Perhaps the most important message the Discovery Channel’s Shark Week can deliver is not how sharks may be dangerous, but how these fantastic fish are in danger.

While it’s hard to estimate the total number of sharks killed each year by humans, due to the illegal and unregulated nature of practices like shark finning, some studies put the number at around 100 million per year, says Shark Stewards’ founder David McGuire. The World Wildlife Fund reports that this number is also growing at about 5% each year.

McGuire, also an Academy research associate and a lecturer at the University of San Francisco, calls himself a “conservationist with science training” who hopes to spend the rest of his life protecting sharks.

He earned his shark chops here at the Academy, working with, and learning from, the amazing John McCosker, who has spent his life swimming with fewer and fewer sharks.

McGuire began telling his shark tales with a documentary in 2006 called “Shark Stewards of the Reef,” documenting the connection between sharks and coral reefs and highlighting the important role these top predators play in supporting the health of coral reefs.

A few years later, he was on the front lines of the shark fin ban here in California, which was successfully passed into law in 2011.

As McGuire has watched more states join the ban and other organizations get involved here in the United States, he’s moved his sights to Asia, to create more awareness about the plight of sharks worldwide. He’s working with eco-tourism and ecosystem restoration organizations, as well as focusing on educating a public that might consume sharks and shark fins without truly understanding the consequences to the health of the fish and the oceans in general.

After returning from a three-week trip to Cambodia, Malaysia, and Hong Kong, McGuire stopped by the Academy this week to give us an update on his work. “The idea is to bridge American relationships and resources to small grassroots organizations in Asia, as well as bring the message of shark conservation in a good way, not pointing fingers. We want people to have the information to make better decisions,” he explains.

Shark Stewards recently joined the Earth Island Institute in order to further its cause. McGuire is working on ads and videos providing solutions to the overhunting of sharks and recently organized two “Swim for Sharks” awareness events—3.5 mile swims here in San Francisco and also in Hong Kong, the center of the shark fin trade.

McGuire won’t stop in the fight for shark conservation. “It’s daunting,” he says of the work ahead in Asia, “but it’s also exciting.”

Follow McGuire’s work on his blog.

Image: David McGuire

Top predators (think sharks, lions, wolves) may eat many animals within an environment, but they also keep the ecosystem in check.

This may seem counter-intuitive, but according to science writer Mary Ellen Hannibal, “We need a full complement of species on wild landscapes so that nature can fulfill its whole cycle.  It turns out that top predators—the wolf, for example—play an outsize role in keeping the whole system together.”

This was, in fact, the subject of her very excellent OpEd piece in the New York Times last fall entitled, “Why the Beaver Should Thank the Wolf.”

And scientific studies reflect this, too. A study out this week in the Journal of Animal Ecology demonstrates why the grizzly bear should also thank the wolf.

Bill Ripple, Bob Beschta, and their colleagues discovered that the return of wolves to Yellowstone National Park is beginning to bring back a key part of the diet of grizzly bears that has been missing for much of the past century—berries that help bears put on fat before going into hibernation.

“Wild fruit is typically an important part of grizzly bear diet, especially in late summer when they are trying to gain weight as rapidly as possible before winter hibernation,” Ripple says. “Berries are one part of a diverse food source that aids bear survival and reproduction, and at certain times of the year can be more than half their diet in many places in North America.”

Looking at bear scat, the researchers found that the level of berries consumed by Yellowstone grizzlies is significantly higher now that shrubs are starting to recover following the re-introduction of wolves, which have reduced over-browsing by elk herds. The berry bushes also produce flowers of value to pollinators such as butterflies, insects, and hummingbirds; food for other small and large mammals; and special benefits to birds.

When wolves were removed from Yellowstone early in the 1920s, increased browsing by elk herds caused the demise of young aspen and willow trees—a favorite food—along with many berry-producing shrubs and tall, herbaceous plants. The recovery of those trees and other food sources since the re-introduction of wolves in the 1990s has had a profound impact on the Yellowstone ecosystem, researchers say.

Hannibal points out that Beschta and Ripple didn’t set out to study wolves. In an email to Science Today, she says, “They set out to study the health of the Lamar River… But in looking for a cause to explain the degradation of the river, what they found is that super-abundant elk were eating the vegetation down to the roots on the river banks, and the vegetation wasn’t able to ‘recruit,’ or grow up strong and healthy. When wolves were reintroduced to Yellowstone, the vegetation started to recover. Beschta and Ripple and many other scientists documented this and analyzed it, and it turns out that elk change their behavior when wolves are around, and they stay on the move, which gives the vegetation time to recover.”

“Studies like this point to the need for an ecologically effective number of wolves,” Beschta says in a press release. “As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health.”

Beschta’s and Ripple’s work is featured in Hannibal’s Spine of the Continent, a great story of conservation efforts to create wildlife corridors to protect these top predators and the ecosystems that depend on them. Look for more of these stories here in Science Today, and in an Academy exhibit, Life Connected, opening in Spring 2014.

Image: Bobisbob at en.wikipedia

Villy Christensen of the University of British Columbia (UBC) said, “Yes, there will be fish left, but it will be a very different ocean from the ones your parents and grandparents knew and even different from now.”

The biggest difference? Large, predatory fish will be gone.

In fact, over the last one hundred years, the population of these large, top-of-the-food-web fish has declined by two-thirds, half of that decline occurring only in the last 40 years. And that population continues to decline.

There will be many small fish left, but not necessarily the ones we eat.

He and his colleague, Reg Watson, also from UBC, are working with scientists, governments and NGOs to build a global database of fishing efforts to truly understand what’s going on in the world’s oceans.

Seventy-six million tons of fish are consumed each year, and Watson found that we are fishing harder for the same or less result. It’s possible that we’ve hit “peak fish,” according to Watson. Jacqueline Alder of the UN Environment Program in Kenya is working with the UBC group, looking at their models in terms of marine biodiversity and sustainability. She urged that we must reduce fishing efforts immediately to allow fish stocks to rebuild.

In addition, there was much discussion around the non-sustainability of using fish for feedstock in aquaculture and agriculture– fish we are not directly eating. The science and technology have to get better to use plant-based feedstock for fish farms.

Christensen stressed this is a large view of what’s going on in the entire ocean ecosystem, not just one area or species.

For more focused, local information, read our recent article on banning shark finning, and the San Francisco Chronicle had a devastating article last week stating that some of the fish in the Delta may be too far gone to save from extinction.

Image: Mila Zinkova/Wikimedia