CAMBRIDGE, MD (July 13, 2006) – A recent paper published in the scientific journal Estuaries and Coasts, has found that winter weather patterns are one of the key factors influencing the success of striped bass. Winter weather patterns that produced spring conditions with high freshwater discharge and low salinities increases the food concentration available to striped bass larvae.
Striped bass are highly migratory, inhabiting estuaries and oceans as adults but utilizing restricted nursery regions in tidal freshwater and low salinity regions. The numerous tributaries of the Chesapeake Bay form a complex nursery system that support the majority of striped bass commercial and recreational stocks. The spawning success of striped bass is related to several factors including the water quality, temperature, extent of habitat area, and food resources available for the striped bass hatchlings.
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E. affinis, Baltimore Inner Harbor. J. Adam Frederick, Maryland Sea Grant Extension Program |
Striped bass eggs hatch after 1-3 days and the larvae originally rely upon an egg yolk for approximately 2-5 days. After that period the larvae are approximately one tenth of inch and must find appropriate food. As predators striped bass larvae rely upon zooplankton populations. During wet winters and high spring flows an important zooplankton species, Eurytemora affinis, does extremely well and in previous studies has been shown to make up a large proportion of the larval diet.
Lead author Dr. David Kimmel of the University of Maryland Center for Environmental Science’ Horn Point Lab said, “This study shows a strong relationship between the winter conditions in the Bay’s watershed and zooplankton populations in the spring. It turns out that this particular species of zooplankton is one of the factors that affects spawning success of striped bass. Based on this study, we should now be able to develop short-term forecasts of the magnitude and composition of spring zooplankton populations.”
The research findings are based on reviewing weather patterns, zooplankton abundance, and a juvenile index of striped bass data from 1985 to 2000. During the dry winters (1985-1992) zooplankton abundances were low as well as striped bass juvenile index. During most wet years zooplankton abundances were high and the striped bass juvenile index was generally higher.
Fisheries biologist Dr. David Secor of the UMCES’ Chesapeake Biological Lab said, “While we knew there was a link between the cycles of wet and dry winters and the success of larval striped bass, the connection to climate patterns had not been made. This paper provides a broader predictive capability – linking climate change to striped bass production through the effect of climate on water quality and larval food resources.” He continued, “That understanding the links between climate, water quality and living resources are key to predicting future success and resiliency of striped bass which is an important keystone species in the Chesapeake Bay.”
Kimmel’s coauthors included UMCES’ Horn Point Lab colleagues Drs. David Miller and Michael Roman. |
