CONTENTS Introduction International Sampling Program Continent of Origin Biological Characteristics of the Catches Salmon at Sea Acknowledgements References Cited
Northeast Fisheries Science Center Reference Document 12-24
The International Sampling Program, Continent of Origin and Biological Characteristics of Atlantic Salmon (Salmo salar) Collected at West Greenland in 2011by Timothy F. Sheehan1, Marta G. L. Assunção2, Nick Chisholm3, Denise Deschamps4, Heather Dixon5, Mark Renkawitz1, Ger Rogan6, Rasmus Nygaard7,Timothy L. King8, Martha J. Robertson9, Niall O’ Maoiléidigh6
1 NOAA Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, Massachusetts 02543, USA
2 The Centre for Environment, Fisheries & Aquaculture Science, Salmon and Freshwater Team, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, UK (England & Wales)
3 River Annan Trust Fisheries Office, St Ann's, Lockerbie, DG11 1HQ, UK (Scotland)
4 Ministère des Ressources naturelles et de la Faune du Québec, Direction de la recherche sur la faune, 880, chemin Sainte-Foy, Quèbec, Quèbec G1S 4X4, Canada
5 University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
6 Marine Institute, Fisheries Ecosystems Advisory Services, The Farran Laboratory, Furnace, Newport, Co. Mayo, Ireland
7 Grønlands Naturinstitut, Kivioq 3, 3905 Nuussuaq, DK-3900 Nuuk, Greenland
8 U. S. Geological Survey, Biological Resources Division, Leetown Science Center, 1700 Leetown Road, Kearneysville, West Virginia 25430, USA
9 Fisheries and Oceans Canada, Science Branch, P.O. Box 5667, St. John's, Newfoundland and Labrador, A1C 5X1, Canada
Web version posted October 18, 2012Citation: Sheehan TF, Assunção MGL, Chisholm N, Deschamps D, Dixon H, Renkawitz M, Rogan G, Nygaard R, King TL, Robertson MJ, O’Maoiléidigh N. 2012. The international sampling program, continent of origin and biological characteristics of Atlantic salmon (Salmo salar) collected at West Greenland in 2011. US Dept Commer, Northeast Fish Sci Cent Ref Doc. 12-24; 27 p. Available from: National Marine Fisheries Service, 166 Water Street, Woods Hole, MA 02543-1026, or online at http://www.nefsc.noaa.gov/publications/
Information Quality Act Compliance: In accordance with section 515 of Public Law 106-554, the Northeast Fisheries Science Center completed both technical and policy reviews for this report. These predissemination reviews are on file at the NEFSC Editorial Office.
An important Atlantic salmon (Salmo salar) mixed-stock fishery exists off the western coast of Greenland. This fishery takes primarily one-sea-winter (1SW) North American and European origin salmon that would potentially return to natal waters as mature two-sea-winter (2SW) spawning adults or older. Effective management of the resource on both continents requires annual collection of accurate landings data, continent of origin assignments and biological characteristics data to assess the impact of the fishery on the contributing stock complexes. Data collected during the fishery are also required for use in assessment models to predict pre-fishery abundance of North American and European stocks and to provide fishery managers with catch options required for setting harvest regulations for this mixed stock fishery.
Atlantic salmon were first documented off the coast of Greenland in 1780 and were targeted by a small local inshore gillnet fishery (Jensen, 1990). During the early-1960s an international presence developed in the fishery; in 1965, vessels from Norway, Denmark, Sweden, and the Faroes arrived and introduced an offshore drift-gillnet fishery (Jensen, 1990). Catches increased substantially to a high of 2,689 metric tons (t) reported in 1971 (Figure 1). Tag studies conducted during this period indicated that the Atlantic salmon caught in this fishery did not originate from Greenland, but were of North American and European origin. Due to the concerns that this fishery would have deleterious impacts on the contributing stock complexes, a quota system was agreed and implemented in 1976 (Colligan et al. 2008) and since 1984 these regulations have been established by the North Atlantic Salmon Conservation Organization (NASCO).
Since 1969, a coordinated international sampling program has been undertaken to obtain biological samples from this fishery. From 1969-1981, research vessels were used to obtain samples. Since 1982, international teams of samplers have been deployed throughout Greenland to obtain samples from fish processing plants (when a commercial fishery was allowed), local markets or other vendors from individual communities where Atlantic salmon were being landed. The focus of this sampling program was to collect biological samples and associated data on the catch. Originally, length, weight and scale samples were collected, and individuals were scanned for fin clips, or external/internal tags. The sampling program has continually evolved, and currently tissue samples are also taken for genetic analysis. In addition, it has been possible to collect samples for ongoing international collaborations investigating the marine ecology and persistent decline in salmon abundance in recent years.
The purpose of this paper is to:
- describe the international sampling program;
- present the results from the continent of origin analysis;
- summarize the biological characteristics of the catch from West Greenland during the internal use only fishery of 2011; and
- provide an update on the SALSEA Greenland Program.
The West Greenland Commission (WGC) of the NASCO has agreed regulatory measures for the West Greenland fishery for all years from 1984 to 2012 (with the exception of 1985, 1991, 1992 and 1996). Since 2006 these have been applied as multi-year regulatory measures; the latest measure was established for the period 2009 to 2011 (WGC(09)7) and restricted landings in 2009 to the amount used for internal consumption in Greenland only, which in the past has been estimated to be 20 t; there would be no commercial export of salmon. The regulatory measure would also apply in 2010 and 2011 if the Framework of Indicators (FWI) developed by ICES (ICES 2007) indicated there had been no significant change in the indicators and therefore, that a reassessment of the catch advice would not be required. As the FWI did not suggest that there had been a significant change in the previously provided catch advice in 2010 or 2011, the 2009 regulatory measure was applied to the 2010 and 2011 fisheries.
In 2002, the Organization of Fishermen and Hunters in Greenland (KNAPK) agreed with the North Atlantic Salmon Fund (NASF) to be compensated for not prosecuting a commercial fishery. As part of this agreement, there was an annual opt out date where either party could notify the other party that the agreement would not be implemented for the upcoming fishing season. In 2007, a new agreement between KNAPK, NASF and the Atlantic Salmon Federation (ASF) was signed that effectively extended and revised the 2002 agreement through 2013, retaining the same opt out option and date as the 2002 agreement.
Although the 2011 commercial fishery remained closed and the quota was subsequently set to nil by the Home Rule Government of Greenland, the internal-use-only fishery for personal and local consumption was unaffected. As in the past, the internal-use-only fishery was without a quota limit, but was expected to be approximately 20 t. The opening date of the fishery was set at 1 August 2011 with a closing date of 31 October 2011. The fishery is regulated according to The Government of Greenland Executive Order no. 21 of 10 August 2002.
Under NASCO's West Greenland Sampling Agreement (WGC(11)4), parties to NASCO's WGC agreed to provide staff to sample catches from the internal-use-only fishery for Atlantic salmon in West Greenland during the 2011 season.
The objectives of the program were to:
- continue the time series of data (1969-2010) collected on continent of origin and biological characteristics of salmon harvested in the West Greenland Fishery;
- provide data on mean weight, length, age and continent of origin for input into the North American and European run-reconstruction models;
- collect information on the recovery of internal and external tags; and
- collect additional biological samples from fresh whole fish in support of SALSEA West Greenland or other special samples as requested.
The European Union agreed to provide staff to sample the fishery for a minimum of six person weeks, the United States agreed for a minimum of four person weeks, and Canada for a minimum of two person weeks. Samplers from various countries involved in the program were as follows:
Ministère des Ressources Naturelles et de la Faune
20 Sept - 10 Oct
UK (England & Wales)
29 Aug - 15 Sept
14 Sept - 28 Sept
NOAA Fisheries Service
24 Aug - 10 Sept
NOAA Fisheries Service
5 Sep - 29 Sept
River Annan Trust Fisheries Office
18 Aug - 30 Aug
University of Waterloo
25 Aug - 15 Sept
Individual samplers were deployed during the course of the salmon fishing season to provide the best spatial and temporal coverage of the fishery possible. The coordination of this effort was handled by the USA (NOAA Fisheries Service) with assistance from the Greenland Institute of Natural Resources. Samplers were stationed in four communities representing four Northwest Atlantic Fisheries Organization (NAFO) Divisions (Figure 2): Ilulissat (1A), Sisimiut (1B), Nuuk (1D) and Qaqortoq (1F).
Reported landings were 27.5 t (27.4 t for West Greenland and 0.1 t for East Greenland ICES statistical area XIV)). In the past, non-reporting of harvest was identified by comparing the reported landings to the sample data. From 2002-2010 (with the exception of 2006), the sampling team documented more fish than were reported as being landed in at least one division (ICES 2011). A documented salmon could be one that was either sampled, checked for an adipose clip only or was not sampled but seen. When this type of discrepancy occurs, the reported landings are adjusted to include the total weight of the fish documented as being landed during the sampling period and the adjusted landings are included in all further assessments. In 2011 this did not occur in any of the sampled communities (Table 1). The reported landings and adjusted landings for 2002-2011 are presented in Table 2. To provide the most reliable estimate of catch and therefore the potential impact on contributing stocks, it is important to continue to improve the catch landings procedure and quality of the catch statistics.
For the Baseline Sampling Program, landed fish were sampled at random and when possible the total catch was examined. Fish were measured (fork length, mm) and weighed (gutted weight or whole weight, kg). Scales were taken for age determination and adipose fins were taken for DNA analysis. Fish were also examined for fin clips, external marks, external tags, and internal tags and adipose clipped fish were sampled for microtags (coded wire tags).
A total of 1,591 salmon were seen by the sampling teams. Of these, 198 fish were only checked for an adipose clip and additional data were collected from 970 as follows:
- 967 fork lengths;
- 964 gutted weights;
- 433 whole weights;
- 965 scale samples;
- 964 genetic samples;
- 431 sex identifications from gonadal examination.
A total of 15 adipose clipped fish were documented. Of all the fish examined by the samplers, three had either an external or internal tag (two of these also had an adipose clip). There were also three additional tags submitted to the Nature Institute by local fisherman from un-sampled fish (two from fish harvested in 2010 and one from a fish harvested in 2011). The tag breakdown was as follows (Table 3):
- 4 Carlin/streamer tags;
- 1 acoustic (VEMCO) tag;
- 1 Passive Integrated Transponder tag.
Sampling for the Baseline Program in Nuuk often took place at the local market as this was a centralized location where harvested salmon were present and available. Prior to any sampling, the sampler would always obtain permission from the market manager. The arrangement was successful for the first Nuuk sampler. However, concerns that proper arrangement had not been made to allow access to the fish prevented the second Nuuk sampler from obtaining any samples from the market. No solution was agreed during the remainder of the sampling season and consequentially the Nuuk sampler was unable to collect any additional Baseline Samples in 2011. This same problem had occurred in Nuuk in previous years, but it has not occurred elsewhere. Both Nuuk samplers were able to collect Baseline and Enhanced Samples from fish purchased directly from the fishermen. The sampling program in 2012 may opt not to sample in Nuuk until this issue can be resolved. This could hinder the program's ability to accurately characterize the harvest as a large proportion of the annual landings are reported from Nuuk.
The limitation of the fishery to internal use only fishing caused practical problems for the sampling teams; however, the sampling program was successful in adequately sampling the Greenland catch, both temporally and spatially. The need to obtain samples from fish landed in Nuuk, especially in the future once the Enhanced Sampling Program is completed, should be considered.
Fin tissue samples were collected and preserved in RNAlater. A total of 964 samples were collect from four communities in four NAFO divisions: Ilulissat in 1A (n=55), Sisimiut in 1B (n=272), Nuuk in 1D (n=386), and Qaqortoq in 1F (n=251). Unfortunately, only 692 samples could be processed before this document was drafted. The Sisimiut (1B) samples (n=272) were accidentally packaged in a box with the formalin preserved Enhanced Samples and were transported back to the US via marine transport. The samples will be processed in 2012 and all sampling data will be updated prior to the 2013 assessment.
DNA isolation and the subsequent microsatellite analyses were performed in the US (King et al. 2001). A database of approximately 5,000 Atlantic salmon genotypes of known origin was used as a baseline to assign these individuals to continent of origin. In total, 91.5% of the salmon sampled were determined to be of North American origin and 8.5% were of European origin. The NAFO Division-specific continent of origin assignments are presented in Table 4.
These data show sustained high proportions of fish from the North American stock complex contributing to the fishery over the past 10 years (Figure 3). The variability in the recent stock complex contributions between Divisions and the deviation from past trends (Figure 4) underscores the need to annually sample multiple NAFO Divisions to achieve accurate estimates of continental contributions to the harvest.
Variations in the estimated weighted proportions of North American and European salmon from 1987-2011 are shown in Table 5 and Figure 4. The 2011 North American weighted contribution (92.0%) to the fishery was one of the highest on record. In addition, the weighted numbers of North American and European Atlantic salmon caught at Greenland (excluding the reported harvest from ICES Area XIV) were calculated for the 2011 fishery. Approximately 6,800 fish from North America and 600 fish from Europe were harvested (Table 5 and Figure 5). The 2011 total is a decrease from 2010 and remains among the lowest in the time series.
Biological characteristics (length, weight, and age) were recorded for all sampled fish. Overall, the mean sampled fork length was 66.4 cm and the mean gutted weight was 3.00 kg across all sea ages.
There was an overall decrease in mean whole weight of both European and North American 1SW salmon from 1969-1995 (Table 6 and Figure 6). This trend was reversed in 1996 when mean weights began to increase. In 2011, the mean length of North American 1SW salmon was 66.2 cm and the mean whole weight was 3.56 kg; the mean length of European 1SW salmon was 65.0 cm and the mean whole weight was 3.24 kg. The North American whole weight estimate increased slightly over the 2010 (3.44 kg) value whereas the European estimate remained the same (3.24 kg). Both estimates are greater than the 10-year North American and European mean whole weight estimates (3.14 and 3.13 kg respectively). The North American and European fork length estimates decreased slightly over the 2010 value (66.7 and 65.2 cm respectively), but increased from the 10-year means (64.7 and 64.6 cm respectively). A breakdown of the mean fork lengths and whole weights by sea age, continent of origin and NAFO Division for the 2011 fishery is presented in Table 7. It should be noted that the weight data have not been adjusted for date of capture and may not represent a true increase in mean weight over the time series as fish sampled later in the fishing season have had additional time to grow compared to fish sampled early in the fishery (ICES 2011).
The smolt age distribution of the total catch by continent of origin is presented in Table 8. The smolt age distributions by origin for all North American and European origin salmon caught (1968-2011) are provided in Table 9.
In 2011, the proportions by smolt age by continent of origin were:
Continent of origin
Percent of continent of origin by smolt age (years)
The mean smolt age of the 2011 North American origin samples was 2.8 years. Age 1 smolts continue to represent a small portion of the catch (1.5%, previous 10 year mean of 1.8%), which is indicative of relatively low contributions of the more southerly North American populations to the fishery. The percentage of smolt age 2 salmon of North American origin (36.1%) is an increase from 2010 value (21.7%) and the previous 10 year mean (25.2%). Age 3 and older smolts account for 62.4% of the harvest.
The mean smolt age of the European salmon in 2011 was 2.1 years. The percent of smolt age 1 (19.0%) is above the 10 year mean of 13.9% and the age 2 smolt percent (51.7%) is below the previous 10 year mean (58.3%). The contribution of age 3 and older smolts (29.3%) is slightly above the previous 10 year mean (27.8%).
As expected, the 1SW age group dominated the collection at 92.9% (Table 10). This value was a decrease from the 2010 (98.0%) value. The decreased proportion of 1SW fish was evident for both North American and European origin fish.
In 2011, the proportions by sea age by continent of origin were:
Continent of origin
Percent of continent of origin by sea age (years)
In addition to the Baseline Sampling Program described above, an Enhanced Sampling Program (SALSEA Greenland) was developed to conduct diverse and more detailed sampling on a fixed number of fish harvested from the waters off West Greenland. The Enhanced Sampling was designed to be integrated within the Baseline Sampling Program's infrastructure. Fresh whole fish were purchased directly from individual fishermen, and these fish underwent the Baseline Sampling Program, plus a more detailed sampling program (Enhanced Sampling). SALSEA Greenland is an integral part of the larger SALSEA research program.
The Enhanced Sampling Program was successfully undertaken in 2011. A total of 430 fresh whole fish were purchased and sampled. All carcasses, post sampling, were donated for consumption to various people within the individual communities where the sampling took place.
This was the third and final year of Enhanced Sampling Program. A total of 1200 samples were collected across 4 NAFO Divisions for this project (Table 11). Sample processing is ongoing and at various stages of completion. Continued close coordination amongst all the researchers involved in the SALSEA Greenland effort is essential to maximize the benefit gained from this research initiative. An inventory of sample types collected, their purpose, and primary Agency/Institutional contacts responsible for their processing is provided in Table 12.
As part of the sampling, sex was determined by examination of the gonads of 431 fish. The percentage by sex was 11.8% males (n=51) and 88.2% females (n=380).
We would like to acknowledge the Greenland Institute of Nature Resources and the fishers and residents in Greenland who provided access to their fish. We would also like to thank the above referenced laboratories and agencies for supporting the program, providing the samplers and the funding necessary to support them in Greenland. Funding support for the samplers was provided by the Department for Environment, Food and Rural Affairs, UK (for Marta Assunção), Fisheries and Oceans Canada, Ottawa (for Denise Deschamps), the Marine Institute (for Ger Rogan), Marine Scotland (for Nick Chisholm) and NOAA Fisheries Service (for Mark Renkawitz and Timothy Sheehan). Fisheries and Oceans Canada (Newfoundland and Labrador Region) conducted the ageing of all scale samples collected and maintains the master sampling database. NOAA Fisheries Service provided funding to the U. S. Geological Survey to support the genetic processing and continent of origin analysis.
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