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Orcas Versus Boats | Earth Wise

July 11, 2023 By EarthWise Leave a Comment

Over the past three years, orcas (also known as killer whales) have been attacking boats off the coasts of Portugal and Spain. The subpopulation of orcas in this region has been harassing boats, most often by biting at their rudders.

There have been over 500 reported instances of orcas reacting to boats. Sometimes they simply approach the vessels, but some of the time they actually attack. Almost 20% of the attacks have caused enough damage to disable the vessels. In three cases, including one in May in the Strait of Gibraltar, the animals damaged a boat so badly that it sank. To date, no one has been injured during these attacks.

Orca researchers have observed several different killer whales during these attacks. They seem to come from two separate groups: a trio of juveniles occasionally joined by a fourth, as well as a mixed-age group consisting of an adult female, two of her offspring, and two of her sisters. The attacks typically last less than 30 minutes but can go on for up to 2 hours.

Researchers don’t really know why orcas are going after watercraft. This behavior has not been observed anywhere else in the world. One theory is that the orcas have invented a new fad. That’s actually something that they are known to do. Much as with people, orca fads are often spearheaded by juveniles. An alternative theory is that the attacks may be a response to a bad past experience involving a boat. The fact that nobody has been injured in any of these attacks, even when the boats sank, suggests that only the boats themselves are the target of the attacks and not the people on them.

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Why Has a Group of Orcas Suddenly Started Attacking Boats?

Photo, posted May 24, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Humanity Weighs On The World | Earth Wise

April 6, 2023 By EarthWise Leave a Comment

There are countless ways in which humankind has had disproportionate effects on our planet and most of those effects have been negative. A recent study led by the Weizmann Institute of Science in Israel looked at the total combined weight of various groups of mammals on Earth. The results are that human beings and our domesticated mammals are the overwhelming majority of the total mass of mammals.

We think of large land mammals – elephants, bears, bison, wildebeests, and so on – as adding up to a massive amount of animal matter. The study determined that all wild land mammals put together add up to about 22 million metric tons. Wild marine mammals – such as dolphins and whales – add up to about 40 million tons in total. These sound like pretty big numbers until we look at the human and human-created side of the equation.

The study found that humans weigh about 390 million metric tons, while domesticated mammals – like sheep, cows, and pigs as well as dogs and cats – weigh about 630 million metric tons combined.

All told, wild mammals account for only 6% of all mammals by weight. People and their domesticated animals make up the other 94%. This enormous imbalance is an indication of how profoundly humans have reshaped life on Earth. House cats total twice the weight of African elephants and pigs add up to twice the weight of all wild land animals combined.

The conclusion to draw from the big picture here is that wild animals on Earth are not doing very well. We already knew this from many other perspectives, but this census by weight presents a stark picture of the extent to which we have taken over the planet and its ecosystems.

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Total Weight of Wild Land Mammals Less Than One-Tenth Weight of All Humans

Photo, posted December 27, 2006, courtesy of Nigel Hoult via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Spiders And Pest Control | Earth Wise

April 5, 2023 By EarthWise Leave a Comment

Climate change facilitates the spread of invasive pest species by expanding their habitable environment ranges. In conventional agriculture, farmers depend on chemical pesticides to control agricultural pests. But 99% of all synthetic chemicals, including pesticides, are made from fossil fuels, and turning petrochemicals into pesticides requires massive amounts of energy. These chemical pesticides also pollute the air and water, and destroy biodiversity by killing many non-target species as well.

According to new research led by scientists from the University of Portsmouth in the U.K., groups of spiders could be used as an environmentally-friendly way to protect crops against agricultural pests. The study, which was recently published in the journal Insects, suggests that web-building groups of spiders can be used to control populations of the tomato leafminer moth, a devastating pest of commercially important crops like tomatoes and potatoes.

The research team explored the use of tropical tent spiders for this pest control. They are found in colonies around the world, and their range overlaps with regions of moth infestations, including Mediterranean Europe, Africa, Asia, and the Middle East.

In lab settings, different types of prey were introduced to colonies of spiders of varying body sizes. The research team found that the larger spiders built larger webs and caught more prey, including tomato leafminer moths and fruit flies.

Tropical tent spiders could be an effective and climate-friendly way to control flying insect pests. However, more research is needed to ensure that these spiders don’t negatively impact crop pollination by also catching pollinators.

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Using spiders as environmentally-friendly pest control

Photo, posted June 10, 2018, courtesy of Lies Van Rompaey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Return Of The Fin Whale | Earth Wise

August 15, 2022 By EarthWise Leave a Comment

The fin whale is the second largest whale species and therefore the second largest creature on Earth. They can grow to more than 80 feet in length. From 1904 to 1976, there was massive industrial whaling in the Southern Ocean surrounding Antarctica. During that period, whalers killed about 700,000 fin whales, reducing their population by 99%. The species was nearly extinct.

In 1982, the International Whaling Commission voted to ban commercial whaling. Since that time, fin whales started to make a comeback in their historical feeding grounds.

During a nine-week expedition in the waters around the Antarctic Peninsula, researchers encountered the largest gathering of fin whales ever documented. About 150 fin whales were seen diving and lunging against the water’s surface. It was a feeding frenzy triggered by large amounts of krill in the water. The actions of the whales are known as a “whale pump” that drives the krill to the surface. Not only does it provide huge amounts of food for the whales but also for other animals, including seabirds and seals.

Forty years after the commercial whaling ban, the number of fin whales has been increasing. Large groups were observed in a 2013 survey. Aerial surveys in 2018 and 2019 recorded 100 groups of fin whales, usually composed of a just a handful of individuals. They did document eight large groups of up to 150 individuals.

Not all species of whales have rebounded so successfully since the whaling ban. The rebound in fin whale population is not only good for the whales, but for the entire ecosystem in the Southern Ocean. It is a glimmer of good news in a time of great challenges for global biodiversity and for marine life in particular.

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Once Facing Extinction, Massive Fin Whales Have Returned to Antarctic Waters

Photo, posted November 15, 2007, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

California’s Silent Health Hazard | Earth Wise

April 23, 2021 By EarthWise Leave a Comment

For people in the Los Angeles area, it is a familiar sight to see oil wells pumping away on hillsides, in residential neighborhoods, and other places. In fancier parts of town, oil wells are hidden behind facades located next door to dry cleaners and lamp stores.

Every year, more than 140 million barrels of oil are extracted from the state of California, coming from a vast subterranean formation that spans nearly the entire state along the coast and spreading inland as well. About 30% of the state’s oil comes from the Los Angeles area.

The oilfields are mostly old, and their wells played out. As a result, high-tech drilling and a slew of toxic chemicals are needed to extract the last dregs of crude oil.

Unlike more rural oil-producing states, where oilfields might be uninhabited except for the people who work on them, drilling in California happens to a large degree in residential settings. Over the years, it has become increasingly clear that certain chemical byproducts of oil extraction, among them benzene and hydrogen sulfate, can cause a variety of health problems. For example, recent research has found connections between exposure to oil and gas well sites and spontaneous pre-term births, low-birthweight babies, and other adverse birth outcomes.

Statewide, little is being done to protect residents and schoolchildren from any of the suspected consequences of living near an oil or gas well. Regulations are weak and spottily enforced because the oil industry still wields a lot of political power in the state. Environmental groups and justice advocates are actively seeking to create new protections for California citizens, but it remains an uphill battle.

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The Oil Well Next Door: California’s Silent Health Hazard

Photo, posted July 11, 2017, courtesy of John Ciccarelli / Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.