Bio-diversity

1. EXECUTIVE SUMMARY Octopuses belong to the order, Octopoda and are salt-water invertebrate animals with eight arms or tentacles. Octopus is related to squid or cattle fish and is grouped with them in the same class as Cephalopoda of the Phylum Mollusca. They are found throughout the world, but are rare in the polar-regions. They may live in shallow water or at great depths, often in rock crevices or sand burrows. Octopuses have no shell or no fins but possess well-developed heads with complex eyes that are similar to those of vertebrates and these provide them with an excellent vision. The octopuses swim by water propulsion, ejecting spurts of water from its siphon. Otherwise octopuses move by crawling. They use the adhesive suckers on their arms to pull themselves along and sometime quite briskly. Octopuses feed on smaller invertebrates and on small fish. They reproduce sexually. The female lays clusters of eggs near shores. They guard their eggs, circulate water over them and remove debris and sediment from the area. In Mauritius, Mr Claude Michel in his book Marine Molluscs of Mauritius confirmed the present of 13 Cephalopods species in our marine ecosystem. These include squids, Argonauts, Sepia, Seoiola, Sepioteuthis and octopus etc. Mr C. Michel confirmed the present of Octopus cyanea (Gray), Octopus filamentosus (Blain), Octopus macropus (Risso) and Octopus rugosus (Bosc). The local Octopus fishers commonly know only three types of Octopus, named locally as Orite disable, Orite corail and Orite mamzel, the latter has brown spots and longer tentacles. Orite corail is grayish/white in colour and generally has shorter tentacles. 2. JUSTIFICATION Sand Mining has been a practice for many years and the sand is used mainly in the construction sector while a lesser amount is used in filter beds and for other purposes. Even sand mining was restricted within the lagoon, however every year sand miners have been moving closer to the coral barrier in search of finer and looser sand. Sand mining has directly contributed in destroying the octopus habitats. The serious damage caused to vegetation has affected the growth of small fish and other small sea animals on which the octopuses are dependent for food. Illegal fishing techniques such as dynamite and underwater fishing have also largely contributed in the decrease of natural burrows. Site visits in the region of Bassin Humbert, Pointe Oscorne and Bassin Bernard revealed that burrows to harbour octopus were damaged and silted or was practically non-existent. Fishers have been using concrete blocks to create artificial habitat for octopus. On the other hand the CEB is replacing poles made of concrete by wooden poles. Disposal of the concrete poles is posing an environmental problem. The artificial burrows would be made out of used concrete electric poles of the hollow type. The Used Electric Poles would be cut into pieces of about 7-8 inches to make the main body of the ABs (Artificial Burrows). The bottom would be completely sealed with concrete, and the other end would be dome shaped leaving a central hole. (See annex 6). Former sand miners would provide the man - power for the preparation and placement of the artificial burrows in the lagoon. The total cost of this project is MRU 802,725.00. A grant of MRU 448,725.00 is being requested from the GEF/SGP. Co-funding will be sought from the Canada Fund or the National Environment Fund for a sum of MRU 250,000.00. The rest of the contribution will come from the EPCO, the CEB, and former sand miners.

Mauritius