Optimum coral reef resource use: case study of a marine protected area
A protected area, Mombasa Marine Park and Reserve was established in 1986, in an area that was previously fished. Exclusion of fishermen was however not fully achieved until 1990. This study was conducted between 1992 and 1993 in an attempt to determine the conservation area design and management guidelines which maximise resource protection and optimise economic returns without adverse effects to the coral reef ecosystem. The study considered tourism, space needs for various fish guilds and fisheries yield. Tourism in Mombasa Marine Park earned 36% of all revenue accruing from Marine Parks and Reserves in Kenya. Tourist activities in the sea were concentrated in an area estimated at 5 km-. From the questionnaire survey, over 72% of the tourists indicated this area to be in either satisfactory or excellent condition. There was no statistically significant difference between the park and the reserve in terms of predation (percentage of tethered sea urchin eaten). The difference in predation between the coral and sea grass-zones was significant in the reserve. In the park, one site (across the channelj.shows significant difference but the other (wreck) shows no difference. In terms of herbivory (percentage of sea grass blade eaten), both the park and the reserve show no significant difference in general. Similarly, the reserve does not show any difference in herbivory lev-elsbetween the coral and sea grass zone, whereas the park shows a significant difference. Maline parks enjoy total protection from any consumptive utilisation whereas marine reserves, allow artisanal fisheries using traditional geaL To determine changes in community structure in space and time, species turnover for damselfish and wrasse were assessed using underwater visual census techniques. For both the marine park and reserve, species turnover for the two families level off after approximately 100 days. Highest species turnover is achieved after 400 m- in the park and at 200 m' in the reserve. The species-area relationship becomes asymptotic at 600 m- for 14 species of damselfish and at 800 m' for 17 species of wrasses. ... For the families sampled, the park shows a higher species However, in tenus of diversity, the two areas show a significant difference only for damselfish but not for wrasses. The similarity indices between the park and reserve are 80.7% and 88.24% for wrasses and damselfish respectively. Artisanal fishermen have centralised landing points where a fisheries scout is deployed to collect catch data. From a sample of 25 fishing boats spread over a period of three months, it was noted that 21.3% of the total weight offish landed at the Jomo Kenyatta Public Beach landing point was not recorded/declared to the fish scout. An analysis of effort and yield data suggests that for optimum gain, the number of fishermen per fishing boat working for six hours should be 2, that is 12 man-hours. To increase protection of species diversity, revenue from tourism and support from fishermen, the size of the current park should be reduced by 3 km2and a smaller fully protected area of 1Km2 established at Ras IwatinelNyali coral gardens. This is also expected to increase fishing yield.