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Abstract.— Juveniles of four species of tropical sea cucumbers of moderate to high commercial value were studied to determine their potential for being propagated asexually by evaluating their survival and regeneration times after being forced to undergo transverse fission. The four species were Holothuria fuscogilva.H. nobilis, Actinopyga mauritiana, and Stichopus variegatus. Rubber bands placed midbody on the sea cucumbers provided an effective yet simple technique to induce fission. Posterior parts of animals had similar or higher survivorship and shorter regeneration times relative to the anterior parts. Combining this information with that collected earlier on adults indicated that smaller animals (both anterior and posterior parts) had higher survivorship (up to 100%) and shorter regeneration times (as fast as 41 d) relative to adult animals of the same species. Using percent weight retained after processing into beche‐de‐mer, a rough measure of body wall thickness, and size of the animal relative to the adult weight, a multiple regression equation was calculated to predict percent survival and regeneration times for both anterior and posterior parts. The equation illustrated that small, thin‐walled species would have the highest survivorship and shortest regeneration times. As the percent weight retained increased, as would be the case with more thick‐walled species, and as the animal approached the adult weight, survivorship declined and the regeneration time increased.

The U.S. Environmental Protection Agency (EPA) has developed a “Seven‐Day Fathead Minnow Larval Survival and Growth Test” for measuring the toxicity of effluents. This study evaluated the ease and performance and the intra‐ and interlaboratory variability of this 7‐d test using two reference toxicants (sodium pentachlorophenate and potassium dichromate), two refinery effluents, and one low‐volume internal waste stream from an electric power plant. Ten different laboratories representing academia, private industry, contractors, the state EPA, and the U.S. EPA participated in this study. The reference toxicants were tested twice during two separate test periods, and each effluent and waste stream was tested once. Using EPA's criteria for a successful test, 90% of the 140 planned tests were completed as valid tests. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted concurrently (spatial variability), expressed as the coefficient of variation (C.V.), ranged between 5.9 and 15.6% and between 9.1 and 26.1%, respectively. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted at two different times (temporal variability), expressed as C.V., ranged between 14.5 and 25.3% and between 17.6 and 22.7%, respectively. The interlaboratory variability of the survival (LC50) and growth (IC50) results, expressed as C.V., ranged between 24.1 and 43.7% and between 22.4 and 88.0%, respectively. Overall, the variability of the 7‐d fathead minnow test was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.

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Six species of tropical sea cucumbers (Echinodermata) of high to moderate commercial value were evaluated as to their potential for being propagated asexually by induction of transverse fission. The species considered were Thelenota ananas, Holothuria fuscogilva, Actinopyga mauritiana, A. miliaris, Stichopus chloronotus, and S. variegatus. Rubber bands placed midbody on the sea cncumbers provided an effective yet simple technique to induce transverse fission. Although fission could be induced in all six species, only T. ananas and S. chloronotus had the ability to regenerate both anterior and posterior parts into whole animals. Other species showed no or low potential for regeneration (H. fuscogilva, A. mauritiana) or regeneration of only the posterior part into whole animals (S. variegatus, A. miliaris). Both T. ananas and S. chloronotus had survivorship of nearly 80% or greater. S. chloronotus regenerated anterior and posterior parts into whole animals within 3 mo. In contrast, T. ananas regenerated the posterior part into a whole animal within 5 mo while the anterior part was regenerated within 7 mo. Consequently, weight recovery began earlier with S. chloronotus relative to T. ananas.