Publication Abstract

Seasonal variation in the diets of bluefish Pomatomus saltatrix (Pomatomidae) and striped weakfish Cynoscion guatucupa (Sciaenidae) in southern Brazil: implications of food partitioning

Seasonal variation in the diets ofbluefish Pomatomus saltatrix (Pomatomidae) and striped weakfish Cynoscion guatucupa(Sciaenidae) in southern Brazil: implications of food partitioning

F.M. Lucena, T. Vaske Jr., J.R. Ellis, J.R. and C.M. O'Brien

The stomach contents of 516 Pomatomus saltatrix and 506 Cynoscionguatucupa from southern Brazil were examined. Both species preyed primarily uponteleosts and crustaceans and occasionally squid. Seasonal variation in the diet wasrelated to prey availability in the area, confirming the opportunistic feeding behaviourof both species. During the summer, P. saltatrix preyed upon four prey species (Loligosanpaulensis, Artemesia longinaris, Mullus argentinae and Paralonchurusbrasiliensis), whereas in the autumn and winter Engraulis anchoita was thepredominant prey. C. guatucupa similarly preyed upon A. longinaris and P.brasiliensis during the summer, with juvenile C. guatucupa and E.anchoita also consumed. The latter species was an important dietary constituentduring other seasons, as were A. longinaris (autumn), Umbrina canosai(winter), Trachurus latami and euphausids (spring). Although P. saltatrix hada broader diet than C. guatucupa during the summer, the latter species had abroader diet overall. Diet breadths were lower from autumn to spring, due to thepredominance of E. anchoita in the diet of both species. This restricted dietresulted in significant intra- and inter-specific diet overlap during the winter but,because of the seasonal abundance of E. anchoita, the high levels of diet overlapdo not necessarily indicate competition.

Reference:

F.M. Lucena, T. Vaske Jr., J.R. Ellis, J.R. and C.M. O'Brien, 2000. Seasonal variation inthe diets of bluefish Pomatomus saltatrix (Pomatomidae) and striped weakfish Cynoscionguatucupa (Sciaenidae) in southern Brazil: implications of food partitioning.Environmental Biology of Fishes, 57(4): 423-434.

F.M. Lucena, T. Vaske Jr., J.R. Ellis* and C.M. O'Brien*

Environmental Biology of Fishes, 57(4): 423-434