Presently two principle sectors have been identified for aquaculture operations:
The 2.8 hectare Aquaculture Centre site is located on north bank area of the River Don and consists of lined earth ponds, and a combined productive hatchery and aquatic ecology visitor centre.
The Circle Tip is a newly created wetland system to consider cyclic fish and plant production in eco-sensitive areas and is located on a 4.7 hectare flood water retention area between the River Don and the Sheffield & South Yorkshire Navigational canal, 50 metres south-west of Denaby lock.
Aquaculture:
The principle aims are to blend innovation, research, conservation and educational awareness into a common goal of aquatic sustainability and demonstrate this through a successful commercial enterprise.
Aquatic species will be raised without need for chemical or antibiotics to control fish diseases and high protein feeds will be discouraged in favour of locally raised aquatic invertebrates.
Emphasis will be placed on the integration of aquaculture and agriculture, and research in topical areas of symbiosis for the production of foodstuffs. Principal native freshwater species will be farmed and alien cultured species assessed in relation to local environmental impact.
Wetlands:
All new initiatives in the creation of wetland habitats will be assessed with regard to their sustainable value and the increase in local biodiversity without undermining existing native species.
A planned effective system of sustainable management and the enhancement of existing wetland habitats will be financed by the sales of aquatic species. These will be sensitively harvested in wetland areas with balanced conservation management in relation to human activities.
Definition And Clarification Of Sustainable Aquaculture:
Semi-controlled Natural Aquaculture:
Utilise existing and natural ponds and lakes for the semi-controlled extensive practice of aquatic product cultivation. This exploits natural food chains and water re-cycling processes.
Although this method is environmentally friendly, it could not however sustain future global aquatic product and land management requirements.
Definition of Sustainable Aquaculture:
Sustainable aquaculture is a dynamic process, not fixed; incorporating research, learning and reassessment of methods to practice and retain natural equilibrium in aquatic ecosystems. In controlled aquatic vegetation zones aquatic species are cultured at reasonable stocking densities and maintained with natural food products and compounds.
Water quality is conserved by eco-technological methods and where applicable the need to utilise organic compounds and competent materials that are sensitive to the environment without interference in natural ecosystems.
The objective is to sustainably produce and keep pace with society’s food requirements without eroding natural capital. This will be accomplished by the integration of new technologically initiated methods and combined with effective traditional practices.
The long term aim is to produce high quality organic freshwater fish products for local markets. The positive attribute of this strategy is less expense, environmental damage caused by evasive packaging, refrigeration, transport, energy and waste associated with them.
Intensive Non-Sustainable Aquaculture:
Practices’ methods of aquaculture within an artificially controlled environment, achieving substantial production rates by unnaturally high stocking densities and intensive supplementary feeding. This system also relies upon extensive fresh water circulation and additional synthetic chemical and antibiotic requirements. Profitable cultivation is at the expense of humane animal husbandry and ecosystems.
Site Evaluation & Design:
The site comprises of damaged former colliery land interlaced with fine ecologically diverse habitats embracing woodland, rivers, wetlands and magnesium limestone outcrops. Three major water courses traverse the land namely The River Don, The River Dearne and the Sheffield & South Yorkshire navigational canal with dispersed pockets of wetland habitat throughout the site.
The Aquaculture Centre
Characteristics:
Quite by chance the location is positioned approximately 700 metres south-east from the site of a series of 18th Century fish ponds at the village of Skitholme now buried under the large coal waste area adjoining the west bank of the River Dearne.
The 5.6 hectare Phase One North sector of the site it was previously utilised for coal tipping and slurry ponds. The existing soil structure beneath the floodplain comprises of 3.0m of made ground consisting of grey sand, gravel, ash, silt, clay and other fragments of building materials.
Water quality sample statistics:
River Don water quality analysis (source Yorkshire Water Authority) The River Don sample point at Mexborough Power Station (01/01/93 to 31/12/93)
Summary of water quality analysis:
The Rivers Don & Dearne has been historically polluted since the onset of the 19th Century Industrial Revolution. Up to a period of seven years ago the rivers where evaluated as Class 4 (poor quality) water courses. Presently they exist as Class 3 rivers and expected further improvement will attain a Class 2 (fair quality) status by 1996.
Both rivers contain a high incidence of iron and other heavy metals due to mine water seepage. To accurately assess river bed pollution and the safe disposal of basal dredgings further analysis of river sedimentation is required.
Aquacultural design considerations for the centre was given to the following points:
1. Higher normal levels of heavy metals including Arsenic, Cadmium, Copper, Nickel, Zinc and water soluble Boron in the existing ground.
2. A 1.5 metre rise in flood water from the River Don based on a one in hundred year flood event.
Author:
Stephen Bedford Clark
Director of Aquatic Ecology & Sustainable Aquaculture:
