Date of Award

Fall 8-31-2024

Document Type

Thesis: Open Access

Degree Name

MS Marine Science

Department

Environmental and Ocean Sciences

Committee Chair

Andrew Nosal

Abstract

Multiple paternity has been widely documented in elasmobranch fishes (sharks, rays, and skates); however, the frequency of multiple paternity (FMP; the percentage of sampled litters having multiple sires) varies greatly both among and within species. Understanding the reasons for this inter- and intraspecific variation in FMP may be key to understanding why females mate with multiple males. The soupfin shark (Galeorhinus galeus) is an understudied species in this regard with only one study previously investigating multiple paternity, in which two out of five litters sampled from New Zealand were found to have multiple sires (FMP = 40.0%). We augmented this small sample size by genotyping an additional ten litters sampled from central South Australia, Australia (mean litter size = 32.6 ± 7.8 pups) as well as ten litters sampled from southern California, USA (mean litter size = 30.9 ± 8.5 pups). Multiple paternity was detected in four of the ten litters sampled from Australia (FMP = 40.0%) and two of the ten litters sampled from California (FMP = 20.0%). Our findings were generally consistent with the previous study of this species and we conclude that G. galeus exhibits a relatively low FMP when compared to other elasmobranch species.

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