Snap-a-Striper: Morphometrics, Otoliths, and Citizen Science in Stock Discrimination of Striped Bass in Maine.

Whitener, Zach¹, Lisa Kerr², Graham Sherwood¹, ¹Gulf of Maine Research Institute, Portland, ME, ²University of Maine

Striped bass (Morone saxatilis) are iconic anadromous fish that are known to exhibit large-scale seasonal migrations along the Atlantic coast of North America, with only a single known spawning population within Maine watersheds. Striped bass are an important component of the recreational fishery in coastal Maine, with the catch comprising both native and non-native fish. Understanding the relative contribution of locally spawned fish from the Kennebec River versus migratory fish from more productive southerly populations to the coastal striped bass fishery in Maine is integral to local stewardship efforts and sustainable management of a fishery that contributes significantly to recreation and tourism in the state. Snap-a-Striper is a citizen science program initiated by the Gulf of Maine Research Institute to collect scientific samples of stripers caught in the primarily catch-and-release recreational fishery, primarily through non-lethal means for morphometric analysis, as well as otolith sampling from legally harvested fish. We used otolith chemistry to groundtruth spawning areas for a subset of morphometric data, but regulatory changes made obtaining samples difficult. We analyzed 1330 photographs for striped bass caught between 2013 and 2019, using the residual morphometric data derived from 13 landmarks and 27 box-truss measurements for principal component analysis. Discriminant function analysis of those principal components correctly identify individual fish to place of capture in the Kennebec 57.23% of the time, 72.99% outside the river, and 65.78% overall. This study highlights both the advantages and challenges of utilizing citizen science for fisheries research.