Reproduction in Parachaenichthys charcoti (Bathydraconidae) in West Antarctica.

MOREIRA, EUGENIA; NOVILLO, MANUEL; BARRERA-ORO, ESTEBAN; MACCHI, GUSTAVO

Davos

Congreso; POLAR2018 Open Science Conference; 2018

Scientific Comitte of Antarctic Science

The reproductive biology of dragon fishes is poorly understood and particularly in P. charcoti (PCH). A histological analysis of PCH ovaries together with reproductive effort data using fish caught at Potter Cove, South Shetland Islands (SSI), are compared with data reported for the South Georgia´s congener P. georgianus (PGE). In gravid females of PCH, GSI of 16-31%, mature oocytes of 1.8-3.9 mm and total fecundity (TF) of 9790-18937 oocytes/individual (mean 13216) were recorded. The histology of the ovaries confirmed the common characteristics of the suborder Notothenioidei observed macroscopically, i.e., two distinct batches of oocytes, one in previtellogenic stage, and the other in vitellogenesis and likely to be released in the current season. A longer incubation period of PCH compared to PGE is associated to colder waters at the SSI. Our sampling and reproductive effort data and the known nesting behavior of PCH, everything recorded at Potter Cove, suggest that this species spawns nearshore in summer, from late Dec to Feb. Spawning periods of both congeners differ from those reported for other notothenioids in the Seasonal Pack-ice Zone, suggesting divergence in some aspects of the life strategies in the genus Parachaenichthys. Likewise, although there are no substantial differences between PCH and other notothenioids regarding gonadal development, this genus shows distinct features in its reproductive strategies (e.g. higher TF) in comparison with other bathydraconids.