Holding wild caught red king crab, Paralithodes camtschaticus: effects of stocking density and feeding on survival and meat content

Abstract

In this study, the effects of different stocking densities on survival, injury and meat content of captive male red king crab (mean weight = 2.6 kg) were examined. The first experiment was carried out in square plastic tanks with stocking densities of 100, 150 and 200 kg m−3 for 56 days. In a second experiment, king crabs were kept at a stocking density of 60 kg m−3 and were either fed or not fed. Both mortality and occurrence of injuries increased significantly with increasing stocking density. In the highest density groups, mortality and frequency of injury was 17% and 14% respectively, compared with 5% and 4% in the 150 kg m−3 group. The percentage meat content was significantly lower at the final census compared with the initial census in all stocking density groups. In Experiment 2, there were no mortalities or injuries in either the fed or unfed treatments. The average percentage meat content increased in the fed treatment and decreased in the starved treatments. The results show that adult male king crab can maintain high survival rates at stocking densities up to 150 kg m−3 in holding facilities of the design used in the present study for periods up to 2 months. However, to reduce mortality and frequency of injury over this period densities as low as 60 kg m−3 and a holding system with a large bottom surface area are recommended.

Holding wild Snow crab, Chionoecetes opilio : effects of stocking density and feeding on survival and injury

“…The snow crabs in this experiment were probably not held under optimal conditions, so further examination of how the snow crab rear-ing conditions can be optimized is necessary. These results are not similar to the results for stocking density studies with red king crab under equal conditions (Siikavuopio et al 2016), were it was possible to hold king crabs up to 150 kg m À3 . Although there is an abundance of literature covering stocking density effects in other crab species culture.…”

“…The relatively new industry in Norway based on the live export of king-and snow crab will rely on a consistent supply of wild-caught crabs, held in land-based facilities for periods varying from a few days to a few months (James, Vasilyev, Siikavuopio, Kovatcheva & Samuelsen 2013;Lorentzen et al 2015;Siikavuopio & James 2015;Siikavuopio et al 2016). During this 'transit' period when they are held in land-based facilities they will need to survive and maintain their quality at an acceptable level for both animal welfare standards and for discerning export markets.…”

“…The development of live holding and export of snow crab from Norway depends on both a reliable and consistent supply of crabs and the ability to hold and transport these, in good condition, to overseas markets. Since it has been shown for red king crab (Paralithodes camtschatica) that increasing stocking densities increases the risk of cannibalism and injuries (Stoner 2012;Siikavuopio & James 2015;Siikavuopio, James, Evensen & Mortensen 2016), it is important to determine the maximum stocking density for live holding snow crabs both for economic and animal welfare reasons. Capture-based aquaculture of snow crab is developing in Norway and several other countries, and effort has been put into establishing smalland medium-sized enterprises using intensive culture systems for live holding snow crab (Lorentzen et al 2016).…”

Current Status of the Red King Crab (Paralithodes camtchaticus) and Snow Crab (Chionoecetes opilio) Industries in Norway

“…Mortality rates during live storage of both RKC and SC depend on several biotic and abiotic variables. The SC is more sensitive to high temperature and high stocking density during live storage than RKC (James et al, 2013;Siikavuopio and James 2015;Siikavuopio et al, 2016). Generally speaking, RKC is more robust and exhibits a lower mortality rate than SC during live storage and live export.…”

“…Thus, new techniques for both short-term (vessel) and long-term (land) live SC storage need to be developed. In RKC, increasing temperature and stocking density increase the risk of cannibalism, mortality, and injuries (Siikavuopio and James, 2015;Siikavuopio et al, 2016). Thus, it is important to determine the optimum environmental conditions for SC, such as temperature, water requirement, and stocking density.…”