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Hooded Seals - Greenland, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Hooded Seals - Greenland, 2008
Fact Sheet Citation  
Hooded Seals - Greenland
Owned byInternational Council for the Exploration of the Sea (ICES) – More
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Species:
FAO Names: en - Hooded seal, fr - Phoque à crete, es - Foca capuchina, ar - فُقمة ذات قُنْزعة, zh - 冠海豹, ru - Хохлач
Geographic extent of Hooded Seals - Greenland
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Sub-Regional
Management unit: Yes
 
 
Habitat and Biology
Vertical distribution: Pelagic.  

Geographical Distribution
Jurisdictional distribution: Shared between nations

Water Area Overview
Spatial Scale: Sub-Regional

Geo References
Resource Structure
Considered a single stock: Yes
Assessment
 
Overall Assessment Results

Population estimates

The parameters used for the assessments of the Greenland Sea hooded seals were.


Table 3.3.3.3.10. Estimates of proportions of mature females (p) at ages 2–11.
Age 2 3 4 5 6 7 8 9 10 11
p 0.05 0.27 0.54 0.75 0.87 0.93 0.97 0.98 0.99 1.00


Table 3.3.3.3.11. Survey estimates of Greenland Sea hooded seal pup production.
Year Estimate c.v.
1997 24 000 0.28
2005 15 200 0.25
2007 15 370 0.11



The prior distributions for M1+, M0, and F (Table 3.3.3.3.12) are as in ICES (2006b). The mean of the prior for M0 was taken to be approximately three times that of M1+. The model runs shown in Figure 3.3.3.3.3 seem to indicate a substantial decrease in population abundance from the late 1940s and up to the early 1980s. In the most recent two decades, the population size appears to have been relatively stable at a low level, but the current trajectory is uncertain. Using a prior value of M1+ of 0.11 (CV = 0.45), a 2007 abundance of 66890 (CV = 0.13) is obtained for age 1+ seals while the estimated number of pups is 15490 (CV = 0.10), combining to a total of 82380 animals (CV = 0.11).


Table 3.3.3.3.12. Status of hooded seals in the Greenland Sea in 2007. The column “Model Estimate” shows the estimated parameters (point estimate and standard deviations), while the column “Prior” shows the prior distributions placed on parameters.
Parameter Model Estimate Prior
  Est. C.V Mean C.V
M1+ 0.157 0.22 0.11 0.46
M0 0.334 0.15 0.33 0.15
F 0.869 0.11 0.88 0.11
N1+(2007) 66 890 8 645    
N0(2007) 15 490 1 528 15 370 1 675


Management
Management unit: Yes

Management Objectives

Catch data

Between 1990 and 2006 less than 30% of the quota was taken each year. Catches in 2007–2008 were zero. Catches (Table 3.3.3.3.10) have remained significantly less than the quota since 1993 (Table 3.3.3.3.7).

Catch options

The Greenland Sea hooded seal population in 2007, as shown in Figure 3.3.3.3.3, was well below Nlim (30% of Nmax ~ 789000 animals). As such, WGHARP recommends that no harvest be allowed for Greenland Sea hooded seals at this time because the stock size is below Nlim. This follows the Precautionary harvest strategy developed by WGHARP (ICES, 2006a, 2006b). Furthermore, the fit of the population model for Greenland Sea hooded seals was too poor to allow the impact of harvest options to be evaluated with a reasonable degree of confidence.


Figure 3.3.3.3.3. Fitted model and model diagnostics for hooded seals in the Greenland Sea. Estimated N1+ population trajectory (panel labelled Adult). The lower panel shows 95% intervals (vertical bars) for available pup production estimates, and modelled pup production (solid line).


Table 3.3.3.3.13. Catches of hooded seals in the Greenland Sea (“West Ice”) from 1946 through 2008a. Totals include catches for scientific purposes.
Year Norwegian catches Russian catches Total catches
  Pups 1 year and older Total Pups 1 year and older total Pups 1 year and older Total
1946–50 31152 10257 41409 - - - 31152 10257 41409
1951–55 37207 17222 54429 - - -b 37207 17222 54429
1956–60 26738 9601 36339 825 1063 1888b 27563 10664 38227
1961–65 27793 14074 41867 2143 2794 4937 29936 16868 46804
1966–70 21495 9769 31264 160 62 222 21655 9831 31486
1971 19572 10678 30250 - - - 19572 10678 30250
1972 16052 4164 20216 - - - 16052 4164 20216
1973 22455 3994 26449 - - - 22455 3994 26449
1974 16595 9800 26395 - - - 16595 9800 26395
1975 18273 7683 25956 632 607 1239 18905 8290 27195
1976 4632 2271 6903 199 194 393 4831 2465 7296
1977 11626 3744 15370 2572 891 3463 14198 4635 18833
1978 13899 2144 16043 2457 536 2993 16356 2680 19036
1979 16147 4115 20262 2064 1219 3283 18211 5334 23545
1980 8375 1393 9768 1066 399 1465 9441 1792 11233
1981 10569 1169 11738 167 169 336 10736 1338 12074
1982 11069 2382 13451 1524 862 2386 12593 3244 15837
1983 0 86 86 419 107 526 419 193 612
1984 99 483 582 - - - 99 483 582
1985 254 84 338 1632 149 1781 1886 233 2119
1986 2738 161 2899 1072 799 1871 3810 960 4770
1987 6221 1573 7794 2890 953 3843 9111 2526 11637
1988 4873 1276 6149c 2162 876 3038 7035 2152 9187
1989 34 147 181 - - - 34 147 181
1990 26 397 423 0 813 813 26 1210 1236
1991 0 352 352 458 1732 2190 458 2084 2542
1992 0 755 755 500 7538 8038 500 8293 8793
1993 0 384 384 - - - 0 384 384
1994 0 492 492 23 4229 4252 23 4721 4744
1995 368 565 933 - - - 368 565 933
1996 575 236 811 - - - 575 236 811
1997 2765 169 2934 - - - 2765 169 2934
1998 5597 754 6351 - - - 5597 754 6351
1999 3525 921 4446 - - - 3525 921 4446
2000 1346 590 1936 - - - 1346 590 1936
2001 3129 691 3820 - - - 3129 691 3820
2002 6456 735 7191 - - - 6456 735 7191
2003 5206 89 5295 - - - 5206 89 5295
2004 4217 664 4881 - - - 4217 664 4881
2005 3633 193 3826 - - - 3633 193 3826
2006 3079 568 3647       3079 568 3647
2007 27 35 62       27 35 62
2008 9 35 44       9 35 44

a For the period 1946–1970 only 5-year averages are given.

b For 1955, 1956, and 1957 Soviet catches of harp and hooded seals reported at 3900, 11600, and 12900, respectively. These catches are not included.

c Including 1048 pups and 435 adults caught by one ship which was lost.



Biological State and Trend
Exploitation rate: Undefined
Abundance level: Undefined

The adult population is at the lowest level estimated in the historical time-series. Model-based estimates for the population suggest that the stock in 2007 included 82380 seals.

Results from the 2007 pup survey suggest that current pup production (15370 pups, CV = 0.11) remains low and is significantly lower than observed in the 1997 survey (24 000 pups, CV = 0.28). Model explorations indicate a substantial decrease in population abundance from the late 1940s and up to the early 1980s. In the most recent two decades, the stock appears to have stabilized at a low level, but the current trajectory remains uncertain.

The stock is estimated to be well below Nlim. WGHARP had previously recommended (ICES, 2006b) no catches of Greenland Sea hooded seals, and as a result, there was no catch in 2007–2008.
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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