Recruitment of young-of-the-year bluefish Pomatomus saltatrix to the New York Bight: variation in abundance and growth of spring- and summer-spawned cohorts

The bluef~sh Pomatomus saltatnx spawns offshore In cont~nental shelf waters and juven ~l e s mlgrate to near-shore or estuanne waters dunng t h e ~r flrst growlng season In estuanes of the New York Blght d u r ~n g 1987 and 1988 young-of-the-year bluef~sh appeared in 2 d~screte slze groups Otol~th analyses confirmed that the 2 groups originated from d ~s t ~n c t sprlng and summer spawnlng penods The spnng-spawned cohort flrst recruited to estuanes In early to m ~d -J u n e .whereas the summer-spawned cohort f~rst recru~ted In m ~d d l e to late August In contrast w ~t h prevlous years when only spnng-spawned f ~s h were abundant the overall abundance of s p n n g vs summer cohorts was s ~m ~l a r There were however, signlf~cant d~fferences In abundance among bays that depended on cohort Much of t h ~s v a r ~a t ~o n in abundance 1s probabl\ caused by vanation in advect~ve transport of larvae from spawnlng grounds to estuanes Growth patterns dlffered substant~ally between the 2 cohorts Spr~ng-spawned bluef~sh grew slower than summer-spawned blueflsh d u r ~n g the pre-recruitment oceanlc phase of the early llfe hlstory perhaps because the11 northward transport causes them to encounter lower temperatures d u r ~n g the larval p e r ~o d Both cohorts grow r a p ~d l y after estuanne recru~tment but spring-spawned blueflsh are much larger than summer-spawned bluef~sh at the onset of fall m~gratlon Overall year-class strength of bluef~sh along the US mid-Atlant~c coast IS a funct~on of the c o m b ~n e d recru~tment success of the sprlng and summel cohorts