Most winter flounder populations found in the bays of Long Island, NY, are severely inbred as the result of overfishing, new research from the School of Marine and Atmospheric Sciences at Stony Brook University has found. The new research highlights a significant, and rarely acknowledged, problem with regard to overfishing — loss of genetic diversity. Overfishing also generally results in a reduction in body size amongst the species as a result of larger fish being caught more often.
Currently, inbreeding isn’t a factor that’s taken into consideration in marine fisheries management. This research is some of the first to investigate the occurrence of inbreeding in a marine fish. “The scientists extracted genomic DNA from the fins of 267 young of the year winter flounder caught over a period of several months in 2010 and 2011, and used 11 polymorphic microsatellite loci (molecular markers) to test for genetic diversity.”
The researchers found that there were less than 500 breeding-capable fish in each bay, which suggests that the spawning populations of this previously abundant fish are much smaller now than they were historically.
“While documented to occur in freshwater fish, inbreeding in marine fish is generally not a serious concern because of their perceived ability to move through larger areas to find mates and, historically anyway, their much larger population sizes making it unlikely they would spawn with relatives,” stated Shannon O’Leary, lead author and doctoral student at SBU. “Our research suggests that the possibility of inbreeding should be considered in the management of some commercially and recreationally exploited marine fish.”
“Inbreeding has been linked to lower survival and reproductive rates as well as lower resistance to disease and environmental stress, which could directly contribute to the failure of fish populations to recover from exploitation. However, since inbreeding has not been considered likely in marine fish, current fisheries management practices have been developed without incorporating its associated risks.”
“We are just beginning to realize that marine fish frequently exist as a series of smaller subpopulations as opposed to one large, well-mixed and widely distributed population,” stated Dr. Demian Chapman, leader of the research team, who is an assistant professor in the School of Marine and Atmospheric Science and assistant director for science at the Institute for Ocean Conservation Science at SBU. “The evidence of inbreeding we have found supports this new paradigm. The number of effective breeders in each bay is also alarmingly low and argues for strong fisheries management and habitat restoration initiatives to rebuild winter flounder populations in Long Island bays.”
The new research was just published online in the journal PLOS ONE.