Biology Reference
In-Depth Information
gists had discovered Quagga Mussels in the Colorado River aqueduct, and
soon afterward in San Diego and Riverside counties using Colorado River
water. Quagga Mussels are a close relative of the Zebra Mussel and almost
equally feared as California invaders. Despite the state's measures, an an-
gler fishing in the San Justo reservoir near Hollister reported landing a
clump of Zebra Mussels in January 2008.
As luck would have it, this early detection of a small infestation was
easily isolated and quickly quarantined. That would not be the case for
invaders traveling down the Colorado River. If the response is rapid, en-
closed reservoirs, lagoons, and lakes can be treated to eradicate offenders.
Each target species and location may require a different approach. For the
Northern Pike, a big fish, officials detonated underwater explosions and
poisoned Frenchman Reservoir in the Sierra Nevada; for
Caulerpa taxifo-
lia
, a type of algae from the aquarium trade, a combination of hand re-
moval and bleach injections under floating tarps were needed to rid two
southern California lagoons of the pest; for Zebra Mussels in a small res-
ervoir, it was hoped that drawing the water level down and adding potash
(a common fertilizer) would do the trick.
So far, no mussels have been found in the delta or the State Water Proj-
ect, which delivers water all over California. According to Andrew Cohen,
the Zebra Mussel, a fresh water organism, needs certain calcium and pH
levels to survive—conditions that make most Sierra Nevada reservoirs in-
hospitable to the mussel, but that also might make the South Delta and
San Joaquin River more vulnerable. Every organism, super or not, has its
limits, according to Cohen.
While the Zebra Mussel could prove a big pain in water pipelines, Bay
Area residents have been feeling another kind of irritation from an exotic
invader—swimmer's itch. In recent years, kids and adults wading and
swimming on one East Bay beach have been coming home with red rashes
akin to poison oak. Scientists say the rashes are an immune response to a
parasitic Trematode Worm hosted by an exotic Japanese Snail, and they
hope to study the local outbreak.
Some exotic organisms are bad and others may be good, but most of
them change or challenge the relationships and functions of the ecosys-
tem. “We rely on these ecosystems for many different things, including
fresh water, food, sport, and commerce. We've also invested a lot of re-
search time learning how these ecosystems work so we can manage them
for our benefit. These exotic organisms come in and change ecosystems
virtually overnight, so they become completely unpredictable. These dra-
matic changes, coming one after another after another, have real costs to
human society. We can do better. We just have to decide to focus on the
problem before another 100 species colonize the bay,” says Cohen.
