scholarly journals BEBERAPAASPEK BIOLOGI IKAN OSKAR (Amphilophus citrinellus) DI WADUK IR. H. DJUANDA, JATILUHUR, JAWA BARAT

2017 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Sri Endah Purnamaningtyas ◽  
Didik WahjuHendro Tjahjo
Keyword(s):  
Economic Value ◽  
Mesh Size ◽  
Food Habit ◽  
Small Fish ◽  
Fish Feed ◽  
Insect Larvae ◽  
Additional Food ◽  
Gonad Maturity ◽  
Amphilophus Citrinellus ◽  
Territorial Water

Ikan oskar (Amphilophus citrinellus) telah berkembang pesat di Waduk Ir. H. Djuanda, di mana keberadaannya dianggap meresahkan pada kebanyakan nelayan setempat. Ikan ini mempunyai nilai ekonomis yang rendah dan bersifat omnivora-karnivora, diduga perkembangan ikan ini mampu mendesak perkembangan jenis ikan lainnya di perairan tersebut. Tujuan dari penelitian ini adalah untuk mengetahui beberapa aspek biologi ikan oskar, meliputi pola kebiasaan pakan ikan, tingkatkematangan gonad, dan fekunditas yang dilakukan di Waduk Ir. H. Djuanda, Jatiluhur. Penelitian ini dilakukan pada bulan Maret, Juni, Agustus, Oktober, dan Desember 2006. Pengambilan contoh ikan menggunakan gillnet percobaan dengan ukuran mata jaring 1; 1,5; 2; 2,5; 3; 3,5; dan 4 inci. Ikan oskardi waduk Ir. H. Djuanda merupakan ikan omnivora-karnivora yang memanfaatkan tumbuhan dan ikan sebagai pakan utamanya, larva serangga, dan fitoplankton sebagai pakan tambahan dan serangga, detritus dan zooplankton sebagai pakan pelengkap. Dari hasil pengamatan yang dilakukan didapatkan bahwa ikan oskar dapat berkembang dan bertelur sepanjang waktu dan fekunditasnya berkisar antara 1.595-3.567 butir. Oskar (Amphilophus citrinellus) has rapidly expanded in Ir. H. Djuanda Reservoir, where existence of the fish is assumed fretting by local fishermen. This fish has low economic value and the character is omnivore-carnivore, development anticipation of this fish can depress growth of other fish species in the territorial water. This research aims to know some biology aspects of Oskar in Ir. H. Djuanda Reservoir, such as food habit, level of gonad maturity, and fecundity. This study is conducted in March, June, August, October, and December 2006. Gillnet with mesh size of 1; 1.5; 2; 2.5; 3; 3.5; and 4 inch were used for fish sampling. This species is categorised in omnovora-carnivora fish feed mainly on plant and small fish, while insect larvae and phytoplankton as additional food and insect, detritus andzooplankton as complement food. From this study resulted thet oskar could develop and spawn in a long season with fecundity range from 1,595-3,567 grains.

scholarly journals Innovative Technology in Increasing the Value-added of the Remnants of Fishing Trawlers in Bagan Percut Village, Percut Sei Tuan

2018 ◽  
Author(s):  
Andysah Putera Utama Siahaan ◽  
Rusiadi
Keyword(s):  
Economic Development ◽  
Economic Value ◽  
Value Added ◽  
Raw Material ◽  
Added Value ◽  
Primary Data ◽  
Innovative Technology ◽  
Small Fish ◽  
Fish Feed ◽  
Economic Market

The phenomenon of economic inequality between coastal cities and villages is a vital issue for economic development. Breakthrough development strategies need to be sought in order to overcome poverty and equitable development outcomes. Funding sources limit regional economic development, which is carried out by the government in order to realize the planning action is not accommodated in the present. The purpose of this study was to analyze the economic value that was neglected from the remaining catches of Pukat Layang fishers, an inventory of various economic commodities that could be generated from the remaining catch of fisherman flyover and add economic value added and management of the remaining trawler catches which were processed into economic commodities. The method used for primary data collection with observation and experiment techniques. Primary data is obtained directly from official publications. Data analysis used descriptive and comparative techniques before and after treatment. The results of the remaining catch of Pukat Layang fishers have economic market value as an ingredient in the consumption of anchovy, salted fish, as raw material for making fish feed and as jewelry and accessories. Commodity value of economic potential from the remaining catch of Pukat Layang fishermen: anchovy, clamshell, centipede shrimp, small squid, crunchy skin, small fish. Value added to commodities that can be consumed, anchovy, squid, small, and small fish. The added value of small crabs, small fish, and small shrimp/centipede shrimp can be used as the fish meal for feed ingredients.

scholarly journals Ethnobotany of suweg, Amorphophallus paeoniifolius: Utilization and cultivation in West Java, Indonesia

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
ASEP ZAINAL MUTAQIN ◽  
DENNY KURNIADIE ◽  
JOHAN ISKANDAR ◽  
MOHAMAD NURZAMAN ◽  
Ruhyat Partasasmita
Keyword(s):  
Rural Areas ◽  
Economic Value ◽  
Age Groups ◽  
The Elderly ◽  
Food Sources ◽  
Ecological Knowledge ◽  
Fish Feed ◽  
Structured Interviews ◽  
West Java ◽  
Additional Food

Abstract. Mutaqin AZ, Kurniadie D, Iskandar J, Nurzaman M, Partasasmita R. 2020. Ethnobotany of suweg, Amorphophallus paeoniifolius: Utilization and cultivation in West Java, Indonesia. Biodiversitas 21: 1635-1644. Amorphophallus paeoniifolius (Dennst.) Nicolson, locally known as suweg, is a bulbous plant that has many benefits, but has not been cultivated as intensively as other species from the Araceae family. Suweg grows scattered in various rural areas in Indonesia, including West Java. Some suweg plants are cultivated by villagers, while the others grow wildly in forested areas. Suweg is commonly cultivated in several types of agroecosystems, such as home gardens (pekarangan) and gardens (kebun), using traditional ecological knowledge inherited from generation to generation. This study aims to investigate the utilization and cultivation of suweg by a community in Cisoka Village, Cikijing Sub-district, Majalengka District, West Java. This study used a qualitative method using ethnobotany approach, i.e. an emic analysis of the perception and local knowledge of community on suweg, and then validated using scientific or ethical knowledge. Field data collection was done by observation and semi-structured interviews with key informants chosen purposively considered having expertise and knowledge about suweg. The results showed that suweg has long been cultivated or growing naturally in Cisoka Village. The species has been culturally utilized by the rural community as additional food sources of carbohydrates, fish feed, and traditional ceremonies. However, the use of traditional ceremonies has been lost its importance. Suweg is generally used by the elderly, with certain groups, such as rural fish farmers and some younger age groups or children who like suweg. The rural people of Cisoka Village also mentioned that suweg was not cultivated as intensively as other. This is partly because it is considered not to have a high economic value as other agricultural commodities.

scholarly journals HUBUNGAN PANJANG- BERAT, KEBIASAANMAKAN DAN KEMATANGANGONAD IKAN BILIH (Mystaecoleucus padangensis) DI DANAUTOBA, SUMATERAUTARA

2017 ◽  
Vol 3 (6) ◽  
pp. 351
Author(s):  
Chairulwan Umar ◽  
Endi Setiadi Kartamihardja
Keyword(s):  
Growth Pattern ◽  
Average Length ◽  
Mesh Size ◽  
Food Habit ◽  
Average Weight ◽  
Additional Food ◽  
Gonadal Maturity ◽  
West Sumatra ◽  
Biological Aspects ◽  
Intensive Fishing

Ikan bilih (Mystacoleucus padangensis Bleeker) diDanau Toba adalah jenis ikan introduksi dari Danau Singkarak, Sumatera Barat. Pada saat ini terdapat kecenderungan ukuran individu menurun, hal ini antara lain disebabkan oleh penangkapan yang intensif menggunakan alat tangkap bagan apung dengan ukuran mata jaring relatif kecil (< 1,25 inci). Penelitian ini bertujuan untuk melihat beberapa aspek biologi meliputi ukuran panjang dan bobot, kebiasaan makan, tingkat kematangan gonad dan fekunditasnya. Hasil penelitian diperoleh hubungan panjang dan bobot individu bersifat allometrik positif dengan panjang total rata-rata 12,6 cmdan bobot rata-rata 19,8 g/ekor. Dari analisa lambung ikan bilih pemakan detritus (78,2 – 92,9 %), fitoplankton dan zooplankton sebagai pakan tambahan (4,9 – 11,5 %) serta seresah tumbuhan sebagai pakan pelengkap (1,9 – 1,8 %). Hasil pengamatan ikan bilih yang matang gonaddiperoleh nilai fekunditasnya rata-rata berkisar antara 5.262 – 16.117 butir telur. Hasil pengamatan TKG dan jumlah telur menunjukkan ikan bilih dapat bertelur danmemijah sepanjang tahun dan berkembang dengan baik sehingga ikan ini tetap lestari walaupun adanya eksploitasi yang cukup intensif. Bilih (Mystacoleucus padangensis Bleeker) in Toba Lake was introduce from Singkarak Lake,West Sumatra. At present the growth was decreased, it caused by intensive fishing and the uses of lift net with small mesh size (under 1,25 inch). This research aims to know some biological aspects of bilih such as length - weight, relationship food habit, level of gonadal maturity, and fecundity. The results showed that growth pattern of bilih positive allometric with average length of about 12,6 cm and average weight of about 19,8 gr/each. Bilih detritus feeding (78,2 – 92,9%), phytoplankton and zooplankton as additional food (4,9 – 11,5%) and seresah tumbuhan as complement food (1,9 – 1,8%). Fecundity of ranged from 5.262 – 16.117. TKG observation and eggs gain showed that bilih could development and spawn in long years and growth well enough, so that bilih can stlll growth rapidly eventhough there is an exploitation.

Size Changes, Mortality, and Equilibrium Yields in an Exploited Stock of American Plaice (Hippoglossoides platessoides)

1969 ◽  
Vol 26 (5) ◽  
pp. 1205-1235 ◽  
Author(s):  
P. M. Powles
Keyword(s):  
Mesh Size ◽  
Food Competition ◽  
Mortality Factor ◽  
Otter Trawl ◽  
Small Fish ◽  
Large Fish ◽  
Age Composition ◽  
Instantaneous Rate ◽  
Factors Affecting ◽  
Ecological Dominance

Records from research surveys and commercial landings for American plaice from the Magdalen Shallows, or the southwestern Gulf of St. Lawrence, showed decreases in percentage of old, large fish and in catch per unit of effort from 1955 to 1962. The changes in age composition were clearly relatable to the fishery, which was mainly by otter trawl. Ricker models indicated that wastage of deck-exposed subcommercial plaice is currently a greater mortality factor than predation by cod. Increased landings in particular years were associated with successful year-classes. Other factors affecting landings were annual differences in fleet dispersal, which were related to movements of cod, a cohabiting species. No clear decrease or increase in absolute recruitment of plaice was demonstratable because quantitative comparisons of research surveys by different vessels using different gears and with different skippers, would be misleading.Mortality estimates of adult plaice by three methods showed agreement, indicating that instantaneous rate of natural mortality was between 0.09 and 0.13. The instantaneous rate of fishing for 1957–62 was 0.46. Increasing mesh-size would reduce cod catches and have little effect in conserving plaice, but marketing small fish would increase plaice landings. Voluntary release of small plaice promptly on capture would help maintain the stock, as would reduction in numbers of large cod, the main predator of small plaice. Increased numbers of small cod since 1959, as reported by other workers, could result in greater food competition with small plaice, effectively reinforcing the ecological dominance of cod over plaice.

scholarly journals Temporal and ontogenetic variations in feeding habits of Hollandichthys multifasciatus (Teleostei: Characidae) in coastal Atlantic rainforest streams, southern Brazil

2009 ◽  
Vol 7 (3) ◽  
pp. 415-420 ◽  
Author(s):  
Vinícius Abilhoa ◽  
Hugo Bornatowski ◽  
Gislaine Otto
Keyword(s):  
Quantitative Methods ◽  
Feeding Habits ◽  
Atlantic Rainforest ◽  
Small Fish ◽  
Fish Feed ◽  
Southern Brazil ◽  
Qualitative And Quantitative ◽  
Qualitative And Quantitative Methods ◽  
Black Water ◽  
Terrestrial Insects

Feeding habits of the characin Hollandichthys multifasciatus were investigated. Samplings were made between March 2004 and February 2005 in two black water streams of the coastal Atlantic rainforest in southern Brazil. The diet, evaluated by qualitative and quantitative methods, included aquatic and terrestrial insects, decapods, oligochaetes, plants and spiders. Large individuals feed mainly on plants, terrestrial insects, and spiders, whereas small fish feed basically on plants and oligochaetes. The species showed an omnivorous feeding habit, and its diet was composed of autochthonous (mainly oligochaetes) and allochthonous (plants and terrestrial insects) material.

Research on supplementary feeding for production of Nile tilapia.

2020 ◽  
Author(s):  
James Diana
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Nile Tilapia ◽  
Economic Value ◽  
Normal Growth ◽  
Supplementary Feeding ◽  
Natural Food ◽  
Small Fish ◽  
First Feeding ◽  
Natural Foods

Abstract Efficient supplementary feeding will utilize not only the feed added to the pond, but also natural food. Feeding improves the growth rate of fish in a pond only when the fish are food limited. Natural foods may provide all of the necessary nutrition for normal growth of small fish, and if growth begins to decline at a larger size, supplementary feeding should yield higher growth rates. One experiment compared the use of fertilizer alone, feed alone, and a combination of feed and fertilizer for growth and production of Nile tilapia (Oreochromis niloticus). Ponds receiving feed and fertilizer had higher growth rates than ponds with feed alone, and both showed considerably higher growth rate than ponds with fertilizer alone. Feeding was necessary to grow fish to a size of over 200 g in a reasonable amount of time. A second experiment tested the possibility that feeding at reduced ration and allowing the consumption of natural food might give a comparable growth rate to feeding alone. In this experiment, full satiation ration, 75% satiation ration, or even 50% satiation ration resulted in similar mean weights at harvest, about 400 g after 150 days. These results indicate that it may be efficient to simply feed the fish at about half of their maximum ration and allow them to eat natural food for the other half of their growth, if the pond is managed well. Economic analysis showed that fertilization resulted in $1,891 ha-1 year-1 of profit, feed only lost almost $3,000 ha-1 year-1, 75% feeding lost $258, 50% feeding yielded $1,765 ha-1 year-1, and 25% feeding yielded $155 ha-1 year-1. If the growth rate were linearly extrapolated until the fish reached 500 g and were then harvested, the 75% feeding would yield $4,835 ha-1 year-1 and the 50% feeding $5,865 ha-1 year-1. A third experiment was conducted to evaluate the timing when first feeding should occur. In this case, fish in ponds were fed once they reached 50, 100, 150, 200 or 250 g in size. The fish grew similarly before they were fed, and then grew again similarly after feeding, with a growth rate under fertilization of about 1 g day-1, and a growth rate under feeding of about 3 g day-1. Fish fed first at 50 or 100 g reached the same ultimate size by the end of the experiment and had similar production levels. Fish first fed at 150 or 200 g also showed similar results and, finally, fish fed at 250 g never reached the targeted size. These results indicate that it is most efficient to wait until the fish reach 100 g before commencing artificial feeding. Economic evaluation showed an annual net profit of $3,700 ha-1 year-1 when the fish were fed first at 50 g, $6,160 at 100 g, $4,800 at 150 g, $1,800 at 200 g and $3,600 at 250 g. Clearly, efficient feeding systems produce higher incomes than less efficient systems, and fertilization alone, if the fish reach a targeted size that has a higher economic value.

Optimal Controls for a Single Species Fishery and the Economic Value of Research

1976 ◽  
Vol 33 (4) ◽  
pp. 793-809 ◽  
Author(s):  
C. C. Huang ◽  
Ilan B. Vertinsky ◽  
Norman J. Wilimovsky
Keyword(s):  
Optimal Allocation ◽  
Probability Distributions ◽  
Economic Value ◽  
Mesh Size ◽  
Single Species ◽  
Complete Information ◽  
Optimal Controls ◽  
Optimal Policies ◽  
Solution Methods ◽  
Parameter Values

Mathematical proofs and analyses of solution methods are presented for determining optimal policies for the management of a single species fishery under equilibrium conditions. Previous intuitive arguments for solution of optimal policies controlling mesh size and fishing rate given complete information are explicitly proven. The analysis is extended to the case where some of the parameters describing the dynamics of the population are known only imprecisely to the manager. Using probability distributions for those unknown parameter values the problem is cast as a stochastic program where expected sustained net revenues from the fishery are maximized. The associated problem of optimal allocation of research resources under uncertainty conditions is considered by evaluating the direct value of such information to management activities.Examples and algorithms are presented for the class of problems discussed.

scholarly journals Identifying indicators of the effects of fishing using alternative models, uncertainty, and aggregation error

2011 ◽  
Vol 68 (7) ◽  
pp. 1417-1425 ◽  
Author(s):  
Sarah J. Metcalf ◽  
Matthew B. Pember ◽  
Lynda M. Bellchambers
Keyword(s):  
Economic Value ◽  
Ecosystem Change ◽  
Small Fish ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Alternative Models ◽  
Qualitative Models ◽  
Lobster Fishery ◽  
Panulirus Cygnus

Abstract Metcalf, S. J., Pember, M. B., and Bellchambers, L. M. 2011. Identifying indicators of the effects of fishing using alternative models, uncertainty, and aggregation error. – ICES Journal of Marine Science, 68: 1417–1425. The identification of indicators of the indirect effects of fishing is often an issue for fisheries management, particularly if just commercial catch data are available. Complex, intermediate, and simplified qualitative models were produced for a fishery case study off Western Australia to identify potential indicators of ecosystem change attributable to western rock lobster (Panulirus cygnus) extraction and bait input. Models of intermediate complexity were used to identify indicators because they produced the least aggregation error. Structural uncertainty was considered through a series of structurally different intermediate models. These alternate models consistently predicted that extraction of rock lobster may positively impact small fish of low economic value, such as old wife (Enoplosus armatus), footballer sweep (Neatypus obliquus), and king wrasse (Coris auricularis). These small fish were therefore identified as potential indicators of the effects of rock lobster extraction. Small crustaceans (amphipods and isopods) also displayed positive impacts attributable to bait input from the rock lobster fishery and were identified as potential indicators of bait effects. Monitoring of these indicators may aid the detection of ecosystem change caused by the rock lobster fishery.

scholarly journals LUAS RELUNG DAN KOMPETISI PAKAN KOMUNITAS IKAN DI SITU PANJALU, JAWA BARAT

2017 ◽  
Vol 3 (3) ◽  
pp. 159
Author(s):  
Astri Suryandari ◽  
Kunto Purnomo
Keyword(s):  
Oreochromis Niloticus ◽  
Fish Community ◽  
Niche Breadth ◽  
Mesh Size ◽  
Stock Enhancement ◽  
Competition Index ◽  
Gill Net ◽  
Amphilophus Citrinellus ◽  
Food Niche

Penelitian ini bertujuan untuk mempelajari luas relung dan kompetisi komunitas ikan di Situ Panjalu. Pengambilan contoh ikan dilakukan pada bulan Mei dan September 2008 denganmenggunakan jaring insang berukuran 2,5; 3,0; dan 3,5 inci. Komunitas ikan di Situ Panjalu terdiri atas ikan nila (Oreochromis niloticus), kongo (Parachromis managuensis), oskar (Amphilophus citrinellus), golsom (Aequidens goldsom), selebra (Amphilopus sp.), dan keril (Aequidens rivulatus). Berdasarkan atas analisis luas relung dan kompetisi pakan, ikan golsom mempunyai potensi untuk berkembang menjadi populasi yang besar di perairan Situ Panjalu dibandingkan jenis ikan lain.Relung pakan yang dapat dioptimalkan adalah fitoplankton sehingga untuk pengkayaan stok dapat dilakukan melalui penebaran ikan herbivora pemakan plankton. The aim of the research was to identified niche breadth and competition among of fishes community in Situ Panjalu. Samples were collected by gill net of 2.5; 3.0; and 3.5 inches mesh size in Mei and September 2008. Fish community in Panjalu consist of tilapia (Oreochromis niloticus), kongo (Parachromis naguensis), midas cichlid (Amphilopus citrinellus), golsom (Aequidens goldsom), selebra (Amphilophus sp.) and keril (Aequidens rivulatus). Based on niche breadth and competition index, goldsom is potentially growth into great population compare to another fishes species in Panjalu. Food niche that could be optimimized was phytoplankton so that stock enhancement could be conducted by stocking the herbivorous fishes feed on phytolankton.

scholarly journals Reproduction of Indian Mackerel Rastreliger kanagurta (Cuvier, 1816) in Morodemak Coast Demak Regency

2020 ◽  
Vol 22 (2) ◽  
pp. 85
Author(s):  
Dwi Rachmanto ◽  
Djumanto Djumanto ◽  
Eko Setyobudi
Keyword(s):  
Economic Value ◽  
Gonad Maturity ◽  
Indian Mackerel ◽  
Central Java ◽  
Length Relationship ◽  
Fish Samples ◽  
Egg Number ◽  
Males And Females ◽  
Relationship Of ◽  
Brood Fish

Indian mackerel is a group of small pelagic fish that has high economic value and is ecologically important. The catch of Indian mackerel in the Morodemak Coastal Fishing Port of Central Java has decreased within 2016-2018, which is suspected by overexploitation. This study aims to observe the reproduction of Indian mackerel. Fish samples were collected from the catches of the mini purse seine operated by fishermen in April-June 2019. The fish samples were measured their length and weight individually, then the abdomen dissected to collect gonad, and counted in sub-sample of the egg number. Data were analyzed to determine the length-weight relationship of fish, sex ratio, gonad maturity level (GML), gonad maturity index (GMI), the size of the first gonad matured, and the egg number in each gonad brood fish. The results showed a negative allometric length relationship, and the length-weight relation equation in female fish was W = 0.038 L 2.59 and in male was W = 0.178 L 2.03. The value of fish condition factors in males, and females obtained values ranging from 1-2. The proportion of fish in GML III ranges from 27.2 to 82.5%, while GML IV ranges from 3.6 to 33.8%. Fish GMI ranged from 0.17 to 4.75%. The eggs number ranged from 11.235 to 40.878 grain. The female Indian mackerel get the first gonad matured at the size of 15.2 cm.

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