Lisa Readdy – Seabass management

Report
European sea bass
management
Lisa Readdy, Cefas. 18/09/2013
- What do we know about Bass
- History of the bass fishery
- Recent and future developments
Bass, what do we know?
Sea bass stock structure: current thinking
Four stock assessment areas
identified:
Do fisheries in one area
affect future catches in
another area?
Image - Ifremer
Less information available on
French nursery areas.
Development of area IV-VII commercial fishery.
Landings increased in all areas following 1989 year class and
subsequent good recruitment. Bulk of catch is by France
Discarding of sea bass in IV & VII: mainly MLS driven
% discarded greatest for UK and French otter trawls (~ 12% by weight)
Other gears very low discard rates < 1 or 2% typically
Discarding by otter trawls largest near important nursery grounds e.g. in VIId
Could be improved by more selective gears and spatial management
measures.
Recreational bass fishing: recent survey estimates
International recreational fishery
removals in IV+VII (mainly angling):
probably around 20% of total fishery
removals
Recreational fisheries information required through
EU regulations (Data collection framework)
Data for England recently collected by Sea Angling
2012 is contributing to this along with France and
the Netherlands.
Recent developments
Stock trends in area IV & VII: ICES WGCSE2013 results
2012
1.6
1.4
1.2
Relative TSB
Qualitative evaluation
F (Fishing Mortality)
2010–2012
Above possible reference
points
SSB (Spawning Stock Biomass)
2008–2012
0.8
0.6
0.4
0.2
Decreasing
Qualitative evaluation
1.0
0.0
0.0
1.0
2.0
3.0
Commercial landings
5
4
3
2
1
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0
1985
3
1991
1997
2003
1985
2009
2.5
2
1.5
1
0.5
1991
1997
2003
2009
Relative Stock Biomass
1.6
Relative Fishing Mortality
Relative Biomass
Relative F (ages 5-11)
Recruitment (age 0)
3.5
Relative recruitment
Commercial landingsin 1000 t
Relative Fishing Mortality
1.2
0.8
0.4
0.0
0
1985
1991
1997
2003
2009
1985
1991
1997
2003
2009
Expect continuing biomass decline until recruitment improves and F is reduced
towards a more sustainable value (Fmsy). 2013 assessment update shows
progressive loss of old bass (> 15 or 20 years of age) from population.
Longer term trends in recruitment and sea temperature
Cold winter
temperatures can
lead to high
mortality of 0-gp
and 1-gp bass.
Warmer period
from 1989 to early
2000s coincides
with stronger
recruitment.
Some recent
winters have been
cold - recruitment
appears low.
(2013 assessment – provisional; coastal temperatures from Cefas website)
ICES approach to data-limited stocks
For this stock the total biomass is estimated to have decreased
by more than 20% between the periods 2008–2010 (average of
the three years) and 2011–2012 (average of the two years). This
implies a decrease in commercial landings of least 20%
compared to the average landings of the last three years,
corresponding to commercial landings of no more than 3383 t.
Additionally, considering that the stock is considered
overexploited, ICES advises that commercial landings should
decrease by a further 20% as a precautionary buffer. This results
in commercial landings of no more than 2707 t in 2014.
Discards and recreation catches are not included in the
assessment at present.
• Future research and developments.
• Defra study program in support of the conservation of
Sea Bass.
• Continuation of standard data collections.
Main issues.
- Vulnerable due to slow growth and relatively late maturity.
- Bass fisheries have expanded over time.
- Commercial and recreational fisheries share the resource.
- Management has been largely by technical measures (e.g.
MLS; bass nursery areas). Commercial ban in Ireland.
- EU consulting member states on Bass management measures.

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