No abstract

In Colombia, oil industry is interested in developing offshore hydrocarbon exploration, activity that causes spills of harmful substances in marine areas. It is essential to understand the effects that those substances may cause in native organisms in the inflence zones. This manuscript proposes an assay with an autochthonous organism from the Colombian Caribbean, that may be used as a bioindicator of contamination. The acute toxicity (CE50) of a flid used in offshore exploration was assessed on basis on the fecundity of the sea urchin Lytechinus variegatus, using as a standard toxic pentahydrated cooper sulfate. The protocol for obtaining the gametes and fecundation was previously standardized with the reference toxic which is used to guarantee and validate its results in terms of effective concentration (CE50). The fecundation percentage should be greater than 85% in order to validate the assay in the control treatment, that was carried out by fecundating 2000 oocytes with 50 x 106 sperms. In each replicate 200 oocytes (10%) were counted in order to determine the percentage of fecundation. The obtained CE50 value of pentahydrate copper sulphate was 20.45 ± 1.90 mg.L-1 and 3649 mg.L-1 ± 400 mg.L-1 corresponding to the suspended particulate phase of mud, which was prepared from a mud-water relationship of 1:9 (v/v). The results show a high sensitivity degree of the L. variegatus gametes to the action of the drilling mud of offshore hydrocarbon exploration, which shows the sensitivity of the test organism to these substances and its potential use as bioindicator of pollution.

Seahorses natural populations are declining, due to theri demand in traditional Chinese medicine, its consumption in oriental countries and their attractive as ornamental species; then, all the Hippocampus species of the genus are threatened fishes. Culture under controlled conditions is an option for their conservation and sustainable use; however, it is necessary to fin the appropiate techniques to culture them, especially to raise the fry. In this study the effect of live food on growth an survival of Hippocampus reidi fry was evaluated. During the first 11 days they were fede with Artemia nauplii and rotifers enriched, since the day 11 to 46 only with enriched Artemia metanauplii with four commercial products: Protein Selco Plus® (PSP), marine fish food Azoo 9 in 1® (AZ), Scott Emulsion® (SE) and Isochrysis galbana microalgae (IG). The largest growth in therms of weight and height was observed in seahorses fed with enriched Artemia with PSP (160.13 mg and 4.44 cm respectively), which was significantly higher than the other treatments, which were kept in a range of 81-86-97380 mg in weight and 3.62-3.72 cm in size (F3.12 = 9.63, p = 0.0049 by weight and F3.12 = 5.12, p = 0.0288 in height). There were not significant differences in survival; however the highest percentage was in PSP diet (74.42%) and lower in SE (51.60%) (F3.12 = 1.08, p = 0.4095).

Understanding nutrition and its effect on growth is essential for developing diets in commercially important species. This study aimed to evaluate the larval development of Callinectes sapidus fed with rotifers (Brachionus plicatilis) enriched with Chlorella pyrenoidosa (Ch) as a main protein source and a lipid emulsion (Spr) rich in highly unsaturated fatty acids. The enriched compositions had seven ratios Ch/Spr (w/w): 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, and 40/60. The enriched rotifers with each ratio were called diets. Lipids increased progressively between 100/0 and 40/60 (7.48 to 11.30 g 100 g-1), as well as energy (21.88 to 23.16 kJ g-1), but the protein level did not show a clear trend (63.93 and 67.50 g 100 g-1). The production response of blue crab larvae showed significant differences within diets (P < 0.05). The highest survival (29 to 34%) was obtained in the 50/50 and 40/60 treatments. In the 40/60, 50/50, and 60/40 diets, the larval cycle was shorter (P < 0.05), and the megalopa stage was reached between 49 and 52 days of culture. Metamorphosis to megalopa occurred between the fifth and eighth molts; its corresponding weight varied from 0.72 to 1.33 mg, the length varied from 2,632 to 2,926 µm, and Le Cren´s condition factor varied from 0.83 to 1.16. The most important factor in the production response was the diet lipid content, which was significantly correlated with the survival, weight, length, and condition factor of C. sapidus larvae. Findings of the present study can be applied in future efforts towards mass culture of blue crab larvae in the Caribbean and can also potentially be used to study other crustacean species with similar characteristics.