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ICES Advice 2011, Book 9 69
9.4.22 Advice September 2011 ECOREGION Widely Distributed and Migratory Stocks STOCK Boarfish in the Northeast Atlantic Advice for 2012 This is the first time that ICES has provided advice for boarfish. Based on precautionary considerations, ICES advises that catches in 2012 should not be allowed to increase. Stock status
Figure 9.4.22.1 Boarfish in the Northeast Atlantic. Landings (000 tonnes) (left panel). Recruitment estimates (age 1) from
two surveys: EVOE-WIBTS-Q4 and SpGFS-WIBTS-Q4 (right panel). No analytical assessment is currently possible. Preliminary analyses suggest that fishing mortality is less than natural mortality, and that the stock is relatively large and widely distributed. Survey data suggests that recruitment has increased since 2005. Management plans No specific management objectives are known to ICES. Biology
Boarfish (Capros aper) is a small, pelagic, planktivorous, shoaling species, found at depths of 0 to 600 m. The species is widely distributed from Norway to Senegal, including the Mediterranean, Azores, Canaries, and Madeira Islands. Boarfish recruit to the fishery at around three to four years of age, although the maximum age of boarfish is about 30 years (White et al., 2011). On the Celtic Sea shelf edge, spawning occurs during June and July. Boarfish are asynchronous batch spawners with indeterminate fecundity and thus, under optimal conditions, are capable of spawning over an extended period of time. Maturation occurs at 3.5 years, corresponding to a total length of about 10 cm. The maximum size of this species is about 15 cm. Boarfish length frequencies show a clear latitudinal distribution, increasing from south to north.
Environmental influence on the stock Boarfish feed primarily on Calanus helgolandicus which has increased in abundance in recent years.
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2003 2004 2005 2006 2007 2008 2009 2010
Land
ings
('00
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nnes
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Landings
F (Fishing Mortality) 2008–2010
Qualitative evaluation No overfishing SSB (Spawning-stock Biomass) 2008–2010
Qualitative evaluation Insufficient information
70 ICES Advice 2011, Book 9
The fisheries Fisheries for boarfish are conducted with pelagic trawls, and the catches are used for reduction to fish meal and oil. Most landings (~88%) come from Division VIIj (Figure 9.4.22.2). The recent expansion of the fishery was enabled by developments in the pumping technology for boarfish catches. These changes made it easier to pump boarfish ashore. The number of vessels in the fishery has been increasing, although the recent introduction of a TAC is expected to limit further effort expansion. Catch by fleet Total catch (2010) = 137 500 t, where 100% is taken by pelagic trawl. Quality considerations The exploratory assessment is uncertain as it is based on catch-at-age data only. The spatially and temporally truncated fishing season results in catch-at-age data that may be less informative of the overall population age structure. Discards are not considered to be important in the pelagic fishery, but there are indications that boarfish are discarded in demersal trawl fisheries. These data will be collated and analysed in future assessments. Scientific basis Assessment type Survey trends, catch curves, pseudo-cohort analyses. Input data Commercial catch-at-age data, EVHOE-WIBTS-Q4, and SpGFS-WIBTS-Q4
surveys. Discards and bycatch Discards are not considered to be important in the pelagic fishery. Indicators Acoustic survey (2011), distribution from WIBTS-Q4 surveys. Other information 2011 is the first year ICES is reporting on the species. Working group report WGWIDE
ICES Advice 2011, Book 9 71
9.4.22 Supporting information September 2011 ECOREGION Widely Distributed and Migratory Stocks STOCK Boarfish in the Northeast Atlantic Reference points No reference points are defined for this stock. Outlook for 2012 No assessment can be presented for this stock. Therefore, no catch projections are provided. Precautionary considerations Based on precautionary considerations, ICES advises that catches in 2012 should not be allowed to increase. Additional considerations Management considerations During the period 2008–2010, boarfish do not appear to have been overfished. However, landings have increased rapidly during these years, reaching almost 140 000 tonnes in 2010. As information on the exploitation of boarfish is preliminary, it would be cautious for catches not to increase above the average of landings (82 000 t) recorded during that period. In 2010 an interim management plan, proposed by Ireland, included a number of measures to mitigate potential bycatch of other TAC species in the boarfish fishery. A closed season from 15 March to 31 August was proposed, as anecdotal evidence suggested that mackerel and boarfish are caught in mixed aggregations during this period. A closed season was proposed in Division VIIg from 1 September to 31 October to prevent catches of Celtic Sea herring, known to form feeding aggregations in this region at these times. If catches of a species other than boarfish but covered by TAC, totaled more than 5% of the total catch, by day and by ICES statistical rectangle, then fishing must cease in that rectangle. The precautionary 2011 TAC of 33 000 t for boarfish covered ICES Subareas VI, VII, and VIII. Bottom trawl survey data suggests a continuity of distribution spanning ICES Subareas V, VI, VII, and VIII (Figure 9.4.22.3). Isolated small occurrences appear in the North Sea (ICES Subarea IV) in some years. An examination of Portuguese groundfish survey data indicated that boarfish are mostly distributed in the southwest of Portugal, with only rare occurrences in the northern parts. This suggests a potential discontinuity of the distribution of the species between ICES Division VIIIc and the southern part of Division IXa (Cardador and Chaves, 2010; Figure 9.4.22.4). Based on these results, a single stock is considered to exist in ICES Subareas IV, V, VI, VII, and VIII, a broader area than that covered by the current EU TAC. Regulations and their effects In 2010, the European Commission notified member states that the mesh sizes of less than 100 mm were illegal and that fisheries for boarfish should not be prosecuted with mesh sizes of less than 100 mm. However, in 2011, the European Parliament voted to change Regulation 850/1998 to allow fishing for boarfish using mesh sizes ranging from 32 to 54 mm. Information from the fishing industry Due to developments in the pumping technology a number of Danish and Irish pelagic vessels have targeted boarfish in recent years and encountered large quantities of boarfish in areas south of the Porcupine in ICES Division VIIj. Both fleets consider that there is a very large stock of boarfish distributed over a large area. Other fishing vessels (demersal vessels and pelagic freezer trawlers) operating in the Celtic Sea are experiencing increases in their bycatches of boarfish, which they consider a nuisance as they can damage both the quality of the catch and their nets. Since the beginning of 2010, the Danish and Irish pelagic fleets have been actively involved in providing scientific samples of boarfish and have funded a major acoustic survey in the summer of 2011.
72 ICES Advice 2011, Book 9
Data requirements Prior to 2010, commercial sampling effort was poor, with sampling conducted by only a small number of Irish and Danish vessels. Since 2010 sampling has been considered adequate, although boarfish is not currently included under the EU Data Collection Framework. A comprehensive and coordinated sampling scheme and a targeted survey are needed to provide the scientific basis for advice on this species. Uncertainties in assessment and forecast The analyses are exploratory in nature and based on limited information. Comparison with previous assessment and advice This is the first time that ICES advice has been provided for this stock. Sources Cardador, F., and Chaves, C. 2010. Boarfish (Capros aper) distribution and abundance in Portuguese continental waters
(ICES Div. IXa). WD presented to WGWIDE 2011 meeting. ICES. 2011. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 23–29 August 2010, ICES
Headquarters, Copenhagen. ICES CM 2011/ACOM:15. White, E., Minto, C., Nolan, C. P., King, E., Mullins, E., and Clarke, M. 2011. First estimates of age, growth, and
maturity of boarfish (Capros aper): a species newly exploited in the Northeast Atlantic. ICES Journal of Marine Science, 68: 61–66.
ICES Advice 2011, Book 9 73
Figure 9.4.22.2 Boarfish in the Northeast Atlantic. Irish catches by rectangle (being representative of the area
where all countries are fishing) and year.
74 ICES Advice 2011, Book 9
Figure 9.4.22.3 Boarfish in the Northeast Atlantic. Abundance in the IBTS and WIBTS surveys. Average number
of boarfish by ICES rectangle in 2007–2010. Data from PtGFS-WITS-Q4 is not included.
ICES Advice 2011, Book 9 75
Figure 9.4.22.4 Boarfish in the Northeast Atlantic. Distribution of boarfish in the Portuguese autumn groundfish
surveys (PtGFS-WIBTS-Q4) during the 2004–2009.
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
Latit
ude
(º N)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2005
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 200
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
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41.5
42.0
Latit
ude
(º N)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2004
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 1 600
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
Latit
ude
(º N)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2006
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 1 000
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
Latit
ude
(º N
)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2007
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 1 300
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
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Latit
ude
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)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2008
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 3 300
10.0 9.5 9.0 8.5 8.0 7.5 7.0Longitude (º W)
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
Latit
ude
(º N
)
Portimão
Sines
Aveiro
Peniche
Fig. Foz
Porto
Lisboa
Nazaré
Portuguese Autumn 2009
100 m200 m500 m
Boarfish (Capros aper)
kg/hour - max = 3 100
76 ICES Advice 2011, Book 9
Table 9.4.22.1 Boarfish in the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice Predicted catch
corresp. to advice TAC1 ICES landings
2001 None - None 0.12 2002 None - None 0.91 2003 None - None 0.46 2004 None - None 0.68 2005 None - None 0.18 2006 None - None 2.77 2007 None - None 18.39 2008 None - None 24.68 2009 None - None 83.69 2010 None - None 137.50 2011 None - 33 2012 No increase in catches - Weights in ‘000 tonnes. 1 EU and international waters of Subareas VI, VII, and VIII. Table 9.4.22.2 Boarfish in the Northeast Atlantic. Working Group estimates of landings by country and official
landings (tonnes).
Year Ireland Denmark UK (Scotland) Total landings Total official landings
2001 120 0 0 120 120 2002 91 0 0 91 91 2003 458 0 0 458 441 2004 675 0 0 675 501 2005 165 0 0 165 243 2006 2 772 0 0 2 772 2 765 2007 17 615 0 772 18 387 18 355 2008 21 585 3 098 0.45 24 683 24 683 2009 68 629 15 059 0 83 688 83 710 2010* 88 457 39 805 9 241 137 503 139 389 *Preliminary.
