Velvet Swords(female) Xiphophorus Helleri

Livebeared, including Guppies, Mollies, Swordtails and Platys have to be one of the most popular aquarium residents ever. Almost everybody’s first time experience with aquariums has included one or more of these beautiful and interesting fish. There are lots of different varieties with lots of different colors.

This family, Poecilliidae is commonly called the Live-bearing Toothcarp, in contrast with the Egg-laying Toothcarp, or Killifish. Live-bearing toothcarps are native to Central America, South America and North America. Livebeared appeared late in the evolutionary process - about 44-38 million years ago, during Oligoscene and Miocene periods. They have an advantage over the egglaying fish in that the young can immediately hide from predators from the moment of birth. For this reason livebearers don’t need to be as prolific as egglayers; livebearers will commonly produce only 20-40 young although a few may drop as many as 150. Like the adipose fin is a clue to a Characin, a visual clue to a livebearer is the gonopodium. Livebearers are all very hardy and are considered to be a beginners’ fish. Even so, they are a lot of fun and many experienced fish keepers continue to delight in keeping them. They generally enjoy harder water and will benefit from 1 to 1.25 teaspoons per gallon of non-iodize salt being added to the aquarium water. Indeed, the molly is often kept in saltwater aquariums and is considered to be a saltwater fish. Some also, like the platy, the short-finned molly and the swordtails are cold water fish and so can be kept without heaters.

Other Types of Aquaculture

Mollusks. Other important objects of cultivation in many parts of the world are mollusks. Though few water snails are cultivated, bivalves, especially oysters, are quite important in Asia, Europe, North America. For centuries French fishermen cultivated oysters by placing twigs in the water to which free swimming oyster larvae could attach. In northern Europe, oysters have been cultivated on the ocean bottom, but now winter temperatures limit the extent of this activity. In the Mediterranean, the Romans are said to have been the first to farm oysters. Today, oysters are cultivated on the Pacific coast of North America, as well as on the southern Atlantic coast and the Gulf of Mexico. Australia, the Philippines and South Africa also possess farms and the Japanese grow edible oysters from Hokkaido in the north to Kyushu in the south. Japanese farms are divided into two classes: some cultivate seed oysters only, while others raise them for food, especially for export. The Japanese cultivate oysters on the sea bottom (horizontally) and sticks (vertically). To collect the larvae, which affix themselves to any firm object, such as an old shell or a stone, fishermen place various devices in the water. These may be bamboo sticks with shells attached or a rope with shells hanging from it; limited tiles and wooden plates have been used for the same purpose in Europe. Production is greatest in places with good shelter against rough seas, a tidal current to carry food to the larvae, adequate salinity and optimum temperature.

After some growing time, the larvae are loosened and transported to other areas for maturation under the best conditions. While growing to marketable size, the oysters must be protected against predators, such as starfish and oyster drillers. As starfish damage cannot be completely avoided when growing oysters on the bottom, a vertical system of culture is preferred in many areas; the oysters hang in clusters or in baskets or are fixed on poles in sheltered bays. In an alternative system, the oysters remain in horizontal trays kept at some distance from the bottom. Though such tray-raised oysters are expensive, they generally survive better than those reared directly on the bottom.

Blue mussels are cultivated in Italy, Spain, France, the Netherlands and near Germany in the North Sea and the Baltic. There, too, horizontal–bottom methods have been replaced by vertical culture. Originally, the young mussels, collected from wild stocks, were spread on controlled banks leased by a fisherman from the government. Their capacity to grow in very extensive and dense beds is highly advantageous. Before full-grown mussels are sent in sacks to the market, special purification methods are employed to wash out sand. Today vertical culture is practiced with sticks pushed into the ocean bottom or with lines hanging from rafts. Unfortunately, line cultures may be damaged in winter, thus, experiments have been made with polyethylene net bags and endless tubes of polypropylene netting. These bags must be strong enough to carry the mussels until harvesting.

Many other mollusks are cultivated, including soft clams and scallops. The Japanese even raise octopuses and squid. For bivalves, the problems are roughly the same as mentioned above: collecting the larvae, raising the young mussels under good conditions, protecting them against predators, harvesting the adults without injury, sometimes cleaning for the market.

Organization of Aquaculture

In China and some countries of Europe which account for a high proportion of present day aquaculture production of the world, fish culture is done in state farms, communes or through cooperatives. In these countries, aquaculture received special attention because of the role in community welfare that aquaculture plays.

In industrially advanced countries, aquaculture is carried out by private sector, i.e. private individuals and companies. In North America, Japan and West Europe, private companies have become increasingly more prominent in the practice of aquaculture.

In developing countries, aquaculture is mostly practiced by small-scale or subsistence level farmers. In these cases, there is heavy dependence on government support, including technical and financial assistance. In most cases however, the government is not fully responsible in support of aquaculture. The reason appears to be that aquaculture lacks a firm truly fishing (capture fishery). Aquaculture does not qualify itself for governmental support and incentives given to agriculture and animal husbandry.

On the other hand, the restrictive practices intended for animal-waste disposal are at places indiscrimately applied to aquaculture, sometimes branding it as a polluter.

Most governments include aquaculture under fishery sector despite the productive phase of aquaculture being more skin to agriculture (e.g. manuring and fertilizing practices). For reasons already stated earlier, the positive role aquaculture plays in contributing to national wealth, resource utilization and production of protective protein food, aquaculture is on way to occupying a position of its own in many countries. Once the economic viability of aquaculture in respect of scores of species and multiplicity of systems is fully established everywhere, as it is bound to happen in due course of time, aquaculture will lead to “aquaplosion”.

Mariculture

Mariculture is the tem used for the cultivation of marine organisms in seawater, usually in sheltered coasted waters. In particular, the farming of marine fish is an example of mariculture and so also is the farming of marine crustaceans (such as shrimps), mollusks (such as oysters) and seaweed.

 

Integrated

Integrated Multi-Trophic Aquaculture (IMTA) is a practice in which the by-products (wastes) from one species are recycled to become input (fertilizer, food) for another. Fed aquaculture (e.g. fish, shrimp) is combined with inorganic extractive (e.g. seaweed) and organic extractive (e.g. shellfish) aquaculture to create balanced systems for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptability (better management practices).

“ Multi- Trophic” refers to the corporation of species from different trophic or nutritional levels in the same system. This is one potential distinction from the age-old practice of aquatic polyculture, which could simply be the co-culture of different fish species from the same trophic level. In this case, these organisms may all share the same biological and chemical processes, with few synergistic benefits, which could potentially lead to significant shifts in the ecosystem. Some traditional polyculture systems may, in fact, incorporate a great diversity of species, occupying several niches, as extensive cultures (low intensity, low management) within the same pond. The ”Integrated” in IMTA refers to the more intensive cultivation of the different species in approximity of each other, connected by nutrient and energy transfer through water.

Ideally, the biological and chemical processes in an IMTA system should balance. This is achieved through the appropriate selection and proportions of different species providing different ecosystem functions. The co-culture species are typically more than just biofilters; they are harvestable crops of commercial value. A working IMTA system can result in greater total production based on mutual benefits to the co-cultural species and improved ecosystem health, even if the production of individual species is lower than in a monoculture over a short term period.

Sometimes the term “Integrated Aquaculture” is used to describe the integration of monocultures through water transfer. For all intents and purposes however, the terms “ IMTA ” and “ integrated aquaculture ” differ only in their degree of descriptiveness. Aquaponics, fractionated aquaculture, IAAS (integrated agriculture-aquaculture systems), IPUAS (integrated peri-urban-aquaculture systems) and IFAS (integrated fisheries-aquaculture systems) are other variations of the IMTA concept.

 

Part 3

СИТУАТИВНІ МАТЕРІАЛИ ІЗ АКАДЕМІЧНОГО ТА ПРОФЕСІЙНОГО СЕРЕДОВИЩА СТУДЕНТІВ

Тема 1. Exercise 1. Read and translate the following text:

About Myself

First of all let me introduce myself. My first name is Victor. My second (patronymic) name is Stephanovych. My family name (surname) is Mykolayiv. I am seventeen. I was born on the 9-th of May, 1981, in Rivne. I am Ukrainian.

My family is not large. There are five of us: my father, mother, brother, sister and me. My father’s full name is Stephan Ivanovych Mykolayiv. He is 45years old. He is a doctor. He works at a hospital. My mother’s full name is Lyudmyla Volodymyrivna Mykolayeva. She is 44 years old, but she looks younger. My mother is an economist. She works at a large company. My parents like their jobs very much. They spend a lot of time at work. I would like to spend more time with them, but they are always busy. My elder brother is 6 years older than me. He is 23. He is a designer by profession. He is married. His wife is a school teacher. They have got a son. He is only 2 years old. My sister is only ten. She is a schoolgirl. My sister and I do a lot of things about the house. We clean the rooms, do shopping. It is not difficult for us. So when my parents have a little free time, we can have fun together. I think our family is friendly and united. We like to go sightseeing visiting other towns and rest in the country, where we can fish and swim in the river. Now I am a student of the 1-st course of Ecological faculty. This year I finished secondary school and entered the National University. I did well at school and I hope I will manage with my study at the University. I want to be a good student and a qualified specialist in future.

Exercise 2. Answer the following questions:

1. What is your name?

2. What is your second name?

3. How old are you?

4. Is your family large?

5. Is your brother single or married?

6. Your mother works at a large company, doesn’t she?

7. What does your sister do?

8. What University did you enter this year?

9. You are a student of Ecological faculty, aren’t you?

10. Will you be a good student or specialist?

Exercise 3. Complete the following sentences:

1. Let me ….

2. My second name is….

3. I was born ….

4. My family is ….

5. My father is ….

6. My sister is a ….

7. I am a student ….

8. We like to go ….

9. I did well ….

10. I want to be …...