Category Archives: Fish

Insomniac Cavefish Might Hold Clues to Sleep Disorders in Humans

Mexican Blind Cavefish

Mexican blind cavefish

Sightlessness is a common adaptation of cave-dwelling animals. Sometimes, as in the case of the Olm eyeless cave salamander or “human fish,” they no longer even have eyes. Now scientists have learned that at least in a certain kind of cavefish, the Mexican blind cavefish, sleep, too, is a waste of resources.

Well, that’s not quite the right way to put it. It’s not so much that the fish don’t need sleep, it’s that they need to stay awake more, said the researchers in a press release.

“These fish live in an environment where food is generally scarce,” said Richard Borowsky of New York University. “If you are asleep when a bit of food floats by, you are out of a meal and out of luck.”

Borowsky and lead author of the study Erik Duboué first observed hints of the insomniac tendency of cavefish in the laboratory. Fish that typically hang out in brighter surface waters showed obvious sleep patterns. At night, they would get droopy fins and sink to the bottom of their tank. Captive cavefish on the other hand kept patrolling around the clock.

Cross breeding cavefish with other fish has shown that the wakefulness is genetic. Besides the gee whiz factor of the find, scientists think that this cave critter could hold clues to understanding sleep disorder in humans. That’s because the same gene that keeps the fish partying all night long, is likely also the gene that regulates similar behavior in other animals.

Scientific Journal:

Current Biology, April 7 issue

Authors and Affiliations:

Richard Borowsky of New York University

Erik Duboué of New York University

Contact:

Elisabeth Lyons, elyons@cell.com, 617-386-2121


Changing Chesapeake Bay acidity endangers oysters

New research shows that the shell growth of Crassostrea virginica from Chesapeake Bay could be compromised by current levels of acidity in some Bay waters. (Photo/Chris Kelly, UMCES Horn Point Laboratory)

Growing up at the mouth of the Lynnhaven River in Virginia, where the river meets the Chesapeake Bay and the bay meets the ocean, I can’t tell you how many mornings I woke up and looked out my window to see neighbors wading in rubber boots, harvesting oysters from the beds just off our riverbank. For some, like my neighbors, oysters were a way to connect with the land and make a little extra dough. For others it was their livelihood. The act was something that just was. It never occurred to me that the oysters could one day be gone.

That’s why I was especially alarmed to read this new report from the University of Maryland Center for Environmental Sciences. Rising acidity levels in the Chesapeake Bay are making it harder for oysters to grow their shells. I’ve heard the news before that rising ocean acidity from sources such as carbon dioxide can spell disaster for marine wildlife, but this new study shows that acidity is rising faster in the Chesapeake Bay than in the ocean and having a measurable impact on Bay wildlife.

“With oyster populations already at historically low levels, increasingly acidic waters are yet another stressor limiting the recovery of the Bay’s oyster populations,” said marine biologist Dr. Roger Newell of the UMCES Horn Point Laboratory in a press release.

But don’t turn around to blame climate change just yet. The story is a bit more nuanced than that, though the source of the problem still has to do with us. In the saltier areas of the bay, the acidity is going up, leading to thin shell growth that makes oysters more vulnerable to predators, including crabs. But in more freshwater portions of the Bay, acidity is actually going down, said the study, which looked at more than 20 years of historical water quality data from the Bay.

The difference seems to be not atmospheric carbon dioxide, but the base of the food chain. In freshwater areas along the upper Chesapeake, sewage and agricultural runoff cause phytoplankton blooms, which consume carbon dioxide and lower acidity, said the study. Sounds good at this point right? Here’s the catch. As phytoplankton drift through the Bay, they are eaten by animals and other bacteria, releasing the carbon dioxide that the plankton so diligently consumed in the first place. This carbon dioxide lingers in the water, leading to spikes in acidity in the saltier regions of the Bay near the ocean.

“While these variations in acidity may improve conditions for shellfish in some areas, they may also magnify detrimental impacts in others,” said lead author Dr. George Waldbusser of Oregon State University in a press release. “What our study indicates is there may be an important shifting baseline and without better measurements we will fail to fully understand impacts on estuarine biota.”

Beyond the science itself, this study highlights how connected and varied our environment is. It lays out a pathway of human-induced consequences to an ecosystem, and teaches that we need to look beyond one-to-one cause and effect. Erin Voigt, an undergraduate student who worked on the study puts it well. “The complex response of oyster shell formation to temperature, salinity, and acidity highlights the need to understand how the entire ecosystem is changing, not just acidity,” she said.

And that ecosystem includes us.

You can view the article online in the journal Estuaries and Coasts.


Could a proposed EU ban on discarding bycatch threaten seabirds?

Northern gannet picture taken at bird colony of Helgoland, North sea, German Bight, May 2002. (Photo/ Michael Haferkamp)

You know the scene. A commercial fisherman hoists a net roiling with flip-flopping fish. Clouds of seabirds swarm and fill the air with a greedy squawking, their beaks hungry for unwanted catch.

That raucous chorus may get a little quieter soon as birds are forced to seek their feast elsewhere. In a move aimed at curbing the devastating environmental consequences tied to commercial fishing, the European Union looks to consider new restrictions that would ban the discard of unwanted fish. The rule could be a win for fisheries conservation, but in a twist of good intentions, could also risks endangering the gannet, a seabird that thrives on bycatch tossed overboard.

Fisheries have dealt more than one blow to seabird populations as birds compete for resources or risk becoming ensnared in equipment. One of the few successful species, the gannet, has adapted to exploit the leftovers of commercial fisheries, swooping in on fish and other creatures thrown aside and left behind.

Dr. Keith Hamer, a researcher with Leeds’ Faculty of Biological Sciences is leading a team of researchers that will study the gannet and assess the possible consequences of imparting a ban on discarding unwanted catch. “Although discards should be stopped to protect marine biodiversity, research is needed on the impact of a ban, so policy makers can understand the best way to implement it,” said Hamer in a press release.

The study will especially look to better understand how gannets rely on bycatch for raising chicks. Past research indicates that breeding pairs may prefer different menus with some birds relying mostly on discards from fishing boats and others seeking out sand eels or diving for mackerel and herring. “We think gannets have different aptitudes and specialities and for some, that skill might be finding and following fishing boats,” said Hamer.

So if gannets feel like they’re being watched, they’re not so far off. Researchers plan to catch and tag breeding pairs from 12 colonies throughout the United Kingdom. Hamer along with scientists Stephen Votier of the Marine Biology & Ecology Research Centre at the University of Plymouth, and Stuart Bearhop, with the University of Exeter, will keep tabs on the birds’ locations, diving patterns, diet and nests.

“Although the long-term benefits of a ban will be positive, we need to accurately predict short-term impacts as well,” said Hamer. “If gannets have specialised to the extent we believe, rather than cut off a crucial food source overnight, a gradual phasing in of the ban would allow them time to retrain to find food elsewhere.”

Hopefully this thinking ahead will help prevent a new conservation crisis from cropping up even as the EU takes steps to solve another.


Backcountry trek to study Rocky Mountain National Park fish introductions

more about “Backcountry trek to study Rocky Mount…“, posted with vodpod

 

At the risk of sounding arrogant, I have to say that I have one of the coolest jobs in the world. I work as the science writer for CIRES, the Cooperative Institute for Research in Environmental Sciences. My job doesn’t stop at writing about science. Being a photographer and multimedia producer play equal parts.

In this instance, I got to hit the trail with Jimmy McCutchan and Tommy Detmer, a couple of CIRES scientists studying the effects of fish introductions on formerly fishless lakes of Rocky Mountain National Park. Fish were introduced to support fly fishing from the 1800s until the 1960s. Now the National Park Service is working with CIRES to find out what’s happened to those lakes, knowledge that may help guide future management.

Their study also isn’t a bad way to work a little fly fishing into your science.

You can learn more about CIRES science at cires.colorado.edu, or check out the CIRESvideos channel on YouTube.com.

 


Oops! Endangered tuna unwittingly served at sushi restaurants

Yellow fin tuna (Thunnus albacares) and short-beaked common dolphin in a diorama of the eastern tropical Pacific at the AMNH's Milstein Family Hall of Ocean Live. (Image/R. Mickens/AMNH)

Next time you head out to your favorite sushi restaurant, you might want to think twice about ordering the tuna. There’s a good chance the fish on your plate could be an endangered species.

A new study by the American Museum of Natural History conducted DNA investigations on tuna at restaurants in New York City and Denver and found that nearly 30 percent of the tuna tested was actually endangered bluefin, and less than half of that was labeled as such.

A single bluefin tuna can sell for tens of thousands of dollars at market, a popular draw for the fishing industry. But that popularity comes with a price. Western stocks of northern bluefin tuna now hover around 10 percent of their “pre-exploitation” numbers. And last October, the country of Monaco nominated northern bluefin tuna for a listing under a complete international trade ban by the Convention on International Trade in Endangered Species (CITES), according to a press release.

The serving up of a critically endangered fish is not necessarily on the shoulders of the restaurants. They might not know they’re doing it, just as consumers might not know they’re eating it. This is because the eight species of tuna are so genetically similar – closer than humans are to chimpanzees – that even with DNA testing, it’s hard to distinguish the difference, and once tuna arrives to the U.S. market, the U.S. Food and Drug Administration-approved marketing label is simply “tuna.” A new and improved method of genetic detective work just might help change all that.

“When you eat sushi, you can unknowingly get a critically endangered species on your plate,” says Jacob Lowenstein, a graduate student affiliated with the Museum and Columbia University in the press release. “But with an increasingly popular technique, DNA barcoding, it is a simple process for researchers to see just what species are eaten at a sushi bar.”

DNA barcoding can be used to identify what animal became which product, even down to the origin of a leather handbag, according to the press release. In the case of the bluefin tuna, DNA barcoding defines a genetic key of 14 nucleotides exclusive enough to identify whether the tuna being served is bluefin. A similar method has been used to identify endangered whales on the Asian market and wildlife being sold in the African bushmeat trade.

With any luck, researchers will develop a handheld barcoding machine that can be used to identify fish on-site.

This study can be found in the current issue of PLoS ONE.


What is Conservation Photography?

You can tell when someone puts their heart into something. And young conservation photographer Hunter Nichols is one of those people. The camera is but a tool to help save a place that he loves, Alabama’s Cahaba River, an ecosystem falling apart under the stress of increasing urbanization.

more about “What is Conservation Photography?“, posted with vodpod

Conservation photography goes beyond iconic beauty shots of nature, connecting us with these places and their struggles for survival. Nichols not only takes us through a dream-scape river echoing with a cacophony of birds and wildlife, but shows us the active clear-cutting, new neighborhoods and environmental consequences of rapid urban sprawl. As Nichols says in his video, “we never miss something we never knew, but we suffer from what we’ve lost.”

Then again because of people like Nichols, we not only learn of the unknown places, but just might get to one-day experience them for ourselves. Watch this short video to see what Hunter is trying to protect, and learn a little something about conservation photography.


You can view more of Nichols’s work at hunternichols.tripod.com.


Bait fisheries drive decline of bird species

(Photo/Andrew Easton, 2004)

(Photo/Andrew Easton, 2004)

Every year the horseshoe crabs gather to spawn, releasing thousands of eggs along the Delaware Bay coast. And with timing perfected by evolution, red knots, a bird enduring one of the most impressive yearly migrations from the Arctic to the Tierra del Fuego, arrive just in time to gorge on the eggs of the horseshoe crab. It is a vital stop on the “peeps’” spring migration. But the crabs and their eggs are disappearing, a loss with dire consequences for the little birds.

Red knot populations have fallen more than 75 percent in recent years, and new research published in this month’s issue of Bioscience reveals that Red knots can thank the bait fisheries for their hungry stomachs. Within half a decade the fisheries harvesting horseshoe crabs grew 20-fold, gobbling up more than 2 million crabs a year and effectively eliminating 90 percent of the eggs that red knots rely upon to survive their almost 19,000 mile migration.

But this research is not just a blame game for the fisheries. A coalition of scientists worked together on this study to help draft recommendations for the adaptive management of the bait fisheries that could help all three groups survive.


Woe betide the lovesick lamprey

Love is in the water, and the lamprey swears she’s found her match. She swims the corner ready to score. That’s when they spring the trap. 

Scientists out of Michigan State University are using chemical trickery to seduce and capture female sea lampreys, a devastatingly invasive species found in the Great Lakes. A single lamprey can eat up to 40 pounds of fish, and they’re to blame for the extinction of at least three whitefish species.  The voracious predators have proven difficult and expensive to control, costing the U.S. and Canadian governments $10 to $15 million a year.

But males it turns out, release an irresistible chemical into the water attracting females from more than a hundred meters away, and this mojo might just be the key to the lamprey’s undoing.  Weiming Li, a professor of fisheries and wildlife at MSU, and his team spent years isolating and synthesizing a fake version of sea lamprey love potion. Now they’ve landed on a treatment that is as effective as the lamprey’s own and when used in small doses could effectively treat sea lamprey infested waters. 

“The commission considers regulating spawning and migrating behavior with pheromones the most promising control method for implementation,” Li said in a press release. “So we’re excited about the possibilities.”

You can learn more about this promising new treatment method in the latest version of the Proceedings of the National Academy of Sciences.


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