Animals and Agriculture

Chapter 15Section 3

Learning Objectives

Students will be able to• Explain how overharvesting affects the supply

of aquatic organisms used for food• Describe the current role of aquaculture in

providing seafood• Describe the importance of livestock in

providing food and other products.

Things to think about and share

• What types of meat do you consume?• Can you say how the meat is produce and list

ways that the conditions in which animals are raised could affect meat quality.

• Share your understanding with your partner

Possible answers

• Crowded conditions allow diseases to spread easily

• Lack of exercise increases the fat content of meat

• Animals may be given drugs to combat disease or to grow more quickly, and these drugs may remain in the meat

The Benefits of Fish

• Rich source of proteins• It is an important source of lysine which helps

prevent hardening of the arteries and hypertension.• Polyunsaturated fats; minerals such as calcium,

phosphorus, and iron• Vitamin A, B1, B2, B12, and D and trace elements

such as iodine and zinc• Fish is beneficial to underweight preschool children

FOOD FROM WATER

• Harvesting of fish has become an important industry worldwide. When too many fish are harvested over long period of time, ecological systems can be damaged.

Overharvesting• Catching or removing from a population more organisms

than the population can replace is called overharvesting. Many governments are now trying to stop overharvesting. They have created no-fishing zones, so that fish population can recover.

Overharvesting

• Fish markets like the ones below can recover only if we have restrictions such as no-fishing zones for a few years.

AQUACULTURE

• Fish and other aquatic organisms provide up to 20 percent of the animal protein consumed worldwide. One solution to overharvesting is aquaculture, the raising of aquatic organisms for human use or consumption.

• The practice of aquaculture began in china about 4,000 years ago. Today, China leads the world in using aquaculture to produce freshwater fish.

Fish Farm• The most common method of aquaculture is a fish farm. It

generally consists of many individual ponds that each contains fish at a specific stage of development. Clean water is circulated through the ponds and brings in oxygen while sweeping away carbon dioxide and fecal wastes. The fish grow to maturity in the ponds and then are harvested.

Aquaculture: Ranch

• Another type of aquaculture is known as ranch. In this method, fish such as salmon are raised until they reach a certain age and then are released. The salmon, for example, migrate downstream to the ocean, where they live until adulthood. When they are mature, the fish return to their birthplace to reproduce. When they return, they are captured and harvested.

• Worldwide, about 23% of seafood now comes from aquaculture. Aquaculture is an important source of protein for the human diet.

Environmental damage caused by Aquaculture

• The aquatic organisms can create a large amount of waste, which can be a source of pollution.

• As aquaculture requires so much water, the process can deplete local water supplies.

• Sensitive wetlands have been damaged when large aquaculture operations were located within the wetland.

• The farming of shrimp and salmon has been found to have a negative impact on the environment. For example, when the cages are crowded, uneaten feed, fish wastes and antibiotics are released from the cages. As a source of nutrient pollution, these wastes create high levels of nutrients that increase the growth of phytoplankton and algae. The eventual degradation of algae drastically reduces the levels of oxygen in the water, which will kill fish or other organisms. Subsequently, wild fish suffer from poor water quality, the loss of bottom habitat, and the outbreaks of disease.

-• Growing a pond of salmon may require three to five pounds of wild fish. As a result, shrimp and salmon consume more protein than they produce. If the growing of fish produces a net loss of protein, then aquaculture creates a negative ecological impact.

Oyster Aquaculture

Case Study: Manhaden: The Fish Behind the Farm

• Refer to page number 396 and read the case study.• http://www.bayjournal.com/article.cfm?article=3857• Link to know more about overfishing• http://www.savingseafood.org/state-local/maryland-bill-targets-me

nhaden-reduction-industry-2.htmlMaryland Bill Targets Menhaden Reduction Industry• What changes would you suggest to prevent the fishery from

declining?• Research the current status of Menhaden and the Chesapeake Bay

ecosystem.• Menhaden is considered to be a keystone species. Find out what is

a keystone species and list and explain any three keystone species with pictures

http://www.carrollcountytimes.com/columnists/sports/bill_may/case-for-menhaden-conservation/article_096ea7e8-dbcb-11e0-921c-001cc4c002e0.htmlCase for menhaden conservation

Livestock

• Domesticated animals that are raised to be used on a farm or ranch or to be sold for profit are called livestock. Livestock operations, such as the pig farms, produce most of the meat that is consumed in developed countries.

-

• Livestock are also important in developing countries. In these countries, livestock not only provide leather, wool, eggs, and meat, but also serve many other functions. Some livestock are used as draft animals to pull carts and plows. Other livestock provide manure as the main source of plant fertilizer or as a fuel for cooking.

Ruminants • Cattle, sheep, and goats are ruminants. Ruminants have

microorganism in their intestines that allow the animals to digest plant materials that humans cannot digest. When we eat the meat of ruminants, we are using them to convert plant material, such as grass stems and woody shrubs, into food that we can digest – such as beef.

• Cattle are not always slaughtered for meat. In Africa for example, traditional Masai herders drink milk and blood from their cattle, but the herds rarely kill them for meat.

• In India, cattle are not killed or eaten because cows are sacred to Hindus, who make up a large part of India’s population. These cattle instead produce milk and dung, and the cattle are used as draft animals.

Poultry

• Chickens are a type of poultry, domesticated birds raised for meat and eggs, which are good sources of essential amino acids. In more-developed countries, chickens and turkeys are usually raised in factory farms.

Poultry: Ducks• Fewer ducks and geese are raised worldwide than

chickens, but in some areas ducks and geese are economically important. The duck’s droppings are used to fertilize fields of rice called rice paddies. The rice paddies are flooded several times per year with water from nearby ponds. Mulberry trees are also irrigated by the ponds. Plant materials and filtered sewage are dumped in the ponds and serve as food for carp and other fish. The integrated system uses little fresh water, recycles waste, and produces ducks, silk, rice, and fish.

•

Brain Food

Controlling Disease the Organic wayIn organic livestock farming, farmers avoid

using synthetic medications and hormones. Diseases and parasites are avoided through preventative measures such as rotational grazing, carefully balanced diets, sanitary conditions, and gentle treatment of the animals.

Environmental impacts associated with producing meat

• http://allgreen.com/site/index.php?option=com_content&task=view&id=300&Itemid=1

• http://www.peta.org/issues/animals-used-for-food/meat-and-environment.aspx

• Make use of the above links and also you can use other sources to find out the environmental impacts associated with meat production