Latin American & Caribbean Aquaculture 2023

April 18 - 21, 2023

Panama City, Panama


Jorge Sonnenholzner      

Universidad Técnica de Manabí, Bahía de Caráquez, Sucre, Manabí, Ecuador.      

Echinoderm aquaculture in Latin America is incipient yet, but it represents a new frontier for the highly nutritious marine food production, with native species of high commercial value offering a vast potential when is compared to their weakened artisanal benthic fisheries by over fisheries. Arbacia stellata (Blainville, 1823) is a fast-growing pan-regional sea urchin that can inhabit environments with high salinity fluctuations within estuaries. It presents attractive biological characteristics, and attributes for aquaculture diversification and potential for extraction of macroenergetic biomolecules usable for the nutraceutical industry in Ecuador. Here is reported advances of studies on salinity tolerance on hatchery, diets for larval rearing and produce gonads in adults, and quantification of the pigment EchA in the celomic fluid. Aquaculture of this species would diversify our aquaculture and reducing the pressure on the depleted sea cucumber fisheries in the region.

The critical salinity in the initial stages of life was evaluated (percentage of fertilization, embryonic development and survival) in four salinities: 5, 10, 20 and 32 (control). Control showed 100% fertilization and survival, whose embryonic development was in 20 hours until the prism larva stage. However, salinities below 10 are critical for embryonic development and delayed the gastrula phase by more than 24 h without the formation of prism larvae.

A 25-days feeding trial was performed to evaluate the effect of three diets on the development (from pluteus to competence stage), growth and survival of the larval rearing (1 larvae ml-1), as follows, Diet 1 - RHO: Rhodomonas sp, Diet 2 - CHAE: Chaetoceros gracilis and Diet 3 - T-ISO: T-Isochrysis lutea, and control (starved condition). Five larvae were analyzed per replicate (n = 3) at intervals of 4-5 days. Five variables were measured (postoral arm, midline body, stomach, rudiment length, and pigment concentration). Diet 2 showed the best performance for growth and development, respectively (595.8±2.3 μm in PO length, 216.9±2.0 μm in rudiment) in 14-d after fertilization. Most pigments were in diets 1 (90%) and 2 (63%). Our results suggest that C. gracilis with Rhodomonas sp for obtaining best results in larviculture of A. stellata.

A 98-day feeding trial was performed (n= 88; 29.3±0.2 mm and 14.5±0.3 g mean initial test diameter and weight, respectively) to evaluate the efficacy of three isoproteic low-cost dry formulated diets were prepared for promoting their growth (in test diameter and weight), gonadal yield and survival. Diet 1 (shrimp, Penaeus vannamei), Diet 2 (Sacha Inchi, Plukenetia volubilis) and Diet 3 (mixed). Sea urchins were fed every 48 hours under ad libitum condition. Diets 2 and 3 showed a significantly better performance for growth in test diameter (31.6±0.2 mm and 31.2±0.4 mm), weight (19.1±0.5 g and 19.1±0.5 g), feed conversion ratio and gonadal index. This study indicates that plant-based diets and the combination of various protein sources in the diets produced remarkable biological responses to A. stellata growth.

The content of the red pigment equinochrome naphthoquinone A (EchA) in the coelomic fluid of A. stellata was evaluated from small individuals (16.3±0.3 mm TD; 2.8±0.3 g) and large individuals (45.7±0.4 mm TD; 56.4±1.1 g). The absorbance values (expressed in optical density) were reported in two wavelengths: 387 and 487 nm. There was interaction between large individuals who recorded the highest absorbance peaks for EchA at both wavelengths (387 nm: 0.10±0.01 and 487 nm: 0.05±0.01; P <0.05). The results of this study are consistent with the findings in other echinoids, where the highest production of EchA in coelomic fluid occurs in larger individuals detected at an absorbance of 387 nm.