The Ichthyoplankton of Cape Cod Bay

Abstract

Ichthyoplankton sampling in Cape Cod Bay and in the vicinity of the Pilgrim Power Station yielded 60 species representing 34 families. Larval collections from Cape Cod Bay were numerically dominated by sand lance Ammodytes sp. over the 1974–1976 period. Based on the distribution of eggs and/or larvae, American plaice (Hippoglossoides platessoides), pollock (Pollachius virens), and Atlantic herring (Clupea harengus harengus) appeared to spawn primarily outside the Bay, their early developmental stages then drifting into the Bay with prevailing currents. Silver hake (Merluccius bilinearis), winter flounder (Pseudopleuronectes americanus), Sand lance, WindOwpane (Scophthalmus aquosus), Atlantic menhaden (Brevoortia tyrannus), and radiated Shanny (Ulvaria subbifurcata) clearly spawned within the Bay and displayed definite localized concentrations. The role of Cape Cod as a faunal barrier was examined by comparing Cape Cod Bay ichthyoplankton collections with concurrent collections from Block Island Sound. Results of more detailed study near the Pilgrim Power Station indicated that sampling stations defining the northwest sector of Cape Cod Bay formed a coherent group distinct from a more offshore group. Larval winter flounder densities were examined in detail in this northwest sector and in a nearby spawning area, Plymouth Harbor-Duxbury Bay. Evidence suggested that larval flounder flushed from this estuary had a higher probability of drifting toward the plant on spring tides than on neap tides. Studies directly adjacent to the power station compared relative abundance in the discharge canal and Cape Cod Bay.KeywordsSand LanceAtlantic MenhadenFishery BulletinScomber ScombrusPollachius VirensThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.