• 수산해양교육연구
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• 제24권1호
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• pp.9-17
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• 2012

The relationship between adult abundance and zoea I (ZI) density of Dungeness crabs was investigated in southeastern Alaska. Commercial harvest data (catch per pot) for male crabs larger than 165 mm in carapace width were collected from the Alaska Department of Fish and Game (ADF&G) management area, district 114 and a subdivision of district 114, 114C from 1996 to 2003. Commercial harvests of Dungeness crabs in the management area varied interannually. Commercial harvests decreased until 2000 but increased beginning in 2001. ZI density was obtained from zooplankton samples collected monthly from sampling stations within the same management district from 1997 to 2004. ZI occurred mostly in May and June, but as late as July in 1997 and 2002. ZI densities increased beginning in 1999. Total densities of ZI were significantly correlated with the commercial harvest data of adult male crabs within the management area, 114C (tens of square kilometers), containing the plankton sampling stations, but were not related to total commercial harvests within the larger geographic management area 114 (hundreds of square kilometers). We suggest that larval density may be an indicator of abundance of adult populations of Dungeness crabs.

• Fisheries and Aquatic Sciences
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• 제10권2호
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• pp.86-92
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• 2007

Adult Dungeness crabs are restricted primarily in the lower part of Glacier Bay, Alaska, but the interaction of larval dispersion and adult distribution is unknown. To understand the larval occurrence in the upper part of Glacier Bay, Dungeness crab larvae, sea surface temperature (SST), and sea surface salinity (SSS) were collected at 16 near-shore and 12 mid-channel stations in Glacier Bay, southeastern Alaska during six sampling periods from March through August 2000. Each station was visited from one to five times during the entire sampling period. Geographic Information System (GIS) was used to contour SST and SSS distribution in Glacier Bay. Seven to 27 stations were visited during each sampling period. Most larvae (85% were zoeae I) occurred during May 31 to June 14, 2000. Larval density varied from none to $51.4\;100\;m^{-3}$ between stations. A few later stage larvae occurred during later sampling periods. Overall, no relationship between larval densities, and SSS, and SST existed. Larvae occurring in the upper bay were probably transported by tidal currents from the lower bay; adult Dungeness crabs in Glacier Bay have a relatively high density near the mouth of the bay but decrease sharply around 40km north of the mouth. The lack of adult crabs in the upper 60km of the bay may be related to lower salinity, resulting in sharp haloclines, or colder temperatures which are not conducive to survival or growth of either larvae or adults.

• Animal cells and systems
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• 제12권4호
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• pp.287-295
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• 2008

Variations of larval abundance and hatch timing of Dungeness crabs, Cancer magister Dana 1852, were investigated. Dungeness crab larvae were monthly collected at 16 stations arrayed in four transects, Upper Chatham, Icy Strait, Cross Sound, and Icy Point, in southeastern Alaska from May to September 1997-2004. Larval abundance at all transects was the highest in June except in the Icy Point transect. Larval abundance was the highest in the Icy Strait transect, moderate in the Upper Chatham and Cross Sound transects, and the lowest in the Icy Point transect. Zoeae I(ZI) was predominated in May; thereafter ZI decreased and late zoeal stages occurred. In May and June, small numbers of late stage larvae unusually co-occurred with ZI in three transects. These late stage larvae may have been transported from where hatching occurs earlier. The timing of ZI occurrence varied interannually and was related to degreedays during the egg incubation period of Dungeness crabs: later larval hatching in 1997 and 2002 when temperatures were colder, while earlier larval hatching in 1998 when temperatures were warmer. The distribution patterns of Dungeness crab larvae in southeastern Alaska were markedly different from those reported from other areas of the species distribution ranges: larvae occurring much later in the year, and late stage larvae occurring in inland waters.