• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.884-889
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• 2002

This paper was carried out from 15 June to 24 December in 2000 in Lake İznik of Turkey, to determine catch per unit effort (CPUE) and size composition of crayfish, Astacus leptodactylus Eschscholtz 1823, captured by fyke-nets of local fishermen. The average CPUE of all size groups was found as 1.65 crayfish/fyke-net/night for fishing season in 2000, but 26.4% of which was below the legal minimum size (crayfish<90 mm). The average CPUE of legal-sized (crayfish$\geq$90 mm) crayfish was 1.10 crayfish/fykenet/night. The annual catch of crayfish was estimated as 2990 tonnes. The length and weight compositions of crayfish captured in the fyke-nets have varied between 60 and 130 mm, and 6 and 71 g, respectively. The mean length and weight were found as 95.5 mm and 28.8 g for all size groups and 100.1 mm and 33.0 g for legal-sized individuals.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.242-249
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• 2023

The aquarium pet trade is a source of potentially invasive crayfish species, which can be subsequently intentionally or unintentionally introduced into new environments. There were 34 species of freshwater crayfish imported into Korea for ornamental purposes. Starting with 1 species in 2008, it shows a trend of continuous increase every year with the maximum of 25 species in 2020. The number of freshwater crayfish imported into Korea for ornamental purposes was 1,172,159, with an annual average of 78,144 being imported. The population also recorded a record high in 2017 with a 38% increase in population imports compared to the previous year. Among the 34 pet crayfish imported into Korea, four species classified as high-risk and managed in the US and Europe were American crayfish (Procambarus clarkii), Cherax quadricarinatus, Cherax cainii, and Cherax destructor. In addition to American crayfish (P. clarkii), 3 types of high-risk invasive crayfish are designated as legally managed species by conducting an ecological risk assessment, raising awareness among importers, retailers and consumers through awareness-raising education on freshwater crayfish, and measures for route management such as species identification and improvement of labeling methods are needed.

• Journal of fish pathology
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• v.19 no.2
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• pp.141-153
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• 2006

Genomic DNA samples isolated from two geographical crayfish (Cambaroides similis) populations in the inland of the Korean Peninsula, at Jeonju (Jeonju crayfish; JJC) and Jeongup (Jeongup crayfish; JUe), were PCR-amplified repeatedly. The six arbitrarily selected primers OPC-03, OPC-06, OPC-09, URP-02, URP07 and URP-09 generated the common, specific, and polymorphic fragments. The sizes of DNA fragments also varied widely, from 100 bp - 2,600 bp. Here, 521 fragments were identified in the JJC population, and 354 in the JUC population: 6 primers generated 60 specific fragments (60/521 fragment, 11.5%) in the JJC population, and 90 (90/354 fragments, 25.4%) in the JUC population. These primers produced 42 polymorphic fragments (8.1%) in the DC population, and 18 (5.1%) in the mc population. Especially these results demonstrate that the primers detected numerous specific fragments. Especially, the decamer primer OPC-06 generated inter-population-common DNA fragments, approximately 400 and 800 bp, respectively, in both the JJC and JUC populations. The universal primer URP-02 also generated inter-population-identical DNA fragments, approximately 350 bp and 600 bp, between the two geographical crayfish populations. Based on the average bandsharing values of all samples, the bandsharing value of individuals within the JJC population was much higher than in the JUC population. The bandsharing value between individuals no. 10 and no. 15 was 0.683, which was the highest between the two geographical populations. The dendrogram obtained by the six primers indicates two genetic clusters: cluster I (CRAYFISH 01 - CRAYFISH II), and cluster 2 (CRAYFISH 12 - CRAYFISH 22). The genetic distance between the two geographical populations ranged from 0.053 to 0.605. Ultimately, the longest genetic distance displaying significant molecular differences was found to exist between individuals in the two crayfish populations, between individuals CRAYFISH no. 02 of Jeonju and CRAYFTSH no. 15 of Jeongup (genetic distance = 0.605).

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.347-350
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• 2017

An epidemiological study was performed to know the recent infection status of Paragonimus westermani metacercariae (PwMc) in freshwater crayfish, Cambaroides similis, from 2 streams in Jeollanam-do, Republic of Korea. Crayfish were collected from creeks in Bogil-do (Island), Wando-gun, and in a creek near Daeheung Temple in Haenam-gun. The infection rate of crayfish with PwMc in Bogil-do was 89.8%, and the metacercarial burden was 37 PwMc per the infected crayfish. Crayfish in a creek near Daeheung Temple were larger and twice heavier than those in Bogil-do. Of them, 96.5% were infected with PwMc. An average of 140 metacercariae was found in the infected crayfish, almost quadruple to those of Bogil-do. There was a strong correlation between the number of PwMc and body weight of the crayfish. These results suggest that P. westermani metacercariae are still prevalent in crayfish of the 2 regions in Jeollanam-do, Korea.

• Parasites, Hosts and Diseases
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• v.47 no.4
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• pp.425-426
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• 2009

The present study investigated the infection status of Paragonimus westermani metacercariae in freshwater crabs (n = 363) and crayfish (n = 31) from October 2007 to October 2008 using the crush method. All of the freshwater crabs, Eriocheir japonicus, were negative for P. westermani metacercariae while 10 (32.3%) of the 31 examined crayfish were positive. The 10 positive crayfish were caught in Haenam, Jeollanam-do, and there were 8-59 (mean 28.4) metacrcariae per infected crayfish. These results suggest that P. westermani metacerariae are still transmitted by crayfish enzootically in southern Korea, and that freshwater crabs may transmit metacercariae only on rare occasions.

• Parasites, Hosts and Diseases
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• v.37 no.1
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• pp.55-57
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• 1999

During the period from October 1996 to November 1998, the infection status of Paragonimus westermani metacercariae in freshwater crayfish (Cambaroides similis) collected from Bogildo (islet), Wando-gun, Chollanam-do, which is known for an endemic area of P. westermani in Korea, were examined. The average infection rate of Paragonimus metacercariae in crayfish was 88.6%, and mean number of metacercariae per infected crayfish was 30.2. This metacercarial density was the highest in the group of weight in 7.1-9.0 g. These results suggest that the natural life cycle of P. westermani is still well-preserved in Bogildo.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.340-347
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• 2019

The red swamp crayfish (Procambarus clarkia) originated from the North America distribute widely as invasive species throughout the world including Europe, Asia, Africa, North America and South America. The red swamp crayfish is also an invasive species in South Korea. We aimed to characterize the occurrence and distribution pattern of the red swamp crayfish, and evaluate the potential distribution of this species in South Korea. In South Korea, the red swamp crayfish was firstly reported in Seoul in 1996, and recently its occurrence is frequently reported at streams or reservoirs at different regions, showing the expansion of its distribution area. The red swamp crayfish has high potential to occur in the nationwide scale in South Korea because of their biological adaptation, effects of climate change, changes of their habitat condition, and various types of human activities. Finally, our results revealed the necessary to conduct an extensive field survey, to keep up a monitoring program for the occurrence of alien species, and to implement a strategy to prevent the dispersal of alien species in the natural ecosystems.

• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.194-200
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• 1986

A study on the population density of crayfish intermediate hosts and infestation status of crayfish with encysted larvae of Paragonimus westermani in Ulchin county, Kyungpook Province, Korea was conducted from May to October in 1986. The population density of the crayfish ranged from 1 to 13, with an average of 4 per man-hour. Among the six habitats, Ducheon had a somewhat higher density than that of the others. Of eight hundred and seventeen crayfish examined, 127 or 15.5 per cent harboured the metacercarial larvae of Paragonimus westermani. The majority of the larvae were found in three parts of the body: most frequently in the cephalothorax, next in the gills, and then in the liver. The average number of metacercarial larvae per infected crayfish ranged from 1.0 to 1.9, with an average of 1.7. Summarizing the results, this study indicates that the population density of crayfish intermediate host and infestation rates for the crayfish with encysted larvae of Paragonimus westermani in Ulchin county of Kyungpook Province is relatively high.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.291-299
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• 1995

Lateral giant (LG)-mediated escape response of crayfish is sensitized by natural traumatic events. Such sensitization has previously been shown to be associated with increased transmission between primary afferents and sensory interneurons at the cholinergic synapse of LG escape reflex circuit. In the present study, it was firstly investigated as to whether transmission is also altered at other synapses of the LG-escape reflex circuit by traumatic shock-induced sensitization. Evidence that traumatic shock also directly affects the excitability of lateral giants is now provided by the finding that traumatic shock produces a significant reduction of the time needed for LG to recruit its contralateral homologue, which is defined as commissural delay. Octopamine, a naturally occurring neuromodulator in the crayfish nerve cord, has also been shown to enhance transmission at the cholinergic synapse between primary afferents and sensory interneurons, and has been conjectured to mediate sensitization. Like traumatic shock, $octopamine\;(10^{-5}-5{\times}10^{-4}\;M)$ also enhanced the efficacy of commissural transmission between lateral giants, as indicated by a significant reduction of commissural delay. This effect was blocked by an octopamine antagonist phentolamine, suggesting a specific action of octopamine on the octopamine receptor present on LGs. These observations suggest that both traumatic shocks and octopamine may cause a rather broad alteration in the excitability of the crayfish nervous system that contributes to the sensitization of the LG escape response.

• Animal cells and systems
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• v.7 no.3
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• pp.191-196
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• 2003

Taxonomic confusion has been presented within freshwater crayfishes of the genus Cambaroides since Starobogatov published morphological definition and revision of the group in 1995. He suggested that Cambaroides should be revised: the C. dauricus, contained three species C. dauricus, C. wladiwostokiensis, and C. koshewnikowi; the C. schrenckii with two. species C. schrenckii and C. sachalinensis. Also Straovogatov did not take into account the previous data. of crayfish distributions. In order to. clear up the confusion, the taxonomy of crayfish sampled from Mongolia, Russia, China, and North Korea was reassessed. Starovogatov's key could not lead to the correct identification. Also, detailed observations of apical robe of the male first pleopod did not support the taxonomy on the genus Cambaroides proposed by Starobogatov in 1995. However, some local variations of morphology exist in rostrum, pleuron, and telson of Asian crayfish. Future studies should be concentrated on whether there are geographical clines of morphology or if taxonomic subdivision is necessary.