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| Gulf of Alaska |
| Bering Sea/Aleutian Islands |
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| Fish Habitat |
| Fish and Invertebrates |
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| Bering Sea |
| Gulf of Alaska |
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| blue king crab |
| larvae |
| cultivation |
| red king crab |
| habitat |
| settlement |
| behavior |
| growth |
| competition |
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| Fish Habitat |
| Endangered and stressed species |
| Marine Ecosystem structure and processes |
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316 Essential fish habitat for blue king crab, Phase 1: Development of cultivation techniques for blue king crab larvae
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| Year funded: |
2003 |
| Start date: |
Jul 01, 2003 |
| End date: |
Mar 01, 2005 |
| Budget: |
$85,561.00 |
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Websites:
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Followed by:
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The goal of this project was to understand the relationship between Essential Fish Habitat (EFH) for “overfished” Pribilof Islands blue king crab (BKC) and survival in the first year of life. The first year’s goals were to develop techniques for cultivation of BKC larvae, verify our ability to raise them in the laboratory, and determine the optimum conditions for cultivation.Larvae of the blue king crab (Paralithodes platypus) were cultivated in a non-factorial experiment to test the effects of diet, temperature, and rearing density. Diets tested included no feeding (UNFED), Artemia nauplii enriched by feeding with diatoms Thalassiosira nordenskioeldii (THAL), unenriched Artemia fed in addition to Thalassiosira (A+THAL), and a
control diet of Artemia enriched by feeding with frozen Isochrysis paste (ISO).All diets were tested at 6 C, and a density of 10 zoea·l-1, with 6 replicates per treatment. The ISO diet was also tested at 3 C (ISO 3) and 9 C (ISO 9), and at densities of 20 (ISO 20) and 40 (ISO 40) zoea·l-1. Survival on the A+THAL diet (91.7%) was significantly higher than all others, whereas UNFED larvae died within two weeks. Survival decreased slightly with increasing temperature, but not significantly. Density had no significant effect on survival, but final mean density (16 zoea·l-1) was similar in the ISO 20 and ISO 40 treatments suggesting that a maximum carrying capacity for these conditions had been reached. | | Glaucothoe after molting to the first crab (C-1) stage. Its coloration closely matches the broken cockle shells among which it prefers to hide. |
Length of development to the first juvenile crab stage (C1) was significantly longer (109 d) at 3 C than at 6 C (70 d), but did not decrease further at 9 C. Half of the replicates in the ISO 20 and ISO 40 treatments were fed continuously during the postlarval (glaucothoe) stage (all other treatments were not); survival of continuously fed larvae was higher in the latter treatment but not the former.We concluded from this research that blue king crab larvae can be cultivated with high survival using the proper diet, that larvae are not lecithotrophic (i.e., they need to feed), and that glaucothoe do not feed. These results can be used to produce larger numbers of juvenile crab for laboratory research, and could be modified for use in stock enhancement.
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| Bradley Stevens |
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| NOAA National Marine Fisheries Service |
Kodiak Fisheries Research Center; 301 Reasearch Ct.
Kodiak AK 99615 USA |
Phone: (907) 481-1726
Fax: (907)481-1701
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