• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.524-533
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• 2019

Sea urchins are hugely destructive of marine forest ecosystems. This study aimed to determine the behavioral response of purple sea Urchins Heliocodaris crassispina to food and an electrical stimulus and to investigate the attraction radius of these stimuli, with an eye to the development of technology for controlling sea urchin numbers. Ten purple sea urchins, housed in circular acrylic tank, were tested against various attractant stimuli. In addition, an experiment was conducted with 200 purple sea urchins in a large water tank to observe movement patterns and the attractiveness of various stimuli. In the smaller experiment, eight out of 10 sea urchins were attracted to food, and these attractive effects were maintained in all except one of the affected urchins. However, the attractant effects of the electrical stimulus were maintained in only three sea urchins. The results of the larger experiment indicated that differences in the attractant power of food and an electrical stimulus were 54%-78%, and approximately 5-15% of sea urchins were attracted by the electrical stimulus.

• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.201-204
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• 2015

A sea urchin was collected from 140 m deep at Gapado which is nearby Moseulpo in Jejudo Island, Korea on 30 June 2010. This specimen was classified as Echinolampas koreana H.L. Clark 1925, belonging to family Echinolampadidae of order Echinolampadoida based on its morphological characteristics. This order and lower categories are newly recorded from Korea. Distinct morphological characters of this species are as follows: test is relatively high. Abactical system has four large genital pores. Periproct is slightly sunken and situated below equator line. Peristome is very small and rather deeply sunken. Tridentate and ophiocephalous pedicellariae are present. Color in alcohol is light purple. These morphological characters are re-described with illustrations.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.83-88
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• 2014

A new shell divider was manufactured according to the principle of the lever in order to improve working efficiency in collecting the gonad of Sea Urchin, Anthocidaris crassispina, around the coast of jeju. It was composed of three parts of a pair of handles for grasping power, a fulcrum and a pair of knives for action with 21cm in length and 13cm in width. The operating efficiency of the shell divider was tested out in three place of Jeju coast. Statistical significances of differences of working time between test groups were calculated according to the t-test with the level of significance. In dividing the shell of sea urchin, the average of about 3 seconds of working time by the shell divider was less than that by a knife. At the result of t-test, the statistical significance in the working time existed between the divider group and the knife group. On the other hand, the working time among the divider operators showed no significant differences. It is concluded that the shell divider is more efficient than a knife in traditional operating.

• ALGAE
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• v.29 no.3
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• pp.203-215
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• 2014

As global warming continues over the coming century, marine organisms will experience a warmer, more acidic ocean. Although these stressors may behave antagonistically or synergistically and will impact organisms both directly (i.e., physiologically) and indirectly (i.e., through altered species interactions), few studies have examined the complexities of these effects in combination. To address these uncertainties, we examined the independent and combined effects of elevated temperature and $pCO_2$ on the physiology of the adult sporophyte stage of giant kelp, Macrocystis pyrifera, and the grazing of the purple sea urchin Strongylocentrotus purpuratus. While elevating $pCO_2$ alone had no effect on M. pyrifera growth or photosynthetic carbon uptake, elevating temperature alone resulted in a significant reduction in both. However, when M. pyrifera was grown under elevated temperature and $pCO_2$ together, growth and photosynthetic carbon uptake significantly increased relative to ambient conditions, suggesting an interaction of these factors on photosynthetic physiology. S. purpuratus held under future conditions generally exhibited reduced growth, and smaller gonads than urchins held under present-day conditions. However, urchins fed kelp grown under future conditions showed higher growth rates, partially ameliorating this effect. Feeding rates were variable over the course of the experiment, with only the first feeding rate experiment showing significantly lower rates for urchins held under future conditions. Together, these data suggest that M. pyrifera may benefit physiologically from a warmer, more acidic (i.e., higher $pCO_2$) ocean while S. purpuratus will likely be impacted negatively. Given that kelp-urchin interactions can be important to kelp forest structure, changes to either of these populations may have serious consequences for many coastal environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.302-308
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• 1998

The growth of the purple sea urchin, Anthocidaris crassispina, has been investigated using reproduction plates as a chararter of the age determination. The samples were collected on the coast of Daepo, in the southern part of Cheju Island from August, 1995 to July, 1996. Monthly growth of test diameter mainly occurred from December to March. The obvious growth, however, were not observed between April and June which seemed to be the resting period. This resting period well corresponded to the time of annual ring formation which was estimated from the analysis of the marginal growth rate. The growth curve fitted well with Bertalanffy equation: $$L_t=46.65 (1-e^{-0.283(t+9.210)}),\;W_t=44.90 (1-e^{-0.283(t+9.210)})^3$$