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9 Blue Jack Mackerel (Trachurus picturatus) in the waters of Azores

The T. picturatus is the only species of genus Trachurus that occurs in the Azores re- gion (northeastern Atlantic). It is a pelagic species found around the islands shelves, banks and seamounts up to 300 m depth. However, a different size structure was observed between islands shelf and offshore areas. The island shelf areas seems to function as nursery or growth zones, while the seamount/bank offshore areas as feed- ing zones where adults predominate (Menezes et al., 2006). In the Azores, the T. picturatus is exploited by different fleets and métiers. The main catches are those of the artisanal fleet that operates with several types of surface nets, the most important being the purse-seines, and bottom longline.Purse-seines are also used by the tuna bait boat fleet, which targets the T. picturatus to be used as live bait for tuna. The blue mackerel is also a very popular species among the recreational fisherman that fish along the coast of all islands. The T. picturatus landings were considerably high during the 1980’s, however chang- es in the local markets lead to a strong reduction in the catches afterwards. This re- duction was also accompanied by a sharp decrease in the fleet targeting small pelagic fish. Since this period, the catches maintained at a low level due to a voluntary auto regulation adopted by the fishermen associations. Despite this reduction in the land- ings, this fishery still has a strong impact on some fishermen communities, which directly depends on the income of this fishery.

9.1 General Blue Jack Mackerel in ICES areas The blue mackerel, Trachurus picturatus Bowdich, 1825 (Carangidae) has a broad geo- graphical distribution within the Eastern Atlantic waters and can be found from the southern Bay of Biscay to southern Morocco, including the Macaronesian archipela- gos, Tristan de Cunha and Gough Islands and also in the western part of the Mediter- ranean Sea and the Black Sea (Smith-Vaniz, 1986). It is a pelagic fish species which characteristic habitat includes the neritic zones of islands shelves, banks and sea- mounts (Smith-Vaniz, 1986). It has a schooling behaviour and prey mainly on crusta- ceans, being common in the islands of Madeira, Azores, and Canaries and Portuguese continental waters. No studies specifically addressing the existence of distinct populations in the distri- bution range of this species have been attempted so far. Some studies on growth and biological characteristics from Madeira, Azores and Canary islands (Isidro, 1990; Je- sus, 1992; Gouveia, 1993; Vasconcelos et al., 2006; Jurado-Ruzafa and Santamaría, 2012) indicated similar growth rates and reproductive season. However, biological differences on age at first maturity seem to exist between individuals from the Azores compared with those from the Madeira and Canary islands (Jesus, 1992; Jurado- Ruzafa and Santamaría, 2012). The morphometric studies carried out on T. picturatus from Azores archipelago (Isidro, 1990), western coast of Portugal (Mendes et al., 2004) and western Mediterranean (Merella et al., 1997) revealed similar population parame- ters for the estimated relationships. On the contrary, some variation was found be- tween different geographic areas in the number of soft spines from the second dorsal fin (Shaboneyev and Kotlyar 1979; Smith-Vaniz, 1986). However, meristic characters are heavily influenced by the environmental conditions experienced by the fish while

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in the larval stages, therefore in the case of migratory oceanic species, such as T. pictu- ratus, are usually considered of reduced utility for the identification of stock units. A number of studies have successfully used parasites as biological markers. Gaevskaya and Kovaleva (1985) conducted a survey of the parasites of T. picturatus from the Azores and Western Sahara. Their study identified a number of protozoan and helminth parasites showing differences in prevalence. The myxosporean Kudoa nova was found in samples from the Western Sahara, but not from banks of the Azores archipelago. Similarly, some species of digeneans (Platyhelminths: Digenea) found in the banks of the Azores, were not observed in the samples from the Western Sahara and vice-versa. The apicomplexan, Goussia cruciata which is common in T. picturatus from the Mediterranean (Kalfa-Papaioannou and Athanassopoulou- Raptopoulou, 1984) and more recently from Madeira waters (Gonçalves, 1996), was not found in the Azores or from the Western Sahara. These variations in the occur- rence of parasites could be indicative of the existence of different populations of T. picturatus. Further studies concentrating the occurrence of helminth parasites indicate some differences in both species diversity and parasitic infections levels (Costa et al. 2000, 2003). The blue mackerel is an economically important resource, especially in the Macaro- nesian islands of Azores and Madeira, where is the main pelagic fish species being caught in the local fisheries. The landings of this species in the Portuguese mainland have suffered strong fluctuations, which may be related, at least partially to fluctua- tions in abundance or availability. From 2005 to 2007 the landings have tripled, being 2007 the year with the highest landings recorded. In the Azores archipelago the land- ings have also fluctuated, while in Madeira the average of the landings from 1986 to 1991 was three times higher than the average landings from 1992 to 2007. The hy- pothesis that the fluctuations in landings can be due to changes in availability or abundance, and not just by changes in fishing effort, is supported for the Portuguese mainland by the observation of fluctuations in the abundance indices obtained from research surveys.

9.2 ACOM Advice Applicable to 2014 The advice for this stock is biennial and so the 2012 advice is valid for 2013 and 2014 (see ICES, 2012): ICES advises on the basis of the approach for data limited stocks that catches should be no more than 1800 tonnes.

9.3 The fishery in 2013 Commercial catches for 2013 include landings, discards (estimated for 2013), tuna bait catches and recreational catches. For 2013, the discards observer programme didnot occur due to financial constraints, and so the longline discards (including bait con- sumption by this fleet) were estimated taking into account the results from the previ- ous years. In 2013, length frequencies and ages from landings sampling were collected and commercial abundance indices from the main fleets catching juveniles were also tak- ing into account (LPUE_Purse-seiners and cpue_BaitBoat).

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9.3.1 Fishing Fleets in 2013 The blue mackerel is mostly landed by the artisanal fleet, using purse-seines. This fleet landings represents around 90% of the total landings and the catches about 60% of the total catches of blue mackerel, in Azores. The artisanal purse-seines fleet is composed by small open deck vessels, mostly with less than 12 meters of length overall. The composition of this fleet has remained quite stable in the recent years, with 120 vessels registered last year. The contribution of this fleet to the landings and the number of vessels of each size category, for the last 12 years is showed in Error! Reference source not found..1.

180 100 160 140 80

120 60

100 % 80 40 60 Number of vessels 40 20 20 0 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

VL0010 VL1012 VL1218 % of total Landings

Figure 9.3.1.1 Contribution of purse-seine fleet to the landings of blue mackerel in Azores, be- tween 2002 and 2013, and the number of vessels of each size category.

9.3.2 Catches Commercial catches including landings, discards (estimated for 2013), tuna bait catches and recreational catches, for the period 1978 to 2013, are presented in Error! Reference source not found.. Total estimated catches of blue mackerel in the Azores, for the considered period in Error! Reference source not found..1 (2002-2013), are around 1650 tonnes; while landings, in same period,are in average 1100 tonnes. In the last three years, the aver- age catches and landings decreased to about 1330 and 750 tonnes, respectively.

Table 9.3.2.1 – Estimated catches of blue jack mackerel (T. picturatus) by fishery, in the Azores from 1978 to 2013.

Tuna Discards/Bait Discards Year bait Recreational (LL) (PS) PS LL+Hand Total

1978 115 129 15 0 2657 78 2995 1979 118 130 15 0 4114 61 4439 1980 210 132 22 0 2920 70 3354 1981 229 135 9 0 2104 39 2516

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Tuna Discards/Bait Discards Year bait Recreational (LL) (PS) PS LL+Hand Total 1982 239 142 10 0 2429 43 2862 1983 231 142 21 0 3711 67 4172 1984 295 135 17 0 3180 62 3689 1985 303 136 11 0 3442 60 3952 1986 433 135 9 0 3282 58 3918 1987 491 139 8 0 2974 53 3666 1988 586 143 8 0 3032 55 3824 1989 352 138 9 0 2824 50 3373 1990 345 117 11 27 2472 48 3021 1991 242 115 6 127 1247 33 1770 1992 249 121 6 126 1226 35 1762 1993 375 130 22 173 1684 70 2454 1994 264 125 18 179 1745 59 2390 1995 474 119 24 182 1769 79 2648 1996 351 110 38 173 1642 123 2437 1997 259 110 31 192 1849 72 2513 1998 308 111 52 151 1387 120 2129 1999 141 119 37 35 609 84 1024 2000 83 117 23 32 602 53 910 2001 59 121 24 110 1046 55 1415 2002 82 132 28 145 1387 63 1837 2003 140 128 21 150 1455 47 1941 2004 208 111 19 125 1148 98 1709 2005 124 120 236 123 1111 120 1834 2006 264 111 40 124 1145 96 1781 2007 370 115 58 115 1032 122 1812 2008 205 110 75 111 980 139 1620 2009 230 119 115 112 1023 98 1697 2010 313 114 75 116 1021 57 1696 2011 510 118 79 105 920 62 1794 2012 399 42 41 Not 467 94 1043 available 2013 237 147 54 Not 592 123 1153 available

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2500

2000

1500

1000 Catch (ton) Catch

500

0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

PS Discards (PS) LL+Hand Discards/Bait (LL) Tuna bait Recreational

Figure 9.3.2.1 Estimated catches of blue mackerel (T. picturatus) in the Azores (ICES Subdivision Xa2) from 2002 to 2013.

An important reduction was observed in the catches of all fishing gears in 2012, but particularly for those targeting the juveniles, such as the artisanal purse-seine fleet and the tuna baitboats fleet. In the case of the artisanal seiners the reduction observed was close to 50%. The cause of this reduction is unknown. Concerning the longliners, the reduction observed in 2012 is mostly related to the practice of using the blue mackerel for bait, since their market price is too low.These values increased in 2013, although still are below the average of the preceding 10 years to 2012.

9.3.3 Effort and catch per unit of effort The fishing effort in number of days at sea is presented by year and by vessel size category in Error! Reference source not found..1.The majority of the effort is con- ducted by the small segment of the fleet (VL0010 – vessel with less than 10m), fol- lowed by the fleet segment VL1012 (vessels between 10 and 12 metres).

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6000

5000

4000

3000

Effort (days) 2000

1000

0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

VL0010 VL1012 VL1218 Total

Figure 9.3.1.1 Nominal effort (number of days) of the purse-seine fleet, total and by vessel size category for the period 2002-2013.

For the last twelve years, and with the reduction of this fleet in the 90’s, the threshold of 5000 fishing days has never been exceeded. The standardized cpue/LPUE series were updated for the small purse-seine fleet (Error! Reference source not found.Error! Reference source not found.) and the tuna baitboat fleet (Error! Reference source not found.) of blue jack mackerel, up to 2013. Landings of blue jack mackerel from the longliners are less representative once a con- siderable part of the catch is not landed being either discarded or used as bait. The source of data for updating CPUE series from this fleet is through the discards ob- server sampling programme but, since it wasnot possible to conduct it in 2013, the CPUE series for the longliners was not updated.

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600

500

400

300

Kg/day fishing 200

100

0 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013

Observed LPUE Stnd LPUE

Figure 9.3.3.2 Standardized and observed LPUE for blue jack mackerel from the Azores small purse-seine fishery, for the years 1980-2013. Broken lines indicate 95% confidence intervals.

450 400 350

300 250 200

Kg/day fishing 150 100 50 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Stnd CPUE Observed CPUE

Figure 9.3.3.3 Standardized and. observed CPUE for blue jack mackerel from the Azorean baitboat tuna fishery, for the years 1998-2013. Broken lines indicate 95% confidence intervals.

9.3.4 Catches by length Size frequencies for the jack mackerel caught in the Azores are available since 1980. In Error! Reference source not found., is presented the size distribution of the landings (catch at size) for the years 2002 to 2013. The two main fisheries target on different size categories, the surface fleets catches the juvenile fraction of the population while the longliners target the adult stock.

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16000000 14000000

12000000 10000000 8000000 6000000 4000000 CAS (Numbers of of fish) CAS (Numbers 2000000 0 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 cm

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Figure 9.3.4.1 Annual size frequencies of the catches of blue mackerel (T. picturatus) in the Azores, from 2002 to 2013.

Assessment of the state of the stock The assessment method is described in the stock annex.

9.4 Management considerations The Regional Administration intends, during the current year, put in place a specific management measure for the purse-seine fleet with the aim of regulate markets. This measure allows only 200kg per vessel, per day: Also states that fishing and conse- quent landings shall also be forbidden on weekends.