• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.349-356
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• 2017

The catch composition of commercially important species of the stationary lift net at Barangay Gines, Miagao, Iloilo, the Philippines was investigated from December 2013 to May 2014 during the different phases of the moon. A total of 486 kg of fish coming from 12 different genera, including mollusk and crustaceans, was caught and identified from the catch of the stationary lift net. Among the 12 genera identified from the catch of stationary lift net, anchovy (Stolephorus), sardines (Sardinella), squid (Loligo) and mysid shrimp (Acetes) were considered to be commercially important due to their value. Acetes catch was highest during the new moon in the month of January. Loligo catch was also high during the new moon except in the month of May. Stolephorus catch was also highest during the new moon except in the month of January. Sardinella catch was highest during the first quarter in the month of February. Full moon had the lowest catch all throughout the duration of the study while new moon had the highest catch during December 2013 to March 2014 and first quarter was the highest in the months of April and May.

• Journal of Aquaculture
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• v.22 no.1
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• pp.92-99
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• 2009

Population dynamics and sexual maturity of Neomysis japonica (Ishikawa and Oshima, 1951) were investigated from a shrimp farm in Tae-an, Korea. N. japonica was collected monthly at the shrimp farm belonging to the Marine and Fisheries Research Institute, the Soonchunhyang University from October 2002 to September 2003. The proportion of female was higher than that of male. The mean carapace length of male (2.42 mm) was larger than that of female (2.31 mm). Brood size increased with increasing female body size. The size of N. japonica at 50% sexual maturity was approximately 4.4 mm. N. japonica females grew faster and reached larger size than males. The mortality rate (z) calculated by length-converted catch curves was $3.46\;yr^{-1}$. The annual recruitment pattern of N. japonica had two major peaks. Log-transformed total length was significantly related with log-transformed carapace length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.599-607
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• 1986

Acute toxicity of crude oil (WSF) on the mortality and respiration rates of Neomysis awatschensis was examined. This experiment was conducted by static and short-term bioassay procedure. In lethal test, the test animals were exposured to 8 different concentrations to determine $LC_{50}$ value (median lethal concentration). The concentrations of total hydrocarbon of 96-hr $LC_{50}$ value at $14^{\circ}C\;and\;20^{\circ}C$ were 1.01 ppm and 0.78 ppm, respectively. $LT_{50}$ (the median lethal time) also was determined. The $LT_{50}$ of 0.56 ppm was found within 100 hours, while the $LT_{50}$ of 5.6 ppm was 21 hours at $14^{\circ}C$. At $20^{\circ}C$, the $LT_{50}$ values of 0.56 ppm and 5.60 ppm were 95 hours and 17 hours, respectively. There was little difference between two temperature experiments. The effect of WSF on respiration rate was more sensitive than that on mortality, but no considerable difference was shown between different concentrations in this experiment. The results of these experiments indicated that relatively low concentration of dissolved crude oil fraction can impact on small crustacean in the marine ecosystem.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.1
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• pp.36-42
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• 2015

To determine the predation rate of threadsail filefish, we conducted feeding experiment of threadsail filefish, Stephanolepis cirrhifer on different life stages (medusae, ephyrae, and polyps) of Aurelia aurita s.l. in the laboratory. All size groups of threadsail filefish actively preyed on moon jellyfish Aurelia aurita s.l. and predation rate was proportional to the wet weight of threadsail filefish. Average wet weight 0.5, 1, 2.2 g of threadsail filefish preyed on average $0.77{\pm}0.51g\;fish^{-1}h^{-1}$ of medusae. Average wet weight 150 and 344 g of threadsail filefish preyed on $9.26{\pm}1.61$ and $15.89{\pm}3.67g\;fish^{-1}h^{-1}$ of medusae respectively. In ephyrae and polyps, average wet weight 3.7 g of juvenile of threadsail filefish preyed on 100 ephyrae within 10 minutes and average wet weight 2.2 g of juvenile of threadsail filefish preyed on $5.73{\pm}0.59$ polyps $g^{-1}$ of fish $h^{-1}$. Whereas adults of threadsail filefish did not prey on polyps. In feeding preference experiments to elucidate whether threadsail filefish prey on moon jellyfish in the sea, adults of threadsail filefish preyed on mostly oysters (ca. 60%) and polychaetes (ca. 80%). Medusae were consumed only 2% of total. However, juvenile of threadsail filefish preyed on ephyrae and polyps as well as mysid shrimps. Besides, polyps were consistently consumed during the experiment. Although juvenile of threadsail filefish consumed all kinds of prey, they ceased feeding at temperatures below $11^{\circ}C$, which suggests that possibility of predation on ephyrae may be very low in the sea because ephyrae are released at low temperatures below $11^{\circ}C$ from March to April. Whereas polyps are inhabitable in all seasons in Korean coastal waters, juvenile of threadsail filefish may prey on polyps in the sea. These results suggest that removing moon jellyfish at polyp stage by using juvenile of threadsail filefish is the most effective way for extermination of moon jellyfish.