Distribution and reproductive biology of a subantarctic deep-sea lobster, the Patagonian lobsterette Thymops birsteini (Zarenkov and Semenov, 1972) (Decapoda, Astacidea, Nephropidae)

Abstract

The Patagonian lobsterette Thymops birsteini was found in the southwest Atlantic between 175 and 1663m. Predominating size of lobsterettes increased with depth from the upper slope (200-400m) to a maximum size at a depth of 1000-1400m and then decreased with increasing depth (1400-1600m). Ovigerous females were found between 584 and 1480m. Fecundity (eggs on pleopods) varied from 25 to 378 and egg size was 1.5-1.9mm, increasing during embryonic development to 2.9-3.3mm. Hatched larvae were found attached to pleopods; their carapace length was 1.7-2.2mm. Number of larvae on pleopods (from nine to 43) was much lower than the actual fecundity, indicating that hatching is probably extended. Such an extended larval release was found in other subantarctic decapods and it is an adaptation to low fecundity, long brooding period and low temperatures.