g/L
> 600 g/L
Slow Sinking
580 to 600 g/L
540 to 560 g/L
Neutral Buoyancy
520 to 540 g/L
480 to 520 g/L
Floating
< 480 g/L
< 440 g/L
added benefit of assisting pellet durability – as long as the process promotes rather than destroys that functionality (temperature and
Density control
shear not excessive).
Fat
The bulk density is the result of the balance between the expansion (influenced by the
The finished product bulk density is one of
process conditions and the amount and type
the key product quality attributes, directly
of starch) and elastic collapse (influenced by
affecting the sink/float behaviour of the
the amount and type of protein). That is, again
Fat under normal extrusion conditions is
finished product. Note, however, that this
there is a complexity in the extrusion process
stable – it does not itself change and “cook”
does not only relate to the extrusion
which makes it inherently difficult to predict
as starches and proteins do. But it does
process – drying also affects pellet density.
and control. Under the correct conditions:
have a major effect on the extrusion process
In fact, inappropriate drying can result in
– increasing “slip” and effectively lowering
drying and shrinkage of the outside layers,
• Higher amylose starch content makes the
viscosity, and therefore affecting
increasing overall density so the pellet sinks
extrudate puff more at the time of exiting
expansion/density, extruder backfill/degree
(perhaps as required). Then, over time in
the die
of cook, and pellet durability. An increase in
storage, moisture redistributes within the
• Higher “functional” protein makes the melt
fat content of the mix of only 2% (which can
pellet, the outside layers relax and expand,
more elastic, so it recoils after the initial puff
happen due to raw material variations) has
and the feed turns from floating to sinking.
and starts to collapse
a similar effect on the effective viscosity of the melt as a 5% increase in moisture content. Therefore control of fat content can be a major issue. At the same time, for most species, as high a fat content as possible is required for nutrition. This is where one of the tensions lie – the challenge of achieving good stable pellets at sufficiently high fat content. Strategies to achieve this balance include the use of appropriate extrusion systems (twin screw extruders can operate in a more stable manner to higher fat levels than single screw extruders), and methods to maximise post-process addition of oil, such as vacuum infusion. There are of course many other aspects of ingredients that also need to be balanced in successful feed extrusion.
Aquaculture Scoop / March Issue 2016
Page 10
Figure 1.
• Higher amylopectin starch increases the
Formulation + Process
Product
So the final pellet size – and therefore
The ingredient source (and the order of
Extrusion is not a simple process. The
density – is the result of the interaction of all
addition) have a significant impact upon the
interactions that occur in process param-
these effects. This is illustrated in Figure 1.
product nutrition. For example, the effect of
eters, along with variations in raw materials
Conclusion
oil added during the process is not the same
and changes over time due to extruder and
In addition:
as oil added via external coating –
die wear, makes it a difficult process to
Degree of Expansion = f { Melt Temperature
complexes formed during extrusion can
control. And these variations can have
(TM), Die Pressure Drop (ΔPd) },
change the nutritional effect of the oil.
“invisible” effects – because nutritional
with the Melt Rheology and the Die Geometry greatly affecting ΔPd.
content of the formulation does not fully Energy inputs also have a major role in final
define the nutritional performance of the
nutrition of the feed. Energy may be added
feed. Variations in the extrusion process do
The product bulk density is also significantly
via Convective Energy (steam injection),
not only affect physical changes in the
influenced by the Specific Mechanical
Thermal Energy (barrel heating) and
product such as density and size/shape, it
Energy (SME), since the SME directly affects
Mechanical Energy (viscous dissipation or
also affects the way in which the fish will
both temperature and molecular degrada-
SME). The comparative balance of these
digest the ingredients. A good understand-
tion of the starch and protein – which
energy inputs affect nutrition by changing
ing of the extrusion process is required for
changes the viscosity and elasticity of the
the conversion and break-down of proteins
reliable and consistent feed production.
melt. Figure 2 shows some measured results
and starches, changing their nutritional
of bulk density vs SME.
contribution. In extreme cases, it can even form fat complexes that are toxic to fish.
The SME is influenced by process parameters, most significantly the melt moisture content (used to manipulate the melt
Figure 2.
rheology), the screw profile design, and the screw speed.
Aquafeed specifications – not the full story Final product nutrition (and FCR) is not just due to the composition of the formulation ingredients – though that is what feed specifications almost exclusively (along with density) often dictate. The manufacture of a feed should be considered as:
Aquaculture Scoop / March Issue 2016
Page 11
The best solution for growth promotion in aquaculture Rui Gonçalves, Scientist - Aquaculture, Benedict Standen, Product Manager – Aquaculture, Gonçalo Santos, R&D Manager - Aquaculture
Case 1: Phytogenics to improve digestibility
The aquaculture industry is characterized by
factors, including genetic characteristics of
a large variety of species compared to other
the species, diet quality, environmental
methods of animal production. Conse-
conditions and absence of disease
quently, there is huge diversity in feeding
outbreaks. Add to this industry pressure,
The reliance on less costly protein sources
habits (carnivorous, omnivorous or
such as the need for the efficient use of
and low-nutrient diets to replace costly
herbivorous), physiology, rearing environ-
increasingly expensive raw materials or
fishmeal - whether for economic or
ments (marine, brackish, or freshwater
health management, and the picture
sustainable reasons - will most likely lead to
habitats) and temperature (cold,
becomes more complex. A focus on good
lower protein digestibility, higher amino
sub-tropical or tropical climates) and also in
gut health can help to successfully navigate
acid imbalance and higher carbohydrate
feed formulations. Identifying the correct
this large set of considerations and set the
and fiber content, since plant raw materials
tool to promote growth must take into
foundation for better growth.
are less digestible and negatively impact the
consideration each of these elements along with the value of the species and the specific
Identifying the right solution
challenge affecting the each production system.
Growth performance and gut health It is no secret that optimum animal performance encompasses a number of
gastrointestinal tract. The presence of undigested nitrogenous compounds in the intestine favors the formation of ammonia
Identifying the most promising strategy to
and biogenic amines by the intestinal
achieve the best growth performance can be
microbiota. These toxic compounds cause
a challenge. Here we provide three different
an imbalance of the intestinal microbiota,
scenarios on how to support gut health and
resulting in inflammatory processes and
growth enhancement using distinctly
accelerated turnover of the intestinal tissue,
different tools.
leading to poor performance. In addition, sub-optimal animal performance due to
Figure 1. Feed conversion ratio and specific growth rate of sea bream as affected by diet supplementation with Digestarom® P.E.P. MGE. Source: Biomin trials, 2012
Aquaculture Scoop / March Issue 2016
Page 12
inefficient nutrient use, results in increased feed usage and consequently higher production costs, environmental problems (higher ammonia emissions) and disease vulnerability. Phytogenic feed additives —consisting of herbs, spices, extracts or other plantderived compounds— have gained considerable attention as a tool to achieve improved growth performance. The active ingredients (e.g. phenols and flavonoids) can exert multiple effects in animals, Figure 2. Nutrient retention of sea bream as affected by supplementation with Digestarom® Source: Biomin trials, 2012
including improvement of feed conversion ratio (FCR), digestibility, growth rate, reduction of nitrogen excretion and improvement of the gut flora and health status. In the case of nutrient sparing or fish meal replacement, phytogenics can stimulate the digestive secretions, increase villi length and density and increase mucous production through an increase in the number of globlet cells. As a result, phytogenics can improve feed digestibility, especially for proteins and amino acids. In a trial with gilthead sea bream (Sparus aurata) at the University of Algarve in
Figure 3. Nitrogen budget (gain, fecal losses and metabolic losses) in sea bream with supplementation by Digestarom® Source: Biomin trials (2012)
Portugal, fish were fed a low fishmeal diet (14%), supplemented with a matrixencapsulated phytogenic feed additive (Digestarom® P.E.P.MGE). Dietary supplementation with Digestarom® P.E.P. MGE showed the best results with a significant reduction of FCR from 1.28 up to 1.12 and an improvement of specific growth rates (from 1.76 to 1.82 %.day-1) (Figure 1). Inclusion of the phytogenic products in the diet significantly enhanced (p < 0.05) protein and fat retention (Figure 2). The results also showed that a significant reduction of total nitrogenous losses, which was clearly associated with lower metabolic losses (Figure 3).
Case 2: Probiotics for pathogen control Figure 4. Feed conversion ratio of trout with diet supplementation using AquaStar® Hatchery Source: Biomin trials, 2010
Aquaculture Scoop / March Issue 2016
The use of beneficial bacteria (probiotics) to
Page 13
control pathogens is well documented in aquaculture, given the richness of microbial life in aquatic environments. Probiotic bacteria can maintain a healthy balance of bacteria in the gut through: competitive exclusion (beneficial bacteria exclude potential pathogenic bacteria through competition for attachment sites and nutrients); antagonism (inhibit the growth of pathogenic bacteria by producing, for example, bacitracin and polymyxin (produced by Bacillus spp.). Probiotics can also promote gut maturation and integrity, modulate and stimulate the immune Figure 5. Lactobacilli count in trout gut fed AquaStar速 Hatchery supplemented diets. Source: Biomin, 2010
system, prevent inflammation, boost the metabolism, increase digestive enzyme activity, decrease bacterial enzyme activity and ammonia production, improve feed intake and digestion, and neutralize enterotoxins. With this in mind, a total of 60 juvenile rainbow trout (Oncorhynchus mykiss) were used in a trial carried out at a commercial trout farm in Karditsa, Thessaly, Greece. Here we tested the effect of dietary incorporation of AquaStar速 Hatchery (multi-strain probiotic) on growth performance and intestinal bacteria count. Here we saw that probiotic, significantly (p < 0.05) increased body weight gain in the test group when compared to the control by an
Figure 6. Specific growth rate Pangasius catfish (Pangasionodon hypophtalmus) fed Biotronic速 supplemented diet or flavomycin, compared to control group. Source: Biomin, 2014
average of 10.8 %, FCR was significantly (p < 0.05) improved by 18.8 % (Figure 4) and Lactobacilli loads were 54.6 % higher in probiotic fed fish compared to fish fed the basal diet only (Figure 5). As their name suggests, lactic acid bacteria, including lactobacilli, produce vast quantities of lactic acid. This lowers the pH of the intestinal environment, which inhibits the growth of some harmful bacteria.
Case 3: Sustainable replacement for AGPs Unlike antibiotic growth promoters, which kill both beneficial and harmful bacteria, organic acids attack Gram-negative Figure 7. Total bacteria count in pangasius catfish gut (Pangasionodon hypophtalmus) fed Biotronic速 supplemented diet or flavomycin, compared to control group. Source: Biomin, 2014
Aquaculture Scoop / March Issue 2016
(pathogenic) bacteria while leaving the beneficial ones in place. In the undissoci-
Page 14
ated form, organic acids can freely diffuse
Biotronic® supplemented diet had an
to withstand infectious and non-infectious
through the semi-permeable membrane of
improvement of 1.72% in SGR compared to
stressors. Given the wide range of consid-
the bacteria into the cell cytoplasm. Once in
the control group and 0.86% when
erations in aquaculture production, a focus
the cell, where the pH is maintained near 7,
compared with the flavomycin group (Figure
on good gut health can help farmers to
the acid will dissociate and suppress
6). Analyzing the bacteria counts in the gut,
enhance growth. A number of novel feed
bacterial cell enzymes (e.g., decarboxylases
it was evident that animals fed Biotronic®
additives –such as probiotics, phytogenics
and catalases) and nutrient transport
supplemented diets had a considerable
and organic acids– can help support gut
systems. The reduction of pathogenic
reduction in total bacteria count, -76% than
health and growth enhancement. Further-
intestinal bacteria, which can produce toxin
the control group and -43% when compared
more, unlike antibiotics, these natural
causing damage of intestinal villi and crypt
with the flavomycin group (Figure 7).
solutions facilitate consumer perceptions of
structure, is directly associated with the improved gut structure. Furthermore, lower
bio-security and sustainability.
Conclusion
abundance of pathogens in the immediate environment allows the animal to direct
Understanding gut health requires the
more energy into somatic growth, as
elucidation of the complex interactions
opposed to fighting disease. In a trial at the
between many components that will allow
Aquaculture Centre of Applied Nutrition
the gut to perform under normal physiologi-
(ACAN) in Vietnam, Pangasius catfish fed the
cal conditions, thereby supporting its ability
Aquaculture Scoop / March Issue 2016
Page 15
Filtration of colloidal matter in Recirculating Aquaculture Systems (RAS)
More information: Julian A. Mamo Water Engineering, monitoring and control systems AquaBioTech Group Central Complex Naggar Street Targa Gap, Mosta MST 1761 Malta G.C. SKYPE: jam-abtg Main Office: +356 2258 4100 Mobile: +356 9996 7550 Direct Line: +356 2258 4114 Rob J. Davies Senior Aquaculture Consultant AquaBioTech Group Central Complex Naggar Street Targa Gap Mosta MST 1761 Malta G.C. SKYPE: rjd-abtg Main Office: +356 2258 4100 Mobile: +356 9910 2565 Direct Line: +356 2258 4119
Land-based recirculation systems are a
tive methods that are developed and tested
organic matter. The organic matter in
modern alternative to traditional net-pen
at our R&D facility in Malta and applied in
aquaculture water varies with the quality of
and flow through culture systems. They
the construction of our commercial scale
the incoming water, the production on the
offer a strict control and monitoring of the
RAS farms.
farm (species, feed, growth rate, etc.) and
environment that the organisms are grown
whether seawater or freshwater is used.
in, which is bio-secure and non-detrimental
A key component in operating intensive RAS
Colloidal organic compounds, to be
to the surrounding environment. Due to the
is controlling the accumulation of fine
removed, typically include microorganisms
extremely fast growth rates and efficient
particulate matter known as colloids. There
(bacteria, viruses, fungi and algae), faeces
utilization of precious water supplies,
is no strict range of particles that are
and waste feed, while dissolved organic
investment and development of RAS
defined as colloidal matter, but colloids are
material in the RAS water column would be
technology has flourished.
typically particles smaller than one (1)
made up of proteins, amino acids,
this, the Department for Environment, Food
In addition to
micrometre that do not settle and for which
phosphates, urea, humic acids and fatty
& Rural Affairs (DEFRA), Food and Agricul-
mechanical filtration is ineffective. A focus
acids.
ture Organization (FAO) and European
on the control of nitrogenous compounds
Commission have identified that political,
and suspended particulate matter without
Apart from the consumption of dissolved
social and environmental drivers favor
taking a closer look at colloidal matter will
oxygen during the biological degradation of
development of RAS as a sustainable source
have a number of detrimental effects on fish
organic matter, the breakdown of organic
of aquaculture for the future. However,
health and the biological and chemical
wastes by sheer forces and microbial
there are many challenges in a technological
processes controlling the removal of
degradation into other products could both
solution to filtering the metabolites of the
nutrients and particulate wastes from the
increase the total ammonia nitrogen as well
organisms cultured, beyond the removal of
system.
as support the growth of heterotrophic
macro- particulate matter. At AquaBioTech
bacteria affecting nitrification. The concen-
Group, these challenges are being met and
Typically, more than half of the dry weight
tration of both dissolved and colloidal
overcome using new, efficient and innova-
of the total solids in a RAS water column is
organic material also affects the prolifera-
Aquaculture Scoop / March Issue 2016
Page 16
tion Nitrosomonas spp., which is the bacterium in the biofilter, which converts ammonia into nitrite. This bacterium operates more efficiently under high organic loadings than Nitrobacter spp., which coverts nitrite to nitrate, and therefore, if this organic matter is not removed, then the levels of nitrite in the system can increase and be toxic to the cultured organisms. Studies have also shown that colloidal matter could irritate gill tissues providing preferential surfaces for attachment of detrimental bacteria, reducing fish health and hence immune- susceptibility, putting the stock at risk. Faeces followed by uneaten feed typically form the largest portion of suspended solids in the water column. The size distribution of the two sources of suspended solids together with their specific gravity differ greatly, with the majority of uneaten feed remaining larger than zero point five (0.5) mm despite being recirculated a number of times. The size distribution of both feed and faeces is determined by the feed composition as well as the species and size of the organism. A review of studies where particle size analysis was carried out in RAS showed that the vast majority of suspended particulate matter was smaller than twenty (20) micrometres and that there was a low degree of removal by the installed processes. A common removal method for colloidal
depends on a number of factors but the size
oxygen and poorer in double bonds due to
material in RAS is to pass a portion of the
of the particle is particularly important. The
increased hydroxyl, carbonyl and carboxyl
water from the biofilter through a saturation
minimum size for attachment typically
functional groups. Creation of the more
cone into which ozone is injected before
occurs for particles around one (1) micro-
polar functional groups can cause dissolved
flowing through a foam fractionation
metre. For this reason, methods for
organics to precipitate and can also produce
process. Foam fractionation works on the
agglomeration and flocculation are typically
polyelectrolyte characteristics among
principle that dissolved organic compounds
used to increase the size of colloids to
suspended particles that increase enmesh-
as proteins in the water have bipolar
increase the removal efficiency.
ment, adsorption and cross linking between
properties. These compounds attach to the
the solids, which in combination are
gas/liquid interface of air bubbles in water.
Through the process of oxidation, ozone
referred to as â&#x20AC;&#x153;micro-flocculationâ&#x20AC;?. Studies
When sufficient dissolved organic material is
precipitates dissolved organic matter and
have shown that the optimum dosage for
skimmed from the water, a stable foam is
acts as a micro-flocculent of colloidal
the flocculation of organic solids was
created and can be then removed from the
organic matter. Oxidized organic
primarily dependant on the Total Organic
system. The mechanisms involved in the
compounds are usually smaller and contain
Carbon (TOC) concentration and to a lesser
attachment of a particle to a bubble
more polar compounds that are richer in
extent the ratio of hardness to TOC. In
Aquaculture Scoop / March Issue 2016
Page 17
seawater systems, the addition of very small doses of ozone changes the charge on some particles so that they are more hydrophobic and therefore attach to the bubble surface. As the ozone concentration is increased, the surfactants attached to the bubble may instead break down into smaller hydrophilic parts. This makes for easier removal of the colloidal matter in the form of foam, which exudes from the water column. Development of new technology to make this process more energy efficient such as low pressure microfiltration membranes, having pores of between zero point one and one
such as this at AquaBioTechâ&#x20AC;&#x2122;s facility may
decrease and knowledge increases, further
(0.1â&#x20AC;&#x201C; 1) micrometres in pressurised or
change this, by designing a membrane
developments and progress will increase the
submerged configurations have still not been
process that is adapted for intensive RAS
effectiveness and efficiency of our systems.
proved to be an effective economic alterna-
systems by optimizing membrane configura-
Hence promoting the advancement of the
tive to traditional micro-screens, foam
tion, flux and fouling control mechanisms to
RAS filtration system design and the
fractionation and other technology. However,
minimize energy use. In addition, as the
long-term environmental sustainability of the
research and development into technology
price of membranes and other technologies
aquaculture industry.
Aquaculture Scoop / March Issue 2016
Page 18
Aquaculture Insurance: Is your most important asset covered? Aquaculture is high risk. As well as the risks
Financial (credit, liquidity & cash flow, etc.),
A number of new insurance products are
associated with animal production (disease,
Strategic (competition, industry changes,
available to farmers, and insurance solutions
reduced growth rates, natural mortality) fish
etc.), Operational (supply chain, regulation,
can be developed to suit individual needs
farms are often located in environments that
etc.) and Hazard (natural catastrophe, stock,
and budgets.
test equipment to their limits, and where
equipment and properties).
Insurance covers available
human error can have disastrous results. Some of these risks are insurable, but many Not all risks are insurable, but some of the
arenâ&#x20AC;&#x2122;t.
Biomass insurance
considering the cost of risk over time,
By using tried and tested techniques you can
This insurance covers the risks of mortality
insurance, very often, is a very efficient way
quickly get a broad sense of how much risk
of stock held on the farm site. This insurance
of transferring risk, and gives peace of mind
could be costing your company, even if you
covers the costs of production, and does not
to managers and investors.
have never had a loss.
insure against loss of profits, market price or
biggest risks facing an operation are. When
business interruption.
Calculating the Cost of Risk
Insurance is a valuable tool in the risk management tool box, and operational and
Live fish transits
The first step in Risk Management is to
natural hazard risks should be regularly
identify the risks facing your company.
assessed to ensure adequate protection is in
Biomass insurance can be extended to cover
Risk comes in many forms, and can be
place.
the risk of stock mortality while in transit
Aquaculture Scoop / March Issue 2016
Page 20
Biomass insurance can be extended to cover
Typical perils:
the risk of stock mortality while in transit between farm sites, or from hatcheries. Transit cover is typically only offered as an extension of the biomass policy.
Offshore equipment
OFFSHORE
ONSHORE
1. 2. 3. 4. 5.
1. 2.
Offshore floating equipment, cages and feed barges can be covered, however usually only for larger operations as minimum premiums tend to make this uneconomic for smaller farms.
Wordings – Biomass insurance
6. 7. 8. 9. 10. 11. 12.
• ‘All Risks’ Wording 13. An ‘All Risks’ policy protects against all risk of stock mortality unless specifically excluded within the wording. With these wordings the
14.
Pollution. Plankton bloom / red tide. Jellyfish attack / bloom. Theft and Malicious Acts. Predation, or physical damage caused by predators or other aquatic organisms (not sealice or other ectoparasites). Storm. Lightning. Tidal wave. Collision. Sudden and unforeseen structural failure of equipment. Freezing, Supercooling, Ice damage. Deoxygenation due to competing biological activity or to changes in the physical or chemical condition of the water, including upwelling and High water temperature. Any other change in concentration of the normal chemical constituents of the water, including change in pH or salinity. Disease.
onus is on the underwriter to demonstrate
3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
losses are not covered under the policy, whereas in the case of a Named Perils 17.
wording the onus is on the policy holder to
Theft and Malicious Acts. Predation, or physical damage caused by predators or other aquatic organisms (not ectoparasites). Flood. Tidal Wave. Storm Damage. Subsidence, Landslip, Structural Failure, Breakage or blockage of any part of the water supply system. Drought. Fire. Lightning. Explosion. Earthquake. Freezing, Frost damage, Frazil ice. Mechanical breakdown or Accidental damage to machinery and other installations. Electrical breakdown, Failure or interruption of the electricity supply, Electrocution. Deoxygenation due to vegetation, microbiological activity or high water temperature. Any other change in concentration of the normal chemical constituents of the water, including supersaturation with dissolved gases and change in pH or salinity. Disease.
demonstrate that the loss was a result of a peril named in the policy (see below). ‘All Risks’ policies are not always available,
Submission requirements
with underwriters reluctant to offer these
assessing how much premium to charge to transfer this risk. Most underwriters have
where species, locations, or farming risks
To enable an underwriter to accurately
significant experience in assessing aquacul-
are not fully understood by the underwriter.
assess the risks of a farming operation, the
ture risks, and some have come from the
following are required:
aquaculture industry so are generally
Depending on the operation, an ‘All Risks’ wording is typically around 5 – 10% more
knowledgeable about most species and 1. Proposal Form
systems in use.
A fully completed and signed proposal form
Please note this information will be part of a
will be needed (there are separate forms for
legally binding submission to insurers, and
offshore and onshore operations). The
as such the accuracy and truthfulness of the
expensive than a Named Perils policy (with all perils covered). • Named Perils Wording
information contained within the proposal
information supplied is critical. Any
Named Perils policies cover only those perils
form will provide underwriters with details
incorrect or fraudulent information may
chosen by the policy holder (or offered by
of the applicants farming ability, experience
prejudice a claim in the event of a loss.
the underwriter), and do not cover losses
and what monitoring and controls are in
falling outside of these.
place on which to base their risk assessment
Changes to the risk
on. The more information and detail that In Named Perils policies the onus is on the
can be supplied the better.
policy holder to prove that a loss falls within
Should there be significant and material changes to the operation (and therefore the
the scope of the policy, as a result of the
It should be remembered that the applicant
risk) during the period of the policy then this
perils covered.
is in effect asking insurers to accept their
should be declared to underwriters. Failure
production risk, and insurers will be
to do so may prejudice a claim following a
Aquaculture Scoop / March Issue 2016
Page 21
loss. If in doubt, declare any changes to your broker.
Sums insured and valuation of stock
exposure. The average biomass value is used to avoid any large premium adjustments at the end of a policy.
2. Deductible
Sums insured will be determined by the stock projection and basis of indemnity.
Premium instalments
the policy holder retains for each and every
The basis of indemnity is the value you
It is recognised that cash flow can be a
loss. Deductibles tend to be a percentage of
would like to be indemnified (paid) following
problem for companies involved in primary
the sum insured, rather than a fixed amount
a recoverable loss (after the application of
food production, with money often only
(excess). Excesses are very rarely used in
the deductible). Values should be based on
becoming available when product is sold. As
biomass policies due to the variation in
costs of production and not sale price. Many
a consequence insurers are willing to offer
exposure (stock levels) across the policy
policies have a provision within them to
premium instalments, however this results
period.
replace the fish with the same or similar
in them carrying a credit risk in doing so.
The deductible is the amount of the risk that
stock, so if values are inflated you may find
Insurers will sometimes consider premium
Due to the high risk nature of aquaculture,
that you will be charged more premium than
discounts, or may amend the policy in other
deductibles tend to be high when compared
necessary, with underwriters simply
ways, to favour policy holders paying
to less risky classes of insurance. Typically
replacing lost stock.
premiums up front.
deductibles per unit, per group, or even per
Basis of indemnity can be a value per kg
Premium instalments also come with
cage or tank are possible. Lower deductibles
(weight), a price per fish (or unit) or a
increased risks to the policy holder, as most
however come at higher premium cost as
mixture of the two (for example a fixed price
insurance policies have warranties in them
insurers are much closer to the risk of paying
per fish, to cover purchase price, plus a value
that could result in a claim being prejudiced
a claim, therefore charging more premium
per kg to reflect input costs over time).
if premium payments are not paid on time.
these tend to be applied on a site basis, but
to transfer the risk. 3. Stock Projections
In extreme cases cover automatically lapses Sums insured can be adjusted up or down
for non-payment of premium, so a policy
during the policy period with agreement
holderâ&#x20AC;&#x2122;s ability to pay the correct premium
from insurers, which might result in
on a given date is crucial.
Stock projections detail how much stock will
additional premium, or a return of premium
be on site during the policy period and
(depending on the minimum premium
should be calculated as a function of
charged on the policy).
biomass (usually kgâ&#x20AC;&#x2122;s or numbers) and the
5. Pre-risk surveys Increasingly pre-risk surveys are being used
basis of indemnity (valuation). Stock should
All stock on site needs to be insured. Under
to confirm the quality of an operation before
be detailed on a monthly basis.
insurance will lead to the application of
committing to an insurance policy. If the
average in the event of a claim if stock
operation is unknown to insurers then it may
cannot be identified as insured.
be that a pre-risk survey will be required
Having stock projections for the period of the policy is essential in determining an insurerâ&#x20AC;&#x2122;s financial exposure, and is used to
before quoting.
Natural mortality rate
calculate the premium charged. Most
The cost of any survey will usually be paid
operations will have stock information in one
Any farming system will have natural
for by the applicant in the first instance, with
form or another as part of their stocking
mortality. The natural mortality rate declared
the cost discounted from the premium if a
plan.
in the proposal form will have an impact on
policy is taken out.
any loss adjustment, as these will be During the policy stock declarations will need
removed from any claim payment.
to be sent in each month to monitor the sums insured on site and to make sure that
4. Rates and Premium
sufficient cover is in place to protect the policyholder.
Premiums are generally calculated on applying the insurance rate to the average sum insured on the policy, with insurers aiming to charge a fair premium for their
Aquaculture Scoop / March Issue 2016
More information: Dan Fairweather - BSc, MSc (Dist) Director - Aquaculture and Fisheries Willis Towers Watson, Willis Limited, UK Email: Dan.Fairweather@WillisTowersWatson.com Web: www.willistowerswatson.com
Page 23
Aquaculture will supply two-thirds of global fish consumption by 2030 Sign up to our FREE weekly newsletter Email us at seafood@nisamedia.com Source: World bank report
Aquaculture Scoop / March Issue 2016
Page 32
Major Breakthrough in Ammonia/Nitrite Control for Aquaculture No More Waiting for Nitrification . . . New Product controls Ammonia-Nitrite until Nitrification begins . . . Dublin, Ireland – 15th February 2016 They say you can’t teach an “old dog new tricks” ... but a small Bio-Tech company in Dublin, Ireland is about to change all that!
For more information contact:
Bio-Industries Ltd. has created FirstBIO, an
previously commercially available. These
extraordinary new natural biological
microorganisms can operate in a wide range
product that immediately starts to control
of normal and hostile water conditions and
J Strauss
Ammonia-Nitrite by using a novel method of
are bio-synergistic having the ability to
Bio-Industries Ltd
removal which no longer requires adding
significantly improve the biological action of
Unit 66D Heather Road
nitrifiers and waiting for nitrification.
other bacteria operating within the
Sandyford Business Park
processes.
Dublin 18
Ammonia/Nitrite removal is no longer
Ireland.
dependent on stabilizing water conditions to
The result of more than 3 years of intensive
Tel: + 41 79 301 9791
establish nitrifying populations to start the
manufacturing development, Bio-Industries
Email: joss@bio.ie
Nitrification Cycle. At the same time FirstBIO
Ltd. started field testing of FirstBIO in
improves overall water conditions by
mid-2014 and immediately realized that the
stabilizing pH which leads to healthier
product was superior to just adding
aquatic life and less stress. It can even
nitrifying bacteria and waiting for nitrifica-
control Ammonia-Nitrite levels in extreme
tion to begin. So now aquaculture operators
water conditions.
can get faster control of their water
ISO 14001:2004 & 9001:2008
conditions. FirstBIO is a very cost effective In test after test, FirstBIO continues to
ultra-concentrate and usage rates are based
astound users as to its unique capabilities. It
on water volume or filter capacity. It is
cannot only reduce high levels of
simply added to the water or filter as
Ammonia-Nitrite in as little as 24 to 96
required and during restocking.
hours but also stop them from occurring in a wide range of operating conditions. It has
Worldwide Distributor enquiries welcomed.
been shown to significantly reduce the lag time normally associated with establishing nitrifying populations to start the Nitrification Cycle. FirstBIO is like NO other product available because it is the only product to have been developed with a group of Class I microorganisms called “extremophiles” not
Aquaculture Scoop / March Issue 2016
Page 25
HOW TO USE AN AERATOR IN A POND Kajal Kumar Roy Singha Research and Development Engineer Sagar Aquaculture Pvt. Ltd. Rajkot, Gujarat
India is growing in the field of fresh water
more during the night following cloudy than
into the entire volume of water. Aerators
and brackish water aquaculture through
clear days. The rate of photosynthesis and
can be used exclusively for emergencies,
extensive and semi intensive cultivation
the rate of oxygen production vary with
continuously at night or throughout the
techniques. The production of fish, shrimp
light intensity, amount of algae present in
day and night. Aerators work by increas-
and other aquatic species in semi-intensive
pond system and duration of exposure to
ing the area of contact between air and
and intensive aquaculture operations
sunlight. In a culture pond more oxygen
water. Aerators also circulate water so that
depends on various water quality
must be produced in water than that is used
fish can locate the areas with higher oxygen
parameters; dissolved oxygen (DO)
by organisms, otherwise depletion of
concentrations. Various types of aerators
concentration is one of them. Dissolved
oxygen will occur. Rise in atmospheric
have been developed over the years to
oxygen is a very essential component for
temperature, causes increased rate of
maintain desired level of DO concentration
culture of aquatic animals and other
biological degradation of organic maters
in the pond and wastewater in an effort to
organisms in water body. Oxygen is
and subsequent depletion in DO concentra-
improve the energy efficiency of the
required respiration purpose. Naturally
tion in water.
oxygen mass transfer process. In
water receives oxygen through photosynthe-
aquaculture, propeller-aspirator- pump
sis process of aquatic plants and diffusion
The supply of oxygen to the water body is
aerators, diffused-air aeration system,
from the atmosphere through the surface
essential to increase the DO concentration.
paddle wheel aerators and spiral aerators
of water. In general, most fish species will
Aeration is the process of bringing water
are most widely used. These aeration
grow within a DO range of 5-12 mg/L (ppm).
and air in contact for diffusion of oxygen
systems can be broadly classified into three
If DO levels drop below 4 mg/L they may
into water required for aquaculture and
groups: mechanical surface aerators,
stop feeding, feel stressed and result reduce
biological wastewater treatment. However,
diffused-air aeration systems and
growth rate. Low dissolved oxygen does not
it is not uniform and gets affected by
subsurface mechanical aerators. Pond
cause mortality directly to the fish life in
various factors. Now a day, demand of
aeration systems have become very popular
the culture system, but leads to the
aquatic product is very high all over the
in the field of aquaculture during the past
deterioration of water quality, which
world. So for increase in the aquacultural
two decades. Paddle wheel aerators and
imparts stresses in fish body and in turn
production, additional aeration through
propeller-aspirator-pumps are probably
causes mortality. Ponds generally reach the
artificial aeration system is very much
most widely used aerators in the field of
minimum dissolved oxygen level during the
essential. A properly designed aeration
aquaculture. Most effective mechanical
mid-night or early morning. However, on
system is essential to maintain adequate
surface aerators are the paddle wheel and
cloudy days the dissolved oxygen concentra-
and continuous supply of DO to meet the
spiral aerators.
tion may reach the alarming level even
demand of the aquatic species. The aeration
during the daytime due to lack of photosyn-
system must also provide sufficient bulk
It is very important to know the dynamics of
thesis. The DO concentration will decline
liquid mixing to ensure proper mixing of DO
dissolved oxygen in an aquaculture system.
Aquaculture Scoop / March Issue 2016
Page 27
The actual quantity of oxygen that can be present in solution is governed by the solubility of the oxygen as defined by the
Average body weight (g) O2 demand (mg O2/h)
10 3.703
20 6.819
30
40
50
9.747
12.558
15.287
Henry’s law, partial pressure of the oxygen in the atmosphere, the temperature and the
Form the calculation of this equation it is
concentration of the impurities in the water
apparent that oxygen demand increase with
(e.g. salinity, suspended solids etc.). When air
increasing body weight of shrimp. Plankton
is in contact with water, oxygen enters the
takes oxygen from pond 1.34 kg O2/h at
water from the air until the tension of
night for their respiration requirement and
oxygen in the water equals the partial
produce CO2. Benthos required 0.61 kg O2/h
pressure of oxygen in the air. Even though
during night and day for their respiration in 1
the atmosphere contains nearly 21% oxygen,
hector pond with 1 m water depth.
oxygen gas is slightly soluble in water. Increase in temperature and salinity causes
Calculation of requirement of HP for culture
a corresponding decrease in oxygen
pond:
concentration. Oxygen solubility is also influenced by the atmospheric pressure. Oxygen saturation decreases as elevation
Example 1:
makes the surface rough and thereby
Calculation Table Length x Width water depth (m) Depth of pond (L X W X D) m Stocking density No of shrimp/ m3 Salinity (ppt) Average body weight (g) Total density of shrimp water salinity Body weight of shrimp Water volume x density Values from table HP requirement for shrimp Value from table HP/one lakh shrimp Extra HP requirement for day Value from table HP/10000 m Extra HP requirement for night Value from table HP/10000 m Aeration Requirement for culture pond (HP requirement for shrimp X total density of HP requirement for fish HP shrimp) ÷1,00,000
increases surface area. Mixing also causes
HP requirement for day
above mean sea level (MSL) increases, due to corresponding decreases in pressure. The pressure of oxygen in air drives oxygen into water until the pressure of oxygen in water is equal to the pressure of oxygen in the atmosphere. The importance of water mixing (turbulence) on oxygen transfer between the atmosphere and water is apparent. Mixing
mass transfer (convection) of water and dissolved oxygen from the surface to different locations within the water body. Presently farmers are using aerator blindly.
Pond area (m x m) Volume of water (m ) Temperature (ºC) water temperature
(Extra HP requirement for day X pond water volume) ÷ 10,000 (Extra HP requirement for night X pond water volume) ÷ 10,000 HP requirement for aeration in the culture pond HP requirement for shrimp + HP requirement for day HP requirement for shrimp + HP requirement for night
HP requirement for Night Day Night
HP HP
They don’t bother regarding function of aerator in pond water and how much
Example 2:
artificial DO required for culture pond. For that reason we have calculated for 1 ha (100 m X 100 m) pond with 100000 seeds in a farm for 1 m depth of water. Now let us discuss DO requirement for shrimp: Oxygen requirement per unit body weight should be found out. For example, for shrimp respiration, the empirical equation is: Od (mg O2/h) = 0.487 W0.881. Where, Od = oxygen demand of shrimp in mg/h, and W = average body weight of one shrimp in gram. This requirement multiplied by the number of total shrimps will give the respiration requirement.
Aquaculture Scoop / March Issue 2016
Calculation Table 100 80 water depth (m) 1.5 100X80X1.5 = 12000 Stocking density Average body weight Total density of Temperature (ºC) Salinity (ppt) (g) shrimp 28 25 20 350000 Values from table HP requirement for shrimp 2.2 HP/one lakh shrimp HP requirement for day 1.95 HP/10000 m HP requirement for night 6.25 HP/10000 m Aeration Requirement for culture pond HP requirement for fish 7.7 HP (2.2 X 350000)/ 100000 HP requirement for day (1.95 X 12000)/10000 2.34 HP HP requirement for Night (6.25 X 12000)/ 10000 7.5 HP HP requirement for aeration in the culture pond 7.7 + 2.34 = 10.04 (take 10 HP) Day Night 7.7 + 7.5 = 15.2 (take 15 HP) Pond area (m x m) Volume of water (m )
Page 28
This contribution helps to save electricity
Example 3:
Calculation Table Pond area (m x m) 90 90 water depth (m) 1.5 Volume of water (m ) 90X90X1.5 = 12150 Stocking density Average body weight Total density of Temperature (ยบC) Salinity (ppt) (g) shrimp 32 20 29 250000 Value found from table HP requirement for shrimp 3 HP/one lakh shrimp HP requirement for day 1.86 HP/10000 m HP requirement for night 5.94 HP/10000 m Aeration Requirement for culture pond HP requirement for fish (3 X 250000)/ 100000 HP requirement for day (1.86 X 12000)/ 10000 HP requirement for Night (5.94 X 12000)/ 10000 HP requirement for aeration in the culture pond Day 7.5 + 2.23 = 9.73 (take 10 HP) Night 7.5 + 7.13 = 14.63 (take 15 HP)
7.5 2.23 7.13
HP HP HP
consumption. Our electric motor can work in voltage fluctuation also. Single mould impeller gives more oxygen and good water current. Heavy weight L angle stainless steel frame holds the aerator firmly so that performance will be higher. All UV resistance plastic parts get minimum 5 years life in sunlight. This way, we serve quality product to aquaculture industry.
Spiral aerator: Spiral aerator (Fig. 2) is specially designed for high dissolve oxygen in aquaculture. Spiral RPM is more than paddle wheel aerator in
Example 4:
the air with small droplets to increase air water surface contact. Spiral is the best
Calculation Table 100 100 water depth (m) 1.5 100X100X1.5=15000 Stocking density 250000 Average body weight Total density of Temperature (ยบC) Salinity (ppt) (g) shrimp 28 35 35 250000 Value found from table 3.47+(4.47-3.47)X5/10=3.97 *For 35 g average body weight of HP requirement for shrimp shrimp we can take HP requirement HP/one lakh shrimp value for 40 g of fish (4.47). Else we have to calculate above this method. HP requirement for day 2.17 HP/10000 m HP requirement for night 6.94 HP/10000 m Aeration Requirement for culture pond HP requirement for fish (4.47X 250000)/ 100000 11.17 HP HP requirement for day (2.17 X 15000)/10000 3.255 HP HP requirement for Night (6.94 X 15000)/10000 10.41 HP HP requirement for aeration in the culture pond Day 11.17 + 3.255 = 14.42 (take 15 HP) 11.17 10.41 = 21.58 (take 22 HP) Night Pond area (m x m) Volume of water (m )
option for improving dissolve oxygen level in water column. Semi intensive and intensive culture spiral should use with paddle wheel aerator to get more profit. We developed 2 and 3 HP spiral.
Long arm aerator: We require good soil quality that can hold the water, available and plenty of water and electricity for develop aquaculture farm. The place we select is may be suitable for our aquaculture. But their electricity availability may be fluctuated. For solving this problem we developed long arm paddle wheel and spiral aerator that can run with diesel engine is shown in the Fig. 3.
Sagar aquaculture Pvt. Ltd. developed new equipment to contribute aquaculture
Fig. 1 Pictorial view of paddle wheel aerator: (a) 1 HP, (b) 2 HP and (c) 3 HP
industry. And successfully we are helping farmers and aquaculture industry. Now we give information of aeration equipment from our contribution.
Paddle wheel aerator:
(a)
Paddle wheel aerator is specially design for extensive and semi intensive culture systems is shown in the Fig. 1. We developed high efficiency electric motor and bevel type gear
(b)
box for 1, 2 and 3HP paddle wheel aerator.
Aquaculture Scoop / March Issue 2016
Page 29
Submersible aerator: Submersible aerator (Fig. 4) is help full to dissolve more oxygen and produce less water current. It can suck more air from nature and throw in the water and create micro fine bubble to dissolve more oxygen.
(c)
Roots blower: Now a day roots blower is widely used in aquaculture purpose. Roots blower produced high pressure with large volume of air. Aqua animal can get enough oxygen with less electric power. Roots blower and aero tube, oxygen will maintain from bottom to surface of the pond. Roots blower mainly use in feeding time. It is very easy to install and maintain cost also less.
Fig. 2 Pictorial view of spiral aerator
(a) !
Fig. 4 Pictorial view of Submersible propeller aerator
(b) Fig. 3 Pictorial view of long arm (a) paddle wheel aerator and (b) spiral aerator
Aquaculture Scoop / March Issue 2016
Page 30
Worms transforming wastewater treatment practices
Environmental compliance is one fact of life
companies could afford on site treatment of
Company (Wastewater Wizard) has refined
all facets of the aquaculture industry must
the foul smelling soup that is sludge. Most
their Wizard range of technology to treat
comply with. More so for the on shore fish
companies settle for the waste management
sludge. For the first time this development
farms, hatcheries and food processing
option which involves tankering it off site for
allows on shore operations the option to
facilities, where dilution rates from the
processing elsewhere. If the installation is
treat sludge on site in a cost effective
surrounding water body play no part.
near agricultural land then spreading it as a
manner.
Leaving aside the complex low load/high
low grade fertiliser is an option. For a few
flow conundrum there are many technolo-
large scale operators, investment in
The first thing you notice about vermifiltra-
gies available to treat the vast quantities of
anaerobic digestion can provide a return by
tion technology is its compact size. The
wastewater. These fall into three categories
generating energy from biogas, it stills
Wizard system is no different in this respect
and are either biological, chemical or
leaves a residual sludge.
as it is a single stage treatment process with
physical processes. Companies will pick the
a bed depth ~1m deep. The bed or to be
most suitable technology balancing cost,
In recent years a new innovative technology
more accurate the vermifilter is made up of
energy requirement and the availability of
has come to market, treating sludge which
several layers containing various grades of
land.
has an unlikely organism at its heart – the
aggregate which supports the media above.
lowly worm. Vermifiltration in simple terms
The media or to be more precise is coir, a
Once the wastewater treatment box has
is a worm filtration technology; the term
waste product derived from coconut husks.
been ticked, it then follows that the next
“vermi” is derived from the Latin name for
It is in the upper most layers of the coir
issue faced by the operator is what to do
worm. Though the origins of this technol-
where the worms live. The sludge is
with (what seems like) endless volumes of
ogy is unclear it was pioneered in the UK,
distributed over the surface and it perco-
sludge the treatment process generates.
Chile and Australia. Today we find that the
lates down filtering out the solids and
Although on a much smaller scale that that
largest installations are found in South
organic component. This material becomes
generated by the industry, it does however
America, with 100’s of plants mainly treating
the worm’s food source.
come at a cost. Up until now very few
industry wastewater. In the UK one
Aquaculture Scoop / March Issue 2016
Page 31
WASTEWATER
COCONUT FIBRE (inc. worms, micro ecosystem & vermicast)
Wastewater percolates down, trapping the solids and organics
UNDER DRAIN/MEDIA SUPPORT
FINAL EFFLUENT
Worms thrive in this environment and the
of the distribution arm motor and a small
area there are ~10,000 worms, coupled with
sludge is an ideal food source. After a single
pump station to lift the sludge onto the
a high reproductive cycle with a high protein
pass up to 95% of contaminates (suspended
distribution arm. The capital spend profile
content of up to 60% of body weight, they
solids and BOD) are removed. The resulting
is low compared to the conventional sludge
could lend themselves to reduce the burden
treated effluent has similar make up of that
treatment technologies.
of fish derived protein used in fish food.
of domestic sewage, and is easily treated by
Academics studies have already started
on-site wastewater treatment plant with
As you would expect ongoing maintenance
looking at this solution, but Wastewater
little impact.
is simple. Routine tasks are carried out
Wizard for now is taking it one step at a
using pitch forks, so there is no need to
time. Yesterday was developing wastewater
Unlike the conventional tanker lead
spend time upskilling the workforce. There
treatments systems, they have now adapted
operation, sludge treatment can be
is a by-product produced by the worms.
the system to treat sludge. Solving the fish
achieved on site. The type of worm used
Worm casts are excreted by the worms as
food protein problem will be left for another
within the Wizard system is a key compo-
they feed. This solid material is trapped
day.
nent to its success. Using the worm species
within the media, and over time builds up
Eisenia fotida, they can digest up to its
causing an ever increasing surface level.
entire body weight in sludge each day. This
Removal is carried out by using the same
means that these systems have a low
pitch fork for the routine maintenance. The
footprint due to the relatively high loading
worm casts are high in nutrients, (nitrogen,
rates achieved. In relative terms they can
phosphorus and potassium) and could lead
treat 6 â&#x20AC;&#x201C; 10 times the wastewater load
to an additional revenue stream selling to
achieved by the traditional constructed
agriculture. There is an abundant scientific
wetland.
literature relating to the additional value
More information: Kevin Jeffrey Wastewater Wizard Ltd., Tel: +44 1381 620 413 Web: www.wastewaterwizard.co.uk
these bring to farmers in increased crop Simplicity is a by word for this technology.
yield coupled with a lower requirement to
The natural burrowing action by the worms
buy in manmade fertiliser.
ensure an aerobic environment throughout
One avenue that Wastewater Wizard is
as they need air to breath. Energy consump-
aware of but not yet exploited are the
tion is low as the only power required is that
worms themselves. For every m2 of bed
Aquaculture Scoop / March Issue 2016
Page 32
AQUACULTURE EQUIPMENT Sagar Aquculture Pvt.Ltd. has been established in Year 2001, with the manufacturing of Fishing Floats and Long Arm Impeller only. When we find out that in imported Paddle Wheel Aerator there are so many problems about parts avilability & services, so we decide to solve those problems by manufacturing complete Aerator in India. Since 2012 we start to manufacturing of Paddle Wheel Aerator. Day by day, we find that Aquaculture industries require many othermodified products which can help them as an auto solution. So as per their demand we developed many others products like Spiral Aerator, Six Paddle Aerator, Mud Lifting Machine (Sludge Pump), Auto Feeding Machine, Long Arm Aerator, Long Arm Spiral, Submersible Aerator etc.
Events in detail January 20th Edition India International Seafood Show 22-24th January Chennai, India www.indianseafoodexpo.com/ MVC Cereals-Mixed Feed Veterinary 2016 26-28 January Moscow Russia www.mvc-expohleb.ru/ Practical Short Course on Feeds & Pet Food Extrusion 31st January – 5th February Texas, USA http://foodprotein.tamu.edu/extrusion February SeaWeb Seafood Summit 1-3rd February St Julian’s, Malta www.seafoodsummit.org/ Fish International 14-16th February Bremen, Germany www.fishinternational.com/en/ Aquaculture 2016 22-26th February Las Vegas, USA www.was.org March Seafood Expo North America 6-8th March Boston, USA www.seafoodexpo.com/north-america/ AquaMe 13-15th March Dubai, UAE www.agramiddleeast.com/en/Aqua/ Seafood Istanbul 23-26th March Istabul, Turkey http://cnrseafoodistanbul.com
Aquaculture Scoop / March Issue 2016
Aquafeed Horizons Asia Conference 29th March Bangkok, Thailand http://feedconferences.com/ Victam Asia 29-31st March Bangkok, Thailand www.Victam.com April Offshore Mariculture Conference 6-8th April Barcelona, Spain www.offshoremariculture.com/europe Seafood Expo Global 26-28th April Brussels, Belgium www.seafoodexpo.com/global/
June Future Fish 2016/Middle East Aquaculture Forum (MEAF) 2-4th June Izmir, Turkey www.eurasiafairs.com AquaVision 13-15th June Stavanger, Norway www.aquavision.org/ July 2nd Global Summit on Aquaculture & Fisheries 11-13th July Malaysia http://aquaculture.global-summit.com/ August
Asia Pacific Aquaculture 2016 26-29th April Surabaya, Indonesia www.was.org
Asean FishExpo 2016 4-6th August Bangkok, Thailand www.aseanfishexpo2016.com/
May Aquafeed Extrusion Technology Short Course 9-11th May Norway www.fie.com.au Food & Feed Drying Technology Short Course 12-13th May Norway www.fie.com.au 7th World Fisheries Congress 23-27th May Busan, South Korea www.fisheries.org Aquaculture UK 25-26th May Aviemore, Scotland www.aquacultureuk.com/
Nor-Fishing 16-19 August Trondheim, Norway www.nor-fishing.no/?lang=en 11th International Conference on Recirculating Aquaculture & 2016 Aquaculture Innovation Workshop 19-21st August Roanoke, USA www.recircaqua.com Shanghai International Fisheries & seafood Exhibition 2016 (SIFSE) 25-27th August Shanghai, China www.sifse.com China International (Guangzhou) Aquaculture Exhibition 2016 26-28 August Guangzhou, China www.aquaexpochina.com
Page 35
Industry Report: Top 25 Salmon Farming Companies Worldwide Salmon farming is one of the most interesting and closely followed sub-sectors of the global aquaculture industry. Its top 25 companies are constantly changing, either through success, failure, expansion or acquisition. This detailed report presents both
key financial and harvest data, ranking the top 25 Salmon producers worldwide and giving insight into activities, locations, history, and owners. NOW AVAILABLE in printed copies delivered to your desk or as a digital download for UKÂŁ350
Email us or visit our website for more information: seafood@nisamedia.com www.aquaculturedirectory.co.uk