Networks of biologically-connected marine protected areas need to be carefully planned, taking into account the open ocean migrations of marine fish larvae that take them from one home to another sometimes hundreds of kilometers away.
Research published today in the international journal Oecologia sheds new light on the dispersal of marine fish in their larval stages, important information for the effective design of marine protected areas (MPAs), a widely advocated conservation tool.
Using a novel genetic analysis, researchers at the University of Windsor, Canada, and the United Nations University's Canadian-based Institute for Water, Environment and Health (UNU-INWEH) studied dispersal and connectivity among populations of the bicolor damselfish -- a species common to Caribbean coral reefs and a convenient proxy for many coral reef fish species with similar biology, including a typical 30-day larval stage.
Using samples of newly settled juvenile fish from sites in Belize and Mexico, they traced the origins of hundreds of individual fish larvae back to putative source populations.
"This is the first time that genetic 'assignment tests' have been used to delineate the pattern of connectivity for a marine fish in a region of this size (approximately 6,000 square kilometers)," says lead author Derek Hogan of the University of Windsor, now at University of Wisconsin.
"We found that larvae of this species, on average, traveled 77 km from home in the 30-day larval period," says Dr. Hogan. "Although some fish remained close to home in the same period, some traveled almost 200 km - roughly the distance from New York City to Albany - an impressive feat for a larva about the size of a baby fingernail."
The scientists were surprised to find that patterns of larval dispersal among reefs changed from year to year, driven perhaps by changes in oceanographic currents or meteorological events.
"These results show
|Contact: Terry Collins|
United Nations University