Trophic interactions of chaetognaths, larval fish, and zooplankton in the South Atlantic Bight

Chaetognaths are highly abundant carnivores in manne environments, and feed both on flsh larvae and on the same foods as flsh larvae We assessed predation by chaetognaths on wlnterspawned flsh larvae and on the planktonic food of fish larvae in February 1992, December 1992, and February 1993 off the southeastern U S coast Feeding rates of chaetognaths were calculated from gut content analysis and experimentally determined digestion rates, and combined with estimates of In sltu denslt~es of predators and prey Chaetognath and larval fish dlstnbutlons overlapped temporally and spatially on all dates Densities of chaetognaths averaged 10 to 67 m and f ~s h larvae averaged 0 1 to 1 8 m-3 Only 1 flsh larva was found in 6718 chaetognath guts e v a m ~n e d Effects of chaetognath predation on the abundant s ~n a l l prey consumed by the small fish larvae present In December 1992 and Febluary 1993 were n e g l ~g ~b l e (0 3 to 0 7 % consumed d ') In February 1992, however, chaetognaths consumed up to 4 4 % d of standing stocks of large copepods that also were prey of the large fish larvae present on that date We conclude that chaetognaths were not Important predators ot flsh larvae during t h ~s study, but may, at times, consume substantial amounts of the copepod populatlons which are shared by fish larvae