Science – Page 26 – Southern Fried Science

Seals use signals from acoustic tags to find fish

December 4, 2014December 8, 2014 Michelle Jewell

Michelle Jewell is a Zoologist specialized in predator/prey behaivour and the Scientific Communicator for EDNA Interactive. She has spent the past 4 years studying the behaviour of white sharks and Cape fur seals at Geyser Rock, ‘Shark Alley’, South Africa.

Anyone who has worked with seals knows they are crafty critters that will always find the easiest way to eat fish. Take the rise and fall of acoustic deterrent devices in aquaculture farms that were designed to scare away seals and other predators. They had limited success and resident predators habituated to the sound when they realized there was no immediate danger. These devices have been shown to actually attract more predators over time, especially passing pinnipeds.

Scientists have used acoustic tags to monitor fish movements since the 1950s, and hundreds of species have been implanted with these tags (a ‘few’ studies listed here) throughout rivers, lakes, estuaries, and the ocean. Could marine mammals associate tag signals with food and do they do this in the wild? A recent laboratory study from St. Andrews (free to download here) answers the first half of this question, showing that grey seals Halichoerus grypus were able to use the signals transmitted from Vemco V9–2H tags to identify boxes that contained fish.

Agents of seal: stealthy seals use subsurface structures to sneak by sharks

November 18, 2014December 8, 2014 Michelle Jewell 1 Comment

Blogging, Science

Predators are highly influential in ecosystems because of the many top-down effects they can have. The most obvious and direct way predators influence an ecosystem is by eating and reducing the number of prey animals in the system, but another equally important way is the indirect influence they have on the behaviour of prey animals.

If you have avoided parking on a risky-looking street, taken a different route between classes to avoid a bully, or abandoned a forest hike because of snapping twigs in the distance, you have been indirectly affected by perceived ‘predators’. In the wild, prey animals will also change their behaviour when they perceive that predators are around, and these altered behaviours often influence other species, ultimately shaping the ecosystem.

Fun Science FRIEDay – The Origin of HIV

November 14, 2014November 25, 2014 Kersey Sturdivant

Blogging, Science

Happy Fun Science FRIEDay

After a hiatus, I hope to get back to regularly writing these pieces. This week I was particular inspired to focus on an article I read about the discovery of the origins of the human immunodeficiency virus (HIV) and subsequently the origins of AIDS.

Scanning electron micrograph of HIV-1 (in green) budding from cultured lymphocyte. Multiple round bumps on cell surface represent sites of assembly and budding of virions. Photo Credit: Centers for Disease Control (CDC) — Scanning electron micrograph of HIV-1 (in green) budding from cultured lymphocyte. Multiple round bumps on cell surface represent sites of assembly and budding of virions.
Photo Credit: Centers for Disease Control (CDC)

AIDS burst onto the scene like a bat out of hell, wreaking havoc on an unsuspecting human population. First recognized in the early 1980s by the Centers for Disease Control and Prevention, better known as the CDC), AIDS went on to cause approximate 36 million deaths globally becoming one of the most devastating diseases in human history. But where did this affliction come from and what were the chain of events that led to the pandemic?

Marine Ecology via Remote Observation: an update from #ROV2PNG

November 12, 2014November 12, 2014 Andrew Thaler

Science

Note: we’re home after an exceptional 3 weeks of work in Papua New Guinea. Sadly, the course was so intense that we weren’t able to produce updates during the program. Instead, please accept these time-shifted updates from #ROV2PNG. After more than a week of building robots, developing research proposals, presenting and defending their proposals to … Read More “Marine Ecology via Remote Observation: an update from #ROV2PNG” »

Newly-build robots face many sea trials: an update from #ROV2PNG

November 10, 2014 Andrew Thaler

Science

With a week of robot building behind us, it’s time to put our robots, and our newly minted robot pilots to the test. Monday began with a day of tether management and pilot training. The OpenROV does not come with its own, pre-built tether management system; operators must design their own and adapt it to the unique challenges of their field environment. So we set the team off to develop their own tether management systems and the results were astounding, artistic, and clever.

One of several innovative tether management systems.

With tethers securely managed, it was time for Erika’s Pilot Academy. As some teams continued to perform maintenance and troubleshooting, and some worked on their ecology projects, others were led, group by group, to the test tank, where Erika and Dominik had built a challenge course for them to fly. Without looking at the tank or robot, each student had to pilot an ROV around the tank, collect a weighted target, and bring it to the surface. Even for veteran OpenROV pilots, this exercise can be challenging. We closed out the first day of pilot training with 23 skilled pilots.

Watch Outbreak Wednesday at 8 and tweet along with public health experts!

November 10, 2014 David Shiffman

Popular Culture, Science

Much of the public panic about the current ebola situation can be contact traced to the 1995 movie “Outbreak.” This fictional movie is based on the supposedly true story “the Hot Zone” by Richard Preston , though an important new analysis by infectious disease researcher Dr. Tara Smith shows that the Hot Zone has some major factual … Read More “Watch Outbreak Wednesday at 8 and tweet along with public health experts!” »

Six new robots join Papua New Guinea’s marine science assets: an update from #ROV2PNG

November 7, 2014November 6, 2014 Andrew Thaler 1 Comment

Science

Students prepare to soak test their ROV.

After a long week of intensive robot building, six brand new OpenROVs went into the water on Friday. Our student’s hard work paid off as their robots dove into the freshwater test tank. There are few things more rewarding than watching students, who’ve sweated over a difficult build while learning challenging new skills for 12 hours or more every day, launch their completed robots drive them around the test tank for the first time.

Of course, failure is part of our pedagogy, and two robots will require another day of troubleshooting before they can be released into the sea.

Dominik sets up the Chromebooks for their first flight.

Media coverage of the Yates Supreme Court case isn’t treating illegal fishing seriously

November 6, 2014 David Shiffman 1 Comment

Conservation, Science

This week, the Supreme Court heard oral arguments for Yates vs. the United States. Commercial fishermen John Yates was caught with dozens of illegally caught grouper, he destroyed much of the evidence of this crime, and he was charged under a law designed to prosecute people for destruction of evidence. He is now suing the government for overreach.

The question of whether a law most commonly known for being used to deal with destruction of financial records can also be used to deal with destruction of evidence of illegal fishing is an interesting one. The Obama administration claims that the law was designed to be a generic Federal destruction of evidence ban, and it has also been used, according to a USA Today article, to “go after the destruction of cars, cash, cocaine, child pornography- even murder weapons and bodies.” It seems to me that it is an appropriate role of government to write regulations to ensure that our shared natural resources are sustainably exploited, it is an appropriate role of government to enforce violations of those laws, and it is an appropriate role of government to punish people for destroying evidence of those violations. A much bigger problem, however, is with much of the media coverage of this case.

Progress: It’s now only legal to remove fins at sea for one shark species in the United States

November 3, 2014November 3, 2014 David Shiffman

Conservation, Science

Shark finning, the process of removing shark fins at sea and dumping the rest of the body, is nearly universally opposed by conservation activists, scientific researchers and fisheries managers. In addition to being potentially inhumane (the shark is often still alive when dumped overboard,) this processing method is exceptionally wasteful and makes it very difficult for fisheries managers to get accurate species-specific catch data.

There are severals ways to stop shark finning. One is to ban fishing for sharks entirely, fins of sharks can’t be removed at sea if sharks aren’t caught in the first place. It is important to note that some well-intentioned activists use “stop shark finning” as a synonym for “stop shark fishing of any kind,” but that is unequivocally not what shark finning is and not what finning bans accomplish. The second method is through the use of fin to carcass ratios. Under these policies, fisherman can remove the fins of sharks at sea as long as the total weight of fins landed does not exceed a certain percentage (usually 3.5 to 5%) of the total weight of carcasses landed. This can still leave room for some undetected finning (these ratios vary by species and fin removal method) and still makes it difficult for managers to know how many of each species are being caught (sharks are more readily identifiable when their fins are intact). Finally, a method growing in popularity in recent years, which is generally considered to be a best practice of shark fisheries management, is the requirement of landing all caught sharks with “fins naturally attached.”

More large sharks were killed by recreational anglers than commercial fishermen in the U.S. last year

October 29, 2014October 29, 2014 David Shiffman 2 Comments

Conservation, Science

The United States National Marine Fisheries Service just released the 2013 “fisheries of the United States” report. The extremely detailed report contains lots of important information on both recreational and commercial fisheries in U.S. waters, and I recommend giving it a thorough read. I noticed an interesting detail about the U.S. shark fishery, though. In 2013, more large (non-dogfish) sharks were landed by U.S. recreational shark anglers (~4.5 million pounds) than by U.S. commercial shark fishermen (~3 million pounds). This was not the case in 2012.