Distribution and Size of the Pacific Deep Water Lobsterette, Nephropsis Occidentalis Faxon, 1893 (Decapoda, Astacidea, Nephropidae) In The S.E. Gulf of California, Mexico.

The medium size Pacific lobsterette, Nephropsis occidentalis Faxon, 1893, is known from only a few records in the east Pacific (Gulf of California to Chile). A recent survey of deep-water benthic communities in the S.E. Gulf of California, Mexico, indicates that it is abundant at depths between 1050 and 1310 m and is tolerant to severe hypoxic conditions (0.38 to 1.4 ml O2/l, with six catches in less than 1 ml/l). Maximum individual size (135 mm, total length) and body weight (31.2 g) are relatively low compared to shallow water commercial shrimps fished in the region, but the species represents a potential by-catch fishery of the pandalid shrimps Heterocarpus affinis Faxon, 1893 and Pandalus amplus Bate, 1886. Sex ratio (n = 46) F : M was 0.6 : 1. The carapace/total length relationship was significantly different between sexes, while fresh weight/total length relationship was not (t-test on slope and Y intercepts; 0.95). The largest specimens (135 mm TL) barely reach 30 g (29.9 g for the largest male; 31.6 g for the largest female) of fresh weight (30-35 large size specimens per kg of fresh product). Tail weight with carapace is slightly lower than 9 g of fresh weight for the largest specimens (average of 36.5% of total fresh weight). Tail weight without carapace is in the range of 4.5 to 5.6 g for larger specimens. [ABSTRACT FROM AUTHOR]