Reproductive ecology of the Argus brief squid Lolliguncula argus in the coast off Oaxaca, southern Mexican Pacific

Abstract

Abstract Lolliguncula argus is a squid species endemic to the Tropical Eastern Pacific and caught incidentally by the artisanal fishery around Puerto Angel, Oaxaca (Mexico). Due to the low abundance of Argus brief squid, basic aspects of the species’ reproductive biology have not been adequately studied. Therefore, in this study, we assess size at maturity (L50), gonad maturation, ovarian development and spawning pattern by means of both histological and oocyte size–frequency analyses. Our results are based on 581 squid specimens: 534 females (11.9–82.4 mm dorsal mantle length, DML) and 47 males (16.0–68.2 mm DML) caught by artisanal fishery from May 2017 to April 2018. The L50 was 58.0 mm DML for females and 55.4 mm DML for males. The ovulation pattern in L. argus is asynchronous, with multiple-batch spawning in a relatively short period of time (intermittent spawning). Lolliguncula argus breed in the coastal waters off Puerto Angel, in the western margin of the Gulf of Tehuantepec, and exhibit gregarious behaviour during spawning events, which is associated with the regional oceanographic conditions. Based on these results, we determine that the opportunistic reproductive strategy of L. argus occurs in response to suitable regional environmental conditions.