MD - Large rockfish leave Chesapeake Bay to become ocean migrators; smaller fish remain

A new electronic tagging study of 100 Potomac River striped bass sheds light on rockfish migration in Chesapeake Bay and the Atlantic Coast. University of Maryland Center for Environmental Science researchers found that when rockfish reach 32 inches in length they leave Chesapeake Bay and become ocean migrators. Small fish stayed in the Bay had higher mortality rates than those that undertook ocean migrations.

"Knowing the size at which they leave, we can do improved management that is tailored better to commercial and recreational fishing sectors those related to catch and size limits," said study author and Professor Dave Secor of the University of Maryland Center for Environmental Science. "It allows us to bring different parts of the fishery into an assessment model to evaluate stock health and test how effective regulations will be."

Chesapeake Bay striped bass, also known as rockfish, (Morone saxatilis) were implanted with two-inch acoustic transmitters and their coastal shelf migrations recorded over a four-year period by telemetry receivers throughout the Mid-Atlantic shelf waters and southern New England. Researchers found that only large striped bass from the Chesapeake Bay migrate to ocean waters when they reach 32 inches in length, and smaller fish remain resident to the Chesapeake Bay, regardless of sex.

"By our best estimates they are in the Chesapeake Bay for 9 years, and when they reach 32 inches they head north," said Secor.

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