Edible Sea Urchin Paracentrotus Lividus Research Articles

Intensive sea urchin harvest rescales Paracentrotus lividus population structure and threatens self-sustenance.

The harvest of the edible sea urchin Paracentrotus lividus is intensively practiced in some regions of the Western Mediterranean Sea. The removal of the largest individuals can determine an overall reduction in population size and a size class truncation that can lead to a drastic drop the self-sustenance. The aim of this study is to evaluate the variability of the population reproductive potential across 5 years in one of the main harvest hotspots of Sardinia (Western Mediterranean Sea). The breeding stock consists of commercial and under-commercial size individuals which were sampled on a monthly basis to estimate their GonadoSomatic Index (GSI) and the Individual Gamete Output (IGO). In addition, the reproductive potential of the population-Total Gamete Output (TGO)-was calculated across the 5-year period in relation with the variation of the density of the breeding stock. During the last year, the reproductive potential was also estimated in a well-conserved population of a nearby Marine Protected Area. No significant variability in GSI and IGO was found over the 5 years nor when compared with the ones of protected population in the last year. However, the intensive harvest drastically rescaled the population body-size: although density of the commercial size class remained low, density of the under-commercial size-class halved from the beginning to the end of the study. Accordingly, the proportional decrease of their gamete output contribution led to a 40% loss of the reproductive potential of the whole population in the 5-year period. Interestingly, despite the loss of reproductive potential due to the decrease of the breeding stock density, the average values of IGO slightly increased across the years leading to the highest Annual Gamete Output (AGO) during the fourth year of sampling. This positive pattern could suggest a mechanism of reproductive investments of the survivors in terms of gonad production rate or increase in spawning intensity. This work provides evidence of the direct effect of size-selective harvesting on the rapid loss of population self-sustenance. Furthermore, it lays new prospective for future research of the indirect effects of the rescaling population body-size in functional traits of the sea urchin P. lividus and that could become important for both, sustainable exploitation and ecosystem conservation management.

Handling, Reproducing and Cryopreserving Five European Sea Urchins (Echinodermata, Klein, 1778) for Biodiversity Conservation Purposes.

In this work, five local sea urchin species found in European waters were studied. Four were regular species: Sphaerechinus granularis, Psammechinus miliaris, Echinus esculentus (Linnaeus, 1758) and the edible sea urchin Paracentrotus lividus; and one was an irregular species, Echinocardium cordatum. These five species of sea urchins have been studied regarding their fertility, toxicity of cryoprotecting agents, cryopreservation of different cell types and chilling injury. The baseline fertility is similar in P. lividus, P. miliaris and S. granularis. Nonetheless, the sperm:egg ratio, contact time and development of the fertilization envelope would need to be studied further on a case-by-case basis. Sperm can be maintained inactively in the gonad (4 °C), and oocytes also maintain quality in sea water (4 °C), even after 72 h. Sperm was cryopreserved for four species with some post-thaw intra specific variability, and embryo cryopreservation was only possible for S. granularis. Overall, this study provided a wider vision of the biology and reproduction of these species that will help us develop tools for their biodiversity conservation through cryopreservation.

Biometric characteristics of the wild population of sea urchin Paracentrotus lividus (Lamarck, 1816) on the Tunisian coast

The present study was conducted to provide biometric data of the edible sea urchin Paracentrotus lividus along the Tunisian coastline where thirteen marine localities were selected randomly. A total of 653 individuals were collected and their metric and weight measurements were recorded. The size distribution of the different samples was determined and relative growth expressions were deduced. Data analysis showed that all localities’ samples of the wild population were dominated by one-size class, except Port Prince and Haouaria. Interestingly, only diameter-height relationships (D-H) were different between the geographical localities. Diameter-weight relationships (D-TW and D-TWTE) revealed a significant negative growth for all the localities, with the exception of Gammarth which showed positive growth for total weight (D-TW). Moreover, the multivariable analysis revealed divergences and/or similarities between metric and weight variables. Altogether, data highlights the inter-population discrimination with respect to geographic localization and clear segregation between the northern and the eastern localities demonstrated the plasticity of the species.

Impacts of Marine and Lagoon Aquaculture on Macrophytes in Mediterranean Benthic Ecosystems

The direct and indirect impact of fish farms, shellfish aquaculture, and extensive forms of aquaculture such as seeding of juvenile sea urchins, on macrophytes (seaweeds and seagrasses), is reviewed in Mediterranean benthic ecosystems. Fish farms constitute a source of organic matter and nutrients (food and fecal pellets) that causes the extirpation of Posidonia oceanica seagrass meadows beneath and near to farm facilities. In addition to direct effects, the nitrogen enrichment of macrophytes tissues increases the grazing pressure by herbivorous fishes and sea urchins. In some cases, the impact can continue to increase several years after the cessation of farming activities. Natural restoration of extirpated seagrass meadows is generally unlikely at the human time scale. Shellfish aquaculture is the cause of the main flow of introduced macrophytes in the Mediterranean; the main vector is the importation of oyster spat from Japan and Korea. North-eastern Pacific seaweeds are now the dominant biotic component of some Mediterranean lagoons (e.g., Thau, Mar Piccolo and Venice lagoons). In addition to direct effects, mussel aquaculture can constitute a source of larvae that flow with currents, the adults of which can overwhelm seaweed forests (e.g., Carpodesmia mediterranea). Shellfish aquaculture is also a source of fecal pellets, resulting in changes in bottom macrophytes, and a vector of diseases of metazoans, the extirpation of which may change the functioning of recipient macrophyte ecosystems. The edible sea urchin Paracentrotus lividus is sometimes erroneously considered as in decline due to over-harvesting. However, its abundance in the second half of the 20th century was probably a consequence of human impact (overfishing of its predatory fish, organic pollution. This man-induced proliferation resulted in the extirpation of seaweed forests (e.g., Carpodesmia spp., Treptacantha spp. – formerly Cystoseira spp. – Sargassum spp.; many species are endemic), which play a key role in Mediterranean coastal ecosystems. Therefore, the attempts to restore sea urchin abundance, via seeding of juveniles from hatcheries, has further artificialized the habitats rather than contributing to the restoration of natural ecosystems. Good practices guidelines are proposed aimed at minimizing the impact of aquaculture on macrophytes.

East to West: Population genòmics and hierarchical analyses reveal differential adaptation footprints in the edible sea urchin Paracentrotus lividus

East to West: Population genòmics and hierarchical analyses reveal differential adaptation footprints in the edible sea urchin Paracentrotus lividus

Hydrodynamic patterns favouring sea urchin recruitment in coastal areas: A Mediterranean study case

In invertebrate fisheries, sea urchin harvesting continues to grow with dramatic consequences for benthic ecosystems. The identification of areas with a marked natural recruitment and the mechanisms regulating it is crucial for the conservation of benthic communities and for planning the sustainable harvesting. This study evaluates the spatial distribution and density of recruits of the edible sea urchin Paracentrotus lividus along the Sinis + Peninsula (Sardinia) and explores its significant relationships with the local oceanographic features. Our results reveal that recruitment is favoured in areas with slow currents and high levels of confinement and trapping of the water masses. Analysis of the residual circulation indicates that the presence of local standing circulation structures promotes the sea urchin recruitment process. Our findings emphasize the importance of managing local sea urchin harvesting as a system of populations with their demographic influence mainly dependent on the most important ecological driver that is the recruitment.

Proteomic changes occurring along gonad maturation in the edible sea urchin Paracentrotus lividus

The reproductive stage of Paracentrotus lividus strongly influences product quality that, in turn, impacts significantly on the market price. Large, compact and sweet gonads are preferred, and sensory attributes are positively related to the ratio of nutritive phagocytes to gametes. Gonads at advanced maturation stages, although larger, have less desirable attributes, being more watery and bitter especially in females. Therefore, the best compromise among size, texture, and taste needs to be reached. In this study, wild P. lividus were collected along coastal Sardinia, and gonads in the recovery, pre-mature, mature, and spent stages were analyzed by gel-based and by shotgun proteomics. A detailed characterization of the proteome changes occurring in gonads of both sexes along maturation was achieved, and significant modifications were seen in numerous proteins involved in nutrient accumulation in nutritive phagocytes, as well as in gamete biology and maturation. Adding to an improved understanding of the P. lividus reproductive cycle in its natural environment, the results described in this work may form the basis for defining novel protein markers and procedures for an easier sexing and staging, and for monitoring sea urchin gonad maturation cycles in aquaculture plants. Mass spectrometry data are deposited in ProteomeXchange (PXD004200). SignificanceThe sensory quality of P. lividus gonads is strongly influenced by the reproductive cycle, with significant changes in flavor, texture, and size. A better knowledge of the protein profiles, patterns, and markers associated with gonad sex and maturation stage can have useful implications for understanding and monitoring these changes. One of these is the ability to identify protein profiles specifically associated with a given stage and, in perspective, to identify maturation and sex markers.The comprehensive proteomic evaluation achieved in this work was made possible by the application of combined gel-based and shotgun approaches. As a result, this study generated the largest proteomic dataset available in the literature for P. lividus, as well as a general picture of protein abundance changes occurring along maturation.

Influence of seasonal and environmental patterns on the lipid content and fatty acid profiles in gonads of the edible sea urchin Paracentrotus lividus from Sardinia

The influence of seasonal and environmental patterns on the lipid fraction of Paracentrotus lividus gonads was investigated. For this purpose, sea urchins were collected monthly over a year from two Sardinian coastal areas. Total lipids in gonads follow an annual cyclical trend, described by a sine wave curve, that it is more influenced by season than by growing area. The lowest lipid content in gonads corresponds to a high percentage of mature reproductive stages (i.e. winter season), independently of sampling area. A variation in total lipid content follows a change in photoperiod, while it is related to sea surface temperature. Multivariate analysis on fatty acid profiles of gonads, detected by gas chromatography, clusters the collected specimens mainly according to the sampling area, secondly according to the sites within the same sampling area and finally according to season.

Experimental Release of Juvenile Sea Urchins (Paracentrotus lividus) in Exploited Sites along the French Mediterranean Coast

ABSTRACT During the past 40 y, natural stocks of the edible sea urchin Paracentrotus lividus have declined sharply in many sites along the French Mediterranean coast. Despite current management measures, this resource remains at low densities, raising concerns among commercial fishermen and managers. The reseeding of depleted sea urchin populations is currently under consideration. In this study, a pilot-scale experiment was conducted to assess the feasibility of such an operation and to evaluate the impact on both the population structure and genetic diversity of wild communities. The genetic diversity and population differentiation of wild populations was assessed before reseeding five depleted populations with 250,000 hatchery-produced juveniles. A year after release, parentage assignment tests were performed on small recaptured sea urchins to address their origin. Sea urchins from the hatchery were found at two of five sites, representing 3% and 12% of the total recaptured urchins in the concerned sit...

Ultrastructural and biochemical characterization of mechanically adaptable collagenous structures in the edible sea urchin Paracentrotus lividus

The viscoelastic properties of vertebrate connective tissues rarely undergo significant changes within physiological timescales, the only major exception being the reversible destiffening of the mammalian uterine cervix at the end of pregnancy. In contrast to this, the connective tissues of echinoderms (sea urchins, starfish, sea cucumbers, etc.) can switch reversibly between stiff and compliant conditions in timescales of around a second to minutes. Elucidation of the molecular mechanism underlying such mutability has implications for the zoological, ecological and evolutionary field. Important information could also arise for veterinary and biomedical sciences, particularly regarding the pathological plasticization or stiffening of connective tissue structures. In the present investigation we analyzed aspects of the ultrastructure and biochemistry in two representative models, the compass depressor ligament and the peristomial membrane of the edible sea urchin Paracentrotus lividus, compared in three different mechanical states. The results provide further evidence that the mechanical adaptability of echinoderm connective tissues does not necessarily imply changes in the collagen fibrils themselves. The higher glycosaminoglycan (GAG) content registered in the peristomial membrane with respect to the compass depressor ligament suggests a diverse role of these molecules in the two mutable collagenous tissues. The possible involvement of GAG in the mutability phenomenon will need further clarification. During the shift from a compliant to a standard condition, significant changes in GAG content were detected only in the compass depressor ligament. Similarities in terms of ultrastructure (collagen fibrillar assembling) and biochemistry (two alpha chains) were found between the two models and mammalian collagen. Nevertheless, differences in collagen immunoreactivity, alpha chain migration on SDS-PAGE and BLAST alignment highlighted the uniqueness of sea urchin collagen with respect to mammalian collagen.

Production, characterization and biocompatibility of marine collagen matrices from an alternative and sustainable source: the sea urchin Paracentrotus lividus.

Collagen has become a key-molecule in cell culture studies and in the tissue engineering field. Industrially, the principal sources of collagen are calf skin and bones which, however, could be associated to risks of serious disease transmission. In fact, collagen derived from alternative and riskless sources is required, and marine organisms are among the safest and recently exploited ones. Sea urchins possess a circular area of soft tissue surrounding the mouth, the peristomial membrane (PM), mainly composed by mammalian-like collagen. The PM of the edible sea urchin Paracentrotus lividus therefore represents a potential unexploited collagen source, easily obtainable as a food industry waste product. Our results demonstrate that it is possible to extract native collagen fibrils from the PM and produce suitable substrates for in vitro system. The obtained matrices appear as a homogeneous fibrillar network (mean fibril diameter 30–400 nm and mesh < 2 μm) and display remarkable mechanical properties in term of stiffness (146 ± 48 MPa) and viscosity (60.98 ± 52.07 GPa·s). In vitro tests with horse pbMSC show a good biocompatibility in terms of overall cell growth. The obtained results indicate that the sea urchin P. lividus can be a valuable low-cost collagen source for mechanically resistant biomedical devices.

Reproductive Cycle of the Edible Sea Urchin Paracentrotus lividus (Lamarck, 1816) (Echinodermata: Echinoidea) in the Coastal Region El Jadida-Safi (Atlantic Ocean, Morocco)

Reproductive Cycle of the Edible Sea Urchin Paracentrotus lividus (Lamarck, 1816) (Echinodermata: Echinoidea) in the Coastal Region El Jadida-Safi (Atlantic Ocean, Morocco) The Sea urchins populations of P. lividus had an annual reproductive cycle that was synchronous across sites and between males and females. The histology of the gonads revealed six different stages: Recovering, Growing, Premature, Mature, Partly spawned and Spent. Maturation occurred between March and late April while spawning period occurred in May and early August with little difference between sites. The Gonad indices showed a peak from late winter to early spring. A perfect correlation observed between the gonad index and the histological results suggests that the gonad index decreases when the individual is spawning. Nevertheless, the GI seems to be influenced by abiotic factors particularly sea water temperature in the first station (Sidi Bouzid) and the food richness of the environment in the second station (Ain Darak).

Primary cell cultures from sea urchin ovaries: a new experimental tool

In the present work, primary cell cultures from ovaries of the edible sea urchin Paracentrotus lividus were developed in order to provide a simple and versatile experimental tool for researches in echinoderm reproductive biology. Ovary cell phenotypes were identified and characterized by different microscopic techniques. Although cell cultures could be produced from ovaries at all stages of maturation, the cells appeared healthier and viable, displaying a higher survival rate, when ovaries at early stages of gametogenesis were used. In terms of culture medium, ovarian cells were successfully cultured in modified Leibovitz-15 medium, whereas poor results were obtained in minimum essential medium Eagle and medium 199. Different substrates were tested, but ovarian cells completely adhered only on poly-L-lysine. To improve in vitro conditions and stimulate cell proliferation, different serum-supplements were tested. Fetal calf serum and an originally developed pluteus extract were detrimental to cell survival, apparently accelerating processes of cell death. In contrast, cells cultured with sea urchin egg extract appeared larger and healthier, displaying an increased longevity that allowed maintaining them for up to 1 month. Overall, our study provides new experimental bases and procedures for producing successfully long-term primary cell cultures from sea urchin ovaries offering a good potential to study echinoid oogenesis in a controlled system and to investigate different aspects of echinoderm endocrinology and reproductive biology.

Hydrodynamism and its influence on the reproductive condition of the edible sea urchin Paracentrotus lividus

Despite the large body of work published in the last two decades on the reproduction of the sea urchin Paracentrotus lividus, the reproductive aspects linked to hydrodynamic conditions and their influence on gonad production remain poorly understood. The present paper aims to evaluate the effect of hydrodynamism on the reproductive cycle of P. lividus. Variability in the gonadosomatic index (GSI) of P. lividus was estimated seasonally from 2007 to 2008 at two shallow sub-littoral flat basaltic areas at Ustica Island (Western Mediterranean). GSI was higher in the sites characterized by low hydrodynamism than in those with high hydrodynamism. Results also suggest a possible role for hydrodynamism in triggering processes of resource limitation (food shortage), probably by interfering with P. lividus feeding activity.

In situ spine sampling and Inter-Simple Sequence Repeat (ISSR) PCRs proved relevant methods for molecular studies on the sea urchin Paracentrotus lividus

In France, there are raising concerns about the edible sea urchin Paracentrotus lividus, whose populations decline. In this context, molecular analyses contribute to the better understanding of processes that shape populations, which is required to adapt management and conservation programmes. The present study aimed at developing an in situ non-destructive spine sampling method and an ISSR-PCR approach, both dedicated to the genetic analysis of individuals and populations. Forty-five individuals of 3 close populations were studied. In situ spine sampling proved relevant, leading to the clear genotyping of all purified DNAs without any contamination. Molecular analysis revealed high genetic diversity with a large proportion of low-frequency ISSR markers. Six ISSR primers produced 154 scorable polymorphic markers of which 118 (77%) were present at a frequency lower than 25%. Based on genotyping profiles obtained with 3 ISSR primers, significant genetic differentiation between the studied populations was detected. Taken together, these results revealed that both in situ spine sampling and ISSR method are relevant for molecular analyses and that they will likely find their application in future conservation and management programmes.

Harvesting Effects on Paracentrotus lividus Population Structure: A Case Study from Northwestern Sardinia, Italy, before and after the Fishing Season

Abstract PAIS, A.; SERRA, S.; MELONI, G.; SABA, S., and CECCHERELLI, G., 2012. Harvesting effects on Paracentrotus lividus population structure: A case study from northwestern Sardinia, Italy, before and after the fishing season. The edible sea urchin Paracentrotus lividus is commercially exploited in many European countries. In recent years, however, its stocks have shown a large reduction in several regions because of overfishing. This paper reports the effects of harvesting on P. lividus population structure in shallow rocky reefs from a central-western Mediterranean area where this activity is intensively practiced. Density, size (test diam), and biomass of sea urchin were assessed in October 2004 (just before the fishing season) and in May 2005 (immediately after the fishing season) at two locations where intense P. lividus harvest occurs and at two controls within an adjacent Marine Protected Area (MPA) where P. lividus harvest is prohibited. Density, size, and average biomass of P. lividus were sig...

The operational sex ratio of the sea urchin Paracentrotus lividus populations: the case of the Mediterranean marine protected area of Ustica Island (Tyrrhenian Sea, Italy)

AbstractWe investigated, with a series of field and laboratory observations, the possible effect of the starfish Marthasteria glacialis predation on the operational sex ratio (OSR), i.e. the number of sexually mature males divided by the total number of sexually mature adults of both sexes at any one time, of the edible sea urchin Paracentrotus lividus. The OSR was estimated three times during the sea urchin summer spawning period (July 2004, June 2005 and July 2006) on barren substrates of Ustica Island Marine Protected Area (Southern Tyrrhenian Sea, Italy). Four sites were selected: two characterized by high M. glacialis density (take zone C) and two controls with low starfish density (no‐take zone A). Mature sea urchins were independently collected by SCUBA diving and sexed. The adult sex ratio was skewed towards males at high M. glacialis density sites, whereas it was balanced (1:1) at predator low‐density sites. Results of sex‐selective feeding experiments in the laboratory showed that females of P. lividus were more vulnerable to M. glacialis predation. These outcomes underline the possible importance of M. glacialis in regulating the OSR of P. lividus populations.

The impact of commercial and recreational harvesting for Paracentrotus lividus on shallow rocky reef sea urchin communities in North-western Sardinia, Italy

The fishery for the edible sea urchin Paracentrotus lividus is of great importance to many European regions, although in some of them this species has shown a wide scale decline in recent years. This paper reports on direct (on P. lividus) and indirect (on the co-occurring but not fished echinoid, Arbacia lixula) effects of sea urchin harvesting in shallow rocky reefs in North-western Sardinia (Italy, central-western Mediterranean Sea), where this activity is intensively practised. Density, size (test diameter), and biomass of both species were assessed in autumn 2004 at two locations impacted by P. lividus fishery, and at two controls within an adjacent Marine Protected Area. Density of P. lividus and A. lixula was significantly greater at the controls than at the exploited locations. The average test diameter of P. lividus was also significantly larger at the controls, where large-sized specimens (i.e. >5 cm) were notably more abundant. The average size of A. lixula did not significantly differ between the impacted locations and the controls. The average biomass of P. lividus was significantly greater at the controls than at the exploited locations, whereas no differences were detected for A. lixula. These results reveal the existence of a heavy fishing impact on P. lividus in North-western Sardinia and the need for regulation of its harvesting to prevent severe direct effects on its populations. Since no indirect effects on A. lixula have been detected, it could be hypothesized that this species did not benefit from P. lividus fishery due to an only moderate competition for habitat and resources between these two echinoids. Implications for management of edible sea urchin fishery are also discussed.

Determination of carotenoids and liposoluble vitamins in sea urchin (Paracentrotus lividus) by high performance liquid chromatography

High-performance liquid chromatography was used to determine carotenoids (lutein, β-carotene, β-isocryptoxanthin, and β-echinenone) and liposoluble vitamins (retinol=vitamin A, and α-tocopherol=vitamin E) in fresh and canned gonads of the edible sea urchin Paracentrotus lividus. β-Carotene, β-isocryptoxanthin, and β-echinenone are vitamin A precursors. The carotenoids were determined with UV–vis detection and the vitamins with fluorescence detection. The sensitivity and precision of the method were good. Retinol was not detected in either fresh or canned material. Mean concentrations in fresh material (mg per 100 g dry weight) were 3.44 for lutein, 0.79 for β-carotene, 1.89 for β-isocryptoxanthin, 11.35 for β-echinenone, and 7.86 for α-tocopherol. Mean concentrations in canned material were 70–80% of concentrations in fresh material, except for β-echinenone, the concentration of which was about 30% higher in canned material.

Microstructure adaptative des radioles deParacentrotus lividus (Echinodermata: Echinoidea) en milieu eutrophis� par des eaux us�es

Recent investigations (1984) on the biology and morphometry of populations of the edible sea-urchinParacentrotus lividus (Lamarck) exposed to massive domestic pollution from the Cortiou sewage outlet (Marseille, France), revealed a significant lengthening of sea-urchin spines at sites located at a distance of 500m (Station 0) and 1 200 m (Station 1) from the outlet. At Station 0, spine length (SL) is nearly half as long as the diameter (D) of the test, resulting in a higher SL:D ratio here-0.470 as opposed to 0.360 in unpolluted areas (e.g. Station 3, 5 200 m from the outlet). This spine lengthening appears to be a morphofunctional adaptation, enabling the sea-urchins to adopt sestonophagy in order to benefit better from the plentiful resources of both particulate and dissolved organic matter arising from the outfall; examination of pellets filling the stomachs and guts of the sea-urchins corroborated this. SEM examination revealed that spines of specimens collected at Station 0 are more “porous” than those from Station 3 and their microarchitecture is better adapted to capturing suspended particulate matter: the ridges are narrower, the grooves wider, and the latter display a dense and more coarsely-meshed network. The axial medulla exhibits true and regularly arranged channels with highly structured walls. The ratio dry wt of spine: dry wt of test revealed thatP. lividus spines from Station 0 (ratio= 1.2) are lighter than those from Station 3 (ratio=1.4), reflecting the more porous microstructure and lighter stereome of the Station 0 sea-urchins. Previous measurements to determine the degree of eutrophication in the area polluted by the Marseilles urban sewage outfall revealed carbon content, as % of total sediment, as high as 36% in newly deposited sediment (100 m from the outlet), 16.7% at Station 0 (500 m) and 2.6% near Station 3 (about 5 200 m). Further experiments using sediment traps indicated that the organic matter tends to accumulate chiefly along the shoreline, whereas the suspended mineral fraction tends to be deposited to the south, i.e., further offshore. Thus, theP. lividus population at Station 0 exhibits a very unusual ecological plasticity, having developed a very efficient adaptative microstructure in order to meet its energy requirements despite the presence of various chemical pollutants.