First record of the percophidid fish <Emphasis Type="Italic">Osopsaron formosensis</Emphasis> (Percophidae: Hemerocoetinae) off Jeju Island,Korea

A specimen of Osopsaron formosensis was collected at the southeastern part of Jeju Island in June 2008. This specimen is to be distinguished from congeneric species using the key characters such as the eye with dorsal iris flap, cheek with scales, elongated dorsal spine, the length and the numbers of the first dorsal spines, and black pigmentation of the dorsal fin membrane. This report was the first record of O. formosensis from Korea. We named it ‘No-ran-tti-nun-tung-ii’ in Korean.     

An assemblage of mollusks associated with the high latitude scleractinian coral <Emphasis Type="Italic">Alveopora japonica</Emphasis> (Eguchi 1968) in Jeju Island,off the south coast of Korea

Corals reefs and communities support a wide range of flora and fauna. The complete richness and abundance of faunal communities in either coral reefs or communities is not fully understood. This is especially true for high-latitude coral communities. In this work, we carried out an analysis of an Alveopora japonica associated mollusk assemblage, in Jeju Island, Korea. A. japonica is one of the major coral species present in high abundance (88–155 colonies m^-2), with a high recruitment rate (7.8 juvenile corals m^-2 yr^-1) in Jeju Island, and may serve as a habitat for other benthic organisms. In 2012, a total number of 579 A. japonica colonies with sizes ranging between 15.1-346.7 cm² in the surface area were collected from a 1m× 10m quadrat installed at a depth of 10 m at Keumneung, on the northwest coast of Jeju Island. Numerous benthic invertebrates were found to be associated with A. japonica colonies. Twenty-seven bivalves and gastropods were identified, including a boring mytilid, Lithophaga curta, and an arcid, Barbatia stearnsi. A zonalgeographical examination of the distribution ranges of these mollusks revealed a majority of warmer water species. Our observations also showed that A. japonica may be providing a habitat to grazing gastropod, Turbo cornutus, and encrusting Spondylidae and Chamidae bivalves. A. japonica forms a coral carpet with a distinct assemblage of bivalves. It is thought that the presence of these mollusks species in the coral indicates its use as a nursery for juvenile species, a ready food supply of organic detritus, and a refuge from predators.     

The ecological importance of the dwarf seagrass <Emphasis Type="Italic">Zostera japonica</Emphasis> in intertidal areas on the southern coast of Korea

The intertidal seagrass Zostera japonica, which is distributed in the intertidal and shallow subtidal zones, is exposed to nutrients from over-enriched land-based discharge and storm water runoff before they can be washed out to sea. Despite its ecological importance, only a few studies have examined the ecology and physiology of Z. japonica in northeast Asia. In this study, we investigated the productivity and tissue nutrient contents of above- and below-ground tissues to evaluate the potential role of Z. japonica in carbon capture and as a nutrient sink. The average total, above-, and below-ground productivity per shoot was 0.56, 0.34, and 0.21 mg DW shoot^-1 day^-1, respectively. Annual leaf production was 1.5 times higher than annual below-ground production. Estimated annual whole-plant carbon, nitrogen, and phosphorus incorporation based on shoot production and tissue nutrient contents was 312.8 g C m^-2 y^-1, 25.7 g N m^-2 y^-1, and 1.6 g P m^-2 y^-1, respectively. These values were equivalent to 7.8 × 10³ kg C y^-1, 6.4 × 10² kg N y^-1, and 40 kg P y^-1 for all Z. japonica beds in Geoje Bay. This suggests that Z. japonica meadows can incorporate a considerable amount of carbon, nitrogen, and phosphorus in the intertidal zone. High N:P ratios of above- and below-ground tissues suggest that Z. japonica growth is probably limited by phosphorus availability in the study area.     

Long-term changes in rocky intertidal macrobenthos during the five years after the <Emphasis Type="Italic">Hebei Spirit</Emphasis> oil spill,Taean, Korea

The Hebei Spirit oil spill reached the west coast of Taean County, Korea, on December 7, 2007. At that time, this was the largest oil spill that had occurred in the country. The incident devastated local marine ecosystems. In this study, we examined changes in these ecosystems and the recovery pattern on impacted rocky shores. Macrobenthos monitoring of polluted and control sites was performed seasonally from January 2008 through October 2013. At polluted sites, ecological indices increased gradually from 2009, thereby providing evidence of recovery. However, the mean density of macrobenthos was still less than 50% of the level at the control site, indicating that the ecological status of the polluted sites has still not recovered to that which prevailed before the oil spill. Although densities of the most dominant species were higher in the control site than in polluted sites, the densities of Lottia spp. and Odostomia aomori were higher in polluted sites. These two taxa were found in lower numbers at the control site, where they were out-competed by Chthamalus challengeri. Nonmetric multidimensional scaling ordination divided the macrobenthic community structure into three clusters according to differences in the abundance of dominant species over the 6 years after the oil spill. An ANOSIM test detected significant differences between the polluted and control sites. Consistent long-term differences indicate that complete recovery had not occurred during the duration of our study.     

A new species of the genus <Emphasis Type="Italic">Ammonicera</Emphasis> (Prosobranchia,Omalogyridae) in a coralline algae community from Jeju Island,off the south coast of Korea

A species of the genus Ammonicera Vayssière, 1893 collected from coralline algae communities in Jeju Island, South Korea, is described as a new species, A. aurea, for science. Its morphological characters are described and illustrated by SEM micrographs. This new species can be clearly distinguished from other Ammonicera species from the Pacific Ocean by the presence of a spiral cord and about 25 slightly-elevated axial ribs, resulting in about 25 nodules at intersecting points of the cord and ribs on the last whorl of the teleoconch.     

Population dynamics of the solitary ascidian <Emphasis Type="Italic">Herdmania momus</Emphasis> (Savignyi, 1816) in Jeju Island,Korea

In 2007–2008, a population outbreak of the solitary ascidian Herdmania momus was observed along the coasts of Jeju Island and the ascidians became the top dominant species in macrobenthic communities. We conducted field experiments on population dynamics and demographic parameters including seasonal density fluctuation, vertical distribution, recruitment patterns, mortality, and growth rate. Recruitment continued year-round except in April following the lowest water temperature season in February. Population density was highest in August-October, concomitantly with the peak in recruitment, related to the highest water temperature. The lowest density was observed in February-April when the water temperature was lowest. In April all individuals disappeared from all permanent plots, resulting in a maximum life span of 10–12 months. Individuals of newly recruited H. momus grew to have an adult size of 4–6 cm in only 3–4 months. Higher densities were observed in the shallower areas (5 m) compared to the deeper zones. More recruitment occurred on vertical slopes than horizontal substrates, but substrate pre-occupancy caused no difference in recruitment. This is the first report on H. momus population-level investigation in Korea, which provides valuable baseline information on the current status of population demography and their potential community-level influence on Jeju coasts.     

Occurrence of Anisakid Nematodes in Walleye Pollock (<Emphasis Type="Italic">Gadus chalcogrammus</Emphasis>) Caught off the East Sea of Korea: Their Molecular Identification and Biological Implication

Walleye pollock (Gadus chalcogrammus) is one of the popular fish species in Korea and known to frequently harbor anisakid nematodes. Despite many papers regarding walleye pollock having been published, there is no information on the prevalence and distribution of anisakid nematodes from walleye pollock in Korean waters. We investigated 716 walleye pollock caught from Goseong, the East Sea of the Korean Peninsula during May 2015–December 2016. In total, 1,085 nematodes were collected and subsequently identified by PCR-RFLP analysis of internal transcribed spacer region of ribosomal DNA. The prevalence and mean intensity of anisakid nematodes was 63.6% (68/107) and 4.4 larvae/fish (297/68) in samples of 2015, and 21.5% (131/609) and 6.0 larvae/fish (788/131) in samples of 2016. The most abundantly isolated anisakid nematode was Anisakis simplex (Rudolphi, 1809) (73.5%, 798/1,085), followed by Contracaecum osculatum (Rudolphi, 1802) (3.1%, 34/1,085), Hysterothylacium aduncum (Rudolphi, 1802) (2.9%, 31/1,085), Anisakis pegreffii (Campana-Rouget and Biocca, 1955) (1.4%, 15/1,085), and a hybrid genotype (0.4%, 4/ 1,085). The mitochondrial DNA cox2 gene sequences of randomly selected A. simplex showed the highest similarity (99.5%–98.8%) with those from chub mackerel (Scomber japonicus) in Japan or from chum salmon (Oncorhynchus keta) in Korea. The mtDNA cox2 gene sequences of C. osculatum showed the highest similarity (99.0%) with those from bearded seals in Japan. All of these results give us clues to the geographical distribution, migration route and prey items of walleye pollock caught off Korea. Further extensive analyses will be necessary to get more information on the biology of Korean walleye pollock.     

Growth and reproduction of the Japanese mantis shrimp, <Emphasis Type="Italic">Oratosquilla oratoria</Emphasis> (De Haan 1844) in the coastal area of Tongyeong,Korea

Growth and reproduction of the Japanese mantis shrimp, Oratosquilla oratoria, were investigated in the Tongyeong, Korea from July 2014 to August 2015. A total of 2,621 samples (1,380 females and 1,241 males) were collected during the study period. Females were observed more frequently than males. The mean body length (BL) was 128.5 ± 0.38 mm in females and 126.9 ± 0.42 mm in males. The mean body weight (BW) was 31.2 ± 0.28 g in females and 31.1 ± 0.32 g in males. There was a significant difference in the length-frequency distribution between females and males. The relationship between BL and BW was lnBW = 2.85 × lnBL - 10.43 for females and lnBW = 2.87 × lnBL -10.52 for males. The gonadosomatic index (GSI) varied on a monthly basis. The GSI reached a maximum in May and a minimum in November. The highest values of the GSI coincided with the spawning period of O. oratoria. Larger individuals of O. oratoria have their spawning season earlier than smaller ones. The size at sexual maturity of females was estimated as 96.5 mm. The Von Bertalanffy growth function parameters were BL_∞ = 184.5 mm, K = 0.72 year^?1, C = 0.36 and WP = 0.45 for females and BL_∞ = 183.75 mm, K = 0.82 year^?1, C = 0.38 and WP = 0.22 for males. The growth of males was slightly faster than females. The present study will help with the fisheries management of O. oratoria based on ecological parameters.