Condition and feeding of American Plaice (Hippoglossoides platessoides) in the North Atlantic with emphasis on the Flemish Cap

Abstract

The seasonal, annual and geographical changes in the Relative Condition Factor (Kr) of a total of 24 410 individual American plaice (Hippoglossoides platessoides Fabricius) were analysed. These samples were collected in three areas of the North Atlantic (NAFO Division 3M and Div. 3LNO, and ICES Div. IIb) in commercial fishing and scientific surveys from 1992 to 2003. Condition presented significant variation in both sexes as far as area, season and year effects were concerned. Condition decreased greatly in Div. 3M, slightly increased in Div. IIb and it was quite constant in Div. 3LNO in the considered period for each area. Relative Condition Factor value showed a remarkable relation with the estimated biomass in Div. 3M. Females showed a better condition than males, and condition in the periods of spring and summer was lower than in the periods of autumn and winter for both sexes. Interannual variation in condition was more evident in small sized (immature) individuals. The spawning period corresponded with the peak of condition in females and with a decrease in males. Feeding intensity and condition were inversely related across season, however when the same period was studied across years they showed a similar pattern. Food and feeding of 8 543 individual American plaice from these three areas were examined. Feeding intensity was higher on the Flemish Cap (78%). The main prey in the composition of stomach contents for this area, were Ophiuroidea (56%), Hyperiidea (13%) and Pandalus borealis (8%). Changes in the main components of the diet were found in the last years. Feeding habits by size range and comparison with the other areas were also analysed.