Abstract

The diamond squid, Tysanoteuthis rhombus, is a large species of squid, widely distributed in tropical and subtropical waters worldwide. The life span of the species is one year and they reach maturity at 6-8 months of life (Nigmatullin et al., 1995). They are normally found swimming in pairs and are believed to be monogamous, pairing for life (Nigmatullin et al., 1995; Nigmatullin & Arkhipkin, 1998). In their adult and mature stage, males can be differentiated externally from females by the modification of the fourth left arm (ventral) into a copulatory organ or hectocotylean arm (Nigmatullin et al., 1995). In tropical waters this species spawns throughout the year, and the presence of masses of fully mature eggs, larvae, and adults indicates spawning grounds (Nigmatullin et al., 1995). The only country with a developed diamond squid fishery (beginning in the 1960s) is Japan, where the “taru-nagashi” fishing gear was invented, a type of light line fishing designed exclusively for squid (Arkhipkin et al. al., 2015). In Okinawa alone, the estimated annual production from 2001-2010 was US$9-19 million, with the catches second only to tuna (Arkhipkin et al., 2015). Being an important economic resource for Japan, studies have also been conducted on the vertical migrations and horizontal distribution of the species. The latter depends on the currents and the temperature of the water column (Miyahara et al., 2007, 2008). In the Dominican Republic there is a small-scale artisanal fishery, started with the support of the Japanese government in 2001, in the extreme east of the Samaná Peninsula. Based on a survey of biological fishing information in the Bay of Samaná, Betancourt (2010) and Herrera et al., (2011), described a diurnal and seasonal fishery for diamond squid (mainly from October to February), composed of only 6