Research

Genetic connectivity in open ocean environments

Large pelagic fishes, including tunas, marlins, swordfish, and some sharks, are predatory species that inhabit the world's open oceans. These fishes are often continuously distributed across broad geographic regions, and are capable of long distance migrations spanning hundreds to thousands of miles. Large pelagic fishes support commercial and recreational fisheries across the globe. However, many of these species are currently exploited at unsustainable levels of harvest, or are struggling to recover from historically high harvest rates.

My research on large pelagic fishes aims to understand mechanisms influencing genetic connectivity in environments conducive to high levels of gene flow, and how these mechanisms may be affected by changing conditions. Specifically, this work provides insights into the distribution of genetic diversity across space and time, constraints on gene flow among pelagic populations and species, and adaptation of pelagic populations to regional conditions. My research also provides practical information to regional fisheries management organizations to help improve management efforts for pelagic species.

Figure 1. Clusters corresponding with genetically distinct populations of striped marlin (Kajikia audax; A) and a single population of white marlin (Kajikia albida; B). These species inhabit the Indo-Pacific and Atlantic, respectively.

Genomic impacts of natural and anthropogenic stressors

Wild populations are exposed to wide-ranging stressors including disease, habitat loss, competition with non-native species, and changing environmental conditions. What is the impact of these stressors on genetic diversity, and what does this mean for the short- and long-term persistence of wild populations? I integrate environmental, ecological, and genomic datasets to comprehensively evaluate impacts of natural and anthropogenic stressors on wild populations.

Currently, I investigate these questions using brook trout (Salvelinus fontinalis), a salmonid native to the eastern United States and Great Lakes. Brook trout require pristine habitat characterized by cold, clean, and connected waterways, and massive declines in the abundance of this species in recent decades reflect degraded environmental conditions. I am using brook trout in the Lake Superior basin to understand the genomic impacts of physical barriers to connectivity, stocking hatchery-reared brook trout and non-native salmonids, and changing environmental conditions. My research provides practical information to guide mitigation efforts by regional resource managers and conservation groups.

Figure 2. Schematic of ecological and environmental variables potentially influencing genomic variation in Lake Superior basin brook trout (Salvelinus fontinalis).