Kyum Joon Park

Accumulation of butyltin compounds in finless porpoises (Neophocaena asiaeorientalis) from Korean coast: tracking the effectiveness of TBT regulation over time.

The concentrations of butyltin compounds (BTs) were measured in the livers of finless porpoises (Neophocaena asiaeorientalis) caught off the Korean coast in 2003 and 2010, to assess the effectiveness of legislative action against BTs. The concentrations of BTs ranged from 65.1 to 1432 (average: 370) ng/g wet weight, within the ranges reported by previous studies. The levels of BTs in almost all the samples exceeded the suggested threshold value, implying potential adverse health effects from the BT exposures. Concentrations of BTs were significantly correlated with body length, weight, and age of finless porpoises, but were not correlated with sex. Spatial differences in the concentrations of BTs were not observed between Yellow and South Seas, while there was a significant decrease in BTs between the sampling years of 2003 and 2010. Our result indicates that the effectiveness on TBT ban has reached to marine mammals in the coastal waters of Korea.

Occurrence and accumulation features of polycyclic aromatic hydrocarbons and synthetic musk compounds in finless porpoises (Neophocaena phocaenoides) from Korean coastal waters.

Reports of the occurrence and accumulation patterns of polycyclic aromatic hydrocarbons (PAHs) and synthetic musk compounds (SMCs) in marine mammals are scarce. In this study, the concentrations and accumulation profiles of PAHs and SMCs were determined in blubber from finless porpoises in Korean coastal waters. Total concentrations of PAHs and SMCs ranged from 6.0 to 432 (mean: 160) ng/g lipid weight and from 17 to 144 (mean: 52) ng/g lipid weight, respectively. Residue levels of PAHs were lower than those reported from other studies, while residue levels of SMCs were relatively higher than those reported in other studies. Naphthalene was the most abundant PAH and HHCB was the dominant SMC observed in finless porpoises. The concentrations of PAHs and SMCs were not correlated with each other, but were significantly correlated within the same chemical groups. No correlations were found between body size and residue levels of PAHs and SMCs.

Contamination status and accumulation features of PCDDs, PCDFs and dioxin-like PCBs in finless porpoises (Neophocaena phocaenoides) from Korean coastal waters

Data on the concentrations and accumulation profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in cetaceans are scarce. In this study, concentrations and accumulation profiles of PCDD/Fs and DL-PCBs were measured in the blubber of finless porpoises (Neophocaena phocaenoides) collected from Korean coastal waters. Total dioxin-like toxic equivalent (TEQ) concentrations (6.5-31 pg/g lipid weight) in finless porpoises were lower than those reported for cetaceans and pinnipeds from other countries. Significant gender-specific differences were found in the concentrations and accumulation profiles of PCDD/Fs and DL-PCBs and this difference was associated with maternal and lactation transfer of contaminants from mature females to their fetus. All of the PCDD/F homologue groups were detected in all of the samples and the proportions of PCDFs were higher than those of PCDDs. The dominant congeners found in finless porpoise blubber were 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF and OCDD for PCDD/Fs and PCB 118 for DL-PCBs. The accumulation profiles of PCDD/Fs in finless porpoise in our study were different from those found for cetaceans from other countries. Total TEQ levels in finless porpoises in Korea were below the suggested threshold values for adverse health effects in marine mammals.

Age and reproduction of the finless porpoises, Neophocaena asiaeorientalis, in the Yellow Sea, Korea

A total of 116 finless porpoises, Neophocaena asiaeorientalis, were collected in the Yellow Sea off Korea. About 111 specimens were incidentally caught by stow nets on anchors from March to June 2010, and five were stranded in February 2011. Age was determined by counting dentinal growth layer groups (GLGs) in thin-sectioned teeth, and sexual maturity rating (SMR) was classified by investigating ovaries and testis macroscopically and microscopically. Immature females were ranged 1–4 years old and 92.6–141.2 cm in total body length (TBL), pubertal ones were all 5 years old and 125.4–136.0 cm, and mature ones ranged 5–19 years old and 131.6–155.2 cm. Age at attainment of sexual maturity of females was 4–5 years old. Parturition season estimated based on TBL of eight fetuses was from April to August with a peak in April to May. The first age at parturition was 5 years old. Among 62 males, immature males were 1–4 years old and 87.9–154.6 cm, pubertal ones were 3–5 years old and 121.5–134.5 cm, and mature ones were 4–19 years old and 125.3–229.0 cm. Males reached sexual maturity at 4–5 years old. Testicular mass and the diameters of seminiferous tubules were dramatically increased with SMR and regressed in testis of the individuals stranded in February. It suggested that male finless porpoises have aspermatogenic period between October and February. It is presumed that the breeding season would be May–September with a peak in May–June.

Distribution of Whales and Dolphins in Korean Waters Based on a Sighting Survey from 2000 to 2010

In the late 1970s, the National Fisheries Research & Development Institute (NFRDI) started cetacean research to submit the Korean whale catch record to the International Whaling Commission. This continued until the moratorium on commercial whaling in 1986. The NFRDI resumed cetacean research with a pilot whale sighting survey in 1999. Subsequently, the NFRDI has conducted 53 cetacean sighting surveys within the Korean exclusive economic zone between 2000 and 2010. The surveys took a total of 760 days and cruising for 23,866 nautical miles. The finless porpoise Neophocaena asiaeorientalis was sighted most frequently (735 times), followed by the minke whale Balaenoptera acutorostrata (396 times), the long-beaked common dolphin Delphinus capensis (102 times), and the Pacific white-sided dolphin Lagenorhynchus obliquidens (27 times). Minke whales were distributed in the Yellow Sea and coastal area of the East Sea from spring to fall. Pacific white-sided dolphin sightings were restricted to the middle and upper coastal areas of the East Sea in summer. Common dolphins were sighted from east of the southern coast to the eastern coast of the Korean Peninsula from spring to fall. Finless porpoise occurred in all Korean coastal areas, except the middle and upper eastern coast.

Determination of the haplotype and complete mitochondrial genome of the leatherback turtle Dermochelys coriacea (Testudines: Dermochelyidae) found in the vicinity of Korea

Although several strandings of the leatherback turtle (Dermochelys coriacea Vandelli, 1761) have been reported in Korea, its haplotype or mitogenome have yet to be investigated. Herein, we report the first complete mitogenome of D. coriacea. The 16,501-bp sequenced mitogenome is similar to those of other marine turtles, and the particular genetic features reported in birds and turtles were also found in ND3 and ATP8. The comparison of the control region verified that D. coriacea stranded in Korea belonged to the haplotype JD1 (identical to haplotypes I and Dc9.1). Multigene phylogeny revealed that D. coriacea was well separated from other Cheloniidae species, and the overall tree topology was congruent with the recent phylogenetic analysis of marine turtles. These results provide information fundamental for genetic and conservation studies on leatherbacks, especially the critically endangered West Pacific Ocean subpopulation.

A New Abundance Estimate for the Finless Porpoise Neophocaena asiaeorientalis on the West Coast of Korea: An Indication of Population Decline

The west coast of Korea is the largest habitat for finless porpoises, with approximately 36,000 individuals reported in 2005 (Park et al., 2007). To date, there have been no subsequent finless porpoise population estimates. However, in recent bycatches, finless porpoises accounted for the highest proportion of all cetaceans and have been reported to be most frequently caught on the west coast of Korea (Kim et al., 2013). The present study, conducted in 2011, enumerated finless porpoises inhabiting the west coast of Korea using a line transect survey in offshore and inshore regions to assess variations in their abundance. In offshore regions we found the population density of finless porpoises to be 0.122 ind./km 2 , whereas it was 0.565 ind./km 2 in 2004. In inshore regions, the population density of finless porpoises was 0.151 ind./km 2 , whereas it was 0.638 ind./km 2 in 2005. Therefore, we estimate that the population densities of finless porpoises in both offshore and inshore regions of the west coast of Korea decreased by ap proximately 70% between 2004/2005 and 2011. It is imperative to mitigate the bycatch of finless porpoises and protective action is urgently needed in the near inshore regions.

Occurrence of Indo-Pacific Bottlenose Dolphins Tursiops aduncus off Jeju Island, Korea during the Early 2000s

【The Indo-Pacific bottlenose dolphin Tursiops aduncus commonly inhabits the coastal waters of Jeju Island, Korea. An investigation was conducted using data from vessel sightings and point sightings from land. During 40 days of vessel sighting surveys between 2007 and 2010, a total of 18 dolphin groups were encountered. The overall sighting rate was 0.01 group/n.m. Most Indo-Pacific bottlenose dolphins were sighted within 500 m of the northern coast of Jeju Island during surveys. Also, dolphin groups were observed 47 times during 109 days of shore-based surveys conducted between 2011 and 2015. The results of a dolphin distribution survey conducted in 2011 were generally similar to the results of previous surveys. However, there were no dolphin sightings from 2012 in Hanllim-eup, in the north-western part of the island, where dolphins were sighted frequently until 2011, whereas dolphin observations increased in the southern part of the island. The mean group size was 35.4 (SD=18.08) individuals. The most frequently sighted group size was 36-40 individuals. To conserve resident dolphins off Jeju Island, long term sighting surveys and environmental assessment are required to monitor their distribution patterns.】

Seabird Distribution Patterns by Strip Transect in the Yellow Sea in Spring

바닷새는 연안역이나 외해, 혹은 대양에서 먹이를 취하는 조 류로(Harrison, 1983), 해양생태계의 상위포식자 역할을 하며 다양한 종류의 어류 및 두족류, 난바다곤쟁이와 같은 대형 동물 성플랑크톤을 주로 섭이한다(Gaston, 2004). 전 세계 바닷새가 일 년간 필요로 하는 먹이양은 7천만에서 1억 톤 가량으로 추 정되며(Brooke, 2004) 이는 전 세계 수산물 연간 어획량인 약 9천만 톤(FAO, 2014)에 상당하는 양이다. 바닷새의 먹이는 어 업 대상종과 중복되거나, 섭이장이 조업 구역과 겹치는 경우가 많아 바닷새와 어업 활동 사이에서의 경쟁이 빈번하게 발생하 고(Montevecchi, 2002; Karpouzi et al., 2007) 어구에 의한 혼 획으로 개체수가 감소하기도 하는 등(Žydelis et al., 2009; Anderson et al., 2011) 바닷새와 수산업은 상호 영향을 받고 있다. 서해 국내 수역에는 약 339종의 어류, 135종의 연체류, 148 종의 절지류 등이 발견된다(Lee, 2004; Lee, 2014). 서해 연안 은 수심이 얕고 내만이 발달하여 주요 유용어종들의 산란장 및 보육장 역할을 하므로 그 가치가 매우 크다(Hao et al., 2003; Hwang et al., 2006). 서해 연안의 무인도서인 칠발도, 난도, 구 굴도 등은 다양한 종류의 바닷새 번식장으로 이용되며(Lee, 1989; Lee et al., 2002; Kang et al., 2008) 인근 해역에서 먹이 사냥을 하므로 생태적으로 매우 중요한 가치를 인정받아 이들 무인도서는 천연기념물로 지정·보호받고 있다. 바닷새는 해양포유류나 어류 등 다른 해양동물보다 해상에 서 관찰이 용이한 특성으로 인해 개체수의 증감이나 분포 변 화 연구를 통하여 해양생태계의 변동에 대한 효과적인 지시자 (indicator)로서 여러 해역을 대상으로 다양한 방법의 조사가 이루어지고 있다(Fauchald and Erikstad, 2002; Davoren and Montevecchi, 2003; Parsons et al., 2008). 특히 최근에는 바닷 새의 개체수, 먹이조성, 건강상태, 번식 성공률 등을 지표로 삼 아 생태계 기반 어업 관리를 하고자 하는 연구가 활발하게 진행 되고 있다(Einoder, 2009). 국내에서도 생태계 기반 어업 관리를 위한 기초적인 연구로서 연안 생태계의 구조를 파악하고, 생태계를 구성하고 있는 각 생 물종 및 생물군의 영양역학적인 관계를 밝히려는 노력이 시도 되고 있으나(Zhang and Yoon, 2003; Lee, 2014) 해양생태계의 한 축을 담당하고 있는 바닷새의 분포 현황이나 생체량 등의 자 료가 부족하거나 전무한 실정이다. 지금까지 서해에서의 바닷새 연구는 무인도서를 중심으로 번 식생태 연구가 주를 이루어왔다(Lee, 1989; Kang et al., 2008). 직선횡단조사에 의한 서해 연안 봄철 바닷새의 분포 양상

Diet of long-beaked common dolphin (Delphinus capensis) in the East Sea, Korea

The long-beaked common dolphin is one of the most abundant cetaceans in Korean waters, and their population has been estimated to comprise of more than 35,000 individuals. Delphinus capensis generally appear close to the coast and primarily feed on epipelagic small fishes and cephalopods. Thirty long-beaked common dolphins were collected from the East Sea from February to September in 2012. For stomach content analysis (SCA), the fresh prey items were identified to their lowest taxonomic level, and unidentified preys due to digestion were identified using remnants such as fish otoliths and cephalopod beaks. Fatty acid (FA) patterns of 20 dolphins from the inner layer of blubber were compared with those in samples of prey items. Enoploteuthis chunii was the dominant prey in SCA, representing 55.8% by number and 75.9% by occurrence. Common squid (Todarodes pacificus) and Pacific herring (Clupea pallasii) were the next major preys at more than 80% occurrence. Even though a distinctive difference was not observed between genders, there was a significant diet variation related to maturity. Immature dolphins consumed a higher diversity of prey, and consumed more equally than the sexually mature group, who showed a high dominance of cephalopods. Furthermore, this result fairly corresponded to FAs composition of mature dolphins with the raised percent of 20:6n–3, which is relatively abundant in T. pacificus.