Report of the working group on seals

Appendix 8

The 29th session of the joint Norwegian - Russian Fisheries Comission, Russia 13 - 17 November 2000

Report of the working group on seals

Participants:

RUSSIA

V. A. POTELOV SevPINRO, Archangelsk

G. ANTROPOV Rosribkolhozsojus, Moscow

O. PODKORYTOVA Goskomrybolostvo, Moscow

NORWAY

T. HAUG Norwegian Institute of Fisheries and Aquaculture,

Tromsø

W. KIIL Trade Union for Fishermen, Tromsø

K. HENRIKSEN Norwegian Ministry of Fisheries, Oslo

C. MORDAL Norwegian Embassy, Moscow

E. FREMMING Norway (interpreter)

Contents:

1 Exchange of information and summary of seal catches in 2000.

2. Exchange of information and summary reports of research activities in 2000.

3. The status of stocks and management advice for 2001.

4. Research program for 2001.

5. Other business.

1. EXCHANGE OF INFORMATION AND SUMMARY OF SEAL CATCHES IN 2000

Norwegian catches were taken by two vessels in the Greenland Sea and one vessel in the southeastern Barents Sea. For logistical reasons, Russian seal vessels did not carry out hunting in the Greenland Sea in 2000. Russian catches of harp seals in the White Sea were taken by local hunters.

The recommended 2000 TACs for Greenland Sea hooded seals was 11,200 one year old and older (1yr+) animals or 18,000 pups - if a harvest scenario including both 1yr+ animals and pups were chosen, one 1yr+ animal should be balanced by 1.5 pups. For the Greenland Sea harp seals, the 2000 TAC was recommended at 17,500 1yr+ animals or 36,700 pups - if a harvest scenario including both 1yr+ animals and pups were chosen, one 1yr+ animal should be balanced by 2 pups. The 2000 Greenland Sea quotas followed the recommendations given by the ICES Advisory Committee on Fisheries Management (ACFM) - quotas allocated to Russia in this area was 2,800 and 2,500 1yr+ animals of harp and hooded seals, respectively. The 2000 TAC recommended for harp seals in the Barents Sea and White Sea was defined at 31,600 1yr+ animals or 76,000 pups by ACFM - if a harvest scenario including both 1yr+ animals and pups were chosen, one 1yr+ animal should be balanced by 2.5 pups. However, as a result of the discussions in the Working Group on Seals in 1998 and subsequently in the in the 27 ^th> and 28th sessions of the Joint Norwegian-Russian Fisheries Commission (in 1998 and 1999, respectively), the qouta set by Russia for harp seals in 2000 in the this area was reduced to 27,700 1yr+ animals, where of Norway was allocated 5,000. The balance between pups and 1yr+ animals was maintained at 2.5 pups per one 1yr+ animal.

Norwegian and Russian catches in 2000, including catches under permits for scientific purposes, are summarized in the table below: ______________________________________________________________

Area/species Norway Russia Sum

__________________________________________________________________________

GREENLAND SEA

Harp seals

Pups 6328 0 6328

Older seals (1yr+) 6015 ¹> 0 6015

Sum 12343 0 12343

Hooded seals

Pups 1346 0 1346

Older seals (1yr+) 590 ²> 0 590

Sum 1936 0 1936

Area subtotal 14279 0 14279

BARENTS SEA / WHITE SEA

Harp seals

Pups 2253 38302 40555

Olderseals (1yr+) 4104 111 4215

Sum 6357 38413 44770

Area subtotal 6357 38413 44770

TOTAL CATCHES 20636 38413 59049

_______________________________________________________________________

¹> Including 22 1yr+ animals taken under permit for scientific purposes

²> Including 65 1yr+ animals taken under permit for scientific purposes

Incidental catches (gillnets etc.) of harp seals at the Norwegian coast (mainly Finnmark) were 439 animals in 2000.

2. EXCHANGE OF INFORMATION AND SUMMARY REPORTS OF RESEARCH ACTIVITIES IN 2000

2.1 Norwegian research

Biological material was collected from harp seals taken during the commercial hunting operations in March-May in the East Ice. This includes collections of samples for age determination from moulting harp seals, and data for studies of development in body condition of pups in the first period after weaning. Additionally, material for studies of seasonal variations in adult body condition was collected. From collected data it appears that the 1986-1988 year classes, possibly also the 1993-1995 year classes, are very poorly represented in the East Ice harp seal population. To better understand the apparent variations in annual recruitment to the seal populations, The Working Group recommend that collection of biological material from pups and older seals taken in commercial catches continues.

Collection of biological data from harp seals taken as bycatch in March-April in gill-net fisheries in Finnmark, North Norway, were continued in 2000.

A Norwegian study, initiated to look at possible changes in age at sexual maturity for female harp seals in the Greenland Sea from the 1960s until present, is in progress. In 2000, sampling of harp and hooded seal pups and 1yr+ animals taken in commercial catches was performed on one of the Greenland Sea vessels. This included data for studies of demographic patterns in adult seals, and of body condition in pups and adults. As for the East Ice, the Working Group recommend that collection of biological material from pups and older seals taken in commercial catches continues also in the West Ice. Some animals were taken for scientific purposes (studies of various aspects of physiology) during a dedicated research survey in March.

A satellite tag experiment was initiated in June in 1999 when satellite tags were deployed on 11 moulted harp seals in the Scoresby Sound area on the east coast of Greenland. The results from this experiments are now being analysed, and are due to be published early in 2001.

A project aimed to provide the data necessary for an assessment of the ecological role of Greenland Sea harp and hooded seals throughout their distributional area of the Nordic Seas (Iceland, Norwegian, Greenland Seas) was initiated with a pilot study where seals were collected for scientific purposes on an expedition with R/V"Jan Mayen", conducted in the pack ice belt between Svalbard and Greenland during 23 September to 11 October 1999. The observed diets of the seals were comprised of relatively few prey taxa. Pelagic amphipods of the genus Parathemisto (most probably almost exclusively P. libellula), the squid Gonatus fabricii and the polar cod Boreogadus saida were particularly important in that they constituted 85-98% of the diet in hooded seals and 95% in harp seals in terms of calculated biomass. In addition to the diet studies, biological material for studies of nutritional status, lipid contents, age, reproduction, genetics and pollutants were collected from the seals.

The project will continue in 2000-2002, preferably (i.e., if sufficient funding is obtained) as a joint effort for the four NAMMCO-countries Greenland, Iceland, Faroes and Norway. In 2000, a research cruise with R/V"Jan Mayen" along the ice edge and in the pack ice east of Greenland between approximately N70° 30’ and N77° 30’ was performed in the period 19 July - 2 August. Biological material for studies of feeding habits, nutritional status, lipid contents, age, reproduction, genetics and pollutants were collected from 22 harp and 65 hooded seals. Simultaneously with the sampling on dedicated cruises, it is intended that harp and hooded seals taken by local hunters in eastern Greenland and as bycatches in other fisheries in Iceland and the Faroes, shall be sampled for the same parameters in these countries.

2.2 Russian research

During the 1997 and 1998 meetings of The Joint ICES/NAFO Working Group on Harp and Hooded seals (WGHARP), it was noticed and appreciated that Russian scientists had made substantial efforts to obtain reliable pup production estimates for the White and Barents Sea stock of harp seals. As also stated in the 1998 report, WGHARP looked forward to see progress in this Russian work, including experimentation with the isohaline method as well as further analyses of the 1998 photographic survey data. In January 2000 Russian scientists decided that new aerial pup surveys would be conducted in the White Sea during the 2000 breeding season.

Two fully independent surveys of the breeding lairs were conducted: one with helicopter and one with aeroplane. The helicopter, plane and photographic equipment applied were virtually identical to what were used in the 1997 and 1998 surveys. The base for the helicopter surveys was a small village named Zimnyaja Zolititsa north of Arkhangelsk.The helicopter photographic (black and white) survey was performed, starting in the north and proceeding south and southwestwards during the period 10-12 March, usually with two flights per day. The whole breeding area was covered with parallell transects between which the distances were 7.4 km in lowdensity areas or 3.7 km in more densely populated areas. Using the strip transect method, a mean uncorrected estimate of pups of 322,474 (SE=28,706), including pups harvested prior to the survey (30,729 pups), was obtained. This estimate was accepted by WGHARP. A somewhat higher estimate was obtained when the data were analysed using the isoline method, which gave a mean uncorrected estimate of pups (including catch) of 346,200 (SE=8,653). None of the estimates were corrected for pups born after the survey. The isoline method, based on kriging in this example, is highly sensitive to the options used. The Working Group recommend that the method is further investigated, and that the options used for the estimate be clearly described when the results are presented.

The aeroplane was stationed in Arkhangelsk. Using information about positions of the breeding lairs obtained during the helicopter surveys, the aeroplane aerial surveys started on 13 March with a reconnaissance flight. The first photographic survey was performed on 16 March (with Norwegian participation) during which about half of the breeding lair was covered with parallell transects with a distance of 7.5 km between them. On 18 March a full coverage survey was successfully performed with the aeroplane. Like similar surveys conducted in 1997-1998, the survey was conducted by traditional strip transect methods using multiple sensors. As in the previous surveys these included black and white photography, but thermal infrared (IR) scanning and video cameras (25º and 6º vision angles) replaced IR-photo cameras. All devices were operated simultaneously during the survey. However, only preliminary results from a combination of video (25º) and IR, which covered a strip width of 78.2 meters, and IR-camera, which covered 224.8 meters, were presented. The IR and video (6º) were compared to correct for pups not visible to the video (25º) camera. An uncorrected pup production estimate of 339,710 (SE=32,400), which includes pups harvested prior to the survey (30,729 pups), was obtained. This estimate was also accepted by WGHARP.

The Working Group commended the high quality of the Russian research in both the aeroplane and helicopter surveys and encouraged them to continue the analyses, in particular to develop relevant correction factors to the pup production estimates, and to publish the final results in an international scientific journal. The estimates from both year 2000 surveys confirm the 1998 estimate, and give strong evidence of a harp seal pup production of at least 300,000 in the White Sea.

Studies of White Sea harp seal breeding period were carried out from February 28 to March 9. In total 1056 pups were checked for sexual ratio, which was close to 1:1. On February 28, nearly 21% of the investigated pups were 1-2 days old (n=69). Up to March 3 the fraction of this age group was reduced to 6.4% (n=234), while on March 9 this parameter had grown to 7.8 % (n=51). Average pup body weight on February 28 was 13.3± 0.36 kg (n=69). On March 3 body weight had increased to 16.3 ± 0.26 kg (n=234), and on March 9 it had reached 24.6± 1.27 kg (n=51). Apparantly, harp seal breeding was a little earlier in 2000 than in 1999.

To study age structure, feeding, breeding and morphology, 109 adult females were caught on the breeding grounds. The average age of the females was 17.4 ± 0.46 years (n=108). The fraction of animals aged 20 years and older was 26.85 %. Average female weight during March 4 - 8 was 118.1 ± 2.47 kg (n=50), average zoological length was 180.6 ± 1.10 sm (n=50) and standard lenght was 169.4 ± 1.15 sm (n=50). Average thickness of dorsal blubber was 58.1 ± 1.5 mm (n=50), and of pectoral blubber 43.2 ± 1.1 mm (n=50).

2.3. Joint Norwegian-Russian work

Using data collected by Russian scientists in the Greenland Sea in previous years, life history parameters (growth, age at maturity, fecundity, ovulation time) of harp seal females are being studied in a joint Norwegian-Russian project. Preliminary results from these analyses will be presented at the meeting in WGHARP in October 2000, and the data were used in the stock assessments.

On several occasions WGHARP has discussed the possibilities and undisputable advantages involved in exchange of scientists between the "harp-and-hooded-seal-counting" countries during each others field work and subsequent analyses, discussions and presentations of results. This would ensure standardisation of both the field- and analytical methods involved. During the 1999 meeting of the Joint Norwegian-Russian Fisheries Commission in Murmansk, Russian scientists had, in fact, encouraged Norwegian scientists to patrticipate in their planned 2000 aerial surveys in the White Sea. Upon request to Russian scientists about a possible Norwegian and Canadian participation in these surveys, field work as well as subsequent analyses, an immediate positive answer and invitation was received. Norway participated with four persons during field work in the period 6 – 17 March 2000.

Russian scientists have previously requested Norwegian scientists about joint participation in research onboard Norwegian sealers. In 2000, Vitaly Prischemikhin from SevPINRO, Arkhangelsk, collected biological material from seals taken on one of the Norwegian sealers operating in the Greenland Sea.

Analysis of 1995-1997 data collected from satellite tags deployed on harp seals in the White Sea as part of a joint Norway-Russian research program, continues and is assumed to result in a joint publication early in 2001. The Working Group recommends to continue experiments with satellite tags on harp seals in the White Sea.

3. STATUS OF STOCKS AND MANAGEMENT ADVICE FOR 2001

WGHARP met in the ICES headquarters, Copenhagen, Denmark, 2-6 October 2000 to assess the stocks of Greenland Sea harp seals, White Sea / Barents Sea harp seals and Greenland Sea hooded seals. Also, possible use of biological reference points in the management of seal stocks was discussed. New information about pup production was available, and enabled WGHARP to perfrom modelling which provided ACFM with sufficient information to give advice on both status and catch potential for all the three mentioned seal stocks.

Management agencies have requested advice on "sustainable" yields for these stocks. ACFM notes that the use of "sustainable" in this context is not identical to its interpretation of "sustainable" applied in advice on fish and invertebrate stocks. "Sustainable catch" as used in the yield estimates for seals means the catch that is risk neutral with regard to maintaining the population at its current size. As illustrated by the lower confidence interval obtained in the analyses, when "sustainable" catches are removed annually, the stock in 10 years may be lower by sometimes as much as 50%, compared to size of the stock at present. The stock may also be as much as 50% larger. The crucial point is even at the lower confidence bound the population is so large that its future viability has not been impacted.

The population assessments were based on a population dynamics model that estimates the development of future population size, for which statistical uncertainty is provided for each set of catch options. The age structure of the model was restricted to two age classes, 0 (pups) and 1+(one year old or older), because of limited information on catch at age and age structure for the populations in question, and because of the fact that catches were rather small compared to population size for the years for which catch at age is known. The model requires estimates of mortality and reproductive parameters that include variance. Using the historical catch data and estimates of pup production, the model estimates mortality (M ₀ and M ₁₊) and a birth rate within the 1+ population of females (f). The freedom with which the model can estimate these parameters is dependent upon the standard deviations provided. The model is fitted to pup production estimates weighted inversely to their variance in cases where more than one estimate are available.

The possibility of including multiple pup production estimates in the assessment model is an improvement from previously used estimation programs. However, models of this nature do not estimate parameters well when pup production estimates are from a limited period in time compared to generation time. The model has the option to allow estimation of population size and sustainable catch, but when given no prior information about M ₁₊ and f, the model treats these parameters as independent parameters. To stabilize the model, the range of these parameters had to be constrained. As a result, the estimates of uncertainty may be negatively biased, and the confidence intervals for future population sizes may be too narrow.

The advice given by ACFM in 2000 was used by this Working Group on Seals to establish management advice for 2001 to the Joint Norwegian-Russian Fisheries Commission.

3.1. Greenland Sea

The Working Group recommends the following opening dates for the 2001 catch season: 1) Sucling pups, opening date of 18 March (0700 GMT) for catches of pups of both harp and hooded seals; 2) weaned pups, opening dates 22 March for hooded seals and 10 April for harp seals; 3) seals aged 1 yr and older (1yr+), opening date 22 March for hooded seals and 10 April for harp seals. Adult hooded seal males should be permitted taken from 18 March .The Group recommends a closing date set at 30 June (2400 GMT) for harp seals and 10 July (2400 GMT) for hooded seals in 2001. Exceptions on opening and closing terms may be made in case of unfavourable weather or ice conditions. If, for any reason, catches of pups are not permitted, quotas can be filled by hunting moulting seals.

The Working Group agreed that the ban on killing adult females in the breeding lairs should be maintained for both harp and hooded seals in 2001.

3.1.1 Hooded seals

The Working Group noted the conclusion from ACFM that the stock is within safe biological limits, and that recent removals have been well below the recommended sustainable yields. Between 1990 and 2000 less than 30% of the quota was taken each year.

The new populaton model solves for a constant exploitation that stabilise the 1+ population. Inputs to the model were:

Pup production estimate: Results from a Norwegian aerial survey in 1997 which resulted in estimates of pup production in the Greenland Sea of 23 762 pups (95% C.I. 14 819 to 32 705). This estimate is considered to be negatively biased since it was not corrected for the temporal distribution of births or for scattered pups. The actual number of pups produced in 1997 could, therefore, be larger.

Natural mortality: M ₁₊ = 0.1, sd.=0.015 (the M ₁₊ value is similar to what has been used in recent assessments of the stock while the standard deviation is based on the assumption that M ₁₊ should be bounded by the assumed interval 0.07 - 0.13).

Pup mortality: M ₀ = 3M ₁₊ (fixed ).

Age specific pregnancy rates: asp(3)=0.028, asp(4) = 0.262, asp(5) = 0.504, asp(6) = 0.734, asp(7)=0.802, asp(8)=0.802, asp(9)=0.850, asp(10)= 0.908, asp(11)=0.97 (fixed).

Based on this input, the model estimated the following 2000 abundance for Greenland Sea hooded seals:

ACFM gave catch options for two different scenarios: current catch level (average of the catches in the period 1996 – 2000) and sustainable yield. The sustainable catches are defined as the (fixed) annual catches that stabilise the future 1+ population. The catch options are further expanded using different proportions of pups and 1+ animals in the catches.

As a measure of the future development of the estimated population, a quantity that relates future (2010) with current (2000) 1+ population, is used:

.

ACFM emphasize that a catch of 10,300 1+ animals (catch option 4), or an equivalent number of pups, in 2001 would be sustainable. The Working Group recommend that the advise given by ACFM be used as a basis for the determination of a TAC for hooded seals in the Greenland Sea in 2001:

10,300 1+ animals or an equivalent number of pups. If a harvest scenario including both 1+ animals and pups is chosen, one 1+ seal should be balanced by 1.5 pups.

3.1.2 Harp seals

The Working Group noted the conclusion by ACFM that the stock is within safe biological limits, and that recent removals have been well below the recommended sustainable yields.

The new model solves for a constant exploitation which stabilise the 1+ population. Inputs to the model were:

Pup production estimates (from previous tag-recapure experiments):

Natural mortality: M ₁₊ = 0.11, sd.=0.03 (a standard deviation of .03 means that one effectively considers values of M ₁₊ in the range from 0.05 to 0.17).

Pup mortality: M ₀ = 3M ₁₊, sd.=1.

Age at maturity ogive: p(3) = 0.058, p(4) = 0.292 p(5) = 0.554, p(6)=0.744, p(7)=0.861, p(8)=0.926, p(9)= 0.961, p(10)=0.980, p(11)=0.990, p(12)=0.995, p(13)=0.997, p(14)=0.999, p(15)=0.999

Pregnancy rate for mature females: F=0.833, sd.=0.02.

Based on this input, the model estimated the following 2000 abundance for Greenland Sea harp seals:

ACFM gave catch options for two different catch scenarios: current catch level (average of the catches in the period 1996 – 2000) and sustainable yield. The sustainable catches are defined as the (fixed) annual catches that stabilise the future 1+ population. The catch options are further expanded using different proportions of pups and 1+ animals in the catches.

As a measure of the future development of the estimated population, a quantity that relates future (2010) with current (2000) 1+ population, is used:

.

ACFM emphasize that a catch of 15,000 1+ animals (catch option 6), or an equivalent number of pups, in 2001 would be sustainable. The Working Group recommend that the advise given by ACFM be used as a basis for the determination of a TAC for harp seals in the Greenland Sea in 2000:

15,000 1+ animals or an equivalent number of pups. If a harvest scenario including both 1+ animals and pups is chosen, one 1+ seal should be balanced by 2 pups.

3.2 The Barents Sea / White Sea

The Working Group recommends the following terms concerning opening and closing dates and areas of the catches: From 27 February to 20 April for Russian coastal catches and from 23 March to 20 April for Norwegian sealing ships. However, it is proposed that, in the case of difficult weather or ice conditions, the harvesting can be prolonged till 10 may. Exceptions from opening and closing dates should be made, if necessary, for scientific purposes. The Norwegian participants in the Working Group suggest to prolong dates of harvesting to 1 July, and to determine the following operational areas for the catch activities: the White Sea and the southeastern Barents Sea to the east of 20° E .

3.2.1. Harp seal.

The Working Group noted the conclusion of ACFM that the stock is within safe biological limits, that numbers are estimated to be increasing, that catches through the 1990s have been below quotas, and that there is some evidence that densities may be so high that biological processes like rate of maturation may be showing density dependent effects.

The new population model solves for a constant exploitation that stabilise the 1+ population. Inputs to the model were:

Pup production estimate: Russian airplane and helicopter surveys of White Sea harp seal pups were conducted in March 1998 and 2000 using traditional strip transect methodology and multiple sensors. Black and white, ultraviolet and thermal infra-red scanners were operated during the surveys. The estimates are considered to be negatively biased since they were not corrected for pups which may be hidden from the camera or for pups missed by the readers. Furthermore, the survey estimates were not corrected for the temporal distributions of birth. Therefore, actual pup production may be higher than the estimates presented below:

Natural mortality: M ₁₊ = 0.1, sd.=0.015 (the M ₁₊ -value is similar to what has been used in recent assessments of the stock while the standard deviation is based on the assumption that M ₁₊ should be bounded by the assumed interval 0.07 - 0.13)

Pup mortality: M ₀ = 3M ₁₊ (fixed) and M ₀ = 5M ₁₊ (fixed)

Age at maturity ogive: p(5) = 0.1, p(6) = 0.18, p(7) = 0.35, p(8)=0.6, p(9)=0.7, p(10)=0.94, p(11)= 1.0

Pregnancy rate: F=0.84, no standard deviation.

There are reports that pup mortality rates may vary substantially in the White Sea region, and that in recent years these rates have been very high. For this reason, the 2000 abundance of White Sea / Barents Sea harp seals were estimated under two different assumptions about the ratio M ₀/ M ₁₊:

ACFM gavecatch options for two different catch scenarios: current catch level (average of the catches in the period 1996 – 2000) and sustainable yield. The sustainable catches are defined as the (fixed) annual catches that stabilise the future 1+ population. These are calculated under the assumptions that the ratio M ₀/ M ₁₊ is either 3 or 5. The catch options are further expanded using different proportions of pups and 1+ animals in the catches.

As a measure of the future development of the estimated population, a quantity that relates future (2010) with current (2000) 1+ population, is used:

.

Given recent reports of possible high pup mortality rates, ACFM recommend that managers consider the higher pup mortality options (catch options 5 and 6 ) when setting catch quotas, and conclude that a catch of 53 000 1+ animals, or an equivalent number of pups in 2001, would be sustainable. In general, the Working Group recommend that the advise given by ACFM be used as a basis for the determination of a TAC for harp seals in the Barents Sea / White Sea in 2001:

53,000 1+ animals or an equivalent number of pups. If a harvest scenario including both 1+ animals and pups is chosen, one 1+ seal should be balanced by 2.5 pups.

However, Working Group representatives from the Russian party expressed concerns with this increase in TAC from the 2000 level of 31,600 1+ animals, and suggested a more stepwise approach. One Norwegian Working Group representative (Kiil, from the Trade Union for Fishermen) on the other hand expressed concerns over the growing harp seal stock and suggested that the TAC for 2001 be set higher than the conservative suggestion of 53,000 1+ animals.

3.2.2 Other species

The Working Group agreed that commercial hunt of bearded seals should be banned in 2001, as in previous years, but it recommend to start catch under permit for scientific purposes to investigate results of long time protection.

3.3 Biological reference points in seal management

Based on a request from the Joint Norwegian-Russian Fisheries Commission, WGHARP discussed B _lim, B _msy and other reference points, and their applicability considered in the management of NE Atlantic harp and hooded seals, at the October 2000 meeting in Copenhagen. From the input given from WGHARP, ICES/ACFM stresses that it is important to differentiate target and limit reference points for biological characteristics of stocks. The choosing of target reference points is dependent upon the management strategy intended. Currently, replacement yield and sustainable yield imply a strategy where managers wish to maintain a population at its current size. Hence, they function as target reference points, even if they are used as an upper constraint on catches. Replacement yields are defined as the harvest in year t that will result in N _t+1 = N _t. Sustainable yields are defined as a constant harvest that will result in a stable population within a 10 – 20 year period. The resulting population is usually similar to the current population. If managers had other objectives than maintenance of current abundance, they would request other yield options, requiring other target reference points.

Limit reference points are intended to ensure that populations do not become so small that their viability is at risk. Some international fisheries agreements have suggested that as a default B _msy and F _msy may function as limit reference points. B _msy may not be appropriate to seal management for several reasons. Inadequate data are available to develop density dependent relationships. Also, the time series of abundance estimates is brief for seals and does not cover the range of population sizes necessary to determine the functional relationships underlying a B _msy approach. Moreover, application of the MSY approach requires an understanding of stock specific population response to ecosystem status (carrying capacity). Conservation biology of terrestrial mammals and birds rarely invoke MSY terminology. The discipline instead relies on methods of population viability analysis to estimate the risk of extinction. Population viability analysis requires treating many of the same considerations of density dependence and functional population relationships in a risk quantification context, without a focus on harvests.

For limit reference points that can serve as alternatives to B _msy and F _msy, the use of a specific biomass level below which recruitment is reduced (a common interpretation of B _lim within ICES/ACFM advice) is not applicable to marine mammals. In a few data-limited stocks, ICES/ACFM has used the lowest biomass from which a stock has been observed to recover as a B _lim. It may be possible to use the population dynamics model used in the assessments to back-calculate the lowest population size from which pinniped stocks have been observed to recover. These will in all cases be much larger than the population sizes at which population viability analyses would indicate that pinniped populations were at risk of collapse.

Other approaches to establishing reference points have been developed elsewhere. The two most prominent are the International Whaling Commission’s (IWC) Revised Management Protocol (RMP) and its Catch Limit Algorithm (CLA), and the U.S. Marine Mammal Protection Act’s (MMPA) Potential Biological Removal (PBR). Both have clearly defined management goals, and hence are target reference points. The IWC’s approach is designed to maximize long term yield while minimizing the likelihood that stock size will fall below a specific level. The U.S. approach uses PBR as a biological reference point for yield and the stock’s Maximum Net Productivity Level (MNPL) as the reference point for stock size. The PBR model is then designed to define a yield which allows stocks to either remain at MNPL for a prolonged period or alternatively, if the stock is reduced in abundance, allow the stock to rebuild to its MNPL.

Recognizing the need for a precautionary approach to management of seal populations, including selection of reference points, the following method for development of target and limit reference points for seal management is recommended by ICES/ACFM:

Management agencies are requested to specify the goals for seal management

During a proposed pinniped population modeling workshop (under the sponsorship of WGHARP), a session will be held to consider the quantification of density dependent responses in seal population dynamics, and the role of such processes in seal management

Risk assessment should be incorporated into the population models applied to seal stocks. The precise form of appropriate risk assessment methods remain to be determined, but will likely include the estimation of the probabilities of reaching threshold values or trends, in addition to estimating probability distributions of abundance.

Estimates of yield based on alternative biological reference points such as the IWC’s CLA and the U.S. PBR approaches for comparison to results from the current models for NW Atlantic harp seals (replacement yield model) and NE Atlantic harp and hooded seals (long-term equilibrium model) should be prepared.

4. RESEARCH PROGRAM FOR 2001

4.1. Norwegian investigations

Provided harp seals invade the coast of North Norway also during winter in 2001, biological samples will be secured from animals taken as bycatches in Norwegian gill net fisheries.

Biological material, to establish age distributions in catches as well as reproductive and nutritive status of the animals, will, if practically feasible, be collected from commercial catches both in the Greenland Sea and in the southeastern Barents Sea also in 2001.

Studies of the ecology of harp and hooded seal pups in the Barents Sea and Greenland Sea will be continued in 2001. The long term aim of these investigations is to get a better understanding of the underlaying mechanisms determining the recruitment success from year to year for the two species. The implication of this seal pup project is biological sampling from approximately 600 harp seal pups in the southeastern barents Sea and 600 harp seal pups and 600 hooded seal pups in the Greenland Sea. Body condition data will also be secured from some of the adult seals taken in the commercial catches.

A project aimed to provide the data necessary for an assessment of the ecological role of Greenland Sea harp and hooded seals throughout their distributional area of the Nordic Seas (Iceland, Norwegian, Greenland Seas) is conducted in 2000-2002. This will be a joint effort for the four NAMMCO-countries Greenland, Iceland, Faroes and Norway. In 2001, a research cruise to the pack-ice along the east coast of Greenland, is planned to be conducted in February/March. The objective will be to obtain data on distribution, diet and body condition from the two seal species. Simultaneously, harp and hooded seals taken by local hunters in eastern Greenland and as bycatches in other fisheries in Iceland and the Faroes, will be sampled for the same parameters in these countries.

Norway plan to conduct aerial surveys to estimate the pup production of harp seals in the Greenland Sea (West Ice) in 2002. Most probably, also tagging experiments will be done. Preparations for these activities will start in 2001.

4.2.Russian investigations.

Due to lack of financial support, Russian scientists have been unable to carry out biological sampling from 1 yr+ harp seals on the breeding grounds in the White Sea afetr 1994. If necessary funding is obtained, Russian scientists plan to execute sampling from males,females and pups on the whelping grounds, and from animals of all ages on the moulting grounds in the White Sea, to study age structure of females on whelping and moulting grounds; to study the terms of female breeding; to continue the studies of distribution and migrations in the breding period; to study the female age composition on the breeding grounds based on pelage colouring. It is furthermore intended to carry out mass tagging of the pups and an aerial survey of pups using a MI-8 helicopter in the White Sea (to study parameters such as mortality, terms of whelping, morphology, physiology, etc.). An implication of the Russian research activities in the White Sea is a capture for scientific purposes of 3000 (including 500 pups) harp seals .

It is the intention that Russian scientists in 2001 shall finish analyses and publish the results from the aerial surveys of the harp seal pup production in the White Sea in 2000.

4.3. Joint Norwegian - Russian investigations

The successsful joint Norwegian-Russian 1996 project (and a similar project during harp seal breeding in 1995) with tagging of harp seals with satellite transmitters in the White Sea will be continued with final analyses of data and joint publication of results in 2001. The experiment has given many interesting results concerning the ecology and migrations (e.g., in the southern Barents Sea and in the Kara Sea). The Working Group recommend that satelllite tagging experiments with harp seals in the White Sea are continued jointly between Norwegian and Russian scientists.

In another joint Norwegian-Russian project, using data collected by Russian scientists in the Greenland Sea in previous years, life history parameters (growth, age at maturity, fecundity, ovulation time) of harp seal females are being studied. This work will be continued with final joint publication in 2001.

Upon request, forwarded during meetings of the Joint Norwegian-Russian Fisheries Commission, one Russian scientist was invited to participate in scientific work on Norwegian sealers during March-April in 1997-1999 in the southeastern part of the Barents Sea, and in 2000 in the Greenland Sea. This Norwegian-Russian research cooperation is encouraged, e.g., by extending an invitation to Russian scientists to participate on Norwegian sealers in the southeastern Barents Sea and/or in the Greenland sea also in 2001. This would enable coordinated and joint sampling of biological material. The Working Group recommend that Russian scientists are offered the possibility to participate in Norwegian research activities in 2001 as described above.

Russian scientists suggest to repeat previous (1970 – 1980) workshops, where experience of different countries scientists concerning the determination of seal age were exchanged. For this purpose, the use of teeth from seals of known age should be used.

For completion of the proposed Norwegian and Russian research programs, the following numbers of seals are planned to be caught under special permits for scientific purposes in 2001:

_________________________________________________________________________

Area/species/category Russia Norway

__________________________________________________________________________

Barents Sea / White Sea

Whelping grounds

Adult breeding harp seal females 500 0

Harp seal pups 500 0

Outside breeding period

Harp seals of any age and sex 2000 0

Ringed seals 250 0

Bearded seals 300 0

Greenland Sea*

Whelping grounds

Adult breeding harp seal females 500** 0

Harp seal pups 500** 0

Adult breeding hooded seal females 500** 0

Hooded seal pups 500** 0

Outside breeding grounds

Harp seals of any age and sex 0 200

Hooded seals of any age and sex 0 200

Ringed seals 10* 100

Bearded seals 10* 50

__________________________________________________________________________

* If Greenland Sea quotas are allocated to Russia, these will be used for collection of biological samples

** Only possible if convenient vessel will be available

5. OTHER BUSINESS

5.1.

In the absence of vessels with accepted ice-class, scientific work on the breeding grounds in the White Sea have not been carried out since 1995. Therefore, Russian scientists ask Norway to assist in providing a suitable Norwegian vessel to be used in collections of scientific material from harp seals on the breeding grounds in the White Sea in 2001.

5.2.

Russian scientists offers the possibility for Norwegian scientists to participate in harp seal investigations on the whelping grounds in the White Sea, and the Working Group recommend that Norwegian scientists respond positive to this kind invitation.

5.3.

The Working Group recommend that Russian and Norwegian scientists unite efforts to develop techniques for studies (including abundance estimation) of white whales in the White Sea. Russian scientists offer Norwegian scientists the opportunity to take part in white whale investigations within the White Sea on a Russian vessel in 2001. The Working Group suggest that NAMMCO is requested to do an assessment of White Sea white whales.

5.4.

The northeast Atlantic stock of minke whales now counts about 112000 animals, and it is known to consume a substantial amount of fish (including commercially important species such as apelin, herring and gadoids). A joint Norwegian-Russian research program on the ecology of minke whales in REZ for a three year period has been developed. Norway has approved the program which would imply the take in REZ of 60 minke whales for scientific purposes per year during the investigation period. The Working Group recommend that Russia assist in fulfillment of the program.

5.5.

At present, the abundance of the northeast Atlantic minke whale is assessed following a six-year programme, where different parts of the total distributional area of the stock are surveyed each year. In 2001, the plan is to survey the eastern part of the Barents Sea (REZ included). To obtain a reliable and complete stock estimate, it is urgent to cover this important part of the distributional area of minke whales with sightings surveys. The Working Group strongly recommend that Russian authorities permit two Norwegian vessels to go into REZ to conduct these surveys during summer in 2001.

6. APPROVAL OF REPORT

The English version of the Working Group report was approved by the members on 16 November, 2000.