Almost half of the world’s seafood now comes from fish farms, which can cause significant environmental harm if not responsibly managed.
Because many fish are confined to a small area, aquaculture can lead to high levels of pollution and outbreaks of diseases. Sometimes the farmed fish escape, which can hurt wild fish populations and the local ecosystem. Aquaculture can also lead to overfishing since carnivorous fish, like salmon and tuna, are fed large amounts of fishmeal made from prey fish like anchovies or herrings.
The Velella Project is an experiment off the coast of Hawaii that is trying to address some of the problems associated with aquaculture. Instead of enclosing fish in stationary nets or tanks like traditional farming methods, a specially-designed spherical pen, called the Aquapod, drifts through the water containing 2,000 hatchery born fish.
In the last three months, more than 3,000 dolphins have washed ashore in Peru, most likely due to offshore oil exploration. Oil companies in the region often use sonar or acoustic soundings to detect oil beneath the floor of the sea, and dolphins and whales can be affected because of their sensitivity to sound.
Toothed whales, including dolphins and porpoises, have evolved to be able to echolocate. Instead of having two nostrils like other mammals and baleen whales, toothed whales have only one which is used as their blowhole. A whale emits squeaks and whistles from its blowhole, and the sounds bounce off objects in the water, providing an echo. The other nostril has developed into a fatty tissue known as the melon, which is used to receive and focus the returning echoes.
Hearing is considered to be whales’ most important sense, used not only for navigating but also for feeding, bonding with offspring, and finding mates. Noise pollution cause changes in calling behavior, but can also cause whales to change their diving habits which can result in “the bends,” when nitrogen bubbles get trapped in the body.
Sonar can be extremely loud (imagine the sound of 2,000 jet planes), with sound waves travelling hundreds of miles through the ocean. Noise levels this high can cause fatal injuries, similar to those seen in many strandings around the world. As the world’s oceans become noisier, they also become more dangerous for whales and dolphins.
Every year, tens of millions of sharks are killed for their fins alone. Shark fins are used to make shark fin soup, a popular and expensive dish that is a symbol of wealth and status primarily in Asian cultures.
The demand for fins can lead to cruel and wasteful practices, such as cutting off a shark’s fins at sea and then throwing the rest of the shark, sometimes still alive, back into the water. And shark fin soup can be dangerous to humans. Since sharks are at the top of the food chain, they accumulate toxins like mercury, which is a dangerous neurotoxin.
So are there any alternatives to shark fin soup? Shark fins themselves have no taste and are used only for texture. In traditional shark fin soup recipes, chicken or fish stock is added to give the soup flavor which means that there are a lot of ways to enjoy shark fin soup without using shark fins – like this recipe from the Monterey Bay Aquarium:
Each of the six sea turtle species found in the United States are listed as endangered or threatened under the Endangered Species Act. Every day, sea turtles face a number of threats including pollution, boat strikes, hunting, accidental capture by fisheries, as well as the development of many coastal beaches that female sea turtles use for nesting sites.
But a growing threat to sea turtles is climate change. Rising sea levels and increased numbers of storms will likely limit the number of beaches that are suitable for nesting, and warmer temperatures could have a significant effect on sea turtle reproduction since the sex of sea turtle eggs is determined by the nest temperature. Warmer sands will result in more females, while cooler sands favor males. The magic temperature seems to be about 82°F, but this can vary depending on the species.
Temperatures are predicted to rise by 2.5-10°F in the next century, which could alter hatchling sex ratios especially in areas that are already warm like the Caribbean. In Florida, loggerhead nests are already producing more than 90% females, and further warming could mean that no males hatch from these nests at all.
In a new study, however, a group of researchers used screens to shade nests, and they found that it effectively reduced nest temperatures and produced a higher proportion of male hatchlings. By protecting beaches where males are more common and by applying artificial shading, if necessary, a healthy ratio of male and female sea turtles will be born.
Although shading may provide some relief to sea turtle populations already threatened with extinction, it is only a temporary solution to a much larger problem. To help take action against climate change, here are a few steps you can take at home and in your community.
According to new estimates, farmed shrimp from Asia may have one of the highest carbon footprints of any food.
More than half of all shrimp farms are located in Asia, primarily in areas that used to be mangrove forests. Mangroves are trees that grow in salt water, and they are important for marine ecosystems because they provide nutrients and shelter for many fish, turtle, and wading bird species. Mangrove forests are also important because they serve as a carbon sink, removing and storing more than 1,000 pounds of CO2) per acre each year.
But around the world, mangrove forests are being cut down to build shrimp farms. These farms are also often short-lived. The intensive farming methods pollute the environment, and disease spreads easily among the shrimp, which means that shrimp farmers must frequently clear new areas to stay in business.
Today, the Maryland state Senate Education, Health, and Environmental Affairs Committee is holding a hearing on numerous bills including a bill that would ban the possession, sale, trade and distribution of shark and ray fins.
This bill will help protect global shark populations by reducing the demand for their fins. Each year, tens of million sharks are killed so that their fins can be used in shark fin soup. In the United States, the cruel and wasteful practice of shark finning is illegal. However, many fins are imported from all around the world, contributing to the demand for shark fins and the overfishing of sharks.
Hawaii, Oregon, Washington, and California have already passed similar laws, and bills have also been introduced in New York, Illinois, Florida, and Virginia. Oceana supports Maryland’s initiative and asks that state residents do so as well.
Please show your support by telling your legislator to vote for SB 465!
When sea turtles are sick or injured, they can spend a few weeks or months recovering in sea turtle rehabilitation or research centers. The turtles are released back into the wild as soon as they have recovered enough so that they can live normally in the ocean.
But sometimes, sea turtles spend years or even decades away from the ocean. Still, even after sea turtles have spent long periods of time in captivity, they are able to return to the ocean and live like a wild turtle – even following complex migration routes.
Wild sea turtles migrate long distances to reproduce, as females return to the same beach where they hatched in order to lay their own eggs. Sometimes, these turtles cross entire oceans to get back to the beach where they were born. These long journeys inspired the Great Turtle Race, where leatherback sea turtles were tracked as they crossed the Pacific Ocean to nest.
Although not all sea turtles can be released from rehabilitation, healthy turtles that have spent a long time in captivity can still easily adapt back to ocean living. In 1996, researchers released a female loggerhead named Adelita, who had been raised in captivity for 10 years.
Researchers attached a satellite tracking device and were able to follow her incredible journey from Baja California to nesting sites in Sendai Bay, Japan – over 7,000 miles away! Even though she had spent her entire life in a research facility, she was still able to find her way to the area where she hatched.
Plastic is one of the most common pollutants that end up in the ocean, but the properties that make it ideal for shopping make it deadly to marine life.
Plastics are durable and do not decompose easily, which means they can stay in the ocean for decades. And because they are so lightweight, plastics can float in the ocean where sea turtles and marine birds can get entangled or even ingest them by mistake. For example, plastic bags in the ocean closely resemble jellyfish, which are a common food for sea turtles.
Plastic can also have serious effects on marine mammals, including sperm whales which are some of the world’s smartest animals – possessing the largest brain of any known species.
Sperm whales typically feed on squid, sometimes diving more than a mile below the ocean’s surface to find food. But plastic trash is becoming more and more a part of the whales’ diets. Each year, sperm whales eat more than 100 million tons of seafood using suction, which makes them more vulnerable to ingesting plastic. And because sperm whales are at the top of the food chain, they are the most likely to be affected by pollution.
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