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Ongoing project: Cisco restoration in Lake Ontario

Ellen George and Lars Rudstam (Cornell), Mathew Levine and Darran Crabtree (TNC), Mike Connerton (NYDEC), Jim Johnson (USGS-Tunison), Zy Beisinger (USFWS). Funded by The Nature Conservancy 

Ciscoes are an important prey fish for many Great Lakes predators, including lake trout. Their numbers have declined drastically in the last century due to the impacts of invasive species such as sea lamprey and alewife, overfishing, and habitat degradation. Chaumont Bay, New York contains one of the last remaining spawning populations of cisco in Lake Ontario. This project is a collaboration between Cornell University, The Nature Conservancy of New York, the NYSDEC, and the USGS, and is funded by a grant from The Nature Conservancy. The goals of the project are 1) to assess the status of the existing spawning population, 2) to locate the spawning location within Chaumont Bay, and 3) to identify any limitations to recruitment that may be affecting the population. In November and December of 2013 we attempted to identify the spawning site using radio telemetry. Further investigation into the spawning site using an egg pumping device was completed in February and March of 2014. Eggs were found on Johnson, Middle and Herrick Shoals using the pumping method, and genetic analysis confirmed all eggs as cisco. Eggs were also collected during November and December of 2014 using egg mats, which will allow us to give a density estimate of cisco egg deposition at various sites in Chaumont Bay. The USFWS Lower Great Lakes office used side scan sonar to map spawning habitat in Chaumont Bay, which will be matched with egg mat data to estimate potential production. Larval and zooplankton collections were made in the spring of 2014 and 2015; diet analysis will be completed in 2016. Larvae from 2014 were identified to species using genetic barcoding in order to investigate distribution patterns and morphometry. Cisco larvae were found in high densities (max >800 larvae/m3), whereas very few lake whitefish were found. Larvae are widely distributed throughout Chaumont Bay, and appear to move away from spawning shoals after hatching and into nearshore areas. Comparison of morphometric characteristics between cisco and lake whitefish larvae show that there is a large amount of overlap between the two species. Greater than 80% of Chaumont Bay cisco larvae had the potential to be misidentified as lake whitefish when using visual methods and standard keys.