Stanley M. Warlen

Age And Growth Of Larvae And Spawning Time Of Atlantic Croaker In North Carollna

The age and growth of larval Atlantic croaker, Micropogonias undulatus, was determined from daily growth increments on their otoliths. Smaller and younger larvae were found offshore near probable spawning areas while larger and older larvae were found near shore and in the lower estuary. A Laird-Gompertz growth model, L(t) = 0.926 exp {2.876 [1-exp(-0.0428t)]}, described the growth of larvae to 62 days old. The agespecific growth rate, derived from this relationship, declined with fish age. Atlantic croaker spawned over a 5-month period from mid-September to late-February, with the...


A Recurrence Model For The Prediction Of DDT Flux In Atlantic Menhaden

A simple recurrence model is developed for the prediction of DDT flux through Atlantic menhaden (Brevoortia tyrannus). The DDT body burden in young-of-the-year menhaden at any time is equal to the body burden on the previous day plus the DDT accumulated on the current day minus the DDT turnover. Accumulation of DDT is simulated and compared with field observations. Estimations of DDT ingestion, assimilation, turnover, and egestion are made on both per fish and population bases. It is estimated that emigrating juvenile menhaden export 20 g DDT year -, from the Newport River estuary in North...