Analisis Morfometrik dan Klasifikasi Bentuk Lutjanus spp. Berdasarkan Gambar Digital

Lutjanus spp is a genus of the Lutjanidae family. The number of Lutjanus spp in waters around the world are 72 species. For this amount, 33 of them living on Indonesian waters. According to the IUCN List (2020), about ten species have decreased in population. One of the causes that population decline in several species is, the recording of capture fisheries has very limited production data. This is caused by the difficulty of identification in the field, which results in the overfishing of certain species. The identification process can be carried out based on morphometric features. Geometric morphometrics can be explaining morphological variations objectively and accurately. There are several methods used to represent the shape of an image in general. Namely point linking, complex coordinate, tangent angle, contour curvature, and triangle-area representation.Lutjanus spp by calculating the value of landmark positions, landmark curvature, changes in landmark angle, landmark distance, and landmark inclination. The results of feature extraction were used to classify Lutjanus spp (Lutjanus argentimaculatus, Lutjanus bohar, Lutjanus carponotatus, Lutjanus fulviflamma, and Lutjanus sebae). The results of this study indicate that the morphometric geometric approach can extract the feature values of the position of landmarks, a curvature of landmarks, changes in the angle of the landmark, distance of landmark, and the inclination of the landmark. The classification results using the Support Vector Machine (SVM) classification technique can distinguish Lutjanus spp with an accuracy rate of 65.03%. Thus, the application of SVM can be used to classify Lutjanus spp species, which will be useful in the identification process. Keywords: clasificasion, identification, morphometric geometric, Lutjanus spp, support vector machine. AbstrakLutjanus spp. adalah salah satu marga dari famili Lutjanidae. Jumlah spesies Lutjanus spp di perairan seluruh dunia yaitu 72 spesies. Dari 72 spesies tersebut 33 diantaranya hidup di perairan Indonesia. Menurut IUCN (2020) sekitar 10 spesies mengalami penurunan populasi. Salah satu penyebab menurunnya populasi pada beberapa spesies yaitu pencatatan data produksi perikanan tangkap masih sangat terbatas. Hal ini disebakan oleh sulitnya identifikasi di lapangan sehingga mengakibatkan overfishing pada spesies tertentu. Proses identifikasi dapat dilakukan berdasarkan ciri morphometrik. Geometri Morfometrik dapat menjelaskan variasi morfologi secara objektif dan akurat. Ada beberapa metode yang digunakan dalam merepresentasi bentuk suatu citra secara umum. yaitu point linking, complex coordinate, tangent angle, contour curvature, serta triangle-area representation. Pendekatan morphometric geometric pada penellitian ini digunakan untuk mengekstraksi fitur bentuk Lutjanus spp. dengan menghitung nilai posisi landmark, kelengkungan landmark, perubahan sudut landmark, jarak landmark, dan kemiringan landmark. Hasil ekstraksi fitur digunakan untuk mengklasifikasikan spesies Lutjanus spp. (Lutjanus argentimaculatus, Lutjanus bohar, Lutjanus carponotatus, Lutjanus fulviflamma, dan Lutjanus sebae). Hasil penelitian ini menunjukkan, bahwa pendekatan Geometri Morfometrik dapat melakukan ekstraksi nilai fitur posisi landmark, kelengkungan landmark, perubahan sudut landmark, jarak landmark, dan kemiringan landmark. Adapun hasil klasifikasi menggunakan teknik klasifikasi Support Vector Machine (SVM) mampu membedakan spesies Lutjanus spp. dengan tingkat akurasi sebesar 65.03%. Dengan demikian, penerapan SVM dapat digunakan untuk melakukan klasifikasi terhadap spesies Lutjanus spp yang akan bermanfaat pada proses identifikasi.Kata kuncis: klasifikasi, identifikasi, geometri morfometrik, spesies lutjanus spp., support vector machine.

Protection Efforts of Lutjanus bohar (The Two-Spot Red Snapper) Spawning Area in Hoga Island Waters, Kaledupa-Wakatobi National Park

A spawning area of Lutjanus bohar, a marine fish of high economic value, is one of the eight important resources of Wakatobi and also a critical habitat in the waters of Hoga Island. For protecting the area, Wakatobi National Park has stated the area as a tourism zone (no-take zone). This research was conducted to evaluate progress toward spawning-area protection by examine number of individuals, length size of fish, and trespassing cases that occurred in the spawning area. Research was carried out in 2018-2019. Number of individuals and size of fish were collected by referring to the monitoring guidelines for the Spawning Aggregation Site (SPAGs), and observations with an Underwater Visual Census. Trespassing case data were collected by interview key persons. Descriptive analysis was used to describe progress toward spawning-area protection. The results indicate that the protection effort of spawning area has a positive impact in increasing number of individuals and length of Lutjanus bohar. However, number of trespassing cases in the waters of Hoga Island still shows an increase. Fishing activities are the most trespassing cases occurred in the spawning area. This approach should be implemented to evaluate the progress towards protection efforts, besides increasing the number of patrols and socialization with fishermen to increase their awareness.

Identification of Causative Ciguatoxins in Red Snappers Lutjanus bohar Implicated in Ciguatera Fish Poisonings in Vietnam

Ciguatera fish poisoning (CFP) is a type of food poisoning caused by the consumption of a variety of toxic ciguatera fish species in the tropical and subtropical waters. Although there have been a large number of suspected CFP cases in the Southeast Asian countries, few were confirmed with causative ciguatoxins (CTXs), and reliable information on the symptoms still remains rather limited. In the present study, CTXs in red snapper Lutjanus bohar, implicated in two suspected CFP cases in Vietnam in 2014 and 2016, were determined by use of the single-quadrupole selected ion monitoring (SIM) liquid chromatography/mass spectrometry (LC/MS). Ciguatoxin-1B (CTX-1B), 54-deoxyCTX-1B, and 52-epi-54-deoxyCTX-1B were detected in the red snapper by our LC/MS method. Moreover, CTX-1B, 54-deoxyCTX-1B, and 52-epi-54-deoxyCTX-1B were further identified by the time of flight (TOF) LC/MS with the exact mass spectrum. The CTX profile of the red snapper in Vietnam is similar to those of ciguatera fish from Australia, Okinawa Islands in Japan, Kiribati, and Hong Kong. This is the first comprehensive report unambiguously identifying the causative toxins in fish implicated with reliable information on the poisoning symptoms in CFP in Vietnam and/or Southeast Asian countries.

Determination of Toxins Involved in Ciguatera Fish Poisoning in the Pacific by LC/MS

Ciguatera fish poisoning is the most extensive and difficult to control of the seafood poisonings. Tofacilitate monitoring of fish toxicity, toxin profiles were investigated by an LC/MS/MS method using 14reference toxins on eight representative species of fish collected in four different areas of the Pacific. Snappers and groupers from Okinawa contained ciguatoxin-1B (CTX1B) and two deoxy congeners at variablebut species-specific ratios, while red snapper, Lutjanus bohar, from Minamitorishima, and amberjack, Seriola dumerili, from Hawaii, contained both CTX1B-type and CTX3C-type toxins. Spotted knifejaw, Oplegnathus punctatus, from Okinawan waters, contained mainly CTX4A and CTX4B, but the same species caught at Miyazaki was contaminated primarily with the CTX3C-type toxins. Otherwise, the toxin profiles were consistently species-specific in fish collected from various locations around Okinawa over 20 years. The LC/MS/MSand mouse bioassay results agreed well, indicating the LC/MS/MS method is a promising alternative to themouse bioassay. Pure CTX1B and CTX3C were prepared for use in future LC/MS/MS analysis.

Species Identification of Ciguatoxin-Carrying Grouper Implicated in Food Poisoning

Food poisoning due to ingestion of an unknown red grouper occurred in southern Taiwan. To identify the species of toxic red grouper implicated in food poisoning, a 475-bp sequence of the cytochrome b gene from six species of fresh red grouper meat was amplified by using a pair of primers (L14735/H15149). This fragment could be amplified when fish meat was treated with different heating processes. After sequencing, it was found that no variation in sequences was detected among individuals within each species. The species of toxic red grouper meat implicated in food poisoning was judged to be Lutjanus bohar based on sequence analysis. In addition, restriction enzyme analysis with HaeIII rapidly distinguished these six species of red grouper and the two samples implicated in food poisoning. No toxicity of viscera in 18 specimens of six red grouper species was detected, but two food poisoning samples were found to be toxic. This study indicated that DNA sequence and restriction enzyme analysis are powerful methods for identifying potentially toxic red grouper species as L. bohar.