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Aquaculture microbiology (I)

Topic 9Ms Sherina

Kamal

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Introduction

Aquaculture also known as fish or shellfish ……………..refers to the breeding, rearing, and

harvesting of plants and animals in all types of water environments including ponds, rivers, lakes, and ……………….

Researchers and aquaculture producers are "farming" all kinds of freshwater and marine species of fish, shellfish, and ……………….

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IntroductionAquaculture produces:

• food fish• sport fish• bait fish• ornamental fish• Crustaceans• Mollusks• Algae• Sea vegetables• fish eggs

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Introduction

the production of seafood from hatchery fish and shellfish which are grown to market size in ponds, tanks, cages, or raceways

Stock restoration or "enhancement" is a form of aquaculture in which hatchery fish and shellfish are released into the wild to rebuild wild populations or coastal habitats oyster reefs

Introduction includes the production of

ornamental fish for the aquarium tradegrowing plant species used in a range of

• …………• pharmaceutical• nutritional• biotechnology products

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Introduction

Two types of aquaculture:Marine……………

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Introduction

Marine aquaculture refers to the culturing of species that live in the ocean U.S. marine aquaculture primarily produces:

• Oysters• …………..• mussels• …………..• salmon• Cod• ……………• Barramundi• Seabass• Seabream

Introduction

Marine aquaculture can take place:• in the ocean (cages, on the seafloor, or

suspended in the water column) • in on-land, manmade systems

• ponds or tanks• Recirculating aquaculture systems that

reduce, reuse, and recycle water and waste can support some marine species

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Introduction

Freshwater aquacultureproduces species that are native to

rivers, lakes and …………..dominated by catfish but also

produces trout, tilapia, and …………..takes place primarily in ponds and in

on-land, manmade systems

• Re-circulating aquaculture systems

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Aquaculture techniques have developed or adapted many specific techniques to improve their

operations some drawn readily from other fields some which have had to be devised by farmers and technicians They range from simple field tricks like moistening soil and rolling it into

an elongated shape to test whether there is enough clay in the soil to make watertight pond dykes

through to advanced biotechnology • gene transfer

As the sector has expanded to new regions, new species and to achieve control over more of the life cycle of farmed animals and plants, fish farmers have proven very innovative in devising solutions to the new problems they faced

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Aquaculture techniques

The culture of carp was originally restricted to the home range of each species, where fry (seed) could be caught from the rivers and stocked in ponds

A study of how water temperatures, changes in day length and other factors affected the reproductive cycle of fish subsequently led to the ability to breed carp far from their native waters and where the natural conditions would not normally allow breeding

Manipulation of water temperatures and day length remains important in the successful hatchery production of many farmed species to this day

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Aquaculture techniques

As ……………….. became identified and their action understood in higher vertebrates, fish farmers began to experiment too, with extracts of hormone producing organs in fish, and found that egg development and spawning could be promoted in many species by the injection of hormone extracts from pituitary gland

These techniques are used today in the production of fish Carp Salmon ………….

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Aquaculture techniques

Oysters and other mollusks are brought to produce eggs by manipulating water temperatures

Shrimp made to develop their ovaries by removing a gland that

produces an inhibitory hormone, sited in the eyestalk Tilapia

Hormones are also used in processes like the sex-reversal of tilapia to produce all-male populations …………………………. production

There is a short period in the early life of the fish when their sex is not fully determined and feeding them with a hormone treated feed can push them to …………………………………..

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Aquaculture techniques

Many fish are stripped of their eggs (females) and milt (males) in hatchery production and the fertilisation is carried out externally

Typically this is done in a bowl with the eggs and sperm being mixed with a feather

Shrimp that do not readily mate in captivity are artificially inseminated by extracting the sperm capsule from the male and attaching it to a female that has ripe ovaries to replicate ………………………………….

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Aquaculture Methods

Open-net pen systems Closed Systems

RacewaysRecirculation systems……………Suspended-aquaculture

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Open-net pen systems

Found offshore in coastal areas or in freshwater lakes, open-net pens or ‘cages’ considered a high-risk aquaculture method

• they allow for free and unregulated exchange between the farm and the surrounding environment

Farmed …………….. Open net pens allow free exchange of high concentrations

of waste, chemicals, parasites and disease Farmed fish can escape and they also attract predators:

marine mammals, that can get tangled and drown in fish farm …………..17

Closed Systems

use a barrier to control the exchange between farms and the natural environment

Significantly: reduces pollution ………………………. negative wildlife interactions and parasite disease transfer from farms to marine and freshwater

ecosystems

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Closed Systems: Raceways

Flowing water is diverted from natural streams or a well used for raising rainbow trout To be considered a low-risk method

waste must be treated and fish ……………………….

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Closed Systems:Recirculation systems

Water in these systems is treated and re-circulated almost any type of finfish can be raised Common species farmed:

Arctic char striped bass Barramundi Sturgeon Salmon

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Closed Systems:Recirculation systems

This system does not mix with natural water sources• mitigates pollution• parasite transfer • fish escapes

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Closed Systems: Ponds Ponds are semi- or fully enclosed body ……………….. Catfish, tilapia and shrimp Discharged waste must be

filtered and treated to be considered a “low-risk” method “High-risk” pond farms discharge untreated wastewater

which pollutes the surrounding environment They can also cause devastating habitat destruction For example, the construction of shrimp ponds in Asia

and South America  has destroyed 3.7 million acres of mangrove forests along the coast

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Closed Systems: Suspended-aquaculture

Farmers grow shellfish on beaches or suspend them in water by Ropes plastic trays …………………

The shellfish farmed using these methods are filter feeders and require only clean water to thrive

Oysters, mussels and ………………… Shellfish farming with suspended-aquaculture  is

often ‘low risk’ if the farmed species is native to the area and if the farm has sufficient flow to prevent waste accumulation

Closed Systems: Suspended-aquaculture

END OF LECTURE

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