Measures to monitor site status

Actions to limit anthropogenic damage

In this section the information presented above will be evaluated in terms of its contribution to determining strategies for site management. There are two major aspects of management, which are considered in turn. Firstly programmes to determine the status of the CFT biotopes, and to reveal any changes beyond normal natural variation. Secondly control measures which can influence the impact of human activities within the SAC.

Monitoring of CFT biotopes can only be carried out by diving, or by the use of ROVs or manned submersibles. Given the depth range involved, usually >20 m, and the often exposed situations, diving will be demanding (and difficult to carry out in compliance with Health and Safety Regulations, though the new HSE Codes of Practice may ease this problem). The use of ROVs or manned submersibles for routine monitoring programmes is a largely untried field, with potential problems of cost, availability, and protocols. Consequently diving will be the main technique used for the immediate future (though the potential of ROVs for certain purposes is promising), and the logistics of any programme must be carefully evaluated in terms of practicalities and return for effort. This will apply particularly to the more remote and exposed SAC locations - and it may be desirable (or essential) to locate the more demanding programmes in the more accessible locations.

Two monitoring methods are recommended, to run in parallel in all (or at least in most) SACs. One method is an abundance scale assay of a check list of selected species - ACE surveys. Species will be selected using a range of criteria designed to designate those of highest ‘importance’ in each SAC, and will detect major changes in abundance of those species. Although local importance is a major factor in compiling the check list, these should be reasonably uniform on a regional basis since the universality of changes is a species’ abundance is an important guide to possible cause. The other method is a fixed-site photographic survey. This will reliably detect small changes within the quadrats, but the extrapolation of these changes to the broader biotope must be done with caution.

These programmes will serve three purposes. They will provide feedback for management - condition monitoring. However, with current knowledge their effectiveness in this role will be limited. They will detect impacts - surveillance monitoring - but to do so they must discriminate human impacts from natural variations. Thirdly they will operate as a research programme which will provide the data to enable the first two aims to be accomplished with increasing efficiency.

There are a number of human impacts which can damage CFT biotopes. Some of these impacts are unlikely to be moderated by any measures within the scope of an SAC management plan, but they must be recognised so that changes resulting from them may be discriminated from those where remedial action may be initiated. Impacts of this type are:

• Eutrophication.
• Global warming.
• Diffuse pollutants.

In contrast there are those impacts which pose a recognised risk, and which might be controlled by management measures.

• Point source pollutants - effluents, spoil dumping.
• Static gear fishing - anchoring, setting and hauling of pots, removal of target species.
• Towed gear fishing - direct damage, sediment resuspension, removal of target species.
• Sports angling.
• Commercial diving - anchoring, incidental damage, removal of target species.
• Sports diving - anchoring, incidental damage, collecting.

All of these risks can be mitigated by limiting the level of such activities, or by banning them, or by regulating the ways in which they are carried out. Decisions on banning or limiting these activities usually involve political expediency as well as biological necessity.

Point source pollutants should ideally not be a problem. They should not seriously impact upon an SAC at the time of its designation, and any new inputs should require consent agreement. The status of any existing inputs should be monitored as part of a management plan.

Static gear fishing is predominantly pot fishing for lobsters and crabs, and can present a management minefield. Many of the best CFT areas are also prime potting areas where operations have traditionally been pursued for long periods - by operatives who attract substantial local support and sympathy. Whilst evidence to date suggests than the incidental damage from potting is small, long term studies are still needed. The removal of large numbers of crabs and lobsters would of necessity impoverish the community, however, and limitation of potting, and its banning in parts of the SAC, should be a management objective. Effective change must almost certainly be by mutual agreement, and experience has shown how difficult this is to obtain. Carrots are invariably better than sticks, and there are positive arguments to propose. The creation of fishing exclusion zones in parts of the SAC may provide refuges for the more effective restocking of adjacent regions. Currently there is limited information on the success of this tactic (Dugan & Davis, 1993), though there is evidence that they have value in relation to abalone in Australia and California (Shepherd & Brown, 1993; Tegner et al., 1982), spiny lobsters in Florida (Davis & Dodrill, 1989) and sea urchins in Japan (Tegner, 1989). An SAC can also be a special attraction to visiting divers, whose transport will provide an alternative revenue for fishermen.

The use of towed gear over CFT communities would impose serious damage, and should not be allowed within an SAC. Generally such areas are only peripheral parts of dredging or trawling grounds, and the exclusion of such activities from an SAC should not impose hardship, and should be a management objective.

Sports angling may need control, especially where the bottom community is sensitive to damage by anchoring.

Commercial diving to harvest target species (e.g. sea urchins, sea fans) tends not to generate public support. A total ban would normally be the appropriate regulation measure in a SAC.

Properly conducted sports diving is not a serious risk, and diving groups are usually very amenable to sensible codes of practice. The principle of not removing specimens is generally acceptable, and incidental damage limitation is a matter of proper training. For example the British Sub Aqua Club has a comprehensive voluntary code of practice which covers most of the points which an SCA management plan would wish to make. A compulsory code of practice for sports divers in SACs is unlikely to be opposed by responsible diving organisations. Damage from anchoring tends to be less with the light ground tackle used by many dive boats (often RIBs), but in some situations the provision of permanent mooring points could pose benefits.

References