Indicator Name: Abundance and distribution each of
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- Figure 1 Draft proposed MSFD Assessment Units for harbour seals and for grey seal distribution. The boundaries will be confirmed as updated information is received from Contracting Parties.
- Figure 2 Draft proposed MSFD Assessment Unit for grey seal population size Monitoring requirement
- Indicators and parameters
- Annex 1 Current and known plans for monitoring harbour seals during the moult (from ICES 2014b).
- Annex 2 Current and known plans for monitoring grey seals during pupping (from ICES 2014b).
Spatial scope A subdivision of the European populations into Assessment Units (AU) is proposed for the whole range of both species (ICES2014a, b). Population estimates will be made at the AU level by combining site-level estimates. Harbour seal assessment units The harbour seal assessment units proposed are shown in Figure 1. It should be noted that the assessment units in the North Sea are broadly similar to the previously defined as EcoQO sub-units. Harbour seals tend to undertake relatively short excursions from their favoured haul-out sites, often less than 50 km (although they may range over much larger distances) and there is little evidence of extensive seasonal migrations. The Assessment Units for this species are therefore much smaller than that prescribed for the grey seal. Since ICES reviewed the geographical EcoQO subunits for harbour seals in the North Sea in 2009, two genetic studies have been undertaken (Islas-Villanueva et al. 2012, Olsen et al. 2014). Olsen et al. (2014) proposed a northern Skagerrak and a southern Skagerrak assessment unit, thus splitting the Skagerrak and Oslo fjord EcoQO sub-unit into two. The assessment units defined for harbour seals in Scotland were supported by the work of Islas-Villanueva et al. (2012). Although some broader genetic clustering was apparent. The structuring based on haul-out sites and associated local foraging areas is likely to be as important in the management of these populations as the maintenance of their genetic diversity. Assessments of harbour seals in the French waters of the North Sea and Channel should be made separately from those in adjacent English Waters(Fig. 1). Telemetry work undertaken in the three main French colonies suggests that harbour seals are very coastal, staying within 100 km of their haul-out site, (ICES, 2013). In Ireland, harbour seals are monitored at 14 key regional haulout sites which collectively contain 40-50% of the total population. National management units remain to be described by the relevant government authority. In the interim, a single Republic of Ireland AU is proposed. Grey seal assessment units Grey seals range more widely at sea than harbour seals and may visit multiple distant haul-out sites. (McConnell et al., 1999). Studies using flipper tags have indicated that young seals disperse widely in the first few months of life. For example, pups marked in the UK have been recaptured or recovered along the North Sea coasts of Norway, France, and the Netherlands, mostly during their first year of life (Wiig, 1986). Immigration of grey seals may account for as much as 35% of the observed population growth in the Dutch Wadden Sea (Brasseur et al., 2014) and hundreds of adults from the UK visit the area temporarily. Grey seal population size will therefore be assessed across the whole of the OSPAR regions II, III and IV as a single assessment unit (Figure 2). A single large assessment unit was not considered appropriate for considering the distribution part of the indicator M-3 grey seal because of the substantial loss of information at such a large geographic scale. Grey seal distribution will therefore be assessed using the smaller, Assessment Units already defined for harbour seals. Despite their ability to travel long distances, individual mature seals of both sexes are usually faithful to particular breeding sites, and may return to within 10–100 m of individual breeding locations (Pomeroy et al., 1994; Pomeroy et al., 2000; Hammond et al., 2008). Insights into the seasonal movement of grey seals in the UK from telemetry data indicate that grey seal breeding distribution can be considerably different from their foraging distribution during other times of the year (Russell et al., 2013). Grey seal distribution will be presented both for the breeding (i.e. colony locations) and nonbreeding seasons where this information is available. 
Figure 1 Draft proposed MSFD Assessment Units for harbour seals and for grey seal distribution. The boundaries will be confirmed as updated information is received from Contracting Parties. 
Figure 2 Draft proposed MSFD Assessment Unit for grey seal population size Monitoring requirement
The current level of monitoring in each country is described for harbour seals and grey seals in Annexes 1 and 2, respectively. There is some variation in the metrics that are monitored by different countries (see below). ICES (2014b) advised that given the proposed methods of target setting (see above), it is likely that further harmonisation of monitoring methods between Member States on the coasts of each assessment unit will be required. Harbour Seal Monitoring For harbour seals it is during the moult period that the greatest and most consistent numbers of individuals are found ashore. Abundance estimates are based on counts at moult haul-out sites which, in a few areas, can be supplemented by additional counts at pupping. If possible multiple counts should be made during the moult period and the peak count of the surveys should be used; this peak count represents a minimum number of harbour seals in a population as it includes only those animals hauled out at the time of counting. Where research provides a correction factor to convert this minimum to a estimate of total seals it needs to be applied consistently within an assessment unit. Periodically, additional replicate surveys should be performed over an extended period to assess changes in phenology (changes in the peak of the moulting season) that may necessitate a change to the correction factor or a change to survey dates. Aerial surveys rather than land-based counts are recommended for larger sites. Survey design should be reviewed and where necessary updated at regular intervals, particularly to account for changes in species range, epizootics, or other significant events. Survey frequency currently varies considerably (Annex 1), with some sites being monitored by land census every ten days (January–June) and daily from June to September, whilst others have a single aerial survey on an approximate five-yearly schedule. Grey seal monitoring Grey seal population estimates are most often based on pup counts. With sufficient understanding of population dynamics, pup counts enable the estimation of the total number of grey seals. In the UK, annual or biennial aerial surveys are used to determine the number of pups born and a population model is applied to the estimates of pup production to estimate the population size (SCOS, 2014). In the waters of some other contracting parties surveys of adults undertaken during the moulting period have proved to be more accurate for determining population size than pup counts. In most parts of the range of the harbour and grey seal, there is sufficient monitoring at haul-out sites and/or breeding colonies. In the Wadden Sea, the monitoring and management under the Trilateral Monitoring and Assessment Programme and Wadden Sea Plan (Trilateral Seal Agreement; Convention on the Conservation of Migratory Species of Wild Animals) have been established and working well over the last decades, and can support the indicators and targets for harbour seals, and (although not under CMS) also the ones for grey seals. In the UK monitoring and management has also been continuing over decades and can support the targets and indicators proposed for grey and harbor seals. Current survey frequency varies considerably across contracting parties (Annex 2), with some sites being monitored by regular monthly census and photo identification, whilst others are monitored approximately every five years.
Reporting The ICES Working Group on Marine Mammal Ecology (WGMME) were, in the past, requested by OSPAR to assess progress towards the EcoQOs on seals. ICES WGMME may be best placed to make such international assessments of indicator M-3 in the future at the scale of MSFD Asessment Units (see section 6). Assessments should be made at least every 6 years. Resources needed Costs should be relatively low, given that seal colonies are onshore. The monitoring for this indicator will also deliver the data needed for indicators M-5 (pup production) and will support indicator M-6 (bycatch). There may be some costs associated with data preparation and submission for analysis. Further work This indicator M-3 will be developed in tandem with indicator M-5 hence the future steps for both indicators are largely the same. The development of this indicator will require periodic review and updating by an international group of seal experts. Agreement by OSPAR Contracting Parties is needed on the Assessment Units proposed. The existing data for an agreed time period within each AU needs to be compiled and submitted to the ICES Seal database. Draft an assessment sheet in the format prescribed by OSPAR ICG-COBAM. Agreement is needed by OSPAR Contracting parties on which body will make future assessments. Baselines/targets may need to be reviewed for some of the AUs. References OSPAR, 2012. MSFD Advice Manual and Background Document on Biodiversity. Version 3.2. OSPAR Biodiversity Series. Available at: http://www.ospar.org/documents/dbase/publications/p00581/p00581_advice%20document%20d1_d2_d4_d6_biodiversity.pdf ICES 2013 Report of the Working Group on Marine Mammal Ecology (WGMME) 4-7 February, 2013 Paris, France. ICES CM 2013/ACOM:26 ICES 2014a. Report of the working group on Marine Mammal Ecology (WGMME). 10-13 March, 2014 Woods Hole, Massachusetts, USA. ICES CM 2014/ACOM: 27, 230pp ICES, 2014b. OSPAR request on on implementation of MSFD for marine mammals. In Report of the ICES Advisory Committee, 2014. ICES Advice 2014, Book 1, Section 1.6.6.1.Available as a separate sheet at: http://www.ices.dk/sites/pub/Publication%20Reports/Advice/2014/Special%20Requests/OSPAR_Implementation_of_MSFD_for_marine_mammals.pdf Islas-Villanueva, V., Hall, A. and Graves, J. 2012. Research in Association with New Seal Licensing System: Research on the population structure of harbour seals. Final report to the Scottish Government. 25pp. McConnell, B. J., Fedak, M. A., Lovell, P. and Hammond, P. S. 1999. Movements and foraging areas of grey seals in the North Sea. Journal of Applied Ecology 36:573–590. Olsen, M. T., Andersen, L. W., Dietz, R., Teilmann, J., Härkönen, T. and Siegismund, H. R. 2014. Integrating genetic data and population viability analyses for the identification of harbour seal (Phoca vitulina) populations and management units. Mol Ecol. 23:815–831. Pomeroy, P. P., Anderson, S. S., Twiss, S. D. and McConnell, B. J. 1994. Dispersion and site fidelity of breeding female grey seals (Halichoerus grypus) on North Rona, Scotland. Journal of Zoology 233:429–448. Pomeroy, P. P., Twiss, S. D. and Redman, P. 2000. Philopatry, site fidelity and local kin associations within grey seal breeding colonies. Ethology:899–919. SCOS. 2014. Scientific advice on matters related to the management of seal populations, 2014. Currently available on the SCOS website at http://www.smru.st-and.ac.uk/documents/2259.pdf Wiig, O. 1986. The status of the grey seal Halichoerus grypus in Norway. Biol. Cons. 38:339–349.
Annex 2 Current and known plans for monitoring grey seals during pupping (from ICES 2014b).
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