Understanding what these species need to thrive

Lumpfi sh

need love too

Lumpfi sh and Ballan wrasse have their own welfare issues, which should not be ignored

Fish species such as lumpfi sh and Ballan wrasse, are increasingly being used as cleaner fi sh to help control the numbers of sea lice in salmon and trout pens.

Of course, the cleaner fi sh themselves also have welfare issues. They cannot survive on sea lice alone, and can suff er high rates of mortality when simply placed in a salmon pen without a proper feeding and welfare regime. Clearly, tackling one welfare (and ethical) challenge is not helpful if it simply creates another problem.

Harves� ng wild wrasse and lumpfi sh for this purpose also depletes fi sh stocks, so these species are now also being farmed. Unlike salmon, for example, which have been domes� cated for 50 years, lumpfi sh and wrasse have been farmed for a much shorter � me and there are s� ll gaps in the industry’s knowledge about them.

A group of researchers at Swansea University, including Professor Carlos Garcia de Leaniz, Chair in Aqua� c Sciences and Biosciences, drew on the exper� se and experience of par� cipants from the fi sh farming sector, animal welfare, academia and regulators to assess consensus on the main

Above: Lumpfi sh

challenges and poten� al solu� ons for lumpfi sh welfare.

The study (Addressing the welfare needs of farmed lumpfi sh: Knowledge gaps, challenges and soluti ons, July 2021) used a “Delphi” approach to see how the experts viewed the usefulness of fi ve behavioural and 12 physical welfare indicators. The Delphi method is a quan� ta� ve, ques� onnaire-based technique that aims to iden� fy a consensus among experts.

The researchers did indeed fi nd a consensus, iden� fying for example that fi n erosion and body damage were the most useful and prac� cal opera� onal welfare indicators, while blood parameters and behavioural indicators were seen as the least prac� cal.

One thing that became clear was – to state the obvious – lumpfi sh are not Atlan� c salmon. Applying a common set of welfare standards and standard opera� ng procedures to both species, even if they are co-habi� ng in the same pens, is not likely to be in the interests of the cleaner fi sh.

The researchers also iden� fi ed 16 prac� cal solu� ons for improving the welfare of lumpfi sh. In summary, these are: 1. Adopt welfare guidelines specifi cally developed for this species. 2. Train staff in their use and implementa� on. 3. Monitor fi sh o� en and look for early signs of poor welfare. 4. Watch for underweight fi sh and adjust feeding

ra� ons, feed frequency and feed delivery accordingly. 5. Monitor mortality rates regularly and inves� gate whether mortality exceeds the norm (defi ned by the median and the 10th-90th percen� le historical benchmark 114. 6. Keep densi� es within op� mal values for the species, typically 7. Screen-out lumpfi sh with deformed suckers at the earliest opportunity. 8. Reduce poten� al disturbance and handling as much as possible. 9. Provide shelters and cover in tanks. 10. Check water quality regularly. 11. Grade frequently, as adequate for the size and condi� on of the fi sh. 12. Vaccinate against infec� ous diseases. 13. Avoid areas with strong currents or outside the op� mal thermal niche. 14. Avoid prolonged transport whenever possible and check water quality during transport. 15. Be prepared to cull fi sh with subop� mal welfare under veterinary advice. 16. Slaughter lumpfi sh humanely.

Meanwhile, researchers at the University of S� rling’s Ins� tute of Aquaculture have also been addressing the lumpfi sh issue. Their conclusion is that measuring growth weight is a be� er indicator of health than commonly used indicators such as fi n damage. The Ins� tute team also developed a new tool to assess lumpfi sh welfare, which should help fi sh farmers to detect problems and take remedial ac� on where required. Dr Sonia Rey Planellas at the Ins� tute of Aquaculture has established a “Lumpfi sh can some� mes grow very fast, which leads farmers to introduce them too early” CUSTOMISED DESIGN OF KELP HIDES IN SEVERAL DIFFERENT MATERIALS

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correla� on between lumpfi sh growth weights and health outcomes.

She says: “At the moment, in the UK we use Opera� onal Welfare Indicators (OWIs) for fi sh welfare, but lumpfi sh are a diff erent shape to many other fi sh, so it’s about iden� fying the best indicators for each species.

“Fin damage is typically the indicator that is used, but in this study we found a more useful indicator was the correla� on between growth weight rela� ve to size and welfare.”

The researchers developed four indices based on weight and length comparisons, correlated with the OWIs for lumpfi sh, to develop a formula that calculates an overall score of above or below 2.8 (for other fi sh the fi gure is 3). Above 2.8 means the fi sh is fi ne, below means the condi� on is sub-op� mal and farmers must take remedial ac� on. Farmers input their measurements into a free online tool.

“It can help farmers calculate op� mal � mes to introduce the lumpfi sh to the salmon, for example,” says Dr Rey Planellas. “Lumpfi sh can some� mes grow very fast, which leads farmers to introduce them too early, when the waters are s� ll too cold. This is not good for welfare outcomes.”

Lumpfi sh are quite dis� nct from most farmed fi sh in terms of their body shape and behaviour, so the OWIs used to assess the health of salmon, for example, are not necessarily good indicators of cleaner fi sh health.

The researchers collected data from 456 fi sh from two diff erent environments: a hatchery at Ardtoe in Scotland and in salmon sea cages in the Faroe Islands and Scotland, in condi� ons approved by the University of S� rling’s Animal Welfare and Ethical Review Body.

The paper, Using model selecti on to choose a size-based conditi on index that is consistent with operati onal welfare indicators, is published in the Journal of Fish Biology.

The project was a collabora� on between the University of S� rling, including modelling by lecturer Bruce McAdam; the Sco� sh Aquaculture Innova� on Centre (SAIC); the Fisheries Society of the Bri� sh Isles (FSBI) and several salmon companies.

Jim Treasurer, a scien� st with Fai Farms near Fort William, worked on the study. He says: “This tool will help farmers iden� fy fi sh that are below average condi� on for the popula� on in the cage, and will indicate a need for prompt, remedial ac� on, such as modifying feed.”

Ralph Bickerdike, Head of Fish Health and Welfare at Sco� sh Sea Farms, who par� cipated, adds: “The welfare indicators iden� fi ed from the project have since been adopted at those of our farms using lumpfi sh to help control sea lice levels and have proven hugely helpful in ensuring high welfare standards among our cleaner fi sh.”

Meanwhile a study by a group of researchers is aiming to determine the best possible condi� ons to help Ballan wrasse to grow and thrive.

The project builds on more than 10 years of Ballan wrasse research led by the University of S� rling’s Ins� tute of Aquaculture and will explore a range of nutri� onal and environmental factors.

O� er Ferry Seafi sh, BioMar, Sco� sh Sea Farms, Mowi, and the Sustainable Aquaculture Innova� on Centre (SAIC) are suppor� ng the research, which could improve the robustness, welfare and resilience of Ballan wrasse when deployed into salmon pens.

Ballan wrasse display complex behavioural traits throughout their lifecycle, culmina� ng in their sea lice foraging ac� vity. Scien� sts believe hatchery processes during their early development may not only impact on their performance and welfare, but also their ability to become eff ec� ve delousers at sea. Determining the op� mal condi� ons – par� cularly as they grow in hatcheries – could be transforma� onal for the sector’s approach to sea lice treatment. The outcomes of the research project could also be used to scale up hatchery produc� on.

Professor Herve Migaud from the University of S� rling’s Ins� tute of Aquaculture says: “Years of research have taught us that Ballan wrasse are a complex fi sh species. Their behaviour can be signifi cantly impacted by environmental factors from a very early developmental stage including the nutrients they are given, especially as they have a rudimentary diges� ve system without any stomach. “In the wild, it can be a case of survival of the fi � est, and the fi sh tend to develop a level of resilience that we are aiming to understand and recreate in a controlled environment. Exploring the impact of diff erent variables in the hatchery process, in par� cular, can help us to create the best possible condi� ons to help the fi sh thrive and prepare them for when they are deployed into a salmon farm. “The demand for cleaner fi sh is growing and the aim is to get to a point where we can meet the demand for healthy and eff ec� ve hatchery-reared Ballan wrasse and enable the sector to reach full reliance on farmed rather than wild cleaner fi sh in coming years, ul� mately helping salmon farmers with a sustainable solu� on to sea lice.”

Researchers will also look at the nutrients in the feeds, such as vitamins and minerals, needed by Ballan wrasse from the fi rst feeding and weaning stages to support bone and car� lage health and minimise the risk of deformi� es, exploring the use of supplements, immunos� mulants and func� onal feeds to improve resistance to bacterial disease. These will help to be� er prepare Ballan wrasse for what they experience in the waters of a fi sh farm. The private sector is also fi nding ways to help care for the cleaner fi sh. Feed companies have developed bespoke feeds for cleaner species – for example, World Feeds’ VAF Fee Blocks have been developed to provide a balanced diet, delivered in a formula that suits the cleaner fi sh’s natural grazing behaviour. Meanwhile Norway-based Aquasolu� ons off ers bespoke “recapture hides” to help with the effi cient and gentle recapture of wrasse and lumpfi sh – recrea� ng the kelp in which the cleaner fi sh like to shelter.

Cleaner fi sh play an important role in protec� ng farmed fi sh, but their own welfare should also be an important considera� on. FF

“Years of research have taught us that Ballan wrasse are a complex fi sh species”

Top left: Ballan wrasse Above: Herve Migaud Below: Jim Treasurer