Effect of prey abundance and size on the growth and survival of larval fish: an experimental study employing large volume enclosures

Abstract

We examined the effect of natural variations in the concentration and size composition of plankton in coastal waters on the growth and survival of recently hatched larval capelin Mallotus villosus. Known numbers of larvae were stocked into 4 m3 j n sjtu enclosures, containing plankton communities whose size composihon and total particle concentration mirrored those occurnng naturally dunng times when the nearshore waters were alternately dominated by deep upwelled waters, and by warmer surface waters. Daily growth of larvae was unrelated to total plankton concentrahon, but strongly correlated with the concentrahon of plankton in the 40 to 51 pm (esd) size range. Daily mortality was negatively correlated with concentrations of plankton <81 pm (esd). This correlation was strongest with prey in the 32 to 40 pm and 40 to 51 pm (esd) size classes. The in situ concentration of plankton in the optimum size range for growth and survival was temporally dynamic and strongly influenced by wind-driven water mass exchange. The relevance of these findings to previous studies of the effect of prey concentration on growth and survival in larval fishes is discussed.

Growth and mortality in successive cohorts of fish larvae within an estuarine nursery

“…For example, Cowan & Houde (1990) observed mean daily specific growth and mortality rates of 0.20 and 0.15, respectively for bay anchovy Anchoa mitchilli larvae held in mesocosms suspended on a floating platform in Chesapeake Bay. Growth rates of capelin Mallotus villosus larvae reared in enclosures at ambient conditions in the Gulf of St. Lawrence were similar to those estimated for natural populations (Frank & Leggett 1986). The highest mean growth rate in the present study (G = 0.143) was less than estimated field growth rates (Kneib 1987) and only half that of F. heteroclitus larvae reared in the laboratory on an unrestricted ration (Kneib & Parker 1991).…”

“…However, unlike natural cohorts of F. heteroclitus larvae, in which usually fewer than 5% survived for 3 d after hatching (author's unpubl, data), mortality within the experimental cohorts was low and 20 to 90 % of the larvae survived for 2 wk in the enclosures. The high survival of larvae in this experiment was probably due to the exclusion of predators because mortality rates of fish larvae in enclosure experiments often are very sensitive to the presence or absence of predators (0iestad 1982, Frank & Leggett 1986, Cowan & Houde 1990. Because of the low mortality in enclosed cohorts, the larvae in this experiment probably were maintained at densities higher than those experienced in the natural population, even though initial stocking density was low relative to many natural peaks in hatchling density.…”

Spatial distribution and abundance of larval and juvenile fish, chlorophyll and macrozooplankton around the Mississippi River discharge plume, and the role of the plume in fish recruitment

“…Although we recognize that zooplankton biomass is an imperfect measure of larval fish food (Frank & Leggett 1986, Frank 1988, zooplankton concentrations in the frontal waters probably act to promote the cooccurring high ichthyoplankton concentrations. Some larval and small juvenile fishes found in the same neuston samples (e. g. Caranx crysos, Thunnus atlanticus, T. albacares, and Euthynnus alletteratus 5 20 mm SL) utilize macrozooplankton as prey (Finucane et al in press, Naughton et al unpubl.).…”

Plankton dynamics and larval herring growth, drift and survival in a frontal area

“…Despite the numerous theories relating food availability, larval survival and herring recruitment, evidence from nature of food limitation and its possible effects on fish larval growth and survival is limited (e.g. Frank & Leggett 1986).…”