[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[APD] [CAPE] A little something interesting for you...
Discarded aquarium plants blamed for fish kill
The Associated Press
Wilmington- A Brunswick County fish kill might have been caused by a
seaweed-like aquarium plant that people have dumped into waterways over the
years, say state environmental officials. At first, investigators looked
for waste discharges from a farm or septic tank, but none were found. They
couldn’t trace it to pesticides or herbicides spilled in the water.
“We were scratching our heads wondering what was going on,” said Rick
Shiver, head of the N.C. division of Water Quality’s Wilmington regional
office. Further investigation into the cause of the fish kill has officials
leaning toward blaming a nonnative seaweed-like plant that is lining
increasing areas of the Town Creek watershed.
Brazilian elodea, a popular aquarium plant native to South America that’s
also known as egeria, was probably introduced into the country’s waterways
by people disposing of aquarium contents into rivers and ponds. “They
probably just got turned loose and spread around that way,” said Randy
Westbrook, national invasive plant coordinator with the U.S. Geological
Today, the hydrilla-like plant, which grows either rooted to the bottom or
free-floating, is relatively common in North Carolina and is quickly
becoming a major nuisance. Shiver said it appears that a large amount of
the sun-loving elodea died and began decomposing in the blackwater creeks.
Since decomposition requires oxygen, the plants robbed the waterway of its
dissolved oxygen and kill fish.
Shiver said water tests where dead fish were found showed dissolved oxygen
was about 10 percent of normal levels. “What we’re seeing is a direct
correlation between the elodea and dissolved oxygen,” he said. “Where we
find the elodea, we find low dissolved oxygen levels.”
Bill Adams, chief of the Army Corps of Engineers’ environmental resources
section in Wilmington, has been monitoring Town Creek for several years. He
said he doesn’t know what could have caused the elodea to die off, but it
could just be a natural of there being so much of the weed. Adams said some
tributaries are choked with the weed.
Larry Cahoon, a marine biologist at UNC-Wilmington, said he would guess that
the aquatic weed’s growth it tied to a rise in nutrients in the watershed.
“This is a pattern we’ve seen elsewhere,” he said. “Now the question is
where are the nutrients coming from.”
As the elodea population has increased, the number of native shoreline and
marine plants has decreased. “It’s a plant that can overwhelm a system.”
Adams said, noting that the river’s once ecologically diverse shoreline is
now in places just wavy stands of elodea that can block sunlight and
interfere with navigation.
Shiver and Water Quality has implemented a monthly monitoring program to see
if low oxygen levels in the creek was a one-time event.
The new MSN 8: smart spam protection and 2 months FREE*