Assessment and advice of Snow Crab in West Greenland 2009. Technical Report No. 74

By An Assessment and advise of snow crab in west Greenland 2009 nDorte Burmeister a Helle Siegstad By AnnDorte Burmeister TEKNISK RAPPORT NR. 74, 2008 Snow crab stock status and advisory report 2009 2 Titel: Assessment and advice of Snow Crab in West Greenland 2009 Forfatter(e): AnnDorte Burmeister Serietitel og nummer: Teknisk rapport nr. 74 Udgiver: Pinngortitaleriffik, Grønlands Naturinstitut Udgivelsestidspunkt: November 2008 Kvalitetssikring: Earl Dawe, Department of Fishery and Science, Newfoundland, Canada Oversættelse: Finansiering: Forsidefoto: AnnDorte Burmeister ISBN: 87-91214-38-6 ISSN: 1397-3657 Bedes citeret: Burmeister, AD. 2008. Asessment of snow crab in West Greenland 20089 Teknisk Rapport nr.74, Pinngortitaleriffik, Grønlands Naturinstitut Rekvireres: Rapporten er udelukkende udgivet elektronisk. PDF-fil af Rapporten findes på instituttets hjemmeside http://www.natur.gl/publikationer/tekniske rapporter Det er muligt at rekvirere en udskrift af rapporten her: Pinngortitaleriffik, Grønlands Naturinstitut Postboks 570 3900 Nuuk Grønland Tlf. +299 36 12 00 Fax. +299 36 12 12 [email protected] www.natur.gl T68nisk rapport nr. 68, 2007 Pinngortitaleriffik, Grønlands Naturinstitut Snow crab stock status and advisory report 2009 3 Assessment and advice of Snow Crab in West Greenland 2009 AnnDorte Burmeister, Pinngortitaleriffik, Greenland Institute of Natural Resources. Box 570, 3900 Nuuk. Greenland. Phone: +299 361200. E-mail: [email protected]. Introduction This report documents the scientific basis for the assessment of snow crab (Chionoecetes opilio) stocks in West Greenland. Snow crabs are patchily distributed and commercially exploited along the coast and within the fjords. The fishery is managed by quotas and assessed when data are available within the inshore and offshore of 6 management areas (Upernavik, Uummannaq-Disko Bay, Sisimiut, Maniitsoq-Kangaamiut, Nuuk-Paamiut and Narsaq-Qaqortoq. The report briefly updates and summarizes the historical background of commercial crab fishing, which includes catch, effort, CPUE and spatial distribution of the fishery, as well as the results from scientific surveys undertaken by the Greenland Institute of Natural Resources (GINR). Summary There are no specific long-term management objectives for the snow crab resource in West Greenland, however since 2004 the main objective of recommendations from GINR has been to stop the decline in biomass of the crab resource in the different management areas. The recommended catch level for 2009 in Disko Bay inshore is 600 tons and identical with the total commercial catch in 2007. The quota should be divided on 200 tons in the southern part of Disko Bay, 200 tons in the Northern part of the bay and 200 tons in Vaigat. The TAC is reduced with 60% compared to 2008. Data obtained by logbooks and landings indicates that the quota has never been fully taken. The catch has never been regulated, but the fishery has been self regulating. Despite a big decrease in removals by the fishery, both commercial and survey CPUE has only increase a little and very gradually. Data from research survey in the Northern part of Disko Bay suggest some progression in the forthcoming recruitment to the resource, but will not be available to the fishery before 2010. An increase in catch in 2009, above 600 tons, could impose high handling mortality on soft/shelled crabs that would harm the forthcoming recruitment. The recommended catch level for 2009 in Sisimiut inshore is 500 tons, divided on 300 tons in the traditionally fishing area and 200 tons in Ndr. Isortoq and Ndr. Stoemfjord. Data from research survey in Sisimiut inshore suggest progression in the CPUE index and forthcoming recruitment to the resource. Also fishery data obtained by logbooks showing progression in the commercial biomass. The recommended catch level for 2009 in Sisimiut offshore is 300 tons. However caution must be taken while forthcoming recruitment still are at a low level. Harvesting should be monitored using a precautionary approached, relayed on approach for changes in catch levels, careful monitoring of the populations response to the fishery and implementation of re-open /re-closure criteria Snow crab stock status and advisory report 2009 4 Data from research survey as well as data obtain from logbooks for Sisimiut offshore suggest that the resource has shown signs of recovery for the past 3 years, except for recruitment which is on a low level. The recommended catch level for 2009 in Nuuk – Paamiut inshore is 700 tons, and unchanged from 2008. The recommended catch level for 2009 in Nuuk - Paamiut offshore is 1,600 tons, and unchanged from 2008. Due to the lack of survey and fishery data no recommendation is given for ManiitsoqKangaamiut inshore and offshore. GINR recommends a seasonal fishery from April to July in all management areas to reduce discarding and associated mortality to soft-shelled crabs and to maximize recruitment to the stock. Such a seasonal fishery will also promote the most optimal and sustainable utilization of the crab resource. Resource status in each management area derived from fishery data An overview of GINR‟s recommendations and the imposed quota and fishing status (open or closed) of the management areas in 2009 are given in Table 1. Table 1. Summary of catch recommendations for the crab fishery in 2009 from the Greenland Institute of Natural Resources and total catch from 2007 (catch statistics for 2008 are incomplete at this time). Recommended catch Inshore 2009 in tons Recommended catch Offshore 2009 in tons Catch in tons 2007 Inshore Catch in tons 2007 Offshore Disko Bugt 600 130 574 123 Sisimiut 500 300 559 225 Maniitsoq No advice No advice 13 174 Nuuk-Paamiut 700 1,600 111 410 Recommended catch in all 1,800 2,030 1,257 932 Snow crab stock status and advisory report 2009 5 Species biology Snow crab habitat include sites were bottom is covered by mud/sand and rock. Their diets include brittle stars, shrimp, younger stages of snow crab (cannibalism), clams, polychaete worms and other crustaceans. Predators are various groundfish, snow crab and human. Snow crab hatching their broods in spring and larvae undergo two planktonic larval stages and settle to bottom during fall. Benthic juveniles snow crab males as well as females molt frequently and become sexually mature from > 50 mm carapace width (CW) depending on bottom temperature. Snow crabs tend to molt during spring and continue until terminal molt at adulthood is reached within a size range of 50 – 130 mm CW for males and 40 – 95 mm CW for females. At the terminal molt males developing enlarges claws improving their mating ability. Only a portions of any given cohort recruit to the fishery at 100 mm CW, where the males is approx. 8 to 9 years. After the molt to adulthood legal sized males remain soft/new shelled having low meat yield for the rest of the year. In the following year, meat yield would have increased to a suitable level for the industry. Discard of soft shell and new-shelled, due to their low yield contents is resources wastage. Historical fishery background Snow crabs are distributed along the West coast of Greenland and are commercially exploited primarily from Disko Bay in the North (up to 71 30N) to Paamiut in the South (60 45N). The commercial crab fishery is based on catches of males that reach a minimum legal-size ≥ 100 mm carapace width (CW). Commercial fishery for snow crab began primarily in inshore areas (within basis-line) in the mid-1990s and from 1999, also included offshore areas (outside basis-line). Since 2004, the crab resource in Greenland has been managed in 6 areas (from North to South - Upernavik, Uummannaq-Disko Bay, Sisimiut, Maniitsoq-Kangaamiut, Nuuk-Paamiut and Narsaq-Qaqortoq, see Fig. 1). The fishing fleet is made up of two components; small vessels (less than 75 GRT), which have exclusive rights for fishing inshore within the basis-line as well as offshore. Small vessels are, however, restricted to fishing in only 1 management area during the year. Large vessels (greater than 75 GRT) may only fish in all offshore areas (outside the basisline), but not within the “Crab Boxes”. Total allowable catch (TAC) restrictions have been imposed since 1995, but have only limited the catch in some areas since 2004. The fishery is regulated by prohibitions to land females and undersized males (<100 mm CW), logbooks for all vessels larger than 10 meters and closure of the fishery north of 64°N for 3 months (1 January to 31 March). There is also a regulation that states movement of the fishing effort when soft-shelled crabs exceed 20% of the catch, however the term “movement” is not specific and this is not monitored. From 2005 to 2007, the offshore crab fishery was closed in the management areas Maniitsoq-Kangaamiut and from 2005 to August 2007 in the offshore area of Sisimiut except for dispensation to 1 vessel that was allowed to fish in 2005. In 2006, the fishery was closed for 2½ months (July 1 to September 15) in all areas except Uumannaq-Disko Bay (closed only 1 month from July 1 – August 3) to protect softshelled crabs. The number of vessels with licenses to participate in the snow crab fishery increased by more than a factor of 3 from approx. 120 to 374 boats from 1999-2002. Since then the number of both large and small vessels have decreased substantially as the abundance of the resource has also declined. In 2008 the number license holders amounted 74 in all management areas an 80% reduction compared to 2002. Snow crab stock status and advisory report 2009 6 The Greenland Institute of Natural Resources (GINR) gives stock assessment and management advice for the stock both inshore and offshore within each management area when sufficient data is available. The decision to give advice for both inshore and offshore areas was based on the assumption that snow crab migration is limited (tagging studies have indicated approx. 10 km per year) and therefore the resource in different areas is considered to be spatially independent. Commercial fishery data Logbooks from the large vessels >75 GRT have been mandatory since 1999 in conjunction with the start of offshore fishing with vessels of this size. Logbooks for the small vessels (<75 GRT) were first mandatory from July 2002, and thus first covered the annual fishery in 2003. Only landing statistics are available from boats less than 10 meters as they are not required to report catches in logbooks. Catch, Effort and CPUE The historical development of the crab fishery in Greenland is shown in Figure 2. The overall annual catches are based on landings, because catch statistics from logbooks for both small and large vessels have only been available since 2003 and are not always complete. Landings increased from approx. 1,000 tons (no TAC) in 1995 to a peak of approx. 15,000 tons (TAC 26,800 tons) in 2001 (based on landings from small vessels and catch from logbook data from large vessels >75 GRT). From 2001 to 2007 the total catch has decreased by approx. 89% to 2,189 tons (TAC 4,380 tons) despite the quota was not being reached (Fig. 2). The distribution of the landings in each management area in Fig. 3 and Fig. 4, show that traditionally, most of the landings have predominately come from the areas Disko Bay-Uummannaq, Sisimiut and Nuuk-Paamiut. Commercial CPUE is derived from catch and effort data from logbooks. The total fishing effort (trap hauls) has declined by 81% since 2001 (from 3,416 to 665 thousand trap hauls during 2001-2007) (Fig. 3). The decline has been mostly due to a declining number of participants in the fishery. Preliminary and incomplete logbook data for 2008 shows total effort is 240 thousand trap hauls. The ratio of total landings to logbooks landing varies between management areas. The overall distribution of the fishery along the West coast of Greenland from 2003-2007, derived from available logbook data is shown in Figure 4. Research Surveys Since 1997, trap surveys have been conducted annually in inshore areas of Disko Bay and Sisimiut. In 2000, a Sisimiut offshore area (Holsteinsborg Dyb) was included in the Sisimiut trap survey. In 2002, annual offshore trap surveys were initiated in areas between Nuuk and Paamiut and in 2003 were extended north to include the offshore in the Maniitsoq-Kangaamiut management area. Methods Snow crabs are sampled with Japanese-style conical traps with large (70 mm) and small (21 mm) mesh sizes. Sampling stations are at predetermined fixed positions for all years and soak times range between 14-24 hrs depending on weather conditions. Bottom temperatures are recorded at each station. For males, the carapace width (CW) and chela height (CH) are measured (± 0.01 mm) to determine size and molt status (adolescent or adult). Male snow crabs stop growing after their terminal moult. Sexually mature males are referred to as an adolescents (recognized by their small claws) prior to the terminal molt and as adults after their terminal molt (large claws). Males reach legal size ( 100 mm CW) at about 9 years of age. The range of carapace widths defining the adolescent male groups which are presumably 1, 2 and 3 Snow crab stock status and advisory report 2009 7 years from recruitment to legal size are: ADO-1, 82.2-100mm CW; ADO-2, 67.3-82.2mm CW and ADO-3, 53.2-67.3mm CW. For females, the CW and abdomen width (AW) are measured (± 0.01mm) to determine size and maturity. Females that have mated once and are carrying their first clutch of eggs are called primiparous, while females that are carrying their second clutch and have mated more than once are called multiparous. They are distinguishable by the number of scars on their legs caused by mating and by shell conditions. Shell condition in both males and females is determined on a scale of 1-5 according to guidelines by Sainte-Marie (1993). Data from trap survey catches of males are used to determine CPUE (kg/trap), mean CW of legalsize males, shell condition and NPUE (number- /trap) of adolescent males to assess recruitment prospects. Male and females size distributions are also described to follow the progression of size modes through the populations and determine primiparous/multiparous ratios within the female population. Inshore surveys in Disko Bay and Sisimiut In Disko Bay, 43 stations are sampled annually (Fig. 5a) and in Sisimiut, 40 stations are sampled (Fig. 5b), from May to June. The sampling gear consists of a longline of 10 large-mesh (70mm) and 2 small-mesh (21mm) conical traps fished at depths ranging from 100-600m. Traps are placed approx. 40m apart and baited with squid. Offshore surveys in Sisimiut, Maniitsoq and NuukPaamiut Fifteen stations are sampled annually in Sisimiut offshore (Fig. 5b) in June and a total of 30-60 stations are sampled in the Nuuk-Paamiut and Maniitsoq offshore areas in August-September (Fig. 5c). The sampling method in Sisimiut offshore is the same as the method used inshore in Disko Bay and Sisimiut. In 2002, the sampling in the Nuuk-Paamiut offshore survey was also the same as the method inshore. In 2003, however, the offshore sampling method used in Nuuk-Paamiut and Maniitsoq was changed such that each station was then sampled using a longline of 16 traps, eight large-meshed (70 mm) traps alternating with eight small-meshed (21mm) traps at approx. 40 m intervals and baited with squid. Input data from commercial fishery to assessment No sampling from the commercial fishery has been conducted since the fishery began in 1996. Available logbook and landing statistics is used in data analysis from the commercial fishery. Logbooks nominal catches has since 2003 covered more than 85% of the total landings in Greenland. Before 2003 less than 20% of the fishing fleet were using logbooks. In order to calculate a standardised CPUE index, a GLM analysis (multiadditive model) was carried out using haul by haul logbook information including zero catches. The model includes year, month and vessel effects. Snow crab stock status and advisory report 2009 8 Management area: Uummannaq-Disko Bay The historical catch, CPUE and effort data for the fishery in Uummannaq-Disko Bay in the inshore and offshore areas are summarized in Table 2. Data for 2008 are preliminary. One of the most important fishing areas has been Disko Bay where catches are predominately from the inshore. Total catches peaked at 4,202 tons (94% inshore) in 2001 and since then have steadily declined to 697 tons (82% inshore) in 2007, approximately 15% of the 2001 catch. Inshore - Disko Bay Fishery The distribution of the fishery in Disko Bay from 2003 to 2008, according to available logbook data is shown in Figure 6. Fishing grounds include both Vaigat, area “Disko Nord” and “Disko Syd”. The geographic distribution of the fishery has been homogeneous in the period from 2003 to 2007, were only used effort has changed markedly. In 2008 preliminary data indicate no or only a very limit fishery in the area “Disko Syd”. The fishery in Disko Bay typically starts in April, peaks during the summer months (June-July) and steadily declines towards the end of the year, except in 2003 when the fishery peaked in March and May. In 2006 the fishery peaked in September, mainly due to a closure during July and August. Monthly trends in the fishery CPUE in 2006 stable from September to December at approx. 5 kg /trap, whereas the CPUE staidly decreased at the end of the year in the previous years (Fig. 7). 2007 were almost following the trend as in 2006, except for a decline of 50% in CPUE from October to December. Early season catch rates (Mar-May generally decreased over tome (2004-2007), perhaps because early season focused on traditional areas. Late season CPUE increased from 2004-2006, reflecting allocation of effort to new areas as the season progressed. A standardised CPUE index (Fig. 8), show a significant dropped in CPUE from 2000 to 2001 from approx. 7 kg/trap to 3.1 kg/trap (F= 85.53, P < 0.000). In the following years CPUE has remained low at a stable level. Preliminary data for 2008, representing approx. 14% of the allowable quota, indicate increasing trends in CPUE (Table 2) and (Fig. 8). From 2000-2001 catches inshore increased from 2,940-3,950 tons as effort more than doubled (613-1274 thousand trap hauls, Table 2). Catches and effort have steadily decreased since 2001 by approx. 74% to 574 tons and 138 thousand trap hauls, respectively, in 2007 (Table 2 and Fig. 8). Standardised soak time index (Fig. 9), shows a significantly decrease in soak time from 2001 to 2002. Since 2003 soak time increased steadily until 2007, at a level of average 72 hour per hauls and comparable to 2001 level. Research Surveys Inshore (South and North) In 2008 survey was only conducted in the Northern part of Disko Bay. Trap surveys have been conducted in 2 inshore areas of Disko Bay since 1997 (See Fig. 5a for maps), despite in 2008 where only the subarea North, were investigated. CPUE of legal-size males ( 100mm CW) in South and North peaked in 2001 and 2000 respectively and have declined steadily by more than 50% to 2004; from 4.2-1.7 kg/trap in South and 7.5-2.3 kg/trap in North (Fig. 10). The 2004 CPUE was the lowest observed in the time series. In 2005 and 2006 CPUE in South was still considerably below the reference mean of 3.7, but increased to 4 kg/trap, marginally above the reference mean, in 2007. In North, CPUE increased from 2.3 to 6.4 kg/trap and has reached the reference mean in 2006. In 2007 CPUE decreased to 4.4 kg/trap and only a very small increase to 5.1 kg/trap was observed in Snow crab stock status and advisory report 2009 9 2008. Reference means are based on the average kg/trap from 1999-2002. The mean carapace width (CW) of legal-size males had continually declined in both survey areas to a minimum in 2004 (Fig. 11). CW subsequently increased in both areas in 2005 and remaining unchanged in South to 2007, while the mean CW has increased over the past 4 years in North to 116 mm CW in 2008 similar to observation from 2007. The abundance of adolescent males (ADO-1), measured as number per trap (NPUE), peaked at 2.2/trap in South in 2001, and 2.6/trap in North in 2002 (Fig. 12). The NPUE of ADO-1 has since declined sharply in both areas and was at the lowest levels observed for the time series in 2004 in South. In 2006, the NPUE of ADO-1 males in South were 0.8/trap and increased in 2007 to 1.8/trap, above the reference mean. NPUE of ADO-1 in North decreased continuously to 1/trap, the lowest levels observed in the time series, from 2001 to 2007, with exception from a increase in 2005.The NPUE of ADO-1 in North increased to 2.1/trap in 2008 and is now above the reference means and close to the highest observation in the time series. Annual trends in size distribution of adolescent and adult males are shown in Fig. 13. In South there was no further progression through the size range until 2006. Data from 2007 implies a recent increase in recruitment caused by increasing recruitment of small legal-sized new-shelled since 2005. In North the recruitment pulse in 2005, resulted in increasing CPUE and mean CW as legal-sided adolescent pre-recruits molted and the „recruitment pulse‟ progressed through the size range. The decrease in ADO-1 males in 2006 showed up clearly as a reduction of adult males in the size range from 100mm to 130mm CW. In North there was progression through the size range in 2007 and 2008. Data from 2008 strongly implies a recent increase in recruitment caused by increasing recruitment of small legal-sized newshelled since 2006. Further more in 2008, the highest proportion of adolescent males from 60 mm to approx. 80 mm CW has been observed in North (i.e. a mix of ADO2 and ADO3, expected to recruit to the fishery with in 2 and 3 years from 2008). In North the recruitment pulse since 2008, didn‟t results in increasing CPUE in the two following years. Increasing proportion of legal-size soft and newshelled males (shell condition 1 and 2) have been observed from 2001-2006 (Fig. 14) and have peaked at around 70% in 2006 in both South and North. The continuously high proportion of soft and new-shelled males suggests a continuous removal of the older shelled males by the fishery, which was becoming increasingly dependent upon recruitment in the years from 2001 to 2006. However, the proportion of soft and new shelled males (shell condition 1 and 2) has decreased to less than 40% in 2008, suggesting that the fishery the past year has been less dependent of the recruitment to the stock in the North. The ratio of primiparous and multiparous females, used to support trends in recruitment, decreased sharply in South from 2000 to 2003, remained low in 2004 and has increased until 2006 and decreased again from 2006 to 2007 (Fig. 15). The increase in South in 2005 and 2006 could either reflect the loss of a large group of mature females from the population or that a recruitment wave could be forthcoming. In 2007 a minor decrease has been observed but is at the 2005 level. In North the ratio of primiparous and multiparous female has remained constant at a level of 0.45 from 2004 to 2006, decreased to 0.26 in 2007. In 2008 the ratio of primiparous and multiparous females increased to approx. 0.5, indicating a recruitment of mature females to the stock. Snow crab stock status and advisory report 2009 16 Outlook - Inshore Maniitsoq-Kangaamiut There are indications that CPUE has slightly increased over the last year, but a decrease from 2006 to 2007. Improvement is, however, small considering the low commercial catch and effort. It is difficult to determine the biomass of the resource in the area as a whole as logbook data from the fishery are limited to a small inshore area in the northern part of Maniitsoq-Kangaamiut. There is no survey in the inshore area so comparative biomass and recruitment prospects are unknown. Recommendations for the 2009 fishery - Inshore Maniitsoq-Kangaamiut Due to the lack of survey and fishery data no advice is given for Maniitsoq-Kangaamiut inshore. Offshore Maniitsoq-Kangaamiut Fishery Catches in Maniitsoq-Kangaamiut offshore increased from 381 to 826 and 743 tons from 2000 to 2001 and 2002, respectively as effort increased from 50 to 275 thousand trap hauls. CPUE during the same period was originally 7.6 kg/trap in 2000 but decreased substantially to 2.7 kg/trap in 2002 suggesting the resource biomass was negatively affected by the increase in the fishery. In 2003 the catches declined by 41% (445 tons) as effort decreased by 44%. Despite these reductions the CPUE remained low at 2.8 kg/trap. In 2004 CPUE decreased further to 2.1 kg/trap despite a further 76% drop in catches indicating the resource was still in a state of decline. The continued poor state of the resource biomass and confirming data from a biological survey led to the recommended and implemented closure of the offshore area in 2005 and again in 2006 to promote the recovery of the resource. Some fishery has, however, taken place and shows CPUE was 4.3 kg/trap at a catch of 12 tons in 2006. The management area has benne closed in 2005 and 2006, but was reopened with a quota on 200 tons in August 2007. In 2007 CPUE has increased to approx. 10.2 kg/trap, as well as catches and effort increased to 174 tons in 2007 and effort to 17 hundred thousand used taps. Preliminary catch for 2008 is 107 tons. No standardised index of CPUE and soak time has been prepared, owing to the lack of data and un-regularly recurring fishery in this area. Research Surveys Owing to the breakdown of the main engine at the research ship Adolf Jensen, the survey has been cancelled in 2007 and 2008. No new survey data is available for the stock assessment and advice. Outlook - Offshore Maniitsoq-Kangaamiut Fishery data is very sparse and those available suggest an increase in CPUE along with a large reduction in catch since 2004. Recommendations for the 2009 fishery - Offshore Maniitsoq-Kangaamiut No new data are available for 2008. Due to the lack of survey and fishery data no advice is given for Maniitsoq-Kangaamiut offshore. Management area: Nuuk-Paamiut The historical catch, CPUE and effort data of the fishery in Nuuk-Paamiut inshore and offshore areas are summarized in Table 2. The Nuuk-Paamiut area has been an important fishing area where total catches peaked at more than 5,000 tons in 2001. However, catches the following year were approximately 50% lower (2,531 tons) despite only a 10% decrease in effort. This led to the fishery CPUE inshore and offshore decreasing from 5.3 and 3.8 kg/trap respectively in 2001 to 2.8 kg/trap in 2002 in both areas,. Total catches including inshore and offshore have been somewhat stable around Snow crab stock status and advisory report 2009 17 2,300 tons during 2002-2005, partly as a result of low overall effort and more recently due to quota restrictions. Total catches decreased by 77% to 521 tons in 2007 (410 tons offshore and 111 tons inshore). Catches have been steadily declining concurrent with a reduction in effort, which has been moving offshore until 2005 (Fig.32). Inshore - Nuuk-Paamiut Fishery Catches peaked at 4,157 tons in 2001 and then declined by more than 97% to 111 tons in 2007 (Table 2 and Fig. 33), while fishing effort declined by 98%. Preliminary commercial data in 2008 shows a CPUE of 8.2 kg/trap at a catch of 72 tons. The distribution the fishery in 2004 and 2006 has been concentrated near the middle of the management area in sub-areas FiskenæsDanasdyb and Frederikshåb-Ravnsdyb. There is, however some fishery in the northern part of the area – Godthåb (Fig. 32). From the standardised CPUE index (Fig. 33) it appears that CPUE has gradually increased during this period from a low of 2.8 kg/trap in 2002 to 7.7.4 kg/trap in 2006, but decreased to 6.8 in 2007, despite a 37% reduction in effort (Table 2). Soak time has gradually increased from 2003 to 2005 and had since varied. In 2007 average soak time was approx. 87 hour per hauled traps fleet (Fig. 34). Outlook - Inshore Nuuk-Paamiut There is no survey undertaken in Nuuk-Paamiut inshore thus recruitment indices and other biological parameters are not available. The commercial CPUE increased to 2007 as total catch and effort decreased but some concern regarding sustainability of the resource at higher catch levels, due to the lack of biological data. Recommendations for the 2009 fishery - Inshore Nuuk-Paamiut There had been indications of improvement to the resource biomass over the last several years in a scenario of decreasing fishing exploitation. It is however, difficult to determine the extent of the improvement due to the lack of other stock indices. It is therefore recommended that the catch level of 700 tons for 2009. Offshore - Nuuk-Paamiut Fishery The distribution in the offshore fishery has changed slightly in recent years from a continuous distribution of effort along the inner edges of the offshore banks from the middle of the NuukPaamiut area and northward in 2003 to effort concentrating around the middle of the NuukPaamiut (sub-areas Fiskenæs-Danasdyb and Frederikshåb-Ravnsdyb) in 2004 and 2007 (Fig. 32). Only in 2005 and 2006, effort has been allocated to a fishery along the outer edges of the banks (Fyllas bank) in the northern part of NuukPaamiut. From 2000-2002, catches in Nuuk-Paamiut offshore declined from 1,339 to 761 tons (Table 2 and Fig. 35). Catch more than doubled to 1,611 tons in 2003 and further increased to 2,033 tons as effort decreased to 302 thousand trap hauls in 2005. In 2006 the catch decreased to 969 tons and has been gradually declining to 410 tons in 2007, which was not limited by the quota of 1,600 tons. Effort decreased by 81% from 2005 to 2007. In 2007 there were no landings of crab from ultimo June to mid October 2007 to the main industry component (Royal Greenland) in Paamiut. Preliminary catch is 292 tons for 2008. Standardised CPUE gradually increase from 3.8kg/trap in 2001 to 7.9 kg/trap in 2005 (Fig. 35). For the past two years CPUE declined to 5.1 kg/trap. Preliminary data for 2008 show a CPUE of 7.7 kg/trap. Snow crab stock status and advisory report 2009 18 Monthly trends in commercial data generally show substantial declines in both catches and CPUE during the year, suggesting the resource is being depleted considerably as the fishing season progresses. The fishery starts in January and has the highest catch rates from February to May. CPUE steadily declines during remainder of the season (Fig. 36). The Feb-May data indicate that early-season CPUE in 2007 was comparable to that in 2006, at a lower level than during 20042005. Soak time has been quite stable and varied from 63 to 77 hour per hauled trap fleet from 2001 to 2007. Average soak time in 2008 is 61 hour approx. 87 hour per hauled traps fleet (Fig. 36). Research Surveys Owing to the breakdown of the main engine at the research ship Adolf Jensen, the survey has been cancelled in 2007 and 2008. No new survey data is available for the stock assessment and advice. Outlook - Offshore Nuuk-Paamiut No new survey data has been available for the past two years. The commercial catches have gradually declining. It is uncertain if reduction is a consequence of a low biomass or lack of interest for commercial snow crab fishery in the management area. Recommendations for the 2009 fishery - Offshore Nuuk-Paamiut No new biological data has been available since 2006. CPUE has remained stable at around 7 kg/trap since 2005 despite a drop in 2006 and a decline with approx. 80% in catches from 2005 to 2007. To take into consideration recruitment uncertainties, it is recommended that the catch level for 2009 does not exceed 1600 tons, identical with the quota for 2007 and 2008. Special comments Owing to the cancelled survey in 2007 and 2008, there is no fishery-independent data, to validate the apparent decrease in the exploitable biomass in this area. Snow crab stock status and advisory report 2009 19 Management Area Year Total catch (tons) Quota Inshore catch (tons) Inshore CPUE (kg/trap) Inshore effort ('000) Offshore catch (tons) Offshore CPUE (kg/trap) Offshore effort ('000) 2000 -- -- -- -- -- -- -- -- 2001 -- -- -- -- -- -- -- -- Upernavik 2002 -- -- -- -- -- -- -- -- 2003 -- -- -- -- -- -- -- -- 2004 65 -- -- -- -- -- -- -- 2005 -- 100 -- -- -- -- -- -- 2006 0 2007 -- 0 -- -- -- -- -- -- 2008* -- 0 -- -- -- -- -- -- 2000 3,052 -- 2,940 4.8 613 112 5.5 20 2001 4,202 -- 3,950 3.1 1,274 252 3.6 70 Uummannaq-Diskobugt 2002 3,319 -- 2,970 3.3 900 349 3.0 116 2003 2,739 -- 2,482 3.7 679 257 2.6 97 2004 2,341 -- 2,174 3.4 632 167 3.7 45 2005 1,500 1718 1,404 3.9 363 96 4.0 24 2006 1,134 1600 1,008 4.6 221 126 6.7 19 2007 697 1530 574 4.2 138 123 5.1 24 2008* 246 1400 189 5.1 37 57 5.2 11 2000 2,534 -- 491 2.8 175 2,043 6.4 319 2001 2,602 -- 327 2.9 113 2,275 4.6 495 Sisimiut 2002 2,724 -- 473 4.6 103 2,251 3.5 643 2003 1,633 -- 692 3.7 187 941 3.1 304 2004 1,432 -- 1,111 3.9 286 321 4.9 65 2005 1,125 900 891 6.5 137 234 6.4 37 2006 736 750 725 8.3 87 11 11.1 1 2007 784 850 559 7.4 75 225 12.8 18 2008* 414 800 365 10.0 36 49 12.1 4 2000 944 -- 563 4.3 131 381 7.6 50 2001 1,835 -- 1009 3.7 273 826 5.0 165 Maniitsoq-Kangaamiut 2002 1,775 -- 1032 3.8 272 743 2.7 275 2003 485 -- 40 3.5 12 445 2.8 160 2004 116 -- 78 2.4 33 38 2.1 18 2005 73 200 (inshore) 62 4.2 15 11 3.6 3 2006 72 100(inshore)' 61 4.3 14 11 4.3 3 2007 187 300 13 2.9 5 174 10.2 17 2008* 115 300 8 5.9 1 107 10.7 10 2000 3,769 -- 2,430 5.3 458 1,339 5.4 248 2001 5,077 -- 4,157 5.3 784 920 3.8 242 Nuuk-Paamiut 2002 2,531 -- 1,770 2.8 632 761 2.8 272 2003 2,315 -- 704 3.4 207 1,611 4.2 385 2004 1,795 -- 180 4.5 40 1,615 8.0 203 2005 2,295 -- 262 8.0 33 2,033 6.7 302 2006 1,173 1,800 204 7.3 28 969 3.0 328 2007 521 1,600 111 7.2 15 410 7.4 56 2008* 364 1600 72 8.2 9 292 9.3 31 2000 2 -- 0 -- -- 2 -- -- 2001 822 -- 822 -- -- 0 -- -- Narsaq-Qaqortoq 2002 643 -- 642 -- -- 1 -- -- 2003 133 -- 123 -- -- 10 -- -- 2004 541 -- 32 3.9 8 2 1.0 2 2005 76 -- 76 8.3 9 -- -- -- 2006 0 -- -- -- -- -- -- -- 2007 0 -- -- -- -- -- -- -- 2008* 0-- -- -- -- -- -- -- Tables Table 2. Catches, catch rates (CPUE) and effort in management inshore and offshore areas from 20002008. *2008 data is preliminary and incomplete. Snow crab stock status and advisory report 2009 20 Figures Fig 1. Map of West Greenland outlining the 6 management areas as of 2004 for the snow crab fishery. Snow crab stock status and advisory report 2009 21 Year 1996 1998 2000 2002 2004 2006 2008 Qouta and total catch (000' tons) 0 5 10 15 20 25 30 35 Qouta Total catch Figure 2. Total catch and quota size from 1995-2007. Data from 2008 is only preliminary. Fig. 3. Snow crab landings in the 4 most important management areas of West Greenland 2000-2008 and used total effort. Data for 2008 are preliminary and incomplete. Year 2000 2002 2004 2006 2008 Total catch (tons) 0 2000 4000 6000 8000 10000 12000 14000 16000 Total effort ('000) 0 1000 2000 3000 4000 Disko Bay - Uummannaq Sisimiut Maniitsoq - Kangaamiut Nuuk - Paamiut Total effort Snow crab stock status and advisory report 2009 22 Fig. 4. Distribution of the crab fishery off West Greenland within each management area from 2003 - 2008, derived from logbook data. Lines are used to separate management areas. 2003 2004 2005 2006 2007 2008 Snow crab stock status and advisory report 2009 23 LL LG LH LJ LK LS LM LN LP LR LA LB LD LE LF 13 14 1715 16 18 19 24 20 21 22 23 29 25 26 27 28 3430 31 32 33 Qeqertarsuaq Aasiaat Qasigiannguit Ilulissat 61 62 63 6465 66 67 68 69 70 71 72 73 74 76 77 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 98 99 175 176 177 178 KF KG KH KJ 14 KA KB KD KE 13 1815 16 17 19 20 21 22 Sisimiut 51 52 54 55 58 60 25 26 27 28 29 32 33 34 17 18 19 20 21 1 2 3 4 5 6 7 8 9 10 11 12 35 42 44 45 46 47 48 49 50 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 Fig. 5a. Map showing the location of survey stations in Disko Bay, Area 1 (North) and Area 2 (South). Fig. 5b. Map showing the location of inshore and offshore survey stations in Sisimiut. Snow crab stock status and advisory report 2009 24 Maniitsoq-Kangaamiut Fiskenæs-Danasdyb Godthåb Nuuk-Paamiut Frederikshåb-Ravnsdyb L J M I H K NUUK G C D E F A B NUUK Offshore Survey Areas Maniitsoq-Kangaamiut Nuuk-Paamiut 0 0 Fig. 5c. Map showing the location of survey stations from Maniitsoq-Kangaamiut and Nuuk-Paamiut (and sub-areas). Snow crab stock status and advisory report 2009 25 Fig. 6. Annual distribution of fishing effort in Uummannaq-Disko Bay from 2003-2008. Data for 2008 is preliminary and incomplete. 2003 2004 2005 2006 2007 2008 Snow crab stock status and advisory report 2009 32 Fig. 14. The percentage of shell conditions (1-5) of adult legal-sized male crabs ( 100mm CW) sampled in Disko Bay South and Disko Bay North, Disko Bay 1998 to 2008. Fig. 15. Annual trends in the ratio between primiparous and multiparous in Disko Bay South and Disko Bay North, Disko Bay 2000-2008. Disko Bay - South Year 1998 2000 2002 2004 2006 2008 Percent (%) 0 20 40 60 80 100 Disko Bugt - North Year 1998 2000 2002 2004 2006 2008 Percent (%) 0 20 40 60 80 100 SC1 SC2 SC3 SC4 SC5 Disko Bay - North Year 1998 2000 2002 2004 2006 2008 Primiparous female : (primiparous + multiparous) 0.0 0.2 0.4 0.6 0.8 1.0 Disko Bay - South Year 1998 2000 2002 2004 2006 2008 Primiparous female : (primiparous + multiparous) 0.0 0.2 0.4 0.6 0.8 1.0 Snow crab stock status and advisory report 2009 33 Fig. 16. The distribution and crab fishery in Sisimiut inshore and offshore in 2003 - 2008. The coastal line indicates the basisline separating the offshore from the inshore. Data from 2008 is preliminary and incomplete. 2003 2004 2003 2005 2006 2007 2008 Snow crab stock status and advisory report 2009 34 Inshore Sisimiut Month 0 2 4 6 8 10 12 CPUE (kg/trap) 0 2 4 6 8 10 12 14 16 2003 2004 2005 2006 2007 2008 Fig. 17. Monthly trends in CPUE (kg per trap) from the fishery in Sisimiut inshore from 2003 to 2008. Data for 2008 is incomplete. Inshore Sisimiut Year 1998 2000 2002 2004 2006 2008 CPUE (kg/trap) 0 2 4 6 8 10 12 Total catch (tons) 0 500 1000 1500 2000 2500 CPUE (kg/trap) Upper confidence limit Lower confidense limit Total catch Fig. 18. Standardised CPUE index and total catch based on logbook information inshore Sisimiut from 20002008. Data for 2008 is incomplete. Snow crab stock status and advisory report 2009 35 Inshore Sisimiut Year 1998 2000 2002 2004 2006 2008 GLM index soake time (hour) 0 20 40 60 80 100 120 lsmeans fishtime Upper confidence limits Lower confidence limits Fig. 19. Standardised soak time index based on logbook information inshore Sisimiut from 2000-2008. Data for 2008 is incomplete. Sisimiut inshore Year 1996 1998 2000 2002 2004 2006 2008 CPUE (kg/trap) 0 5 10 15 20 25 CPUE (kg/trap) CPUE in the reference period Lower confidence limits Upper confidence limits Fig. 20. Annual trends in CPUE (kg/trap S.E.) of legal-size males ( 100mm CW) from trap surveys in Sisimiut inshore from 1997 to 2008. The mean CPUE for the reference period (1999-2003) in Sisimiut inshore is indicated with a line. Snow crab stock status and advisory report 2009 36 Year 1996 1998 2000 2002 2004 2006 2008 Average carapace width (mm) 110 112 114 116 118 120 Sisimiut inshore Sisimiut offshore Sisimiut - Ndr. Strømfjord Sisimiut inshore - CW in the reference period Sisimiut offshore - CW in the reference period Fig. 21. Annual trends in the mean carapace width (CW) for legal-size males ( 100mm CW) from trap surveys in Sisimiut inshore (1997-2008) and Sisimiut offshore (1999–2008). The mean CW for the reference period (1999-2003) in Sisimiut inshore and (2000–2003) in Sisimiut offshore is indicated with a line. Sisimiut inshore Year 2000 2002 2004 2006 2008 Abundance (NPUE) 0 1 2 3 4 5 6 7 8 ADO1: 82.2 - 100 mm CW ADO1 in the reference period Fig. 22. Annual trends in the abundance NPUE (No. crabs per trap S.E) of adolescent males (ADO-1: 82.2100mm CW) expected to recruit to the fishery the following year in Sisimiut inshore areas from 2000 to 2008. The mean NPUE for the reference period (1999-2003) in Sisimiut inshore is indicated with a line. Snow crab stock status and advisory report 2009 37 Sisimiut inshore Carapace width (mm) 020 40 60 80 100 120 140 160 Adundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (mm) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (mm) 0 1 2 3 4 5 Adolescent males Adult males Sisimiut offshore Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace widht (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Adolescent males Adult males 2000 2001 2002 2000 2001 2002 Snow crab stock status and advisory report 2009 38 Sisimiut inshore Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Adolescent males Adult males Sisimiut offshore Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Adolescent males Adult males 2003 2004 2005 2003 2004 2005 Snow crab stock status and advisory report 2009 39 Fig. 23. Size distribution of adolescent and adult males from surveys in Sisimiut inshore and offshore from 2000 to 2008. Sisimiut inshore Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Adolescent males Adult males Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Sisimiut offshore Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Carapace width (mm) 020 40 60 80 100 120 140 160 Abundance (NPUE) 0 1 2 3 4 5 Adolescent males Adult males 2006 2007 2008 2006 2007 2008 Snow crab stock status and advisory report 2009 40 Fig. 24. The percentage of shell conditions (1-5) of legal-size adult males ( 100mm CW) sampled in trap surveys in Sisimiut inshore and offshore from 2000 to 2008. Sisimiut inshore Year 1998 2000 2002 2004 2006 2008 Primiparous female : (primiparous + multiparous) 0.0 0.2 0.4 0.6 0.8 1.0 Fig. 25. Annual trends in the ratio between primiparous and multiparous females in Sisimiut inshore from 2000 to 2008. Sisimiut inshore Year 1998 2000 2002 2004 2006 2008 Percent (%) 0 20 40 60 80 100 SC1 SC2 SC3 SC4 SC5 Sisimiut offshore Year 1998 2000 2002 2004 2006 2008 Percent (%) 0 20 40 60 80 100 SC1 SC2 SC3 SC4 SC5 Snow crab stock status and advisory report 2009 41 Offshore Sisimiut Year 1998 2000 2002 2004 2006 2008 CPUE (kg/trap) 0 2 4 6 8 10 12 Total catch (tons) 0 500 1000 1500 2000 2500 CPUE (kg/trap) Upper confidence limits Lower confidence limits Total catch Fig. 26. Standardised CPUE index and total catch based on logbook information offshore Sisimiut from 2000-2008. Data for 2008 is incomplete. Offshore Sisimiut Month 0 2 4 6 8 10 12 CPUE (kg/trap) 0 2 4 6 8 10 12 14 16 2003 2004 2005 2006 2007 2008 Fig. 27. Monthly trends in CPUE (kg per trap) from the fishery in Sisimiut offshore from 2003 to 2008. Data for 2008 is incomplete. Snow crab stock status and advisory report 2009 48