Abstract
Pelagic shrimp, Sergia lucens, is an important commercial species of which fisheries are endemic to Suruga Bay. Although the wild shrimp are known to live for about 15 months, adults survived at most one month in previous culture studies. Therefore we challenged to keep the adult shrimp longer in the laboratory by using clean and cold deep-sea water (DSW) pipelined from a depth of 687 m in Suruga Bay in 2004. In the present paper, growth and survival of wild shrimps (nine or ten individuals of 10.15-11.69 mm in carapace length (CL)) were compared between two culture media, DSW and surface seawater (SSW, pipelined from a depth of 24 m). The shrimps were fed Artemia nauplii and kept individually in 1 liter beakers controlled at about 15°C. As the result, the average periods of survival were 58.8 days in DSW and 13.0 days in SSW. At the longest case, an adult could survive for 185 days in DSW. Even after 17 days, when no shrimps survived in SSW, 44.4 % of shrimps survived in DSW. The average (maximum) frequencies of molts per individual were 3.4 (15) times in DSW and 0.2 (1) times in SSW, respectively. The average period from start of rearing to the first molt was 15.8 days, and the average intermolt period was 12.0 days in DSW. The relationship between premolt and postmolt CLs could be described by the equation, y = 0.7156x + 2.71 (r = 0.80, n = 31, p< 0.001). The growth rate obtained in the laboratory was similar to that estimated from wild stock in the previous study. As shown in the present paper, DSW is a good tool for the long-term culture of adult shrimp, which may ensure the increase in ecological information of this shrimp.
