Could Asian carp thrive in Lake Michigan?
By Tony Briscoe/Chicago Tribune
Photo by Kate Gardiner/flickr
As Asian carp have stormed up the Illinois River in the past several decades,
looming precariously close to Lake Michigan
, scientists have been forced to ponder an alarming question: What if the invasive species actually breached the world’s fifth-largest lake?
Many fishery managers have already resigned themselves to the fact that bighead and silver carp, the two most-feared species of Asian carp, may never be eradicated from Illinois waterways, as a single female can lay over 1 million eggs each year. These insatiable fish have proved capable of eating 120% of their body weight in a day, mostly microscopic plankton — the base of the aquatic food chain. In doing so, they deprive other fish while growing to as much as 100 pounds by adulthood, much too large for any native predator to feed on them.
However, since the 1990s, invasive zebra and quagga mussels have devoured so much of Lake Michigan’s plankton that some experts have wondered whether Asian carp would be able to survive if they arrive here. Even if they could, some believe the carp would be limited to areas near shore where plankton is still plentiful instead of open water,
which has essentially become a food desert
.
A new University of Michigan-led study has turned that thinking on its head.
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Chesapeake’s crabs come back – for now
By Kristan Uhlenbach/National Wildlife
Photo by Chesapeake Bay Program/flickr
Backing up warily, bright red claws at the ready, the
blue crab
resembles a fighter—so picking her up requires a bit of technique (or a pair of thick gloves). Once she’s in your hands, look into her beady eyes. You might perceive a nervous glimmer, a hint that, while she is strong, threats to her home in the
Chesapeake Bay
—from
pollution
to warming ocean temperatures to rising sea levels—may make it harder for her to survive.
In this ongoing fight for survival, this year she came out on top. Results of the bay’s annual
winter dredge survey
, r
eleased in March, found that the total blue crab population jumped to 594 million crabs—60 percent above last year’s count and the highest level in seven years. Juvenile crab numbers nearly doubled, and spawning-age females rose by 29 percent, good news for watermen and crab lovers alike.
During the past year, mild winter temperatures helped boost survival rates among juvenile and adult crabs overwintering in the mud, and favorable currents pushed large numbers of larval crabs up the bay from their birthplace at the mouth of the Chesapeake. But currents and temperatures are notoriously fickle, often putting crabs on the ropes. During the winter of 2017 to 2018, for instance, a cold snap knocked out a third of overwintering adult crabs. And though the bay’s crabs are booming today, new research is showing that
climate change
and a host of other challenges will keep these fighters on their toes—with some factors giving a boost and others a lethal blow.
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Tangled history of forest fires and wildlife
By Hugh Powell/Living Bird
Photo by K. Kendall/flickr
A yellow plastic sign stapled to a skinny black tree warned ENTERING BURN: STAY ON ROADS AND TRAILS. It was a classic June day in western Montana: 50 degrees and you judge how good the weather is by how hard the rain is beating against the windshield. I was in the passenger seat of a Jeep Grand Cherokee, and Richard Hutto, a professor emeritus at the University of Montana, was leading me into the heart of the Rice Ridge Fire burn area in the foothills of the Swan mountain range.
Nine months earlier, in September 2017, this burn was the nation’s top firefighting priority during the second-most-expensive fire season on record. Rice Ridge eventually consumed 160,000 acres of forest and cost the U.S. Forest Service $49 million to fight.
“You couldn’t have asked for a better fire,” Hutto said, and as an ecologist he was serious. He drove on past the sign and into what he calls “nature’s best-kept secret,” a young burned forest.
In every direction bare trees reached up into the low gray sky, their naked branches pinwheeling off trunks as black as chainsaw oil. Yet on the ground, tiny starbursts of beargrass were already creeping out of fireproof stems, singed at the tips but otherwise brilliant green against the black soil. Off in the distance, a swath of burned trees swept down a valley and up the next slope, the red-needled edges forming huge paisleys on the green mountainside.
Birds were everywhere.
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Time to modernize the Pittman-Robertson Act
TRCP
Photo by Peter Anderson/flickr
By now, you probably know that every time you buy a hunting or fishing license and certain gear, you’re paying into a hugely successful system of conservation in America—where those of us who enjoy and take something from our natural resources also give back to fish and wildlife. You’re probably even aware of the two laws that made this happen: the Pittman-Robertson Act for hunting-related spending and the Dingell-Johnson Act for fishing-related spending.
But there’s a major difference between these policies that has become glaring as fishing participation has crept back up and hunting participation has taken a steep nosedive.
Between 2011 and 2016, the number of hunters declined by 16 percent. Hunters spend fewer days afield and less money on equipment on average than they used to. In that same time period, 2.7 million more Americans started fishing, and spending on fishing equipment increased by more than 36 percent.
This could be because about $12 million in funds created by the Dingell-Johnson Act annually go toward national efforts to recruit, retain, and reactivate anglers. Meanwhile, no such provision is made in Pittman-Robertson.
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Our world’s looming water shortage is getting closer
The New York Times
Photo by NASA/flickr
Countries that are home to one-fourth of Earth’s population face an increasingly urgent risk: The prospect of running out of water.
From India to Iran to Botswana, 17 countries around the world are currently under extremely high water stress, meaning they are using almost all the water they have, according to new World Resources Institute data.
Many are arid countries to begin with; some are squandering what water they have. Several are relying too heavily on groundwater, which instead they should be replenishing and saving for times of drought.
In those countries are several big, thirsty cities that have faced acute shortages recently, including
São Paulo
, Brazil;
Chennai
, India; and
Cape Town
, which in 2018 narrowly beat what it called Day Zero — the day when all its dams would be dry.
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To read past McGraw Reports click
here.
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