[BCNnet] Scaup decline and zebra mussels

[Heaton.Duane@epamail.epa.gov]

BCNnet:

I've pasted this from a listaserv of daily news clips from around the
Great Lakes. This appeared in the Erie Times-News today, Friday, Sept.
20.  If interested in Great Lakes Daily News, see
http://www.great-lakes.net/news/  From the names of some of the species
(e.g., Buffalo head and scooters), John Bartlett is obviously not a
birder.

Duane Heaton
Palatine, IL

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Duck population declines


                       By John Bartlett
                       john.bartlett@timesnews.com

                       Zebra mussels could be contributing
                       to a drastic continent-wide decline in
                       scaups, two species of ducks
                       commonly found along Lake Erie's
                       shoreline, according to Canadian
                       researchers.

                       Scaups have been eating zebra
                       mussels, and researchers believe a
                       high concentration of selenium in the
                       mussels' bodies have hurt the ducks'
                       ability to reproduce.

                       Zebra mussels, which filter the water, draw in
selenium contained in lake water.
                       The selenium accumulates in the mussels' body
tissue.

                       Scaups ingest the zebra mussels and basically
overdose on the selenium,
                       crippling their reproductive ability, said Scott
Petrie, research director of
                       Canada's Long Point Waterfowl and Wetlands
Research Fund.

                       "It seems like the obvious answer (to the decline
in scaup populations), but we
                       don't have all the data yet," Petrie said.
"However, I would be surprised if this isn't
                       the cause."

                       Selenium is released into the Great Lakes from
both natural and industrial
                       sources.

                       The fund's research has shown high levels of
selenium in scaups, and the decline
                       in the species corresponds to the explosion of
zebra mussels in the Great
                       Lakes, he said.

                       The zebra mussel is believed to have entered the
Great Lakes in 1986, when a
                       foreign ship dumped its ballast water. With no
natural enemies and suitable
                       habitat, zebra mussel populations soared and
scaups began to feed heavily on
                       them, Petrie said.

                       The current breeding population of greater and
lesser scaups, the two species, is
                       34 percent below the long-term average, said
Kevin Jacobs, northwest regional
                       waterfowl biologist for the Pennsylvania Game
Commission.

                       "The breeding population of greater and lesser
scaups combined is estimated at
                       3.5 million, so it is still an abundant species
compared to many," Jacobs said.
                       "However, its long-term average population is 5.3
million. One of the alarming
                       facts is its decline has been especially steep in
recent years."

                       The decline in scaups has drawn the attention of
wildlife managers and
                       researchers across North America. In response to
the decline, the daily hunters'
                       bag limit for scaups was cut in half to three
birds, he said. The duck-hunting
                       season for Presque Isle State Park and along the
Lake Erie shoreline in
                       Pennsylvania is from Oct. 28 through Nov. 16 and
from Nov. 25 through Dec. 7.

                       "They are an important species in Lake Erie and
along the Presque Isle
                       shoreline," Jacobs said.

                       The heavy concentration of selenium found in
scaups, their ensuing population
                       decline and the apparent link to zebra mussels
raises concerns for many
                       species and the integrity of the Great Lakes
ecosystem, Petrie said.

                       "I'm concerned about a number of waterfowl
species - the Buffalo head,
                       golden eyes, scooters, long-tailed ducks and old
squaw - but certainly
                       other species could be affected," Petrie said.

                       And selenium is not the only chemical of concern.

                       Zebra mussels could be concentrating a wide
variety of toxins and passing them
                       on to animals further up the food chain.