Komposisi hasil tangkapan jaring insang dasar di perairan Desa Talise Tambun, Kecamatan Likupang Barat (Composition catches of bottom gillnet in Talise Tambun Waters of Likupang Barat District)

The bottom gill nets are the most common fishing gear in coastal areas, with different mesh sizes.The catch of bottom gill nets is generally dameral fish with different sizes and species. Scientific information about the difference of catch composition in the 3-inch and 4-inch mesh size of bottom gill nets is still poorly available. It is therefore necessary to study a composition of the catch on two bottom gill net mesh sizes of 3 inches and 4 inches, comparing the composition of the quantity and weight of the catch and identify the species of fish caught. This research was done in coastal waters of Talise Tambun village, Likupang Barat District of Minahasa Utara Regency for two weeks October 2017; following a descriptive method based on case studies. Two unit bottom gill nets were operated seven trips to data colected; and the data were analyzed by composition species analysis and weight composition.The results showed that the composition of the catch quantity of bottom gill net 3-inch 64 fish and 48 species dominated by Rengginan fish 21.88%, while the catching composition of 4-inch mesh size amounted to 91 fishes and 63 species dominated by Swangi as 14.29% . The weight catch composition of the 3-inch bottom gill net was dominated by sharks of 25.16% with a weight of 33.386 kg, while the 4-inch bottom gill net catch weights were dominated by snapper as 35.71% with a weight of 101,502 kg.The results of the analysis showed that the 3-inch mesh size of bottom gill net catch composition of both the quantity, the species and the catch weight was better than the 4-inch capture composition.Keywords: Bottom gillnet, weight, composition ABSTRAKJaring insang dasar adalah alat tangkap yang banyak ditemukan diwilayah pesisir, dengan ukuran mata jaring yang berbeda-beda.Hasil tangkapan jaring insang dasar umumnya ikan damersal dengan ukuran dan jenis yang berbeda.Informasi Ilmiahtentang perbedaan komposisi hasil tangkapan pada jaring insang dasar mata 3 inci dan 4 inci masih kurang tersedia.Untuk itu perlu suatu penelitian yang bertujuan mengetahui komposisi hasil tangkapan pada dua ukuran mata jaring insang dasar 3 inci dan 4 inci, membandingkan komposisi jumlah dan bobot hasil tangkapan dan mengidentifikasi jenis ikan yang tertangkap.Penelitian ini dilaksanakan di perairanDesa Talise Tambun Kecamatan Likupang Barat Kabupaten Minahasa Utara; selama 2 minggu, pada bulan Oktober 2017; dikerjakan dengan mengikuti metode deskriptif yang didasarkan pada studi kasus.Dua unit jaring insang dasar PA Multifilament dengan besar mata masing-masing 3 dan 4 inci dioperasikan selama 7 trip untuk mengumpulkan data; dan data dianalisis dengan analisis komposisi jenis dan komposisi bobot.Hasil penelitian menunjukkan bahwa komposisi jumlah tangkapan jaring insang dasar mata 3 inci sebanyak 64 ekor dan 48 jenis yang didominasi oleh ikan Rengginan sebesar 21.88%, sedangkan komposisi tangkapan jaring insang dasar 4 inci berjumlah 91 ekor dan 63 jenis yang didominasi oleh ikan Swangi sebanyak 14.29 %. Selanjutnya komposisi bobot tangkapan jaring insang dasar mata 3 inci didominasi oleh ikan Hiu sebesar 25.16 % dengan bobot 33,386 kg, sedangkan komposisi bobot tangkapan jaring insang dasar mata 4 inci didominasi oleh ikan kakap sebanyak 35.71% dengan bobot 101,502 kg. Hasil analisis menunjukkan bahwa komposisi tangkapan jaring insang dasar mata 3 inci baik jumlah, jenis maupun bobot tangkapan lebih baik dibandingkan dengan komposisi tangkapan jaring insang dasar mata 4 inci.Kata-kata Kunci: Jaring insang dasar, bobot, komposisi.

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Komposisi hasil tangkapan soma darape di perairan pantai Desa Bajo Kecamatan Tatapaan Kabupaten Minahasa Selatan

JURNAL ILMU DAN TEKNOLOGI PERIKANAN TANGKAP ◽

10.35800/jitpt.2.3.2016.11448 ◽

2016 ◽

Vol 2 (3) ◽

Author(s):

Jersey R. Cumentas ◽

Lefrand Manoppo ◽

Johnny Budiman

Keyword(s):

Coastal Waters ◽

Scylla Serrata ◽

Fishing Gear ◽

Scatophagus Argus ◽

Predominant Species ◽

Fish Resources ◽

Siganus Canaliculatus ◽

Gill Net ◽

Catch Composition ◽

Descriptive Method

ABSTRACT Soma darape is a traditional net fishing gear that still operated in Amurang Bay because of simple in construction, relatively inexpensive, and easy to operate using a small boat. The operation, however, sometimes is done in damaging ways to fish resources and the environment. Therefore, this research aims to study the species and composition of catches of soma darape, as well as assessing the legal size of catches. This research was done in coastal waters near mangrove of Bajo Village, Tatapaan District, South Minahasa Regency in June 2015; based on descriptive method. The catch consisted of 19 species, and the predominant species (≥ 20) were Scatophagus argus (42), Tylosurus crocodiles (33), Carangoides ferdau (27), Scylla serrata (26), Leiognathus smithursti (21) and Terapon jarbua (20). There were 6 species that have a legal size, namely Terapon jarbua (1), Scatophagus argus (18), Siganus canaliculatus (3), Lutjanus fulvus (5), Sillago analysts (16) and Scylla serrata (1). Of the total catch, only 17.89% was legal size and 82.11% was not legal size. Keywords: soma darape, gill net, catch composition, Amurang Bay ABSTRAK Soma darape merupakan alat tangkap jaring tradisional yang masih dioperasikan di Teluk Amurang karena konstruksinya sederhana, relatif murah dan mudah dioperasikan dengan perahu ukuran kecil. Tetapi kadang-kadang pengoperasiannya dilakukan dengan cara-cara yang bersifat merusak sumberdaya ikan dan lingkungan. Oleh karena itu penelitian ini dilakukan untuk mempelajari jenis dan komposisi hasil tangkapan soma darape; serta menilai ukuran legal hasil tangkapan. Penelitian ini dilakukan di perairan pantai dekat mangrove Desa Bajo, Kecamatan Tatapaan Kabupaten Minahasa Selatan pada bulan Juni 2015; yang didasarkan pada metode deskriptif. Hasil tangkapan terdiri dari 19 spesies, dan spesies yang dominan (≥ 20 ekor) secara berturut-turut adalah ikan Scatophagus argus (42 ekor), Tylosurus crocodiles (33 ekor), Carangoides ferdau (27 ekor), Scylla serrata (26 ekor), Leiognathus smithursti (21 ekor) dan Terapon jarbua (20 ekor). Hanya 6 spesies yang memiliki ukuran legal tangkap, yaitu Terapon Jarbua (1 ekor), Scatophagus argus (18 ekor), Siganus canaliculatus (3 ekor), Lutjanus fulvus (5 ekor), Sillago analis (16 ekor) dan Scylla serrata (1 ekor). Secara total hasil tangkapan, hanya 17,89% yang layak tangkap dan 82,11% tidak layak tangkap. Kata-kata kunci: soma darape, jaring insang, komposisi tangkapan, Teluk Amurang

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ANALISIS PENANGKAPAN IKAN KAKAP MERAH (Lutjanus spp.) DAN KERAPU (Epinephelus sp.) DI PERAIRAN BARRU, SULAWESI SELATAN

Jurnal Kebijakan Perikanan Indonesia ◽

10.15578/jkpi.2.2.2010.101-112 ◽

2017 ◽

Vol 2 (2) ◽

pp. 101

Author(s):

Bambang Sumiono ◽

Tri Ernawati ◽

Wedjatmiko Wedjatmiko

Keyword(s):

Growth Characteristic ◽

Mesh Size ◽

Catch Rate ◽

Survey Period ◽

Gill Nets ◽

South Sulawesi ◽

Gill Net ◽

Long Line ◽

Catch Composition ◽

Epinephelus Malabaricus

Perairan di sekitar Barru Sulawesi Selatan merupakan salah satu kawasan terumbu karang yang penting di Selat Makassar. Sebagian besar dari nelayannya melakukan penangkapan ikan dengan menggunakan rawai dasar dan jaring insang dasar. Analisis perikanan ikan kakap merah (Lutjanus spp.) dan kerapu (Epinephelus sp.) dilakukan pada bulan Agustus dan Oktober 2006 dengan penekanan pada deskripsi alat tangkap dan teknik penangkapannya, komposisi hasil tangkapan, dan beberapa aspek biologi ikan kakap merah dan kerapu. Penelitian ini dilakukan dengan cara mengikuti kegiatan nelayan yang menggunakan rawai dasar dan jaring insang dasar di sekitar terumbu karang dan pencatatan data dari pendaratan ikan utama. Untuk kelengkapan data dilakukan wawancara dengan nelayan dan pedagang pengumpul setempat. Hasil penelitian ini menunjukan daerah penyebaran ikan kakap merah dan kerapu terdapat di perairan Barru dan Pangkajene Kepulauan. Pada perairan yang relatif dangkal (<50 m) digunakan pancing ulur dengan satu atau dua mata pancing (nomor 6 atau 7). Jaring insang dasar digunakan di luar daerah karang, satu pis (tinting) mempunyai panjang 40 m dan dalam 5 m dengan ukuran mata jaring 4 inci. Satu unit jaring terdiri atas 60 pis. Di perairan yang lebih dalam (lebih dari 50) digunakan rawai dasar yang terdiri atas 600 mata pancing (nomor 7 atau 8). Lama trip penangkapan tiga hari. Diperoleh laju pancing pada rawai dasar berkisar 6-8% dan laju tangkap jaring insang dasar berkisar antara 40-60 kg/kapal/tiga hari. Komposisi hasil tangkapan didominansi (47,2%) oleh ikan kakap merah (famili Lutjanidae) yang terdiri atas jenis Lutjanus malabaricus, Lutjanus hyselopterus, Lutjanus sebae, Lutjanus vittus, dan Pinjalo pinjalo. Ikan kerapu (famili Serranidae) terdiri atas jenis Epinephelus areolatus, Epinephelus malabaricus, Epinephelus microdon, dan Plectropomus maculatus. Kecuali itu tertangkap juga ikan lencam (famili Lethrinidae). Pengamatan biologi jenis ikan Lutjanus malabaricus dan Epinephelus malabaricus yang merupakan hasil tangkapan dominan masing-masing diperoleh nilai modus panjang cagak 48 dan 56 cm dengan modus bobot masing-masing 1,8 dan 2,15 kg. Karakteristik pertumbuhan kedua jenis tersebut adalah allometrik positif.The sea waters around Barru, South Sulawesi is one of the coral reef parts in Makassar Strait. Most of the fishermen use fishing lines, bottom long lines, and bottom gill nets in their fishing activities. Analysis of red snappers (Lutjanus spp.) and groupers (Epinephelus sp.) fisheries in this area were carried out in August and October, 2006. The emphasis is focused on the discription of fishing gear and fishing technique, catch composition, and some of biological aspect of red snappers and groupers. The research was done by following the fishing operations of bottom long line and bottom gill net conducted by fishers in the waters around coral reefs. Data were recorded in some importantant landing place at Barru, and interview of some fishermen to complete data and information needed. The result showed that the distribution of red snapper and groupers occured in the waters around Barru and Pangkajene Islands. In the shallow waters (<50 m) the fishermen use a lightly weighted hand line, with one or two relativelly small hooks (nomor 6 or 7). Bottom gill nets are frequently used in shallow back reef areas with one piece of 40 m in length, and 5 m in depth, with mesh size of 4 inches. One unit of the gear consisted of 60 piece of the nets. Meanwhile, in deeper waters (50-150 m), the number of hooks (nomor 7 or 8) in bottom long line operated 600 hooks for each unit. All fishing gears usually have three days at sea for a fishing trip. The average of catch rate (hook rate) for a trip of bottom long line was 6-8% (6 or 8 individual fish for 100 hooks). Meanwhile, the catch rate of bottom jaring insang was about 40-60 kgs/boat/3 days trip. The catches were dominated by the family Lutjanidae in which the red snappers species (reached to 47.2% at this survey period) including Lutjanus malabaricus, Lutjanus hyselopterus, Lutjanus sebae, Lutjanus vittus, and Pinjalo pinjalo. Meanwhile the groupers (family Serranidae) were dominated by species of Epinephelus areolatus, Epinephelus malabaricus, Epinephelus microdon, and Plectropomus maculatus. Other groups were emperors (Lethrinidae) and Gymnocranius. The biological measured for Lutjanus malabaricus and Epinephelus malabaricus as a dominant landed showed the modus of length were 48 and 58 cmFL, respectivelly. Meanwhile the modus of weight were 1.8 and 2.35 kg. The growth characteristic of both species were positive allometric. It means that increasing the weight was faster than their length.

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Komposisi hasil tangkapan jaring insang dasar dan cara tertangkapnya ikan di Perairan Malalayang (Composition catches of bottom gillnet and how to catch fish in Malalayang Waters)

JURNAL ILMU DAN TEKNOLOGI PERIKANAN TANGKAP ◽

10.35800/jitpt.3.2.2018.21427 ◽

2018 ◽

Vol 3 (2) ◽

Author(s):

Maikel F. Pondaag ◽

Meta S. Sompie ◽

Johnny Budiman

Keyword(s):

Mesh Size ◽

Fishing Ground ◽

Fish Swimming ◽

Gill Net ◽

Size Number ◽

Study Results ◽

Catch Composition ◽

Individual Size ◽

Descriptive Method

Gill net is a fishing gear set vertically underwater to ambushed off the fish swimming direction. The fish are caught by means of gill trapped or body entangled. One of the gill fishing ground is in Malalayang Dua, Manado. This study was aims to knowing the species composition of bottom gill net with mesh size of 3 inches, 3½ inches, and 4 inches, comparing the catch number and individual size caught in different mesh size, and knowing how they were caught. The study used a descriptive method based on a case study. Results showed that the catches were dominted by parrotfish (Scarus sp.), 26 individuals, followed by surgeonfish (Achanthurus pyroferus), 21 individuals, butterflyfish (Zanclus cornutus), 8 individuals, and other species, less than 5 individuals. The fish caught in the mesh size of 3 inches were 60 individuals, 3½ inches were 29 individuals, 4 inches were 2 individuals. The parrotfish were dominantly caught in the mesh size of 3 inches, 17 individuals, tangs in 3 inches, 13 individuals, and the butterflyfish in 3 inches, 7 individuals. The heaviest fish caught in the mesh size of 3½ inches was 2.74 kg for parrotfish, 1.55 kg for surgeonfish and 5.1 kg for goatfish.Keywords: bottom gill net, catch composition, size, number of catches. AbstrakJaring insang adalah jaring yang dipasang tegak lurus dalam air untuk menghadang arah renang ikan. Jaring insang dasar merupakan salah satu alat tangkap yang pengoperasiannya digemari oleh nelayan-nelayan yang dilakukan didaerah tertentu (certain area) tangkapan sehingga diharapkan semua ikan ataupun yang berada pada area dapat tertangkap. Salah satu daerah penangkapan ikan dengan jaring insang adalah Malalayang Dua Kota Manado. Penelitian ini bertujuan untuk mengetahui komposisi hasil tangkapan jaring insang dasar yang berukuran mata 3 inci, 3½ inci dan 4 inci, membandingkan komposisi jumlah dan ukuran hasil tangkapan dari ukuran mata jaring yang digunakan, dan mengetahui bagaimana cara tertangkapnya ikan pada berbagai ukuran mata jaring. Jenis ikan kakatua (Scarus sp) mendominasi hasil tangkapan sebanyak 26 ekor, diikuti oleh ikan butana (Achanthurus pyroferus) sebanyak 21 ekor, ikan kupu-kupu (Zanclus cornutus) sebanyak 8 ekor sedangkan jenis lainnya tertangkap kurang dari 5 ekor. Jumlah hasil tangkapan yang diperoleh ukuran mata 3 inci 60 ekor,ukuran mata 3½ inci yaitu 29 ekor, dan ukuran mata 4 inci hanya 2 ekor. Komposisi jumlah hasil tangkapan ikan Kakatua didominasi oleh mata jaring ukuran 3 inci yaitu 17 ekor, pada ikan Butana didominasi oleh mata jaring 3 inci yaitu 13 ekor, dan untuk ikan kupu-kuu didominasi oleh mata jaring 3 inci dengan jumlah 7 ekor. Bobot ikan kakatua lebih berat pada mata jaring 3½ inci yaitu 2,74 kg, ikan Butana lebih berat pada mata jaring 3½ inci yaitu 1,55 kg, dan ikan Biji nangka pada mata 3½ inci dengan berat 5,1 kg.Kata kunci : jaring insang dasar, komposisi hasil tangkapan, ukuran, hasil tangkapan

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Ketaatan Kapal Penangkap Jaring Insang di Laut Arafura yang Berpangkalan di Pelabuhan Perikanan Samudera Bitung (The obedience gill nets boats in the Arafura Sea that based in Bitung Oceanic Fisheries Port)

JURNAL ILMU DAN TEKNOLOGI PERIKANAN TANGKAP ◽

10.35800/jitpt.2.4.2016.14034 ◽

2017 ◽

Vol 2 (4) ◽

Author(s):

Bahrul Y. N. I. Syah ◽

Lefrand Manoppo ◽

Emil Reppie

Keyword(s):

Fishing Ground ◽

Gill Nets ◽

Fisheries Resources ◽

Gill Net ◽

Arafura Sea ◽

Descriptive Method

Arafura Sea waters are one of the good fishing ground for gill net boats over than 30 GT.Currently, there are 14 gill nets boats that fishing in these waters and are based in Bitung Oceanic Fisheries Port.Therefore, it is necessary to study the boat obedience-based during fishing activities. This study aimed to evaluate compliance gill net vessels based in Bitung Oceanic Port according long days operation in each trip and port based. This research was conducted from August to September 2015 in Marine and Fisheries Resources Supervision Base and Bitung Oceanic Fisheries Port; and done with descriptive method. Results of the analysis showed that 79% of gill net boats based in Bitung Oceanic Fisheries Port disobedient in day fishing operations; and 14% of the boats did not obey the appropriate port based.Key words: Gill net, Arafura Sea, obedience day operations, obedience-port based ABSTRAKPerairan Laut Arafura merupakan salah satu fishing ground yang cocok untuk pengoperasian jaring insang dengan kapal berukuran di atas 30 GT. Saat ini terdapat 14 kapal jaring insang yang menangkap ikan di perairan tersebut dan berpangkalan di Pelabuhan Perikanan Samudera Bitung. Oleh karena itu, perlu di lakukan kajian mengenai ketaatan berpangkalan kapal–kapal tersebut saat melakukan kegiatan perikanan. Penelitian ini bertujuan untuk mengevaluasi ketaatan kapal jaring insang yang berpangkalan di Pelabuhan Perikanan Samudera Bitung berdasarkan lama hari operasi dalam setiap trip dan pelabuhan pangkalan. Penelitian ini dilakukan pada bulan Agustus sampai September 2015 di Pangkalan Pengawasan Sumberdaya Kelautan dan Perikanan Bitung dan Pelabuhan Perikanan Samudera Bitung; dikerjakan dengan metode deskriptif. Hasil analisis menunjukan bahwa 79% kapal jaring insang yang berpangkalan di Pelabuhan Perikanan Samudera Bitung tidak taat menurut hari operasi penangkapan; dan 14% kapal tidak taat sesuai pelabuhan pangkalan. Kata kunci: Jaring insang, Laut Arafura, ketaatan hari operasi, ketaatan berpangkalan

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Catching Technology of Fish Maw Snapper’s: Case Study of the KMN Nur Aqila07 Fishing Boat in Kumbe Village, Malind District, Merauke Regency, Papua

E3S Web of Conferences ◽

10.1051/e3sconf/202132808011 ◽

2021 ◽

Vol 328 ◽

pp. 08011

Author(s):

Sajriawati Sajriawati

Keyword(s):

Data Collection ◽

Mesh Size ◽

Fishing Gear ◽

The Sun ◽

Running Water ◽

Gill Nets ◽

Weight Range ◽

Fishing Boat ◽

Gill Net

The purpose of this study was to determine the fishing technology used by fishermen in Merauke to catch snapper and post-harvest handling of fish maw snapper. This research was conducted in January 2021 in Kumbe Village, Malind District. Data collection was carried out by interviewing fishermen on the fishing boat KMN Nur Aqila07. The results showed that the fishing boat KMN Nur Aqila07 has a weight specification of 30 GT. The main fishing gear is a drift gill net with a length of 50 meters with a width of 2 meters with a mesh size of 7.5 inches. The pulley machine is used to help pull the gill nets when they want to pull fishing gear (hauling). Fish maw of snapper is removed manually using a knife, then cleaned with running water and then dried in the sun to dry. Fish maw is sold dry. The highest price for fish maw is in the weight range of 150 grams which can reach Rp. 22,500,000 per kg, while the lowest price is in the weight range of less than 50 grams, which is Rp. 4,500,000 per kg.

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Fish species composition and size structure exploited by gill net fishery in The New Calabar River, Nigeria

Acta Aquatica Aquatic Sciences Journal ◽

10.29103/aa.v6i1.1257 ◽

2019 ◽

Vol 6 (1) ◽

pp. 1

Author(s):

Olaniyi Alaba Olopade ◽

Henry Eyina Dienye ◽

Ogheneforon Oderhohwo

Keyword(s):

Species Composition ◽

Fish Species ◽

Size Structure ◽

Mesh Size ◽

Maximum Size ◽

Abundant Species ◽

Fish Stock ◽

Size Selectivity ◽

Gill Nets ◽

Gill Net

The purpose of this study was to investigate the species composition and size selectivity of gillnets commonly used by the artisanal fishers in the New Calabar River, Rivers State, Nigeria. The data was collected during February-July 2018 from 3 sampling stations: SI Choba, S2 Ogbogoro, and S3 Iwofe all along the stretch of the river. Twenty-eight fish species were found belonging to 15 families. The prevalent families were Cichlidae, Mugilidae and Clupeidae representing 32.22%, 30.36% and 10.23% of the total catch, respectively. The most dominant species in terms of number were Liza falcipinnis (12.58%) and Mugil cephalous (12.26%) while in terms of biomass, the most abundance species were Xenomystus nigri (24.12%) and Lutjanus agennes (12.50 %). The girth and total lengths of the fishes ranged from 5.20±0.20 to 21.00±0.00 cm and 8.85±0.15 to 28.19±1.13 cm respectively. The length at first capture (L50%) for the most abundant species (Liza falcipinnis) was calculated to be 14.13 cm while that of L25% and L75% were 12.70cm and 15.25cm respectively. It was concluded that the gill nets used in the New Calabar River exploit fish species of small sizes and few medium sized specimens relative to species potential maximum size. It is therefore recommended that for an improved and sustainable exploitation fish stock of the New Calabar River, the use of gillnets of less than 25 mm-mesh sizes and “other gears” should be prohibited.Keywords: gill nets; species composition; mesh size; selectivity; New Calabar River

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Satellite tagging highlights the importance of productive Mozambican coastal waters to the ecology and conservation of whale sharks

10.7287/peerj.preprints.3029v2 ◽

2017 ◽

Author(s):

Christoph A Rohner ◽

Anthony J Richardson ◽

Fabrice R A Jaine ◽

Michael B Bennett ◽

Scarla J Weeks ◽

...

Keyword(s):

Coastal Waters ◽

Habitat Preferences ◽

Habitat Choice ◽

Aerial Survey ◽

Whale Shark ◽

Coastal Habitat ◽

Long Distance ◽

Gill Nets ◽

Gill Net ◽

Whale Sharks

The whale shark Rhincodon typus is an endangered, highly migratory species with a wide, albeit patchy, distribution through tropical oceans. Ten aerial survey flights along the southern Mozambican coast, conducted between 2004–2008, documented a relatively high density of whale sharks along a ~200 km stretch of the Inhambane Province, with a pronounced hotspot adjacent to Praia do Tofo. To examine the residency and movement of whale sharks in coastal areas around Praia do Tofo, where they may be more susceptible to gill net entanglement, we tagged 15 juveniles with SPOT5 satellite tags and tracked them for 2–88 days (mean = 27 days) as they dispersed from this area. Sharks travelled between 10 and 2,737 km (mean = 738 km) at a mean horizontal speed of 28 ± 17.1 SD km day-1. While several individuals left shelf waters and travelled across international boundaries, most sharks stayed in Mozambican coastal waters over the tracking period. We tested for whale shark habitat preferences, using sea surface temperature, chlorophyll-a concentration and water depth as variables, by computing 100 random model tracks for each real shark based on their empirical movement characteristics. Whale sharks spent significantly more time in cooler, shallower water with higher chlorophyll-a concentrations than model sharks, suggesting that feeding in productive coastal waters is an important driver of their movements. To investigate what this coastal habitat choice means for their conservation in Mozambique, we mapped gill nets during two dedicated aerial surveys along the Inhambane coast and counted gill nets in 1,323 boat-based surveys near Praia do Tofo. Our results show that, while whale sharks are capable of long-distance oceanic movements, they can spend a disproportionate amount of time in specific areas, such as along the southern Mozambique coast. The increasing use of large-mesh gill nets in this coastal hotspot for whale sharks is likely to be a threat to regional populations of this iconic species.

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PENERAPAN PERUBAHAN UKURAN MATA JARING DALAM PENANGKAPAN IKAN TERBANG SECARA BERKELANJUTAN DI KECAMATAN SENDANA KABUPATEN MAJENE

JOURNAL OF INDONESIAN TROPICAL FISHERIES (JOINT-FISH) : Jurnal Akuakultur, Teknologi Dan Manajemen Perikanan Tangkap, Ilmu Kelautan ◽

10.33096/joint-fish.v1i1.16 ◽

2018 ◽

Vol 1 (1) ◽

pp. 17-27

Author(s):

Najamuddin Najamuddin ◽

Andi Assir ◽

Mahfud Palo ◽

Andi Asni Najamuddin

Keyword(s):

Mesh Size ◽

Community Empowerment ◽

Fishing Gear ◽

Young Fish ◽

Gill Nets ◽

Group Management ◽

Gill Net ◽

Large Numbers ◽

Flying Fish ◽

The Government

Catching flying fish in Sendana Majene Subdistrict is carried out continuously with gill nets 1-1.5 inches. The catch of flying fish is mostly still young fish (not yet worth catching). The demand for flying fish is quite high due to the existence of special stalls of smoke fly fish around fishing settlements. Apart from smoke flying fish, dried flying fish are also sold as souvenirs. Therefore, fishermen will continue to increase production. Various results of research and field observations show that gill net is able to catch flying fish well but the size of fish caught is dominated by young fish. The effort to increase the net mesh size to 1.5 inches resulted in the diminishing number of young flying fish. Catching flying fish in Majene waters is generally carried out with drifting gill nets with mesh sizes of 1 and 1.25 inches which are very intensive every fishing season while L50 (11.92 cm) and Lm (13.59 cm) for 1 inch more net mesh size were smaller compared to the length of the first gonad maturity, in this case most of the catch is still classified as young fish (Palo, 2009). Partners are a group of flying fish fishermen. Partner problems, flying fish production is getting smaller, group capacity is not strong and group management is still weak. Partners have not been able to obtain assistance facilities from various community empowerment programs carried out by the government. The approach to be used in this service includes: identification, observation, counseling, demonstration, construction, application, assistance, field observation and evaluation monitoring. Indicators of the success of activities are measured based on the results of the application of technology compared to the results of fishing gear commonly used by fishermen. Implementation of service includes counseling, construction of fishing gear, fishing operations and assistance has been going well. The size of 1.5-inch mesh is only able to catch flying fish in a limited amount, while the size of the 1.25-inch mesh can catch flying fish in relatively large numbers. Flying fish caught with 1.25-inch mesh size has passed the size of the first gonad mature so that it supports sustainable fisheries.

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Satellite tagging highlights the importance of productive Mozambican coastal waters to the ecology and conservation of whale sharks

10.7287/peerj.preprints.3029 ◽

2017 ◽

Author(s):

Christoph A Rohner ◽

Anthony J Richardson ◽

Fabrice R A Jaine ◽

Michael B Bennett ◽

Scarla J Weeks ◽

...

Keyword(s):

Coastal Waters ◽

Habitat Preferences ◽

Habitat Choice ◽

Aerial Survey ◽

Whale Shark ◽

Coastal Habitat ◽

Long Distance ◽

Gill Nets ◽

Gill Net ◽

Whale Sharks

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Satellite tagging highlights the importance of productive Mozambican coastal waters to the ecology and conservation of whale sharks

PeerJ ◽

10.7717/peerj.4161 ◽

2018 ◽

Vol 6 ◽

pp. e4161 ◽

Cited By ~ 17

Author(s):

Christoph A. Rohner ◽

Anthony J. Richardson ◽

Fabrice R. A. Jaine ◽

Michael B. Bennett ◽

Scarla J. Weeks ◽

...

Keyword(s):

Coastal Waters ◽

Habitat Preferences ◽

Habitat Choice ◽

Aerial Survey ◽

Whale Shark ◽

Coastal Habitat ◽

Long Distance ◽

Gill Nets ◽

Gill Net ◽

Whale Sharks

The whale sharkRhincodon typusis an endangered, highly migratory species with a wide, albeit patchy, distribution through tropical oceans. Ten aerial survey flights along the southern Mozambican coast, conducted between 2004–2008, documented a relatively high density of whale sharks along a 200 km stretch of the Inhambane Province, with a pronounced hotspot adjacent to Praia do Tofo. To examine the residency and movement of whale sharks in coastal areas around Praia do Tofo, where they may be more susceptible to gill net entanglement, we tagged 15 juveniles with SPOT5 satellite tags and tracked them for 2–88 days (mean = 27 days) as they dispersed from this area. Sharks travelled between 10 and 2,737 km (mean = 738 km) at a mean horizontal speed of 28 ± 17.1 SD km day−1. While several individuals left shelf waters and travelled across international boundaries, most sharks stayed in Mozambican coastal waters over the tracking period. We tested for whale shark habitat preferences, using sea surface temperature, chlorophyll-aconcentration and water depth as variables, by computing 100 random model tracks for each real shark based on their empirical movement characteristics. Whale sharks spent significantly more time in cooler, shallower water with higher chlorophyll-aconcentrations than model sharks, suggesting that feeding in productive coastal waters is an important driver of their movements. To investigate what this coastal habitat choice means for their conservation in Mozambique, we mapped gill nets during two dedicated aerial surveys along the Inhambane coast and counted gill nets in 1,323 boat-based surveys near Praia do Tofo. Our results show that, while whale sharks are capable of long-distance oceanic movements, they can spend a disproportionate amount of time in specific areas, such as along the southern Mozambique coast. The increasing use of drifting gill nets in this coastal hotspot for whale sharks is likely to be a threat to regional populations of this iconic species.

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