North Sea

Exploitation increased dramatically since the 1940s to the current state of heavy exploitation. Historical fisheries for herring collapsed in the 70s and were replaced by industrial fisheries for sandeel and Norway pout. Long-term trends (1980-2005) show that there have been significant fishing impacts with decreases in fish size and trophic level of landings. Since the early 90s fishing effort has been reduced considerably to halt the decline of important demersal stocks such as cod. The current state is characterized by low biomass of large longer-lived predatory fish, high biomass variability and a high proportion of overexploited stocks. This is due to the increase in small prey as large predators have declined, changes in the plankton and in the behaviour of the fishing industry.

by Julia Blanchard, Steven Mackinson
Table of Frequencies (percent)
Direction Fish size Trophic Level % Predators Life Span Biomass Stability % Sustainable Stocks
Fish size 0.117999 0.00 0.00 0.00 0.00 0.00
Trophic Level 0.00 0.649853 0.00 0.00 0.00 0.00
% Predators 0.00 0.00 0.651821 0.00 0.00 0.00
Life Span 0.00 0.00 0.00 0.268415 0.00 0.00
Biomass Stability 0.00 0.00 0.00 0.00 0.130164 0.00
% Sustainable Stocks 0.00 0.00 0.00 0.00 0.00 0.196232

Chla = Chlorophyll A (mg/m3)
SST = Sea Surface Temperature (°C)