Bryan Taplin and Richard Pruell, environmental scientists at the EPA's Atlantic Laboratory in Narragansett, Rhode Island, are helping preserve North America's winter flounder, a fish popular for its texture and delicate flavor.
One key to protecting winter flounder populations, the scientists say, is to protect the habitats where young flounder develop and grow. The big question, however, is just what are those habitats? To find out, Taplin and Pruell need a little help from the fish itself.
The key to finding out where winter flounder spend their youth is contained deep within the fish's skull, in a small, white structure called an ear stone, or otolith. To fish, the otolith helps with balance and hearing, much like our own inner ear system. To scientists, the otolith is a recording device. "These ear stones are similar to an airplane's black box, they serve as a natural database of information," explains Taplin.
Each layer of the otolith is a snapshot of information that can be interpreted in much the same way that tree growth rings are read. Ear stones can be analyzed to reveal the age of a fish, the relative amounts of chemicals a fish came into contact with, and, Taplin and Pruell predict, which specific habitats a winter flounder lived in throughout its life.
In the first part of their study, Taplin and Pruell are attempting to identify otolith chemistry unique to winter flounder found living in specific "nursery" habitats close to shore. These habitats include eelgrass beds, areas with seaweed (also known as macroalgae), and unvegetated areas. They are also comparing coastal pond habitats with those from larger bay systems.
The growth patterns they identify will serve as "natal fingerprints" that the scientists can then look for in adult winter flounder, thereby determining what habitats these older fish utilized to survive to become adults.
As coastal development alters more and more of the landscape, it is critical to identify which habitats are most important for young winter flounder. Taplin and Pruell are just beginning their research, but the preliminary findings suggest we will soon be able to do just that. Armed with that information, local and state managers could prioritize areas for protection. This, in turn, should go a long way to rebuilding a healthy winter flounder population for commercial and recreational fishermen.