1. Background and justification
The Tsunami on 26 December 2004 seriously devastated human lives, houses, fishing boats, and shrimp and fish farming areas along the western Andaman Sea coast in the six southern provinces of Thailand. Changes to the marine ecosystem arising from this severe event may have longer-term impacts on ecosystem functioning and the livelihoods of coastal people dependant on the Andaman sea ecosystem.
Environmental impacts included damage to coastal habitats, including coral reefs, beaches and mangroves. Preliminary studies indicate 3,146 Rai of coral reef slightly affected; 550 Rai of coral reef severely affected; 6,200 Rai of beaches affected; 1,860 Rai of mangrove slightly affected; 555 Rai of mangrove severely affected. However, these preliminary figures are from rapid underwater surveys in only some limited coral areas important for tourism. Wider investigations of the seabed, or coastal environment, which may significantly influence ecosystem functions, have not been conducted as yet.
Observations after the Tsunami incident also suggest that seawater has become clearer, similar to previous El Nino events. As a secondary effect, such changes might lead to effects on phytoplankton productivity and the primary food chain, perhaps related to the removal to the shoreline of seabed sludge or natural fertilizer normally utilized for plankton growth. Such events could be followed by rising seawater temperature (through increased transparency of water), further death of coral reefs (bleaching event), poor productivity water and further changes in the ecosystem.
Ecosystem changes may lead to further adverse effects on the productivity of the marine ecosystem, such as economically important marine animal species for fishing, or those that are subsequently used for aquaculture breeding and stocking of aquaculture facilities, such as black tiger prawn, grouper, lobster, as well as collection for the live fish trade such as mantis shrimp, swimming crabs and mangrove crabs.
Given the social and economic implications of such ecosystem changes, the primary, secondary and tertiary effects should be carefully studied. While they should be initiated urgently, such studies will need to be carried out over the long-term to understand the environmental impacts of the tsunami and environmental; management measures required to ensure recovery from this catastrophic event.
An implementing partner should corporate with the Department of Fisheries (DOF), particularly the Andaman Sea Marine Fisheries R&D Centre, to conduct a study of the long-term impact of the tsunami, and identify management solutions to address problems. In addition, an artificial reef programme should be explored as a means to promote rapid recovery of the ecosystem and recovery of the livelihoods of fishers dependant on the marine ecosystem. Another area of study could be the effect of near-shore seabed-sludge accumulation on fish cage culture sites. The sludge accumulation and shallower bottom may cause water pollution to fish cages, particularly during low tide.
2. Objectives
The main objective of the proposed study is to assess the long-term environmental impacts on coastal resources and ecosystem functioning, with an emphasis on damage to the wild catch and aquaculture of selected economic species. The second objective is to enhance the wild fishstock through widespread installation of artificial reefs.
3. Work plan
1) Survey on primary effects (seabed, coral reefs, mangrove nursery areas)
2) Survey and monitoring on secondary effects (water transparency, water temperature, primary productivity, coral bleaching, etc.)
3) Survey and monitoring on tertiary effects (catch and growth of selected economic marine species)
4) Monitoring of fish cages affected by accumulation of seabed sludge
5) Development of plan and installation of artificial reefs as appropriate
4. Inputs
1) Contributions by an implementing partner:
Artificial reef materials
2) Government contributions; (through the Andaman Sea Marine Fisheries R&D Centre)
Transportation and installation costs for artificial reef
