Increased Walleye Egg-to-Larvae Survival following Spawning Habitat Enhancement in a Tributary of Eastern Lake Ontario

Abstract

To mitigate the effects of sedimentation from surrounding land use, a Newbury weir was installed in Kent’s Creek (a tributary of eastern Lake Ontario) by the U.S. Fish and Wildlife Service Partners for Fish and Wildlife Program to enhance spawning habitat for Walleye Sander vitreus. By adding angular crushed limestone, the Newbury weir was designed as an engineered spawning riffle that creates a scouring effect to maintain clean spawning substrate for Walleyes. To evaluate the success of the Newbury weir, we compared rates of egg deposition, egg viability, and larval out-migration between the created spawning riffle and a natural spawning bed for two seasons subsequent to its construction. Spawning Walleyes were found to immediately spawn on the created riffle following construction and demonstrated similar patterns of egg deposition and larval out-migration at both sites each year. When data were pooled between years, significantly higher densities of out-migrating larvae were observed at the Newbury weir despite the finding that significantly more eggs were spawned at the natural site. Considering that egg viability was similar between sites, we deduce that the created riffle had a higher egg-to-larvae survival rate. Our results suggest that the Newbury weir successfully created functional spawning habitat promoting out-migrating larval Walleyes. We anticipate that the created riffle will maintain valuable spawning substrate for Walleyes, but sediments deposited from upstream eroding banks and agricultural land use practices could affect its long-term viability. We recommend that future spawning habitat enhancement projects adopt similar approaches within appropriate fluvial geomorphic settings and additionally consider watershed-scale improvements to enhance Walleye spawning tributaries.

Received March 17, 2017; accepted May 26, 2017 Published online August 9, 2017

Acknowledgments

Many organizations and individuals assisted with project implementation and data collection. Specifically, we thank the U.S. Fish and Wildlife Service Partners for Fish and Wildlife Program, the Fish Enhancement, Mitigation, and Research Fund and its Fisheries Advisory Committee, and the New York Department of Environmental Conservation for funding and assisting with the design and implementation of the Newbury weir. A special thanks to Carl Schwartz and Scott Schlueter of the U.S. Fish and Wildlife Service and Steven LaPan and Frank Flack of the New York State Department of Environmental Conservation for logistical and planning support. We also are indebted to the staff, students, and technicians of the Thousand Islands Biological Station for assistance in data collection. We also appreciate the efforts of three anonymous reviewers whose comments and suggestions greatly improved the quality of this manuscript. We also would like to thank the private landowners, the Thousand Islands Land Trust, and the New York SeaGrant for additional assistance. This research is a contribution of the Thousand Islands Biological Station.