19.1.1 Learning Objectives

The learning objectives of this unit are as follows:
1. to be able to describe what is Aquaculture;
2. to be able to describe the factors affecting Aquaculture production in general and
3. to be able to describe the features of an Aquaculture production system.

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19.1.2 Fish & Aquaculture

 

The “Factors affecting Animal Production” have been enumerated in Module 14. What makes Aquaculture production interesting and challenging is that the housing and environment is simply the water in which the aquatic animal lives. In this environment are mixed Oxygen, Carbon Dioxide, Feed and Nutrients, Digestive Wastes and Water.

 

This is a very dynamic and complex fluid medium which has to be managed or the desirable fish will all die. [Please refer to the Problem on: Floating Tilapia]. Recent research has shown the advantages of fish farming as an alternative type of livestock production.    

               

Aquaculture - the science of fish and water life creatures (animals) farming or production to meet human needs for food and pleasure; this dates back to 4000 years ago in China, Japan and Egypt, 3000 years ago in India and Java and 2500 years ago in Europe. It can be classified as follows:
           
1. Freshwater Production
 (i) Tropical Warm water culture (70^o to 100^oF): (21^o to 38^oC)
e.g. Catfish (USA)

• Tilapia Tilapia nilotica ( Silver and Red Tilapia)
• Tilapia mossambica (Black Tilapia)
• Oreochromis niloticus (Nile Tilapia)
• Cascadura Hoplosternum littorale (Caribbean)
• and Malaysian Prawns Macrobrachium rosenbergii

(ii) Cold water culture (40^o to 60^oF): (4^oto 16^oC)
e.g. Trout and Salmon

 

2. Marine Water Production [Saline or Salt Water Systems]
e.g. Oyster and Clams

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19.1.3 Basic Production Systems

 

Within these two types of production systems - four systems of Aquaculture Production Management can be listed.

 

(i) Hatchery Operation:
Young aquatic species are hatched and raised to a size where they can be released into natural populations to grow and reproduce.

 

(ii) Capture of Young Aquatic Species:
Young aquatic species are captured and grown to market weight on supplemental feeding or on natural feeds in the environment aided by active fertilization of the water.

 

(iii) Growing of Young Aquatic Species to market weight:
In this system the farmer is only concerned with growing fish and does not attempt to select breeding stock. Shrimp farming is an example of this system.

 

(iv) Management of an Entire Life Cycle:
Catfish and Trout Production in the USA, and Tilapia Farming in the Caribbean (Jamaica, Dominica and Trinidad) are examples of this. Young fish are hatched and grown, either to be marketed or kept as replacement breeder stock.

At the Sugarcane Feeds Center and the Institute of Marine Affairs, this is done.

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19.1.4 The Basic Components of an Aquaculture Production System

 

In approaching the production of any aquatic species we first need to address the unique needs of these animals in contrast to terrestrial animals. These would now be itemized for you below.

 

1] Water Supply and a Reliable Source of Water are essential.

- Water pumps or a gravity feeding system for supplying the water are at the center of this.

 

2] A Drainage System and a procedure and system for water level management is the most important pond management activity.

 

3] The Ponds are the shell of the housing system for fish with the water being the core. The concept of the ponds could be anything used to hold and manage the water in which the animals live any part of their life cycle. The ponds would could be :
- Reproduction ponds or tanks
- Hatchery tanks
- Tanks for Juvenile Stages
- Grow out tanks or ponds.

 

4] The Aeration System is the means by which the water in which the aquatic animals live are kept supplied with suitable levels of oxygen. This could consist of any of the following:
- air pumps
- wind paddles
- water pumps
- animals (wading ducks) or
- the prevailing wind system.

 

5] Aquatic Species for Production: This is self-explanatory.

 

6] The Harvesting and Animal Handling System consists of the methods used at catching, sorting, making observations and any other activities involved in managing the animals. Nets of various mesh sizes are used for different physiological states.

 

7] The Feeding System involves the diets, the nutritional program, the rations and the system of feed delivery.

 

8] The Breeding and Animal Management Program includes life cycle management, sexual differentiation in ponds and the control of reproduction in the grow out ponds.

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19.1.5 Some Basic Considerations for an Aquaculture Production System

 

19.1.5.1 Location
Is water available easily and year round?
What is the “Water Quality” like?
Is there the potential for “Predation” by birds, man, alligators etc. ?
What is the soil topography like? Is it flat and is it accessible?
Is there electricity?

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19.1.5.2 Soil Factors
What is the Soil Type, pH, Nutrient Status, OM content and Water Holding Capacity?
The soil should have about 30-50% Clay at a depth of 3 feet to promote water retention within the ponds.

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19.1.5.3 Pond Construction and Design

Orientation of Pond with regard to prevailing winds is important.
The other considerations for the pond are:
-Length of Pond
-Width of Pond
-Depth of Pond
-Pond Drainage Considerations
-Aeration of Pond.

 

Readings:
Please refer to Ramnarine (1989) for further information on Pond Construction and Design.

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19.1.5.4 The Species and the Type of Production System

The specific requirements of the Species Production Model in question will be based on its life cycle. This would determine the following:
- Pond Use and Objectives;
- The method of production to be employed;
- Methods of Harvesting and
- Marketing System to be employed.

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19.1.5.5 The Harvesting and Marketing System
The features of the life cycle will dictate in what form and to which of the following the animal output will be sold-

• to consumers
• to wholesalers
• to processors.

In selling to processors you must have an appreciation of what percentage of total product volume, weight or quantity is considered waste.

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19.1.6 The Role of Fish in our Lives

Fish contributes only a small percentage of our diets in most parts of the world, yet after air, water is the most abundant element surrounding us.
Fish are cold blooded animals i.e. their body temperature adjusts to that of the environment. Thus from a production stand point this affords certain advantages and disadvantages when comparing fish farming with the production of conventional warm-blooded livestock species.

Advantage:
i) As the fish adjusts its body temperature to that of the environment, there is a reduction in the amount of energy required for maintenance.

Disadvantage:
(i) Fish are very susceptible to stresses which result from changes in the environment pH, [N] in the form of ammonia or nitrates, salinity, content of toxic run-off. The fish’s' immediate environment is the water.

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19.1.7 Feeding of Fish

Within the classification of vertebrates there are more species of fish than any other animal. Fish species number between 15000 to 17000; Avian species roughly number 8600, and mammalian species, 4500. Among this vast species of fish there is represented almost all types of feeding behavior.

Fish can be classified in three types of eaters:

(i) Carnivores: Consume primarily animal material.
Food consumed by these fish can be as small as a microscopic crustacean or insect to as large as an amphibian or a small mammal.

(ii) Herbivore: Subsist primarily on the available vegetation and decayed organic material in the environment.

(iii) Omnivores: Consume almost any food source of either plant or animal origin.

 

Anatomical changes in the mouth of fish in response to adaptation to feeding habits
Due to the well-defined differences in the organization and structure of the mouth it is possible to classify fish according to their feeding habits into the following categories:

1. Predators
2. Grazers
3. Strainers
4. Suckers
5. Parasites

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19.1.8 Recommended Readings

 

Arrignon, J. C. V.; Huner, J. V. ; Laurent, P. J. ; Gressinger, J. M. ; Lacroix, D.; Gondouin, P. and Autrand, M.(1994): Warm-water crustaceans. The Tropical Agriculturalist: Series Editor Rene Coste, CTA, MACMILLAN, London and Basingstoke, 160 pages.

 

Ramnarine, I. (1989): Cascadura farming, a manual for the culture of Hoplosternum littorale. Occasional Paper #7, Department of Zoology, The University of the West Indies, St Augustine, Trinidad. 34pp.

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