Dae-Soo Chang

Seasonal variation and species composition of fishes communities in artificial reef unit at marine ranching area in the coastal waters off Jeju island, Korea

This study monitored a variety of marine fish communities in artificial reefs unit of the total 5 types (Dice type, Octagonal turtle type, Two-stage tube type, Gazebo type, Tetrapod type) which are located in the marine ranching at Jeju island by scuba diving in May, July, October and December 2009. Underwater photographing was accomplished at total 3 phases (condition of artificial reefs photographing, concentric circle movement photographing and line transect photographing). The preservation condition of artificial reefs facility was very good, and the dominant species were Chromis notatus, Sebastes thompsoni, Oplegnathus fasciatus and Halichoeres poecilopterus. Fish abundance was high in May and June, and low in October and December, 2009. Chromis notatus was dominant at the all types of artificial reefs, Halichoeres poecilopterus for Gazebo type and Tetrapod type of artificial reefs, and Sebastes thompsoni for Dice type, Octagonal turtle type and Two-stage tube type of artificial reefs.

Sexual Maturity and Early Life History of the Mudskipper Scartelaos gigas (Pisces, Gobiidae): Implications for Conservation

Scartelaos gigas is an amphibious mudskipper species that inhabits mud flats in Korea, China, and Taiwan. This fish is at risk of extinction because of its very restricted habitat and overexploitation. Information about this fish’s reproductive characteristics is needed for species conservation. The sexual maturity and early life history of S. gigas were investigated through histological methods and direct observation of eggs in the wild, respectively. In total, 560 individuals of S. gigas were collected with the aid of fishermen from March 2003 to October 2003 at Jung-do Island, southwest Korea. Through microscopic observations of gonadal development, it was determined that S. gigas of both sexes were immature in April, but began to reach maturity in May, and were then fully mature by June, which was maintained until July. In August, some female fish developed early oocytes, but by September oocytes were observed to have degenerated and had been absorbed. Spawned eggs were elliptical and had an average size of 1.37 mm (long axis) by 0.69 mm (short axis). The newly hatched larvae (3.03 mm total length, TL) had an open mouth and anus, two melanophores near the anus, and one large melanophore between the 18th and 19th myomeres. The larvae (3.18 mm TL) showed absorption of the yolk and oil globule within 5 days after hatching and became prelarvae. This species should be considered vulnerable or conservation-dependent, and thus parental fish need to be protected from fishermen during the main spawning season (June).

Characteristics of lost fishing gear distribution on the sea bed around gillnet fishing ground for yellow croaker in the near sea of Jeju, Korea

T23= :+:/ /. 98 >2/ .3=> 398 +8. >2/ -97:9=3>398 90 69=> 03=2381 1/+ 2/ =/+ ,/.+ 2/ 8/+ 9 O->9,/ 937: 2/ 03=2/ . R/-9@/ 03=2381 1/+ >9>+6 10 >37/= A3>2 +> +6981 >2/ 3=9,+>2 . A= >2/ , 3> =//7= 9 -98-6?./ >2+> >2/ +79?8> 90 69=> 03=2381 1/+ 398 A3>2 >2/ .3: 90 >2/ =/+ ,/. += A/66 += >2/ 03=2381 1/+ 90 03=2381 1/+ =, . 3-?6+ /@/ 37/ A3>238 >2/ =? 03=2381 1/+ 2 , R/-9@/ 03=2381 1/+<=

Long-term variation in catch of Spanish mackerel (Scomberomorus niphonius) related to environmental change in Korean waters

),and oceanic condition in Korean waters were analyzed using 40 years of time-series data from 1971－2010.In the 1990s, oceanic conditions around the Korean peninsula shifted to awarmer regime with higher SST(sea surface temperature). The totalcatch of Spanish mackerelin Korean waters increased dramatically sincethe early 2000s, and main fishing ground form into South Sea in winter season from December to January.From the results of correlation analysis, we found asignificant relationship between the Spanish mackerelcatch and environmentalfactor such as SST , common mackereland anchovy catch in Korean waters.Keywords: Spanish mackerel, Korean waters, Catch, Increase, Oceanic conditions, Warmer regime

Acharacteristics on the forming of fishing ground and population ecological study of Yellow tail, Seriola quinqueradiata, in the coastal waters off Gim-nyeong of Jeju Island, Korea

, between Jeju Island and coastal areas of the East Sea is probably thesame. Water temperature probably is amajor factor for controlling distribution of yellowtails in deeper, off-shore areas off Jeju Island. However, the major factor that determines aggregation of yellowtails in coastalareas of Jeju Island, especially off Gim -nyeong is probably strong tidal currents driven by distribution ofyellowtails rather than hydrological conditions such as Yellowtails collected off Jeju Island were from 1 to4yrs old and about 50% of them were 1

Concentration of metallic elements in surface sediments at a waste disposal site in the Yellow Sea

Abstract The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 O 2 /g·dry, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.Key words: Ocean dumping, Metallic elements, Surface sediment, Yellow sea