 | Juvenile winter flounder and sand shrimp
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Oceanographers study the
predator-prey relationshipWhile the stock of winter flounder as a whole is recovering from overexploitation, the populations in Narragansett Bay and in the Niantic River remain depleted. Elevated water temperature seems to be the culprit, elevating the metabolism and consumption rate of predators that feast on the juvenile flounder. One predator that seems to be having a negative impact on the survival of flounder is the sand shrimp.
URI Oceanography Professor Jeremy Collie has received a $40,000 grant from the National Oceanographic and Atmospheric Administration to study the effects of water temperature on predator-prey interaction in Narragansett Bay and the Niantic River and determine why the stock of winter flounder continues to decline.
The common sand shrimp lives in the Atlantic waters from Newfoundland to Florida and is an important component of estuarine systems, serving as both predator and prey. Elevated winter water temperature may increase the number of sand shrimp simply because warmer temperatures allow greater numbers to survive the winter.
Another factor concerns the migratory pattern of the sand shrimp, which return to the shallow waters of the Bay in late spring. Previously, juvenile flounder were able to grow to a body size that would prevent them from becoming a significant prey item for sand shrimp. But as water temperatures have increased, sand shrimp are moving into shallow waters earlier while juvenile flounder are still vulnerable. In addition, increased water temperature could directly influence the physiology of sand shrimp by enhancing metabolic activity and thus increasing their predation on juvenile winter flounder.
“Investigating the effects of changes in temperature on population dynamics is increasingly important given the anticipated effects of global warming on marine and estuarine systems,” said David Taylor, a doctoral student working with Collie. “Additionally, research identifying the influence of climatic variability on predator-prey relationships is critical for predicting the effects of changes in water quality on food web dynamics and the ability of juvenile flatfish to grow into adults.”
By Lisa Cugini
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