• Journal of the Korean Society for Marine Environment & Energy
• /
• v.9 no.3
• /
• pp.160-167
• /
• 2006

Harpacticoid copepod Tigriopus japonicus is widely distributed in coastal waters of Korea and plays important role in marine trophic structure as a first consumer. In this study, a series of experiment were conducted to test the potential of the species as a standard test species for marine bioassay. Tolerance on salinity and pH, sensitivity on the reference materials(copper sulfate and cadmium chloride) and response on the ocean dumping materials(waste sludge) we re tested to identify if the species satisfy the basic criteria as standard species for marine bioassay. The nauplius of the species($100{\sim}200{\mu}m$) showed wide tolerance on salinity with >90.0% survival rates exposed to $5.0{\sim}35.0psu$ for 48 h. Wide adaptability on pH's were also observed from 6.3 to 8.2 with >90.0% survival rates during the test. $LC_{50}$ values for copper sulfate and cadmium chloride were $3.6{\pm}0.7ppm,\;1.7{\pm}0.8ppm$, respectively. The variations in mortality between replicates were less than 10.0%. Comparison of $LC_{50}$ values indicated that T. japonicus nauplius was lower sensitive to copper sulfate than the most marine crustaceans included copepods, however, the sensitivity of test animal to cadmium chloride higher than the adults of copepod T. japonicus, Paracalanus parvus, and marine rotifer Brachinonus plicatilis. There were significant concentration-response relationship in the mortality of T. japonicus nauplius using the elutriates of three ocean dumping materials(industrial waste sludge). 48 h $LC_{50}$ values we re $31.1{\pm}1.1%$ for the elutriate of sludge from leather processing company and $54.4{\pm}15.1%$ for that of dye production company. Based on the above experimental results, bioassay using benthic harpacticoid T. japonicus nauplius must be a good estimation tool for marine ecotoxicological assessment of waste or chemicals. Wide tolerance on the salinity and pH, and significant linear relationship between concentration and response(mortality) supported the high potential of the species as a standard test species.

• Korean Journal of Ichthyology
• /
• v.25 no.2
• /
• pp.82-89
• /
• 2013

The spawning behavior, development of eggs and larvae of the Five striped damselfish, Abudefduf vaigiensis were studied. The Five striped damselfish were caught at Dolsan Island, Yeosusi, Jeollanamdo from May in 2011. As a result of observation, male fish attracted female after cleaning the rock. Female left after spawning and male protected their eggs until they had hatched out. The fertilized eggs were elliptical in shape (mean long diameter: 1.06 mm; mean short diameter: 0.55 mm) and transparent. Larvae hatched at 53 hrs after fertilization in $24.5{\sim}26.5^{\circ}C$(mean $25.0^{\circ}C$). The newly hatched larvae were 2.55~2.86 mm (mean 2.71 mm, n=10) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postlarva stage. 3 days after hatching postlarva was measured 2.74~2.97mm(mean 2.84 mm, n=10) in total length. 10 days after hatching postlarva was measured 3.85~4.20mm(mean 4.00 mm, n=10) in total length with dosal fin rays IV-5; ventral fin rays I-3; caudal fin rays 1~2.

• Journal of Aquaculture
• /
• v.18 no.2
• /
• pp.107-114
• /
• 2005

Clownfish are important and very popular fish in the ornamental aquarium industry. Demand for the fish is increasing dramatically. The present study was conducted to verify methods of broodstock management, patterns of spawning, rates of egg hatching and estimates of larval growth fur the saddleback clownfish, Amphiprion polymnus. Spawning occurred 8 times between August 2002 to June 2004 with 2 females and 1 male participating. Fertilized eggs were separated by an adhesive matrix and were oval in shape. The eggs were $2.46{\pm}0.13mm$ in size as measured along the longest axis. The percentage of fertilized eggs was 96.7%. Hatching was observed seven days post-spawning and hatching rate was 85.5%. The sizes of the newly-hatched larvae were $4.58{\pm}0.21mm$ TL (total length). Larvae had an open mouth and anus, and an oval yolk sac. At the 1 st day after hatching, the sizes of the larvae were $4.90{\pm}0.35mm$ TL. The larvae began to eat rotifers after complete yolk absorption. On the 5th day post-hatch, larvae were $5.88{\pm}0.31mm$ TL with complete fins and the survival rate was 48.6%. At 8 days after hatching, a band began to appear on head and back of the larvae indicating the beginning of metamorphosis. Metamorphosis was completed at an average TL of $15.00{\pm}2.12mm$ on the 23rd day after hatching. By the 45th day after hatching, juveniles averaged $22.76{\pm}3.22mm$ TL and survival rate was 28.4%.