Grass Carp Spawning in Lake Erie Tributaries: When and Where?

Session: 02b. - Status and Management of Invasive Carps in the Great Lakes

Christine Mayer, University of Toledo, Lake Erie Center, [email protected]
Nicole King, University of Toledo, Lake Erie Center, [email protected]
Patrick Kocovsky, U.S. Geological Survey, [email protected]
Song Qian, University of Toledo, [email protected]

Abstract

Grass carp spawning was confirmed in the Great Lakes in 2015 when eight fertilized eggs were collected from the Sandusky River, Ohio, a Lake Erie tributary. In 2016 no eggs were found despite extensive effort, likely because high flow events necessary for grass carp spawning did not occur. In 2017, with increased sampling effort, 7,000+ eggs were collected during two high flow events. CPUE was substantially higher in 2017 than in 2015. The pattern of egg developmental stage and location indicated protracted spawning. We observed substantial variation in egg developmental stage at the river mouth.  Eggs that do not hatch in the river are more likely to sink and die. Therefore, developmental stage at export is an important factor in potential recruitment.  Additionally, five eggs were collected during high flow, 17 km upstream of the mouth of the Maumee River, Ohio.  Two of the Maumee River eggs were late developmental stage (23 of 31) and likely to hatch within the river.  It is now crucial to determine if, where, and when recruitment is occurring to prioritize management actions. Knowledge gained from grass carp will help speed future responses if other invasive carp species are detected in the Great Lakes.  

1. Keyword
carp

2. Keyword
exotic species

3. Keyword
tributaries