Hatchery culture of bivalves

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A practical manual

Prepared by Michael M. Helm

FAO Consultant Nova Scotia, Canada

and

Neil Bourne FAO Consultant British Columbia, Canada

Compiled and edited by Alessandro Lovatelli

Inland Water Resources and Aquaculture Department FAO Fisheries DepartmentRome, Italy

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS

Rome, 2004

Cover photographs:

Clockwise from top left: Fibrebreglass cylinders used for of a small bivalve hatchery; photomicrograph raft nursery Crassostrea D-larvae (courtesy Michael M.gigas Manila clam (courtesy Brian Edwards).

The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

ISBN 92-5-105224-7ISSN 0429-9345

Bivalve mollusc culture is an important and rapidly expanding area of world aquaculture production, representing approximately 20 percent of the sector’s output at 14 million tonnes in 2000. The majority of production is from natural populations although increasingly stocks are approaching or have exceeded maximum sustainable yields. Stock enhancement through the capture and relaying of natural seed in both extensive and intensive forms of culture is common practice worldwide but the reliability of natural recruitment can never be guaranteed, and conflicts over the use of the coastal zone are becoming ever more pressing. A solution to meeting the seed requirements of the bivalve industry, applicable to the production of high unit value species such as clams, oysters and scallops, is hatchery culture. The production of seed through hatchery propagation accounts at the present time for only a small percentage of the total seed requirement but it is likely to become increasingly important as work continues to produce genetically- selected strains with desirable characteristics suited to particular conditions.

The advent of bivalve hatcheries was in Europe and the United States in the 1960s. Since those early pioneering days, knowledge of the biological requirements of the various species that predominate in worldwide aquaculture production and the technology used to produce them has grown and continues to improve. This manual brings together the current state of knowledge in describing the various aspects of hatchery culture and production from acquisition of broodstock to the stage at which the seed are of sufficient size to transfer to sea-based growout. Focus is on intensive methodology in purpose- built hatchery facilities rather than on more extensive methods of seed production in land-based pond systems. For a complete view, the intermediate nursery phase of production, which is the interface between the hatchery and sea-based growout, and the concept of remote setting are also described and discussed in some depth.

This manual is not intended as a scientific treatise on the subject. Rather, it provides the reader with a practical insight as to what is required in the way of resources and details of how to handle and manage the various life history stages of bivalves in the hatchery production cycle. Examples are largely drawn from the more commonly cultured temperate climate species including the Pacific oyster, Crassostrea gigas, the American (Eastern) oyster, Crassostrea virginica, the European flat oyster, Ostrea edulis, the Manila clam, Tapes philippinarum and a range of scallop species. Consideration is also given to the culture of tropical bivalves. Methods described are equally as applicable to bivalves of lesser significance in terms of worldwide production.

The authors recognize that bivalve hatchery production is as much an art founded on science as it is a science per se. There are as many ways of operating and managing a hatchery as there are hatcheries in terms of the sophistication of the facility and the precision with which each part of production is approached. In this respect, many experienced hatchery managers will consider much of the detailed information as "overkill." However, the authors have considered the need for a thorough grounding for new entrants in this field, not just how the various procedures are done but the biological basis of why they are done in that way. Thus, the content is equally as appropriate to the operation of a closely controlled experimental hatchery as it is to a commercial-scale hatchery.

In addition to explanations of culture technology and methodology, the manual includes a brief discussion of the processes of identifying a suitable site for locating a hatchery and considerations in planning and designing the hatchery. It also includes advances that are likely to improve the reliability and economic viability of the hatchery industry in the near future, featuring topics such as polyploidy, the development of selected strains, cryopreservation of gametes and the need for novel, non-living foods.

Keywords: marine aquaculture, bivalve culture, bivalve hatcheries, bivalve nurseries, bivalve seed production, oysters, clams, scallops

Helm, M.M.; Bourne, N.; Lovatelli, A. (comp./ed.)Hatchery culture of bivalves. A practical manual.FAO Fisheries Technical Paper. No. 471. Rome, FAO. 2004. 177p.

All rights reserved. Reproduction and dissemination of material in this information product for educational or other non-commercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged. Reproduction of material in this information product for resale or other commercial purposes is prohibited without written permission of the copyright holders.Applications for such permission should be addressed to:ChiefPublishing Management ServiceInformation DivisionFAOViale delle Terme di Caracalla, 00100 Rome, Italyor by e-mail to:copyright@fao.org

© FAO 2004

Contents

1.1.1 Introduction1.1.2 Considerations1.1.2.1 Government regulations1.1.2.2 Seawater quality1.1.2.3 Siting the hatchery
1.2.1 Introduction1.2.2 Seawater system1.2.3 The physical plant1.2.3.1 Algal culture facility1.2.3.2 Broodstock holding and spawning area1.2.3.3 Larval culture area1.2.3.4 Juvenile culture area1.2.3.5 Other space requirements
2.1.1 Introduction2.1.2 External anatomy2.1.3 Internal anatomy
2.2.1 Gonadal development and spawning2.2.2 Embryonic and larval development2.2.3 Metamorphosis2.2.4 Feeding2.2.5 Growth2.2.6 Mortalities
3.2.1 Procedures for the management of stock cultures3.2.2 Starter culture manageme
3.3.1 Growth phases of cultures3.3.2 Details of intermediate-scale culture operation3.3.3 Estimating algal density
3.4.1 Bag and cylinder cultures3.4.2 Internally illuminated cultures3.4.3 Principles of large-scale culture management3.4.4 Automated large-scale culture3.4.5 Troubleshooting3.4.6 Extensive outdoor culture
4.1.1 Introduction4.1.2 Conditioning methods4.1.2.1 Tank systems and water treatment4.1.2.2 Feeding broodstock4.1.2.3 Calculating food ration for conditioning4.1.2.4 Adjusting ration for flow-through systems4.1.2.5 Two-stage early season conditioning4.1.3 Conditioning bivalves in the tropics
4.2.1 Introduction4.2.2 Gamete stripping4.2.3 The special case of flat oysters4.2.4 Induced spawning of oviparous bivalves4.2.4.1 Thermal cycling procedure4.2.4.2 Spawning dioecious bivalves4.2.4.3 Spawning monoecious bivalves4.2.5 Fertilization procedures
5.1.1 Introduction5.1.2 Methods for embryo development5.1.2.1 Tanks for embryos and larvae5.1.2.2 Water treatment5.1.2.3 Culture of embryos5.1.3 Methods for rearing larvae5.1.3.1 Starting a new culture5.1.3.2 Husbandry of larval cultures5.1.4 Growing larvae more efficiently5.1.4.1 High density culture5.1.4.2 Flow-through culture5.1.5 Growth and survival of larvae
5.2.1 Introduction5.2.2 Dietary considerations5.2.3 Diet composition and ration5.2.3.1 Feeding strategies5.2.3.2 Calculating food rations
5.3.1 Introduction5.3.2 Effects of temperature and salinity5.3.3 Seawater quality5.3.4 Egg and larval quality5.3.5 Disease
5.4.1 Introduction5.4.2 Maturation of larvae5.4.3 Setting larvae5.4.3.1 Settlement stimuli5.4.3.2 Suitable settlement substrates
6.2.1 Background6.2.2 Preparing larvae for shipment6.2.3 Preparations at the remote site6.2.4 Receiving the eyed larvae6.2.5 Setting the larvae and growing the spat
6.3.1 Introduction6.3.2 Growing systems for spat set on cultch6.3.3 Growing systems for unattached spat6.3.4 Operation of closed upwelling systems6.3.5 Operation of closed downwelling systems6.3.6 Grading and estimating spat6.3.7 Operating systems on flow-through
6.4.1 Species composition of diets6.4.2 Calculating food ration
6.5.1 Variability in spat growth between species6.5.2 Effect of ration on growth6.5.3 Combined effects of ration and temperature6.5.4 Survival6.5.5 Hatchery production
6.6.1 Land-based nurseries6.6.2 Barge-type nurseries
7.1.1 Polyploidy7.1.2 Quantitative and molecular genetics