|Source||ICES Scientific Reports/Rapports scientifiques du CIEM (2618-1371) (ICES), 2019 , Vol. 1 , N. 34 , P. 441p.|
The Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA1) met by correspondence, 3–7 June 2019, and was chaired by Alexandra Silva (Portugal). There were 13 participants from France, Portugal, Spain and UK. The main task of WGHANSA1 was to assess the status and to provide short-term catch scenarios for the stocks of anchovy in Division 9.a (components west and south) and for horse mackerel in Division 9.a. Assessments and shortterm forecasts were updated according to the stock annexes. The stock size indicator of the western component of the anchovy stock decreased 90% from 2018 (65 097 t) to 2019 (4129 t), after a period of an increasing trend since 2014. The harvest rate decreased 67% from management year 2017 (0.58) to 2018 (0.19) being below the median (0.28) of the historical time-series. The total catch in the management year 2018 for this stock component was 12 521 t, the historical maximum. This catch corresponds to an increase of 13% with respect to 2017 (11 090 t) and represents 79% of the total catch of the stock in Division 9.a. Work is on progress to defined reference points for this stock. The relative spawning–stock biomass (SSB) of the south component of the anchovy 9.a stock has fluctuated without a trend over the time-series, with most of the values above Bpa. From 2018 to 2019, the relative SSB decreased 5% but is still well above Bpa. Relative Fishing mortality (F) has fluctuated with no clear trend. From management year 2017 to 2018, relative F decreased 93%. The total catch in management year 2018 was 3249 t, a 17% decrease with respect to the 2017 catch (3788 t) and represented 21% of the total catch of the stock in Division 9.a. The historical series of SSB was corrected by removing the biomass of age 0 individuals, inadvertently included in last years’ assessment. Relative Blim = 0.31 (corresponding to Bloss in 2009) and relative Bpa = 0.50 were calculated with updated values of SSB following the procedure agreed at the benchmark. The SSB of horse mackerel in Division 9.a fluctuated from 1992, the beginning of the assessment period, to 2012–2013 and afterwards increased continuously to a historical maximum, in 2018, 888 422 t. The consistently high recruitment since 2011 has contributed to the SSB increase. Catches were 31 661 t in 2018 a 14% decrease in relation to catches in 2017. There has been a significant increase of purse seine catches and a steep decrease of bottom trawl catches in 2018. In the last two years, there has been an increase in the proportion of age-1 individuals in the catches. Fishing mortality was 0.029 year -1 in 2018, showing a 29% decrease compared to 2017. Fishing mortality has been below FMSY (0.11) over the whole time-series. The spawning–stock biomass has been above MSY Btrigger (181 000 t) over the whole time-series. Recruitment has been above the time-series average since 2011. The exploration of data on anchovy abundance-at-age from juvenile surveys IBERAS-JUVESAR and ECOCADIZ-RECLUTAS indicated the series are still short to conclude about their future incorporation into the assessments. The analyses of internal consistency of the indices and of their consistency with spring acoustic surveys showed promising results for ECOCADIZ-RECLUTAS and pointed out the need to revisit the results of some of the surveys, particularly the IBERAS_JUVESAR series.
ICES (2019). Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA). ICES Scientific Reports/Rapports scientifiques du CIEM, 1(34), 441p. Publisher's official version : https://doi.org/10.17895/ices.pub.4983 , Open Access version : https://archimer.ifremer.fr/doc/00585/69710/