Estuarine and habitat-related differences in growth rates of young-of-the-year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) in three northeastern US estuaries

Instantaneous growth rates of young-of-the-year winter flounder Pseudopleur onectes americanus (Walbaum) (12.0-60.4 mm standard length, SL) and tautog Tautoga onitis (Linnaeus) (21.4-73.8 mm total length, TL) from three estuar ine systems in New Jersey (Great Bay-Little Egg Harbor and Navesink River) and Connecticut (Hammonasset River) were used in an attempt to assess the r elative quality of selected nominal habitats. A series of short-term field caging experiments were conducted during 1994 and 1995 in: macroalgae (prim arily, Ulva lactuca), eelgrass (Zostera marina), unvegetated areas adjacent to macroalgae and eelgrass and tidal creeks in Spartina dominated marsh. G rowth rates varied with habitat, estuary and year. Comparisons across nomin al habitats within and among estuaries did not show any one habitat with co nsistently higher growth, and growth was relatively independent of whether a habitat was vegetated or adjacent to vegetation. The growth rates of wint er flounder and tautog from the Hammonasset River were not different among habitats in either year of the study. In the Great Bay-Little Egg Harbor, b oth winter flounder and tautog had higher growth rates in macroalgae with g rowth in eelgrass varying significantly between years. Conversely, in the N avesink River both species had higher growth rates in eelgrass. Environment al changes associated with temperature and dissolved oxygen appeared to inf luence growth rates. Winter flounder growth rate and survival was depressed in tidal marsh creeks in the three estuaries and in vegetated macroalgae h abitats in the Navesink River where dissolved oxygen levels were often very low (<2 mg l(-1)) for extended periods. In summary, the growth rates of th e young-of-the-year of these two species varied temporally and were depende nt on the interaction or both the specific estuary and habitat in which the experiments took place. Further, habitat quality, as defined by relative g rowth rare, was difficult to evaluate because it can be variable and nomina l habitat designations are often not sufficient to define the boundaries of a species habitat requirements. Published by Elsevier Science B.V.