YY-Male Brook Trout as an Eradication Tool of Wild Brook Trout Populations in New Mexico

Duration

July 2018 - June 2021

Narrative

Brook Trout, native to northeastern North America, share some of the same resource requirements as other salmonids that inhabit cold high elevation streams. The species has invaded the western U.S. and is extirpating native fishes, especially when in sympatry with native trout. In New Mexico, native Rio Grande Cutthroat Trout (RGCT) have experienced a decline due to loss of habitat and competition from non-native trout. Viable removal options for non-native trout are currently limited to piscicides and manual removal. Piscicides are effective but costly and non-species specific. Manual removal can be species specific, but generally has a low success rate. In light of these management needs, recent development of the Trojan male (hereafter, referred to as MYY) Brook Trout offers a species specific and cost-effective method of eradicating invasive Brook Trout. MYY can only produce male offspring and will theoretically drive the wild Brook Trout population to 100% males and eventual eradication.
The goal of the proposed work will be to shift sex ratios of selected populations of wild Brook Trout toward all male fish and eventual extirpation. These populations of Brook Trout are of interest because they are sympatric with populations of RGCT, which are of conservation value due to low introgression and protection on private lands. In addition, the wild populations inhabit relatively short distances of stream (1-7 km), with few tributaries and barriers to prevent recurring invasion of wild Brook Trout. Our objectives going forward in 2018 will be to introduce MYY Brook Trout and conduct seasonal surveys to characterize survival and growth of young-of-year Brook Trout and the MYY Brook Trout. We are working closely with our State Cooperator, New Mexico Department of Game and Fish, to assess the utility of using MYY as efficient management tools for future conservation efforts of native fishes.