Lisa Readdy – Seabass management

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Transcript Lisa Readdy – Seabass management

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


Qualitative evaluation F (Fishing Mortality) 2010–2012

Above possible reference points

SSB (Spawning Stock Biomass) 2008–2012 Qualitative evaluation

Decreasing 1.6












Relative Fishing Mortality


Commercial landings

3 2 5 4 1 0 1985 3 2.5

2 1.5

1 0.5

0 1985 1991 1997 2003

Relative Fishing Mortality

2009 1991 1997 2003 2009 3.5








1985 1.6






Recruitment (age 0)

1991 1997 2003

Relative Stock Biomass

1991 1997 2003 2009 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.