Warmer oceans reduce dispersal of shellfish larvae
Warmer oceans reduce dispersal of shellfish larvae
mongabay.com
December 25, 2006
In a study published in the Dec. 25 Early Edition of Proceedings of the National Academy of Sciences (PNAS), scientists show they can predict how the distance marine larvae travel varies with ocean temperature. The say that the findings have important implications for the conservation and management of fish, shellfish and other marine species in oceans increasingly effected by climate change.
“Most marine life, including commercially important species, reproduces via larvae that drift far along ocean currents before returning to join adult populations,” explained a statement from the University of North Carolina at Chapel Hill (UNC), one of the institutions involved in the research. “The distance larvae travel before maturing, called dispersal, is directly linked to ocean temperature, the researchers found. For example, larvae from the same species travel far less in warmer waters than in colder waters.”
 Photo by Rhett Butler. The study found larvae that travel 62 miles at 53 degrees Fahrenheit would disperse only 46 miles at 59 degrees. |
“Temperature can alter the number and diversity of adult species in a certain area by changing where larvae end up,” said lead author Mary O’Connor, a graduate student in marine ecology at UNC. “It is important to understand how a fish population is replenished if we want to attempt to manage or conserve it.”
O’Connor and colleagues used data from 72 marine species to develop their dispersal model which forecasts how far larvae travel at a given temperature.
“We can apply this rule to animals without having to go out and measure every species,” O’Connor said. “Our general model gives us a powerful new way to study larval movement with knowledge about ocean temperature, which is much easier to come by. With models such as this, we can see what large-scale changes in ocean temperature may mean for adult populations.”
O’Connor says the results have important implications for commercial fisheries and conservation efforts.
“For many animals, the larval phase is the only chance for babies to get away from parents. Dispersal prevents inbreeding; for some species, this is a time to move from breeding ground to habitat where they’ll mature,” she said.
“In warmer waters, marine protected areas may need to be closer together than in colder water, since in warmer water dispersal distances tend to be shorter,” she added. “On the up side, shorter dispersal can mean greater survival because the larvae spend less time in the water, where they are at a high risk of death. On the down side, it could mean they won’t travel as far and may not make it to their juvenile habitat.”
This article is based on a news release from the University of North Carolina at Chapel Hill.