Exploitation rate of the blue swimming crab (BSC) in Indonesian Fisheries Management Area (FMA) 712 is over-optimum level in 2016. Stocks concern in sustainable management is needed as an effort to maintain its availability. The objective of this study is to identify the stock unit of BSC based on Truss Network Analysis (TNA) of morphometric characters in FMA 712. The BSC was collect in five different locations, i.e. East Lampung, Lancang Island, Cirebon, Rembang, and Southern Madura. Measurements on TNA were carried out at 14 landmark points with 29 characters in carapace to analyze its morphometric characters. The cluster analysis showed that TNA method revealed two stocks units of BSC in FMA 712. The first stock was the BSC population of Southern Madura, and the other stock was the other four population. The longest Euclidean distance was found at Southern Madura indicating similarity level with other populations was low. The discriminant analysis demonstrated the different result. There were three group populations, which every population in one group were able to represent the other population, namely Lancang Island-Cirebon, East Lampung-Rembang, and Southern Madura. Regarding to this study, it is recommended to manage BSC in Southern Madura separately.

This study was conducted to analyze the changes in mangrove area and the density level of mangrove based on satellite imagery and field surveys in Untung Jawa Island. The image data used was Landsat image data acquired in 2000, 2005, 2010, 2015 and 2019. Apart from those, sentinel-2 data received in April 2019 were also retrieved to be compared with field data to see the density level and its accuracy. Image analysis to determine the area and density of mangroves was the Normalized Difference Vegetation Index (NDVI) model. Measurement of mangrove vegetation in the field was obtained by the line plot transect method. The results of temporal image data analysis showed the changes in mangrove area from 2000 (8.46 ha), 2005 (7.56 ha), 2010 (8.45 ha), 2015 (10.65 ha) and 2019 (6.89 ha). In 2019 the mangrove density was dense, while the result of the field survey was categorized as very dense. The level of accuracy for density using remote sensing data is 92.5%. Through the results of the field survey, the mangrove diversity was relatively low, mangrove species on the island was very uneven, and the dominant species was Rhizophora mucronata.

Abstrak Cytochrome b (cyt b) adalah salah satu gen pada DNA mitokondria yang sering digunakan sebagai marka molekuler untuk mengidentifikasi spesies melalui metode DNA barcoding. Penelitian ini bertujuan untuk menentukan karakteristik bioinformatika gen penyandi cyt b yang diisolasi dari ikan tenggiri (tenggiri papan dan tenggiri totol). Hasil amplifikasi PCR menunjukkan bahwa panjang DNA cyt b yang diisolasi dari ikan tenggiri papan 803 pasangan basa dengan komposisi purin 312 pasangan basa dan pirimidin 491 pasangan basa, sedangkan ikan tenggiri totol 791 pasangan basa dengan komposisi purin 316 pasangan basa dan pirimidin 475 pasangan basa. Analisis filogenetik menunjukkan bahwa kedua sampel termasuk kedalam kelompok Scomberomorus commerson dan Scomberomorus koreanus yang merupakan jenis ikan tenggiri. Titik isoelektrik cyt b ikan tenggiri papan 6,38 dan berat molekul 29826,23; ikan tenggiri totol 8,67 dan berat molekul 29372,77. Cyt b ikan tenggiri papan dan tenggiri totol memiliki kecenderungan hidrofobik. Dugaan pemodelan 3D cyt b pada kedua jenis ikan terdapat delapan bagian berbeda berdasarkan perbedaan warna yang ditampilkan. Kata kunci: karakteristik molekuler, cytochrome b, ikan tenggiri Abstract Cytochrome b (cyt b) is one of the genes in mitochondrial DNA that is often used as a molecular marker to identify species through DNA Barcoding. The aim of the present study was to investigate the bioinformatic of cyt b that isolated from mackerel fish. PCR amplification showed the length of DNA cyt b from king mackerel was 803 bp within purine 312 bp and pyrimidine 491 bp while Korean mackerel 791 bp within purine 316 bp and pyrimidine 475 bp. Phylogenetic analysis showed all sample join in mackerel groups (Scomberomorus commerson and Scomberomorus koreanus). The Isoelectric point value of cyt b from king mackerel is 6.38 and molecular weight is 29826.23; Korean mackerel are 8.67 and molecular weight is 29372.77. Hydrophaty plot showed cyt b of mackerel more hydrophobic. Based on 3D modelling both of them have eight different sections showing by different colors.

The management of fish stocks is essential for the maintenance of a healthy and profitable fishery. One of important knowledge regarding the matter is the stock structure of the target fish, and fish morphology can be used to determine the stock structure. In fishery point of view, Indonesian waters are divided into 11 Fisheries Management Area. This study was aimed to reveal the stock structure of the Indian mackerel (Rastrelliger kanagurta Cuvier, 1816) in Fisheries Management Area (FMA) 712. The fish collection was made in three different locations, i.e. Lancang Island, Cirebon, and Madura Island. Thirty-four morphological characters were measured to determine the stock structure with Truss Network Analysis (TNA). The results showed that both of conventional method and TNA revealed two stocks of Indian mackerel in the in FMA 712. The first stock was the fish population of Lancang Island and Cirebon, and the other was the population of Madura Island. The discriminant analysis also showed a similar result. For best future sustainable fishery management in Indonesian waters, more research on stock structure of any commercial fish in each fisheries management area of Indonesia is warranted.

Coral fish is one of the biota that live in coral reef ecosystems and its life is very dependent on thecondition of coral reefs. Pterocaesio chrysozona is a species of reef fish from the family Caesionidae that live in groups around coral reefs between 0-25 meters deep. Morphogenetic, morphological and DNA barcoding based measurements have advantages in identifying species that have been proven successful in identifying reef fish species. Morphometric and morphological analysis results showed that the overall specimens identified were Pterocasio chrysozona fish. It is directly proportional to the DNA Barcoding analysis which is read at the level of Pterocasio chrysozona fish species with a percentage of 93% Query Cover and Per. Ident 96.54%.