Construccion De Hatchery

PART 1

HATCHERY DESIGN AND CONSTRUCTION

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marine fish breeding centre is a complex facility. Because of its zootechnical characteristics, during the production season proper hatchery management requires uncommon skills and total dedication by well-trained personnel. Therefore, in designing a fish hatchery only those technical solutions that offer the best guarantees in terms ofreliability, ease of use, production capacity, hygienic working conditions and cost effectiveness have to be used. Gross mistakes in design and/or construction can risk a full production season even before it is started. In addition, temporary solutions always carry the risk of far from optimal rearing conditions, leading to disease outbreaks in fish larvae. This second part of the manual deals with theprinciples and guidelines for the design and construction of a commercial hatchery for gilthead seabream and seabass. This chapter describes how to calculate the size of the hatchery and how to select the appropriate site. It also deals with the design of production facilities. The function and the selection of hatchery systems and technical equipment are also described, focusing on the most widelyadopted technical solutions in Mediterranean hatcheries. Special attention is given to the description of the seawater intake, and to water distribution, recirculation and treatment systems, as they are among the most sensitive components of the hatchery.

Fig. 1 - A hatchery under construction

1.1

CALCULATING THE SIZE OF A HATCHERY

In order to design a marine fish hatchery, theinvestor has to have a clear idea about its production target. A decision on the size of the hatchery is a fundamental pre-requisite before starting the search for suitable sites, or before starting the technical design or the financial plan. In particular, the following issues should be addressed: • main fish species (seabass, gilthead seabream or both), • secondary species (other fish, clams, shrimps),• yearly targets as number and size of fry of each species considered,

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• origin of eggs (internal production or from other sources), • whether photoperiod and thermoperiod manipulation to shift reproductive cycles is planned, • marketing aspects (fish size and season for sales). Any aspect not properly considered during the planning phase may result in difficult workingconditions later on, requiring costly interventions to correct them (if at all possible) and causing production interruptions.

1.2 SITE SELECTION CRITERIA
The Mediterranean region is not uniform. Environmental conditions along its coastline vary considerably. Habits, customs and technical development of the countries bordering it also show large differences. The analysis of these local factors is theinitial step in the process of proper design of a hatchery. In fact, the above mentioned aspects play a crucial role in relation to the technical feasibility, but also in keeping the running costs within manageable limits. It may seem absurd, but the vast majority of Mediterranean hatchery sites were not decided on the basis of a thorough selection process, but were often already set at thebeginning of the project. This absence or scarcity of options is common both in private and public projects. In the first case, the investor usually owns the site, whereas in the public hatcheries, local and political reasons may influence the selection of a particular location regardless of technical considerations. In any case, when looking for a new site or when collecting information on apreselected location, the reconnaissance process should consider several well-defined aspects which fall under two broad categories: the natural environment and the socio-economic environment.

1.3 ENVIRONMENTAL FACTORS
A list of the main environmental parameters to be considered is given below. As a rule, historical series of data collected by national services (meteorology, oceanography, soil, etc.)...