Environmental Continuity in Fluctuation of Fish Stocks in the North Atlantic Ocean, with Particular Reference to Atlantic Salmon

Abstract

Large masses of cold, low-salinity or warm, high-salinity water move with ocean currents in the North Atlantic Ocean, drastically changing the conditions for the biota and affecting the sizes of fish stocks. Oceanic conditions in the Barents Sea seem to be repeated in the Iceland Sea 2 to 3 years later. The sea temperatures in these areas fluctuate similarly with time lags of 2 and 3 years; the correlation coefficients are 0.63 and 0.62 for 2- and 3-year differences, respectively (P < 0.05). The abundance of stocks of Atlantic salmon Salmo salar in rivers in north Iceland show fluctuations similar to those of Atlantic salmon stocks in rivers on the Kola Peninsula in Russia 2 to 3 years earlier. Correlation coefficients of Atlantic salmon stock size in three rivers of the Kola Peninsula and the salmon catch in three rivers in north Iceland were 0.62 to 0.90 (P < 0.01). Similar trends were observed in recruitment and catch of Atlantic cod Gadus morhua and catch of capelin Mallotus villosus in these distant areas. We hypothesize that fish stocks in other areas of the North Atlantic Ocean show similar fluctuations in abundance with time differences based on the rate of movement of the ocean currents.