8.4 Give English equivalents:

Естественная среда, период роста, садок, сетевой садок, инкубатор, ступенчатые уклоны, открытое море.

8.5 Match the words with their definitions.

1) pond acreage	a) An aquaculture system that consists of mesh enclosures (or sometimes cages), typically placed in coastal areas. There is no effective barrier between the netpen interior and the ocean. Wastes are emitted directly into the surrounding waters.
2) fish nursery	b) One of the earliest types of aquaculture to be practiced. They can either be natural or artificially constructed. They are usually shallow, with sides that are not too steep in order to prevent erosion.
3) net-pen system	c) area committed to extensive aquaculture holdings at a fish farm or company.
4) pond system	d The outlet structures from an aquaculture pond or tank, including monk regulator, drain pipe and drain canal, allowing discharge or re-circulation, as required.
5) pond drainage system	e) The first production stage in fish farming, nursing fry (about 1.0 gram) to fingerling (60-100 gram).

8.6 Fill in the gaps using the words given below:

Pond ecology. The biological interactions occurring between different organism … developing within the aquaculture …, either intentional stocked populations and inadvertently inoculated. In open aquaculture …, this usually includes water …: algae primary producers, secondary producers and bottom populations which include … populations and higher organisms.

Bacterial, systems, ponds, populations, organisms, zooplankton.

8.7 Answer the questions

1) What is typical pond?

2) What should a well designed pond have?

3) What are raceways?

4) What are raceways used for?

5) Is die water exchanged in raceways or not?

6) What is the difference between cages and net-pens?

8.8 Read the text without a dictionary. Types of aquaculture opeations

Aquaculture operations range from small, backyard water gardens to energy-intensive, large commercial farms encompassing hundreds of hectares . Aquaculture is sometimes combined with agriculture as in rice–fish farming, or in duck–fish ponds. It is also practiced as polyculture, where a variety of species occupying different ecological niches are cultivated together. Aquaculture involves many levels of intensity and complexity, from gravity-fed ponds with little or no inputs, to intensive systems that use aeration , supplemental feeds, antibiotics, and genetically modified species.

Systems for rearing fish depend on the environment and the objective of the aquaculture operation. In the United States and worldwide, the most common rearing unit is the pond, although other types of units are also used: cages,net pens , flow-through raceways, and recirculation tanks. Efficient farm management and careful water-quality management are keys to a successful operation, regardless of the culture unit. With poor water quality, for example, fish exhibit higher incidence of disease. In addition, poor water quality often yields effluents (wastewater and byproducts) that can have negative environmental effects.

Small skiffs shuttle 80-meter-circumference salmon rearing pens around the harbor at a commercial fish farm in Dover, Tasmania, Australia. Pens must be moved periodically to reduce negative impacts of fish waste on substrate environments below the pens.