Southern Horse Mackerel ( Trachurus trachurus ) (IXa) Manuela - PowerPoint PPT Presentation

Southern Horse Mackerel ( Trachurus trachurus ) (IXa) Manuela Azevedo (IPMA) Gersom Costas (IEO) Madrid, PRAC meeting, 09 October 2014

Southern horse mackerel stock (IXa) – following results from EU project HOMSIR 2 & ICES (2004)

Southern Horse Mackerel ( Trachurus trachurus ) (IXa)  Pelagic and living inshore when young, more demersal and living offshore as it grows.  Starts spawning at 2 years old (~ 21 cm total length); spawning season from September-June; multiple spawner.  Feeds mainly on crustaceans, small fish and cephalopods - diet variations with fish length and water depth; consumed by several demersal, benthic and pelagic predators.  Caught in mixed fisheries; six fleets (PT & SP): trawl, purse-seine, artisanal .  Recruitment with occasional large peaks. • Age-based assessment . Negligible discards; commercial catches fairly accurate, 1 survey index (combined PT&SP); stock benchmarked in 2011. • No management plan 3

Fishing mortality: below F MSY (0.11) Spawning Stock Biomass: stable Recruitment: above average in 2011 & 2012 4

ICES advice Basis: F MSY approach Catch 2015: < 71 824 t 5

underestimation of SSB; overestimation of F; higher uncertanty in the estimates of recent R (missing survey index in 2012) 6

Management considerations - Limiting the increase in catch in 2015 : uncertainty in the assessment and R estimates F(2015)=F(2014)=0.046 imply Catch 2015 of 31 000 t - advised catch is for T. trachurus while TAC is set for Trachurus spp . - Fishery across fleets target mainly juvenile age classes – the exploitation pattern combined with a moderate exploitation rate does not seem to have been detrimental to the dynamics of the stock 7

Historic landings

Recent landings < TAC2013: 30 th t +17% + 4% +37%

Landings by gear and country %change=2013/2012 +60% -50% -30% +60%

F reference points - stability in the exploitation and dynamics of southern HOM; - lack of a well defined S-R relationship Conservative F MSY proxy (F 35%SPR ) WGHANSA WGHANSA 2014 2013 0.12 0.11 F 35%SPR (F MSY proxy) 0.16 0.14 F 0.1