Metal halide (MH) lamp is applied in light fishing purse seine (PS). This lamp have weaknesses like wasteful energy, it is necessary to replace with energy saving lamp. Light emitting diode (LED) is potential to replace the MH. The experimental method in order to obtain data on different light intensity, fuel consumption, and number of catch in PS fishing using MH and LED lamps as fish attractor. Light intensity observations were done on each of 6 MH and LED lamps in the distance of 0-17 m. The LED lamp had focus more onto the front that enabled to reach farther distance, MH lamp had dispersed illumination distance. The LED lamp is more efficient in directing the lamp into the water. The number addition of MH lamps on different side of vessel does not increase the total amount of light intensity significantly. The ratio of the number captures of MH and LED lamps is 3.57:1 is much lower than the electric power ratio of both lamps (40:1). So that if the electric power LED lamps increased 6.2 times from 600 W to 3,875 W then the total number of fish from the LED lamps will approach the MH lamps.
Fringescale sardine (Sardinella fimbriata) is small pelagic fish that has an increasing production every year. This can trigger the occurrence of overfishing, so it is necessary to study the biology and dynamic population of fish. This research was conducted in December 2016 -May 2017. The purpose of this research was to determine the biological aspects and population dynamic of fringescale sardine (S. fimbriata) in Bali Strait. Samples were obtained from surface gillnet landed in Muncar fishing port, with 1471 of fish. Results showed that sex ratio was about balanced with the proportion of 55% male and 45% female. Length and weight relationship was negative allometric patterns. Length of first mature (Lm) male and female was 11.95 cm and 10.79 cm respectively. Based on dynamics population analysis it was found that length at first capture (Lc) was 10.44 cm. While K, L∞ and t0 were 0.54/year, 19.6 cm and -0.149 year respectively. In addition there was only one peak recruitment occured in 7th month of recruitment pattern. Another analysis indicated that a value of natural mortality (M) was 1.38 with sea surface temperature (SST) of 29.45°C. According to length frequency data total mortality (Z) was 6.41 so that fishing mortality (F) was calculated to be 5.03. Hence value of exploitation rate (E) was 0.79. It can be concluded that the fisheries resources status is categorized as overfishing.
Little tuna landed there are three types: Euthynnus affinis, Auxis thazard, Auxis rochei. The analysis shows the condition of the resource indicates the condition Over Exploited. Length and weight relationship tuna (Auxis thazard) total positive allometric Length of first caught fish (Lc) of 27.08 cm, The length at first maturity (Lm) 28.39 cm Lt = 35.40 {1 − e −0.58(t + 0.26)}, total mortality (Z) = 4.08 per year, Fishing mortality (F) = 2.91 per year, natural mortality (M) = 1.17 per year, with the Exploitation rate (E) = 0.71 per year which, if E> 0.5 is overfishing. The relationship between length and weight of Tuna (Euthynnus affinis) was unsexed W = 0.1078 L 3.48. The value of Lc and Lm were 37.51 cm, 38.43 cm, and 40.17 cm respectively. Von Bertalanffy growth Lt = 72.50 {1 − e −0.11(t +0.27)} equation of this study was. The rate of total mortality (Z), natural (M), and catch (F) were respectively 0.56, 1.74 and 0.01. The peak season tuna catch in PPN Prigi was occurred in September (515.865%) with the low season occurred in January (1.244%). As for UPT PP Muncar, the peak season cob arrest took place in March (316.315%) with famine in February (6,651%). Little Tuna food was consist of 7 groups, namely: small fish, shrimp, Ascomycota, Chloromonadophyta, Chyanophyta, Chrysophyta, and Chlorophyta.
Jatigede Reservoir in Sumedang Regency is a land mass planning designed as a multi-function reservoir. The main water source for this reservoir is from Cimanuk River, which flows through Garut Regency, and has many industrial activities around the river flow. This research was conducted to assess the trophic status of water pollution in Jatigede Reservoir by utilizing plankton as a bioindicator agent. Samples were collected from 9 observation stations from November 2018 until January 2019. The results showed that 26 species of phytoplankton from 7 divisions including Dinophyta, Cyanophyta, Chlorophyta, Chrysophyta, Euglenophyta, Bacillariophyta, and Charophyta was found in Jatigede Reservoir at about 461 ind/m3. Zooplankton abundance of 6 species from 2 divisions of Rotifera and Copepoda at 2 ind/m3. The average phytoplankton diversity index was 0.93 and zooplankton diversity index was 0.23. The average phytoplankton evenness index was 0.44 and zooplankton evenness index was 0.24. The average dominance of phytoplankton was 0.58 and dominance of zooplankton was 0.25. Based on the plankton community structure, the trophic status of Jatigede Reservoir was classified to moderate polluted (eutroph) to heavily pollutants (hypereutroph). The dominant species was Perinidium sp from Dinophyta division.
Stingray (Batoidea) are often caught as bycatch in south coast of Prigi waters. The stingray resource has very limited in number and require a long time to reproduce. Attention must be paid to avoid the extinct of stingray resource. This research aimed to justify species composition and identify length weight relationship, sex ratio, and clasper maturity level of stingray (Batoidea) caught in south coast of Prigi waters. The research was carried out from December 2019 to April 2020 at Prigi archipelago fishing port as landing place. This study used a quantitative descriptive method with the number of samples that were successfully obtained as many as 97 stingray. During the study, 6 species of stingray (Batoidea) were identified, namely Taiwan guitarfish (Rhinobatos schlegelii), blotched fantail stingray (Taeniurops meyeni), Japanese devilray (Mobula japanica), bluespotted maskray (Neotrygon kuhlii), shark ray (Rhina ancylostoma), dan bluespotted fantail ray (Taeniura lymma). Result indicated that Taiwan guitarfish (R. schlegelii) and bluespotted maskray (N. kuhlii) were two dominant stingray species in south coast of Prigi waters with proportion of 47.42% and 41.24% respectively. Disk width (Dw) and weight (W) of Taiwan guitarfish (R. schlegelii) ranged from 15.2 cm to 24.6 cm and from 268 gr to 1060 gr respectively and bluespotted maskray (N. kuhlii) ranged from 17.3 cm to 39.3 cm and from 140 gr to 2006 gr respectively. Another analysis showed that Taiwan guitarfish (R. schlegelii) and bluespotted maskray (N. kuhlii) had length weight relationship equations W = 0.0202 Dw34699 and W=0.0351*Dw29848 respectively. The sex ratio of Taiwan guitarfish Taiwan guitarfish (R. schlegelii) dan bluespotted maskray (N. kuhlii) was 1:1.4 and 1:1.2 respectively. In addition, clasper maturity level of the Taiwan guitarfish (R. schlegelii) and bluespotted maskray (N. kuhlii) species was dominated by Non-Calcification (NC). In conclusion, The stingray (Batoidea) caught in south coast of Prigi waters were dominated by Taiwan guitarfish (R. schlegelii) and bluespotted maskray (N. kuhlii). Length weight relationship of Taiwan guitarfish (R. schlegelii) and bluespotted maskray (N. kuhlii) was allometric positive and isometric respectively. Both of them was in balance condition sex ratio and was dominated by immature stage. Hence fishing activities in south coast of Prigi waters should avoid the stingray as bycatch in order to preserve the stock.
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