Consumption, Selectivity, and Use of Zooplankton by Larval Striped Bass and White Perch in a Seasonally Pulsed Estuary

Abstract

Many estuaries exhibit seasonal pulses of phytoplankton and /ooplankton production. Larval fishes that co-occur with these "blooms" should be at a growth and survival advantage compared with larvae that occur before or after the bloom, although this has been difficult to observe in many systems. We tested this potential advantage for larval (< 10 nun notochord length) striped bass Morone suxatilis and while perch M. americana in the Hudson River by examining consumption and feeding seleclivities with respect to zooplankton blooms. The cladoceran Bosmina lungirostris and large copepodite and adult copepods together composed 97.4% and 90.9% of larval striped bass and white perch diets, respectively. Peak consumption rates of Bosmina coincided with the bloom, whereas copepod consumption rates continued to increase throughout the sampling period. Selectivity for copepods was inversely related to selectivity for Bosmina and was high, except at those sites and times when Bosmina densities exceeded 14 animals/L. Per capita energy consumption was highest (0.75 and 0.39 J/individual for striped bass and white perch, respectively) after the bloom period, but specific consumption (energy consumed/nig wet weight fish) during and after the bloom were similar (2.39 versus 2.35 J/mg dry weight during the bloom versus after the bloom for striped bass and 2.58 versus 2.63 J/mg for white perch). Our energetics analyses indicate that different-si/ed fish experience different benefit-cost (consumption benefit : respiration cost) ratios, but strong trends exist with respect to the zooplankton bloom. Prcbloom cohorts have the least available food and lowest metabolic costs (respiration). Postbloom cohorts have both high consumption and respiration rates due to increased temperatures. Cohorts coincident with the bloom have moderately high specific consumption rates and lower metabolic costs relative to late cohorts. We conclude that larval cohorts coincident with the bloom possess an energetic advantage relative to early cohorts but not relative to late cohorts.

Recruitment of striped bass in Chesapeake Bay: spatial and temporal environmental variability and availability of zooplankton prey

“…Campfield (2004) also reported higher consumption of B. longirostris by striped bass larvae up-river of the salt front and ETM in the Patuxent River, while larvae downriver consumed mostly E. affinis. In the Hudson River, Bosmina freyi was the dominant food of larvae near the freshwater-salt water interface, where concentrations exceeded 100 000 prey m -3 (Limburg et al 1997). …”

“…Inter-annual and spatial variability in distributions of zooplankton were analyzed in the upper bay. Most analyses were on 2 dominant prey of striped bass larvae, the calanoid copepod Eurytemora afffinis and the cladoceran Bosmina longirostris (Beaven & Mihursky 1980, Limburg et al 1997, Campfield 2005. Additionally, spatial (1996, 1998, 1999, 2001 to 2003) and temporal (1993 to 2002) patterns in the combined concentrations of these taxa were analyzed and compared to minimum prey thresholds for striped bass larvae.…”

“…In the Hudson River, B. longirostris also blooms predictably in late May to mid-June, when its concentration surges from 100 to 100 000 ind. m -3 and striped bass larvae exhibit positive selectivity for this important prey (Limburg et al 1997). In the Patuxent River, B. longirostris is second only to Eurytemora affinis in importance as prey, although it is not positively selected by striped bass larvae (Campfield 2004).…”

Responses to the Foraging/Predation Risk Trade-Off and Individual Variability in Population-Level Fitness Correlates

“…Many fishes (e.g., [28,30,[34][35][36] and invertebrates [37] use highly productive estuaries opportunistically to exploit resource availability often as juveniles. Smaller estuarine-opportunist fishes are particularly at risk of predation (e.g., [28,[38][39][40]), and risk for estuarineopportunist fishes can be greater in estuaries than in stream ISRN Ecology 3 habitats [9].…”

Microhabitat-scale influences of resources and refuge on habitat selection by an estuarine opportunist fish

“…Schelske & Odum 1962), estuaries are often vital rearing habitats for marine and freshwater fishes (e.g. Kneib 1984, Sogard 1992, Kneib & Knowlton 1995, Gray et al 1996, Limburg et al 1997. Sogard (1992) suggests that rapid growth, providing a selective advantage by increasing both survival and fecundity, is key to the utilization of estuaries as nurseries for fishes.…”