• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.4
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• pp.191-199
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• 1989

Research on the acoustic properties of fish has been carried out by a number of scientific workers from the earliest days of applying acoustic techniques to fish biomass estimates. This paper describes measurements of the target strength of Cyprinus Carpio, which measurements made at 50KHz in the experimental water tank. The results obtained are as follows: 1. The target strength(dB) of the fish has a directivity pattern quite similar to that of a transducer. The maximum value of target strength(dB) is obtained when the fish is insonified to its head-tail axis either from the dorsal or from the ventral side. 2. Empirical relationship between target strength(dB) and body length(cm) of the fish can be estimated as TS=20 Log L-65.4 where TS is the target strength of the fish and L is the body length of the fish. 3. The relationship between target strength(dB) and body weight(g) of the fish can be estimated as TS=6.7 Log W-53.7 where W is body weight of the fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.3_4
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• pp.103-104
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• 1971

A cod, Gadus macrocephalus TILESIUS was studied on the length-weight relationship. The fish were sampled from those caught by set nets for cod in the Yellow Sea during the period from April 1964 to May 1964. The data for this study were taken from 247 fish. The relationship between the body length (X) in mm and body weight(Y) in g is indicated as follow : 160mm to 339mm : $Y=0.000001225X^{3.42706}$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.117-119
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• 1970

A goby Synechogobius hasta (TEMMINCK et SCHLEGEL) was studied on the length-weight relation-ship, and the fish were sampled from the closed tributary and the lower part of the Naktong River, near Pusan, during the period from November of 1967 to December of 1968. The data for this study were taken from 1,050 fish. The relationships between the body length (X) and body weight (Y) are indicated as follows: 7.5cm to 32.5cm: $Y=0.09863X^{2.17926}$ 7.5cm to 19.5cm: $Y=0.04995X^{2.472l6}$ 28.5Cm to 32.5Cm: $Y=0.0004127X^{3.67265}$ The normal relative growth was not found in fish between 20.5cm and 27.5cm in body length, because of the maturity of gonads and spawning.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.251-255
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• 1976

Three hundred and sixty two specimens of Plecoglossus altivelis were randomly sampled from Chunji Stream in Seogwipo, Cheju-Do, during the period from 25 Aug., 1973 to 14 Feb., 1974 to investigate the relationship between total length and dody weight as well as the condition factor during the spawning period. Results obtained are summarized as follows : The relationships between total length and body weight are calculated as below, respectively : $W=0.008639\;L^{3.1806}$ : Prior to spawning period $W=0.01830\;L^{2.7689}$ : During spawning period The above equations differ each other significantly. Nevertheless, the significant difference is not found between sexes. The mean body length decreased during the spawning season. The fact seems to be caused by the death of large fish after spawning. The condition factor was $13.45\%_{\circ}$ on the average in August. The value decreased continuously from September, giving the minimum mean value of $10.25\%_{\circ}$ on Nobember 29. But the value increased again, showing $11.18\%_{\circ}$ in next February. Majority of the fish survived until next year was small ranging from 11 to 12cm in total length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.154-160
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• 1970

The present paper deals with the growth of yellow croaker by scale age reading. This study is based on material from 596 specimens caught by the Danish seine in the Yellow Sea during the period from June 1967 to April 1968. Ring marks of the scale were formed from April to July, corresponding to the spawning season of the fish reported by Bae (1960). Growth rate of each radius of the ring was approximately 0.73. The relationship between the total length and radius of scales, and the relationship between the body weight and total length are represented by the following equations respectively: L=61.350R+50.184 $$W=4.298L^{3.227}\times10^{-3}$$ Maximum total length calculated by the diagram of Walford's growth transformation, $$L_{n+1}=0.6866L_n+10.8730$$, was 346.9mm. Growth curve of the fish can be expressed by the following von Bertalanffy's equation : $$L_t=346.9(1-e^{-0.376(t+0.609)})$$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.171-178
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• 1981

The growth of Sebastes alutus was studied by scale reading to check the change of growth rate at the early stage of life. Lee's phenomenon was recognized on the scale measurements except thc first ring radius. No evidence was found to support the change of growth rate at early stage. Von Bert-alanffy's growth equation was estimated with the back-calculated fork lengths, $1_t=357.8(1-e^{-0.6124(t+1.8566)}),\;and\;W_{\infty}=784.4g$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.110-116
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• 1970

The fresh_water shrimp, Palaemon modestua is one of the most important types of bait f[r fishing and can be found abundantly in the Nak-Dong River. The larval development of Palaemon modestua in the laboratory was reported by Liu (1949), Kown and Uno (1968), but they didn't give any ecological features in the natural environments. Shrimps were collected from the Nak-Dong River near Pusan, once a month from July to December 1953 and from February to June 1969 respectively. The following is a summary of the results: 1. They breed from April to September, mainly in July. 2. A generation of this type of shrimps appears to be approximately one year and after breeding they die off up untill the end of October. 3. The sex ratio (female=100) is $44.2\~95.5$ (mean 78.5) and goes down during spawning seasons. 4. The minimum size of the ovigerous female is approximately 0.5 gram in body weight, 29mm in body length and 7mm in carapace length. 5. Most shrimps of $31\~41mm$ In body length lay eggs. 6. The relationship between the boby length (X) and the number of eggs (Y) is: $$Y=0.0000203937X^{3.5668}$$ 7. The relationship between the body length (X) and the body weight (Y) is: $$Y=0.099801X^{2.85407}$$ in female. $$Y=0.004198X^{3.40614}$$ in Male. 8. The relationship between the carapace length (X) and the body weight (Y) is: $$Y=5.56008X^{2.25503}$$ in female. $$Y=5.09541X^{2.28875}$$ in male. 9. The relationship between the carapace length (X) and the body length (Y) is: Y= 5.07540+3.36057X in female. Y=4.90514+3.47791X in male.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.7-16
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• 1971

This paper deals with the numbers of vertebrae, gill rakers and relative growth of the Pacific saury, Cololabis saira along the eastern coast of Korea in May, July and December 1970. About 90 percent of the total fish population possessed 64-66 vertebrae with the mean of 64.80 and the mode of 65. The number of gill rakers varied from 33 to 44 in December with the mean of 37.08. With regard to the number of vertebrae and gill rakers of the medium (26.0-28.0 cm in fork length) and large (30.0-31.0 cm in fork length) sized groups, there are similarities between the northbound modium sized group and the southbound large sized one, and also between the southbound medium and southbound large sized groups. Although no correlation was found between the numbers of vertebrae and gill rakers, in December the number of vertebrae of the large sized group exceeded that of the medium sized group, and on the other hand the number of gill rakers of the large sized group was fewer than that of the meduim sized one. There was a tendency of decreasing in ratio of the head length to the fork length as the latter increased, The relationships between the fork length and the head length varied depending on the northbound and southbound migration of the fish. The same tendency was also seen in the relationship between the fork length and the body weight. The body weight increased from July to December (from medium to largo sized group) showed more than twice than that from December to the following July (from medium to large sized group). The coefficient of fatness remained constant in December, but a distinct variation was found between the medium and large sized groups in July, corresponding to the spawning sea-son of the fish. Relatively higher coefficient was found in December as compared to that found in July.

• Korean Journal of Ichthyology
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• v.8 no.2
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• pp.16-22
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• 1996

Age and growth of Epinephelus akaara were determined using samples collected from the south western sea of Korea. Thin - sectioned otoliths showed relatively well defined annuli when examined under dark - field microscope. Because the fish do not feed at the temperature under $10^{\circ}C$, the annuli in otoliths are considered to be formed during the period between December and April. Considering that the peak spawning season is July, the first annulus must have been formed in 0.5 year after birth. The oldest fish examined was 9 years old, and the largest one was 47cm. The body length(L, cm) was linearly related to the otolith radius (R, ${\mu}m$) : L= - 2.84+7.01 R. Back-calculated lengths for each age using the relationship between body and otolith size were well adjusted to the Von Bertalanffy growth curve : $L_t$=55.5[1-exp{-0.162(t+0.128)}]. Using relationship between length and weight ($W_t$=0.00608$L^{3.21}$), growth in weight was expressed by Wt=2409(1-exp{-0.162(t+0.128)}]$^{3.21}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.93-102
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• 1970

1. On the basis of the samples collected on the eastern coast of Koje-Do from May to September, 1969, studies have been made on the growth and the relationships between the carapace length and the body length, and between the carapace length and the body weight of Penaeus japonicus Bate. 2. The mean carapace length of P. japonicus was 51mm in May, 57mm in June, 47mm in July and 50mm in September respectively. 3. As a result of the present studies two populations of P. japonicus exist in waters around Koje-Do, namely the spring and fall spawning populations. 4. The relationship between the carapace length ($\iota$) and the body length(L) and between the carapace length and the body weight (W) are indicated by the following equations: May $$L=2.6544{\iota}+3.1258$$ $$W=1.892{\iota}^{1.9844}$$ June $$L=2.8659{\iota}+2.1796$$ $$W=1.082{\iota}^{2.4323}$$ July $$L=2.5840{\iota}+3.3090$$ $$W=1.290{\iota}^{2.3094}$$ September $$L=2.4234{\iota}+4.5775$$ $$W=1.599{\iota}^{2.1857}$$ 5. With regard to the relationships between the carapace length and the body length and between the carapace length and the body weight there is no significant difference between the populations spawning in June and September. 6. The relationships between the carapace length ($\iota$) and the body length (L) and between the carapace length and the body weight (W) for the samples cultured at three different localities are indicated by the following equations: Koje-do $$L=3.7738{\iota}+0.0805\;(r=0.934)$$ $$W=0.4690{\iota}^{3.0713}$$ Oma-do $$L=2.993{\iota}+1.6455\;(r=0.990)$$ $$W=0.6328{\iota}^{2.6579}$$ Kumdang-do $$L=3.2749{\iota}+0.9055\;(r=0.983)$$ $$W=0.5768{\iota}^{2.8076}$$ 7. During the larval stages the relationship between the body length (L) and the rearing day (D) is indicated by the following equations: Zoeal stages (1-3) L=0.1279D+0.2686 (r=0.979) Mysis (1) - Post larva (6) L=0.1697D+0.5634 (r=0.994) Post-larvs (7) - Post larvs (21) L=0.1344D+1.9501 (r=0.978)