• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.216-222
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• 2013

The seasonal distribution and abundance of larval fishes in the central and southern surface waters of the East Sea were investigated seasonally during 2011 and 2012. During the study period, the larvae of 39 species belonging to 26 families were collected. The most abundant species were Engraulisjaponicus, which accounted for 97.5% of the total number of individuals collected. Scomber japonicus, Clupea pallasii, Chromis notatus, Cottidae sp., and Coryphaena hippurus accounted for 1.7% of the total. The number of species, number of individuals, and species diversity indices fluctuated with the season. The peak number of species and individuals occurred in September and May, respectively. The larvae of the main species displayed a distinct spatial distribution and seasonal occurrence patterns. E. japonicus and C. notatus widely distributed throughout the study area. During summer and autumn, S. japonicus and C. hippurus were abundant in southern and offshore regions. C. pallasii occurred only in the southern region during winter. The seasonal occurrence and patterns of distribution of the larvae of main species seems were correlated with surface water temperature.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.233-239
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• 2010

Seasonal occurrence and suitable time of control of Tetranychus kanzawai along with the control efficacy of the alternative use of natural predator and miticide was investigated in Rubus coreanus (Miquel). T. kanzawai appeared in late May with its peak between June and July, and decreased after August in R. coreanus. In Iksan, T. kanzawai estimates show peaks 2~4 times per year during the investigation periods from 2006 to 2008 in R. coreanus fields. Suitable time of control of T. kanzawai was in early to mid May. And control effects of T. kanzawai was improved with an alternated control plot, treating miticides in early-occurrence of T. kanzawai and then releasing the natural predator (Phytoseiulus persimilis Anthias-Henriot). Also, the yields of R. coreanus was highest in the alternated control plot of 638kg/10a compared to non-treatment of 559kg/10a.

• Journal of the Korean earth science society
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• v.27 no.6
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• pp.653-658
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• 2006

The seasonal predictability of typhoon activity over the western North Pacific is investigated using an atmospheric general circulation model GCPS. A ten-member ensemble with different initial conditions is integrated for five months using observed sea surface temperature data for each year from 1979 to 2003. It is shown that the monthly variation of occurrence frequency of simulated tropical storms and the distribution of tropical storm genesis location are similar to those of observed tropical storms, but the model is unable to reliably predict the interannual variation of the occurrence frequency of tropical storms. This is largely because the observed relationship between tropical storm occurrence frequency and ENSO is different from the simulated one. Unlike the observation, in which the tropical storm occurrence frequency has no relation to ENSO, the model has a tendency to generate more (less) tropical storms than normal during El Nino (La Nina). On the other hand, the interannual variation of the mean longitude of tropical storms that shows a close connection with ENSO in both observations and simulations is simulated similar to the observation.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.103-109
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• 2004

Seasonal occurrence of Japanese gall-forming thrips, Ponticulothrips diospyrosi Haga et Okajima, and its damage pattern on leaves and fruits were studied at sweet persimmon orchards in Gimhae (orchard A, B) and Changwon, Gyeongnam. Korea in 2002 and 2003. Monitoring adults by yellow sticky traps and inspecting each developmental stage in damaged rolled-leaves revealed that the overwintered adults moved to sweet persimmon orchard from late April to late May, and oviposited inside the rolled leaves. Adults developed from the eggs showed peak occurrence of the first generation adults in early to mid June. Inspection of rolled leaves indicated that the peak occurrences of eggs, nymphs, and pupae of the first generation took place in early to mid May, late May to early June, and early June, respectively. Each developmental stage showed the second small peaks in the late season. Results suggest that most thrips live a single generation per year, but a small portion may develop to the second generation in persimmon orchards. The percent of damaged leaves was highest in Changwon orchard at 9.7％ in early June. Percentage of damaged fruits increased from 0.84％ in early June to 30.2％ in early September in Gimhae B orchard. It was found that the closer the persimmon trees were to the edge of the orchard, the worse damaged the leaves were. Appropriate timing for incorporation of control measures were discussed in relation to the seasonal occurrence of adults.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.9-15
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• 2008

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of $0{\sim}48cm$ from the soil surface and highly distributed in the range of $18{\sim}36cm$. The 74.1 % of wintering chamber were distributed within $18{\sim}36cm$ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

• Journal of Environmental Health Sciences
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• v.19 no.4
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• pp.14-24
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• 1993

The present study was accomplished from October, 1992 to June, 1993 in order to examine the seasonal community structure of aquatic insects and the biological estimation of water quality by the aquatic insects of the Jungneung and Gokneung streams in the Mt. Bukhan. The obtained results are as follows: 1. The total taxa of aquatic insects appeared as 77 species, 45 genera, 28 families in 7 orders. 2. Seasonal occurrence species numbers showed the highest in the autumn of the Jungneung stream (19 species) and in the spring of the Gokneung stream (41 species). Seasonal occurrence individual numbers showed the highest in the summer of the Jungneung and Gokneung streams (5,901, 3,180 individuals) and the lowest in the autumn of Jungneung stream (612 individuals) and in the winter of the Gokneung stream (1,764 individuals). 3. Annual dominance indices showed 0.52 (stJ1)~1.00 (st.J3) range in the Jungneung stream, and 0.47 (st. G1)~0.76 (G2) range in the Gokneung stream. 4. Seasonal species diversity indices showed 0.00 (st J3, whole seasons)~3.12 (st.J1, Spring) range in the Jungneung stream and 0.69 (st. G2, summer) ~3.10 (st. G4, spring) in the Gokneung stream. 5. Biological saprobic system based on species diversity indices of aquatic insects appeared as oligosaprobic area: site J3, $\alpha$-mesosaprobic area: site J2, G2, G3 and $\beta$-mesosaprobic area: site J1, G1, G4.

• Korean journal of applied entomology
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• v.41 no.3
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• pp.177-181
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• 2002

This study investigated seasonal occurrence of Frankliniella occidentalis and its damage on chrysanthemum from 1999 to 2000. F. occidentalis adults were attracted to yellow sticky traps from early April to harvesting time in the field. The highest densities were observed from late April to mid-June in spring culture and from mid-August (just after transplanting) to early September in autumn culture respectively. Seasonal fluctuation in a PVC green house was similar to that in the field. Number of insects per flower were higher in the green house than that in the field. Leaf damages due to the insects were observed from mid-May and increased as chrysanthemum grows (R$^2$ = 0.9200-0.9887$\^$**/, p> 0.01).

• Journal of Aquaculture
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• v.17 no.1
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• pp.51-57
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• 2004

Species composition and seasonal change were examined monthly with shrimp assemblage caught in the coastal waters of Solido, Korea. Samplings were conducted in Solido using a beam trawl from June 2000 to May 2001. In the study period, a total of 16 species of shrimp belonging to six families were collected. Species was dominated by Palaemon gravieri, Crangon hakodatei, Trachysalambria curvirostris and Metapenaeus joyneri. Higher abundance of shrimp occurred in September and November, and lower abundance in June. Species diversity was reached its maximum (0.82) in November and its minimum (0.06) in January. Shrimp species in the study area can be grouped into three groups on the basis of their occurrence patterns: resident, seasonal and temporary species.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.176-179
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• 1990

Seasonal occurrence in each stages of rice water weevil, Lissorhoptrus oryzophilus Kuschel, was studied in paddy field transplanted on May 25, Siehung, 1989. The peak of overwintered adults was late May an that of newly emerged adults was early August. Oviposition occurred in late May and late June and its peak was observed on early June. Larvae were observed from early June to early August and pupation occurred from early July to late August. The first adults of newly emerged rice water weevil was observed on early July and its emergence peak was early August.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.257-269
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• 2017

The occurrence variations of decapods by season and depth off Oryuk Islets, Busan were investigated at seven stations in April and October 2009, July 2010 and January 2011. Decapods were collected by SCUBA diving at 5 m and 10 m depths. 46 species belonging to 18 families in 3 orders were identified. Pilumnus minutus, Pugettia intermedia, Pachycheles stevensii, and Paguristes japonicus were dominant species, comprising 73.0% of total decapods. P. minutus and P. intermedia were abundant in all seasons (except summer) while P. stevensii and P. japonicus were abundant in fall and summer. Dominant species were divided into three groups (resident species, seasonal species and temporary species) on the basis of their occurrence patterns. P. minutus and P. intermedia were resident species while P. stevensii, P. japonicus were temporary species. The species number, density and biomass of decapods were fluctuated by seasons. They were highest in fall and lowest in winter. This study implied that the variations of species number and density of decapods were significantly related with seasonal change of water temperature.