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One specimen (38.3 mm SL) of Neoclinus lacunicola Fukao, 1980, belonging to the family Chaenopsidae, was first recorded from Ulleung Island, Korea (East Sea, otherwise known as the Sea of Japan) on 5 January 2021. This species was characterized by paired external pores of incomplete lateral line running from the upper margin of the opercle, seven pairs of supraorbital cirri arranged in two rows, occipital region with a pair of cirri, and 13 rays of pectoral fin. This species is morphologically similar to the Neoclinus toshimaensis Fukao, 1980, but differs in the number of cirri on the supraorbital (6–7 versus 9–11 cirri). This study documents the first report of N. lacunicola in Korean waters and proposes the new Korean name of ‘eol-lug-bi-neul-be-do-la-chi’ for the species. For the confirmation of the identity of the species, a partial gene sequence of the mt COI (570 bp) of N. lacunicola was obtained for the first time.

This study reports the first data on length–weight (LWR) and length-length (LLR) relationships, and seasonal body condition factors of Blueline snapper, Lutjanus coeruleolineatus (Ruppell, 1838) inhabiting Salalah Coast, Sultanate of Oman. The regression slopes of LWRs were significantly different between immature and mature groups, and among different seasons, but it was not significant between male and female specimens. The relationships between total and standard length, between standard and fork length, and between fork and total length were linear (r2 > 0.972) regardless of sex. The body condition of fish was significantly higher during the southwest monsoon (both pre- and post-monsoon) than during the non-monsoon seasons. The results from this study contribute to understand biology of L. coeruleolineatus and are useful data for the development of conservation and management plans of this species.

The blueline snapper, Lutjanus coeruleolineatus (Rüppell, 1838), is a significant commercial fish species harvested from the traditional fishery in the Sultanate of Oman. Deficient data on this species, however, make the management strategies challenging, especially in fisheries ecology. A total of 978 specimens were obtained from Dhofar Governorate off the coast of the Arabian Sea during the period between February 2015 and March 2016. In total, 296 sectioned otoliths were analyzed and growth was estimated from non-seasonal growth by using von Bertalanffy method. The parameters of von Bertalanffy growth function, total mortality (Z), natural mortality (M), fishing mortality (F), and exploitation rate (E) were determined and compared with those for Lutjanidae fishes elsewhere. The age structure of male fishes was between 1 and 14 years for males while the age of females ranged from 1 to 18 years. Growth rate (K) was 0.21 y–1 and 0.16 y–1 for males and females, respectively. The hypothetical length of female (L∞ = 46 cm) was relatively higher than that of male (L∞ = 42 cm). The natural mortality (M) was 0.296, total mortality (Z) was 0.372, fishing mortality was 0.076, and exploitation rate (E) was estimated as 0.2. The presently reported study is conducted to examine this fish in relation to growth parameters by analyzing otolith structure. The results of the presently reported study will contribute towards planning the regional fishery management policies in Oman.

Dietary habits and inter-specific differences in resource use among six commercial fish species, Chelidonichthys spinosus, Cleisthenes pinetorum, Glyptocephalus stelleri, Hexagrammos otakii, Lophius litulon, and Sebastes schlegelii, collected from the southern coast of the East Sea, Korea, were analyzed using stomach content and stable isotope analyses. Teleosts were the main prey items for C. pinetorum and L. litulon, while both crabs and teleosts contributed to the diets of C. spinosus and S. schlegelii. Glyptocephalus stelleri mainly consumed polycheates and carid shrimps, and H. otakii mostly ingested crabs. The composition of prey items was significantly different in the diets of the six fish species. Further, carbon (δ13C) and nitrogen (δ15N) stable isotope values were significantly different among the six species, indicating different trophic positions. L. litulon, C. pinetorum, and S. schlegelii had narrow niches, whereas C. spinosus, G. stelleri, and H. otakii had relatively wider niches. This study demonstrated differences in patterns of food resource use among the six fish species that were categorized into two patterns of resource use according to their main prey items: diet diversity, trophic niche width, and trophic position. These results could contribute to the understanding of trophic relationships among fish species inhabiting the East Sea, Korea.

Patterns of mother-embryo fractionation of

Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal and/or trophic strategies. Fishes living in the intertidal zone demonstrate highly adaptive plastic behaviour, including resource partitioning, through spatial and temporal shifts in diet and microhabitat. Although intertidal fish assemblages are influenced by inter- and intraspecific competition, few studies have compared the extent of resource partitioning between sympatric species in the context of trophic niche plasticity. Here we used complementary approaches, stomach content and stable isotope (δ13 C and δ15 N) analyses, to evaluate seasonal and developmental shifts in trophic niche position in two sympatric (Favonigobius lentiginosus and Bathygobius krefftii) and one allopatric (Bathygobius cocosensis) species of intertidal goby. The results indicate that resource partitioning in the two sympatric species varied with season, with almost no trophic niche overlap in summer to about ~30% overlap in winter. Also, evidence of dietary changes was found in B. cocosensis, which is likely associated with a shift in microhabitat and intraspecific competition. The findings highlight the temporal range of behavioural plasticity in trophic niche position of intertidal gobies, which likely has high adaptive value in the dynamic intertidal zone.

Diets and feeding patterns of brown croaker, Miichthys miiuy were studied using 293 specimens collected from the coastal waters of south-western Korea. Total length (TL) of these specimens ranged from 30.7 to 84.8 cm. Miichthys miiuy was a piscivore that primarily consumed teleosts. They also ate crustacean decapods including caridean shrimps, prawns and crabs. Multivariate analyses of dietary data revealed that the diets of M. miiuy were significantly associated with TL, maturity, and month, but not influenced by season or sex. Although teleosts were dominant in the diets of all sizes, decapods also contributed substantially to the diets of smaller individuals. In terms of month, a little change was observed among months. A graphical method of feeding pattern revealed that M. miiuy was a specialized predator, consuming mainly teleosts from both immature and mature groups. Taken together, stomach content analysis in this study indicated that fish size is the most important indicator on dietary changes of M. miiuy inhabiting south-western waters off Korea.

Diel and gastrointestinal changes in relation to the feeding intensity and prey composition of Apogon lineatus were investigated through the analysis of the diet contents of 174 fishes collected from the southeastern coast of Korea. Fish samples were collected at both day and night times during winter using a small bottom trawl. Stomach fullness, stomach contents index (SCI) and intestine contents index (ICI) of A. lineatus varied with day-night changes. Multivariate analyses revealed that dietary contents differed significantly between the stomach and intestine, but were similar between day and night in both stomachs and intestines. In the stomachs, prey items mostly consisted of caridean shrimps and euphausiids, while the relative contributions of amphipods and unidentifiable items tended to be high in the intestine contents, indicating that the intestines mainly contained content made up of nearly digested and/or hard shell items.

Recent global climate change often leads to poleward expansions of habitat range of marine organisms in response to increasing water temperature at high latitude. This study investigated latitudinal distribution patterns of Turbo sazae from 2009 to 2018 along the southern and eastern coasts of Korea to verify whether gradual increases in seawater temperature in the East Sea/Sea of Japan (hereafter East/Japan Sea) accelerate changes in the geographic distribution of T. sazae. Between 2009 and 2018, underwater SCUBA surveys were conducted at 19 subtidal rocky shore habitats from the southern and eastern coast of the Korean Peninsula, including Jeju Island. Additionally, long-term seawater temperature records over the last 40 years (between 1980s and 2010s) from the East/Japan Sea were analyzed to verify how changes of water temperature corresponded to geographical distributions of T. sazae. The habitat range of T. sazae was found to have extended from latitude 34&deg, 02&prime, N to latitude 37&deg, 06&prime, N from 2009 to 2018. Although seawater temperature has gradually increased since the 1990s in the East/Japan Sea, habitat expansion was particularly evident during the rapid rise of coastal seawater temperature in the 2010s. Because the strong northward expansion of the Tsushima Current can accelerate the rise of seawater temperature in the East/Japan Sea, studies of the effects of climate change on marine ecosystems of the Korean Peninsula should include data from monitoring the dynamics of the Tsushima Current.

Variabilities of biological communities in lower reaches of urban river systems are highly influenced by artificial constructions, alterations of flow regimes and episodic weather events. Impacts of estuary weirs on fish assemblages are particularly distinct because the weirs are disturbed in linking between freshwater and estuarine fish communities, and migration successes for regional fish fauna. This study conducted fish sampling at the lower reaches of the Nakdong River to assess spatio-temporal variations in fish assemblages, and effects of estuary weir on structuring fish assemblage between freshwater and estuary habitats. In total, 20,386 specimens comprising 78 species and 41 families were collected. The numerical dominant fish species were Tachysurus nitidus (48.8% in total abundance), Hemibarbus labeo (10.7%) and Chanodichthys erythropterus (3.6%) in the freshwater region, and Engraulis japonicus (10.0%), Nuchequula nuchalis (7.7%) and Clupea pallasii (5.2%) in the estuarine site. The fish sampled were primarily small species or the juveniles of larger species at the estuary region, while all life stages of fishes were observed at the freshwater habitats. The diversity patterns of fish assemblages varied greatly according to study site and season, with higher trends at estuarine sites during the warm-rainy season. No significant difference in diversity between freshwater and estuarine sites during the cold-dry season were found. Multivariate analyses of fish assemblage showed spatial and seasonal differences of assemblage structures. Higher effects of between-site variability but not within seasonal variability at each site were observed. Variations in assemblage structures were due to different contributions of dominant species in each habitat. Common freshwater species characterized the fish assemblage in the freshwater region, while marine juveniles were significantly associated with the estuarine habitat. The results from the ecological guild analyses showed distinct ecological roles for freshwater and marine species, and overlapping roles for fish sampled at the fishways. The lower reaches of the Nakdong River are an important ecosystem for both freshwater and marine juveniles. Nakdong River estuarine residents and migrant fishes, however, have been negatively affected by the construction of the weir (gravity dam), due to the obstruction to migration from and to freshwater habitats. Conservation and management policies aimed at minimizing anthropogenic influences on estuary ecosystems should focus on evaluating ecological functions of estuary weirs.

Decapod assemblages in Zostera marina beds from two bays adjacent to unvegetated habitats were investigated to assess their influence on decapod assemblages. Thirty-eight decapod species belonging to four taxa were collected using a small beam trawl at four habitat types from two different locations off the coast of Namhae Island, South Korea. Dominant decapod taxon at all habitats was the caridean shrimps, with Eualus leptognathus, Heptacarpus pandaloides, Latreutes anoplonyx, La. Laminirostris, and Palaemon macrodactylus being the most abundant caridean species. Crabs were characterized with the highest biomass, but with moderate species richness and abundance. Penaeoid and sergestoid shrimps only accounted for &lt, 1% of the total decapod abundance. The number of species and their abundance of decapod assemblages varied greatly by habitat type, season, and diel patterns, but not diversity. Species number and abundance peaked in seagrass beds of southern exposed bays during the autumn and were lowest in unvegetated habitats during the summer months. Diel decapod catch rates were higher at night. Dense seagrass vegetation and nighttime supported higher decapod mean densities, but not species richness and diversity. Multivariate analyses revealed that habitat type and season significantly affected the structure of decapod assemblages, but diel patterns had a minor influence. Among decapod species, Pa. macrodactylus and Pugettia quadridens characterized the decapod assemblages in seagrass beds at the northern semi-closed bay, while Telmessus acutidens, Crangon affinis, Cr. hakodatei, Charybdis (Charybdis) japonica, and Portunus sanguinolentus were significantly associated with both vegetated and unvegetated habitats at the southern exposed bay, with the former two species more abundant during the colder season.

Seagrass habitats are highly productive areas that support vegetative habitats and provide shelter for various marine animals. In seagrass beds, vegetation patterns are important factors that control faunal assemblage structure. In this study, we surveyed fish assemblage structures in Zostera marina beds and in adjacent unvegetated habitats to assess the influences of seagrass vegetation and biomass on fish assemblage structures. In total, fifty-four fish species belonging to 30 families were collected using a small beam trawl at both seagrass beds and unvegetated habitats from two different areas off the coast of Namhae Island, South Korea. The dominant fish species in seagrass beds were Sebastes inermis and Rudarius ercodes, whereas Acanthogobius flavimanus and Takifugu niphobles were the most abundant fish species in unvegetated habitats. The number of species, their abundance, and the diversity of fish assemblages varied greatly by habitat type, study site, and season. Abundance peaked in seagrass beds and during the spring, and were lowest catch rate in unvegetated habitats and during the winter months. Multivariate analyses revealed that habitat type, site, and season affected the structure of fish assemblages. Seagrass vegetation supported higher densities and greater fish species richness, but not species diversity. Among the dominant species, Lateolabrax japonicus, Sebastes schlegelii, Syngnathus schlegeli, and Rudarius ercodes characterized the fish assemblages in seagrass beds, with the former two more abundant under conditions of higher seagrass biomass. Gobiid species were significantly correlated with unvegetated habitats.

Decapod assemblages in Zostera marina beds from two bays adjacent to unvegetated habitats were investigated to assess their influence on decapod assemblages. Thirty-eight decapod species belonging to 4 taxa were collected using a small beam trawl at four habitat types from two different locations off the coast of Namhae Island, southern Korea. Dominant decapod taxon at all habitats was the caridean shrimps, with Eualus leptognathus, Heptacarpus pandaloides, Latreutes anoplonyx, La. laminirostris and Palaemon macrodactylus being the most abundant caridean species. Crabs were characterized by the highest biomass, but moderate species richness and abundance. Penaeoids and sergestoids shrimps only accounted for

Choi, H.C.; Youn, S.H.; Huh, S.-H., and Park, J.M., 2018. Diet composition and feeding habits of two engraulid fish larvae (Engraulis japonicus and Coilia nasus) in the Nakdong River estuary, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 346–350. Coconut Creek (Florida), ISSN 0749-0208.Engraulis japonicus and Coilia nasus are members of the family Engraulidae, and their larvae are important components in the estuarian ecosystems that they inhabit. The dietary study of fish larvae is essential to understanding early survival and recruitment in fish populations. This study investigated the dietary compositions and size-related dietary changes in E. japonicus and C. nasus larvae in the Nakdong River estuary. Larvae samples were collected monthly between April and August 2011 using an RN80 net at two stations in the estuary. Gut content analyses revealed that E. japonicus fed mostly on copepods, and secondarily on tintinnids and cladocerans, while C. nasus preferred to consume freshwater cladocerans. These dietary differences between the two larvae were closely related with habitat preference, which provided different local prey sources at each station. As the larvae of both species grew, the consumption of copepods for E. japonicus, and cladocerans for C. nasus, gradually increased, indicating distinct ontogenetic dietary changes. This dietary study of larval E. japonicus and C. nasus is important information for the development of fisheries, and can be implemented in related further studies of areas other than estuaries.

Kim, M.J.; Kim, H.C.; Lee, W.C.; Park, J.M.; Kwak, S.N.; Oh, Y.; Kang, M.G., and Lee, S.H., 2018. Ecological characteristics of the new recorded seahorse in Geoje-Hansan Bay, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 351–355. Coconut Creek (Florida), ISSN 0749-0208. A basic ecological research of the seahorse populations has not been done to date even though the population is declining due to overfishing, by-catching and heavy human activities. Recently reported seahorse (Hippocampus haema) samples were monthly collected in Geoje–Hansan bay for a year from August 2015 to August 2016. Standard length (SL), weight (Wt), coronet height (CH), trunk length (TrL), and tail length (TaL) of each individual were measured for identifying characteristics of H. haema. The ranges of temperature and salinity were 8.2–26.0 °C and 29.3–34.1 ‰, respective...

Crustacean decapod assemblages were surveyed inZostera marinabeds adjacent to tidal flats (ET) and rocky shore (ER), and in unvegetated habitats (UV). Decapod samples were collected monthly throughout 2002 using a small beam trawl from northern Jinhae Bay, Korea. Water temperature, salinity, eelgrass biomass, sediment composition and organic matter were also monitored to assess any correlation between environmental variables and decapod fauna. A total of 31 decapod species belonging to five taxa (three prawns, 13 caridean shrimps, one hermit crab, one mud shrimp and 13 crabs) were collected at three different habitats. To assess variations in decapod assemblages in relation to habitat type and season, various multivariate analyses were used. The dominant caridean shrimps werePalaemon macrodactylus, Alpheus digitalisandCrangon uritai,and the dominant crabs wereCharybdis japonica, Hemigrapsus penicillatusandCharybdis bimaculata. The number, abundance and diversity of decapod species varied greatly with habitat type and season, peaking in eelgrass beds and during spring, and showing the lowest catch rate in unvegetated habitat and during winter months. The nMDS ordination and multivariate analyses revealed that habitat type and season were determinant factors affecting the structure of decapod assemblages. Seasonal shifts in the abundance of decapods corresponded with changes in eelgrass biomass and loss on ignition (LOI), but not with water temperature or salinity.

We conducted dietary analyses of six seagrass-associated fish species inhabiting northeastern Gwangyang Bay, Korea. These six species consumed a variety of benthic invertebrates and teleosts, but their preferences for different food resources varied. Although all species consumed crustaceans, the contributions of different crustacean taxa differed among the species’ diets. Caridean shrimps and crabs were a significant part of the Hexagrammos agrammus and H. otakii diets, respectively, while amphipods were consumed mainly by Sebastes inermis. Caridean shrimps and prawns were abundant within the Lateolabrax japonicas diet, but were not common prey resources for Pseudopleuronectes yokohamae or S. schlegelii. Polychaetes and ophiurids were ingested by P. yokohamae, and the former prey taxon also made moderate contributions to the diets of H. agrammus and L. japonicus. With the exception of P. yokohamae, the diets of all species included teleosts. Teleosts contributed the largest proportion of the S. schlegelii diet, followed by the S. inermis and L. japonicas diets; however, H. agrammus and H. otakii rarely consumed teleosts. Non-metric multidimensional scaling (nMDS) ordination plots and permutational analysis of variance (PERMANOVA) revealed the variation in dietary composition among species and the contributions of each prey taxon. These interspecific differences in diet increase the range of food resources available to these fishes, thereby reducing competition for resources within the fish community in this region.

This study examined the dietary patterns of walleye pollock, Gadus chalcogrammus, off the middle eastern coast of Korea between January 2016 and December 2017 to determine the influences of various predictors on dietary changes. Based on stomach content analyses, walleye pollock was found to be a demersal carnivore that mainly consumes carid shrimps, euphausiids, mysids, teleosts, and cephalopods. The main prey species identified in the diets of walleye pollock were Euphausia pacifica (euphausiids), Themisto japonicus (amphipods), Neomysis spp. (mysids), Neocrangon communis, Pandalus borealis (carid shrimps), Watasenia scintillans (cephalopods), and Bothrocara hollandi (teleosts), which are hyper-benthic and bentho-pelagic organisms. Dietary analyses based on the weight contributions of different prey taxa to the diets revealed significant variations in dietary composition in terms of fish size, water depth, and season, implying intraspecific dietary segregation. Euphausiids dominate the diets of smaller individuals (&lt, 30 cm TL), whereas the contributions of carid shrimps, teleosts, and cephalopods increase as body size increases. Similarly, the latter three prey items are dominant food resources in deeper habitats. The PERMANOVA results revealed that the size-related spatial and temporal changes in dietary composition are all significant for the species, as well as their two- or three-way interactions among those factors, except for the size-depth interaction. The coupling effect of size and depth is indicative of depth-dependent differences in fish sizes, with the tendency for larger individuals to be distributed in deeper habitats. In addition, seasonal and interannual variations in water column structures are also evident in the diets, which may, in part, account for the diet seasonality observed in the stomach content analysis. The dietary analyses of walleye pollock will improve our understandings to seek functional role of the species in benthic food webs, and to predict the effects of environmental and anthropogenic perturbations.

Potential roles of the rostrum of sawsharks (Pristiophoridae), including predation and self-defence, were assessed through a variety of inferential methods. Comparison of microwear on the surface of the rostral teeth of sawsharks and sawfishes (Pristidae) show that microwear patterns are alike and suggest that the elongate rostra in these two elasmobranch families are used for a similar purpose (predation). Raman spectroscopy indicates that the rostral teeth of both sawsharks and sawfishes are composed of hydroxyapatite, but differ in their collagen content. Sawfishes possess collagen throughout their rostral teeth whereas collagen is present only in the centre of the rostral teeth of sawsharks, which may relate to differences in ecological use. The ratio of rostrum length to total length in the common sawshark Pristiophorus cirratus was found to be similar to the largetooth sawfish Pristis pristis but not the knifetooth sawfish Anoxypristis cuspidata. Analysis of the stomach contents of P. cirratus indicates that the diet consists of demersal fishes and crustaceans, with shrimp from the family Pandalidae being the most important dietary component. No prey item showed evidence of wounds inflicted by the rostral teeth. In light of the similarities in microwear patterns, rostral tooth chemistry and diet with sawfishes, it is hypothesised that sawsharks use their rostrum in a similar manner for predation (sensing and capturing prey) and possibly for self-defence.