Sparidae E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1020

Veröffentlichungsjahr: 2011

Beschreibung

The Sparidae, commonly known as breams and porgies, is a family of fishes of the order Perciformes, and includes about 115 species of mainly marine coastal fish of high economic value, exploited and farmed for human consumption, as well as for recreational purposes. This landmark publication brings together a huge wealth of information on the biology and culture of gilthead sea bream and other Sparidae species. Commencing with an overview of the current status of aquaculture of Sparidae, the book continues with comprehensive coverage of the family's phylogeny, evolution and taxonomy, stress and welfare issues, and reproduction and broodstock management. Further chapters include coverage of early development and metabolism, production systems, nutrition, quality, and health management. A final cutting-edge chapter looks at genomic-proteomic research in Sparidae and its application to genetic improvement. With contributions from Europe, the Middle East, Asia, Australasia and North America, carefully drawn together and edited by Professor M. Pavlidis and Dr C. C. Mylonas, themselves well known for their work in this area, Sparidae is an essential purchase for anyone working with this important family of fishes. Fish biologists, fish farmers, aquaculture researchers, and fisheries managers will all find much of great use and interest within this book's covers. All universities and research establishments where biological sciences, aquaculture and fisheries science are studied and taught should have copies of this excellent book on their shelves.

Leseprobe

Contents

Cover

Title Page

Copyright

Preface

List of Contributors

Chapter 1: Current status of Sparidae aquaculture

1.1 Introduction

1.2 World Sparidae production

1.3 Aquaculture status of Atlantic-Mediterranean species

1.4 Aquaculture status of Indo-Pacific species

References

Chapter 2: Phylogeny, evolution, and taxonomy of sparids with some notes on their ecology and biology

2.1 The position of the Sparidae in the fish tree of life

2.2 Fossil record

2.3 The monophyly of the Sparidae

2.4 Intrafamiliar relationships

2.5 Larval taxonomy and systematics

2.6 Biogeography

2.7 Biology

2.8 Conclusions

Acknowledgments

References

Chapter 3: Stress and welfare in sparid fishes

3.1 Introduction

3.2 Fish stress and fish welfare

3.3 The physiology of the stress response

3.4 Stress indicators

3.5 Responses to stressors in sparids

3.6 Aquaculture and fish welfare

3.7 Prospects of welfare research in aquaculture

3.8 Conclusions

References

Chapter 4: Reproduction and broodstock management

4.1 Introduction

4.2 Hermaphroditism and puberty in Sparidae

4.3 Reproductive cycles in Sparidae

4.4 Reproductive behavior and spawning in Sparidae

4.5 Broodstock management in Sparidae

4.6 Hormonal manipulation of reproduction in Sparidae

References

Chapter 5: Early development and metabolism

5.1 Introduction

5.2 Anatomical development, general characteristics, and sensory organs

5.3 Organogenesis and functionality of digestive system

5.4 Growth and energetics

5.5 Larval nutrition

5.6 Feeding

5.7 Conclusion

Acknowledgments

References

Chapter 6: Production systems

6.1 Introduction

6.2 Hatchery and nursery for fingerlings production

6.3 Cage culture growout technologies

6.4 Land-based production systems

6.5 Ongrowing metabolic rates

6.6 Water quality requirements and environmental conditions

6.7 Environmental aspects of production systems

6.8 Summary and future directions

References

Chapter 7: Nutrition and feeding of Sparidae

7.1 Introduction

7.2 Nutritional requirements of juveniles: protein and amino acids

7.3 Energy and protein requirements in gilthead sea bream—factorial approach

7.4 Lipids

7.5 Carbohydrates

7.6 Vitamins

7.7 Minerals

7.8 Alternative dietary protein and lipid sources

7.9 Final considerations

References

Chapter 8: Skeletal deformities and juvenile quality

8.1 Introduction

8.2 Morpho-functional ontogenesis in Sparidae

8.3 Skeletal deformities in reared Sparidae

8.4 Other developmental anomalies

8.5 Effects of deformities on fish performance and quality

8.6 Causative factors of skeletal deformities

8.7 Discussion and conclusions

References

Chapter 9: Pigmentation physiology and discoloration problems

9.1 Introduction

9.2 Basis of skin color

9.3 Biochemistry of melanin and carotenoids

9.4 Morphological and physiological skin color changes

9.5 Regulation of skin color

9.6 Improvement of skin color in intensively reared Sparidae

9.7 Conclusions

References

Chapter 10: Diseases and health management

10.1 Viral diseases

10.2 Bacterial diseases

10.3 Fungal diseases

10.4 Parasites and parasitic diseases

10.5 Noninfectious diseases and multifactorial diseases

References

Chapter 11: Genomic–proteomic research in Sparidae and its application to genetic improvement

11.1 Introduction

11.2 Selective breeding, quantitative trait, loci identification, and application

11.3 Genomic research

11.4 Proteomic research

11.5 Conclusions and future perspectives

Acknowledgments

References

Color Plate

Index

This edition first published 2011 © 2011 by Blackwell Publishing Ltd. Chapter 1 © FAO. The views expressed in this chapter are those of the authors and do not necessarily reflect the views of the Food and Agriculture Organization of the United Nations (FAO).

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Library of Congress Cataloging-in-Publication Data

Sparidae : biology and aquaculture of gilthead sea bream and other species / edited by Michalis Pavlidis, Constantinos Mylonas. p. cm. Includes bibliographical references and index. ISBN 978-1-4051-9772-4 (hardcover : alk. paper) 1. Sparidae. I. Pavlidis, Michalis. II. Mylonas, Constantinos. QL638.S74S63 2011 639.3′772–dc22 2010027338

A catalogue record for this book is available from the British Library.

This book is published in the following electronic formats: ePDF 9781444392197; Wiley Online Library 9781444392210; ePub (9781444392203)

Preface

The family of Sparidae—sea breams and porgies—is a moderately sized but morphologically and ecologically highly diverse family of percoid fishes. Sparids are widely distributed, highly appreciated and of commercial significance for both fisheries and aquaculture in many areas around the world. The history of red sea bream (Pagrus major) aquaculture in Japan is the oldest among marine fishes, while the domestication of gilthead sea bream (Sparus aurata) that started in Europe in the 1970s resulted in the development of a large-scale industry in the Mediterranean region, and beyond. Fueled by the interest in their cultivation, sparid fishes have been used as models in studying various aspects of fish biology. For example, a large body of basic research produced significant knowledge in the area of reproduction, especially in the area of hermaphroditism that is a major characteristic of the Sparidae family. This book aims to gather, for the first time, the published information in one volume, by presenting the current knowledge in the evolution, biology, physiology, and culture of sparid fishes, drawing heavily in some parts from the extensive research undertaken with the gilthead sea bream. The book covers both generic aspects and main production obstacles in the currently cultured species, and it is organized with a balance in mind between basic and applied aspects of Sparidae biology and farming. It is targeted toward fish biologists and aquaculture professionals, as well as stakeholders involved in fisheries management and aquaculture. It will also be a useful reference for students enrolling in the field of aquaculture and management of marine resources.

The book begins with coverage of the status of fisheries and aquaculture production of the most economically valuable sparids and includes a chapter on the phylogeny, evolution, and taxonomy also of species that are not necessarily of interest to the aquaculture industry. Throughout the book, basic biology information intertwines with applied aspects of aquaculture production, in an effort not only to better understand the biology of these fishes but also to enhance and optimize the husbandry methods and production efficiency of the aquaculture industry. A thorough coverage is provided on aspects of reproduction and broodstock management; early development and metabolism, and nutrition and feeding in culture conditions; and pigmentation physiology and discoloration problems in captivity, since the color of some sparid fishes is an important recognition criterion for the consumer. More directly related to the aquaculture environment are the chapters providing information on production systems, skeletal deformities, stress physiology and welfare, and diseases and health management. Understanding the need to fully “domesticate” the sparid species under culture today and the role that selective breeding programs must play in the improvement in production efficiency of the aquaculture industry, the final chapter deals with genetic improvement in and genomic–proteomic research on members of the Sparidae, with emphasis on the gilthead sea bream.

We would like to express our thanks to the authors of the various chapters who gave us their time, ideas, and knowledge to develop this book. We are also grateful to many amateur or professional photographers for giving us permission to reprint pictures of various sparids in the wild or captivity. Finally, we would like to thank various colleagues, students, and aquaculture professionals for challenging us with puzzling questions, alternative views, and suggestions for production and research priorities, all of which have contributed to our decision to endeavor in the production of this book on “Sparidae: Biology and Aquaculture of Gilthead Sea Bream and Other Species.”

List of Contributors

Kohsuke Adachi

Laboratory of Aquatic Product Utilization, Graduate School of Agriculture, Kochi University, Monobeotsu 200, Nankoku, Kochi 783-8502, Japan. E-mail: HYPERLINK “mailto:[email protected]”

Liliana Anjos

Centro de Ciencias do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. E-mail: [email protected]

Bernardo Basurco

Mediterranean Agronomic Institute of Zaragoza (IAMZ), International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM), Avenida de Montañana 1005, 50059 Zaragoza, Spain. E-mail: [email protected]

Stephen Battaglene

Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Hobart, Tasmania 7001, Australia, 7001. E-mail: [email protected]

Amal Biswas

Fisheries Laboratory, Kinki University, Uragami 468-3, Nachikatsuura, Wakayama 649-5145, Japan. E-mail: [email protected]

Clara Boglione

Laboratory of Experimental Ecology and Aquaculture, Biology Department, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy. E-mail: [email protected]

João C.R. Cardoso

Centro de Ciencias do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. Email: [email protected]

Stavros Chatzifotis

Hellenic Center for Marine Research, Institute of Aquaculture, PO Box 2214, Heraklion 71003, Crete, Greece. E-mail: [email protected]

Angelo Colorni

Israel Oceanographic and Limnological Research, National Center for Mariculture, PO Box 1212, Eilat 88112, Israel. E-mail: [email protected]

Luis E.C. Conceição

Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, P-8005-139 Faro, Portugal. E-mail: [email protected]

Corrado Costa

Agricultural Engineering Research Unit of the Agriculture Research Council (CRA-ING), Via della Pascolare 16, 00016 Monterotondo (Rome), Italy. E-mail: [email protected]

Hiroshi Fushimi

Department of Marine Biotechnology, Faculty of Life Science and Biotechnology, Fukuyama University, 452-10 Innoshima Ohama, Onomichi, Hiroshima 722-2101, Japan. E-mail: [email protected]

Benjamin García

IMIDA-Acuicultura, Consejería de Agricultura y Agua de la Región de Murcia, Puerto de San Pedro del Pinatar, 30740 San Pedro del Pinatar, Murcia, Spain. E-mail: [email protected]

Reinhold Hanel

Institute of Fisheries Ecology, Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries, Palmaille 9, 22767 Hamburg, Germany. E-mail: [email protected]

Ross Houston

The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin Biocentre, Roslin EH25 9PS, United Kingdom. E-mail: [email protected]

Hirohiko Kagawa

Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan. E-mail: [email protected]

Tomonari Kotani

Faculty of Fisheries, Kagoshima University, Shimoarata 4-50-20, Kagoshima, Kagoshima 890-0056, Japan. E-mail: [email protected]

Bruno Louro

Centro de Ciencias do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; and The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin Biocentre, Roslin EH25 9PS, United Kingdom. E-mail: [email protected]

Alessandro Lovatelli

Food and Agriculture Organization (FAO), Fisheries and Aquaculture Department, Aquaculture Service, Viale delle Terme di Caracalla, 00153 Rome, Italy. E-mail: [email protected]

Ingrid Lupatsch

Centre for Sustainable Aquaculture Research, University of Swansea, Singleton Park, Swansea, SA2 8PP, United Kingdom. E-mail: [email protected]

Noam Mozes

Israel Oceanographic & Limnological Research, National Center for Mariculture, PO Box 1212, Eilat, Israel. E-mail: [email protected]

Constantinos C. Mylonas

Hellenic Center for Marine Research, Institute of Aquaculture, PO Box 2214, Heraklion 71003, Crete, Greece. E-mail: [email protected]

Ioannis Nengas

Hellenic Centre for Marine Research, Institute of Aquaculture, Laboratory of Fish Nutrition and Pathology, Agios Kosmas, Hellinikon 16777, Athens, Greece. E-mail: [email protected]

Andreas Ntatsopoulos

FORKYS, S.A., Ag. Isidorou 15, 82200, Chios, Greece. E-mail: [email protected]

Francesc Padrós

Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Cerdanyola del Vallès, Spain. E-mail: [email protected]

Ned Pankhurst

Australian Rivers Institute, Griffith University, Gold Coast Campus, Queensland 4222, Australia. E-mail: [email protected]

Nikos Papandroulakis

Hellenic Center for Marine Research, Institute of Aquaculture, PO Box 2214, Heraklion 71003, Crete, Greece. E-mail: [email protected]

Michail A. Pavlidis

Department of Biology, University of Crete, PO Box 2208, Heraklion 71409, Crete, Greece. E-mail: [email protected]

Deborah M. Power

Centro de Ciencias do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. E-mail: [email protected]

Kenji Takii

Fisheries Laboratories, Kinki University, Uragami 468-3, Nachikatuura, Wakayama 649-5145, Japan. E-mail: [email protected]

Aires Oliva Teles

Centro Interdisciplinar de Investigação Marinha e Ambiental (CIMAR/CIIMAR), Universidade do Porto, Porto, and Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002 Porto, Portugal. E-mail: [email protected]

Lluis Tort

Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona and Xarxa de Referencia en Aqüicultura de Catalunya, 08193 Cerdanyola, Spain. E-mail: [email protected]

Costas S. Tsigenopoulos

Hellenic Centre for Marine Research, Institute of Marine Biology and Genetics, Crete, PO Box 2214, Heraklion 71003, Crete, Greece. E-mail: [email protected]

Jose Manuel Vergara

Biology Department, University of Las Palmas de Gran Canaria, PO Box 35017, Las Palmas de Gran Canaria, Canary Islands, Spain. E-mail: [email protected]

Norman Y.S. Woo

Department of Biology, The Chinese University of Hong Kong, Hong Kong SAR, China. E-mail: [email protected]

Manuel Yúfera

Instituto de Ciencias Marinas de Andalucía (CSIC), Apartado Oficial, E-11510 Puerto Real, Cádiz, Spain. E-mail: [email protected]

Yonathan Zohar

Department of Marine Biotechnology, University of Maryland, Baltimore County, 701 E. Pratt St., Baltimore, MD 21202, USA. E-mail: [email protected]

Chapter 1

Current status of Sparidae aquaculture

Bernardo Basurco, Alessandro Lovatelli, and Benjamin García

1.1 Introduction

1.2 World Sparidae production

1.3 Aquaculture status of Atlantic-Mediterranean species

1.4 Aquaculture status of Indo-Pacific species

References

Abstract: The Sparidae, commonly called breams and porgies, is a family of the order Perciformes and includes about 115 species, mainly marine coastal fish, of high economic value, exploited and farmed for human consumption, as well as for recreational purposes. In terms of aquaculture, the Sparidae production in 2006 accounted for 244,153 mtn, and represented 6.8% of the volume and 14.5% of the value of the production of Percoidei fishes (a suborder including the tilapias, breams, seabasses, groupers, etc.). Although the UN Food and Agriculture Organization (FAO) aquaculture statistics compiles data for about 20 Sparidae species—some of them with discontinued records of production—more than 75% of the production is referred to just two species, the gilthead sea bream (Sparus aurata, 107,620 mtn) cultured mainly in the Mediterranean Sea, and the red sea bream (Pagrus major, 75,754 mtn) cultured in the Asia-Pacific region. The present chapter is an updated review of the characteristics of the main aquacultured species, the production cycle, and the production volume of all species with FAO statistics records. A special emphasis is given in the gilthead sea bream farming sector, because it is the Sparid that has shown the fastest and most significant growth during the last two decades. A comparative economic analysis on the ongrowing of several Atlantic-Mediterranean species is also presented.

Key words: aquaculture production; breams; Sparidae; sparids

1.1 Introduction

The Sparidae family, commonly called breams and porgies, belongs to the order Perciformes. The Perciformes (perch-likes fishes) is the largest order of fishes, and its classification is still unsettled today and is a subject of considerable research. The Perciformes consist of 20 suborders, 160 families, about 1540 genera and over 10,000 species. Some 52 families have a single genus, 23 have a single species, and 21 have 100 or more species (Nelson 2006). The Perciforms are found mainly in marine shore waters, although some species (e.g., cichlids) normally live only in freshwater, and about 2335 species live in freshwater for at least part of their life history (Nelson 2006). The Percoidei is the largest of the 20 suborders of the Perciformes and contains 79 families—including the Sparidae, 540 genera, and about 3176 species (Nelson 2006).

The world capture-fisheries of the Percoidei suborder in 2006 was 11,623,304 mtn (FAO-FishStatPlus 2008). In the same year, the global fish aquaculture production was 32,613,021 mtn. In terms of aquaculture, Percoidei represented 11% of the total output with a production of 3,585,396 mtn. This group of fish contributes most to world aquaculture production after the Cypriniformes (63%) and followed by the Salmoniformes (7%). Most commercially harvested and farmed fish species belong to the Percoidei suborder, including the tilapias, breams and porgies, sea basses, amberjacks, groupers, barramundi, cobia, perches, etc. (Table 1.1). As for the Percoidei aquaculture production, the Cichlidae family (tilapias) contributed 65% of the volume produced, while the Sparidae family, which ranked third, contributed 6.8% in volume and 14.5% in value, with a production of 244,153 mtn.

Table 1.1 Word aquaculture production of Percoidei fishes by families in 2006

Source: From FAO-FishStatPlus (2008). “nei” means not elsewhere included.

The family Sparidae includes a large number of species of high economic value, exploited and farmed for human consumption, and fished also for recreational purposes. This family has about 115 species classified in 33 genera (Nelson 2006), although according to FishBase (updated November 22, 2004) the family has 127 species and subspecies. Based on the dentition and diet, the Sparidae family has been traditionally divided into three subfamilies (Tortonese 1975). However, the classification of these species remains unclear, as some inconsistencies between morphological and molecular data have been described. Thus, molecular phylogeny analysis has suggested that Sparidae are divided into six subfamilies: Boopsinae, Denticinae, Diplodinae, Pagellinae, Pagrinae, and Sparinae (Orrell et al. 2002; Nelson 2006).

The Sparidae are mainly marine coastal fish, less frequent in fresh or brackish waters. They have a wide distribution, from tropical to temperate waters, and are found in the Atlantic, Indian, and Pacific Oceans, and the Mediterranean Sea. They are demersal inhabitants of the continental shelf and slope. Occasionally, they are found in estuaries, which are used as nursery grounds (Carpenter & Niem 2001). Sparidae species are physically characterized by an oblong body, moderately deep and compressed (maximum size of 75 cm), with a large head profile often with a steep upper profile, regularly curved with a maxilla hidden by a sheath when the mouth is closed (Carpenter & Niem 2001). They have 24 vertebrae and a single dorsal fin, usually with 10–13 spines, and three spines in the anal fin. Their overall color is highly variable, from pinkish or reddish to yellowish or greyish, often with silvery or golden reflections, and dark or colored spots, stripes, or bars. Most Sparidae are carnivores and feed on benthic invertebrates. Many species have been found to be hermaphroditic, some have male and female gonads simultaneously, while others change sex as they get larger.

1.2 World Sparidae production

The total Sparidae production was 693,732 mtn in 2006 (FAO-FishStatPlus 2008), with 65% of the production coming from capture fisheries (449,579 mtn) and the remaining 35% (244,153 mtn) from aquaculture (Figure 1.1). The FAO capture fisheries production records present data for 45 species. However, about 55% of the capture production (244,870 mtn) is generally reported as “Porgies, sea bream nei,”1 without the species being identified. Four other species entries have a recorded production over 10,000 mtn (Bogue, Boops boops; silver sea bream—red sea bream2 and Australian snapper—Pagrus auratus; Dentex, Dentex spp. and Pandora, Pagellus bellottii) and the remaining 40 entries have smaller productions.

Figure 1.1 Evolution of world Sparidae capture and aquaculture production in mtn.

In terms of aquaculture, the first FAO production statistics come from Japan with one tonne produced in 1958 of red sea bream (Pagrus major). The first recorded data for the gilthead sea bream (Sparus aurata) refers to Italy in 1970. Since then, more Sparidae species have been farmed—although some have now been discontinued—with production records for the following 19 FAO species entries: blackhead sea bream (Acanthopagrus schlegeli), blackspot (= red) sea bream (Pagellus bogaraveo), common dentex (Dentex dentex), common pandora (Pagellus erythrinus), common two-banded sea bream (Diplodus vulgaris), crimson sea bream (Evynnis japonica), gilthead sea bream (Sparus aurata), goldlined sea bream (Rhabdosargus sarba), goldsilk sea bream (Acanthopagrus berda), porgies, sea breams nei (Sparidae), red porgy (Pagrus pagrus), sargo breams nei (Diplodus spp.), sharpsnout sea bream (Diplodus puntazo), silver sea bream—red sea bream, snapper, pink snapper—(P. auratus), sobaity sea bream (Sparidentex hasta), white sea bream (Diplodus sargus), yellowblack sea bream (Dentex tumifrons), and yellowfin sea bream (Acanthopagrus latus).

In 2006, FAO reported aquaculture production records for 11 species with 75% of the production concentrated in just two species: the gilthead sea bream (107,620 mtn) and silver sea bream/red sea bream (75,754 mtn). The production of porgies and sea breams nei accounted for 23% (56,932 mtn) and the remaining 3847 mtn were distributed among eight other species (Table 1.2). In 1986, the Sparidae aquaculture production was 35,540 mtn, but in 2006 it reached 244,153 mtn, which represents an average annual growth rate—AGR—of 10%. However, as for many other farmed species the growth in production has seen smaller growth in value; for the same period the AGR of the value was 6% (from approximately US$358 to 1189 million), indicative of the significant reduction in price associated with the increased production. With regard to the geographical distribution of the cultured species, in 2006, almost 55% of the 244,153 mtn produced originated from the Asia-Pacific countries, consisting mainly of the red sea bream and porgies produced in Japan, China, Republic of Korea, and Taiwan Province of China (PC). A significant 44% came from gilthead sea bream production in Mediterranean countries (principally, Greece, Turkey, Spain, and Italy) and the remaining 824 mtn (0.33%) came from the Oriental Near-East countries and the Dominican Republic.

Table 1.2 The 2006 World Sparidae aquaculture production in mtn

1.3 Aquaculture status of Atlantic-Mediterranean species

1.3.1 Current status of gilthead sea bream (S. aurata) production

Scientific name: Sparus aurata (Linnaeus 1758)

FAO names: En—gilthead sea bream, Fr—Dorade royale, Es—Dorada

FishBase name: Gilthead sea bream

1.3.1.1 Main species characteristics

The gilthead sea bream (Figure 1.2) has an oval body, rather deep and compressed, with a head profile regularly curved with small eyes (FAO 2005–2009). The overall color of the body is silvery-gray; a large black blotch at the origin of the lateral line extends on the upper margin of the operculum, where it is edged below by a reddish area; a golden frontal band exists between the eyes, edged by two dark areas (not well defined in young individuals); the fork and tips of the caudal fin are edged with black. The gilthead sea bream is commonly found throughout the Mediterranean; however, it is less frequent in the eastern and south-eastern Mediterranean and very rare in the Black Sea. It is also found in the Atlantic Ocean from the British Isles to Cape Verde and around the Canary Islands (Spain). It is a benthopelagic (demersal behavior) species, found in coastal environments, inhabiting seagrass beds, rocky and sandy bottoms, as well as in the surf zone and to depths of about 30 m. Adults may be found up to 150 m deep. The species is euryhaline, often entering brackish waters. It is a sedentary fish, solitary, or forming small aggregations. It is mainly carnivorous (mollusc, particularly mussels which it can easily crush, crustaceans, and fish), but accessorily herbivorous. As regards its reproductive biology, this species is a protandrous hermaphrodite; the majority of individuals are functional males in the first two years (20–30 cm) and then turn into females (33–40 cm). Spawning typically occurs from December to April, when water temperatures are 13–17°C (Cataudella et al. 1995).

Figure 1.2 The gilthead sea bream (Sparus aurata) (FAO). (Photo courtesy of C.C. Mylonas.) (A color version of this figure appears in the color plate section)

1.3.1.2 Production cycle

Over a long time, marine fish rearing in the Mediterranean region has been exclusively based on collection of wild juveniles from the sea. Gilthead sea bream has been traditionally cultured in Italy for centuries in the northern Adriatic lagoons (known as “valli”) in extensive systems, where juveniles of this species, together with mullets (Mugilidae family), are captured in spring and stocked in the valli (Cataudella et al. 1995). At the end of the year, gilthead sea bream is stocked in overwintering ponds, to be released again in the spring in the valli. In these environments, the fish spend two or three seasons before reaching a marketable size. After the 1960s, the availability of wild juvenile decreased drastically because of overfishing and pollution, causing a difficult situation in the valli and all other rearing facilities in the north Mediterranean countries (Moretti et al. 1999). The availability of “controlled” reproduction techniques for gilthead sea bream, as well as for European seabass (Dicentrarchus labrax), generated a production scheme based on a reliable and consistent supply of juveniles, and it opened the door toward the industrialization of marine aquaculture in the Mediterranean region. The first hatcheries faced several problems with broodstock and larval culture. Good success at small-scale reproduction was first obtained in Italy, France, and Israel in 1978–1980 (Moretti et al. 1999), but large-scale production of juveniles was possible only a few years later. At present, broodstock maturation and spawning in captivity is technically feasible and does not present any constraints.

Gilthead sea bream eggs (about 0.9–1.1 mm) are produced in land-based hatcheries from selected broodstock of various age groups, from 1-year-old males to 10-year-old females. The broodstock are normally kept in tanks (10–20 m3) at a density of 4–8 kg m−1. In order to ensure a good fertilization rate, as females are batch spawners that can lay about 20,000–30,000 egg kg−3 for a period of 3–4 months, the male to female ratio is normally kept at 3:1 (Calderer & Cardona 1993). Broodstock nutrition has been proved to influence broodstock fecundity and egg/larval quality. Feeding is done on special commercial diets, as well as on squid (Fernandez-Palacios et al. 1997; Izquierdo et al. 2001). Almost all hatcheries extend the natural spawning period through the use of artificial photoperiods. A single female can produce more than 1 million eggs in a reproductive season and the normal fertilization ratio is 90–95% (Sola et al. 2007). During the first month of life, larvae may be cultured under controlled conditions in circular–conical tanks of 3–6 m diameter. Between 3 and 4 days posthatching (dph), larvae start exogenous feeding and are offered live food (rotifers Brachionus plicatilis, followed by Artemia spp.) until they complete metamorphosis. During the last 20 years, the survival rates from hatching to 2-g juvenile increased to 20%, and low cultured densities and extensive production have evolved toward shorter and more intensive production cycles (De Wolf et al. 2005). There have been significant improvements in larval nutrition, management, and hygiene. The use of commercial enrichments to improve the nutritional quality of live food (proteins, n-3 HUFA and vitamins) is a common practice in gilthead sea bream hatcheries, all this resulting in better growth and survival.

Gilthead sea bream is mainly farmed intensively in sea cages at average densities of 15–25 kg m−3 with a food conversion ratio (FCR) of 1.5–2. The culture period varies with location and water temperature, but usually it takes between 18 and 24 months for a specimen to reach 400 g from hatched larvae. Commercial size can vary from 250 g to more than 1.5 kg (APROMAR 2008). The growth of gilthead sea bream has been studied well in recent years and predictive models have been produced, using data from commercial farming in the Mediterranean Sea (Petridis & Rogdakis 1996; Mayer et al. 2008). Research in nutrition has also determined the protein and energy requirements of the species (Lupatsch et al. 2003). Commercial diets are normally extruded pellets with a 45–50% protein and about 20% lipid contents. As for most carnivorous marine fishes, the main raw materials used in feeds are fishmeal and fish oil. However, because of higher fishmeal and fish oil prices, and their increasingly limited offer, the aquafeed manufacturing companies are substituting partially these materials for alternative and sustainable vegetable sources (Sanz 2004). During the last 10 years there have also been important advances in productivity, caused by improvements in production technologies, that is, feeding systems automation, harvesting procedures, health management, etc. Selective breeding program looking at better growth rates are also carried out in gilthead sea bream since the early 2000s in France and Greece (Sola et al. 2007). The gilthead sea bream production cycle is depicted in Figure 1.3.

Figure 1.3 Schematic representation of a representative gilthead sea bream production cycle in intensive systems (from FAO).

Figure 1.4 Evolution of world capture and aquaculture production of gilthead sea bream in mtn (FAO-FishStatPlus 2008).

1.3.1.3 Gilthead sea bream current production

The total gilthead sea bream harvest in 2006 was 115,091 mtn (FAO-FishStatPlus 2008), with about 93% coming from aquaculture (Figure 1.4) and the remaining 7% (7471 mtn) coming from capture fisheries from Mediterranean countries, mainly in Egypt, Tunisia, Spain, Turkey, and France. Gilthead sea bream is traditionally cultured in Mediterranean countries in close relation with the European sea bass (Dicentrarchus labrax). Although the two species are cultured separately, their production is usually undertaken by the same companies and very frequently in the same farms. Thus, although this chapter focuses on gilthead sea bream, the reader should be aware that for a better understanding of the industry and the markets, both species are normally analyzed together (University of Stirling 2004; Monfort 2006; FAO-Globefish 2007; Luna-Sotorrío 2007).

In 2006, more than 90% of the gilthead sea bream aquaculture took place in just 5 of the 20 producing countries, with Greece being by far the leading producer (41%), followed by Turkey (26%), Spain (15%), Italy (6%), and Israel (3%). This species is currently cultured in many other Mediterranean countries, including Cyprus, France, Portugal, Croatia, Malta, Tunisia, Egypt, Albania, Bosnia and Herzegovina, Libya and Algeria, Morocco, and Slovenia. Production takes place mainly in the Mediterranean Sea, although the species is also cultured in the Atlantic Ocean (5645 mtn in 2006 from the Canary Islands, Spain) and in the Red Sea (Eilat, Israel). Production has also recently started in the Persian Gulf and the Arabian Sea (Bahrain, Kuwait, Islamic Republic of Iran, Oman, and the United Arab Emirates) (FAO/RECOFI 2009), as well as the Dominican Republic (Table 1.3).

Table 1.3 Evolution of gilthead sea bream production in tonnes

When analyzing the evolution of gilthead sea bream production, the first FAO production statistics recorded for gilthead sea bream are those from Italy in 1970 with 10 mtn. Ten years later, in 1980, eight countries reported production outputs for a total of 775 mtn. Since then production grew rapidly and in 2006 production statistics included 20 countries (Table 1.3). From 1986 to 1996 the average annual growth rate (AGR) of gilthead production peaked at 44.6%; however, during the following decade AGR was 12.5% clearly indicating a slower growth of the sector with some countries (Malta3) even undergoing a slight negative growth, while others ceased production altogether (Morocco). The main reason for the slow development of the gilthead sea bream industry at the early stages was the initial difficulty in the production of large quantities of quality juveniles. However, the development of better hatchery techniques in the 1980s, including adequate broodstock management, larval culture, and feeding, proper hygiene measures, and facility design enabled the supply of the required juveniles. Production in the 1990s was rapid, particularly in countries, such as Greece, Croatia, and Turkey, where simple and inexpensive cage structures could be used in the many protected areas along their coastline.

The great majority of juveniles required by the industry is produced on land-based hatcheries, although in some countries part of the culture still relies on the collection of wild juveniles (e.g., Egypt and Italy). Hatcheries have evolved and increased their production capacity as the demand for seed has expanded over the years. Thus, in the early days hatcheries producing yearly outputs of 1 million juveniles were considered to be large, while currently the production of 10 million or more juveniles from a single facility is the norm. At present, about 100 commercial hatcheries are in operation, with production capacities ranging from 5 million to 20 million fingerlings or more. The same countries leading the ongrowing production are also the main juvenile producers, although countries such as France, Portugal, and Cyprus have relatively larger juvenile production in relation to their ongrowing output (Table 1.4). The trend in juvenile production has followed that of growout, enabling the unit cost of juvenile production to drop considerably over the years, as a result of technological improvements (Figure 1.5). According to the Federation of European Aquaculture Producers (FEAP 2008), the unit juvenile production cost dropped considerably during the 1990s from an average of €0.48 juvenile−1 in 1990 to €0.28 juvenile−1 in 1997. In 2008, the production cost was estimated at €0.20 juvenile−1.

Table 1.4 Gilthead sea bream juvenile production by country

Source: From FEAP (2008). Note: Data from Israel not included (17 million in 2006, from Shapiro 2006).

Figure 1.5 Evolution of the gilthead sea bream juvenile production and prices (FEAP) (same countries as in Table 1.4).

1.3.1.4 Sector characteristics

The production systems for the gilthead sea bream are diverse, ranging from extensive polyculture (e.g., vallicoltura in Italy and lagoon production in Egypt) or semi-intensive production in earth ponds (Portugal and southern Spain) to highly intensive land-based systems (raceways or tanks), inshore (Greece and Turkey), and offshore sea cages (Cyprus, Italy and Spain). The farming technology applied (see Chapter 6) has evolved rapidly with the use of water recirculation technologies on land-based installations (mainly hatcheries) and the development of improved offshore cage technology (Muir & Basurco 2000; Cardia & Lovatelli 2007). At present, farming cages located in sheltered bays or semiexposed and offshore conditions are the predominant on-growing systems employed in the Mediterranean region. This technology has facilitated the rapid growth of marine aquaculture in this region. The initial small wooded cages designed for sheltered sites in inshore waters have evolved into large circular rubber cages suitable also for exposed locations, such as those in Malta, Cyprus, Sicily, the Spanish Mediterranean coast, and the Canary Islands. Although other offshore cage types (e.g., submergible or semisubmergible) have been used and tested, the main systems continue to be floating cages with a diameter ranging between 22 and 26 m.

According to a study by the University of Stirling 2004, in 2002, there were about 950 ongrowing sites operated by 700 companies, with approximately 85% of the production coming from cages (Greece, Turkey and Spain) and the remaining from land-based tanks and ponds (France, Italy, and southern Spain). Table 1.5 summarizes the key features of the gilthead sea bream and European sea bass farming industry in the main producing countries. Companies operating in the sector are very diverse in terms of size, ranging from large companies with several farms to small family enterprises. Single companies are increasingly operating one or more hatcheries and nursery facilities, and various on-growing farms. Over the last decade, the Greek aquaculture industry, for example, has experienced an important concentration process with almost half of the enterprises acquired or absorbed by larger groups. This trend is likely to continue in the near future (Barazi-Yeroulanos 2008).

Table 1.5 Key features of the gilthead sea bream and European seabass fish farming industry in the main producing countries

1.3.1.5 Production economics

Production cost varies considerably between countries and within countries, depending mainly on company characteristics (e.g., small family farms compared to large vertically integrated companies), size of operation, farming technology and the size of the final product. Some studies have also compared the production cost of different production systems, particularly land-based farms versus cage facilities (Pomelie 1995; García-García 2001; Oca et al. 2002; García-García et al. 2005). Land operations usually require higher investments, as well as more energy for pumping water, but are also more efficient in terms of FCR. The move toward cage-farming has been prompted by the lack of space along the coast and the difficulties for land-based farms to expand their production capacity and retain their competitive margins. The University of Stirling study (2004) compared the 2002 production costs for both the gilthead sea bream and the European sea bass (fish size ranging from 350 to 400 g) from different countries and showed that prices vary from €5.24 kg−1 in Portugal to €3.90 and 3.68 kg−1 in Greece and Turkey, respectively. The average production cost was around €4.24 kg−1, and predictions indicated that the costs may drop further to €3.50 kg−1. The main direct production costs include juvenile, feed, and labor that jointly account for 71% of the total cost. There are no major differences in these inputs between the main producing countries, with the exception of Turkey where labor costs are significantly lower. In Spanish offshore farming, the allocation of main production costs are 39% for feed, 21% for juveniles, and 22% for labor (Jover 2007). As it has happened in Atlantic salmon (Salmo salar) farming, the relative cost of feed increases as new technological improvements are incorporated. Already in the 1990s feed cost in Norway salmon farming was about 60% (Paquotte 1996), which indicates that there is still room for improvements in production technology and efficiency of the gilthead sea bream sector. Integrated companies, which produced their own juveniles for ongrowing, have been shown to have a financial advantage (University of Stirling 2004). Significant cost reductions have been achieved during the last years, for example, in feeding management by the incorporation of automatic and demand feeders. Further gains are likely to be realized more slowly, and probably to come from a reduction in overheads through economies of scale and the merging or association of smaller farms with larger companies, a trend that is seen in Spain and Greece. The increase of gilthead sea bream supply in the late 1990s, as it has happened in other species (e.g., trout and salmon), has caused a decrease in prices, which has forced companies to raise their production to decrease costs. In recent years, some authors have analyzed the relation between production cost and the farm production level and cage size, confirming the existence of economies of scale, where costs can be reduced and profitability increased through increases in production levels, which can be obtained by automation improvements (e.g., feeding systems), increasing stocking densities or increasing of cage number and sizes (Karagiannis & Katranidis 2000; Gasca-Leyva et al. 2003; Koçak & Tathdil 2004; García-García et al. 2005; Merinero et al. 2005; Martínez et al. 2007). Recent estimations of production cost for offshore gilthead sea bream ongrowing farms in the Spanish Mediterranean coast indicate a cost decrease from €4.34 kg−1 for a farm of 200 mtn to €3.73 kg−1 for a farm of 800 mtn (García-García et al. 2005) or a cost decrease from €3.55 kg−1 for a farm of 1000 mtn to €3.24 kg−1 for a farm producing 2500 mtn (Merinero et al. 2005). According to Jover 2007, the sector evolves toward increases in market competitiveness, for which it is necessary to look for economies of scale, the application of new technologies, and a high final product quality. Increases in farm production capacity have been seen in the sector throughout the Mediterranean region. Whereas during the 1990s, the estimated minimum production for a farm to be profitable was about 200 mtn, García-García et al. (2005) found that Spanish offshore farms in Murcia region coast could be profitable only with a production >600 mtn. Already in 2007, in Murcia, the average farm production increased to 900 mtn. Moreover, Martínez et al. (2007) estimated that for a 20% increase in profitability, a farm should produce 2000 mtn. As in other intensive aquaculture production, reduction of production cost will come through improvement in feed efficiency, juvenile quality production, health management, improved growth through selective breeding, automation, and better management.

1.3.1.6 Markets

During the late 1990s and early 2000s, the sector suffered a series of crises that caused a drop in production as a result of lower market prices. Between 1997 and 2000 the market value of the gilthead sea bream fell by about 30% from €6.01 to 4.10 kg−1. The observed price crisis resulted from an oversupply of fish brought about from uncontrolled production with poor planning, market support, and promotion (University of Stirling 2004; Rad 2007). This situation impacted seriously the profitability of many farms, causing the closure of numerous small- and middle-sized companies. There were also indications that the main markets were being saturated with regard to their current need for the traditional fresh whole fish (University of Stirling 2004; Monfort 2006). Later, however, production levels seemed to have recovered and market prices, although still variable, have stabilized somewhat. Some studies in 2007 (FAO-Globefish 2007; Luna-Sotorrío 2007) indicated that production could increase while prices would remain around €4 kg−1 but closely conditional to different consumption and general economic scenarios (FAO-Globefish 2007; Luna-Sotorrío 2007). The reader should consider that revision was written early in 2009, and that the analyzed trends on production and trade could not incorporate official statistics, showing the impacts of the international economic crisis that started in 2008. How the crisis will affect the sector is difficult to predict, and it will very much depend on its strength and duration. According to APROMAR 2009, the production of gilthead sea bream in Europe and elsewhere grew in 2008 less than in the previous years, just about 4.2%, and predictions for 2009 await for a drop in production volumes. The same study indicated a decrease on the first sale prices in 2008 of about 16.4%, reaching an average of €3.46 kg−1, the lowest ever recorded, and predicted more reductions for 2009.

Despite the general declining pattern, prices of farmed gilthead sea bream are also linked to the production seasonality. Although variations between countries exist, prices are normally higher during the summer months and lower during the fall, winter, and spring. This is due to the tendency for the industry to stock juveniles in the spring and to harvest in the autumn of the following year, resulting in large volumes of fish entering the markets at the end of summer and early fall, when the demand is declining (University of Stirling 2004). Some producers hold stocks over the winter despite the extra costs and risks involved, in order to satisfy large multiple customers who demand continuity of supply; furthermore, there is also a tendency now to grow a higher proportion of larger-sized fish to target different markets. The major markets for gilthead sea bream are located in southern European countries, where this species belongs to its fishing and consumption traditions. On the other hand, in the African countries bordering the Mediterranean Sea, this species has a small market penetration mainly due to its high price (Monfort 2006). The gilthead sea bream is normally sold as small- or medium-size whole or gutted fresh fish with markets supplied with fish of about 300–450 g. During the last decade, however, producers have increased the size of fish offered, ranging from 200 g to >1 kg. The industry is also interested in supplying fillet products; however, these are still not competitive compared with other fresh fish fillets (Luna-Sotorrío 2006). In 2007, the FEAP reported gilthead sea bream market prices ranging from €2.68 kg−1 for fish of 200–300 g to €9.61 kg−1 for fish >1 kg (Table 1.6). At present, most production (80%) comes from fish between 300 and 600 g, but producers are increasingly looking to differentiate their products, and countries, such as Italy and Spain, are now producing and placing into the market larger-sized fish.

Table 1.6 Production of gilthead sea bream by size in the main producing countries

With regard to trade, most of the production is marketed as fresh or chilled, head-on, round, or gutted fish. Greece is the main exporting country, with about two-thirds of its production exported (34,966 mtn in 2006) to various European countries (e.g., Italy, Portugal, France, Spain, Germany, and United Kingdom). The second largest exporting country is Turkey with about 10% of its production (2000 mtn in 2006) reportedly exported. The main European importing nations include Italy (13,839 mtn), Portugal (5230 mtn), France (3932 mtn), Spain (2011 mtn), Germany (1390 mtn), and the United Kingdom (1157 mtn).

1.3.2 Current status of common pandora (P. erythrinus) production

Scientific name: Pagellus erythrinus (Linnaeus 1758)

FAO names: En—Common pandora, Fr—Pageot commun, Es—Breca

FishBase name: Common pandora

1.3.2.1 Main species characteristics

This fish is characterized by a compressed oval body and rectilinear head profile (Figure 1.6), with an average length ranging from 10 to 30 cm and a maximum of 60 cm. The color is pink-red with a silvery glint. The sides are paler and the belly is whitish. There are several small bluish spots on the back and sides of the adult specimens (Vrgoč et al. 2004). The common pandora is distributed in the eastern Atlantic Ocean, from Scandinavia to Senegal, and in the entire Mediterranean Sea. It is a benthopelagic fish found in inshore waters, on various bottoms (rock, gravel, sand, and mud) commonly at depths from 20 to 100 m, and up to 200 m in the Mediterranean Sea and 300 m in the Atlantic Ocean, and move to deeper waters during winter (FishBase 2008).

Figure 1.6 The common pandora (Pagellus erythrinus) (FAO). (Photos by Gianis Issaris. Copyright Cretaquarium-Thalassocosmos archives.) (A color version of this figure appears in the color plate section)

The common pandora is a protogynous hermaphrodite, that is, matures first as female and changes to male after two years of age or when attaining a body length of 17–18 cm (Bauchot & Hureau 1990). It has been shown, however, that a small percentage of males do not develop from the opposite sex, but differentiate directly into males (Valdés et al. 2001). They reproduce from spring to autumn (Bauchot & Hureau 1986). In the Atlantic Ocean, spawning occurs in the spring, extending sometimes until early summer (Lloris et al. 1977; Cejas et al. 1993). In the Mediterranean Sea, spawning takes place from April to September (Güner et al. 2004; Klaoudatos et al. 2004; Valdés et al. 2004; Vrgoč et al. 2004). Although the common pandora is considered as an omnivorous species, it feeds mainly on benthic invertebrates and small fishes.

1.3.2.2 Production cycle

Although the life cycle of the common pandora has been closed in captivity, broodstock are collected frequently from the wild as juveniles or adults. Broodstock maturation and spawning in captivity does not present any major constraints. The spawning season of common Pandora (May to September), which does not coincide with that of the gilthead sea bream (December–April), provides the opportunity for commercial hatcheries to carry out sequential larval rearing (Klaoudatos et al. 2004). Mature broodstock have been reported to produce approximately 3.2 million eggs per kilogram, which is higher than in gilthead sea bream (Güner et al. 2004), although the eggs are smaller (700 µm). The length of the newly hatched larvae (2.03 mm) and the small size of the mouth at first opening (70–80 µm) pose some problems during initial larval feeding (Güner et al. 2004; Klaoudatos et al. 2004; Klimogianni et al. 2004).

The green-water culture technique has been employed for larval rearing and provided good larval growth at temperatures of about 19°C. Small rotifer species, such as Brachionus rotundiformis, have yielded good results during the initial larval stages (Klaoudatos et al. 2004). From 9 to 24 dph rotifers Brachionus plicatilis have been used and Artemia salina nauplii from 10 to 40 dph. The use of an inert diet starts usually 15 dph. Ongrowing has been described in sea cages with good survival rates (Klaoudatos et al. 2004; Kousoulaki et al. 2007), although somewhat lower than those for the gilthead sea bream. A marketable size of about 400 g can be achieved in 22–24 months from a juvenile weighing 2–3 g. Rearing at low densities (Klaoudatos et al. 2004) and feeding with high lipid diets have provided improved results (Kousoulaki et al. 2007).

1.3.2.3 Common pandora current production

The global Pagellus genus capture production ranged from 19,000 to 33,000 mtn between 1996 and 2006 (FAO-FishStatPlus 2008). In 2006, the common pandora accounted for about 20% of the total annual landing (4686 mtn). The capture balance comes from P. bellottii (47%), Pagellus acarne (5%), and Pagellus nei (21.1%). With the exception of Portugal, all common pandora captures came from the Mediterranean Sea with Algeria, Spain and Tunisia accounting for almost 94% of the volume landed and the balance coming from France, Cyprus, Malta, Portugal, and Slovenia.

With regard to aquaculture production, a small-scale production of this species exists in a number of farms in Greece, where production records started in 2000 with 2 mtn and reached just 197 mtn in 2006 (FAO-FishStatPlus 2008). The average price for the common pandora in the Greek market is around €7 kg−1 (Kousoulaki et al. 2007).

1.3.3 Current status of blackspot sea bream (P. bogaraveo) aquaculture production

Scientific name: Pagellus bogaraveo (Brünnich 1768)

FAO names: En—Blackspot or red sea bream, Fr—Dorade rose, Es—Besugo,

FishBase name: Blackspot sea bream

1.3.3.1 Main species characteristics

The blackspot sea bream is one of the six species of the genus Pagellus. It has an oblong reddish–grey body with a dark spot at the origin of the lateral line, and a curved upper profile of the head, with a snout shorter than the eye diameter (Figure 1.7). The regular size ranges from 15 to 50 cm with a maximum size of 70 cm. It is a benthopelagic fish, living in inshore waters above various substrates (rocks, sand, and mud) as deep as 400 m in the Mediterranean Sea and 700 m in the Atlantic Ocean (FishBase 2008). Its area of distribution includes the eastern Atlantic Ocean, where it is common in temperate waters, from Norway to Mauritania, and the western Mediterranean Sea, but less common beyond the Sicilian Strait.

Figure 1.7 The blackspot sea bream (Pagellus bogaraveo) (FAO). (Photo courtesy of M. Yufera) (A color version of this figure appears in the color plate section.)

Micale et al. (2002) suggested that blackspot sea bream is a protandrous hermaphroditic species with a high incidence of gonochoric females, which means that some females differentiate directly into females, without first maturing as males. The spawning season in the natural environment varies in terms of geographical location, that is, from August to October around the British Isles and from January to May in the Mediterranean Sea. This fish is an omnivorous species and it feeds mainly on crustaceans, molluscs, worms, and small fish (FishBase 2008).

1.3.3.2 Production cycle

Controlled broodstock maturation and spawning of the blackspot sea bream in captivity is feasible, but rather problematic because of the slow growth of the species, late maturation age, and high sensititivy to culture conditions. As a result, only one commercial operation produces this fish, in Galicia (Spain). There, spawning occurs from February to May, with a peak in March and April, at temperatures between 13 and 16°C (Peleteiro et al. 1997; JACUMAR 2003). In males, the first sexual maturity is reached at 4–5 years of age (22–25 cm) (Peleteiro et al. 2000). In Italy, according to Micale et al. 2002, spawning in captivity occurs from March to April when the male fish are around 28 cm in length and 3 years old and females around 29 cm in length and 4 years old. During spawning the ovulatory cycles occur every 48 hours. At each ovulation it has been reported that an individual weighing between 1 and 1.5 kg will release from 20 to 30 mL of eggs (Peleteiro et al. 1997), of which 40–48% are likely to hatch successfully (JACUMAR 2003).

Larval culture conditions are similar to those described for other sparids, with lower stocking densities than gilthead sea bream. Survival during larval rearing is usually around 25–30%. From 3 to 35 dph, the larvae are fed on rotifers (10 mL−1), Artemia nauplii (12 mL−1) from 30 to 35 dph and enriched Artemia of 24–48 hours (12 mL−1) from 35 to 50 dph. Weaning to an inert feed takes place at 40–50 dph, with survival rates usually between 20 and 30% (JACUMAR 2008). Preongrowing, from 2 to 40 g, generally lasts for 120 days. It is carried out in square tanks of 500 L. Mortality rate is low and usually around 5% (Olmedo et al. 1997). During ongrowing, the best results have been obtained in cages rather than on land-based tanks (Linares et al. 2001; Olmedo et al. 2002). Although there are no major problems with the ongrowing of this species, its performance is lower than that of the gilthead sea bream. In fact, it takes about 40 months for the blackspot sea bream to grow from 15 to 500 g (FCR of 2.5), while the gilthead sea bream needs 16–18 months (FCR of 1.8–2.0) to attain the same size (JACUMAR 2008).

1.3.3.3 Blackspot sea bream current production

The total world Pagellus genus capture production ranged from 19,000 to 33,000 mtn between 1996 and 2006 (FAO-FishStatPlus 2008). The main captured species is P. bellottii accounting for about 47% or 1518 mtn in 2006. In the same year, the blackspot sea bream accounted for 6.5%, while the rest came from common pandora (20%), Pagellus acarne (5%), and Pagellus nei (21%). The vast majority of blackspot sea bream captures come from the northeast Atlantic (99%), and the rest from the Mediterranean Sea and central-eastern Atlantic. Portugal (1108 mtn) and Spain (302 mtn) are the main producing countries.

With regard to aquaculture, the blackspot sea bream has only been produced in Spain. Commercial production started in 2002 with two mtn and has increased to 134 mtn in 2006, with an estimated value of US$640,000 (US$4.8 kg−1) (FAO-FishStatPlus 2008). Production in 2007, according to Spanish Ministry of Agriculture, reached 195 mtn (JACUMAR 2009). In Spain, this species is farmed in Galicia (Atlantic coast) by just one company (Isidro de la Cal) using floating net cages (Ipac.acuicultura 2005). At the wholesale market, the price of the blackspot sea bream is subject to fluctuations depending on the origin of the fish and time of the year. During the Christmas festive season the prices are highest, as this species is traditionally consumed at this time in some of the Spanish regions. In the Mercabarna4 wholesale market (Barcelona, Spain), prices show a clear difference between the capture and farmed fish, which are marketed as distinct products. Average prices in 2008 were €11.01 kg−1 for the aquaculture product and €19.29 kg−1 for the capture product. It is pointed out that normal market size in Spain for capture blackspot sea bream ranges from 1 to 3 kg whereas farmed fish are much smaller at about 500 g.

1.3.4 Current status of white sea bream (D. sargus) production

Scientific name: Diplodus sargus (Linnaeus 1758)

FAO names: En—White sea bream, Fr—Sar commun, Es—Sargo

FishBase name: White sea bream (D. sargus sargus)

1.3.4.1 Main species characteristics

The genus Diplodus is the largest within the family Sparidae, comprising 13 species and 11 subspecies (FishBase 2008). According to FishBase, D. sargus has the following six subspecies: D. sargus ascensiones (Valenciennes 1830), D. sargus cadenati (de la Paz Bauchot & Daget 1974), D. sargus helenae (Sauvage 1879), D. sargus kotschyi (Steindachner 1876), D. sargus lineatus (Valenciennes 1830), and D. sargus sargus (Linnaeus 1758).

The white sea bream (Figure 1.8) has a flat body, pressed on the sides with a forked tail. The normal size range of this species is from 15 to 30 cm, although it may reach a size of up to 45 cm. It has a light grey coloration with silver reflections and eight or nine transversal dark grey strips alternating with lighter ones that diffuse and disappear with age. The caudal fin is black-rimmed and the caudal peduncle is dark-spotted. It is a demersal fish living in brackish and marine waters on rocky or sandy bottoms as deep as 50 m. Its area of distribution comprises the Mediterranean and Black seas, and in the Atlantic Ocean from the Bay of Biscay (France/Spain) to Cape to South Africa, including the Madeira, Canaries, Cape Verde, Ascension, and St. Helena Islands (FAO Aquatic Species Fact Sheets). It is an omnivorous fish that feeds on seaweeds and benthic invertebrates, mainly small crustaceans and molluscs.

Figure 1.8 The white sea bream (Diplodus sargus) (FAO). (Photos by Gianis Issaris. Copyright Cretaquarium-Thalassocosmos archives.) (A color version of this figure appears in the color plate section.)

The white sea bream has been defined to be an “unbalanced hermaphrodite” due to the great variability of the sexual phenotype. Although most individuals can be protandrous, digyny is also probably a common reproductive style in this species, where both males and females mature from a nonfunctional intersexual phase, with some males retaining the ability of changing sex into secondary females (Micale et al. 1987; Mann & Buxton 1998; Morato et al. 2003). Sexual maturation occurs at 2 years of age and spawning occurs between March and June (Divanach et al. 1982; Micale et al. 1987; Morato et al. 2003).

1.3.4.2 Production cycle

The first attempts to culture white sea bream were carried out in the early 1980s (Divanach et al. 1982). There are also some references describing farm trials that have taken place in Greece during the 1990s (Mihelakakis & Tzoumas 19981997; Bodington 2000). Broodstock maturation and spawning in captivity does not present major constraints, and eggs can be easily obtained by spontaneous spawning (Abellán & García-Alcázar 1995), although the number of eggs produced may be lower than for the gilthead sea bream (Bodington 2000).

With regard to larval culture, good growth and survival results have been obtained under intensive farming (Abellán & García-Alcázar 1995; Bodington 2000), and more recently with the semi-intensive (mesocosmos) technique (Papandroulakis et al. 2004). Although the overall growth performance during the larval stages (60–90 days) has been better than that for sharpsnout sea bream and gilthead sea bream, the same is not true during the nursery and ongrowing phases. In fact, Abellán and García-Alcázar (1995) described white sea bream juvenile to take 4.5 months to grow from 3 to 20 g, whereas the sharpsnout and gilthead sea breams did it in 2.5 and 2 months, respectively. Low growth performance has also been observed during the ongrowing phase (Divanach et al. 1993; Abellán & García-Alcázar 1995), which made white sea bream to be considered a poor candidate for aquaculture.

However, the recent concerns from the aquaculture industry on the future availability of fishmeal and fish oil, and rising prices have renovated the interest toward omnivorous sparid species, such as the white sea bream. The poor growth performance of the species could be due to the fact that this and other species of the same genus have been fed with commercial diets optimized for the gilthead sea bream. Recent research has, in fact, worked on the nutritional requirements and fishmeal replacement for the white sea bream and results have shown that this species performs well under broad dietary protein levels, suggesting that it may have a low protein requirement and make better use of the carbohydrates (Sá et al. 2002; Ozorio et al. 2006; Sá et al. 2007; Sá et al. 2008). Furthermore, because of its omnivorous nature, good larval growth and survival, the white sea bream has been recently used in restocking experiments associated with artificial reefs, in both Italy (Gulf of Castellammare) and Portugal (Algarve coast), suggesting that this species might be adequate for restocking purposes (D’Anna et al. 2004; Santos et al. 2006).

1.3.4.3 White sea bream current production

The global Diplodus genus capture production from 1996 to 2006 averaged approximately 8600 mtn. In 2006, catches were 9309 mtn, which represented less than 1.5% of the total Sparidae capture landings (FAO-FishStatPlus 2008). The majority of catches (85%) were recorded as sargo breams nei (Diplodus spp.), followed by white sea bream with about 14.5% and South American silver porgy (Diplodus argentus) with less than 1%. Most white sea bream captures come from France, Greece, Spain, and Syria. With regard to aquaculture production, small production quantities have been reported since 1995, mainly from Greece, but also from France and Spain. Maximum production reached in 1996 with 122 mtn, and in 2006 just 38 mtn were reported to be produced in Greece.

1.3.5 Current status of sharpsnout sea bream (Diplodus puntazzo) production

Scientific name: Diplodus puntazzo (Cetti 1777)

FAO names: En—Sharpsnout sea bream, Fr—Sar à museau pointu, Es—Sargo picudo

FishBase name: Sharpsnout sea bream

1.3.5.1 Main species characteristics

Similar to the white sea bream, the sharpsnout sea bream (Figure 1.9