Where's Walleye, The search for a modern fish survey technique to study ghost forests in coastal wetlands

Nets have been used to capture fish since the Stone Ages, however, due to climate change altering the hydrological regimes of the Laurentian Great Lakes, researchers may need a more modern solution to survey fish communities. Once rare, patches of ghost forests have increased on the nearshores of Georgian Bay coastal wetlands, created by a sustained low-water period. Once water-levels rose, these inundated meadow species (IMS) made past net survey techniques ineffective. As such, our lab has developed an underwater camera array which is no longer depthdependent and is less invasive to fish communities. In 2022, 10 coastal wetlands with ghost forest patches were sampled with this array using a paired design, where a camera stand was placed in-front of the IMS and another behind. After collecting thousands of hours of videos, we partnered with Zooniverse, creating the online citizen project, “Where’s Walleye?”, to pre-process the collected footage. We hypothesize that the more rigid structure of the IMS may reduce fish access to the nearshore of coastal wetlands, where smaller and younger fish species are expected to be found in greater proportions behind the IMS than in-front. This project not only aims to address how ghost forests in freshwater coastal wetlands may impact fish communities, but can also be used as a pilot study, to address the increasing challenge of handling big datasets and how citizens can contribute to science.

Where's Walleye, The search for a modern fish survey technique to study ghost forests in coastal wetlands Presentations