Although the behavior is not well known, brook trout that reside in coastal streams may spend part of their lives in salt water. Eventually these fish come back to fresh water to spawn, completing a life cycle called "anadromy".
Anadromous brook trout may leave fresh water streams and move into saltwater estuaries for a few months to more than a year. Typically, brookies migrate from fresh to saltwater as juvenile fish, feeding on abundant prey that is found in saltwater estuaries.
Research in two Maine streams with anadromous brook trout found that their migration from fresh to salt water occurred mainly from April through June. Their return to fresh water starts in May and can last until early August. When saltwater brook trout return to streams they are silvery in color. The unique coloration begins to fades after a few weeks in freshwater.
Populations of anadromous brook trout appear to be declining throughout their range. This decline is believed to be due to over fishing, habitat degradation and loss, in-stream barriers or predation. There has never been an intensive survey of Maine's anadromous brook trout populations, so their current status in Maine is uncertain.
According to Maine Inland Fisheries and Wildlife, a lack of information about these unique fish has prompted the agency to start a volunteer angling survey of coastal brook trout waters. Recruiting anglers to aid in this effort greatly increases our ability to gather data over a wide area. By taking a small sample of scales from brook trout caught in coastal rivers, chemical analysis will be able to tell scientists whether a trout is anadromous or "resident" (non-anadromous).
This information, when combined with a simple volunteer logbook detailing the amount of time spent fishing and the number of fish caught, will give MDIF&W valuable data for an initial assessment of anadromous brook trout populations in Maine.
Anglers that are interested in participating in Maine's Anadromous Brook Trout Angler Survey can contact Maine IF&W Fisheries Research Section: Merry Gallagher at (207) 941-4381, or email@example.com
source: Maine Inland Fisheries and Wildlife