• Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.136-140
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• 2004

We examined the ovaries of 312 robust tonguefish (Cynoglossus robustus) collected each month from January to December 2001, off the coast of Yeosu, Korea. The samples were used to investigate robust tonguefish reproductive activity. Monthly changes in the gonadosomatic indexindicated that spawning peaked between June and August. Fish size at first spawning was 15-19 cm total length (TL). Over $50{\%}$ of female fish 25-29 cm TL were sexually mature, and this rose to $100{\%}$ for female fish 35-39 cm TL. The tonguefish spawned four or more times during the spawning season. Most females commenced spawning in their second year. The relationship between total length (cm TL) and fecundity (F) was F=528646Ln(TL)-1E+06.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.111-117
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• 2011

The population dynamics of Pandalus gracilis was investigated in the southeastern coastal area of Korea between May 1998 and April 2000. Of the 4,127 specimens, 57% were identified as females, 39% as males, and 4% as transitional hermaphrodites. The number of females was greater than that of males and transexuals. A significant correlation was observed between the number of transitional hermaphrodites and ambient seawater temperature. Growth parameters were estimated using the modified von Bertalanffy growth function model incorporating seasonal variation in growth using the program ELEFAN. Females grew faster and reached a larger size-at-age than males (K=0.65/y and $L_{\infty}$=17.86 mm carapace length [CL] for females; K=0.51/y and $L_{\infty}$=14.70 mm CL for males). Mean size and age (95% confidence limits) at sex transition, calculated from growth parameters, were 7.07 mm carapace length and 1.05 years, respectively. The reproductive strategies of pandalid shrimps are discussed in terms of the type of sex transition.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.118-122
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• 2011

Polysiphonia senticulosa Harvey (Ceramiales: Rhodophyta) was recorded for the first time in Korea, and its vegetative and tetrasporangial morphologies are described. This species is characterized by the combined features of having a vegetative axial segment with 4 pericentral cells, a main axis without cortication, pseudodichotomous branching, branches with sharply pointed apical cells, flexuous branches hooked backward below, the presence of cicatrigenous branches, axillary endogenous stichidia, and the production of 1-3 tetrasporangia per stichidium. Based on this study, it is distinguished from Polysiphonia morrowii Harvey by its flexuous branches and the number of tetrasporangia produced per stichidium.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.269-273
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• 2014

Coralline algae, the algal whitening phenomenon-causing seaweeds, are characterized by calcareous deposits in the cell wall. The viability of the coralline algae Lithophyllum yessoense and Corallina pilulifera was quantitated using a triphenyltetrazolium chloride assay and eight calcification inhibitors. Among these inhibitors, ferric citrate showed the strongest inhibition of coralline algae viability. The concentrations of ferric citrate conferring 50% inhibition were 1.7 and 3.8 mM for L. yessoense and C. pilulifera, respectively. Thus, at a specific concentration and in a localized area, ferric citrate may be used to prevent the blooming of coralline algae.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.235-244
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• 2002

Three penaeid species, Penaeus monodon, P. semisulcatus and Metapenaeopsis lata are reported from the southeastern coast of Korea. P. monodon and P. semisulcatus have been incorrectly known so far as P. bubulus and P. monodon, respectively, in Korea. M. lata is the first record of this species from Korean waters. Morphological diagnoses are given with coloration and distribution for the three species.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.302-307
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• 2002

The characteristics of trace metals were investigated in the sediments of the Mokpo coastal area, southwestern coast of Korea. Surface sediments were collected in September 3, 2002 after a strong rain event. The sampling sites were categorized into the inner and outer harbour based on salinity distribution and difference of trace metal concentration was evidence between these two zones. The enrichment factor (E' F) of Zn and Cr were high at the mouth of Mokpo Harbour and $E \cdot F$ of Cu was high at the east-south of Dali Island. One hundred percent of Mn and Pb samples and $40\%$ of Zn samples had E' F higher than 1 suggesting that they are accumulated in the entire outer of Mokpo Harbour. Trace metals appeared to be accumulated in the inner harbour by input of sediments in the discharged freshwater from Young-San River during strong rainfall whereas they were influenced by natural sedimentation and human activities in part.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.220-224
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• 2003

In order to determined the appropriate processing season of Pacific oyster (Crassostrea gigas), 30 individuals cultured in Kamak Bay on the southern coast of Korea were taken bimonthly 7 times a year, and seasonal variation of edible portion weight, edible portion yield and coefficient of fatness were investigated. There were close relationships between edible portion weight (X) and total weight (Y) and between coefficient of fatness (X) and edible portion yield (Y), which were expressed in regression lines, i.e. Y=0.2709X-1.9094 (r=0.9254) and Y=44.0596X+ 15.1127 (r=0.8485), respectively. From the results of seasonal variation of edible portion weight, yield and coefficient of fatness, the appropriate processing season of raw Pacific oyster was between winter and spring, that is, between December and following April the next year.

• Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.84-89
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• 2004

Feeding habits of Sillago japonica collected from in an eelgrass (Zostera marina) bed in Jindong Bay, Korea were studied. S. japonica was a carnivore which consumed mainly gammarid amphipods, polychaetes, bivalves, caridean shrimps and crabs. Its diets also included a small amount of fishes, copepods and caprellid amphipods. The diet of S. japonica underwent significant size-related changes; small individuals (<5cm SL) fed mainly on gammarid amphipods and crab larvae, while proportion of polychaetes and bivalves increased with increasing fish size and gammarid amphipods were also important prey for medium size individuals (5.1-9.9cm SL). The large individuals (>10cm SL) ate polychaetes, caridean shrimps and crabs. The dietary breadth of S. japonica were varied with size. The diet of S. japonica also underwent seasonal changes that could be related to differences in prey availability; gammarid amphipods were mainly consumed in spring and polychaetes in summer.

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.196-199
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• 2007

The spermatozoa of Leiocassis nitidus are relatively simple cells composed of a spherical head, a short midpiece, and a tail, as in most Siluriformes. The ultrastructure is characterized by the following features: Acrosome absent, as in most teleosts; around nucleus about $1.8\;{\mu}m$ long, with a deep nuclear fossa containing the proximal and distal centrioles and mitochondria. Two centrioles approximately $180^{\circ}$ from each other; 10 or more mitochondria surrounding the axoneme (with a 9+2 microtubular pattern), arranged in two layers in the postnuclear cytoplasm and separated from the axoneme by the cytoplasmic canal. Two lateral fins on the same plane as the two central microtubules; doublets 3 and 8, which are ultrastructural characteristics of the sperma tail unlike other siluroids laking the lateral fins.

• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.395-399
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• 2015

We observed seasonality and other characteristics of spawning in the greenling Hexagrammos agrammus off the coast of Tongyeong. Eleven spawning grounds were identified between November, 2013 and January, 2014. The fertilized eggs of H. agrammus were assigned to developmental stages I, II, III, and IV. Based on this classification, we showed that the spawning season extended from the end of October to mid-January. H. agrammus used diverse seaweed species attached to shallow bedrock as spawning substrata that provided good camouflage. Two to seven egg masses were fertilized around the holdfasts of individual seaweeds at depths of 1.2-4.0 m. We identified species-specific reproductive traits of H. agrammus during the spawning season, including strong parental care of the fertilized eggs.