Sustainable Coastal Zone Management and Aquaculture

Keith Jeffery BSc. DMS.
Aquaculture and Aquatic Animal Health Business Development.
Cefas, UK

Food from aquatic environments contributes to human nutrition and health, but maintaining long-term production and supply from both wild-capture fisheries and aquaculture is challenging. Production must be sufficient, safe and nutritious but also environmentally, socially and economically sustainable. Global demands are expected to increase in future decades. Median projections suggest global human population growth by 2050 of 2.4 billion, to over 9.7 billion. Food demand is expected to rise faster than population growth, because a larger proportion of ‘middleclass’ people with greater spending power will consume more animal protein.

With wild fisheries production unlikely to increase significantly in the future, aquaculture represents the largest growing sector of global aquatic food production.

Climate change might affect food security via extreme weather events and potential reduction in land available for agriculture. Competition for terrestrial food growing space will be compounded by increasing urbanisation and demand for biofuel and animal feeds.

Sustainable aquaculture can provide food with little or no requirement for arable land whilst offering better food conversion (than terrestrial livestock), using much less feed per unit of production.

Expansion of aquaculture does have implications for coastal zone use, so strategic management and regulations are important to its future development.

Existing and Emerging Aquaculture Techniques.

Globally aquaculture produces a diverse range of species in different culture systems. Whilst some systems are long established, others are rapidly evolving the engineering and technology solutions required to make the industry sustainable. Systems likely to be found around the Arabian gulf include:

Net-pen culture, an economically efficient form of aquaculture. Species farmed around the Arabian gulf include sea-bream, tuna and groupers with future opportunity for producing snapper, pompano, amberjack and trevally. These systems come with elements of environmental risk that require appropriate management. Risks include build-up of organic waste, inappropriate use of medicines, and escapees impacting on wild fish stocks.

Offshore aquaculture development offers opportunity for expansion with increased availability of space, better background water quality, reduced environmental impacts, and less competition with other sectors. Submersible cages would reduce visual impacts and risk of wave damage resulting in stock loss, enabling finfish farming in more exposed environments. Challenges remain regarding operation offshore.

Closed floating pens are being trialled to reduce environmental impacts. Water is pumped in, rather than relying on free movement through the mesh of open net-pens. Potential benefits include capture of solid wastes, reduction and control of nutrient and chemical discharges, containment of stock, and a physical barrier preventing pathogen entry and exit.

Bivalve culture requires no supplementary feed as they filter-feed, improving water quality and providing ecosystems services. Diverse shellfish cultivation systems include floating longlines and rafts, bottom culture, and intertidal trestles and bouchet poles. Shellfish can pose food safety risks due to their tendency to accumulate toxic algae, viruses, bacteria or chemicals to levels that become harmful if consumed. This area needs careful regulation to ensure food safety.

Recirculation aquaculture systems (RAS) technology is still evolving and improving. These land-based systems operate by recirculating and filtering water. With technological improvements, reduction of capital costs, economies of scale and linkage with renewable energies, RAS offer promise for the future, especially for higher value species such as sturgeon or amberjack.

Land-based costal ponds produce various high value species such as prawns and shrimp whilst enabling partial control of environmental conditions.

Integrated multi-trophic aquaculture (IMTA) maximises the use and retention of nutrients with the emissions from fed species providing inputs (fertilizers, food) for others. The concept of IMTA is that farms combine aquaculture of finfish or shrimp with species that extract dissolved nutrients (e.g. seaweed) and suspended solids (e.g. shellfish) to create balanced systems with minimal environmental impact.

Aquaponics combines the culture of fish and plants in recirculating systems where dissolved waste nutrients are recovered by plants. These systems have a clean, green image producing food close to the markets. The challenge for aquaponics is to become commercially viable.

Regulation of aquaculture to protect the environment

National administrators must ensure that aquaculture development within coastal zones protects the environment, whilst enabling economic development and ensuring the seafood produced is healthy, nutritious and safe. Regulation includes:

  • Licensing appropriately located sites, where mitigation measures, good practices and an ecosystem approach have been implemented;
  • Monitoring with risk-based inspections to ensure operators comply with the licence authorisation;
  • Strategic Planning for marine aquaculture development, ensuring linkage with other marine industries, and that Allocated Zones for Aquaculture (AZAs) are provided;
  • Charging that ensures regulatory costs are proportionate to the business.

The aquaculture industry needs to ensure that Technology and systems are appropriate to the local environment. Management should incorporate a broader ecosystem-level approach encompassing all environmental impacts (e.g. animal health, discharges, alien species, veterinary medicines) and

operators should Liaise directly with regulators to ensure that they understand their responsibilities.

Benefits of an appropriately regulated aquaculture sector.

An appropriately regulated aquaculture sector will deliver a safe and sustainable supply of healthy seafood that contributes to food and nutritional security, increased employment, and economic growth in coastal communities. A well planned and regulated sector reduces conflicts between stakeholders ensuring long-term sustainability within the coastal zone.

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