Presence of juveniles and adults of the “glass” squid Leachia dislocata (Cephalopoda: Cranchiidae) in the Gulf of Tehuantepec, northeastern tropical Pacific

Background: Within the Cranchiidae family, species of the genus Leachia known as "glass" squid, have a cosmopolitan distribution. There are three species that inhabit the tropical Pacific: L. pacifica, L. danae and L. dislocata. However, due to few records, very little is known about basic biological aspects of this group. Objective: In this work, the presence of juveniles and adults of L. dislocata is reported for the first time, and data on its size structure, sex ratio and weight-length relationship are also provided. Methods: L. dislocata specimens were collected during April 2022, in a fishing and oceanographic cruise aboard the research vessel Dr. Jorge Carranza Fraser of the Mexican Institute for Research in Sustainable Fisheries and Aquaculture of the National Institute of Fisheries and Aquaculture of the Government of Mexico. 50 distributed fishing hauls were made, after visualization with a scientific echo sounder. Results: 128 organisms of L. dislocata were presented, with a total of 82 females, 34 males, and 12 juveniles. The sex ratio had a clear predominance of females (3H:1M, p < 0.05). The relationship between mantle length and weight for females and males presented a negative allometric growth (p < 0.05). Conclusions: These new records represent the southernmost limit of the geographic distribution of this species. On the other hand, the presence of juveniles and adults reported here, along with previous records of paralarvae, provide evidence that the Gulf of Tehuantepec is a breeding area for this species.