A (GLOBAL) REVIEW ON THE ECOSYSTEM SERVICES PROVIDED BY SHELLFISH AQUACULTURE
Andrew van der Schatte Olivier1, Laurence Jones2, Lewis Le Vay1, Mike Christie3 James Wilson4 and Shelagh Malham1
1 School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey. LL59 5AB. UK
2 Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Rd, Bangor LL57 2UW
3 Aberystwyth University Penglais Campus, Aberystwyth SY23 3FL
4 Deepdock Ltd, Bwthyn Y Mor, Holyhead, ANglesey, LL65 4HD
There is a growing interest in ecosystem services provided by shellfish aquaculture, in addition to direct market value. This study reviews the provisioning, regulating and cultural services provided by shellfish aquaculture. It synthesises the data available from around the world to provide values suitable for upscaling in a range of situations, and highlights knowledge gaps. The review covers a number of species including mussels, oysters and clams.
Shellfish are filter feeders, filtering water and particulates, and creating substrates which provide habitat that act as nursery grounds for other species. These supporting services underpin the other direct and indirect benefits of shellfish aquaculture. Indirect benefits include measurable increased production in finfish and invertebrates that are targeted in commercial and recreational fisheries, which use shellfish beds as nursery grounds or food sources. The shellfish themselves produce meat, pearls, mother of pearl, cultch and poultry grit. It is, however, regulating services that have generated the most interest, with the potential of using shellfish as nutrient remediators for nitrogen and phosphorus.
A number of studies have been carried out in the USA and the Baltic to assess their viability for this role. As the cost of removing nutrients from wastewater rises, shellfish can present a viable alternative approach, reducing the effect of eutrophication whilst still providing a product for either human consumption or non-food uses, such as chicken feed or fertiliser. Shellfish aquaculture additionally sequesters carbon into calcium carbonate via shell production, but so far only small-scale calculations have been carried out. Whilst regulating services are relatively well studied, there has been little to no assessment of cultural services of shellfish aquaculture, despite the large numbers of people going to seafood festivals around the world and the benefits being provided to local economies through seafood tourism. By taking an overarching approach across all ecosystem services on a broad scale, it is possible to gain an insight into the full value of shellfish aquaculture. Through scenario analysis, it is possible to evaluate the direct and indirect benefits of different aquaculture management approaches, and the wider benefits of expansion of the industry.