Using a multi-parameter approach to reassess maturity of spiny dogfish, Squalus acanthias, following increased fishing pressure in the Western North Atlantic

• We examined maturity for Squalus acanthias, following increased fishing pressure.
• A multiparameter approach and updated age estimates were used to improve results.
• Female age and size at maturity decreased following increased fishing pressure.
• Male age and size at maturity increased following increased fishing pressure.
• Significant change in maturity occurred in the western Atlantic from prior studies.

Age at size was linked to sexual maturity in 147 male and 249 female spiny dogfish, Squalus acanthias, from the Gulf of Maine using three criteria: (1) gross reproductive morphology, (2) histology and (3) steroid hormone concentrations. Collected specimens ranged from 25 cm to 102 cm stretch total length, and 0 to 24 years old. Maturity ogives for males, based on data gathered for clasper length, circulating testosterone concentrations and proportion of tissue with mature spermatocysts within the testes, predicted that 50% maturity occurred at a total length of 63.1 mm and 7.5 years of age. For females, maturity ogives, based on data gathered for embryo presence, ovary mass, shell gland mass, follicle size and circulating estradiol concentrations, predicted that 50% maturity occurred at a total length of 76.9 cm and 9.1 years of age. These maturity parameters for females decreased by over 7 cm and 3 years from those previously reported two decades ago for S. acanthias in the Western North Atlantic. While the causes for the decrease in maturity parameters could not be determined, as this was beyond the scope of the current study, these changes occurred over a period of increased fishing pressure.