Growth, Survival and Production in Young-of-Year Populations of Leiostomus xanthurus Lacépéde Residing in Tidal Creeks

Abstract

Growth, mortality, and production rates for spot,Leiostomus xanthurus Lacepede, were studied from January 1977 through August 1978 in tidal creeks of the Cape Fear estuary, North Carolina. Winter growth rates were low, averaging 0.14 and 0.16 mm per day in 1977 and 1978, respectively. Mortality rates were significantly higher in polyhaline marshes during 1977, however, similar rates were observed in oligohaline marshes in 1978. The difference is believed due to higher freshwater flows experienced in 1978, which apparently increased mortality rates upriver. Pooled monthly production estimates for all sampling sites combined yielded a value of 0.17 g per m2 (257 cal per m2). This figure is similar to those reported for spot collected in seagrass meadows in the vicinity of the Cape Fear estuary (Adams 1976). Because spot migrate offshore in the fall, this production also represents potential export of energy to the marine environment in the form of living biomass.