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Histological analysis of deepwater sculpin ovaries supports single spawning reproductive strategy

July 5, 2024

Deepwater sculpin (Myoxocephalus thompsonii) were considered extirpated from Lake Ontario prior to the 1990s but have since resurged and are now an abundant offshore demersal species. As deepwater sculpin reproduction is poorly described, an investigation of their gonadal development and fecundity was conducted to better understand their reproductive biology. To evaluate spawning period duration and if females spawn multiple times during their spawning period, we compared deepwater sculpin gonadosomatic index (GSI), gonadal development, and fecundity using individuals collected in fall and spring from 2018 to 2021. Our analysis revealed female GSI was greater in fall (8.1 ± 6.2 %) than spring (4.4 ± 4.3 %). Absolute fecundity averaged 763 ± 246 oocytes and relative fecundity averaged 19 ± 6 oocytes per gram of fish. Histological analysis revealed the presence of only one batch of developing oocytes in the ovary (n = 60), indicating group-synchronous ovarian organization. Our findings suggest deepwater sculpin spawn once annually but have a protracted spawning season indicated by prolonged elevated GSI values. Therefore, protracted spawning in deepwater sculpin likely results in an extended period of larval emergence rather than the majority occurring in late spring as previously suggested. A longer timeframe for deepwater sculpin larval emergence may increase reproductive success and contribute to their population’s recovery.

Publication Year 2024
Title Histological analysis of deepwater sculpin ovaries supports single spawning reproductive strategy
DOI 10.1016/j.jglr.2024.102375
Authors Jarrod R. Ludwig, Brian C. Weidel, Brian O'Malley, Michael Connerton, Jacques Rinchard
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Great Lakes Research
Index ID 70255858
Record Source USGS Publications Warehouse
USGS Organization Great Lakes Science Center