THE CHANGES OF COASTAL ECOSYSTEM IN EAST SERAM DISTRICT, MALUKU PROVINCE, INDONESIA AND ITS IMPACT ON THE JULUNG-JULUNG FISH (Hemirhamphus sp) RESOURCES
Authors:   Research Centre for Oceanography, National Research and Innovation Agency, Jakarta/Centre for Colloborative Research on Aquatic Ecosystem in Eastern Indonesia, Ambon/Faculty of Mathematics and natural Sciences, University of Indonesia, Gedung Dakanat, Depok, PELASULA Daniel D. , WOUTHUYZEN Sam ,   Research Centre for Oceanography, National Research and Innovation Agency, Jakarta/Centre for Colloborative Research on Aquatic Ecosystem in Eastern Indonesia, Ambon, WAILERUNY Welem ,   Faculty of Fisheries and Marine Sciences, Pattimura University, Ambon, RUBAMLIFAR Adam ,   Department of Cooperatives and Small Business, East Seram Regency, HUKOM Frensly D. ,   Research Centre for Oceanography, National Research and Innovation Agency, Jakart/Centre for Colloborative Research on Aquatic Ecosystem in Eastern Indonesia, Ambon, MATUANKOTA Caleb ,   Research Centre for Deep Sea, National Research and Innovation Agency, Ambon
Published: April 2023

"The sub-district of East Seram (SBT) is the oldest district in the East Seram Regency, Maluku Province, Indonesia. Ninety percent of this area is covered by the sea with 3 unique tropical coastal ecosystems, namely mangroves, seagrass, and coral reefs. This high productivity ecosystem provides various goods and environmental services in fisheries, tourism, and other industries. One of them is coastal resources such as Julung julung fish (Half-beak, Hemirhamphus spp) that use this ecosystem for their primary habitat. Unfortunately, little is known about the interaction between Julung-julung and their habitat. This paper aims to assess the changes of the coastal ecosystem of the SBT and their impact on Julung-julung resources. Two satellite images of Landsat-7 ETM+ (2001) and Sentinel-2A (2018) were analyzed to monitor the condition changes of mangrove and seagrass. Six habitat classes of sea, land vegetation, mangrove, dense, medium, and sparse seagrass were classified using isocluster analysis, validated using ground truth data collected during intensive field survey, and then the areas of each habitat class were calculated. From the period of 2001 to 2018, the areas of mangrove and seagrass have decreased from 1401.5 to 1118.8 ha, and from 3183.8 to 2509.4 ha, respectively. The decrease of mangroves was due to mangrove cutting for firewood that use to smoke Julung-julung, one of the famous fish products from the SBT, while mining dead coral for building materials in seagrass beds decreased their areas. Interview with experienced SBT’s fishers in catching Julung-julung showed that the population of this fish has decreased by about 30-50% within 20 years, which was most likely due to the impact of their habitat degradation. In contrast, the decrease of Julung-julung stocks in other province was mostly due to overfishing. Thus, maintaining, conserving, and revitalizing the mangrove and seagrass ecosystems in the SBT as the important habitat for the early life history of Julungjulung is inevitable, as well as it is necessary to immediately conduct in-depth study on biological and population dynamics of this fish, whose data is still lacking, so that the Julungjulung stocks can manage sustainably."