Report of the Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA), 26–30 June 2018 Lisbon, Portugal

Type Scientific report
Date 2018
Language English
Ref. ICES CM 2018/ACOM:17
Other localization http://www.ices.dk/sites/pub/Publication%20Reports/Expert%20Group%20Report/acom/2018/WGHANSA/01_Report%20of%20the%20WG%20on%20Southern%20Horse%20Mackerel,%20Anchovy%20and%20Sardine%20-%20WGHANSA%202018.pdf
Author(s) ICES
Contributor(s) Duhamel Erwan, Pawlowski Lionel, Veron MatthieuORCID
Abstract

The Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA) met in Lisbon (Portugal), 26–30 June 2018, and was chaired by Alexandra Silva (Portugal). There were participants from France, Portugal, Spain and UK. The main task was to assess the status and to provide short-term predictions for the stocks of anchovy in Division 9.a, for sardine in divisions 8.c and 9.a, and in divisions 8.abd, and for horse mackerel in Division 9.a and blue jack mackerel in Division 10 (Azores). Advice for sardine in Subarea 7 is biennial and will be provided in 2019. Assessments were updated according to the stock annexes. The stock of anchovy in Division 9.a has been benchmarked in 2018. Two stock components with different dynamics were considered for assessment and advice, the western component (from Division 9.a-North to Division 9.a-Central-South) and the southern component (Division 9.a-South). As anchovy in Subarea 8 is scheduled for assessment and short-term forecast in November 2018, no preliminary or exploratory assessment was carried out in this meeting. A summary of the 2017 assessment and advice and data from 2018 surveys was presented. Information from the new spring surveys 2018, provide point estimates of anchovy biomass of 225 054 t (CV=14%) and 185 524 t for the DEPM and acoustic surveys respectively. Catches in 2017 were 26 450 t. As in previous years, the WG collected the few available data on the fisheries of anchovy in northern areas (subareas 4, 5 and 6), although no assessment is so far required for the anchovy in those regions. The western component of anchovy in Division 9a is assessed following the framework of category 3 stocks. The stock development is informed by a total biomass indicator, the sum of the biomass estimated in spring acoustic surveys, PELACUS covering Division 9.a-North and PELAGO, covering divisions 9.a-Central-North, Central-South and South. The advice is based on the ratio between the last index value and the average of the two preceding values, multiplied by the recent catch (July 2017 to June 2018). The advice is provided for the period July 2018 to June 2019. The stock size indicator shows a high increase in recent years, reaching its maximum level in 2018, 65 097 t. The harvest rate in 2017 was on the mean range of the historical time series, despite being above average for the last decade. The total catch in 2017 for this stock component was estimated at 10 094 t, the second historic high. This catch corresponds to an increase of 41% with respect to 2016 (7140 t) and represented 69% of the total catch of the total stock in Division 9.a. The southern component of anchovy in Division 9a is assessed using spawning biomass estimated by an age–length assessment model (Gadget). Input data are quarterly catches-at-length–age and length–age abundance from two acoustic surveys, ECOCADIZ (summer) and PELAGO (spring). The model does not provide reliable absolute stock estimates; therefore, the advice follows the framework of category 3 stocks. The trend-based procedure is similar to the one used for the western component using relative SSB as the stock indicator. Relative Blim = 0.23 (corresponding to Bloss in 2009) and relative Bpa = 0.38 were calculated with updated values of SSB following the procedure agreed at the benchmark. The total catch in 2017 was 4611 t, a 30% decrease with respect to the 2016 catch (6599 t) and represented 31% of the total stock catch in Division 9.a. The SSB and F have been fluctuating without a trend. SSB has been above Bpa in the last nine years. The WG assessed the sardine in divisions 8.a,b,d and sardine in divisions 8.c and 9.a. The EU is interested in having catch advice for all sardine stocks (including sardine in Subarea 7) although none of them has an EU TAC. In divisions 8.a,b,d, the stock was assessed, for the second year, based upon trends in SSB, fishing mortality and recruitment estimates from a SS3 model relying on catch and survey data (acoustic PELGAS, eggs BIOMAN and triennial DEPM survey). The advice is expressed in relative terms, due to the assessment being classified as category 2 (trends from analytical model). The spawning–stock biomass (SSB) is above MSY Btrigger. SSB has decreased from 2010 to 2012 to the lower value of the series (considered as Bpa/Bloss), fluctuated until 2016 and increased thereafter. The decrease after 2012 is not clearly related to the increase in fishing mortality in recent years. Landings were above 30 000 t between 2012 and 2014, dropping for two years and then raising up again to 30 000 t in 2017. Fishing mortality has been above Fpa since 2012. Recruitment has been variable over time. Recruitment in 2017 is well above the time-series average. Sardine in divisions 8.c and 9.a was assessed with Stock Synthesis with input catch-atage data, a combined index of abundance and age composition from acoustic surveys PELACUS, covering divisions 8.c and 9.a-North and PELAGO, covering divisions 9.a- Central-North to 9.a-South-Cadiz, and an index of SSB from a triennial DEPM survey. The Portuguese DEPM 2017 was carried out late in the spawning season. The DEPM datapoint for 2017 was not included in the assessment because the WG considered necessary to check the estimates, which should be carried out by the experts during WGACEGG meeting in November 2018. The sardine stock has decreased since 2006 and stabilized to a historical low since 2012. In 2017, the biomass, 175 449 t was 52% below Blim (337 448 t) and is predicted to have decrease to the beggining of 2018 (148 695 t). The historically low 2017 recruitment has contributed to this decrease. The series of historical recruitments 1978–2017 shows a marked downward trend until 2006 and since then, fluctuates around historically low values. Fishing mortality has been above Flim for most of the time-series but has been decreasing from a peak in 2011, for which the decrease of catches has contributed. In 2017, F= 0.17 year, is the lowest in the time-series and around Fpa. Total sardine catches in 2017, 21 911 t showed a decrease of 3% with respect to 2016 (22 702 tonnes). Sardine on subarea 7 is considered as a category 5 stock (catch only). However, data and knowledge on this stock have built in recent years, including an acoustic survey, which may potentially be used in a trend-based assessment (category 3) next year. Landings have decreased since 2004, especially since 2010 mainly due to a decrease in French landings, a trend opposite to that of the neighbour Bay of Biscay stock. The biomass estimated from the PELTIC survey (without the French part of Division 7e) shows no major fluctuations after a first strong increase from the 2013 estimates. The 2017 value is equal to 111 869 tons with a CV of 16%. The southern horse mackerel (Division 9.a) is assessed with model AMISH, with input commercial catches (international landings, ages, and length frequencies from catch sampling) and one bottom trawl survey index (combined PT and SP-IBTS-Q4) and maturity data from triennial DEPM surveys. The SSB fluctuated from 1992, the beginning of the assessment period, to 2012–2013 and increased to a historical maximum, in 2017, 737 556 t. The consistently high recruitment since 2011 has contributed to the SSB increase. Catches were 36 946 t in 2017 a 9% decrease in relation to catches in 2016. Fishing mortality has been below FMSY over the whole time-series. For the blue jack Mackerel (Trachurus picturatus) in the waters of the Azores, the WG continued with the collation of data. The stock is fished mainly in one purse-seine fishery, which mainly targets juvenile fish. The assessment is currently based on commercial abundance indices from the purse-seiners and tuna bait boat, used as indicators of stock trends. Purse-seiners lpue have an overall decreasing trend from 1978 until 2012 with a slight increase afterwards. The tuna bait boat indicator has been discontinued in 2016, because most of the tuna fleet changed fishing grounds to Madeira waters.

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