The ICES GLOBEC CCC programme completed it's synthesis activities in 2009 coming to an end at the same time as GLOBEC. The results and achievements of the programme are described as follows:
Cod stocks have generally declined over the past twenty years and landings fell from about 1.6 million tons in 1980 to just over half that in 2000. Climate change probably played a part in this decline for some stocks, but the overwhelming cause was excessive levels of fishing. Productivity and distribution of cod has been affected by environmental variability, with major consequences for recovery rates of depleted stocks.
The decline in cod stocks was steepest in the NW Atlantic, where landings in 2000 were 10% of their 1980 level and most fisheries remain closed.In many of these stocks individual growth rates declined from the early 1980s onward and condition of individual fish was also poor, so that mean weights at age fell by 50% or more. Poor condition contributed to lowering of recruitment rates, while natural mortality increased. The consequence of these changes, which are due in part to environmental variability and climate change, is that the productivity of some stocks has declined to the point where they are unlikely to recover even if the ban on fishing continues.
In the NE Atlantic the changes are less adverse. From 1980 to 2000 landings dropped by 50%, but in NEAFC Region 1 the decline was only 28%. Recruitment rates have fallen at the warm end of the species range, around the British Isles, but growth rates remain high and there is no evidence to date of increased natural mortality, such as has been observed in the NW Atlantic.
Information about the effects of climate on the processes which govern production (growth, maturation, egg production, transport during early life, survival and natural mortality) can be used in appraising the management options for sustainable fisheries. The development of methods for doing so has been an ongoing theme of the programme. Most of the processes have been the subject of workshops and theme sessions over the past few years, for example a workshop on Transport Processes in 2002 evaluated the effects of variations in transport during early life on subsequent recruitment and examined the coupling of circulation models with early life history models to determine the physical and biological processes responsible for the transport or retention of cod larvae. Cod eggs and larvae travel up to 1600 km during the pelagic stage, but greater distance does not lead to greater variability in survival and recruitment. The workshop is being followed up with a Theme Session in 2003 which will hear about further coupled modelling to explore survival and the transport between stocks. The results will be published as an ICES Cooperative Research Report.
Talks at the Session on Comparative studies of North Atlantic ecosystems at the 2nd Open Science meeting in Qingdao dealt with the response of plankton and fish to climate forcing and the effects of food and environmental limitations on growth production of cod. An ICES Workshop and Theme Session on cod growth provided much new information about the role of size selective fishing, food availability, environment and genetics in determining the changing growth patterns. (ICES Cooperative Research Report 252).