Plankton and fisheries

This chapter explores the dependence of fish on plankton and the relationship between plankton productivity and fisheries production. The dependence of fish production on plankton production is self-evident, since carbon fixation by photosynthetic phytoplankton forms the base of the marine food chain that leads to fish. Fisheries production is highest in areas of high plankton production, including upwelling areas (e.g. eastern boundary currents), fronts, and shelf seas with high nutrient supply. Marine mammals, seabirds, and fish that are capable of migrating over long distances often congregate to feed in these high productivity areas. However, it is generally not possible to infer fluctuations in annual fisheries yields from information on primary production, and even the average relationship for the nine areas together may be quite weak.