Fish Productivity in the South West
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Fish productivity in the south west Assessing small pelagic fish populations South West Marine Ecosystems Conference 2014 Friday April 4 th 2014, PML, Plymouth Jeroen van der Kooij Centre for Environment, Fisheries and Aquaculture Science
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Assessing small pelagic fish populationsJeroen van der Kooij, Centre for Environment, Fisheries and Aquaculture Science
Transcript of Fish Productivity in the South West
Fish productivity in the south west Assessing small pelagic fish populations
South West Marine Ecosystems Conference 2014
Friday April 4th 2014, PML, Plymouth
Jeroen van der Kooij
Centre for Environment, Fisheries and Aquaculture Science
Overview
• What and Why?
• How?
• Some results
• Future
Existing knowledge/data
• Sprat
– Lyme Bay fishery
• Sardine
– Herring versus sardine periods (e.g. Southward et al. 1988)
– Changes in sardine spawning seasonality (e.g. Coombs et al.
2010)
• Anchovy
– Increase in North Sea since mid-90s (Beare et al., 2004),
increase landings in English Channel (2000s)
– “Northern population” (Petitgas et al., 2012; genetic)
• Mackerel nursery area (fishery closed in early 90s)
• Horse mackerel?
Existing knowledge/data
• Data:
– L4
– CPR
– Commercial landings data
– bottom trawl survey data
0
5000000
1980 1990 2000 2010 2020
SPR
0
5000000
10000000
1980 1990 2000 2010 2020
PIL
0
2000000
4000000
6000000
1980 1990 2000 2010 2020
HER
0
200000
400000
600000
800000
1000000
1980 1990 2000 2010 2020
ANE
POSEIDON (DEFRA MF1112)
• Estimate population size of small pelagic species in SW
• Explore ecological drivers of distribution and abundance
• Pelagic foodweb
• Five multi-disciplinary surveys (2012-2016)
Pelagic fish:
Acoustics
Mackerel Herring
0
20
40
60
80
100
18 38 70 120 200
Frequency (kHz)
Ec
ho
str
en
gth
0
10
20
30
40
50
60
70
80
90
18 38 70 120 200
Frequency (kHz)
Ec
ho
str
en
gth
Krill
0
1
2
3
4
5
18 38 70 120 200 364
Frequency (kHz)
Ec
ho
str
en
gth
Multifrequency
• Small pelagic fish
• Satellite
• Top predators
• Oceanography
• Phytoplankton
• Zooplankton
Some results - fish
• Small pelagic fish
o Sprat (assessment) o Lyme Bay (~30 kt)
o Bristol Channel -overwintering
juveniles (100 kt)
o Anchovy – in eastern part of
western Channel
o Sardine – along coast in survey
area
• 2013
o Sprat up
o Mackerel
Ichtyoplankton
Sardine spawning
larv
ae
2012 2013
eggs
Oceanography 2012 2013
MarineLife: Marine mammals and birds
Summary
• Rich species mix in coastal waters
• Habitat niche
• Importance of physical
environment
timing autumn bloom,
frontal areas
• Hotspots
• Population size (continued)
• Habitat
• Foodweb
NERC/Defra MERP project
Future work
