• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.91-97
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• 2005

A taxonomic review of the genus Leiognathus was made based on specimens collected from the coast of Korea from 1997 to 2004. The genus Leiognathus in Korea includes 6 species: Leiognathus elongatus, L. fasciatus, L. lineolatus, L. nuchalis, L. rivulatus, and L. bindus. Leiognathus bindus is reported for the first time in Korea. It is characterized by having bright orange spots between the 2nd and 5th spines of the dorsal fin. Detailed morphological measurements and counts and a key to species of Leiognathus from Korea are provided.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.221-227
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• 1997

Feeding habits of Leiognathus nuchalis collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. Leiognathus nuchalis was a carnivore which mainly consumed copepods and crab larvae. Its diets included small quantities of polychaetes, amphipods, mysids, caridean shrimps. It showed ontogenetic changes in feeding habits. In an initial feeding stage, copepods were major food organisms. However, crab larvae and polychaetes were heavily selected with increasing fish size. Although copepods and crab larvae were major prey organisms for all seasons, the relative proportion of these two food items changed with season.

• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.192-202
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• 2000

Reproductive biology of the slimy, Leiognathus nuchalis was investigated by means of histological methods. Sex ratio was 1.81 : 1 in female to male. Developmental pattern of oocytes was group-synchronous. Testicular structure was restricted spermatogonial testis-type of tubular testis. The size of first group maturity is 7.5 cm in total length. Gonadosomatic index(GSI) of female was the highest in July(12.83) and the lowest in September(1.08). GSI of male was the highest in June(19.0) and the lowest in October(0.24). Hepatosomatic index(HSI) of female showed to be positively correlated with GSI. Thoracic spot index(TSI) showed to be the minimum value from May to July when the maturation and ripe season of gonad. Reproductive cycle of female could be classified into the growing(March~May), maturation(May~June), ripe and spent(June~August), recovery(August~November), and resting stage(November~March). Reproductive cycle of male could be classified into the multiplicative and growing(January~April), maturation(April~May), ripe and spent(June~August), recovery(August~October), and resting stage(October~December).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.666-671
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• 2001

To investigate the food organisms and feeding selectivity of slimy (Leiognathus nuchalis) during the postlarval stage, the gut contents of the fish, captured in Kwangrang Bay in 1995, were observed. The food organisms in the gut were composed of copepod egg and nauplius, Tintinnopsis spp. and Codonellopsis sp. The indices of relative importance (IRI) indicated that Tintinnopsis spp. was the most dominant food item ($80.6\%$), and copepod nauplius was the next ($18.5\%$). Tintinnopsis spp. was the most favorite food item: it occupied $73.8\%$ of gut contents, though it did $39.2\%$ of microzooplankton in the surrounded water. The composition of copepod nauplius was higher in the larvae shorter than 2.0 mm NL. As slimy larvae grew, the size of food organisms in the gut was not changed, and their number increased, and the selectivity for food items increased.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1997.06a
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• pp.143-144
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• 1997

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.33-38
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• 2015

The diet composition of Leiognathus nuchalis were studied using 350 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. L. nuchalis was carnivorous feeder that consumed mainly copepods, crab larvae, and shrimp larvae. Its diet also included small quantities of polychaetes, amphipods, euphausiids, bivalve larvae, and gastropod larvae. The size of L. nuchalis ranged from 3.0 to 9.8 cm in body length (BL). L. nuchalis underwent an ontogenetic dietary shift. 3~5 cm size individuals fed mainly on copepods. 5~7 cm size individuals fed mainly crab larvae and shrimp larvae. 8~10 cm size individuals fed mainly polychaetes. The size increases, the weight of food organisms are constantly increased.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.235-243
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• 1997

The seasonal changes in species composition of fishes in Kwangyang Bay were determined using bimonthly samples with a bottom trawl at five stations from February to December 1990. A total of 32 families 54 species, 9,497 individuals, and 65,838.2g of fishes were collected. Leiognathus nuchalis occupied 64.9% of the total number of individuals. L. nuchalis and Konosirus punctatus occupied 28.8% and 22.3% of the total biomass, respectively. The number of species, the number of individuals and the biomass were lowest in February. More than 20 species occurred during the period when the water temperature was higher than $12^{\circ}C$. The number of individuals was the highest in October. The biomass was the highest in April. The community structure of fish in Kwangyang Bay showed the seasonal variation according to Leiognathus nuchalis and Konosirus punctatus.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.132-141
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• 2007

A total of 27 fish species were collected by a gill net in Masan Bay. The dominant fish species were Konosirus punctatus, Mugil cephalus, Engraulis japonicus, Psenopsis anomala, Lateolabrax japonicus, Leiognathus nuchalis, Chelon affinis, Trachurus japonicus, and these accounted for 87.6% of the total numbers. The numerically dominant fish species made up 95.4% of biomass. These were primarily juvenile species or early larger species. Temporal variation in both species composition and abundance was large: the peak number of fishes occurred in March 2005 and July 2005, whilst biomass of fishes was the highest in September 2005 and November 2005. Fish numbers as well as biomass was lowest in November 2005. Temporal changes in the abundance of fishes corresponded with temperature. A gill net can be used as an alternative fishing gear to collect pelagic fishes commercially, although a gill net has a strong selectivity for the target fish species or for size.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.84-90
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• 2020

We investigated carbon and nitrogen isotope ratios (δ¹³C and δ¹⁵N) of the slipmouth Leiognathus nuchalis to reveal the effects of body size, feeding strategy and spatial distribution on the food resource utilization during the migration in the Seomjin estuary and Gwangyang Bay. The δ¹³C values of L. nuchalis caught in the Seomjin estuary where the salinity is lower than 30 psu were much lower than those in the deep-bay area of Gwangyang Bay. Such a spatial heterogeneity in δ¹³C values of the L. nuchalis clearly indicates active feeding within the estuarine habitat. In contrast, the δ¹⁵N values of L. nuchalis showed a consistency among sites, indicating that this species occupies identical trophic level across the whole area. The slipmouth distributed throughout the bay area, reflecting its euryhaline characteristics. However, the distribution pattern appeared to be separated according to body size into smaller individuals in the low-saline estuary and larger ones in the deep bay. Overall results support the plastic feeding strategy of the slipmouth from zooplanktonic (estuarine habitat) to epibenthic (deep-bay habitat) feeder during the migration between estuarine to deep-bay habitats.

• Korean Journal of Ichthyology
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• v.6 no.1
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• pp.60-70
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• 1994

To study the composition and distribution of the ichthyoplankton in Kwangyang Bay, they were sampled at eight stations from February to December 1990, Abundance was the highest in June, and the number of taxa was the highest in August. Engraulis japonicus, Leiognathus nuchalis, Konosirus punctatus and Argyrosomus argentatus were dominant among 6 taxa of pelagic eggs. Engraulis japonicus, Gobiidae, Korwsirus punctatus, Argyrosomus argentatus and Leiognathus nuchalis were dominant among 21 taxa of fish larvae. The number of taxa was smaller than the previous study. Abundance during winter was low due to the reduction of abundance of winter spawning species. Ammodytes personatus and Enendrias fangi.