Marine & Acquatic Biodiversity

Artificial Reefs for Sustainable Natural Resource Management

For generations, artisanal fishermen have relied on traditional knowledge to identify reefs where fishes converge for effective near shore natural resource management. KSBB has initiated a project to enhance the livelihood options of local fisherman by using this time tested knowledge of artesenal fisherman by constructing artificial reefs in the inshore region off the Kannanthura and Valiathura coasts.

The reefs help in recolonization of the coastal waters, provide artificial fish habitat and thereby help in attracting, aggregating and regenerating pelagic demersal migratory and residential fishes. An artificial reef develops into a fish habitat when barnacles, algae, oysters, mussels and other sessile organisms colonize these reefs. They provide living space and shelter from predators and a suitable substratum for attachment of eggs and thus serve as spawning ground in addition to functioning as a feeding ground.

The reefs were manually built at about 30m fathoms covering an area of 50 Sq mt at a distance of 2-3 km away from the shore using nine unused boats. The boats were sunk along with coconut peduncles to create an underwater habitat for fish with the active involvement of local fisherman. The materials used were such that benthic vegetation could aggregate quickly to ensure ecological succession and a stable ecosystem in the near future. Within four days, local fishermen who had stopped going out to sea because of the falling catch, reported that the area was teeming with fish. As the artificial reefs were deposited in the near shore areas about 2 to 3.5 km from the shore at a depth of 20 to 30 fathoms, fishermen need to spend less fuel and resources for fishing.

An increased biological productivity is indicated by a daily catch of about Rs.7,000 from the area where the artificial reefs were deposited. Commercially important species like Caranx sexfasciatus (Kannan para) and Stolephorus indicus (Kozhua) has been netted from the area which has enhanced the livelihood options of local fisherman.

People’s Artificial Reef through community participation (PAR)

The concept of PAR has its roots in traditional knowledge documented in Marine Biodiversity Register that naturally available reef areas are swarming with fishes. Fishermen use traditional knowledge to identity reefs. They use a visual triangulation method to navigate the location. PAR project funded by KSBB deployed two artificial reefs along the inshore region off the Kannanthura and Valiathura coasts of Thiruvananthpuram, Kerala. The position for deposition of reefs and the raw materials to be used were decided by fisherman based on their time tested knowledge. The reefs were manually built by fisherman using natural materials (wooden boats). An artificial reef emulates a natural ecosystem and provides living space and shelter from predators and a suitable substratum for attachment of eggs serving as spawning ground and feeding ground.  The main beneficiaries were two groups of selected fisherman from Valiathura. South Indian Fishermen Development society, an NGO actively involved in the welfare of fisher folks was assigned the implementation part. The boats were sunk along with coconut peduncles and sand bags for attracting spawning fishes. As the artificial reefs were deposited in the near shore areas about 2 to 3.5 km from the shore at a depth of 20 to 30 fathoms, fishermen need to spend less fuel and resources for fishing. An increased biological productivity as a result of aggregation is indicated by a daily catch from the area where the artificial reefs were installed.

Highlights of the project

  1. Against an initial investment of only Rs 30,000/- the revenue realized during one month alone was worth Rs.50,000/-  A short payback period was achieved due to utilization of locally available materials and community participation.
  2. Diversity of fishes includes Megalaspis cordyla, , Rastralliger kanangurta, Atula mate, Terapon jarbua, Caranx sexfasciatus and Stolephorus indicus .
  3. Monitoring is done by local people and the resources are exclusively managed by fishermen ensuring equitable sharing of benefits to the real custodians of bioresources.

    Management of Aquatic Invasive Species in Pampa Riverine System with the special emphasis to Cabomba

    The once biodiversity rich Pampa basin is now degraded and remains in a semi natural condition. Degradation of wetland habitats and hydrological regimes of the river system cause real threat to the viability of the biodiversity. The project envisaged to study alarming growth of different invasive weeds like, Cabomba, Lymnocharis Cyperus, Utricularia, Vallisneria, Limnophila heterophylla and Hydrilla verticillata along different regions of river Pampa. The project concluded suggesting physical and mechanical measures as control methods to check the growth of invasive species in Pampa river.

 

 

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