• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.705-713
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• 2022

The feeding habits of Hexagrammos otakii were studied by analyzing the stomach contents of 508 specimens collected from July 2009 to December 2010 off the Yeosu coast of Korea. The total length of the H. otakii specimens ranged from 10.7 to 41.5 cm. H. otakii was found to be a bottom-feeding carnivore that mainly consumed brachyura, amphipoda, but also sonsumed cephalopoda, pisces, anomura, polychaeta, and gastropoda. It was shown through relative importance analysis that the benthic share was 58.1% for brachyura, 24.5% for amphipoda, 7.5% for caridea, and 7.3% for pisces. Brachyura was the main prey item for H. otakii, occupying 35% of the stomach contents. The proportion of brachyura and amphipoda decreased with the growth of H. otakii, and their decrease paralleled the increased consumption of pisces. The shift in feeding habits to larger prey organisms with increasing fish size seems to be one of survival strategies to maximize net energy gain.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.333-339
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• 2023

The aim of this study was to collect information regarding the sex ratio, size at sexual maturity, and the primary spawning period of Hexagrammos otakii. The sex ratio (female : male) was observed to be 1 : 1.2 (n =739 : 906, with females comprising 81.6% of the population). The gonadosomatic index (GSI) exhibited its highest values in November for females and October for males, coinciding with the primary spawning period from November to January. The total length required for 50% sexual maturity was determined through a logistic regression model and found to be 23.1 cm for females.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.234-234
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• 1995

• Korean Journal of Ichthyology
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• v.29 no.2
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• pp.117-123
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• 2017

Stomach contents of Hexagrammos otakii collected from mid-western coast of Korea were analysed to determine dietary composition, and ontogenetic and temporal dietary variations. Fish total length (TL) ranged between 5.6 and 32.4 cm. H. otakii primarily consumed amphipods, carid shrimps and teleosts, but also ate various benthic crustaceans and other invertebrates with small amounts. Carid shrimps and teleosts dominated the diet of both immature and mature fishes. Amphipods and polychaetes were secondary, and the former more frequently consumed by smaller specimens, while the latter was more abundant in the diets of larger fishes. DISTLM (distance-based linear modelling) showed diet composition of H. otakii varying significantly with TL, season and water temperature, but did not with maturity.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.235-235
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• 1995

• Animal Systematics, Evolution and Diversity
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• v.9 no.1
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• pp.61-67
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• 1993

Lepeophtheirus tuberculatus, n. sp., is described from the greenlings Hexagrammos otakii and H. agrammus from the Sea of Japan off Mangreung, Korea. This species has been confused with L. scuttger Shiino, 1952 and L. sheni Boxshall and Bellwood, 1981. However, the new species apparently differs from the latter two species.

• Journal of fish pathology
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• v.14 no.1
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• pp.54-58
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• 2001

The seasonal trends of plasma protein and glucose concentrations in marbled soles(Limanda yokohamae) and greenlings(Hexagrammos otakii), and the influence of transport stressor on those levels were investigated. Total plasma protein levels of marbled soles and greenlings in late spring and summer were significantly higher than those in winter(January). Plasma glucose levels were consistently increased according to elevation of water temperature both in marbled soles and greenlings. Transport stressor gave rise to decrease of plasma protein levels and increase of blood glucose levels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.221-232
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• 2015

Broadband echoes measured in live chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, and fat greenling Hexagrammos otakii with different morphologies and internal characteristics were analyzed in time and frequency domains to understand the species-specific echo feature characteristics for classifying fish species. The mean echo image for each time-frequency representation dataset obtained as a function of orientation angle was extracted to mitigate the effect of fish orientation on acoustic scattering. The joint time-frequency content of the broadband echo signals was obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The SPWVDs were analyzed for each echo signature of the three fish species. The results show that the time-frequency analysis provided species-specific echo structure patterns and metrics of the broadband acoustic signals to facilitate fish species classification.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.2
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• pp.84-94
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• 2007

The comparative feeding ecology of greenling Hexagrammos otakii and Schlegel's black rockfish Sebastes schlereli populations was investigated in the Jangbong tidal flat near Incheon, Korea. Monthly samples were taken using a modified otter trawl from November 1999 to January 2001. The stomach contents of 124 greenling and 115 Schlegel's black rockfish were analyzed. The diet of H. otakii was dominated by the amphipods Gammaropsis iaponicus, Caprella scaura, Isaeopsis sp. and Monocorophium acherusicum, the shrimps Latreutes mucronatus and Alpheus japonicus, the mysid Neomysis orientalis and the bivalve Mytilus edulis. In contrast, S. schlegeli mainly fed on the mysids N. orientalis, N japonica, and N. awatschensis, the shrimps Exopalaemon carinicauda, A. japonicus and L. mucronatus, and the fish Pholis fangi and unidentified gobiids. A comparison of the frequency and abundance of food items showed that crustaceans (e.g. amphipods, mysids and shrimps) were important foods for both species. Their main dietary components, however differed which is probably due to differences in the spatial distribution of the two species and their prey items. In conclusion, greenling and Schlegel's black rockfish, despite being sympatric on a tidal flat have distinct food habits and low dietary overlap (Schooner's index: 0.1). These results indicate, to some extent, resource partitioning for the maximum utilization of available foods in the tidal flat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.3
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• pp.287-295
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• 2013

The growth, respiration, ingestion, and ecological efficiencies of Hexagrammos otakii larvae and juveniles reared on different diets and temperatures were estimated. A factorial experiment using two diets [non-enriched hatched Artemia nauplii (NEA) and enriched Artemia nauplii (EA)] crossed with two temperatures [natural seawater temperature (NT, $5.1-8.5^{\circ}C$) and heated seawater (HT, $13{\pm}0.5^{\circ}C$)] was conducted to investigate growth and energy budgets of Hexagrammos otakii larvae and juveniles. The energy used by larvae and juveniles for 6 weeks was calculated using data on ingestion, growth, respiration, excretion, and egestion. In the NT trials, the energy used for growth by larvae and juveniles was 0.121 and 0.129 Kcal in the NEA and EA treatments, respectively. Assimilation efficiency at NT were 78.0% and 80.2% in the NEA and EA trials, respectively. Gross growth efficiency ($K_1$) were 60.5% and 62.3% and net growth efficiency ($K_2$) was 77.56% and 77.71% in the NEA and EA trials, respectively. In the HT trials, the energy used for growth by juveniles was 0.189 and 0.212 Kcal in the NEA and EA trials, respectively. Assimilation efficiency at HT was 86.4% and 95.1% in the NEA and EA trials, respectively. Values of $K_1$ and $K_2$ at HT were 69.5% and 80.43%, respectively, in the NEA trials, and 73.9% and 77.66%, respectively, in the EA trials. These results suggest that enriched Artemia nauplii and higher temperatures ($13{\pm}0.5^{\circ}C$) are effective for rearing larvae and juveniles of H. otakii.