Shellfish Culture in Ireland: development of the industry

The three most commonly cultivated shellfish species in Irish waters are Oysters, clams, and mussels.  To begin we will take a look at two of these, mussels and oysters.

Mussels (Mytilus edulis)

Mussels are filter feeders, reliant on natural food present in the water column.  Bottom culture of mussels dredges wild mussel spat and transports it in richer shallower waters, normally sandy beds, to harvest them 9-18 months later with dredger. Suspended culture is where mussels grown on vertical hanging ropes suspended from longlines or rafts. Mussel excretions are rich in nitrates, and produce a significant amount of ammonium and phosphates. These wastes change the composition of sediments beneath.  Beneath the high density of longline mussel cultivation is found a black anoxic hydrogen sulphide rich mud.  As a result the benthic fauna will be dominated by opportunistic species, while others will not survive.  There are also often significant changes to the nutrient balance of the ecosystem resulting from mussel culture.  All of these impacts result in changes in species composition and community structure in the locality, sometimes dramatically.

Bottom culture mussel beds also compete for space and food, sometimes out-competing the original inhabitants.  Overall, there can be significant ecological changes in the immediate vicinity, which conflict with wildlife in the area.  If these impacts are confined to a certain area of a bay or sea inlet, the system can generally cope with the disturbance. When operations cover a considerable proportion of the bay or inlet, impacts become more seriously damaging to the ecosystem.  For example, serious changes in the composition benthic fauna occur, breeding area for birds can be greatly reduced, and nursery areas for fish reduced. 

Oysters

Native oysters (Osterea edulis) are not as widely cultivated in Ireland as the Pacific Oysters (Crassostrea gigas).  For the former, wild oyster spat is collected from wild beds by dredging and relayed in a more productive area.  Once mature, the oysters are again collected by dredging.  This is practiced in Clew Bay Co. Mayo, Cork Harbour, Galway Bay, and Tralee Bay.  The impacts of this kind of Oyster cultivation are similar to the impacts of mussels described above.  Dredging, also carried out for the collection of mussel spat, has a whole suite of its own problems for natural ecosystems. 

There is a boom in recent years in the cultivation of Pacific Oysters.  Pacific oysters are cultivated in intertidal areas, and use either bags and trestles or bottom culture.  Impacts involved merit another paper altogether, but include the occupation of a valuable roosting and feeding ground for birds thus having an adverse effect on their survival and reproduction, and major changes in sediment composition.

Oysters and clams are involved in about 80% of licences operations in SPAs (BWI).

Development of the Industry in Ireland

The development of the Aquaculture industry in Ireland has not been subjected to any overall strategic assessment. There has been little research in Ireland to the actual impacts of shellfish aquaculture in our protected coastal habitats, including Special Protection Areas for birds and Special Areas of Conservation (Natura 2000 sites). Despite this the industry is being actively developed and promoted, with a large amount of structural fund aid used by the Irish authorities to expand the industry.  While no carrying capacity studies have been carried out for coastal areas affected, a production target for 2015 has been identified by the government.  The National Development Plan 2000-2006 earmarked some €70 million euro for the development of the industry, also in the absence of any strategic planning or environmental assessment.

DCMNR’s policy on Aquaculture states that the “overall goal for aquaculture is to support the sustainable development of the sector in order to maximise its contribution to jobs and growth in coastal communities and to the national economy”, yet in reality there is little attention paid to environmental impacts, which are core to sustainable development.  Proper planning and location of activities should proceed in a sustainable manner and at sustainable levels, according to the carrying capacity of particular areas.  Sometimes this may call for mitigation measures to be put in place in line with conservation objectives.  Balancing these needs is in the long term interest of coastal communities and sustainable development of coastal resources.

Nature protection: designations and protection, habitats

Shellfish operations rely on the natural availability of nutrients for their growth.  Those bays and inlets which are more biologically active are thus those that are preferred for shellfish operations.  It is these very bays and inlets that are also particularly rich in biodiversity, are important areas for feeding birds, and are thus the same sites chosen as Special Areas of Conservation under the Habitats Directive, Special Protection Areas for Birds under the Birds Directive (79/409/EEC), and Natural Heritage Areas.

The same sites are often internationally important coastal bays and estuaries with intertidal mud flats, particularly important for migratory waterfowl populations.  Even simple disturbance resulting from access to sites can be a serious issue, interfering with bird roosting and feeding patterns.

Under the European Habitats Directive Ireland (EC 92/43) must take steps to avoid the deterioration of natural habitats, the habitats of species and disturbance to the species for which areas have been designated.  Deterioration is the physical degradation of the habitat.  It can be directly assessed by a reduction in the area or a change in the characteristics of the habitat. Member States also have to take into consideration all the influences on the environment hosting the habitats.  If these influences result in making the conditions less favourable that it was before then deterioration can have been deemed to have occurred.

Despite these clear requirements of the Directive, shellfish operations are not assessed for their ecological impact on the conservation value of sites nor on their ability to cause deterioration. The requirements are that any project “likely to have a significant effect” on a Natura 2000 protected site “shall be subject to appropriate assessment of its implications for the site”.  Licences are referred to NPWS for comment, yet objections are rarely submitted.  In cases where NPWS make comment, licences are mostly still granted.  The Habitats Directive specifies ‘appropriate assessment’ as Environmental Impact Assessment (EIA).  In the case of Aquaculture licensing, the ‘competent national authority’ is the DCMNR.  However, EIAs are not carried out on operations in protected habitats, even though this process would allow for mitigation of impacts where necessary and the overall sensitive and sustainable development of coastal resources, communities, and special protected habitats and sites. 

It is clear, that these important directives, which protect special Irish nature sites, are being ignored by the Department of Marine and Natural Resources, which is responsible for aquaculture licensing and regulation. Despite clear legal requirements no impact assessments are undertaken of proposals, either individually or cumulatively. The regulations provide that fin-fish farms must have an Environmental Impact Statement, but for all other developments, irrespective of their location or size, the provision of an Environmental Impact Statement is a matter for the discretion of the Minister. The European Commission has already indicated their unease at the Irish situation in a Reasoned Opinion issued on the 25.10.01, where they state 'there is a failure to consistently ensure that potentially significant developments are subject to appropriate assessment'. As an expanding activity, the Commission is of the opinion, that because of weaknesses of protection of SPAs, it presents a serious risk of cumulative damage to Ireland's SPA network.

Many in the NGO sector have long been calling for new licences in protected areas to be granted, in accordance with the Directives, “only after having ascertained that [they] will not adversely affect the integrity of the site concerned”.  

Applications for licences must also be considered in conjunction with operations already licensed by the DCMNR, to ensure that cumulative impacts are considered.  Again this is not taken on by the licensing authority.  When licences are issued in protected sites, the operator is not even informed of the protected status of the site.  No conditions relating to sensitive site management in view of protected habitats are included in the licences or conditions attached.

The Water Framework Directive also requires ‘no deterioration’ in water quality.  According to the Characterisation Report of the WFD “As a consequence of the lack of distinct information pertaining to the wider impacts on water bodies imposed by aquaculture activities and that it is acknowledged that aquaculture activities have inherent risks associated with them all water bodies having licensed aquaculture activities are being classed as 2a - probably not at risk but there is insufficient information to class as not at risk.

Public participation

At present An Taisce are notified of aquaculture license applications in protected habitats, and regularly make submissions to DCMNR raising concerns about the lack of carrying capacity studies, the lack of proper assessment, and lack of consideration of sustainability and biodiversity issues.  The extent to which concerns raised are taken on board by the licensing authority is unknown.  In addition, this role is voluntary, with An Taicse gaining no recompense for monitoring applications. A range of other statutory bodies are also consulted.  There is concern that the consultation process in place under the aquaculture licensing regulations is being used as an alternative to proper assessment.

Other NGOs and members of the public are not informed of developments, other than notification of applications in local press.   This is very difficult to monitor.  Applications are not made available through DCMNR to other interested parties. In addition, details such as site suitability are not documented, and are impossible to establish based on information provided in the application form.  Other national NGOs, for example, have no way to know of license applications and the details.  

Decisions can be appealed to the Aquaculture Licencing Appeals Board, with a fee of €152.73.  An oral hearing can be requested, at a cost of €76.18, but the board have never held an oral hearing to date. In 2002, twenty five appeals to the board resulted in licences being granted, while only two appeals resulted in refusal of licences.

Recommendations & Conclusions

The situation outlined in this paper is one of serious concern for nature conservation in protected coastal habitats, for sustainable use of our natural resources, and transparency in public sector decisions.  The following recommendations are called for to address this crisis.

1.       Assessment of the impacts of shellfish aquaculture on protected species and habitats in Ireland

2. Carrying capacity studies be carried out for each bay, inlet, and estuary to determine the maximum quantity of operations that is sustainable
3. Ensure that the carrying capacity of the ecosystem is not exceeded
4. Specific criteria and guidelines for aquaculture EIA should be developed
5. Require EIA to be carried out in all protected sites, in line with conservation legislation
6. Ensure Coastal Zone Management Plans for all protected sites are published and implemented
7. Ensure that designated Nature Conservation sites are marked on the maps showing application area
8. Public register of licences published and made available by DCMNR
9. Operators to be informed of sensitive environmental issues by DCMNR
10. Conditions of good environmental practice attached to licences granted in protected areas in order to mitigate damage
11. Review Irish legislation to bring it in line with requirements of European Nature Conservation Legislation

In addition, An Taisce is calling for a moratorium of all new aquaculture licences in Natura 2000 sites, until carrying capacity baseline studies have been undertaken.  No new licences or renewals in Natura 2000 sites should be issued until conservation management plans for the sites are in place.

An overhaul to the licensing procedure, including implementation of the recommendations listed above, are essential to the sustainable development of the industry and of our coastal zone.  We need to put pressure on the competent authorities to ensure that exploitation of the resource is carried out in a sustainable manner for people and all the organisms upon which we depend.