MPA Perspective: Marine Protected Areas in the North Sea

By the Fisheries Society of the British Isles

Concern has been widely expressed about fishery and other impacts on the North Sea, where the spawning stock biomass of most commercially important marine species has been reduced to less than 10% of its unexploited size and many fishery practices may be unsustainable. Besides being a source of mortality for both target and by-catch species, other effects of current fishing practices on stocks such as (i) alteration of the normal age structure, (ii) disruption of reproductive behavior, (iii) reduction in genetic diversity, (iv) habitat degradation and shifts in ecosystem structure, and (v) long-term economic losses are becoming progressively more apparent.

Conservation programs and action plans have been set up to tackle major threats such as habitat damage, biodiversity losses and declining populations as a result of overfishing. The successes of these initiatives have been variable, and the fact that efforts at international, national and local levels need to be increased to have any real impact on the problems has become increasingly clear. Most programs are based on a combination of general measures and specific actions, and one approach that has received much attention of late is to focus conservation on particular areas of sea: so-called protected areas.

The concept of using marine protected areas (MPAs) to conserve fisheries and the marine environment has come largely from studies of sedentary fish living on tropical reefs. Objectives of MPAs include stock maintenance or recovery, habitat restoration, protection of non-target species, development of recreational and educational activities, and promotion of scientific understanding. However, the environment and resources of the North Sea are quite different from those from which the MPA concept has been primarily derived, and therefore the application of MPAs in areas such as Northwest Europe needs careful consideration.

Relevant information is scarce, and the concept has had a mixed reception from the scientific community. The FSBI Briefing Paper from which this perspective piece has been excerpted discusses the extent to which MPAs conserve and protect fish stock and habitat while serving industry and other concerns. It highlights the following points:

• Many valuable fishery and wildlife species are highly mobile; thus, effects of protection on their recovery are likely to take a long time and only be significant if large areas (e.g. >70,000 sq. km) are closed to fishing. Only in such conditions could any indirect effects on their prey or other linked species be reversed.
• Sheltered locations characterized by naturally low levels of disturbance and sensitive habitats will benefit from protection from trawling. In shallow waters and exposed locations where natural disturbance by tides and wave action is high, habitats in trawled areas are expected not to differ significantly from those protected from trawling. Thus, such sites would not be good controls for fishing effects studies.
• Small MPAs can help locally protect vulnerable wildlife such as seabirds and mammals from direct effects of exploitation. They will act as foci for diving tourism and foster educational activities.
• When appropriately designed, MPAs can act as controls of exploitation effects, but only with respect to relatively sedentary organisms (species or critical life stages) and habitats adversely affected by fishing. Monitoring of these areas at appropriate scales of time and space will help determine effects of fishing as against natural and other human impacts.
• The successful design and implementation of MPAs rely on clearly defining objectives for them, and understanding the biology and ecology of the areas concerned. Furthermore, stakeholder participation in the planning, designing and implementation process is essential.
• MPAs are only one part of a suite of fisheries management measures aimed at reducing fishing mortality, which must include reduction in fishing effort, gear modification and sustainable quotas.

For more information

Fisheries Society of the British Isles, Granta Information Systems, 82A High Street, Sawston, Cambridge CB2 4H, UK. Tel: +44 1223 830665; E-mail: FSBI@grantais.demon.co.uk.