Over recent years, brook trout, a species thought to have disappeared from Ohio, has been making a return due to reintroduction and ecosystem restoration efforts. 10,000 years ago brook trout colonized Ohio’s Lake Erie tributary streams. This genetically distinct population of fish is the only trout native to the inland waters of Ohio. However, by the 19th century, only two stream systems were suitable habitat and contained thriving trout populations.
Brook trout only survive in cold and clean water. They have a very low tolerance to pollutants and human disturbance. During the early 1990s, the Chagrin River, Grand River, and Rocky River watersheds were severely impacted by deforestation, agriculture, and residential development resulting in the loss of their pristine habitat and remaining brook trout populations.
As a result, Ohio Division of Natural Resources developed plans to address the rehabilitation and restoration of Ohio brook trout with local park systems, trout clubs, educators, and state and local agencies. The main objectives were to identify and protect native brook trout habitat, take an inventory of potential brook trout habitat, and implement reintroduction in suitable sites.
Stream Surveys:
Streams in the Lake Erie watershed were first surveyed for existing trout populations and evaluated for potential habitat for brook trout. This was done by collecting the temperature of the stream during mid-summer. If the water was less than 20 degrees Celsius, then the stream habitat and fish populations were evaluated. This was often done with the use of seines; however, they also utilized a backpack electrofishers on some occasions. The streams with cold water, good habitat, and presence of other fish species were considered possible sites for brook trout reintroduction.
Propagation:
The streams meeting these standards were then stocked with enough brook trout to develop a self-sustaining population. Brook Trout reach sexual maturity at age three, therefore, this would need to be done for about four years in order for the populations to be successful.
In order to preserve the genetic distinction of native Ohio brook trout, gametes from fish captured in the stream were taken back to hatcheries and raised until they were of approximately 40 mm. The releases often occurred at the beginning of April in the shallow water riffle and run habitat throughout the streams to avoid predation and allow for the best chance of survival of the population.
Population Monitoring:
In order to evaluate the successes and failures of this reintroduction, population monitoring surveys were completed in the years following the releases. This was done once the populations demonstrated evidence of natural reproduction. Similar to the stream surveys seines and electrofishers were used. If the seining survey captured less than five total brook trout an electrofisher was used to verify the population size.
Protection:
Like stated above, the brook trout is a very sensitive species and therefore are under constant threat for extirpation. In order to prevent this, habitat restoration, education of sportsmen and residents, and conservation agreements were implemented. However, ODNR could not accomplish this without the help from other organizations and the public. To facilitate these processes and communication, the Brook Trout Advisory Committee was developed. This committee was comprised of stakeholders in the protection of brook trout.
The site evaluations, hatchery propagation, and stream surveys were successful in the reintroduction of brook trout in 10 Northeast Ohio streams. However, the species is still considered threatened and conservation efforts have continued to be implemented.
References:
Burt, A. (2007, July 01). Brook Trout Reintroduction: Lake Erie Drainage, NE Ohio. Retrieved from http://www.tumadmen.org/assets/documents/ODNR%20Brook%20Trout%20Final%20 Report.pdf
Images:
https://www.geaugaparkdistrict.org/nrm/brooktrout.shtml
http://www.fondriest.com/news/ohio-brook-trout-sulphur-springs.ht