RESEARCH STUDY FINDS ANCESTRAL WILD BROOK
STILL INHABIT NEW JERSEY STREAMS
(08/17) TRENTON - Wild brook trout swimming in some of New Jersey’s waters are descendants of the native species that first appeared here more than 10,000 years ago, according to the results of a genetic-research study released today by Department of Environmental Protection Commissioner Lisa P. Jackson.
“The remarkable finding of ancestral brook trout in New Jersey’s streams is a testament to the importance of our strategies to protect water quality in our watersheds,” Commissioner Jackson said. “We will use the findings of this valuable research to further guide conservation of New Jersey’s wild brook trout and the natural ecosystems they depend on for survival.”
Wild brook trout populations maintain themselves in New Jersey’s streams through natural reproduction. Hatchery-reared brook trout stocked in high-quality streams can survive, reproduce and interbreed with wild trout. Ancestral or “heritage” brook trout, however, are wild fish that have not interbred and retained the original genetics of their native ancestors.
Although New Jersey ceased a century-old practice of stocking hatchery trout in some wild-trout waters in 1990 to protect the wild trout population, state biologists feared that heritage brook trout might have been lost to interbreeding. Further, secondary impacts of development over the years have impaired many of the cold, clear, highly oxygenated waters that wild trout need to survive, taking a toll on brook trout populations.
The DEP’s Division of Fish and Wildlife embarked on the research study to evaluate the genetic diversity and structure of New Jersey’s wild brook trout populations. The study included 22 wild-trout streams from four major watersheds, which still support wild trout populations: Delaware, Hudson, Passaic-Hackensack, and Raritan. Nineteen of those streams were thought to have high potential for the presence of heritage brook trout, and three were selected because of their known history of trout stocking.
Blood samples from 218 wild trout were collected from those streams and from 20 trout raised at the state’s Pequest Trout Hatchery, and DNA analysis was conducted.
The genetic analysis revealed the presence of heritage brook trout populations in 11 streams in two major river basins, the Passaic-Hackensack and the Raritan, and that each of the 22 wild brook trout populations studied have a unique genetic identity. The research revealed that the gene pool of at least one wild brook trout population (Cooley’s Brook in the Passaic-Hackensack watershed) has been affected presumably by interbreeding with hatchery-reared trout stocked before 1990. The analysis of samples from the remaining 10 streams were inconclusive as to genetic origin of those populations.
New Jersey’s only native trout species and the state’s official fish, brook trout colonized after the last glacial ice sheet receded more than 10,000 years ago. Today, wild brook trout inhabit more than 120 small streams cradled in the forested hills and mountains of north Jersey, and one stream in south Jersey.
Partial funding for the brook trout genetics study was made possible through natural-resource damages that the DEP’s Office of Natural Resource Restoration recovered from parties responsible for contamination and natural resource injuries at the GEMS Landfill in Gloucester County.
To review the research report, visit http://www.njfishandwildlife.com/bkt_genetics.htm