SLIDE 1
2
Southern Horse Mackerel ( Trachurus trachurus ) (IXa) Manuela - - PowerPoint PPT Presentation
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)
SLIDE 2
SLIDE 3
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
Southern Horse Mackerel (Trachurus trachurus) (IXa)
SLIDE 4
4
Fishing mortality: below FMSY (0.11) Spawning Stock Biomass: stable Recruitment: above average in 2011 & 2012
SLIDE 5
5
ICES advice Basis: FMSY approach Catch 2015: < 71 824 t
SLIDE 6
6
underestimation of SSB; overestimation of F; higher uncertanty in the estimates of recent R (missing survey index in 2012)
SLIDE 7
7
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
SLIDE 8
Historic landings
SLIDE 9
Recent landings
+17% + 4% +37% < TAC2013: 30 th t
SLIDE 10
Landings by gear and country
+60%
- 30%
+60% %change=2013/2012
- 50%
SLIDE 11
F reference points
WGHANSA 2014 WGHANSA 2013
F35%SPR
(FMSY proxy) 0.12 0.11
F0.1
0.16 0.14
- stability in the exploitation and dynamics of southern HOM;
- lack of a well defined S-R relationship