STRUKTUR UKURAN DAN TINGKAT PEMANFAATAN IKAN LENCAM (Lethrinus lentjan Lacepede, 1802) PERAIRAN ARAFURA DI PROBOLINGGO

AbstrakPenangkapan ikan di perairan Arafura banyak dilakukan oleh nelayan dari Pulau Jawa diantaranya Jakarta, Probolinggo, Pati, dan Indramayu. Nelayan dari Probolinggo yang menangkap ikan di perairan Arafura (WPP 718) menggunakan alat tangkap jaring dan pancing rawai dengan tujuan utama adalah ikan demersal, yaitu kakap (Lutjanus spp.), kerapu (Epeniphelus spp.), lencam (Lethrinus lentjan.), dan lainnya. Pemanfaatan ikan demersal terutama ikan lencam (Lethrinus lentjan) yang terus-menerus akan memicu terjadinya perubahan stok populasi ikan di perairan, sehingga diperlukan analisa ilmiah sebagai dasar pengelolaan perikanan. Tujuan dari analisa ilmiah ini untuk menjadi nilai kontrol dalam pengawasan jumlah eksploitasi ikan dan bahan pengkajian stok ikan lencam (Lethrinus lentjan). Penelitian dilakukan Februari hingga Desember 2017 di TPI Mayangan Probolinggo. Struktur ukuran ikan 23–65 cmFL dengan dominan pada ukuran 50 cmFL dengan ukuran pertama kali tertangkap (Lc) 44,5 cmFL. Laju pertumbuhan (K) 0,32 per tahun dengan panjang asimtotik 74 cmFL. Tingkat kematian karena penangkapan (F) lebih tinggi daripada tingkat kematian alami (M) dan tingkat eksploitasi E = 0,57%, yang berarti telah terjadi overfishing. Pengurangan eksploitasi sebesar 14%, dan penetapan ukuran layak tangkap serta ukuran legal diperdagangkan dapat menjadi upaya dalam dalam menjaga populasi ikan lencam.Abstract Fishing in Arafura waters is mostly done by fishermen from Java, including Jakarta, Probolinggo, Pati, and Indramayu. Fishermen from Probolinggo who catch fish in Arafura waters (FMA 718) use fishing nets and longline fishing with the main purpose being demersal fish, namely snapper (Lutjanus spp.), Groupers (Epeniphelus spp.), Lencam (Lethrinus lentjan) and others. Exploitation of demersal fish, especially lencam fish (Lethrinus lentjan) which will continually trigger changes in fish population stock in waters, so the scientific analysis is needed as a basis for fisheries management. The purpose of this scientific analysis is to become a control value in monitoring the amount of fish exploitation for fish stock assessment (Lethrinus lentjan). The study was conducted from February to December 2017 at TPI Mayangan Probolinggo. The size structure of fish 23–65 cmFL with a dominant size of 50 cmFL with the length at first capture (Lc) 44.5 cmFL. Growth rate (K) 0.32 per year with an asymptotic length of 74 cmFL. The fishing mortality (F) is higher than the natural mortality (M) and the exploitation level E = 0.57%, which means overfishing has occurred. The 14% reduction in exploitation and the determination of catch size and legal size of trade can be an effort in maintaining fish populations.

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BIOLOGICAL DIVERSITY ON THE BENINESE CONTINENTAL SHELF DURING THE DEMERSAL FISH STOCK ASSESSMENT SURVEY

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES FISHING INDUSTRY ◽

10.24143/2073-5529-2018-3-48-59 ◽

2018 ◽

pp. 48-59

Author(s):

Sohou Zacharie ◽

Okpeitcha O. Victor ◽

Sankare Yacouba

Keyword(s):

Biological Diversity ◽

Stock Assessment ◽

Demersal Fish ◽

Fish Population ◽

Species Number ◽

Fish Stock ◽

Survey Period ◽

Continental Shelves ◽

Assessment Survey ◽

Fish Stock Assessment

The global objectives of this study are to assess biodiversity composition in the tested trawling areas during the survey period. This study cannot take in account all species that can occur in the fishing areas because of the shortness of the work. To have a most complete list of species it will be better to carry out the survey covering four hydrologic periods (2 hot and 2 cold hydrologic periods) to have a chance to meet most of the species. However, the work was done during the most important period for the study. This study was conducted in terms of the demersal fish stock assessment survey initiated by the West African Economic and Monetary Union in the continental shelves of states members and neighboring countries (Côte d'Ivoire, Ghana, Togo and Benin) for the south part of Africa in order to determine fish population and abundance. In the waters of Benin, there have been listed 100 fish species including 76 demersal species (69 bony and 7 cartilaginous fish) and 13 pelagic species consisting entirely of bony specimens. Species richness, according to the reports of trawling stations, varies between 28 and 7 species. Fish abundance is the largest at the depth of 25-50 m. According to the data of station 10, species number makes 7.76% of the total, followed by station 19 with 26 taxa at the depth of 50-100 m. The lowest taxon number is registered in station 4 at a depth of 10-25 m with 4 taxa representing 1.94% of all targeted. The Simpson's index is close to 0, varying between 0 and 0.049, it shows a great diversity especially in the first stratum of 10 to 25 m. This study allows to evaluate species diversity in different fishing areas and consequences of the significant increase of fishing pressure on the stand and not only to focus on a few populations of species of commercial interest.

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High-Resolution Acoustic Cameras Provide Direct and Efficient Assessments of Large Demersal Fish Populations in Extremely Turbid Waters

Applied Sciences ◽

10.3390/app11041899 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1899

Author(s):

Céline Artero ◽

Simon Marchetti ◽

Eric Bauer ◽

Christophe Viala ◽

Claire Noël ◽

...

Keyword(s):

Spatial Distribution ◽

Fish Species ◽

Acoustic Signal ◽

Size Structure ◽

Demersal Fish ◽

Fish Population ◽

Spatial And Temporal Variation ◽

Fish Stock ◽

Actual Length ◽

Marine Habitats

Monitoring fish species populations in very turbid environments is challenging. Acoustic cameras allow work in very poor visibility but are often deployed as a fixed observation point, limiting the scope of the survey. A BlueView P900-130 acoustic camera was deployed in rocky marine habitats off the coast of French Guiana in order to assess the total abundance, size structure and spatial distribution of a demersal fish population. The relevancy of using an acoustic camera to achieve these three objectives was evaluated by comparing acoustic data to those obtained from fishing surveys. The detection and identification of large demersal fish species were possible with the shape and size of the acoustic signal and acoustic shadow silhouette as well as swimming behavior. Mobile surveys combined with stationary surveys increased the probability of distinguishing individuals from inanimate objects. Estimated total length based on the acoustic signal underestimated the actual length of fish measured on deck, but the data showed the same trends in spatial and temporal variation. Acoustic cameras overcame the extreme lack of visibility by increasing knowledge of fish use of habitat, therefore providing much more efficiency in the effort, more accurate data on the abundance, size structure and spatial distribution than the fishing method. Thus, despite few limitations, acoustic camera surveys are far superior to fishing surveys in evaluating large demersal fish stock status.

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Manual of Methods for Fish Stock Assessment. Part I. Fish Population Analysis.

Journal of Applied Ecology ◽

10.2307/2402904 ◽

1971 ◽

Vol 8 (2) ◽

pp. 616

Author(s):

B. B. Parrish ◽

J. A. Gullard

Keyword(s):

Stock Assessment ◽

Population Analysis ◽

Fish Population ◽

Fish Stock ◽

Fish Stock Assessment

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Data for Fish Stock Assessment Obtained from the CMSY Algorithm for all Global FAO Datasets

Data ◽

10.3390/data4020078 ◽

2019 ◽

Vol 4 (2) ◽

pp. 78 ◽

Cited By ~ 1

Author(s):

Arnaud Hélias

Keyword(s):

Stock Assessment ◽

Reference Points ◽

Fish Stock ◽

Fish Stocks ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Fish Catch ◽

The Absolute ◽

Fish Stock Assessment

Assessing the state of fish stocks requires the determination of descriptors. They correspond to the absolute and relative (to the carrying capacity of the habitat) fish biomasses in the ecosystem, and the absolute and relative (to the intrinsic growth rate of the population) fishing mortality resulting from catches. This allows, among other things, to compare the catch with the maximum sustainability yield. Some fish stocks are well described and monitored, but for many data-limited stocks, catch time series are remaining the only source of data. Recently, an algorithm (CMSY) has been proposed, allowing an estimation of stock assessment variables from catch and resilience. In this paper, we provide stock reference points for all global fisheries reported by Food and Agriculture Organization (FAO) major fishing area for almost 5000 fish stocks. These data come from the CMSY algorithm for 42% of the stock (75% of the global reported fish catch) and are estimated by aggregated values for the remaining 58%.

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Integrating Anisakis spp. parasites data and host genetic structure in the frame of a holistic approach for stock identification of selected Mediterranean Sea fish species

Parasitology ◽

10.1017/s0031182014001103 ◽

2014 ◽

Vol 142 (1) ◽

pp. 90-108 ◽

Cited By ~ 17

Author(s):

S. MATTIUCCI ◽

R. CIMMARUTA ◽

P. CIPRIANI ◽

P. ABAUNZA ◽

B. BELLISARIO ◽

...

Keyword(s):

Mediterranean Sea ◽

Stock Assessment ◽

Spatial Scales ◽

Holistic Approach ◽

Fish Population ◽

Fish Host ◽

Fish Stock ◽

Stock Identification ◽

Fish Stocks ◽

Fish Stock Assessment

SUMMARYThe unique environment of the Mediterranean Sea makes fish stock assessment a major challenge. Stock identification of Mediterranean fisheries has been based mostly from data on biology, morphometrics, artificial tags, otolith shape and fish genetics, with less effort on the use of parasites as biomarkers. Here we use some case studies comparing Mediterranean vs Atlantic fish stocks in a multidisciplinary framework. The generalized Procrustes Rotation (PR) was used to assess the association between host genetics and larval Anisakis spp. datasets on demersal (hake) and pelagic (horse mackerel, swordfish) species. When discordant results emerged, they were due to the different features of the data. While fish population genetics can detect changes over an evolutionary timescale, providing indications on the cohesive action of gene flow, parasites are more suitable biomarkers when considering fish stocks over smaller temporal and spatial scales, hence giving information of fish movements over their lifespan. Future studies on the phylogeographic analysis of parasites suitable as biomarkers, and that of their fish host, performed on the same genes, will represent a further tool to be included in multidisciplinary studies on fish stock structure.

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