Respuesta :
Answer:
C
Explanation:
Pls mark brainliest if correct
Hoope it helpsss
Answer:
Sustainable fishing guarantees there will be populations of ocean and freshwater wildlife for the future. Aquatic environments are home to countless species of fish and invertebrates, most of which are consumed as food. (Others are harvested for economic reasons, such as oysters that produce pearls used in jewelry.) Seafood is respected all over the world, in many diverse cultures, as an important source of protein and healthy fats. For thousands of years, people have fished to feed families and local communities.
Demand for seafood and advances in technology have led to fishing practices that are depleting fish and shellfish populations around the world. Fishers remove more than 77 billion kilograms (170 billion pounds) of wildlife from the sea each year. Scientists fear that continuing to fish at this rate may soon result in a collapse of the world’s fisheries. In order to continue relying on the ocean as an important food source, economists and conservationists say we will need to employ sustainable fishing practices.
Consider the example of the bluefin tuna. This fish is one of the largest and fastest on Earth. It is known for its delicious meat, which is often enjoyed raw, as sushi. Demand for this particular fish has resulted in very high prices at markets and has threatened its population. Today’s spawning population of bluefin tuna is estimated at 21 to 29 percent of its population in 1970.
Since about that time, commercial fishers have caught bluefin tuna using purse seining and longlining. Purse seine fishing uses a net to herd fish together and then envelop them by pulling the net’s drawstring. The net can scoop up many fish at a time, and is typically used to catch schooling fish or those that come together to spawn. Longlining is a type of fishing in which a very long line—up to 100 kilometers (62 miles)—is set and dragged behind a boat. These lines have thousands of baited hooks attached to smaller lines stretching downward.
Both purse seining and longlining are efficient fishing methods. These techniques can catch hundreds or thousands of fish at a time.
Overfishing
Catching so many fish at a time can result in an immediate payoff for fishers. Fishing this way consistently, however, leaves few fish of a species left in the ocean. If a fish population is small, it cannot easily replenish itself through reproduction.
Taking wildlife from the sea faster than populations can reproduce is known as overfishing. Purse seining, longlining, and many other types of fishing can also result in a lot of bycatch, the capture of unintended species. Longlines intended to catch bluefin tuna (Thunnus thynnus), for instance, can ensnare birds, sea turtles, and other fish such as swordfish (Xiphias gladius).
Another fish species that has been overfished is Chilean seabass (Dissostichus eleginoides), sometimes called Patagonian toothfish. In the 1990s, this fish became extremely popular in restaurants across the United States and other countries, causing an increase in demand. The fish is native to the South Pacific and South Atlantic Oceans, typically caught by longline in international waters. Fishing in this area is regulated by international agreements, which are very difficult to enforce. Illegal fishing—in this case catching fish in numbers high above internationally established limits—became widespread. The number of fish caught and the average size of the fish decreased, leading to even higher prices and greater incentive for illegal fishing. Chilean seabass is a long-lived (up to 50 years), slow-growing fish. Smaller seabass are likely younger, and may not have spawned yet. As fishers caught smaller seabass, healthy replenishment of the population became unlikely.
By the early 2000s, hundreds of American chefs joined a campaign to “Take a Pass on Chilean Sea Bass,” with the hope of giving the fishery time to recover. Today, import of Chilean seabass into the United States is highly regulated by the National Marine Fisheries Service, but illegal fishing continues.
Overfishing also occurs in freshwater ecosystems. The Caspian Sea, for instance, is home to the beluga sturgeon (Huso huso), a large, slow-growing fish. Beluga sturgeon can grow up to 4.5 meters (15 feet) and 1,135 kilograms (2,500 pounds). They take about 20 years to reach maturity, at which point females release their eggs (called roe), although they only do so every three to four years. Beluga sturgeon are best known for roe—also known as caviar. In fact, Caspian Sea sturgeon are the source of about 90 percent of the world’s caviar. The fish are slow-moving and easy prey for fishers. When its eggs are harvested, the fish cannot maintain their populations.
