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- High dietary protein, n − 3/n − 6 ratio and β-carotene enhances Paracentrotus lividus (Lamarck, 1816) larval developmentPublication . Gomes, Ana S.; Lourenço, Sílvia; Santos, Pedro M.; Neves, Marta; Adão, Pedro; Tecelão, Carla; Pombo, AnaThe nutritional characteristics of microalgae affect the growth, survival and fatty acid composition of sea urchin larvae. This study aimed to evaluate the influence of nutritive characteristics of single microalgal diets in Paracentrotus lividus (Lamarck, 1816) larval development, growth, and condition. Larvae of P. lividus were fed with three monospecific microalgal diets, Rhodomonas sp. (Rho), Dunaliella tertiolecta (Duna) and the diatom Chaetoceros calcitrans (Chae), and their development and growth were analysed until competence. Additionally, the fatty acid (FA) profile of larvae was analysed at competence and compared with the FA profile of the correspondent diet. The three groups of larvae attained competence simultaneously with differences in growth performance. The larvae fed with Chae attained the largest stomach and the shortest post-oral arm. The larvae were able to accumulate long-chain polyunsaturated fatty acids (PUFA), such as docosahexaenoic (DHA, C22:6n − 3), eicosapentaenoic (EPA, C20:5n − 3) and arachidonic (ARA, C20:4n − 6) acids, either by assimilation and retention of dietary FA or by the synthesis from α-linolenic acid (ALA, C18:3n − 3) and linoleic acid (LA, C18:2n − 6). Furthermore, the low DHA/EPA ratio and high EPA/ARA and n − 3/n − 6 ratios of Rho and Chae and the high levels of the β-carotene present in Chae improved larval growth and development. In conclusion, the results indicated that of the three microalgal diets tested, C. calcitrans provided important nutritional characteristics, especially in terms of FA composition and carotenoids, improving P. lividus larval growth and condition.
- Morphometric approach to the development of Paracentrotus lividus larvae fed with different microalgae dietsPublication . Lourenço, Sílvia; Gomes, Ana Sofia; Santos, Pedro M.; Raposo, Andreia; Ferreira, Susana; Pombo, Ana
- A morphometric approach to the development of Paracentrotus lividus larvae fed with different microalgae dietsPublication . Lourenço, S.; Gomes, A.S.; Santos, Pedro Castelo Filipe Moreira dos; Raposo, A.; Ferreira, S.M.F.; Pombo, AnaParacentrotus lividus is the most valuable sea urchin species in the European roe markets. Its economic value has been driving an intense exploration of wild populations leading to their over-exploitation in several areas of the Mediterranean and eastern Atlantic coast. The full production of P. lividus in aquaculture can potentially supply the European market for sea urchin roe reducing the impact over the wild populations. However, the low survival rates of sea urchin planktonic stages represent a critical bottleneck for the full cycle production for commercial purposes. Together with the zootechnical challenges, the selection of a suitable microalgal diet is fundamental to overcome this challenge. In the present study, we conducted two larvae rearing experiments testing the effect of five microalgae diets in the larvae development, age at competence and survival. The experimental diets tested were: Rhodomonas baltica (rho); Phaedactylum tricornutum (phae); Chaetoceros calcitrans (chae); a mix diet of rho and phae (1:1); and a mixed diet of rho and chae (1:1). The larvae were reared in closed system in triplicate tanks (50 L) at a density of 4 larvae/mL with seawater temperature ranging between 18.5 and 20°C. The daily feed concentration was adapted to the larval stage of development and standardized to the ratio between microalgae biovolume. Larvae samples were regularly collected to measure larvae body length, body width, post-oral arm length and the rudiment length. Linear models were fitted to the larval measurements and the model residuals were analyzed as an indication of larvae body condition. The larval survival was assessed volumetrically every two days. The results showed that the larvae fed with rho attained age at competence (at 18 days post fecundation, DPF, in experiment I and at 16 DPF at experiment II) earlier than larvae fed with phae, chae or with the mixed diets. On the other hand, the larvae fed with the rho and chae mixed diet presented higher survival rate (32 %). Moreover, the preliminary analysis of the linear model residuals showed that the mixed diet promoted the development of larvae with better condition. These results indicated that the rho diet promoted a reduction of the planktonic phase albeit with costs in terms of larval condition and survival rate.
- Motivation and preferences of Portuguese consumers’ towards sea urchin roePublication . Lourenço, Sílvia; Mendes, Susana; Raposo, Andreia; Santos, Pedro M.; Gomes, Ana S.; Ganhão, Rui; Costa, José L.; Gil, Maria M.; Pombo, AnaSea urchin roe is a gastronomic delicacy appreciated worldwide and Portugal is the third largest consumer nation of seafood. However, sea urchin roe is recognized as a seafood by few members of the national coastal communities. Motivated by an increasing interest of gastronomic and aquaculture sectors in producing this seafood, a survey was conducted among the participants of gastronomic festivals aiming to characterize the motivations and preferences regarding sea urchin roe. The results showed that a high percentage of consumers would be willing to eat sea urchin roe in a restaurant, and approximately half of these were not motivated to buy it in the supermarket. The consumers willing to buy sea urchins in the supermarket, would buy it as the whole urchin or the chilled/frozen roe. In conclusion, sea urchin roe can be characterized as a high valued shellfish to be consumed in restaurants.
- Somatic growth and gonadal development of Paracentrotus lividus (Lamarck, 1816) fed with diets of different ingredient sourcesPublication . Lourenço, Sílvia; Cunha, Beatriz; Raposo, Andreia; Neves, Marta; Santos, Pedro M.; Gomes, Ana S.; Tecelão, Carla; Ferreira, Susana M. F.; Baptista, Teresa; Gonçalves, Sílvia C.; Pombo, AnaSea urchins’ gonads are a delicacy highly appreciated worldwide. In Europe, Paracentrotus lividus is one of the most valuable edible sea urchin species and a desired target for aquaculture. One of the challenges of echinoculture is to increase the sea urchins’ growth rate during the on-growing phase and reducing the production cycle required to obtain sea urchins of commercial size (test diameter ≈ 50 mm). The present study aimed to evaluate the growth and gonad development of P. lividus urchins fed with three dry diets for 15 weeks. The diets were formulated with ingredients of three different sources: an algae-based, a fishmeal-based and a cereals-based diet. The somatic growth was assessed by biometric indicators like the linear and specific growth rates. The gonadal development was assessed by the gonadal somatic index (GSI), gametogenesis level, proximate composition and fatty acids profile. The results obtained showed high growth rates in all the three diets tested (0.44% per day). The sea urchins fed with the cereals diet presented the highest GSI (8.22%) with higher proportion of gonads in growing and premature stages. The proximate composition of the sea urchins’ gonads was significantly affected by diet and sea urchins’ sex, particularly the lipid content. Concomitantly, fatty acids (FA) profile of the gonads was influenced by both diet and sea urchins’ sex with saturated and polyunsaturated FA playing an important role in this differentiation.
- Effects of single and mixed-diatom diets on growth, condition, and survival of larvae of the sea urchin Paracentrotus lividus (Lamarck, 1816)Publication . Gomes, Ana; Lourenço, Sílvia; Santos, Pedro M.; Raposo, Andreia; Mendes, Susana; Gonçalves, Sílvia C.; Ferreira, Susana M. F.; Pombo, AnaThe development of rearing protocols promoting the larval development, pre and postmetamorphosis are key for echinoculture. Mixed diets combining diatom with other microalgae have been used with success and Rhodomonas sp. (Rho)-based diets showed promising results in larval survival. This study was aimed to evaluate the rearing success of Paracentrotus lividus larvae fed with mixed diets combining Rho with two diatoms, Phaedactylum tricornutum (Phae) and Chaetoceros calcitrans (Chae) in two experiments. In experiment I, the effect of the mixed diet of Rho and Phae (Mix I) was compared with monospecific diets of both species, while in experiment II, Rho was combined with Chae (Mix II) and compared with both monospecific diets. In experiment I, larvae fed with Rho I and Mix I diets grew faster than larvae fed with Phae I diet, attained the competence earlier with survival rates of 15-16%. In experiment II, the larvae fed with Rho were larger and the larvae fed with Mix II attained the highest survival rate (32.22%). The analysis of the larval biometric models showed that the larger larvae, with bigger stomachs, and shorter post-oral arm attained the age-at-competence earlier with higher survival rates. In conclusion, the larvae fed with a combination of Rho with the selected diatoms showed identical growth performance and condition to larvae fed with Rho monospecific diet but obtained higher survival rate. These results indicate that mixed-diatoms diets may be more suitable for P. lividus larval rearing.
- Temporal changes in sex-specific color attributes and carotenoid concentration in the gonads (roe) of the purple sea urchin (Paracentrotus lividus) provided dry feeds supplemented with β-carotenePublication . Lourenço, Sílvia; Raposo, Andreia; Cunha, Beatriz; Pinheiro, Joaquina; Santos, Pedro M.; Gomes, Ana; Ferreira, Susana; Gil, Maria Manuel; Costa, José L.; Pombo, AnaThe 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.
- Physical and chemical tagging methods for the sea urchin Paracentrotus lividus (Echinodermata: Echinoidea)Publication . Santos, Pedro M.; Quintella, Bernardo Ruivo; Jacinto, David; Gomes, Ana; Saldanha, Carolina; Lourenço, Sílvia; Lopes, Patrícia Mega; Correia, Maria João; Mateus, David; Cruz, Teresa; Pombo, Ana; Costa, José LinoThe sea urchin Paracentrotus lividus (Lamarck, 1816) (Echinodermata: Echinoidea) is an important economic resource in Europe, but intense harvesting has led to the collapse of several natural populations. Echinoculture, associated with restocking and stock enhancement practices, is an alternative to this problem. In these procedures, reliable individual identification through tagging is a valuable source of information. However, very few studies address the effect of tagging methods on P. lividus and the tagging of marine invertebrates still presents several challenges: decreased growth, high mortality rates and low tag retention rates. Under laboratory conditions, the present study evaluated the effectiveness of three tagging methods (passive integrated transponders [PIT-tags], coded wire tags [CWTs] and calcein) on wild P. lividus for 60 days in terms of total wet weight, total weight gain (mg ind.−1 day−1), survival and tag retention. The final total wet weight was significantly higher in the untagged (control) group than in the PIT-tagged group. Survival rate was 100% for the PIT-tag, calcein and control groups, and 97% for the CWT group. Tag retention differed significantly according to the tagging method: 100% in the calcein group, 76.7% in the PIT-tag group and 38.0% in the CWT group.
- Effect of different microalgae diets on larvaldevelopment of sea urchin Paracentrotus lividus(Lamarck, 1816): impacts in growth, survival andsettlementPublication . Gomes, Ana Sofia Santos; Lourenço, Sílvia Alexandra Pereira; Pombo, Ana Margarida Paulino Violante; Ferreira, Susana Margarida de FreitasO ouriço-do-mar Paracentrotus lividus (Lamarck, 1816) é considerado um recurso alimentar de elevado valor. O aumento da procura por parte dos consumidores e os métodos de captura provocaram uma redução drástica dos stocks naturais ao longo das costas do Mediterrâneo e do Atlântico Nordeste. As práticas de aquacultura podem representar uma resposta, desempenhando um papel muito importante na limitação da captura das populações naturais. A transição entre o ambiente planctónico para o ambiente bentónico representam fases críticas do ciclo. Em cativeiro, a utilização de dietas artificiais para acelerar a maturação das gónadas é fundamental para impulsionar as produções. Neste estudo avaliou-se a eficácia de uma dieta MSD para garantir a maturação das gónadas de P. lividus. O principal objetivo deste trabalho foi otimizar a produção de larvas de P. lividus através da escolha de uma dieta ótima e identificar um fator indutor de metamorfose e assentamento. Os indivíduos adultos foram recolhidos na zona intertidal da costa de Peniche (Portugal) e foram mantidos em RAS e alimentados com a dieta MSD durante 60 dias (C1) e 120 dias (C2). Após este período, os indivíduos mantidos em cativeiro foram submetidos a análises biométricas, histológicas e bioquímicas. O GI foi maior nos indivíduos do grupo C1 (14.28 %) em relação ao grupo C2 (5.32 %). O ensaio C1 terminou com 70 % dos indivíduos prematuros, contrastando com a maioria dos indivíduos C2 em pós-desova. Em geral, os indivíduos continham níveis elevados de nutrientes nas gónadas. Quando o período de alimentação de cada ensaio chegou ao fim, os indivíduos dos grupos C1 e C2 foram induzidos artificialmente e duas experiências sequenciais foram realizadas: 1) desenvolvimento larvar e 2) ensaio de assentamento de modo a testar o efeito de três soluções indutoras da metamorfose SUP, GUS e SUW. As larvas obtidas através dos reprodutores C1, foram alimentadas com três dietas: 1) Rhodomonas baltica (Rho I), 2) Phaedactylum tricornutum (Phae) e 3) mistura de ambas as espécies (Mix I). As larvas alimentadas com dieta Rho I apresentaram uma sobrevivência favorável (15.56 %), rápido desenvolvimento larvar e atingiram competência aos 20 DPF. Neste grupo, observaram-se as taxas de metamorfose mais elevadas em SUP (46.67 %) e GUS (6.30 %) após 24h de exposição. As taxas de assentamento foram elevadas em SUW (1.98 %), após 48h de exposição. As larvas obtidas a partir dos reprodutores C2, foram submetidas a três dietas: 1) Rhodomonas baltica (Rho II), 2) Chaetoceros calcitrans (Chae) e 3) mistura de ambas as espécies (Mix II). As larvas alimentadas com a dieta Rho II, tiveram um rápido desenvolvimento e uma elevada sobrevivência foi observada na dieta Mix II (32.22 %). As taxas de metamorfose mais elevadas foram observadas nas larvas expostas a GUS (7.53 %). A utilização do biofilme pode ter ajudado a aumentar a metamorfose uma vez que pode representar uma fonte adicional de nutrientes. As taxas de assentamento foram maiores em GUS (10.25 %) e SUW (7.78 %). Os resultados obtidos mostraram que o fornecimento de dietas especificas contribuiu para o crescimento, sobrevivência e desenvolvimento das larvas de P. lividus. Além disso, os resultados sugeriram que o uso de soluções indutoras da metamorfose e assentamento possa contribuir para a sobrevivência das pós-larvas.