Although researchers have investigated the impact of Indian Ocean Dipole (IOD) phases on human lives, only a few have examined such impacts on fisheries. In this study, we analyzed the influence of negative (positive) IOD phases on chlorophyll a (Chl-a) concentrations as an indicator of phytoplankton biomass and small pelagic fish production in the eastern Indian Ocean (EIO) off Java. We also conducted field surveys in the EIO off Palabuhanratu Bay at the peak (October) and the end (December) of the 2019 positive IOD phase. Our findings show that the Chl-a concentration had a strong and robust association with the 2016 (2019) negative (positive) IOD phases. The negative (positive) anomalous Chl-a concentration in the EIO off Java associated with the negative (positive) IOD phase induced strong downwelling (upwelling), leading to the preponderant decrease (increase) in small pelagic fish production in the EIO off Java.

Seagrass perform a variety of functions within ecosystems, and have both economic and ecological values, therefore it has to be kept sustainable. One of the stages to preserve seagrass ecosystems is monitoring by utilizing thespatial data accurately. The purpose of the study was to assess and compare the accuracy of DII and PCA transformationsfor mapping of seagrass ecosystems. Fieldstudy was carried out in Karang Bongkok and Kotok Island waters, in Agustus 2014 and in March 2015. A WorldView-2 image acquisition date of 5 October 2013 was used in the study. The transformations for image processing data were Depth Invariant Index (DII) and Principle Component Analysis (PCA) using Support Vector Machine (SVM) classification. The result shows that benthic habitat mapping of Karang Bongkok using DII and PCA transformations were 72%and 81% overall's accuracy respectively, whereas of Kotok Island were 83% and 84% overall's accuracy respectively. There were seven benthic habitat types found in karang Bongkok waters and in Kotok Island namely seagrass, sand, rubble, coral, logoon, sand mix seagrass, and sand mix rubble. PCA transformation was effectively to improve mapping accuracy of sea grass mapping in Kotok Island and Karang Bongkok.

Anzani L, Madduppa HH, Nurjaya IW, Dias PJ. 2019. Short Communication: Molecular identification of White Sea Squirt Didemnum sp. (Tunicata, Ascidiacea) colonies growing over corals in Raja Ampat Islands, Indonesia. Biodiversitas 20: 636-642. Indonesia is at the center of the Coral Triangle, the region with the world’s highest marine biodiversity. The Raja Ampat archipelago in east Indonesia has one of the oldest networks of marine protected areas in the country and is a top priority area for marine conservation. The area is however under anthropogenic pressure from growing tourism, developments and exploration of natural resources. The most likely associated introduction of non-native species is however largely unexplored. Colonial ascidians or ‘sea squirts’ comprise a high number of species, many of them reported as introduced or invasive worldwide. In this study, we investigate the presence of white colonial ascidian colonies noticed to overgrow sections of the coral reefs in central Raja Ampat. We use DNA barcoding to address the colonies’ species identification and explore haplotype diversity to determine the species native or introduced status. We produced 22 DNA barcodes belonging to four potential cryptic Didemnum sp. species present in the Raja Ampat archipelago, Indonesia. Overall, the high number of haplotypes found in the area suggest these to most likely to be native species. The present work represents, as far as the authors are aware, the first time that such species were investigated in Raja Ampat. We hope with this work to create awareness for the topic of introduced and invasive species in the area and motivate further studies in Indonesia.