Bycatch assessment for fusilier gillnet to support ecosystem approach fisheries management (original) (raw)
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STUDY BACKGROUND: Fish production is best quantified as a change in biomass through time (integrating both the number and mass of individuals) reflected in components namely births (typically via recruitment of planktonic dispersed larvae), immigration, growth, death, and emigration (Carr & Hixon 1997). An adverse change in these components could affect fisheries productivity, although the effect will depend on which components are involved, their interaction, the magnitude and scale of the change caused by a proposed habitat-changing activity (Randall et al. 2013). Lee et al. (2005) reported that the 2004 shadow tsunami wave that hit Pulau Anak Datai did not cause major structural damage to the 8000 years old coral reefs, showing 51% hard coral cover and 1% soft coral coverage, nor did it drastically alter the physical water parameters post-tsunami, as compared to a study back in 1994 by Chou, which showed good levels of live coral cover (50-53%) at Pulau Anak Datai according to the health scale of the ASEAN-Australian Living Coastal Resources project. However, there is insufficient data to conclude that the coral reef fish population was affected by the recent Tsunami. Lee et al. (2005) also found that the number of coral reef fish species and individuals at Pulau Anak Datai was relatively low compared to other sites in Peninsular Malaysia, using the same sampling protocol, which may be due to the health of the coral reefs or levels of fishing. Projects that affect fish habitat can be divided into three types, namely 1) projects that reduce habitat quantity and carrying capacity; 2) projects that affect habitat quality and fish vital rates (i.e. stress, mortality) and 3) projects with impacts on scales large enough to result in ecosystem transformation (DFO 2013) On 2nd December 2014, Lafarge Malaysia Berhad (Kedah Cement Factory) and The Andaman Resort, Langkawi has worked on the deployment of 52 Artificial Reef Modules (ARMS) at northern part of Teluk Datai, located around 25-30 meters from The Andaman Resort’s Langkawi shoreline, with a maturation period of 10 years. The biological objectives of artificial habitat development are meant to meet these effects; 1) attraction effects – the recruitment and concentration of species from an existing stock, 2) productivity effects – an increase in the number and density of habitat-limited fish species due to greater food resources, reproductive habitat and/or protection from predators and 3) diversity effects – the attraction or development of new species in particular areas (Milon 1989). In this study, I will be focusing on the productivity aspect in relation to artificial reef deployment, which relies on the assumption that they provide additional critical habitat that increases the environmental carrying capacity and thereby the abundance and biomass of reef biota (Polovina 1994 & Bortone et al. 1994). Thus, the objectives of this study are; 1. to assess potential productivity of fish resources based on adult fish and larvae survey within surrounding natural reefs and Artificial Reef Modules of Teluk Datai and; 2. to determine the seasonal changes of fish larvae and adult fish community. ¬ ¬¬¬¬
2017
The trend of the fishing activity for the coral fish has increased annually in Wakatobi Island. Yet, data concerning the coral fish species are lacking. The data were needed to support management of the coral fisheries in Wakatobi waters. One of the methods to understand the status of coral fish stock in the poor data condition is by using the Spawning Potential Ratio (SPR) and Productivity and Susceptibility Analysis (PSA). PSA is a fish stock assesement method which allows all units within any of ecological components to be efectively and comprehensively screened for risk to human impact. The result of the research showed that thumbprint emperor (Lethrinus harak), humpback red snapper (Lutjanus gibbus), highfin coralgrouper (Plectropomus oligacanthus) and squaretail coralgrouper (Plectropomus areolatus) were heavily exploited. There should be regulations in the size of fish caught, the number of fishing fleet and the implementation of marine conservation in order to increase the e...
Jurnal Saintek Perikanan, 2011
Populasi ikan ekor kuning (Caesio cuning) di perairan Kepulauan Seribu telah mengalami penurunan. Penyebab utama menurunnya kelimpahan ikan Caesio cuning adalah karena terjadi kerusakan ekosistem terumbu karang yang merupakan habitat hidupnya. Penelitian ini bertujuan untuk mengkaji keterkaitan sumber daya ikan Caesio cuning dengan karakteristik habitat. Penelitian ini dilaksanakan di Kabupaten Kepulauan Seribu pada Bulan Mei 2009. Pengamatan tutupan substrat bentik, lifeform dan jumlah genus karang menggunakan metode transek kuadrat, sedangkan untuk melihat kelimpahan sumberdaya ikan Caesio cuning menggunakan Underwater Visual Cencus. Tutupan substrat bentik didominasi oleh tutupan abiotik dengan nilai rata-rata 36,42%, rata-rata tutupan karang keras sebesar 32,27% (kondisi sedang) didominasi oleh coral foliose, coral massive, acropora branching dan coral encrusting. Rata-rata kelimpahan ikan Caesio cuning sebesar 67 individu/250 m 2 . Utara Pulau Pramuka, Barat Pulau Panggang, dan Selatan Pulau Panggang hanya dijumpai ikan-ikan kecil. Usulan pengelolaannya disamping melakukan penutupan, perlu dilakukan introducing induk. Sebaliknya Timur Pulau Pramuka dan Timur Pulau Kayu Angin hanya ditemui ikan-ikan besar. Usulan pengelolaan disamping melakukan penutupan, perlu diikuti dengan introducing juvenile ikan. Pada bagian Barat Pulau Kayu Angin dapat dilakukan penutupan untuk memberikan kesempatan juvenile untuk tumbuh dan ikan dewasa untuk memijah. Bagian Selatan Pulau Belanda memiliki seluruh selang ukuran dan juga penutupan karang yang bagus. Kawasan ini dapat dijadikan Daerah Perlindungan laut dan pengembangan ekowisata yang ramah lingkungan.
IOP Conference Series: Earth and Environmental Science , 2019
This study aimed to fill the gap of knowledge on this group of fishes by estimating the natural stock, species composition and biodiversity of target reef fishes from three regencies; Alor, East Flores (Flores Timur) and Southwest Maluku (Maluku Barat Daya/MBD) using underwater visual census method. A total of 176 species belong to 19 families of economically important target fish were recorded from 62 survey sites. The highest estimated stock is located in Southwest Maluku Regency-based on both abundance and biomass values, followed by Alor Regency and the lowest in East Flores Regency. Target fish species from the family of Caesionidae has the highest composition both based on abundance (74%) and biomass (40%). The highest species composition of target fish is from Pterocaesio tile (57.65%) which is more than 50% of the overall target fish. Community structure of target fish in the three regencies is still in a relatively good condition based on diversity index (H'), evenness (E) and no domination (C) of a single species occurs inside the target fish community, with exception in Alor Regency where the community of target fish is indicated to be under pressure. Biodiversity index by Bray-Curtis analysis in each location shows that most of the sites have the similarity of 67.51%, suggesting that there is not much difference in terms of target fish community structure between the three regencies.
IOP Conference Series: Earth and Environmental Science, 2018
Located in the Indonesian fisheries management area (WPP) 714, the Banda Sea has a high potential of fisheries resources. However, information about reef fish resources is limited. This study aims to assess the Banda Sea reef fish diversity, abundance, and stocks. The diversity, abundance, and density of three reef fish groups (indicator, target, and major) were assessed using underwater visual census (UVC) from 287 sites. A stock assessment was done by multiplying fish habitat areas and fish density. There were 287, 42, and 301 species of target, indicator, and major groups recorded respectively. High abundances were found in Banda Islands and the Southeast region, while the lowest abundance was in the Kendari waters. The average density of indicator and major groups were 0.251 and 4.519 individuals.m-2 , with estimated stocks of 2,883×10 6 and 51,899 ×10 6 individuals (ind.) respectively. The density of target group fish which has economic values was 1.976 ind.m-2 , equivalent to the biomass of 599.6 ton.km-2 with stocks of 4,214,468 tons. Despite huge reef fish resources supporting the local livelihood, the stock tended to decrease in 2009-2012 and 2015-2016 in Flores and Banda Islands. Therefore, conservation and sustainable use of reef fishes of the Banda Sea is required.
The Ecosystem Approach to Fisheries (EAF) is a holistic one as EAF considers all species as important elements within the ecosystem. An EAF requires that community and ecosystem structure should be maintained by harvesting fish communities in proportion to their natural productivity, thereby sustaining the balance of species and sizes in a community. This article draws from research on the reef fish community and catch in Kotania Bay on Seram Island in Maluku, Indonesia, an area of approximately 6000 ha. Based on the trophic guild (ie the aggregation of species utilizing similar food resources) on the reef, the biomass of predator fish currently being captured now represents 40.4% of the total catch biomass. Members of the grouper family, the humphead wrasse (Cheilinus undulatus) and trevally (Caranx melampygus) in particular, have become targeted for sale in fish markets. If these predators are selectively targeted and exploited, the overall reef fishery and the human populations that depend on it may become imperilled, given these species' significant roles in controlling those lower in the food chain. This study thereby emphasizes the need for balanced fisheries informed by the EAF model in small island fisheries management in order to sustain food security in such regions.
The purpose of this study was to determine the composition of the type of catch, the level of diversity and the dominance index. This research was carried out in the Kulu waters, North Minahasa Regency, from November to December 2020. The fishing gear used was a bottom gillnet with a mesh size of 3 inches. The parameters observed were the species composition (Sc), diversity index (H') and dominance index (C). The results showed that the composition of the dominant fish species caught was the sleek unicornfish (Naso hexacanthus) which was 29.06%, followed by the blue swimming crab (Portunus pelagicus) at 25.64%. The diversity index value of the fish species caught was 2.191 and the dominance index value of the caught fish species was 0.169. In this study, the moderate diversity index and low dominance index value indicate that the bottom gillnet in Kulu waters has a good selectivity, but it is not environmentally friendly.
Study on Bycatch Fish of Gillnets in the Lalowaru Coastal Waters of South Konawe
PROCEEDING The 1st International Seminar, 2017
Information concerning by-catch fish of gillnets is urgently needed in an effort to minimize discarded catches and maximize the utilization of by-catch fish for sustainable fisheries management purpose. The present study aimed to analyze and identify the species of by-catch fish caught by gillnets and assessing the level of gillnet friendly used by fishermen in Lalowaru coastal waters towards the sustainability of fish resources. The study was conducted from February to April 2017. The sampling fish was taken biweekly for 3 months. The fish samples were caught using gillnets mesh size of 1 inch, 11⁄2 inch, 13⁄4 inch, and 2 inch. All fish caught were collected and sorted according to species and then each species counted. The data were analyzed to obtain the proportion of the main catches and by- catch fish (incidental catchanddiscarded catch). The proportion of main catches were 25%, while the proportion of incidental catches and discarded catches were 86% and 14%, respectively. Those data indicate that by-catch fish is over amount than that of the main target of fish. It can be concluded that the gillnet fishing gears used by fishermen constitute non selective fishing gear.
Potency of reef fishes in Tuhaha bay waters, Central Maluku Regency, Maluku Province, Indonesia
IOP Conference Series: Earth and Environmental Science, 2019
The research aimed to provide data on taxa composition, density, standing stock and potency of reef fishes at Tuhaha bay waters in 2017. There were 35 families, 105 genera and 243 species of reef fishes found in Tuhaha bay. Four areas of coral reef at good until excellent categories and various habitat had high species richness of reef fishes. Species richness, density and standing stock of major reef fishes species were higher than target and indicator species. Potency (biomass) of economically food fish (target species) ranged from 1.65 - 5.59 tons ha−1 of coral reef (total 2.93 tons ha−1). Total potency, Maximum Sustainable Yield and Allowable Total Catch of economically food fish in 389,70 ha of Tuhaha bay coral reef area were 1,141.82, 590.91 and 456.73 tons, respectively. The status of reef fishes in two coral reef areas belonged to a high category, while the other nine areas had a moderate category.
AACL Bioflux, 2020, Volume 13, Issue 4., 2020
The coral reefs in the coastal waters of the Spelman Strait are experiencing continuous environmental degradation due to exploitation by fishermen. This study, therefore, aims to identify the target fish catch based on the fishing season using local, domestic, and international reef marketing systems. This research was conducted from January to April (west monsoon season) and May to November 2019 (east monsoon season). The results showed that Lutjanidae (6 species), Serranidae (8 species), Prettodidae (1 species), Haemulidae (1 species), Caesionidae (1 species), Ostraciidae (1 species), Mullidae (6 species), Labridae (2 species), Siganidae (3 species), Holocentridae (1 species), Lethrinidae (7 species), Symphysanodontidae (1 species), Chaetodontidae (1 species), Platycephalidae (1 species) and Nemipteridae (3 species) are the identified genera of fishes found in coastal waters of the Spelman Strait. During the west monsoon season, fishermen use the hook sizes numbered 5 and 8 to catch a large size fishes of the Serranidae and Lutjanidae families, and in the east monsoon season, hook sizes of 15, 16, 17 are utilized for catching small fish species. These reef fishes are internationally marketed in other Asian countries such as Singapore, Taiwan, and China.