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Darryl W. Hondorp

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Sex determination of fish species is difficult to assess when sexual dimorphism and gametes are not apparent. For threatened and endangered fish species, noninvasive techniques are needed when determining sex to minimize stress and the potential for mortality. We evaluated the use of a portable ultrasound unit to determine sex of Lake Sturgeon Acipenser fulvescens in the field. Ultrasound images were collected from 9 yellow-egg (F2, F3), 32 black-egg (F4, F5), and 107 fully developed male (M2) Lake Sturgeon. Two readers accurately assigned sex to 88–96% of fish, but accuracy varied in relation to maturity stage. Black-egg females and fully developed males were correctly identified for 89–100% of the fish sampled,...
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Adult sea lamprey (Petromyzon marinus) abundance in Lake Erie has remained above targets set by fishery managers since 2005, possibly due to increased recruitment in the St. Clair-Detroit River System (SCDRS). Sea lamprey recruitment in the SCDRS poses an enormous challenge to sea lamprey control and assessment in Lake Erie because the SCDRS contains no dams to facilitate capture and discharge is at least an order of magnitude larger in the SCDRS than most other sea lamprey-producing tributaries in the Great Lakes. As a first step toward understanding population size, spatial distribution, and spawning habitat of adult sea lampreys in the SCDRS, we used acoustic telemetry to determine where sea lampreys ceased migration...
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Freshwater ecosystems provide many ecosystem services; however, they are often degraded as a result of human activity. To address ecosystem degradation in the Laurentian Great Lakes, Canada and the United States of America established the Great Lakes Water Quality Agreement (GLWQA). In 1987, 43 highly polluted and impacted areas were identified under the GLWQA as having one or more of 14 Beneficial Use Impairments (BUIs) to the physical and chemical habitat for fish, wildlife and humans, and were designated as Areas of Concern (AOC). Subnational jurisdictions combined with local stakeholders, with support from federal governments, developed plans to remediate and restore these sites. Biotelemetry (the tracking of...
Categories: Publication; Types: Citation; Tags: Environmental Management
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Population structure, distribution, abundance, and dispersal arguably underpin the entire field of animal ecology, with consequences for regional species persistence, and provision of ecosystem services. Divergent migration behaviours among individuals or among populations is an important aspect of the ecology of highly-mobile animals, allowing populations to exploit spatially- or temporally-distributed food and space resources.This study investigated the spatial ecology of lake sturgeon (Acipenser fulvescens) within the barrier free Huron-Erie Corridor (HEC), which connects Lake Huron and Lake Erie of the North American Laurentian Great Lakes.Over six years (2011 – 2016), movements of 268 lake sturgeon in the HEC...
Categories: Publication; Types: Citation; Tags: Journal of Animal Ecology
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The USGS Great Lakes Science Center (GLSC) conducted acoustic and midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2013. The 2013 survey was conducted during September and October and included transects in Lake Huron’s main basin, Georgian Bay, and North Channel. Pelagic fish density was 1,033 fish/ha in 2013 and increased 62% over the 2012 estimate. Total biomass in 2013 (6.07 kg/ha) was similar to the 2012 estimate (6.97 kg/ha). Mean numeric density of alewife Alosa pseudoharengus was substantially greater in 2013 than in 2012, but the 2013 estimate has low precision. Age-0 rainbow smelt Osmerus mordax abundance increased from 2012, whereas age-1+ rainbow smelt decreased. Age-0 bloater...
Categories: Publication; Types: Citation
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