Download - ICES How to count fish for management
ICES provides advice on state, exploitation and management targets for fish stocks
How?
Information from fish
• Length
• Weight
• Age
Information on population trends: surveys
• Trawls• Acoustics• Plankton• TV
Research vessels & industry
Information from catch
• Amount• Location• Timing• Bycatch
From ports, log books & observers
How do we use this information?Take a stock of fish:
Every stock has underlying structure
Add fishing…
Mortality rate
Change in thenumbers at age
We also measure the catch
• Observed mortality rates
• Catches recorded
Equations and simulations are used to combine the information.
Also observations of trends in populationsfrom surveys.
This produces a stock assessment
North Sea herring
To provide the advice for next year’s catches
We project forward with our best knowledge(maturity, growth, recruits, impact of fishing gear, natural death etc) across a range of fishing scenarios.
Scenarios set out in management plans
All management plans in the ICES area are tested using simulations
Simulations of Atlantic mackerel multiannual management strategy at different fishing mortalities
Framework for advice
International agreements and policies:• UN Convention on the Law of the Sea (UNCLOS 1982) -MSY• UN Conference on Environment and Development (UNCED, 1992) -precautionary approach• UN Straddling Fish Stocks Agreement of 1995 (UNFSA 1995) - precautionary approach• Convention on Biological Diversity (UN CBD, 1992) - ecosystem approach• Johannesburg Declaration of the World Summit on Sustainable Development (WSSD UN 2002)-
ecosystem approach & MSY
National and regional legislation:including CFP, MSFD, Norwegian Marine Resources Act, Russian Federal Law on Fisheries, Icelandic Fisheries Management Act, Faroe Islands Fisheries Management Act
Reference pointsPrecautionary Approach
Populations need to be maintained within safe biological limits -Certain that reproductive success is not impaired
Reference pointsmaximum sustainable yield (MSY)
ICES interpretation of MSY is maximization of average long-term yield from sustainable stocks
Reference pointsmaximum sustainable yield (MSY)
Ecosystem Approach
Use of reference points: current and future
North Sea herring
State of the stocks North Sea overview