Search

A population of sea urchins, Paracentrotus lividus, from the central west coast of Portugal was studied to characterise their reproductive biology and possible relationships with environmental factors. An annual gametogenic cycle was found, with a broad spawning season, from May to November, according to a relatively synchronous gamete maturation process. Depending on the environmental factors (temperature, photoperiod), two separate periods could be distinguished, with more individuals maturing and spawning at the same time. When this happened, the first event evolved when temperature rose to a critical point, and the second occurred afterwards, when temperature decreased significantly. Notwithstanding, it was found that individuals matured later than previously described for other populations (e.g., north of Portugal), mostly in late spring, with a higher gonadosomatic index in May. A new classification scale was proposed for identifying the stages of P. lividus gametogenic cycle, based on new findings. It contributed to its simplification and easier comprehension. This study provides useful information for a differentiated sustainable management of P. lividus, according to local conditions. Establishing a closed harvesting season might be considered, based on the differences observed between Portuguese populations and other European ones. [ABSTRACT FROM AUTHOR]

Paracentrotus lividus (Lamarck 1816) has high‐value reddish‐orange gonads that are regarded as a delicacy. In this study, three jellified diets have been tested for 90 days to assess the effect of different diets on P. lividus somatic and gonadal growth, gonad color, and reproductive state. All diets contained agar as a gelling agent and consisted of: maize and spinach (A); maize, spinach, and macroalga Laminaria digitata (B); and maize, spinach, and pumpkin Cucurbita maxima (C). Diet B was the most successful in promoting somatic growth with regard to test diameter (1.2 mm month−1) and total wet weight (79.9 mg ind−1 day−1). The individuals from Diet A presented a higher final gonadosomatic index (9.07 ± 2.39%) where all sea urchins initially presented with an index of 3.33 ± 0.02%. Diets A and C led to a marked advance (p <.05) in the gametogenic cycle (66.7% and 46.7% of the individuals with mature gametes, respectively), while Diet B resulted in less‐developed gonadal stages, which are more appropriate for commercial purposes in terms of sensorial characteristics appreciated by the consumers. The gonad color analyses confirmed a redder roe in females and also the suitability of C. maxima as a potential gonad color enhancer for P. lividus. [ABSTRACT FROM AUTHOR]

In this study, the effects of three diets were investigated to enhance Paracentrotus lividus production for commercial purposes. P. lividus were fed ad libitum for 80 days with: diet A—fresh Codium tomentosum Stackhouse, 1797; diet B—formulated using a jellified mix of macroalgae and vegetables, including C. tomentosum (20%), Coralina sp. Linnaeus, 1758 (17%), cabbage Brassica oleracea var. capitata Linnaeus, 1753 (30%), carrot Daucus carota Linnaeus, 1753 (30%) and agar (3%) as a gelling agent. Diet C consisted of maize Zea mays Linnaeus, 1753 (56%) and New Zealand spinach Tetragonia tetragonoides (Pallas, 1781) Kuntze, 1891 (44%). Their effects on the gonadal and somatic growths, gonadosomatic index (GI) and gametogenesis were evaluated, as well as on the total lipid content and fatty acid composition of sea urchin's gonads. Diet A provided high values of eicosapentaenoic acid (EPA). Gonads of sea urchins fed with diet A were found mostly in growth and maturation stages of gametogenesis and showed the lowest lipid content. Sea urchins fed with diet B presented their gonads in the reabsorption stage and had the highest values of omega‐3 polyunsaturated fatty acids (PUFAs). Sea urchins fed with diet C were in the early stages of gametogenesis and had the highest values of lipid content, plus omega‐6 PUFAs. Once as an ingredient in a balanced mix with vegetables, C. tomentosum can be a key factor to the development of new promising high‐quality and low‐cost feed for P. lividus roe enhancement. [ABSTRACT FROM AUTHOR]

The market value of sea urchin roe (female and male gonads) depends on several quality criteria, such as size, color, texture, and flavor. Sea urchins given dry pellet feed often produce large gonads, but the preferred bright orange color has been difficult to achieve without the inclusion of supplementary dietary carotenoids. Gonad color depends on carotenoid concentrations (CC), and is influenced by several factors, including diet and sea urchin sex. This study aimed to evaluate the impact of sea urchin sex, gonad size, and maturation level on gonad color and CC. Small Paracentrotus lividus urchins (18 mm test diameter) were fed every 48 h with three diets of similar proximate composition (protein: 31–33% dry matter DM, fat: 9–10% DM; carbohydrates: 45–46% DM). The diets were formulated with fishmeal, algae, and plant-based ingredients and supplemented with β-carotene (100 mg Kg−1). The nutritional trial was conducted in three recirculatory aquatic systems equipped with 40 L glass tanks guaranteeing triplicates by diet with an initial biomass of 5 g L−1. The gonadosomatic index (GSI), gonad maturity and color of 15 urchins per replica were analyzed at mid-trial (103 days, T1) and at the end of the trial (173 days, T2), and compare with initial condition (baseline). At each sampling event, the color of female (F) and male (M) gonads was analyzed using qualitative (four-level visual scale) and quantitative methods (Commission Internationale de l' Eclairage CIE L *, a * and b * color parameters). Additionally, CC was determined by spectrophotometry in pooled samples freeze-dried gonads per replica and sex and compared with baseline. At T1, 59 females and 71 males were analyzed, and results showed that females presented larger (GSI = 7.50) gonads with higher CC (117.5 μg g−1 DM) than males (GSI = 5.16 and CC = 76 μg g−1). Female gonads also presented a more intense color (a * = 8.8, b* = 17.13) than males (a* = 5.1, b* = 12.49). At T2, 61 females and 62 males were analyzed and, except for a high percentage of female gonads classified as color grade I (57%), the differences on gonad color and CC between sexes identified in T1 became non-significant. In general, the gonad color tended to become lighter (L *, baseline: 34.8 and T2: 47.2) and yellower (b *, baseline: 12.5 and T2: 17.50), and CC decreased (baseline: 201.8 μg g−1 DM and T2: 31.6 μg g−1 DM) with increasing gonad weight (baseline: 0.16 g and T2: 0.77 g) and GSI (baseline: 3.0% and T2: 9.9%). In conclusion, this study shows that the carotenoid concentration and color attributes of sea urchin gonads are influenced by sea urchin sex and gonad size. The different diets and the carotene supplementation had little or no effect on the gonad CC and color attributes, indicating that the sources and concentrations of carotenoids in the diets were not sufficient to allow the accumulation of pigments in the gonads needed to enhance the color of P. lividus urchins. • The bright yellow and orange color is an important characteristic of high-value roe (gonads). • Sea urchins were fed 3 diets using algae, fishmeal, and plants ingredients and supplemented with β-carotene. • Gonad carotenoids concentration and color were evaluated over time in relation to sex, size, and maturity. • Carotenoids concentration was negatively correlated with gonad size. • Color was influenced by sex with females showing higher percentage of bright orange roe. [ABSTRACT FROM AUTHOR]

The common sea urchin Paracentrotus lividus (Lamarck, 1816) is the most consumed echinoid in Europe. It is considered a seafood delicacy, given its high-valued gonads. In sea urchins, temperature probably represents the most important abiotic factor affecting several physiological processes and it is essential to better establish optimal reference conditions for aquaculture. In this study, four rearing temperatures (18 °C, 20 °C, 22 °C and 24 °C) were tested in wild-caught adult P. lividus , from the west coast of Portugal. The animals were fed an agar-based artificial diet, over a period of 90 days. The effect of temperature was tested in terms of test diameter and total wet weight, feed intake, gonadosomatic index (GI) and reproductive development. Thus, linear growth rate (mm month−1), daily growth rate (% day−1), total wet weight gain (mg ind.−1 day−1) and total feed intake (g day−1 ind.−1) of sea urchins were calculated at the end of the trial. Although feed intake was relatively similar between groups, the results showed a consistent response for biometric parameters regarding the different temperatures regimes. The rearing temperature of 22 °C promoted the highest test diameter (.53 mm month−1) and total wet weight (47 mg ind.−1 day−1) growth. Sea urchins from the same group (22 °C) presented the highest final GI of 9.3%, a 163.5% increase in comparison to the initial value, after the fasting period (3.5%). This temperature also promoted the highest gonad maturation levels, both in males and females. Although increasing temperatures (until 22 °C) generally produced favourable rearing results, the 24 °C regime led to lower somatic and gonadal growth, plus slower gonad maturation results. Overall, P. lividus fed with a formulated diet and reared at 20–22 °C, showed considerable somatic and gonadal growth, as well as a significant sexual maturation, which will allow to obtain developed gonads and gametes all year round. On the other hand, 18 °C promoted a slower progression in the gametogenic cycle, which may contribute to produce gonads with better organoleptic properties for human consumption. • Paracentrotus lividus was reared at four different temperatures (18, 20, 22, 24 °C). • Test diameter and total wet weight growth rates were highest at 22 °C. • Gonadal growth and maturation were highest at 22 °C, both in males and females. • Maturation was less pronounced at 18 °C, being more appropriate for human consumption. [ABSTRACT FROM AUTHOR]