Effects of dietary carbohydrate on weight gain and gonad production in small sea urchins,Lytechinus variegatus

In this work, the chronic toxicity of a mixture of light-stick chemicals and water was tested. The light-stick is used in fishery activities to catch swordfish. The tubes were collected on the beaches of the Costa dos Coqueiros - BA, Brazil, in the period from 14th to 31st July 2007. The method used was a short chronic toxicity test where embryos of the sea urchins Echinometra lucunter and Lytechinus variegatus were exposed to a stock solution consisting of the supernatant formed from a mixture of sea water and the orange-colored light-stick chemical. After a preliminary test, concentrations defined were 0.002, 0.003, 0.01, 0.02, 0.1, 1.0% of stock solution. The final test ran for 36 hours for E. Lucunter and 24 hours for L. variegatus with 4 replicates for each concentration. The value of EC50 - 36h was 0.062% with confidence limits ranging from 0.042 to 0.079% and the EC50 - 24h was 0.011% with confidence limits ranging from 0.009 to 0.014%, i.e., the chemical mix present in the light-stick is potentially toxic. So, as these flags are commonly used for fishing there is potential danger in their disposal in the open ocean.

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Effect of Feed Protein and Carbohydrate Levels on Feed Intake, Growth, and Gonad Production of the Sea Urchin, Lytechinus variegatus

Journal of the World Aquaculture Society ◽

10.1111/j.1749-7345.2012.00562.x ◽

2012 ◽

Vol 43 (2) ◽

pp. 145-158 ◽

Cited By ~ 32

Author(s):

Hugh S. Hammer ◽

Mickie L. Powell ◽

Warren T. Jones ◽

Victoria K. Gibbs ◽

Addison L. Lawrence ◽

...

Keyword(s):

Sea Urchin ◽

Feed Intake ◽

Lytechinus Variegatus ◽

Carbohydrate Levels ◽

Feed Protein ◽

Gonad Production

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UV radiation influences covering behaviour in the urchin Lytechinus variegatus

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315407055865 ◽

2007 ◽

Vol 87 (5) ◽

pp. 1257-1261 ◽

Cited By ~ 16

Author(s):

Jessica E. Sigg ◽

Karena M. Lloyd-Knight ◽

Jean Geary Boal

Keyword(s):

Uv Radiation ◽

Functional Significance ◽

Sea Urchins ◽

Uv Exposure ◽

Lytechinus Variegatus ◽

Energetic Costs ◽

Trade Off ◽

Familiar Objects

Many species of sea urchins cover their bodies with a variety of materials. One hypothesis for this behaviour is that the urchins are reducing their exposure to UV radiation. The effect of UV radiation on the covering behaviour of twelve sea urchins, Lytechinus variegatus, was recorded and the shells used as covering materials were quantified. During UV exposure, urchins used significantly greater numbers, areas and masses of shells than did urchins during non-UV exposure. Results suggest that not only were L. variegatus covering in response to UV exposure, but they were also making distinct choices regarding preferred covering items. Unlike in previous studies, the urchins did not simply choose familiar objects or even the lightest objects; rather, when exposed to UV radiation they selected intermediate-sized objects, perhaps demonstrating a trade-off between the energetic costs of carrying objects and the physiological costs of exposure to UV radiation. While there appear to be many reasons for why urchins cover, these results indicate that urchin covering is non-random and has important functional significance.

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Glycolytic and hexosemonophosphate enzyme activities in the lantern muscles of the sea urchins, Arbacia lixula (Linn.), Echinometra lucunter (Linn.) and Lytechinus variegatus (Lamarck)

Comparative Biochemistry and Physiology Part B Comparative Biochemistry ◽

10.1016/0305-0491(80)90416-2 ◽

1980 ◽

Vol 67 (4) ◽

pp. 569-573 ◽

Cited By ~ 2

Author(s):

Marilene S.C. Bianconcini ◽

Luis O. Medeiros ◽

Lucília F. Medeiros ◽

Erasmo G. Mendes ◽

Domingos Valente

Keyword(s):

Enzyme Activities ◽

Sea Urchins ◽

Lytechinus Variegatus ◽

Arbacia Lixula

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Chemical defense of Hymeniacidon heliophila (Porifera: halichondrida) against tropical predators

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592010000400006 ◽

2010 ◽

Vol 58 (4) ◽

pp. 315-321 ◽

Cited By ~ 8

Author(s):

Suzi Meneses Ribeiro ◽

Éverson Miguel Bianco ◽

Ricardo Rogers ◽

Valéria Laneuville Teixeira ◽

Renato Crespo Pereira

Keyword(s):

Secondary Metabolites ◽

Fish Consumption ◽

Sea Urchins ◽

Chemical Compounds ◽

Chemical Defenses ◽

Hermit Crabs ◽

Lytechinus Variegatus ◽

Benthic Organisms ◽

Different Types ◽

Ecological Roles

Various benthic organisms have chemical defenses which reduce their predators' consumption. Although their efficiency may be noticed in many organisms, many of their effects are not well- known yet. Multiple ecological roles of secondary metabolites are shown in some sponges, which may represent an adaptative advantage considering the high amount of energy used to produce these chemical compounds. The goal of this work was to investigate the defensive property of the extracts from the sponge Hymeniacidon heliophila against the tropical predators: hermit crabs (Calcinus tibicens), sea urchins (Lytechinus variegatus) and generalist fishes. Extracts obtained with n-hexane, ethyl acetate and acetone/methanol were used in assays and all of them were effective in reducing the consumption by C. tibicens; n-hexane extract reduced the consumption by L. variegatus; and medium polarity extracts reduced fish consumption. Either the variation in action or the multiple ecological roles of the extracts indicates that different types of compounds can be associated to the defensive system produced by H. heliophila.

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