Aspects of Fish Ecology in the Alde & Ore Estuary Complex - 2016
Smelt Osmerus eperlanus
Watercolours by Colin Newman
Synopsis 1. 2. 3. 4.
Background to estuarine fish surveys Environment Agency WFD Alde & Ore fish survey data Marine conservation zone Hazelwood marshes fish sampling 2016
The need for partnership. Only 25% of estuaries are sampled and almost no saltmarshes are sampled at all. Most photos by Andrew Excell, Suffolk WT
Kick sampling
6 yr cycle, Reference Conditions & Programmes of Measures Only 25% of estuaries are sampled and no saltmarshes
Colclough et al, 2002 Coates et al, 2007
Fish Survey Sites in the Alde & Ore Estuary Complex
Hazelwood Marshes
Environment Agency WFD TraC Survey Sites 2003-2006 & 2013-2015
Iken Cliffs Aldeburgh
IFM & Suffolk WT Survey 2016
RSPB Reserve
Shingle Street Upper
Boyton Dock
Functional guilds of fish species in estuaries •
Estuarine residents (ER) – Fishes that spend their entire life in estuaries
•
Marine seasonal species (MS) – Fishes that use estuaries for part of the year
•
Freshwater species (FW) – Fishes that are present mainly or exclusively at low salinity values
•
Marine juvenile species (MJ) – Fishes that use estuaries as nursery grounds or during juvenile phases of their life cycle
•
Diadromous species (CA) - species that migrate between fresh and saltwater during different life stages
•
Marine adventitious species (MA) – species that are considered fully marine but inhabit estuaries temporarily
After Elliott and Dewailly, 1995; Hemingway and Elliott, 2002
Fish species captured in Environment Agency surveys 2003-6 & 2013-15 Euryhaline
Middle &
Lower Estuary
Fully marine
Bass
Black Goby
Pogge
Ballan Wrasse
Common Goby
Bull Rout
5 Bearded Rockling
Bib
Eel
Cod
Snake Pipefish
Butterfish
Flounder
Dab
Sole
Common Dragonet
Sand goby
Greater Pipefish
Sprat
Common Sea Snail
Sand smelt
Herring
Thick lipped grey mullet
Lesser Weever
Smelt
Lesser Pipefish
Thin Lipped Grey Mullet
Pollack
3 Spined stickleback
Long Spined Sea Scorion
Transparent Goby
Twaite Shad
Plaice
Viviparous Blenny
34 species and 5757 individual fish captured in total
Marine Conservation Zones
www.balancedseas.org.uk
Illustrative length frequency distributions from the 2010 report Bass Autumn 2005 Boyton Dock
RSPB Reserve
Illustrative length frequency distributions from the 2010 report Iken Cliffs Herring Autumn 2003
Sprat Autumn 2005
Illustrative length frequency distributions from the 2010 report Iken Cliffs Smelt Autumn 2003
Plus 2 fish in the autumn of 2003 at Iken Cliffs and 1 fish at Shingle Street in the autumn of 2005
Illustrative catches from the 2013-2015 data series Bass Site
Period
Number
Size range (mm)
Iken Cliffs
Spring 2014
5
54-76
Iken Cliffs
Autumn 2014
102
56-104
Iken Cliffs
Spring 2015
2
78-90
Iken Cliffs
Autumn 2015
100
30-72
Smelt Site
Period
Number
Size range (mm)
Iken Cliffs
Spring 2014
13
82-112
Iken Cliffs
Autumn 2014
97
70-124
Iken Cliffs
Spring 2015
8
53-125
Iken Cliffs
Autumn 2015
49
64-116
Herring Site
Period
Number
Size range (mm)
Iken Cliffs
Spring 2014
44
104-185
Iken Cliffs
Autumn 2014
100
50-87
Iken Cliffs
Spring 2015
38
55-194
Iken Cliffs
Autumn 2015
23
70-105
RSPB Reserve
Spring 2013
104
48-119
RSPB Reserve
Autumn 2013
76
53-78
RSPB Reserve
Spring 2014
2
86,114
RSPB Reserve
Autumn 2014
101
50-85
RSPB Reserve
Spring 2015
101
40-61
RSPB Reserve
Autumn 2015
25
45-80
Herring (continued) Site
Period
Number
Size range (mm)
Shingle Street
Spring 2013
86
33-73
Shingle Street
Spring 2014
100
39-63
Shingle Street
Autumn 2014
52
43-72
Shingle Street
Spring 2015
3
53-136
Boyton Dock
Spring 2013
109
45-67
Boyton Dock
Autumn 2013
34
49-70
Boyton Dock
Spring 2014
96
46-67
Boyton Dock
Autumn 2014
7
63-75
Boyton Dock
Spring 2015
102
42-57
Boyton Dock
Autumn 2015
23
56-80
Some brief preliminary conclusions about the fish communities in the Alde & Ore system 1. The 2013-15 data set is entirely consistent with the earlier 2003-2006 data set. 2. The community of fishes in the estuary is typical of those East coast estuaries with limited freshwater inputs, significant saline penetration and sluice structure truncation of normal estuarine processes. 3. The estuary acts as significant nursery for herring, with juveniles present in both spring and autumn at all sites. At least two year classes are present. Sprat display a similar distribution, but at lower densities and the species does not seem to penetrate to Iken Cliffs. 4. The estuary acts a significant nursery for bass, with most fish present at Iken Cliffs. At least two year classes are present. Numbers appear to be greater in the autumn months. 5. The 2013 – 2015 data set shows a significant nursery ground for smelt at Iken Cliffs. Numbers are greater in the autumn. There is evidence of local recruitment, with at least three year classes present. Together with the earlier data set from 2003-2006 and the findings of the 2013 national smelt status review, there is now ample evidence of a selfsupporting smelt population in the system.
Evidence of spawning at Langham Bridge in the freshwater reaches in 2003.
Colclough and Coates, 2013
Smelt in the river Burn , North Norfolk
Eastern IFCA NN RT
Colclough et al, 2005
Lessons Learnt
Habitat Issues
Hazelwood Marshes July & September 2016
60 plus planned breaches (managed realignments) have been constructed in the UK since the early 1990’s. Only 9 have been sampled for fish so far. Natural breaches are rare, so far, and none have been sampled for fish.
Hazelwood Marshes Fish sampling methods
Hazelwood Marshes Fish processing
Summary results of fish sampling at Hazelwood Marshes in July & September 2016 Total Number captured Species
Bass Common Goby Sand Goby Eel Thin lipped grey mullet Sand smelt Flounder Pipefish 3 spined stickleback
TOTAL ALL SPECIES
After Thompson S., 2016
Dicentrarchus labrax Pomatoschistus microps Pomatoschistus minutus Anguilla anguilla Liza ramada Atherina presbyter Platichthys flesus Syngnathus spp Gasterosteus aculeatus
Jul-16 71 2361 6 14 59 87 209 3 745
Sep-16 73 3943 0 0 431 103 6 0 82
3555
4638
Hazelwood Marshes Length frequency distributions for the most common species captured
After Thompson S., 2016
Hazelwood Marshes Length frequency distributions for the most common species captured
Hazelwood Marshes Some of the fish species captured
Flounder & 3 Spined Stickleback
Eel
Common Goby
Hazelwood Marshes Some of the fish species captured
Thin Lipped Grey Mullet
Bass
Pipefish
Bass & Thin Lipped Grey Mullet
Hazelwood Marshes Sampling Locations July 2016
The future?
Ecosystem services evaluation
Thank you!