Page 28 - aruba-today-20180922

A28 SCIENCE
Saturday 22 September 2018

Canadian crabs with bad attitude threaten coastal ecosystem

By DAVID SHARP hybrid vigor is in play, he
Associated Press said. The hybrid vigor theory
BIDDEFORD, Maine (AP) suggests that crabs could
— Canadians are known be more aggressive as they
as friendly folks, but these establish themselves, but
crabby brutes migrating will mellow out later.
from Canadian waters are The quarrelsome newcom-
better suited for the hockey ers currently comprise only
rink. about 2 to 3 percent of
Green crabs from Nova green crabs crawling on
Scotia are the same spe- the ocean floor off Maine,
cies as their cousins that but those numbers are cer-
already inhabit Maine wa- tain to grow, Frederich said.
ters, but are ornerier and “It will be an entirely differ-
angrier, threatening to ac- ent ball game,” he predict-
celerate harm to the coast- ed.
al ecosystem by gobbling “It’s just a question of when
up soft-shell clams and de- more of the crabs come
stroying native eel grass, a This June 6, 2018, file photo shows a green crab in Portland, Maine. A University of New England and out-compete the
researcher said. researcher said green crabs migrating from Nova Scotia are ornerier and angrier than their Gulf Maine green crabs.”
The docile green crabs of Maine cousins. The docile green crabs
shrink from a threat, while Associated Press have been around for
the newcomers are more Green crabs, even the The crabs were in no mood crabs on a bed of eel grass more than a century in
apt to wave their pincers docile ones, are consid- for games.At a distance in a saltwater pool, and the New England waters, but
and charge. ered a scourge that can of 5 feet, the pint-sized difference was stark. they’ve emerged as a ma-
“What we’re seeing is this devour soft-shell and juve- brutes, which measure 4 to The Canadian invaders jor problem as the Gulf of
insane level of aggressive- nile clams. 5 inches across, assumed a shredded the eel grass like Maine has warmed.
ness,” said Markus Fred- They can destroy eelgrass fighting posture. Those that Edward Scissorhands in The feistier crabs arrived off
erich, a professor at the that provides a hiding grabbed him were in no their efforts to scarf down Nova Scotia in the 1980s,
University of New England. place for juvenile sea crea- hurry to let go. marine organisms seeking and currents brought their
They’re each genetically tures. “Any time I went down refuge, Frederich said. larvae southward into New
distinct. But the Canadian crabs to grab one they went to The first round of study fo- England waters.
The new crab variant take it to a new level. grab me instead,” he wrote cused on 200 crabs from Eventually, the newcom-
that originated in north- Louis Logan, a University of in an email. Canada, and will be pub- ers will move farther south-
ern Europe is hardier and New England graduate stu- One of them, in particular, lished in coming months. ward. “We can’t do any-
adapted to colder water dent, had the unpleasant would jump out of the wa- Further studies will focus on thing about it,” he said.
than the more docile crab, task of labeling the crabs ter in its frenzy to attack. whether a specific gene “The only thing that we can
which originally came from captured from Nova Scotia In the lab, researchers plays a role in the aggres- do is learn how to live with
southern Europe. waters for the research. unleashed both types of siveness or if a factor called it.”q

Japan space rovers lowered

to asteroid to collect data

By MARI YAMAGUCHI as close as 55 meters (180 feet) at a time because the
Associated Press feet) to the asteroid to low- extremely weak gravity on
TOKYO (AP) — A Japanese er the rovers, waited for a the asteroid makes rolling
spacecraft released two minute and then rose back difficult. They can continue
small rovers on an asteroid to its waiting position about jumping as long as their so-
This computer graphic image provided by the Japan Aerospace on Friday in a mission that 20 kilometers (12 miles) lar panels and power last,
Exploration Agency (JAXA) shows two drum-shaped and could provide clues to the above the surface. JAXA JAXA said.
solar-powered Minerva-II-1 rovers on an asteroid. Japanese origin of the solar system. said the release went suc- Friday’s release bolstered
unmanned spacecraft Hayabusa2 released two small Minerva-
II-1 rovers on the asteroid Ryugu on Friday, Sept. 21, 2018, in a The Japan Space Explo- cessfully. the project members’ con-
research effort that may provide clues to the origin of the solar ration Agency said the “We are very hopeful,” fidence ahead of more dif-
system. JAXA said confirmation of the rovers’ touchdown has to two Minerva-II-1 rovers project manager Yuichi ficult maneuvers in the fu-
wait until it receives data from them on Saturday. were lowered from the un- Tsuda said. “I’m excited ture, Tsuda said.
Associated Press manned spacecraft Haya- about seeing the pictures. I Hayabusa2 is scheduled to
busa2 to the asteroid Ryu- want to see the scenery of attempt three brief touch-
gu. The spacecraft arrived space seen from Ryugu’s and-go landings on the
near the asteroid, about surface.” asteroid to collect samples
280 million kilometers (170 The two rovers, each about in hopes of providing clues
million miles) from Earth, in the size of a cookie can, to the origin of the solar sys-
June. are to capture images of tem and life on Earth. Since
JAXA said confirmation the asteroid and measure it arrived at Ryugu, scien-
of the robots’ safe touch- surface temperatures be- tists have been looking for
down has to wait until it re- fore a larger rover and a suitable landing sites on
ceives data from them on lander are released later. the uneven surface, and its
Saturday. The rovers move by “hop- first attempt is expected in
Hayabusa2 approached ping” up to 15 meters (50 October.q