The target has been met in the Greater North Sea, where harbour porpoise bycatch is estimated to be below the precautionary threshold of 1% of the best population estimate. The assessment is inconclusive in the Celtic Seas because harbour porpoise bycatch is likely to be below the threshold of 1.7% of the best population estimate, but it is currently estimated to be above the precautionary threshold of 1%.

Background

UK target on harbour porpoise bycatch

This indicator is used to assess progress against the following target, which is set in the UK Marine Strategy Part One (HM Government, 2012): “At the scale of the Marine Strategy Framework Directive Sub-Regions cetacean populations are in good condition: mortality of cetaceans due to fishing bycatch is sufficiently low so as not to inhibit population targets being met.”

Key pressures and impacts

The primary cause of mortality of cetaceans in the north-east Atlantic is being caught and entangled in fishing nets. Harbour porpoise and short-beaked common dolphin are the most commonly caught species in the North-East Atlantic. This indicator assessment focuses on bycatch of harbour porpoise only because the data available on short-beaked common dolphin were insufficient to construct robust estimates of bycatch.

Measures taken to address the impacts

Measures to protect cetaceans are set out in the UK Marine Strategy Part Three (HM Government, 2015). These include the monitoring of incidental capture and killing of cetaceans and to ensure, through conservation measures, that it does not have a significant negative impact on cetacean population size. European Commission regulations also require the use of acoustic deterrents (known as pingers) in identified fisheries on vessels larger than 12 meters.

Monitoring, assessment, and regional cooperation

Areas that have been assessed

This UK assessment focuses on two of the internationally agreed assessment units for harbour porpoise (Figure 1), which contain UK waters and sufficient data on bycatch. These are: across the North Sea, which covers most of the Greater North Sea Sub-Region, and the Celtic and Irish Seas, which includes the southern half of the Celtic Seas sub-region and inshore waters of the French part of the Bay of Biscay Sub-region. Bycatch has not been monitored or assessed recently in the West of Scotland assessment units because volumes are thought to be very low due in this region as a result of the regulations on fishing practices for example, the ban on the use of drift nets.

Figure 1. Harbour porpoise assessment units (as proposed by ICES, 2014)

Monitoring and Assessment methods

This assessment is based on that used by OSPAR for its Intermediate Assessment (OSPAR Commission, 2017), which uses the latest advice provided to the European Commission by the International Council for the Exploration of the Sea (ICES). Bycatch estimates are derived from estimates of annual fishing effort and counts of bycaught harbour porpoises. Bycatch is recorded by observers or by remote electronic monitoring on commercial fishing vessels as part of the UK Protected Species Bycatch Monitoring Scheme. ICES have advised caution because many caveats apply to the range of their bycatch estimates as a result of the reliability of fishing effort data and the potential for biases in the bycatch data from observers.

Assessment thresholds

The target is assessed by comparing estimates of annual total bycatch against limits agreed by the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS): Total anthropogenic removal of harbour porpoises (mortality resulting from all pressures caused by human activities) should not exceed more than 1.7% of the best available estimate of abundance; and to achieve this, bycatch should ideally be less than 1% of the best available abundance estimate and ultimately, be reduced to zero (ASCOBANS, 2006)

The best population estimate for the Greater North Sea Sub-Region is that collected during the third Small Cetaceans in European Atlantic waters and the North Sea (SCANS-III) survey in 2016 of 345,400 (confidence value: 0.18) and for the Celtic and Irish Seas is that from the SCANS-II survey in 2005 of 107,300 (confidence value: 0.30) as SCANS-III data were incomplete for this region.

Regional cooperation

This indicator assessment has been led by the UK as part of the OSPAR Intermediate Assessment (OSPAR Commission, 2017).

Further information

The main direct cause of anthropogenic mortality of cetaceans in the OSPAR Maritime Area is being caught and entangled in fishing nets (IWC, 2012; Peltier and others, 2016). This assessment is taken solely from the latest advice on the numbers of harbour porpoise that are incidentally caught and killed by fishing, provided to the European Commission by (ICES 2015a; 2016a). No additional information has been provided by OSPAR Contracting Parties.

The ICES advice is based on the output from the ICES Working Groups on Bycatch of Protected Species (ICES 2015b; ICES 2016b). The working group analysed data on incidental catches of cetaceans that the Member States are required to collect (European Commission, 2004). Data are primarily collected through observer schemes that should operate for each of the fisheries specified in the Annexes of the European Commission (2004). However, coverage of gillnet fisheries, for example, is generally low for a number of reasons. Under the European Commission (2004), monitoring is mandatory for vessels longer than 15 meters, whereas pilot studies and scientific studies are required on the vessels smaller than 15m. Most of the vessels in the European gillnet fleet are smaller than 15 meters, and the gillnet fleets of some Member States are very large, consisting of hundreds of vessels.

Assessment method

Introduction

The ICES Group on Bycatch of Protected Species collate and review data reported by the Member States to the European Commission (under European Commission, 2004), annually. Monitoring of bycatch is compulsory under European Commission (2004). These data also include data collected by monitoring schemes under Article 11 of the Habitats Directive (European Commission, 1992) that are used to monitor ‘incidental capture’ (Article 12, European Commission,1992) and to assess marine mammal conservations status (Article 17, European Commission, 1992). All data are requested by the ICES Working Group on Bycatch in a standard format and collated by the working group into a bycatch database.

Records of bycaught animals are conducted by observers on fishing vessels and are collated over several years to ensure sufficient geographical coverage. The number of observed dead animals are divided by the number of days that fishing vessels were observed to calculate a ‘bycatch rate’ (see details below). This bycatch rate is then multiplied by the number of days that vessels were fishing in an area during the entire year to produce an estimate of total annual bycatch.

Species

This indicator assessment focuses on bycatch of harbour porpoise (Phocoena phocoena) only. Of those cetacean species reported as bycatch by European Union member states, harbour porpoise and short-beaked common dolphin (Delphinus delphis) are the most commonly bycaught species in the north-east Atlantic (for example, ICES, 2015b; 2016b). These species are the most abundant in the area, and consequently, more data on the bycatch of these two species are available compared to other species. ICES also collated bycatch data on short-beaked common dolphin in parts of the Celtic Seas, the Bay of Biscay and Iberian Coast, and the Wider Atlantic (ICES 2016a; 2016b). Bycatch rates were calculated for each of the 11 fishing gear types (métier level 4, for example: mid-water otter trawl, set gillnet, bottom pair trawl) in each ICES division VII, VIII, and IXICES (ICES 2016a; 2016b), however total annual bycatch (calculated by multiplying bycatch rates by estimates of fishing effort for each gear type) were not made. In this indicator assessment, we therefore cannot provide comparable estimates of total annual bycatch for both species.

Bycatch Risk Assessment

A Bycatch Risk Assessment approach (known as BRA) was adopted at a workshop to ‘Evaluate Aspects of EC Regulation 812/2004’ (ICES, 2010) and later elaborated by the Working Group in Bycatch in 2013 (ICES, 2013). The bycatch risk assessment aims to ’identify sea areas or fisheries that may pose the greatest threat to non-target species in the absence of reliable data that would be needed to quantify the bycatch of that species in a statistically rigorous manner’ (ICES, 2015b).

Bycatch Risk Assessment estimates the total annual bycatch of species in a region using the following parameters:

  • Bycatch rate (number of animals caught per day), which is equal to the number of bycaught animals observed divided by the number of observer days
  • Fishing effort: the number of days at sea, for any relevant fishing gear type
  • Total bycatch (number of animals caught), which is equal to the product of fishing effort and bycatch rate

The ICES Working Group on Bycatch of Protected Species pooled information on bycatch rates across years due to the patchiness of coverage of the relevant fisheries in any one year. Fishing effort data were collated by the Scientific, Technical, and Economic Committee for Fisheries and others (see ICES 2015b; 2016b).

Harbour porpoise Assessment Units

ICES (2014) recommended five assessment units for harbour porpoise to OSPAR. The boundaries of these assessment units are mostly consistent with ICES subarea/division boundaries (see Figure 1) with the exception of the boundary between the North Sea and the Kattegat:

1) North Sea: ICES Subarea IV, Division VIId, and part of Division IIIa (Skagerrak) (includes most of OSPAR Region II)

2) Kattegat and Belt Seas: part of the ICES Division IIIa (Kattegat) and Baltic Areas 22 and 23 (includes easternmost part of OSPAR Region II and the Belt Seas, which lie outside the boundary of the OSPAR Maritime Area);

3) Western Scotland and Northern Ireland: ICES Division VIa and Subdivision VIb2 (includes the northern half of OSPAR Region III);

4) The Celtic Sea and Irish seas: ICES Subarea VII with the exception of Division VIId (includes southern half of OSPAR Region III and inshore waters of the French part of OSPAR Region IV. Note that there are very few harbour porpoises in the deeper parts of OSPAR regions III and IV);

5) Iberian Peninsula: ICES Divisions VIIIc and IXa (includes the Iberian coast in OSPAR Region IV).

Harbour porpoises are distributed throughout the Belt, Kattegat and Skagerrak Seas, the shelf waters of the Greater North Sea, the Celtic Seas and the Bay of Biscay, and Iberian Coast. In this area, the following three distinct populations are found:

  • the Belt Sea population inhabiting the southern part of Kattegat Sea, the Belt Sea, and the southwestern Baltic Sea during summer constitutes a separate population (Sveegaard and others, 2013),
  • the greater North East Atlantic/North Sea population including the northern Kattegat Sea and the Skagerrak Sea, and
  • the Iberian coast (Fontaine and others, 2007).

This UK assessment focuses on only those assessment units that contain UK waters and where there were sufficient data for ICES to estimate bycatch rates: the North Sea (covering most of the Greater North Sea, except Kattegat) and the Celtic Seas and French part of the Bay of Biscay.

Harbour porpoise bycatch estimation

The ICES Working Group on Bycatch of Protected species collated observer data for net fisheries to calculate bycatch rates in three out of the five ICES assessment units for harbour porpoise (ICES, 2015b, 2016b). Annual bycatch rates for the North Sea the Celtic and Irish seas assessment units were calculated from observer data pooled over the period from 2006 to 2013 (ICES, 2015b). Within each ICES Sub-division, the 95% confidence interval around the estimated bycatch rate was calculated (for methods see ICES, 2015b). Data in each sub-division were then aggregated to calculate an overall bycatch rate for each assessment unit.

Fishing effort by fleets (total number of days at sea) was summarised in each assessment unit in 2013. Data on fishing effort (number of days at sea) were collated across all ‘net’ level 4 métiers: trammel nets, set nets and driftnets , across all seasons and all vessel length categories. The lower and upper 95% confidence limits of the bycatch rate were then multiplied by the fishing effort to generate a range of possible annual bycatch totals for each assessment unit.

The effort data and the observations of harbour porpoise bycatch cover a wide range of vessel types and fishing areas. In their estimation of bycatch rates and fishing effort, the ICES Working Group on Bycatch of Protected Species stated that ‘no account is taken of any spatial heterogeneity or differences in mesh sizes or other important gear characteristics' (ICES, 2015b).  nature and diversity of the gillnet fisheries within each assessment region, and this is not likely to be true (ICES, 2015b). For this reason, a range of numbers have been used to highlight the uncertainty in the overall bycatch estimate within each assessment unit (ICES, 2015b). This approach does not address several potential biases. An examination of these will require detail of the fleet structure and how the observations are stratified (ICES, 2015b).

Abundance estimates

To assess bycatch rates in relation to the UK targets, the estimates of total bycatch of harbour porpoise in each assessment unit were compared against the best abundance estimate. The best estimates of abundance for harbour porpoise in the Greater North Sea is taken from preliminary analysis of the results from Small Cetaceans in European Atlantic waters and the North Sea SCANS-III survey conducted in 2016 (Hammond and others, 2017). The best abundance estimates of the Celtic and Irish Seas assessment unit is taken from the SCANS-II survey conducted in 2005 (Hammond and others, 2013). The preliminary estimate from SCANS-III for the Celtic and Irish Seas was not considered the best estimate for this assessment unit because it is derived from data only from UK waters and not yet from Irish waters and is therefore incomplete. During SCANS-II, there were more harbour porpoise in Irish waters than there were in the UK waters of the Celtic and Irish Seas assessment units.

Results

Findings from the 2012 UK Initial Assessment

Overall in UK waters, harbour porpoise bycatch was below 1.7% of the best abundance estimate. Bycatch had declined in the North Sea and the Irish Sea due to a decline in the static net fishing effort (HM Government, 2012).

Latest Findings

Status assessment

In both sub-regions, bycatch was below the Agreement on the Conservation of Small Cetaceans off the Baltic and North Seas limit of 1.7% for ‘total anthropogenic removal’. However, in the Irish and Celtic Seas assessment unit, harbour porpoise bycatch had exceeded the precautionary objective to reduce bycatch to less than 1% of the best available abundance estimate. Table 1 shows the number of harbour porpoise that were estimated by ICES to have been killed by commercial fishing nets in the North Sea and the Irish and Celtic Seas assessment unit in 2013.

Table 1. Harbour porpoise bycatch mortality from fishing nets in each assessment unit, compared against the best estimate of abundance (ICES, 2016a). The best abundance estimate for the North Sea is taken from a preliminary analysis of the results from the Small Cetaceans in European Atlantic waters and the North Sea SCANS-III survey, while that for the Celtic and Irish Seas is taken from reanalysis of SCANS-II survey data.

Porpoise assessment unit

North Sea

Celtic and Irish Seas

Estimated total porpoise bycatch 95% CLs (2013)

1,235 - 1,990

1,137 - 1,472

Best abundance estimate (year)

345,400 (confidence value: 0.18)

(2016)

107,300 (confidence value 0.30)

(2005)

Annual bycatch as a percentage of the best abundance estimate

0.36-0.58 %

1.06-1.37 %

Trend Assessment

No trends in estimated annual bycatch are available.

Further information

The estimated total porpoise bycatch from ICES (2016a) (shown in Table 1) was estimated as the lower and upper 95% confidence limits rather than a single value. The confidence intervals were used to better reflect uncertainty in the estimates of overall bycatch within each assessment unit. ICES consider this uncertainty to result from the following:

  1. The data on fishing effort (as the number of days spent at sea) are likely to be underestimated as the effort from smaller commercial vessels (particularly those less than 10 meters in length), from recreational vessels, from fisheries not represented in the data, and from the beach are not accounted for This leads to underestimates in bycatch.
  2. The bycatch rates may be overestimated as the majority of bycatch records were collected by observers on large vessels (more than 15 meters in length) that use more gear than smaller vessels and may therefore have a higher likelihood of catching cetaceans.
  3. The data on fishing effort and the bycatch records from observers on vessels cover a wide range of vessel types and fishing gear types (trammel nets, set gillnets and driftnets). No account was taken of any spatial heterogeneity (patchiness), or of any differences in mesh sizes, net length, or other important gear characteristics. ICES point out ‘there is an implicit assumption that the summarized observations are representative of the nature and diversity of the gillnet fisheries within each assessment region, and this is not likely to be true’.

ICES concluded that their approach to estimating bycatch ‘does not address several potential biases. An examination of these will require detail of the fleet structure and how the observations are stratified’.

Confidence has been rated as moderate/low for the method of this assessment and low for data availability. Table 2 contains the values that were used by ICES, (2016) to estimate the total porpoise bycatch given in Table 1.

Table 2. Harbour porpoise bycatch mortality from fishing netsa in each assessment unit, compared against the best estimate of abundance. Observations of bycatch on fishing vessels were pooled over the time periods shown because of the patchy coverage of relevant fisheries in any one year. aData on fishing effort (as number of days at sea) were collated across all ‘net’ level 4 métiers: trammel nets, set nets and driftnets,, across all seasons and all vessel length categories. bBycatch rates are rounded to the nearest three decimal places; total bycatch was estimated using bycatch rates that were not rounded (ICES, 2016a). cTaken from a preliminary analysis of the results from Small Cetaceans in European Atlantic waters and the North Sea SCANS-III survey. dTaken from reanalysis of SCANS-II survey because SCANS-III data are incomplete.

Porpoise assessment unit

North Sea

Celtic and Irish Seas

No. observer days (2006-2013)

1398

3207

No. bycaught porpoise observed (2006-2013)

50

147

Bycatch rate (no. animals caught per day during 2006-2013)b

0.028-0.045

0.035-0.045

Fishing effort days-at-sea (2013)a

44,165

32,930

Estimated total porpoise bycatch 95% CLs (2013)

1,235 - 1,990

1,137 - 1,472

Best abundance estimate (year)

345,400 (cv = 0.18)c

(2016)

107,300 (cv = 0.30)d

(2005)

Annual bycatch as a percentage of the best abundance estimate

0.36-0.58%

1.06-1.37%

Conclusions

The target has been met in the North Sea, where harbour porpoises are returning to the southern North Sea and eastern Channel, and where harbour porpoise bycatch is below the precautionary threshold of 1%. The assessment is inconclusive in the Celtic and Irish Seas assessment unit, because harbour porpoise bycatch has remained below the threshold of 1.7% of the best population estimate, but it is above the precautionary threshold of 1%. While monitoring of the UK fishing fleet is good, there is low confidence in the bycatch estimates due to incomplete monitoring of bycatch across all fleets impacting the populations.

The current bycatch estimates are derived from observing only 0.28% of the fishing effort for the fishing gear types classified as ‘nets’. A higher observer coverage in dedicated surveys would also improve the reliability of future estimates of bycatch rate.

Further information

This bycatch assessment is of harbour porpoise (Phocoena phocoena) only. ICES (2016a; 2016b) have also collated bycatch data on short-beaked common dolphin (Delphinus delphis) in ICES divisions VII, VIII, and IX, which include parts of the Celtic Seas, Bay of Biscay and Iberian coast, and the Wider Atlantic. A total of 2,509 common dolphins were recorded killed during 13,746 observer-days. ICES (2016a) caution that the total observed common dolphin bycatch is ‘based upon information that is not complete. It is not known if these estimates are biased (nor the direction of any bias), so this advice cannot yet be regarded as definitive.’ This lack of confidence in the data meant that ICES (2016a; 2016b) did not estimate total annual bycatch by multiplying bycatch rates by estimates of fishing effort for each gear type. Hence, we could not use the preliminary results for common dolphin in a way that was comparable to that used for harbour porpoise. Furthermore, a recent study indicates that bycatch numbers for common dolphin inferred from stranding schemes are much higher than data from observer schemes suggest (Peltier and others, 2016).  However, the more recent SCANS-III population estimate (Hammond and others, 2017)  is considerably higher than the Peltier and others (2016) analysis.

Knowledge gaps

The bycatch estimates provided by ICES represent the best available. However, confidence in future assessments would be enhanced by more accurate estimates of bycatch rate and of fishing effort. For example, more accurate bycatch rates could be obtained by observing bycatch on a sample of vessels that represents the wider fishing fleet in terms of fishing gear types, vessels sizes, and distribution of fishing activity over space and time and differences in porpoise density.

Further information

Marine mammal bycatch monitoring

During their review of bycatch reports by the European Union Member States, ICES (2015) found that the monitoring of bycatch by observers on fishing vessels varies over space and time. Monitoring of bycatch in set gillnets, trammel nets, and drift nets (fishing métier level 4), the most lethal gear to harbour porpoise, is mandatory on vessels over 15 meters in length, yet the majority of vessels using these gear types in the North East Atlantic measure less than 15 meters. This results in bycatch estimates with unquantified bias and generally wide confidence intervals, which diminishes the confidence in reported impacts on the population.

More accurate bycatch rates could be obtained by observing bycatch on a sample of vessels that represents the wider fishing fleet in terms of fishing gear types, vessels sizes, and distribution of fishing activity over space and time, along with differences in porpoise density. ICES have suggested that fishing effort could be more accurately recorded using measures of ‘net meter per day.’ This, or a similar metric could more precisely record fishing effort than ‘days at sea,’ for net types. such as set gillnets that are more likely to catch harbor porpoise than mobile gear such as trawls. Information on net length and soak time are rarely reported in fishing effort statistics.

References

ASCOBANS (2006) ‘Incidental Take of Small Cetaceans’ Resolution, 12 December 2016, document number UNEP/ASCOBANS/Resolution 5.5 (viewed on 26 November 2018)

European Commission (1992) ‘Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora’ Official Journal of the European Union L 206, 22.7.1992, pages 7-50 (viewed 1 October 2018)

European Commission (2004) ‘Council Regulation (EC) No 812/2004 of 26.4.2004 laying down measures concerning incidental catches of cetaceans in fisheries and amending Regulation (EC) No 88/98Official Journal of the European Union L 150, 30.4.2004, pages 12–31 (viewed on 9 December 2018)

Fontaine MC, Tolley KA, Siebert U, Gobert S, Lepoint G, Bouquegneau J-M, Das K (2007) ‘Long-term feeding ecology and habitat use in harbour porpoises Phocoena phocoena from Scandinavian waters inferred from trace elements and stable isotopes’ BMC Ecology 7: 1 (viewed on 9 December 2018)

Hammond PS, Macleod K, Berggren P, Borchers DL, Burt L, Cañadas A, Desportes G, Donovan GP, Gilles A, Gillespie D, Gordon J, Hiby L, Kuklik I, Leaper R, Lehnert K,  Leopold M, Lovell P, Øien N, Paxton CGM, Ridoux V, Rogan E, Samarra F, Scheidat M, Sequeira M, Seibert U, Skov H, Swift R, Tasker ML, Teilmann J, Van Canneyt O, Vázquez JA (2013) ‘Cetacean abundance and distribution in European Atlantic shelf waters to inform conservation and management Biological Conservation, 164:107–122 (viewed 2 December 2018)

Hammond PS, Lacey C,  Gilles A, Viquerat S, Börjesson P, Herr H, Macleod K, Ridoux V, Santos MB, Scheidat M, Teilmann J, Vingada J, Øien N (2017) ‘Estimates of cetacean abundance in European Atlantic waters in summer 2016 from the SCANS-III aerial and shipboard surveys Report to ICES Working Group on Marine Mammal Ecology, 26 pages (viewed on 30 November 2018)

HM Government (2012) ‘Marine Strategy Part One: UK Initial Assessment and Good Environmental Status’ (viewed on 5 July 2018)

HM Government (2015) ‘Marine Strategy Part Three: UK Programme of Measures’ December 2015. (viewed on 5 July 2018)

ICES (2013) ‘Report of the Working Group on Marine Mammal Ecology (WGMME), 4-7 February 2013, Paris, France’ ICES CM 2013/ACOM:26, 117 pages (viewed on 6 December 2018)

ICES (2014) ‘OSPAR request on implementation of MSFD for marine mammals. Special request’ In: Report of the ICES Advisory Committee, 2014. ICES Advice 2014, Book 1, Section 1.6.6.1 (viewed on 5 December 2018)

ICES (2015a) ‘Bycatch of small cetaceans and other marine animals – Review of national reports under Council Regulation (EC) 812/2004 and other published documents’ In: Report of the ICES Advisory Committee, 2015. ICES Advice 2015, Book 1, Section 1.6.1.1 (viewed on 5 December 2018)

ICES (2015b) ‘Report of the Working Group on Bycatch of Protected Species (WGBYC), 2-6 February 2015, ICES Headquarters, Copenhagen, Denmark’ ICES CM 2015\ACOM:26, 82 pages (viewed on 5 December 2018).

ICES (2016a) ‘Bycatch of small cetaceans and other marine animals – Review of national reports under Council Regulation (EC) No. 812/2004 and other published documents’ ICES Advice 2016, ICES Special Request Advice Northeast Atlantic and adjacent seas ecoregions. Book 1, Section 1.6.1.1 (viewed on 9 December 2018)

ICES (2016b) ‘Working Group on Bycatch of Protected Species (WGBYC), 1–5 February 2016, ICES HQ, Copenhagen, Denmark’ ICES CM 2016/ACOM:27, 82 pages (viewed on 9 December 2018)

IWC (International Whaling Commission) (2012) 'Report of the Scientific Committee, 2012' Panama City, Panama (viewed on 9 December 2018)

OSPAR Commission (2017) ‘Intermediate Assessment 2017’ (viewed on 21 September 2018)

Peltier H, Authier, M, Deaville R, Dabin W, Jepson PD, Van Canney O, Daniel P, Ridoux V (2016) ‘Small cetacean bycatch as estimated from stranding schemes: The common dolphin case in the northeast Atlantic Environmental Science & Policy, 63:7-18 (viewed on 9 December 2018)

Sveegaard S, Teilmann J, Galatius A (2013) ‘Abundance survey of harbour porpoises in Kattegat, Belt Sea, and the western Baltic, July 2012 Danish Centre for Environment and Energy, 12 pages (viewed on 9 December 2018)

Sveegaard S, Galatius A, Dietz R, Kyhn L, Koblitz JC, Amundin M, Nabe-Nielsen J, Sinding MHS, Andersen LW, Teilmann J (2015) ‘Defining management units for cetaceans by combining genetics, morphology, acoustics and satellite tracking Global Ecology and Conservation 3: 839-850 (viewed on 9 December 2018)

Acknowledgements

Assessment metadata
Assessment TypeUK MSFD Indicator Assessment
 

D1/D4/D6 Biodiversity and Food Webs, Cetaceans

 
 
Point of contact emailmarinestrategy@defra.gov.uk
Metadata dateSaturday, May 1, 2021
TitleHarbour Porpoise Bycatch
Resource abstract

Common indicator assessment of marine mammal bycatch. Applicable to the Greater North Sea, Celtic Seas and the Bay of Biscay and Iberian Coast. To date, the best available estimate of total annual bycatch of harbour porpoises does not allow assessment against any assessment value due to data uncertainty (Celtic and Irish Seas; North Sea; Kattegat and Belt Seas).

The ICES Working Group on Bycatch of Protected Species pooled information on bycatch rates across years due to the patchiness of coverage of the relevant fisheries in any one year. Fishing effort data were collated by the Scientific, Technical, and Economic Committee for Fisheries and others (see ICES 2015b; 2016b).

Linkage

https://www.ospar.org/documents?v=7014

https://www.ospar.org/convention/agreements?q=harbour+porpoise&t=&a=&s=

Conditions applying to access and use

http://www.ospar.org/site/assets/files/1215/ospar_data_conditions_of_use.pdf

Assessment Lineage
Dataset metadata

https://odims.ospar.org/documents/199

Links to datasets identifiers

https://www.ices.dk/sites/pub/Publication%20Reports/Advice/2015/2015/Bycatch_of_PETS_Advice_2015.pdf

Dataset DOI

Please see metadata and links above

The Metadata are “data about the content, quality, condition, and other characteristics of data” (FGDC Content Standard for Digital Geospatial Metadata Workbook, Ver 2.0, May 1, 2000).

Metadata definitions

Assessment Lineage - description of data sets and method used to obtain the results of the assessment

Dataset – The datasets included in the assessment should be accessible, and reflect the exact copies or versions of the data used in the assessment. This means that if extracts from existing data were modified, filtered, or otherwise altered, then the modified data should be separately accessible, and described by metadata (acknowledging the originators of the raw data).

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Indicator assessment metadata – data and information about the content, quality, condition, and other characteristics of an indicator assessment.

MEDIN discovery metadata - a list of standardized information that accompanies a marine dataset and allows other people to find out what the dataset contains, where it was collected and how they can get hold of it.

Recommended reference for this indicator assessment

Ian Mitchell1, Kelly Macleod1 and Eunice Pinn1 2018. Harbour Porpoise bycatch*. UK Marine Online Assessment Tool, available at:  https://moat.cefas.co.uk/biodiversity-food-webs-and-marine-protected-areas/cetaceans/harbour-porpoise-bycatch/

* Adapted from OSPAR Intermediate Assessment 2017 on Harbour Porpoise Bycatch

1Joint Nature Conservation Committee