水产养殖专业英语

水产养殖专业英语

Ocean Today

一

Open Rivers, Abundant Fish

Many species of fish, including those that are important to the U.S. economy, migrate from the ocean to freshwater rivers and streams to spawn. After spending years in the ocean, fish instinctually return to the same rivers where they were born, making the often-treacherous journey upstream. Some fish, like salmon, travel nearly a thousand miles.

If they make it past strong river currents and hungry predators, these determined fish may then find themselves blocked by man-made barriers, such as dams.

As many as two million dams and culverts are located in the streams and rivers of the United States.Unfortunately, many of them block access to more than 600,000 miles of river habitat.Special “fish ladders”are built to help fish pass over these dams so they can continue swimming upstream to reach their spawning grounds.

Some of the dams that block fish passage are important producers of clean electrical power. But other dams in the way of fish migrations are old and out of use, even dangerous if they are left unchecked and not maintained. Often the best solution is to take them down.

In 2007, Portland General Electric removed the Marmot Dam in Oregon, which opened 100 miles of freshwater habitat to thousands of migrating fish. Among them were several salmon species, which are listed as 'threatened' under the Endangered Species Act.

The Merrimack Village Dam in New Hampshire was another successful dam removal. The small dam, originally built in the 1730s, had fallen into disuse and disrepair.

Loiselle:

“Removal of the Merrimack Village Dam is going to make way for river herring, American shad, American eels, and Atlantic salmon that have been blocked from migrating up the Souhegan River for almost two and a half centuries.

…[big smile] we anticipate that we’re going to see many more fish, other wildlife in the area and in our river system than we’ve ever seen before.”

NARRATOR:

When we remove a barrier to migrating fish, we not only increase the health and quantity of local fish populations, we also increase the overall health of the river and even the economic health of the community.

NOAA has helped remove over 50 dams in 12 years, enabling migratory fish to finally reach their historic habitat.

二

Fish on a Farm

Every weekend small farmers around the country head to their local farmer’s markets to sell

their fruits and veggies.

Well guess what? There’s a new farmer in town. Fish farmers.

In the U.S., we import over 80% of the seafood we eat, and half of that is farmed. This growing demand for safe, healthy seafood has prompted a revival of the fish farming industry here at

home.

Farmers raise finfish using a variety of methods, but they all start out with baby fish or fingerlings raised in a hatchery. Once they are large enough, the fish are placed in either surface pens near the shore or submersible cages in the open ocean. The netting or cages allow ocean water to flow in and out, but keeps the fish contained in one area.Fish food is dispensed from buoys floating on the surface at the top of the pen. Once the fish have matured –they are harvested using large vacuums. The fish are then prepped, placed on ice, and taken to market. There are some environmental concerns associated with fish farming: For example, the pellets used to feed the fish are actually made from small fish caught in the wild. In order to keep larger numbers of these important fish in the food chain, experts are now finding alternative

ingredients for fishmeal.

Another concern is that too many cages in the wrong location can lead to water pollution.But experts are now using computer models to map out sites where cages would have less

environmental impact.

Fish farming can generate jobs and profits here at home.And with the use of new technologies, it can also safely and sustainably meet the demands of a seafood hungry nation.