• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.896-902
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• 1997

Feeding habits of Syngnathus schlegeli were studied by using samples collected from the eelgrass bed in Kwangyang Bay, Korea from January 1994 to December 1994. Syngnathus schlegeli was a carnivore which mainly consumed copepods and epiphytal gammarid amphipods. Its diets included small quantities of caprellid amphipods, tanaids and mysids. It showed ontogenetic changes in feeding habits. In its initial feeding stage, copepods were major food organisms. However, gammarid amphipods were heavily selected with the incretment of the fish size. Food availability in the eelgrass bed changed seasonally. Its main food items were changed according to variations of food availability. Copepods were mainly consumed in spring, and gammarid amphipods in summer and fall.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.83-89
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• 2020

This study provides a detailed morphological description of larvae obtained from Urocampus nanus and Syngnathus schlegeli male brood fish over 20 days of culture in the laboratory. In both species, mating takes place when several males each spread their brood pouch like a wing to attract a female's attention. When the female begins to swim upward, the males follow her and receive her eggs in their brood pouches. Newborn larvae of U. nanus and S. schlegeli had already completed formation of dorsal and caudal fin rays, but not of pectoral fin rays. Pectoral fin rays were completely formed 15 days after release in S. schlegeli and 20 days after release in U. nanus. The ratio of caudal fin length to standard length increased until 8 days and decreased thereafter in S. schlegeli, while in U. nanus this ratio declined continuously after hatching. The larvae of the two species were very similar in external morphology, but well distinguished by the number of dorsal fin rays (15-16 in U. nanus vs. 39-43 in S. schlegeli), the presence of a membrane under the tail (absent in U. nanus vs. present in S. schlegeli), and the presence of melanophores in the dorsal fin (present in U. nanus vs. absent in S. schlegeli). Based on this study, U. nanus appears to be evolutionally more similar to pipefish than to seahorse.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.40-48
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• 2022

Seahorses, which have been cultivated since the 2000s, are economically very important. Gas bubble disease (GBD) is a significant concern in the cultivation of seahorses; therefore, this study aimed to determine the cause of GBD-induced death in two species of Syngnathidae (Syngnathus schlegeli and Hippocampus haema). Rod-shaped bacteria were observed histopathologically and identified as Vibrio splendidus by conventional and real-time PCR analyses. The lethality of V. splendidus varies depending on the host's immune status, and the disease can be prevented through water quality management or improvement of the breeding environment. In this study, the GBD lesions (gas bubbles) were observed at 12℃, 8.0 mg/L of dissolved oxygen, 30 ppt of salinity, and pH 7.7. In addition, rod-shaped bacteria, infiltration of inflammatory cells, and extensive serous exudate were confirmed in the lesions where gas bubbles were found. PCR analysis was able to detect V. splendidus, possibly a secondary infection of the immunocompromised syngnathid fish. Understanding the risk of immunity control and the correlation between these lesions and causal agents will be of great help to the aquaculture industry and the ornamental fish market.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.225-233
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• 2011

This is the attempt to study the fish assemblages in eelgrass bed of Jeogu on Geoje Island, Korea. Samples were collected by surf net monthly from August 2009 to July 2010. A total 38 species, 2,335 individuals, and 5,289.8g of fishes were collected. The dominant species were Chaenogobius annularis, Gymnogobius heptacanthus, Rudarius ercodes, Siganus fuscescens, Ditrema temminckii, Takifugu niphobles, Aulichthys japonicus, Pseudoblennius cottoides, Syngnathus schlegeli, Sebastes schlegelii, Pterogobius elapoides, Urocampus nanus, Takifugu pardalis, Hypodytes rubripinnis which accounted for 94.2% of total number of individuals of fish collected. Eelgrass biomass showed a peak in August (DW 121.5g/m$^2$), low values in November (DW 74.9 g/m$^2$) to February (DW 49.3g/m$^2$), and started growing from May (DW 112.8g/m$^2$). Gymnogobius heptacanthus, Sebastes schlegeli, Takifugu niphobles, Syngnathus schlegeli, Urocampus nanus were collected year-round with no clear relationship to the biomass of eelgrass bed.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.119-127
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• 2011

Fish species composition in eelgrass bed of Geoje island, Korea was determined using monthly samples collected by a surf net from August 2009 to July 2010. A total of 31 species, 1,387 individuals and 4,776.5 g of fishes were collected. The dominant species were Rudarius ercodes, Gymnogobius heptacanthus, Ditrema temminckii, Takifugu niphobles, Hypodytes rubripinnis, Chaenogobius annularis, Aulichthys japonicus, Syngnathus schlegeli, Pterogobius elapoides which accounted for 89.3% of total number of individuals of fish collected. Eelgrass biomass showed a peak in August (DW 154 g/$m^2$), low values in November (DW 31 g/$m^2$) to February (DW 41 g/$m^2$), and started growing from May (DW 78 g/$m^2$). The biomass of fish increased by the catch of a large number of Gymnogobius heptacanthus, Chaenogobius annularis, Pterogobius elapoides, Rudarius ercodes and Pseudoblennius percoides in May and September when the eelgrass grew fast. Meanwhile, Syngnathus schlegeli, Urocampus nanus and Aulichthys japonicus were collected year-round with no clear relationship to the biomass of eelgrass bed.

• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.191-200
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• 2012

Fish species composition in eelgrass bed of Punghwa-ri in Tongyeong, Korea was determined using monthly samples collected by a surf net from November 2010 to October 2011. During the study period, a total of 30 species, 5,511 individuals and 6,933.4 g of fishes were collected. The dominant fish species were Pholis nebulosa, Syngnathus schlegeli, Rudarius ercodes, Pseudoblennius cottoides, Sebastes inermis, and Aulichthys japonicus which accounted for 93.4% of total number of individuals collected. Most fishes collected in the eelgrass bed belong mainly to small fish species or juveniles of large fish species. Eelgrass shoot density reached a peak in April 2011, and then decreased to a minimum in January 2011. The seasonal variation of fish assemblage in an eelgrass bed of Punghwa-ri was correlated to the variations in the water temperature, eelgrass density and biomass, and abundances of major prey organisms.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.202-220
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• 1997

A total of 57 species of fish species was collected by a trawl from the eelgrass bed in Kwangyang Bay. The dominant species were Pholis nebulosa, Syngnathus schlegeli, Leiognathus nuchalis, Pseudoblennius cottoides, Sebastes inermis, Favonigobius gymnauchen, which accounted for 69.9% of the total numbers of fish collected. Fish collected in the study area were primarily small fish species or early juveniles of large fish species. Only about 10% of fishes which were collected in the eelgrass bed exceeded 15cm in standard length. Seasonal variations in both species composition and abundance were major characteristics in the study area. The peak abundance occurred in spring, while the number of species was the highest in fall. However, both the number of species and abundance of fishes showed the lowest values in winter. High species diversity indices were observed in fall. Temperature, eelgrass standing crop and abundance of food organisms influenced seasonal changes of the fish community in the study area. More abundant and more diverse fishes were collected during nighttime than daytime.

• Korean Journal of Ichthyology
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• v.6 no.2
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• pp.93-98
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• 1994

The pipefish Syngnathus schelegeli was reared in the laboratory from May to June 1991 and observed the morphology of eggs and larvae squeezed from the parent fish(male). The diameter of inseminated eggs ranged from 0.72 to 1.01 mm (n=50), and yolk in yellow color were found in the eggs. The newly beared larvae were 10.9 mm in average standard length and had 59~60 myomeres. In 6 days after bearing, the post larvae attained 13.8 mm in average standard length and the low jaw was developed. The larvae of 14.1 mm in average standard length (8 days after bearing) had 40~42 fin rays in dorsal fin, 9 in caudal fin and 13~14 in pectoral fin. The juvenile of 14.7 mm in average standard length (10 days after bearing) had the well elongated snout along with the opercular and caudal fin similar to adult stage's.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.8-18
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• 2005

A total of 33 fish species were collected by a small beam trawl from an eelgrass bed in Myoungjuri of Jindong Bay, Korea. The dominant fish species were Hexagrammos otakii, Pholis fangi, Repomucenus valenciennei, Pseudoblennus cottoides, Pholis nebulosa, Rudarius ercodes, Syngnathus schlegeli, and Sebastes schlegeli. These 8 fish species accounted for 79.5% of the total number of individuals collected. The fishes collected in the study area were primarily small fish species or juveniles of large fish species. Seasonal variations in both species composition and abundance were large; higher numbers of fish occurred from April to June 2002, while biomass was the highest in September 2001 and 2002. Seasonal changes in fish abundance corresponded with eelgrass biomass and abundance of food organisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.509-517
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• 1986

Abundances of small fishes that utilized eelgrass meadows of Hansilpo, Chungmu, were analyzed to determine fish species composition and monthly changes of this temperate seagrass fish community during 1983-1986. A total of 4,646 fishes that comprised 35 species in 19 families was collected during the period of investigation. Pholis taczanowskii, Pseudoblennius cottoides, Tridentiger trigonocephalus, and Sryngnathus schlegeli predominated in ichthyofauna that occupied the eelgrass meadows most of the year. These four most abundant fish species accounted for approximately $64\%$ of the number of fish collected. Juveniles of economically valuable fish species such as Sebastes inermis, Platycephalus indicus and Limanda yokohamae were also collected in the study area. Seasonal changes in both species composition and abundances of fish populations were major characteristics in these eelgrass meadows. A peak abundance of total fishes occurred during spring, with a secondary peak during fall. The lowest abundance of total fishes occurred in winter. Each abundant fish species showed its own seasonal abundance pattern, and a peak abundance 1-3 months separated from other species with some overlap of the increased larval recruitment.