UNIVERSITÀ DEGLI STUDI DI SASSARI SCUOLA DI DOTTORATO DI RICERCA Scienze e Biotecnologie dei Sistemi Agrari e Forestali e delle Produzioni Alimentari Indirizzo Scienze e Tecnologie Zootecniche Ciclo XXVII The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) dr. Marco Giuseppe Pinna Direttore della Scuola prof. Antonello Cannas Referente di Indirizzo prof. Nicolò P.P. Macciotta Docente Guida dr. Antonio Pais Anno accademico 2013-2014 INDEX Abstract pag. 4 Chapter 1 General introduction 1.1 Introduction pag. 6 1.2 Description of the species pag. 12 1.3 Biology and habitats pag. 17 1.4 Density pag. 20 1.5 Reproductive cycle pag. 22 1.6 Growth pag. 24 1.7 Recruitment pag. 26 1.8 Fishing and commercial value of the sea urchin in Sardinia pag. 27 1.9 Interest for aquaculture pag. 30 1.10 Aim of the thesis pag. 31 1.11 References pag. 32 Chapter 2 Morphometric relationships and annual gonad index of Paracentrotus lividus from a coastal district of North western Sardinia 2.1 Introduction pag. 49 2.2 Materials and methods pag. 50 2.3 Results pag. 53 2.4 Discussion pag. 61 2.5 References pag. 64 1 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari Chapter 3 Laboratory rearing of Paracentrotus lividus juvenile specimens 3.1 Introduction pag. 71 3.2 Materials and methods pag. 73 3.2.1 Experiment at SAMS pag. 73 3.2.1.1 Sea urchins pag. 74 3.2.1.2 Biometrics and dissections pag. 76 3.2.1.3 Diet pag. 78 3.2.1.4 Experimental conditions and equipments pag. 79 3.2.1.5 Data analysis pag. 81 3.2.2 Experiment at the University of Sassari pag. 81 3.2.2.1 Sampling site and sampling design pag. 81 3.2.2.2 Sea urchins pag. 83 3.2.2.3 Biometrics, dissections and diet pag. 85 3.2.2.4 Experimental conditions and equipments pag. 85 3.2.2.5 Proximate composition pag. 88 3.2.2.6 Moisture and ash pag. 89 3.2.2.7 Crude protein pag. 90 3.2.2.8 Total lipids pag. 90 3.2.2.9 Acidic profile pag. 92 3.2.2.10 Data analysis pag. 93 3.3 Results pag. 93 3.3.1 SAMS experiment pag. 93 3.3.1.1 Survival and growth pag. 93 3.3.1.2 Dissections pag. 96 3.3.2 UNISS experiment pag. 102 2 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari 3.3.2.1 Survival and growth pag. 102 3.3.2.2 Dissections pag. 106 3.3.2.3 Proximate composition pag. 111 3.3.2.4 Fatty acids pag. 115 3.4 Discussion pag. 119 3.5 References pag. 125 Chapter 4 Profitability and sustainability of Paracentrotus lividus fishery in Sardinia 4.1 Introduction pag. 137 4.2 Materials and methods pag. 142 4.3 Results pag. 145 4.4 Discussion pag. 151 4.5 Conclusions pag. 154 4.6 References pag. 155 Acknowledgements pag. 160 3 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari Abstract In this study, several research approaches were used to increase the knowledge on the Mediterranean sea urchin Paracentrotus lividus. Morphometric characters and gonad indexes of sea urchin populations were monitored during one year to examine possible differences among seasons in 3 locations of Alghero Bay (NW Sardinia). Moreover, 2 experiments to test somatic growth, and gonad and alimentary indexes of laboratory-reared specimens fed an artificial diet were also carried out. The experiments lasted 16 and 10 weeks in Scotland and in Sardinia, respectively. In the latter, proximate composition and acidic profile of the sea urchins gonads were also assessed. Samples from natural populations were used as a control. Significant differences between reared and wild specimens were found, both regarding proximate composition (except for total lipids) and fatty acid profile. The results obtained confirm the effectiveness of the diet and rearing method used in enhancing sea urchins’ growth. Finally, an economical analysis on profitability and sustainability of P. lividus fisheries in Sardinia was performed. Firms operating with different harvesting methods were analysed, obtaining an overview of the current situation in terms of strengths and weaknesses of restrictions on the harvesting of this species. This information can be used by policy makers to implement important changes to the current fishing policy, by guaranteeing profitability for fishermen and conservation of wild stocks. 4 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari 1. General introduction 5 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari 1.1 Introduction Although water occupies more than 70% of the whole Earth crust, aquatic products satisfy just 1-2% of the humanity food requirement. Recent data by FAO (2012) shows an increase in fish products consumption that could bring into question the future of the aquatic resources which are continuously overexploited all over the world. The growth of fish production and the improvement of distribution channels in the past decades has increased the demand in consumption of fish food at an estimated growth rate of 3.2% per year from 1961 to 2009 (Sartori et al., 2015). According to what has been declared in such FAO report, human consumption of fish products is arrived at a level never reached before (about 17 kg per capita). Practically, in 2010, about 3 billions of people have satisfied at least 15% of their average protein needs just consuming aquatic foods. However, production resulting from seas, oceans and inland waters exploitation can’t be further increased from today’s levels, despite the demand for fish products is constantly greater than supplied and also continues its rise. Considering that the global population is estimated to grow until it reaches 9 billion people between 2040 and 2050 (UN, 2015), the collapse of natural resources, caused by the pressure on fish stocks, is a real problem (Sartori et al., 2015). In this scenario, aquaculture may have a dual and important role: on the one hand to ensure productions to meets the market demand (although still far from the required amounts), and on the other hand to allow a reduction of fishing pressure in strongly overexploited areas so as to promote a recovery of aquatic ecosystems, even if this will be a long and partial process. One of the factors contributing to the increasing demand for fish products is linked to the awareness of consumers about its excellent quality. Indeed, it is a food rich in proteins, vitamins and minerals in highly digestible form. Furthermore, thanks to the large amount of essential fatty acids, it is particularly suitable for the human diet. 6 Marco Giuseppe Pinna – The edible sea urchin Paracentrotus lividus (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central western Mediterranean) Tesi di dottorato in Scienze dei Sistemi Agrari e Forestali e delle Produzioni Alimentari, Indirizzo Scienze e Tecnologie Zootecniche, Università degli Studi di Sassari According to the last available statistics (FAO, 2014), the global aquaculture production in 2012 was of about 90 million tons, which means an estimate value of about 126 billion €. The whole of the fish and invertebrates production (almost 67 million tons) were destined entirely for human consumption, while the remaining (almost 23 million tons), mainly constituted by aquatic plants, was also used by several industries (i.e., chemicals, pharmaceuticals, cosmetics, food, etc.). Currently, 500 different aquatic species (both animals and plants) are farmed, but less than 10% are of a considerable economic value. Conversely, although some species play a leading role in some markets due to their high commercial value, the production of many of these (especially invertebrates) still shows a marginal and limited development. An example is provided by certain Echinoderms, in particular the sea urchins: due to the delicacies they represent in many countries around the world (Lawrence, 2007), also their farming practices have shown a continuous increase over time. However, the current demand for sea urchins (linked to the consumption of their gonads), is almost completely satisfied by harvesting activities from natural populations that, in various areas of the world, are often overexploited (as many other species) because inadequately managed and/or protected by effective regulation rules. Therefore, despite the trade of these Echinoids constitutes an extremely profitable business, the amount currently derived by aquaculture activities represents less than 1% of the total, compared to about 80,000 tons as a whole of sea urchins sold every year worldwide (Carboni et al., 2012).