Reef Fisheries Dynamic in Karimunjawa National Park, Central Java

Abstract

Fisheries crisis has been occurred worldwide and become greater in several decades. There is an indication of declining fish stock in Karimunjawa according to the study conducted by The Wildlife Conservation Society Indonesia Program and Karimunjawa National Park Authority. Therefore, this study aimed to assess reef fisheries dynamic, fishing effort dynamic, fisher’s operation strategies, and fisher’s adaptation strategies in response to declining in catch rate. Data were collected from fish landing survey, underwater visual census, and focus group discussion from May to December 2011. Fish biomass was analyzed to obtain the value of maximum sustainable yield. Catch per unit effort and seasonal index were analyzed to obtain fishing effort dynamic. Mean of trophic level was analyzed to describe impact of fishing gear to fish community structure, diversity index was analyzed to describe fishing gear selectivity and descriptive analysis was used for fisher’s tactic and fisher’s adaptation strategies in respond to declining catch rate. The results showed that maximum sustainable yield (MSY) could be predicted from biomass data through equation MSY = 0,724*Biomass + 10,15 indicating heavy fishing pressure and equation MSY = 0,383*Biomass + 5,375 indicating light fishing pressure. All fishing gears used in Karimunjawa were concluded as gears with high diversity index or low selectivity of the catch. Speargun contributed to make the highest catch and catch per unit effort (CPUE) compared to others fishing gears, however handline catches fishes from the highest trophic level, and muroami catches with highest rate per person per trip. According to most fishers, fishing operations strategies were highly influenced by weather conditions. The proportion of fishers that choose to adapt and exit the fishery in concomitant to the decline in catch was increased. The most common adaptation strategies used were reducing fishing effort, changing gears, and move to other fishing grounds. Assessing natural and human system dynamic is essential factors in managing reef fisheries with high consideration to the balance between ecological and socioeconomic factors.