Transcript Fisheries Exclusion Zones – their use in Europe CEMARE

Fisheries Exclusion Zones – their use in Europe
CEMARE, CEDEM, CNR-IRMA & SOC (SOTON)
European Project VALFEZ (No. QLRT-PL 1999-01271)
Background to the study
The use of exclusion zones as management tools in fisheries, for habitat protection and for species
conservation has a long history in Europe. For fisheries management, their use is widespread and
their popularity growing in the form of marine protected areas, fishing boxes and gear exclusion
zones. It is clear that in some areas these zones have significant potential benefits with respect to
species conservation, especially where low-migratory species are concerned, and to environmental
aspects. However, with little published real analysis taking account of the links between the biology
and economics, the economic benefits to fisheries are less clear. With the current levels of interest
in exclusion zones, such modelling analysis is particularly pertinent to the debate being held in
European fisheries management.
This research project (VALFEZ), funded under EU framework 5, is examining the use and potential
of exclusion zones in the management of fisheries in Europe. As part of this work, there are several
case studies that we are examining which can be categorised as examples of where exclusion
zones have been implemented, formally proposed or suggested. Three of the case studies
discussed here which each fall into one of these categories respectively are: (i) the Gulf of
Castellamare, Sicily; (ii) the Iroise Sea, Brittany; and (iii) the Sea Bass fishery in the English
Channel.
(i) The Gulf of Castellammare
The Gulf of Castellammare is representative of a long standing fisheries exclusion zone in Europe,
located in North West Sicily (Figure 1), where it has been in place for more than 10 years.
In 1990 the Sicilian Regional Government imposed a year-round trawl ban in the Gulf of
Castellammare, aimed at rebuilding the severely depleted demersal stocks and eliminating the
conflict between the trawlers and the small-scale artisanal vessels operating in the Gulf. Currently,
fishing within the trawl ban area is restricted to artisanal and recreational vessels.
(ii) The Iroise Sea
This case study represents an official French government project aimed at ecosystem protection in an
open coastal sea where biodiversity is particularly rich. It is anticipated that any closure will have
important consequences for fisheries management, recreational activities and ecotourism.
The strategy is to create a national park in the Iroise coastal sea (west of Brittany) an area included in the
UNESCO world network of biosphere reserves for its remarkable biodiversity. The area supports a large
number of human activities, including commercial fishing (mainly using nets, pots and lines), seaweed
harvesting (Laminaria digitata figure 4) (90% of French production comes from the Iroise) and various
recreational activities (sport fishing, diving, sailing, ecotourism).
Approximately 500 professional fishermen and seaweed harvesters work in the area (most of them on
boats under 16 m.). The number of recreational boats sheltered in the marinas and small ports of the
Iroise is about 2500 and, according to a recent survey by IFREMER, 40% of the owners of these boats
are recreational fishermen. The area is frequented by more than 5000 underwater fishers and with
regards to tourism, more than 60 000 tourists visit the islands of the Iroise sea each year.
Some modelling work has already been carried out within the area and a bioeconomic model adressing
some of the problems associated with implementing a fishing exclusion zone in the Iroise sea has been
presented by Boncoeur et al. (2000/1). This model is mainly theoretical (and based on the Hannesson
model – Hannesson 2000) and while its basic assumptions are qualitatively suited to the situation in the
Iroise sea and to questions raised by the creation of a marine national park, the model lacks a real
quantitative basis at present. However the model is being developed to incorporate real data.
Figure 1: The Gulf of Castellammare, North West Sicily
Figure 4: the sea weed Laminaria digitata
The artisanal fishery of the Gulf consists of some 96 small vessels operating out of 4 harbours. The
main gear types and fishing methods are trammel nets, set gillnets, set longlines, FAD seine, squid
jigging, and small-scale purse seining. Over 80 commercial varieties of fish are caught and sold
locally, some of the more important being Red Mullet (Mullus barbatus), Picarel (Spicara flexuosa),
Sea Bream (Diplodu. sargus, D. vulgaris and Pagellus spp.), Hake (Merluccius merluccius),
Amberjack (Seriola dumerili) and Dolphinfish (Coryphaena hippurus)
The artisanal fleet have experienced reduced gear conflict since the closure of the Gulf, but are still
affected by:
• Recreational fishing, which since the mid 1990s has expanded rapidly and effectively filled the
vacuum left by trawlers.
• Effort restriction in the form of a self-imposed vessel tie-up of 45 days per year.
(iii) The English Channel Bass Fishery
Figure 2: Changes in demersal stocks
(trawl survey results)
Figure 3: Changes in demersal stocks
(trammel net survey results)
Demersal fishery resources
(trammel net surveys, -15 to -30 m )
5
50
4
CPUE (kg/500m net)
CPUE (kg/30min haul)
Demersal fishery resources
(trawl surveys, -10 to -200 m, spring aspect )
60
40
30
20
10
3
2
1
0
0
1990
total catch
1987-89
1994
1998
This case study examines a hypothetical exclusion zone in the English Channel, the aim of which is to
protect the spawning aggregations of the Seabass (Dicentrachus labrax (figure 5)). The English channel
winter fishery has historically been prosecuted by French fishing vessels. However, recently, with growing
demand in other European countries, a multi national fishery has developed. Despite this there has been
a long-standing artisanal fishery for bass in the UK along the English Channel characterised by small
vessels and low intensity fishing. Over the past decade, however, there has been a dramatic increase in
the fishing effort applied to Seabass in the English Channel exacerbated by the increased use of and
move towards mainly pair trawl gears.
1991
1992
1993
1994
1995
1996
1997
1998
1999
total catch
Effects of the trawl ban
Biological data based on experimental trawl surveys and trammel net surveys show a large increase
in demersal stocks since the ban was imposed (Figures 2 and 3). Of particular note is the increase
of abundance of shallow water species, caught with trammel nets, of 77% between 1990 and 1999
(Figure 3).
The biological frameworks for evaluation are well developed and results show that since the
implementation of the trawling ban there has been at least a 7-fold increase in overall biomass of
the Gulf. However, over the period species composition has changed, with most of the biomass
increase being for varieties classed as only ‘moderately commercial’. This may therefore have
attenuated the financial gains for artisanal fishermen.
Experimental survey work has examined biodiversity and catches from various areas both within
and outside of the reserve. This will enable a spatially explicit level of modelling to be developed. It
will be possible to model the Gulf fisheries to the level ports and harbours. Biologically the model
will focus on those species that are the most valuable commercially: two species that dominate in
the displaced trawl catches and two that are targeted by the remaining artisanal fleet. Work is being
undertaken to examine and develop length-based and age-based relationships for these four
species. The final evaluation technique used in this case study will depend upon the quality and
reliability of this biological data.
The species is highly suitable for inclusion in this study, being of very high value and being prosecuted in
a single species fishery with very little or no interaction with other fisheries in the Channel. In addition
there have been for some years now, calls for restrictions on commercial landings. The species falls
outside EU quota regulations although in the past two years both the national governments of France and
the UK have implemented strict landing controls.
There has been some significant bioeconomic modelling work done on the English Channel fisheries
recently (Pascoe 2000). As a key species in the English Channel, Sea Bass was included and modelled
in age-structured form. Modelling work within VALFEZ will use this existing work, to analyse potential
management effects on bass within the English Channel fisheries as a whole. Further, a separate single
species model will also be considered. This model being developed is to be an inter–temporal, spatially
explicit, age-structured bioeconomic simulation / optimisation model. Through the modelling process the
fishery will be examined at the level of homogeneously grouped ICES rectangles. Full data has been
collected on commercial landings of the fish over a ten year period, the biology is very well known, with
work being done by Picket and Pawson in the early 1990’s recording extensively the biology of the fish.
Figure 5: The Sea bass (Dicentrachus
labrax)
References
Pascoe, S. (ed.) 2000. Bioeconomic modelling of the fisheries of the English Channel, FAIR CT 96-1993, Final Report.
Pickett, G. & Pawson, M. Sea Bass: Biology, exploitation and conservation, Chapan and Hall Fish and Fisheries Series 12. 1994
Boncoeur et al. 2000. Costs and Benefits of implementing a marine reserve facing prey-predator interactions, Conference on the Economics of MPAs 6-7July 2000, Vancouver, Canada
Hannesson (1998) 'Marine Reserves: What Would They Accomplish ?' Marine Resource Economics 13: 159-170
For further information, contact;
Carl James CEMARE Department of Economics, University of Portsmouth, Locksway Road, Portsmouth, PO4 8JF, UK
Email: [email protected]