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CONFERENCE SCHEDULE UPDATES & CHANGES: As a result of the prolonged government shutdown, we experienced a number of cancellations and changes to the schedule. Cancellations and changes are listed here (as of January 26, 2019). 
Other - Diet [clear filter]
Tuesday, January 29

11:00am EST

(WILDLIFE: MAMMALS) Using Stable Isotope Analysis to Evaluate the Diet of the North American River Otter Throughout Ohio
AUTHORS: Sara Adamczak, The Ohio State University; Anne Wiley, The University of Akron; Mažeika Sullivan, The Ohio State University; Stanley Gehrt, The Ohio State University

ABSTRACT: The North American river otter (Lontra canadensis) is an apex riverine predator that is adapted to hunting in the water. This lifestyle results in a diet focused on aquatic and semi-aquatic species.  We sought to determine river otter diet composition and trophic level using stable isotope analysis. Understanding diet and trophic level provides insight into how river otters might influence community dynamics and potentially reveal important prey species for river otters in various riverine systems. We collected tissue, whisker and nail samples collected from 108 river otters across Ohio during 2017-2018. We used these samples to estimate the ratios d<sup>15</sup>N and d<sup>13</sup>C, comparing river otter values to those of potential prey items. The d<sup>15</sup>N measurements serve as indicators of a consumer's trophic level, whereas d<sup>13</sup>C values are used to determine carbon sources in a trophic network. Our preliminary analyses revealed a higher d<sup>15</sup>N for males (mean = 14.58) than females (mean = 13.97), suggesting that male otters tend to feed at a slightly higher trophic level than female river otters. The trophic level of juvenile river otters (15N = 14.02) was the same as adults (= 2 years old; d<sup>15</sup>N = 14.01); possibly a result of juveniles mostly feeding from their mothers until weaning. Yearling river otters (1-2 years old) appeared to feed at a higher trophic level than adults. This age difference may be a result of younger individuals feeding at multiple trophic levels compared to adults. The feeding habits of younger individuals, and consequently their trophic level, will often change over time. Perch, sunfish, and crayfish were found the preferred prey species across all otter age classes. These results support the idea of stable isotopes as a useful tool when examining river otter ecology, providing insight on river otter dietary sources, as well as their trophic positioning.

Tuesday January 29, 2019 11:00am - 11:20am EST

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  • Main Agenda Item
  • Poster
  • S01: Using Standardized Assessments to Evaluate Harvest Regulations: Advancing Science-Based Fisheries Management
  • S02: Eastern Massasauga Conservation - Management - Recovery
  • S03: Application of environmental DNA-based tools for aquatic invasive species monitoring and management
  • S04: Great Lakes Trophic Structure: Innovations and ongoing studies of predatory fishes
  • S05: Migratory wildlife collisions with manmade structures: monitoring - prevention - patterns from collision data
  • S06: Considering New Paradigms in the Management of Beaver - Trout - Riparian Habitats
  • S07: Use of Acoustic Telemetry to Inform Fisheries Management Across Midwestern US and Canada
  • S08: Science in service to wetlands conservation and wildlife management in the lower Great Lakes region: history - status - state of the art
  • S09: Carbon Dioxide As An Aquatic Resource Management Tool
  • S10: The Ohio Biodiversity Conservation Partnership: An Innovative University-State Agency Partnership for Conservation in Ohio
  • S11: Dreissenid Mussels: Advancements in control - detection - management - biology
  • S12: Reading the aquatic landscape and connecting restoration design
  • S13: Sea Grant role in communicating needs to inform research and conservation
  • S14: Bridging the Gap between Fish and Wildlife: Discussions on Multi-Species Interactions and Ecosystem Stability
  • S15: Collaborating with community members: the human side of fish and wildlife management and research
  • S16: Agriculture and Wildlife Coexistence in the Midwest United States
  • Student Event
  • T01: Fisheries: Great Lakes I
  • T02: Wildlife: Urban-Wildlife Conflict
  • T03: Fisheries: Behavior & Physiology
  • T04: Wildlife: Wetland Conservation
  • T05: Lightning Talk Session: Fisheries
  • T06: Human Dimensions: Fisheries I
  • T07: Fisheries: Rivers & Streams
  • T08: Wildlife: Waterfowl
  • T09: Human Dimensions: Wildlife
  • T10: Fisheries: Invasive Species I
  • T11: Fisheries: Fish Conservation
  • T12: Wildlife: Cervids
  • T13: Fisheries: Habitat
  • T14: Fisheries: Great Lakes II
  • T15: Fisheries: Lakes & Reservoirs
  • T16: Fisheries: Invertebrates
  • T17: Wildlife: Mammals
  • T18: Human Dimensions: Policy & Engagement
  • T19: Fisheries: Early Life History
  • T20: Wildlife: Upland I
  • T21: Fisheries: Invasive Species II
  • T22: Wildlife: Turtles
  • T23: Fisheries: Big Rivers
  • T24: Wildlife: Upland II
  • T25: Fisheries: Techniques
  • T26: Fisheries: Invasive Species III
  • T27: Wildlife: Avian
  • T28: Lightning Talk Session: Wildlife
  • T29: Human Dimensions: Fisheries II
  • Workshop