An estimate of intrinsic rate of increase is not available for king crabs. Estimates of age at maturity range from 5 to 12 years, with a mean age at maturity at 6-7 years (Kruse, G., pers. comm., 11/10/04). Red King Crab can live at least 20 years (Kruse, G., pers. comm., 11/10/04). The maximum age of the other three species was not reported in literature reviewed.

Immature Red King Crab between 2 and 4 years of age tend to form protective pods consisting of thousands of crabs. At 4 years old, members of this species generally move to deeper water and join adults in seasonal migrations to mating/molting and feeding grounds. One study revealed “mega-aggregations” of spawning crabs that covered an estimated tens of miles in diameter, with greatest abundance near the center. Blue King Crab do not form pods (NPFMC 1998a), but do aggregate to breed (Blau 1997). Breeding aggregations have not yet been reported for Golden King Crab but evidence of “loose” aggregations exists (Hoyt and Shirley 2000).

Female Red King Crabs brood eggs underneath their tail flap for about 11 months (ADF&G 1985), and Blue King Crabs brood eggs for 14 months (NPFMC 1998a). King Crabs are particularly vulnerable to predation or handling when molting, and females must molt in order to mate (Blau 1997).

Red King Crab have the widest distribution of the four species. In Asian waters, this species occurs from the Sea of Japan northward into the Sea of Okhotsk and along the shores of the Kamchatka Peninsula. In the northeast Pacific, distribution extends northward from Vancouver Island, British Columbia, to Norton Sound in the Bering Sea (ADF&G 1985). Members of the Sea of Okhotsk population were intentionally introduced to the Barents Sea from 1961-69 and have successfully formed a resident self-reproducing population that is currently widely distributed in coastal waters off Russia and Norway. The life history traits of this population are similar to those of the Pacific population (Savinov 2000).

Blue King Crab has a discontinuous distribution from Hokkaido, Japan to Southeast Alaska. Golden King Crab range from Japan to British Columbia (Blau 1997). Scarlet King Crab can be found from southern California to the Bering Sea (McCrae 1994). No points were subtracted or added here; we consider this to be an average size range.

Unlike fish, for which scientists can identify ages precisely and then compare abundance in particular years to environmental conditions in the same period, crabs are impossible to age. Consequently, it is more challenging to determine how changing environmental conditions affect crabs. Some crab populations, however, do appear to exhibit variability in response to environmental conditions (Zheng and Kruse 2000). NMFS’ trawl surveys and fishery data show that abundance of King and Tanner Crabs changes significantly over time, which is mainly the result of ecosystem processes controlling early life history stages.

For relatively long-lived species like King, Snow, and Tanner Crabs, good larval survival is not critical every year, and populations can sustain several years of low larval survival. (In contrast, populations of short-lived species like some species of tropical shrimp, which mature at age 1 and die by age 2, depend on each year’s production of larvae.) However, if physical processes are either favorable or adverse to good larval survival for longer periods of several years, overall abundance and spatial distribution of crab populations can change significantly. When environmental regimes (which involve water temperature, wind direction, and extent of annual ice coverage) shift, crab populations may be affected. For example Tanner crab larvae cannot tolerate very cold water and may not survive in areas where temperatures are unfavorable. Consequently, if a cold regime persists for several years there will no repopulation in areas where the crabs are found during warmer regimes (NMFS 2003).

In U.S. King Crab fisheries, the minimum stock size threshold (MSST) is defined as 50% of the mean total spawning biomass (SB = total biomass of mature males and females) for the period 1983-1997, upon which the maximum sustainable yield (MSY) is based. A stock is considered to be overfished (regardless of cause) if the SB falls below the MSST (NPFMC 2002a). Four Bering Sea King Crab populations are surveyed annually: Bristol Bay Red King Crab, Bering Sea Pribilof Islands Red and Blue King Crab, and St. Matthew’s Island Blue King Crab. The SB of the former two populations is currently above MSST. However, fishery managers have low confidence in the abundance indices for Pribilof Islands Red King Crab and are concerned about incidental catch of this species. The latter two populations are below MSST and are designated as overfished. Fisheries for all of these populations except for Red King Crab in Bristol Bay, Norton Sound, and southeast Alaska are closed in U.S. waters (Kruse, G., pers. comm., 11/10/04).

The status of all remaining King Crab populations is unknown (NMFS 2002). Reliable abundance data for King Crab populations in Russian waters are not readily available. A medium score was awarded here to account for the range of abundances in U.S. waters and the lack of information on Golden and Blue King Crabs in many regions in U.S. and in Russian waters.

In 2002, survey data indicated that the Pribilof Islands Red King Crab population experienced a 99% decrease in the number of pre-recruits and an 89% decrease in the number of females since 2001. In 2002, Pribilof Islands Blue King Crabs were designated as overfished. The St. Matthews Blue King Crab population also declined, and the 2002 survey data revealed no signs of increased recruitment in the near future (NMFS 2002; AFSC 2002). Russian King Crabs are reportedly in decline (Bean 2000; Wilhelm 2001).

On the other hand, in 2002 Bristol Bay Red King Crab population experienced an 85% increase in the number of legal-sized males and an 138% increase in the number of pre-recruits since 2001. The number of mature males doubled from 2001 levels, but the number of females in the population decreased 11% (NMFS 2002; AFSC 2002).

Seafood Business (2001) reports that the average size of King Crabs taken from Russian waters is decreasing. However, no points were added or subtracted here, as this information was not taken from an authoritative source such as a stock assessment.

In U.S. waters, the status of 11 King Crab populations is published by NOAA. Of these 11 populations, 7 populations are classified as "unknown status", one is overfished, and 3 are classified as "not overfished". In Russian waters the status of King Crab in the northwest Pacific has not been formally classified. The FAO reported in 1996 that there were indications that most King Crab grounds were fully exploited (FAO 1997). No points were subtracted here to account for the fact that only one population, Pribilof Islands Blue King Crabs, is overfished.

King Crab are captured in large wire pots baited with chopped herring, cod, and/or other fish (Ocean Bounty 2001). The U.S. fishery most commonly uses large 600- to 700-pound steel pots covered with nylon webbing. Baited pots are left to soak on the ocean floor (usually one or two days when targeting Red or Blue King Crab; longer when targeting Golden King Crab), then retrieved using hydraulic winches (Blau 1997).

King Crab is also taken as bycatch in bottom trawl fisheries. U.S. managers, however, have designated King Crab as a prohibited species in the North Pacific groundfish trawl fishery, and all trawl-captured King Crabs must be promptly returned to the sea (Kruse, G., pers. comm., 11/10/2004).

Specific threats to King Crab habitat identified by ADF&G (1985) include changes in their physical environment, habitat alteration or degradation, a reduction in food supply, the obstruction of migration routes, and human harvest (including handling of non-legal crab). However, the fact that several populations are overfished or that exploitation levels are high, indicate that fisheries are likely generating a greater impact on King Crab populations than non-fishery causes.

U.S. managers have established area closures and prohibited species caps to protect King Crabs (NPFMC 1998b).

Pots are generally set on soft bottom habitats with little biotic structure (Kruse, G., pers. comm., 11/10/2004).

King Crab fisheries are managed in both the U.S. and Russia. Management tools in U.S. fisheries include limited entry programs, catch limits, minimum size limits, prohibitions on landing female crabs, area and seasonal closures, and gear restrictions (NPFMC 2000; Reeves and Turnock 1999). However, despite this extensive management system, King Crab fisheries are overcapitalized, resulting in derby-type fishing.

Russian fisheries require permits, have catch quotas, gear requirements, size restrictions and species-specific area closures (Pautzke 1997). However, established quotas are regularly exceeded (Seafood Business 2001). Bean (2000) reports that poaching and misreporting of catch are rapidly deteriorating King Crab resources in some regions (e.g., western Kamchatka). However, enforcement has been tightened since early 2000. Medetsky (2001) writes that poaching has been widespread this year as a result of delays in distributing catch quotas under the new auction system. One vessel reportedly delivered 27.5 tons of crab before any licenses had even been distributed. A medium score was awarded here to account for overcapitalization in U.S. and Russian fisheries and problems with enforcement in Russian fisheries.

U.S. populations and landings are generally well-surveyed. U.S. King Crab fisheries are continuously monitored using in-season industry reports, fish tickets and, in some cases, state fishery observers. Observers are required on all BSAI processing vessels, and on all Golden King Crab catcher vessels operating in the Aleutian Islands area. In addition, the State of Alaska has the authority to randomly place observers onboard catcher vessels greater than 75 feet in length (NPFMC 1998a). Observers have been aboard vessels in the Bristol Bay Red King Crab fishery since the late 1980s (Kruse, G., pers. comm., 11/10/2004). Four Bering Sea King Crab populations are assessed annually (Kruse, G., pers. comm., 11/10/2004; NMFS 2001). ADF&G conducts a triennial trawl survey that provides limited information on Dutch Harbor Red King Crab, Aleutian Islands Golden King Crab and Aleutian Islands Scarlet King Crab (NPFMC 2000). The remaining Bering Sea populations are not regularly surveyed (NPFMC 1998a).

In Russian fisheries, vessel captains are required to submit biweekly catch reports to the National Administration of Fishery Enforcement (Glavrybvod). However, Russia’s monitoring and enforcement programs appear to be underfunded and understaffed (Pautzke 1997). Illegal fishing and misreporting are reportedly major problems in the King Crab fishery (Bean 2000). Scientists at the Federal Fisheries Committee’s Russian Institute of Fisheries and Oceanography (VNIRO) and at the Pacific Scientific Research Fisheries Center (TINRO-Center) conduct biological assessments of Russian Far East fishery resources. The activities of both institutions are focused on developing recommendations for exploration, conservation and optimum utilization of living marine resources (Pautzke 1997). It is not clear which, if any, of these bodies regularly assesses the status of Russia’s King Crab resources, or if fishery-independent data are routinely collected for use in stock assessments. However, it is likely that stocks are regularly assessed (based at the very least on catch report data) to provide the data needed to establish season quotas. Points were awarded here to account for the extensive monitoring of Alaskan King Crab fisheries and the efforts in place in Russia.

Measures to reduce impacts of fishing on essential fish habitat in U.S. waters were pending Council approval in 2003 (NPFMC 2002b).

In Alaska, the ADF&G developed a rebuilding plan for St. Matthew Blue King Crab that established a stock abundance threshold, a guideline harvest level, variable mature catch rates, and a cap on the legal male catch rate intended to prevent high removal rates of legal crabs when most mature males are sublegal size. The plan was adopted by the Alaska Board of Fisheries in March 2000, by the North Pacific Council in June 2000, and approved by NOAA in December 2000. (NMFS 2000). In December 2003 the North Pacific Fishery Management Council submitted a rebuilding plan for Pribilof Islands Blue King Crab, found to be overfished in 2002, to the National Marine Fisheries Service for Secretarial Review.

Despite substantial economic pressure, the Russian government has reduced the annual total allowable catch quota over the last several years. The 2001 Far East commercial catch quota was 18,606 metric tons (mt), compared to 20,249 mt in 2000 and 25,706 mt in 1999 (Pacific Rim Fisheries Program 2001). Seafood Business (2001) reports that these reductions are expected to continue. Foreign allocations have been reduced as well. For example, the 2000 Russia/Japan cooperative agreement does not grant Japanese fleets access to Russian king crab resources (Globefish 2000). Although established quotas are regularly exceeded, it is clear that Russian fishery managers are making an effort to improve the status of crab populations.

King Crab fisheries are overcapitalized in the Bering Sea and Aleutian Islands. Congress approved a fishing capacity reduction program for BSAI crabs in late 2000 (P.L. 106-554, amended by P.L. 107-20). In the intervening two years, the North Pacific Fishery Management Council has outlined a series of alternatives to amend the Fishery Management Plan for Bering Sea and Aleutian Islands King and Tanner crabs, which are presented in the Draft Environmental Impact Statement (NMFS 2003). The Council will discuss the alternatives to the crab FMP in February 2004 and take final action in June 2004 (NPFMC 2003). In January 2004 the U.S. Senate passed a bill providing funding for the new quota system (Ruskin, January 23, 2004). The new program will set a TAC, allocate shares among the fishing sectors based on historical community participation in crab fisheries, provide for binding arbitration, allow voluntary cooperatives, increase the CDQ allocation, create a comprehensive data collection and monitoring program, and provide for captain and crew shares and loans to facilitate exit and entry to the fishery. The most controversial element of the plan is a proposed allocation of 90 percent of the TAC as processor shares (NPFMC 2002c). Critics are concerned that an allocation of shares to processors will put fishermen in a compromised bargaining position regarding delivery and price. Proponents of the program state that reduced capacity would aid declining crab stocks by setting a firm TAC, reducing catch overages that occur under current guidelines, and reduce discards and discard mortality by eliminating the derby nature of the fishery (NPFMC 2002c).

Russian fishery management structures have been continuously evolving since the dissolution of the Soviet Union. National programs stress increasing fishery production and earning hard currency to reduce the need for government subsidies to management agencies and the fishing industry, and to assist in repairing social support structures that were disrupted by the collapse (Pautzke 1997).

In U.S. King Crab fisheries, bycatch is comprised of females of all target species, sub-legal males of target species and non-target crab species (NPFMC 2000). No quantitative estimates of bycatch are available for Russian fisheries.

In U.S. waters federal and state managers have adopted numerous regulations intended to minimize crab bycatch in both crab and groundfish fisheries. Crab fishery regulations include minimum mesh size limits, area closures, and the required use of degradable escape or timed release mechanisms on pot gear (NPFMC 1998a). King Crab are identified as prohibited species in the groundfish trawl fishery and are protected through the use of area closures and prohibited species caps (NPFMC 1998b). Also, the Pribilof Islands Red King Crab fishery remained closed in 2001 and 2002 partially due to concerns about the incidental catch of Blue King Crab (NPFMC 2002a).

Russia has established bycatch limits for each species and requires the fishing industry to reimburse the state for discards. Bycatch of females and subadults in directed crab fisheries is limited to 0.2% per day. Crab bycatch in trawl and other fisheries is limited to 2% per day (Pautzke 1997) and areas in the Sea of Okhotsk have been closed to trawling to protect king crab (FAO 1997).

Some estimates of bycatch of crabs in other fisheries are available. For example, in 1999, less than 1% each of Bristol Bay red king crab, St. Matthew blue king crab and Bering Sea snow crab populations were taken as bycatch in all fisheries occurring in those respective management areas (NPFMC 2000).