Journal Indonesian Fisheries Research Journal

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235 articles
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Hari Eko Irianto, Sri Turni Hartati, Lilis Sadiyah
Indonesian Fisheries Research Journal, Volume 23, pp 69-78; doi:10.15578/ifrj.23.2.2017.69-78

Abstract:The Great Jakarta Bay Ecosystem (GJBE) supports the economic growth for the surrounding community, including fisheries sector. This large ecosystem is consisted of two coastal ecosystems, i.e. Jakarta Bay and Thousands islands. There are only traditional fisheries operating either in Jakarta Bay or Thousand islands. Some economically important fisheries include shrimp, demersal and small pelagic fisheries, which are caught using different fishing gears, either active or passive fishing gears. There are some serious concerns related to the fish resources and habitat degradations in the GJBE, which in turn can cause the decrease in fish population and fish species diversity, respectively. CPUE and catch composition of the fixed lift nets, sero and fixed gillnet fisheries were obtained from the observations in 2006 and 2014. In addition, to determine the level of pollution, tissue samples were collected for green mussel (Perna viridis), blue swimming crab (Portunus pelagicus) and white-spotted spinefoot (Siganus canaliculatus) in 2009. The CPUE trend and catch composition showed that overfishing might have been occurring in the Jakarta Bay. The histological study on gill tissues of the three species shows that the Jakarta Bay has been polluted. Several efforts have been done to address the problems, including sea farming, habitat rehabilitation (artificial reef and mangrove restoration), marine conservation area and fish shelter, restocking and sea ranching.
Asep Priatna, Suprapto Suprapto
Indonesian Fisheries Research Journal, Volume 23, pp 79-87; doi:10.15578/ifrj.23.2.2017.79-87

Abstract:Any fish on swept area of bottom trawl could not be caught due to some technical factors during towing. However, it could be estimated by integrated of bottom trawl and acoustic survey. This paper describes the determination of some factors that affect the performance of trawl net during the bottom trawl survey in the waters of Tarakan. Surveys were carried out in May, August, and November 2012. A total of 57 stations of simultaneously acoustic-trawl were completed. Data collected from each station include catch composition, and variables of trawling operation (i.e. bottom depth, warp length, trawl door opening, towing speed, towing duration, and acoustic fish density). Principal component analysis was applied to identify variables might impact of trawling performance (i.e. fish density at the waters area, towing speed, towing duration, warp length, horizontal opening of trawl door, density of non-demersal at cod end, and bottom depth). Both towing speed and towing duration were not major component for trawl operation. According to test of significance for four variables (i.e. bottom depth, warp length, horizontal opening, biota non-demersal at cod end) which affected to fish density at waters area, that both of variable (i.e. warp length and bottom depth) were significant as the principal components for the performance of bottom trawl.
Achmad Zamroni, Suwarso Suwarso
Indonesian Fisheries Research Journal, Volume 23, pp 89-96; doi:10.15578/ifrj.23.2.2017.89-96

Abstract:Mackerel scads (Decapterus macarellus) is a small widely distributed pelagic species in ocean. In 2013, monthly catch and abundance index of mackerel scads increased in western part of Sumatera waters. High exploitation of mackerel scads may lead to decrease stock due to the over exploitation. Stock information is very useful for calculating of the potential fish. Genetic analysis is one of the powerful tools to estimate fish stock quickly. Genetic diversity of mackerel scads in this study was analyzed using RFLP (Restriction Fragment Length Polymorphism) with AfaI, EcoR I, HapII, HinfI and TaqI restriction enzyme. The results showed that the lowest genetic diversity of mackerel scads was Labuan population. Kinship Labuan was also the furtherest stock compared to other populations. It can be concluded that the population of Labuan is derived from a different sub-species. The closest kinship was between Aceh and Sibolga stock.
Mujiyanto Mujiyanto, Riswanto Riswanto, Dharmadi Dharmadi, Wildan Ghiffary
Indonesian Fisheries Research Journal, Volume 23, pp 55-67; doi:10.15578/ifrj.23.2.2017.55-67

Abstract:Dolphins are one of the most interesting cetacean types included in family Delphinidae or known as the oceanic dolphins from genus Stenella sp. and Tursiops sp. Migration and abundance of dolphins are affected by the presence of food and oceanographic conditions. The purpose of this research is to determine the composition and distribution of dolphins in relation to the water quality parameters. Benefits of this research are expected to provide information on the relationship between distributions of the family Delphinidae cetacean (oceanic dolphins) and oceanographic conditions. The method for this research is descriptive exploratory, with models onboard tracking survey. Field observations were done in November 2015 and period of March-April 2016 outside and inside Savu Sea National Marine Park waters. The sighting of dolphin in November and March-April found as much seven species: bottlenose dolphin, fraser’s dolphin, pantropical spotted dolphin, risso’s dolphin, rough-toothed dolphin, spinner dolphin and stripped dolphin. The highest species distribution noted in the Savu Sea is spinner dolphin, pantropical spotted dolphin, rough-toothed dolphin and frazer’s dolphin. The existence of dolphins in Savu Sea is more related with sea surface temperature than others oceanographic parameters. This condition is suspected due to the influence of sea surface temperature to body temperature of dolphin especially for foraging activities. The habit of dolphin is more active around Sumba Island and Daratan Timor waters while in the evening the animal is usually going to Manggarai and Rote Ndao Islands waters to rest.
Darwanto Darwanto
Indonesian Fisheries Research Journal, Volume 23, pp 116-118; doi:10.15578/ifrj.23.2.2017.app.116-118

Darwanto Darwanto
Indonesian Fisheries Research Journal, Volume 23; doi:10.15578/ifrj.23.2.2017.i-vii

Mohamad Natsir, Agustinus Anung Widodo, Wudianto Wudianto, Sveinn Agnarsson
Indonesian Fisheries Research Journal, Volume 23, pp 97-105; doi:10.15578/ifrj.23.2.2017.97-105

Abstract:Kendari fishing port is one of the biggest tuna fisheries landing in Indonesia. It yearly average tuna production was more than 20 thousand tons. The tuna fishing fleet in Kendari use FAD (Fish Aggregating Devices) as an auxiliary fishing gear. FAD management is major issues in Indonesian tuna fisheries. extensive investment on FAD has led to increase of the juvenile and by catch and also social problem because of the competition. Technical efficiency analysis was done during this study, 2015 catch and logistic data from Kendari fishing port was run using stochastic frontier to obtain the model. Mean value technical efficiency was 0.534. Purse seine the highest mean value compared to other fishing gear. All the variables input show positive relationship to the catch except the days at sea variables, this is a signal that the increasing number of FAD has made the fisherman spend more time at sea it will decrease the technical efficiency. The results support the need of FAD regulation done by the government of Indonesia. Regulation will keep the number of FAD at optimum level and increase the technical effieciency so the fisheries keep gaining the optimum benefit from the resources.
Ria Faizah, Lilis Sadiyah, Moh. Fauzi
Indonesian Fisheries Research Journal, Volume 23, pp 107-115; doi:10.15578/ifrj.23.2.2017.107-115

Abstract:Kwandang waters is one of the main base for small pelagic fisheries in Sulawesi sea in which the Indian mackerel (Rastrelliger kanagurta) has been exploited. The objective of the research was to estimate the population parameters, exploitation rate and reproductive biology of Indian mackerel. Length frequency data were collected from PP Kwandang, between February and October 2012. Estimation of population parameters of Indian mackerel was done using FISAT II method. The results showed that growth rate as follows (K) = 0,80 year-1 , L∞=27,3 cm. Total mortality rate (Z) = 2,72 year-1, with natural mortality (M) = 1,29 year-1 and fishing mortality (F) = 1,43 year-1 and exploitation rate (E)=0,53. Exploitation of Indian mackerel in Kwandang waters have reached its optimum level. The sex ratio of Indian mackerel was balance. The most commonly found is Gonado Maturity Stage of I. Based on the results, it is necessary to manage with the responsible management through gradually increasing of the mesh size of the gears or restricting additional lift net or by restricting fishing for certain seasons or declaring fish sanctuaries in certain areas, especially in spawning grounds to protect the Indian mackerel.
Irwan Jatmiko, Humber Andrade, Budi Nugraha
Indonesian Fisheries Research Journal, Volume 23, pp 7-15; doi:10.15578/ifrj.23.1.2017.7-15

Abstract:Relative abundance indices as calculated based on commercial catches are the input data to run stock assessment models to gather useful information for decision making in fishery management. A Generalized Linear Model (GLM) was used to calculate relative abundance indices and effect of longline fishing gear configuration. Data were collected by a scientific observer program from August 2005 to November 2013. Most of the boats monitored were based in the Benoa Port, Bali. Catches are often equal to zero because swordfish is a bycatch for Indonesian longline fleets. Therefore, a hurdle model and a binomial distribution was used to model the proportion of positive catch rates, while a gamma distribution were used to model the positive longline sets. Correlations between the proportion of positive sets and year () and quarter () were weak. However, linear correlation between the proportion of positive sets and the length of branch lines () and number of hooks between floats () were negative and significant. The probability of success is higher for surface longline with small number of hooks and short branch lines. Models with year in interactions as random effects did not converge. Models with year in interactions as fixed effects did converge, but the estimation of standard errors of year coefficients were high. Meaningful estimations were obtained only when using the simplest model, in which year is not in interactions. The low proportional decrease of deviance indicates that most of the variability of catch rates of swordfish caught by Indonesian longline boats are not related to year, quarter, number of hooks between floats and the length of branch lines. Other variables and information, like the daytime while the longlines deployed in the water (day or night), type of bait, size and type of hooks, and if the fishermen use light-sticks to attract the fish, are necessary to better understand the catch rate, and improve the estimations of the relative abundance indices.
Bram Setyadji, Irwan Jatmiko
Indonesian Fisheries Research Journal, Volume 23, pp 1-6; doi:10.15578/ifrj.23.1.2017.1-6

Abstract:Indonesian tuna longline fleets have been fishing in the Exclusive Economic Zone (EEZ) and high seas of the Indian Ocean for quite some time. However, effort has never been made to separate catch from the EEZ and the high seas as it important for fisheries management. A total of 2,430 set-by-set longline fishing data had been collected by scientific observers based in the Research Institute of Tuna Fishery in Bali since August 2005 to December 2014 on which present analysis was made. The research aims to compare between trend of tuna catch of the EEZ and of the high seas of Indian Ocean. The results show that the mean hook rate of both catches of big eye tuna (BET) and southern Bluefin tuna (SBT) caught in the high seas was significantly higher than that the EEZ (two sample t-test, p0.05).
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