Fish in Phrag: Quantifying habitat use of freshwater fishes in native and non-native emergent stands

Session: 34. - Aquatic Habitat Evaluation and Assessment

Abby Wynia, Trent University / Fisheries and Oceans Canada, [email protected]
Jon Midwood, Department of Fisheries and Oceans, [email protected]
David Reddick, Fisheries and Oceans Canada, [email protected]
Clint Jacobs, Walpole Island Heritage Centre, [email protected]
Susan Doka, GLLFAS, Fisheries & Oceans Canada, [email protected]
Thomas Whillans, School of the Environment, Trent University, [email protected]

Abstract

Invasive Phragmites australis ssp. australis (herein “Phragmites”) has established and rapidly spread throughout many coastal areas of the Great Lakes. It has displaced native emergent species potentially changing spawning, nursery and foraging habitat for fishes. The extent to which Phragmites provides habitat for freshwater fishes is currently unquantified, although widely suspected to be unsuitable. This study assesses whether fish assemblages in stands of Phragmites differ from that in stands of two native emergent species, Typha spp. and Schoenoplectus spp. The focus is on marshes within the St. Clair River Delta, which are similar in terms of species pool, water levels and the degree of shoreline disturbance. Habitat data (e.g., water quality, water temperature, stem density, and substrate type) was collected concurrently to help identify potential drivers that may influence fish richness and production. The preliminary results of this study suggest that invasive Phragmites does provide suitable habitat for freshwater fishes, although not entirely comparable to that provided by native emergent habitats. This study will provide collaborating management agencies, Walpole Island First Nation and Fisheries and Oceans Canada, with quantitative data on potential impacts to fish and fish habitat associated with the spread of this invasive species.

1. Keyword
Phragmites australis

2. Keyword
fish

3. Keyword
species composition

4. Additional Keyword
fish habitat

5. Additional Keyword
St. Clair River