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Cod-tagging project to protect local cod

14 Jan 2014
Jeff Kneebone, a marine biologist with the Massachusetts Division of Marine Fisheries, releases a freshly-tagged Atlantic cod into Massachusetts Bay. Credit: John Clarke Russ

Jeff Kneebone, a marine biologist with the Massachusetts Division of Marine Fisheries, releases a freshly-tagged Atlantic cod into Massachusetts Bay. Credit: John Clarke Russ

Scientists and fishermen in Massachusetts are working together to gather data about cod behaviour, to better protect local cod during spawning season.

Local fishermen are now seeing cod only during their spawning season in the late autumn and early winter, whereas they used to be abundant for much of the year. Concerned commercial fishermen from the South Shore sought out scientists from The Nature Conservancy and other organisations to help them map out exactly when and where spawning occurs.

“We hope to provide these fish with protection while they’re vulnerable,” said local fisherman Frank Mirarchi. “The expectation is that we can provide discrete, small protected areas which will not be disruptive to fishing, while helping the cod stock to recover.”

Over the next few weeks, local fishermen, working with scientists, will hook spawning cod, implant electronic tags and then release the fish back into the sea.

Each electronic tag, once deployed, emits a coded sound roughly once a minute for up to six years, a signal that’s recorded whenever the fish passes within range of a network of receivers deployed on the sea floor. Each tag has a unique acoustic signature, allowing scientists to track individual fish using the more than three million pings each tag will emit over its lifetime.

This information allows researchers to visualise the behaviour of each fish while on the spawning grounds, and exactly when they leave which is needed for defining a seasonal closure and also to better understand spawning behaviour.

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Jeff Kneebone, a marine biologist with the Massachusetts Division of Marine Fisheries, releases a freshly-tagged Atlantic cod into Massachusetts Bay. Credit: John Clarke Russ

Image copyright © Mercator Media 2014, or image used with permission of the copyright holder.