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

Abstract

Causes of recruitment variability in young-of-the-year (YOY) striped bass Morone saxatilis from Chesapeake Bay were investigated based on (1) surveys from 2001 to 2003 to document spatio-temporal variability in abundance of larval striped bass, zooplankton prey, and feeding success of larvae; (2) a synthetic analysis (1996, 1998, 1999, 2001 to 2003) to describe how environmental factors and prey affect recruitment success; and (3) a 10 yr analysis (1993 to 2002) of inter-annual differences in spatial and temporal patterns of copepods and cladocera eaten by striped bass larvae. Striped bass YOY recruitment levels varied >11-fold in the 6 years examined. In those years, mean daily freshwater flows from the Susquehanna River to the bay in March and April varied > 2-fold and controlled distribution and apparent survival of striped bass larvae. Strong recruitments of YOY striped bass were associated with matches in space and time of larval striped bass and high concentrations of zooplankton prey, especially the copepod Eurytemora affinis and cladoceran Bosmina longirostris. The strongest year classes (1996, 2003) were produced in years of high freshwater flow, characterized by a high abundance of feeding-stage larvae and a spatio-temporal match between peak abundance of larvae and zooplankton prey. Enhanced feeding opportunities were most pronounced in high freshwater-flow years (1996, 1998, 2003), when larvae and zooplankton prey were strongly associated with, and apparently retained near, the estuarine turbidity maximum. First-feeding larvae fed more successfully in a high-flow year (2003; prey incidence 91%) than in a drier year (2001; prey incidence 35%). A regression model that may have forecasting potential was developed to describe recruitment of YOY striped bass for the years from 1985 to 2006. The model includes spring freshwater flow and air temperatures to predict age-0 striped bass recruitment strength (R 2 = 0.65). Flow and temperature control environmental and hydrographic conditions that strongly influence spatio-temporal overlap of larval striped bass and zooplankton. The model provided accurate recruitment forecasts for 2007 and 2009, but was less successful in 2008, a year of exceptionally low recruitment. KEY WORDS: Chesapeake Bay · Striped bass · Recruitment variability · Larval fish · Zooplankton · Trophodynamics · Biophysical interactions Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 409: [213][214][215][216][217][218][219][220][221][222][223][224][225][226][227][228] 2010 leading to higher larval growth rates and increased larval survival (Houde 2008).Spatial variability in the prey available to larvae, while not explicitly formalized in critical period and match-mismatch hypotheses, is recognized as a determinant of growth and survival. Feeding conditions of larval fish across mesoscale (>1 to 100 km) gradients in prey concentrations are often attributable to prevailing circulation patterns, frontal features, and interacting spa...

Top-down control by micro- and mesozooplankton on winter dinoflagellate blooms of Heterocapsa rotundata

“…In spring 2014, when water temperatures increased, the Eurytemora carolleeae populations increased (data not shown) and probably grazed the H. rotundata bloom. E. carolleeae peaks in abundance in late March and April in the Chesapeake Bay region (Kimmel & Roman 2004, North & Houde 2004, Martino & Houde 2010. Wet winters have been shown to result in high abundances and wide distribution of the copepod E. carolleeae in spring in Chesapeake Bay (Kimmel et al 2006).…”

“…High abundances and the timing of the peak abundance of E. carolleeae are correlated with striped bass Morone saxatalis larval recruitment in spring (Shoji et al 2005, Martino & Houde 2010. Timing of the bloom, copepod population development, and fish spawning will all affect the trophic transfer between winter−spring dinoflagellate blooms and larval fish.…”

Severe droughts reduce estuarine primary productivity with cascading effects on higher trophic levels

“…Abnormally low mesozooplankton abundances were noted in the NRE during summers of 2008and 2009. Similarly, Reaugh et al (2007 suggesting that lack of food availability (i.e., zooplankton) coupled with seasonal hypoxia affected fish health and population dynamics (Baptista et al 2010;Martino and Houde 2010). In another example, Baptista et al (2010) observed dramatic reductions in the biomass of estuarine resident and nonresident but estuarine-dependent fish species in a European estuary during a severe drought.…”

“…Although droughts represent more of an acute climatic feature as opposed to the abovementioned chronic changes in oceanic condition, our results show that droughts can still elicit seasonal to multiannual reductions in planktonic biomass and likewise negatively affect resident fish populations. Further, considering that the estuarine-dwelling phase of many commercial fish species may be critically dependent on one particular season (Able and Fahay 1998), it is tempting to speculate that a single drought could have prolonged negative consequences on estuarine-dependent fish species if larval or juvenile growth is hampered (Baptista et al 2010;Martino and Houde 2010). The ecological ramifications of a predicted increase in drought frequency and intensity as a result of ongoing climate change are indeed worrisome.…”

La diversité, la répartition et l’écologie du complexe d’espèces cryptiques Euytemora affinis, dans la zone d’alevinage de l’estuaire moyen du Saint-Laurent

“…Pauly et collab., 1998;Frederiksen et collab., 2006). Dans les estuaires, bien que les communautés zooplanctoniques soient très productives, elles sont caractérisées par une diversité d'espèces relativement faible, mais possédant une importance capitale pour les sites d'alevinage d'un grand nombre d'espèces de poissons (Vincent et Dodson, 1999;Cloern, 2007;Martino et Houde, 2010). Parmi les espèces de copépodes estuariens écologiquement importantes, le complexe d'espèces cryptiques Eurytemora affinis (figure 1) domine en biomasse la communauté zooplanctonique dans la plupart des estuaires de l'hémisphère nord (Lee, 2000;Winkler et collab., 2003;Tackx et collab., 2004;David et collab., 2007;Devreker et collab., 2010).…”