Publications

Lake whitefish Coregonus clupeaformis abundance has declined throughout most of the Laurentian Great Lakes in North America for two decades. Current management strategies in Lake Erie assume that there is a single stock of lake whitefish that spawns in the West Basin. There is documented lake whitefish spawning activity throughout the lake, leading to questions about locally adapted...

Blue Catfish Ictalurus furcatus were first introduced to Virginia tributaries of the Chesapeake Bay in the 1970s and have greatly expanded in population size and distribution, prompting ecological and economic concerns. This study investigates the diet and trophic ecology of invasive Blue Catfish in tidal, low-salinity reaches of the Nanticoke River and Marshyhope Creek, on the...

Introduction: Arctic Grayling Thymallus arcticus were extirpated from Michigan in 1936. Their demise was caused by over-fishing, habitat destruction from large-scale logging, and Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta. Subsequently, Brook and Brown trout have become the dominant salmonid species in Michigan streams. Past attempts to restore Grayling to Michigan...

Globally, fish populations that rely on rivers are being fragmented by in-stream barriers, but it is unclear how pervasive any negative population responses to fragmentation are. We developed a modeling framework for estimating density responses of fishes upstream and downstream of in-stream barriers and applied it to learn how low-head dams have influenced fish assemblages in 24 Great...

A comprehensive understanding of life history is vital to successful species conservation and management. When different life history stages are accompanied by considerable morphological or cryptic variation, such as the egg and larval phases exhibited by most fishes, genomic tools are essential for identifying species so that early-life ecology questions can be studied. Genotyping-in...

Sculpins play a critical mid-trophic role in lacustrine food webs, converting production by benthic and migrating pelagic invertebrates into biomass available to higher trophic levels. Although sculpin diets and habitat choices are relatively well described, much less is known about their in situ behavior which governs trophic interactions and, in part, prey behavior. We measured the...

Conservation translocations are undertaken to increase the viability of imperiled organisms and/or restore ecosystem functions or processes. A key step in the conservation translocation process is to decide which source or founder population is most likely to lead to translocation success. Existing guidance to inform this decision includes a variety of considerations, but few documents...

Understanding the thermal habitat use of fish populations is vital for effective rehabilitation or management, particularly in the face of climate change, given limited thermal tolerances of some species. In Lake Erie, lake trout (Salvelinus namaycush) rehabilitation efforts by means of stocking have been ongoing for four decades. However, high water temperatures and lengthening periods...

Multi-jurisdictional management of adult lake sturgeon (Acipenser fulvescens) requires characterizing seasonal dynamics of their spatial distributions. Despite decades of research into lake sturgeon movement ecology, system-wide spatiotemporal behavior remains poorly understood in large lakes, particularly those with metapopulations differentiated by spawning river or migratory...

Otoliths are useful tools to estimate daily age, growth, and ontogenetic shifts in the early life stages of fish, providing information to support management efforts. Little effort, however, has gone into the examination of pre-hatch increment development. To assess variation in pre-hatch otolith size and increment formation, lake whitefish (Coregonus clupeaformis) sagittal otoliths were...

The U. S. Geological Survey-Great Lakes Science Center has monitored annual changes in the offshore (depth > 9m) prey fish community of Lake Huron since 1976. Assessment of prey fish populations in Lake Huron is based on a bottom trawl survey that targets demersal species (i.e., those predominantly or intermittently associated with the lake bottom) and an acoustic-midwater trawl survey...

Native freshwater mussels (family Unionidae) are in decline globally, including in the Laurentian Great Lakes. Glochidia, the parasitic larvae of unionid mussels, typically attach to sub-adult and adult fishes. Attachment of glochidia to larval fishes is more rare, and a lack of documentation exists on glochidial attachment on fish in the Great Lakes in general. We document the...