Comparing the Hickory Shad (Alosa mediocris) and American Shad (Alosa sapidissima) Sport Fishery Using Age and Spawning Composition and Social Media.

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Samantha A. Dowiarz (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: The goal of this study was to compare aspects of Hickory Shad (Alosa mediocris) (Mitchell 1814) and American Shad (Alosa sapidissima) (Wilson 1811) life history while also providing supplemental information on their age and spawning composition, recreational catch and effort, and geographical distribution for future stock assessments. Hickory and American shads are anadromous fish species native to the East Coast of North America that ascend freshwater watersheds to spawn in the spring. Exactly how similar these two species are in life history is unknown, but the two species are co-managed federally by the Atlantic States Marine Fisheries Commission. Based on the 2020 stock assessment, American Shad are in a state of decline in multiple watershed along the spawning range, but it is unknown whether Hickory Shad are experiencing the same decline because the lack of scientific literature makes a benchmark coastwide stock assessment impossible to complete. The first objective of this study was to compare the age and spawning composition of Hickory Shad captured from different river systems along their range. Since aging protocols for Hickory Shad scales and sagittal otoliths were never published in the primary literature, the Massachusetts Division of Marine Fisheries American Shad Ageing Protocol was used in its place. A subsample of transversely sectioned otoliths were aged, coupled with otolith microchemistry, and compared to whole otolith ages. The results determined that Hickory Shad otoliths should be aged slightly differently than American Shad, an aspect of their life history that disagrees with their current co-management. Otoliths were the more precise aging structure, so a sex-specific age-length key for North Carolina was created from 240 Hickory Shad otoliths aged from the Rulifson Lab. The keys were then used to assign ages to length data provided by the North Carolina Wildlife Resources Commission (NCWRC) and North Carolina Division of Marine Fisheries (NCDMF) to create a length-at-age distribution. Fish used in this study were primarily grab samples from agency spring monitoring and so results may not accurately extrapolate to the entire spawning population\; however, with the exception of Georgia the results here suggest a latitudinal repeat spawning gradient of increased iteroparity from south to north, a trend also observed for the American Shad. Both species comprise important recreational fisheries throughout their ranges, so much so that a Facebook group named "NC-Shad" was created in 2013 for anglers to post about their fishing trips, successful or otherwise. From 2013-2020, a total of 1,790 posts were analyzed to determine angler demographics, lure characteristics, and catch information. From all posts, 1,398 included location information, so Geographic Information Systems (GIS) was employed to examine spatiotemporal patterns in fishing location and Hickory Shad and American Shad Catch Per Post (CPP). Catch Per Post was used in place of Catch Per Unit Effort (CPUE) because not every post indicated the number of anglers present, so effort could not be assessed based on this data collection method. Although significant spatiotemporal trends were not found based on both Hickory and American shad CPP, an overall positive trend in Hickory Shad CPP and negative trend in American Shad CPP is apparent throughout the study period. These opposing CPP trends suggests that something, whether it is anthropogenic or naturally occurring, is affecting American Shad more drastically than Hickory Shad. The "NC-Shad" CPP was also compared to the CSMA anadromous creel survey CPP obtained annually by the NCWRC, and multiple years within multiple watersheds were found to have significant differences in CPP for both Hickory and American shads. One caveat in this comparison is that creel surveys do not collect information from bank anglers, but many posts from "NC-Shad" were from bank anglers, which may explain some of the CPP differences. This study demonstrated that social media is a technological adaption with potential to form a recreational angler citizen science network based on Local Ecological Knowledge (LEK). Social media data mining could be a cost-effective alternative to obtain supplementary information on recreationally important fish species, and viable technique for the future of fisheries management.

Additional Information

Publication

Thesis

Language: English

Date: 2023

Subjects

Otolith;Spawning Marks

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