Its interesting to note the recent population increase of cormorants
in the Chesapeake Bay. The article, however, seems to be written
from an alarmist standpoint with a negative bias toward cormorants.
Key information like the content of their diet, their impact (if any)
on the entire ecosystem, their historic abundance, and some sort of
comparative basis for assessing the importance of their total fish
consumption is sadly missing. These missing important pieces make it
look like the writer is biased against cormorants, and has prejudged
them to be sinister.
When people who are ostensibly favoring protection of wildlife rush
to judge and condemn certain species, the culture of killing is
certainly reinforced. Lets face it: Cormorants are perceived by many
as ugly, messy, and annoying: they are easy scapegoats for those who
would attract funds for "control" operations. Unless they can be
shown to have specific detrimental impacts on other wildlife and its
overall diversity, it seems logical to assume they are succeeding
because they fill an available niche in the ecosystem. And if they
continue to thrive, then probably they are not causing any decrease
in their prey populations.
Guy McGrane
Millers Creek, NC (not far from SW VA)
By Bryan Watts
On 23 May, 1978, while out conducting fieldwork, Charlie Blem (avian
ecologist from Virginia Commonwealth University) discovered 6 pairs
of double-crested cormorants nesting on the James River near
Hopewell, Virginia. This was the first documented breeding of the
species within the Chesapeake Bay region. The historic event was
little noticed and there was no indication that in just over 3
decades the species would take root and become one of the dominant
fish consumers within the estuary. However, during the 2013 breeding
season, a survey conducted by The Center for Conservation Biology
documented more than 5,000 pairs breeding in 12 colonies throughout
the Chesapeake Bay. This population would be expected to consume
nearly 3000 metric tons of fish annually.
Growth in the Chesapeake Bay breeding population has been both rapid
and dramatic. As recently as 1993, a survey conducted by the Center
documented only 354 pairs. During a visit in that year to Smith
Island, Bryan Watts and Mitchell Byrd discovered 6 nests built on top
of old brown pelican nests. In 2013, this colony is the largest in
the Bay supporting nearly 2,500 pairs.
Cormorants of several species are now considered nuisances within
numerous locations across the globe. In North America, populations
were recovering from widespread shooting during the 1940s and 1950s
only to be reduced to new lows by the 1960s due to the impacts of
DDT. Since the banning of DDT, historic populations have experienced
dramatic recoveries leading to conflicts over the destruction of
habitat required by other bird species, nutrient inputs into
waterways, and fish consumption. Impacts of overwintering
populations on the aquaculture industry throughout the Southeast lead
the Fish and Wildlife Service to issue an aquaculture depredation
order for 13 southern states in 1998. Conflicts with commercial and
recreational fishing have led to the ongoing control of northern
breeding populations.
The Chesapeake Bay has always been a significant wintering site for
northern populations. For the decade prior to the discovery of
breeding there was a documented increase of cormorants using the Bay
during winter. The current size of the winter population is not
known but believed to be substantial. Northern birds that have not
reached breeding age also oversummer in the Bay in unknown numbers.
The rise of the breeding population greatly increases the fish demand
during the summer period.
Michael Wilson
Center for Conservation Biology
College of William and Mary & Virginia Commonwealth University
P.O. Box 8795
Williamsburg, VA 23187-8795
phone: 757-221-1649
fax: 757-221-1650
email: mdwils@xxxxxx
web: www.ccbbirds.org
