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Harp Seals - Greenland, 2008
Marine Resource  Fact Sheet
ICES Advice 2009
Harp Seals - Greenland, 2008
Fact Sheet Citation  
Harp Seals - Greenland
Owned byInternational Council for the Exploration of the Sea (ICES) – More
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Species:
FAO Names: en - Harp seal, fr - Phoque du Groenland, es - Foca de Groenlandia, ar - فُقمة غرويلاند, zh - 琴海豹, ru - Тюлень гренландский (=лысун)
Geographic extent of Harp 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 following parameters were used for the assessments of the Greenland Sea harp seals:


Table 3.3.3.3.1. Estimates of proportions of mature females (p) at ages 2–10.
Age 2 3 4 5 6 7 8 9 10
p 0.01 0.02 0.04 0.10 0.24 0.53 0.89 0.99 1.00


Table 3.3.3.3.2. Survey estimates of Greenland Sea harp seal pup production.
Year Estimate c.v.
1983 58 539 0.10
1984 103 250 0.15
1985 111 084 0.20
1987 49 970 0.08
1988 58 697 0.18
1989 110 614 0.08
1990 55 625 0.08
1991 67 271 0.08
2002 98 500 0.18
2007 102 200 0.25



The prior distributions for M1+, M0, and F are given in Table 3.3.3.3.3. The mean of the prior distributions for M0 was taken to be approximately three times that of M1+. The estimated population is presented in Table 3.3.3.3.3, and the population trajectories can be found in Figure 3.3.3.3.2. The estimate of the harp seal 1+ year population abundance in the Greenland Sea is 646400 (CV = 0.16), and pup production was estimated to be 109800 (CV = 0.15) for a total population of 756200 (CV = 0.14).


Table 3.3.3.3.3. Status of harp 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+ 0.09 0.13 0.08 0.19
M0 0.27 0.32 0.24 0.38
F 0.69 0.19 0.833 0.20
N1+(2007) 646400 104080    
N0(2007) 109800 16100 102200 25499


Figure 3.3.3.23.2. Fitted model and model diagnostics for harp 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).


Management
Management unit: Yes

Management Objectives

Catch data

Catches (Table 3.3.3.3.5) have remained significantly less than the quota (Table 3.3.3.3.6) since 1993.

Catch options

The Greenland Sea harp seals are currently regarded as data poor due to old reproductive data, and if hunt is allowed, catch options should be based on the use of the Potential Biological Removals (PBR) approach (ICES, 2006a). The Potential Biological Removals has been defined as:

PBR = 0.5*Rmax*Fr*Nmin,

where Rmax is the maximum rate of increase for the population, Fr is the recovery factor with values between 0.1 and 1, and Nmin = 673050 is the estimated population size using the 20th percentile of the log-normal distribution. Rmax is set at a default of 0.12 for pinnipeds. The recovery factor Fr was set to 1 because the population appears to be high and is at least stable (Wade and Angliss, 1997). The PBR level is estimated to be 40383 (Table 3.3.3.3.4). This assumes that the age structure of the removals is proportional to the age composition of the population. It is estimated that the current composition of the population includes 14% pups. A catch consisting of a higher proportion of pups would be more conservative, but a multiplier to convert age 1+ animals to pups is inappropriate.

Impacts of three different catch scenarios as requested by the Norwegian Ministry of Fisheries and Coastal Affairs were considered:

  1. Current harvest levels,
  2. Sustainable catches (defined as the fixed annual catches that stabilizes the future 1+ population),
  3. Twice the sustainable catches.


Because of the data-poor status of the stock, WGHARP assumed the PBR level to be equivalent to the sustainable catch. The recent average annual catch (2003–2007) was used as a proxy for the current harvest level catch option.

Current catch levels will likely result in an increase in population size of 43% over the next 10 years, whereas catches at PBR will result in a decline over the next 10 years of 7%, and 2 × PBR levels will result in the population declining by approximately 63%.


Table 3.3.3.3.4. Catch options with relative population size (D1+) in 10 years (2017) for harp seals in the Greenland Sea.
Option #Catch levelProportion of pups in catchesTotal catchD1+Option #Catch level
    Lower CIPoint est.Upper CI
1Recent average (2003–2007)74.5% 5 8221.191.431.67
2PBR 14.0%40 3830.600.931.25
32 × PBR 14.0%80 7660.000.370.80


Table 3.3.3.3.5. Catches of harp seals in the Greenland Sea (“West Ice”) from 1946 through 2008a. Totals include catches for scientific purposes.
YearNorwegian catchesRussian catchesTotal catches
 Pups1 year and olderTotalPups1 year and olderTotalPups1 year and olderTotal
1946–5026606946436070---26606946436070
1951–5530465912539590---b30465912539590
1956–6018887617125058114812172365b20035738827423
1961–651547731431862027521898465018229504123270
1966–70168171641184581474816818168818506
197111149011149---11149011149
1972151008215182---151008215182
197311858011858---11858011858
1974146287414702---146287414702
19753742108048222390239398110805061
19767019524912268253342877272528312555
1977133051541148462000252225215305179317098
1978144245714481200002000164245716481
197911947889128362424024241437188915260
1980233676479983300053935395336818613522
1981893228501178236930369312625285015475
1982660230909692196124322048563333311896
198374225763318426304263500525767581
198419917791978---19917791978
19855322555736953531566
1986156214490250474045052564761
19877961348311444-330033007961678314744
1988449351709663c7000500750011493567017163
19893743924429---3743924429
1990265482550807847842662666292
19910486748675001328182850061956695
19920775077505901293188359090439633
1993035203520---035203520
199408121812107272081938193
199531778898206---31778898206
199656497786427---56497786427
199719621992161---19621992161
199817071771884---17071771884
1999608195803---608195803
20006328601512343---6328601512343
200122677252992---22677252992
200211181141232---11181141232
200316121162277   16121162277
2004828816079895   828816079895
2005468025257205   468025257205
200623439613304   23439613304
2007618816407828   618816407828
20087445191263   7445191263

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 were reported at 3900, 11600, and 12900, respectively (Sov. Rep. 1975). These catches are not included.

c Including 1431 pups and one adult caught by a ship which was lost.



Table 3.3.3.3.6. Summaries of Norwegian harp and hooded sealing regulations1 for the Greenland Sea (“West Ice”), 1985–2008.
YearOpening DateClosing DateQuotasAllocations
   TotalPupsFemaleMaleNorwaySoviet & Russian
Hooded Seals 
198522 March5 May(20,000)2(20,000)203Unlim.8,00043,300
198618 March5 May9,3009,30003Unlim.6,0003,300
198718 March5 May20,00020,00003Unlim.16,7003,300
198818 March5 May(20,000)2(20,000)203Unlim.16,7005,000
198918 March5 May30,000003Incl.23,1006,900
199026 March30 June27,50000Incl.19,5008,000
199126 March30 June9,00000Incl.1,0008,000
1992–9426 March30 June9,00000Incl.1,7007,300
199526 March10 July9,00000Incl.1,70077,300
199622 March10 July9,0008   1,7007,300
199726 March10 July9,0009   6,2002,80011
199822 March10 July5,00010   2,2002,80011
1999–0022 March10 July11,20012   8,4002,80011
2001–0322 March10 July10,30012   10,300 
2004–0522 March10 July5,60012   5,600 
200622 March10 July4,000   4,000 
2007–0814  000000
Harp Seals       
198510 April5 May(25,000)2(25,000)205057,0004,500
198622 March5 May11,50011,50005057,0004,500
198718 March5 May25,00025,000050520,5004,500
198810 April5 May28,00005,605,605,621,0007,000
198918 March5 May16,000-050512,0009,000
199010 April20 May7,200005055,4001,800
199110 April31 May7,200005055,4001,800
1992–9310 April31 May10,900005058,4002,500
199410 April31 May13,1000050510,6002,500
199510 April31 May13,1000050510,60072,500
199610 April31 May813,1009   10,6002,50011
1997–9810 April31 May13,10010   10,6002,50011
1999–0010 April31 May17,50013   15,0002,50011
2001–0510 April31 May15,00013    15,0000
2006–0710 April31 May31,200   31,2000
20085 April31 May31,200   31,2000

1 Other regulations include: Prescriptions for date for departure Norwegian port; only one trip per season; licensing; killing methods; and inspection.

2 Basis for allocation of USSR quota.

3 Breeding females protected ; two pups deducted from quota for each female taken for safety reasons.

4 Adult males only.

5 1 year+ seals protected until 9 April; pup quota may be filled by 1 year+ after 10 April.

6 Any age or sex group.

7 Included 750 weaned pups under permit for scientific purposes.

8 Pups allowed to be taken from 26 March to 5 May.

9 Half the quota could be taken as weaned pups, where two pups equalled one 1+ animal.

10 The whole quota could be taken as weaned pups, where two pups equalled one 1+ animal.

11 Russian allocation reverted to Norway.

12 Quota given in 1+ animals, parts of or the whole quota could be taken as weaned pups, where 1,5 pups equalled one 1+ animal.

13 Quota given in 1+ animals, parts of or the whole quota could be taken as weaned pups, where 2 pups equalled one 1+ animal.

14 Hooded seals protected, only small takes for scientific purposes allowed.



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

The adult population is at the highest level estimated in the historical time-series. Based on previous (1983–1991) mark–recapture data and recent (2002, 2007) aerial survey data, the stock in 2007 is estimated to be 756200 (CV=0.14) seals.

The recent average annual catch (2003–2007) has been 5822. The 2008 catches were 1263 animals (including 744 pups) or 4% of the allocated quota of 31200 seals. The quota has been implemented such that parts of, or the whole quota, could be taken as weaned pups assuming 2 pups equaled one 1+ animal. Russia has not participated in this hunt since 1994.
Source of information
 
ICES.2009.Report of the ICES Advisory Committee, 2009. ICES Advice, 2009.
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