Anadromy and genetic relationships in remnant populations

of sea-run brook trout

A project sponsored by Trout Unlimited, Southeastern Massachusetts Chapter

Historically, anadromous brook trout were a common and valuable resource in the waters along southern New England’s coast.  These large and abundant fish were prized for angling and eating.  Overfishing and habitat loss has contributed to the decline of these native anadromous salmonids, particularly at the southern end of their range.  While many rivers in Canada still have healthy runs, populations in New England and on Long Island, closer to developed urban centers, have been lost or reduced significantly.  But while much is understood about sea-run brook trout in their northern range, few studies have focused on declining southern populations where their habitats and migratory behaviors are reportedly unique.  An assessment of anadromy and genetic relationships in southern New England populations would benefit several existing efforts by various government and conservation groups to restore remnant populations in the region, including TU’s efforts on the Quashnet and at Red Brook.  

The objective of this proposed project is to document anadromy (salt water migration) and determine genetic diversity among and between several remnant populations of sea-run brook trout in coastal waters of southern New England and Long Island.  In this study, scale and fin tissue will be sampled from brook trout in six regional streams and local hatcheries.  Chemical composition of scale tissue will be analyzed using mass spectrometry to identify marine specific signatures distinguishing anadromous from resident freshwater trout.  Polymorphism of microsatellite markers in DNA derived from fin tissue will be analyzed with laboratory techniques and software tools.  Genetic relatedness between anadromous and resident fish from the same stream, as well as between regional stream populations, and between wild and hatchery stocks will be quantitatively compared. 

Anadromous stocks of brook trout are currently indiscernible from the common freshwater resident stocks, so documentation of anadromy will help fisheries managers to prioritize populations for protection and to focus restoration effort where it is needed.  Understanding genetic relationships will help managers to prevent further impacts from indiscriminate stocking and will identify appropriate source populations to rebuild this valuable fishery and unique piece of natural heritage.

Results will be shared with resource managers and restoration groups through publication of peer reviewed journal articles as well as through workshops and publications sponsored by cooperating groups, including the Waquoit Bay National Estuarine Research Reserve, the Massachusetts Division of Fisheries and Wildlife, the New York Bureau of Fisheries and local chapters of Trout Unlimited.

Brendan Annett can be reached through Waquoit Bay National Estuarine Research Reserve.

(Written by Brendan Annett, June, 2004.  Brendan reports he's hoping to see some results by the fall...)