To the FWGNA group:
Many of you will be familiar with the large invasive viviparid gastropods Bellamya
(or Cipangopaludina) chinensis and B. japonica.
(Biological background is available at the GSMFC, the Indiana DNR, or
the FWGSC web site.) Here in the
U.S. one commonly sees Bellamya sold as a specialty item for the
purposes of cleaning or clarifying the water in ornamental lilly ponds.
The snail has been widely introduced into the wild - our colleague Jay Cordeiro
has been monitoring their spread for several years. But the appearance of
Bellamya is not generally greeted with the same alarm that accompanies
the discovery of large ampullariid snails such as we discussed in August and September,
primarily because Bellamya does not apparently eat living
macrophytes. From a human standpoint, its introduction seems largely
benign.
Below are three little news items involving American populations of Bellamya,
the first personally collected, the second and third passed along from Jay
Cordeiro and Rick Fox, respectively. All fall under the general heading
of, "If the good Lord gives you lemons, make lemonade." Enjoy!
Bellamya Ranching in North Carolina
While on a field trip last month I was not surprised to discover large and
apparently healthy populations of B. japonica in High Rock Lake and
Tuckertown Reservoir, both impoundments of the Yadkin/Pee Dee River system in
central NC. There were previous records from Lake Hickory of the Catawba
River system next door, as well as several ponds and smaller populations
scattered around the state. I would characterize High Rock and Tuckertown
as "highly disturbed" environments, built in the 1920s by Alcoa for
hydroelectric purposes and currently supporting a lot of recreational use,
although such venues do not appeal to me personally (Photo 1).
In any case, I had just finished making collections on High Rock at a very popular
boat ramp east of Salisbury when I was approached by two state game
wardens. They had lots of questions, and once we got beyond the usual
"Who the heck are you and what the heck are you doing here?" our
conversation turned to "these large snails." They related an
interesting story.
Apparently one night in the not too distant past, their suspicions were aroused
by a large band of fishermen seining or netting on the lake under cover of
darkness. They and other officers swooped down on the nocturnal fisherman
only to discover all their nets and coolers filled with "these large
snails." The fishermen were Laotian, of Hmong descent. Since
North Carolina does not apparently have any laws regulating the harvest of
snails, the Laotian fishermen were allowed to continue.
I personally speculate that the Laotians may have previously "seeded"
Bellamya into High Rock and Tuckertown Reservoirs. This may
represent a previously unrecognized mechanism for the spread of Bellamya
in the US. Of course, very few of us approve (in principle) of
artificially spreading exotic organisms. But "snail ranching"
to feed (perhaps impoverished?) people from what is otherwise an underutilized
and already disturbed environment doesn't seem like much of a sin. If the
good Lord gives you lemons...
Bellamya Roundup in Massachusetts
Our good friend Jay Cordeiro is calling for volunteers to hand-collect Bellamya
from Johnson's Pond in Groveland, Massachusetts next Saturday, October
15. His (very cute!) PDF flier
is available for download from the FWGNA web site. Any of you in that
part of the world are encouraged to contact Ms. Susan Park before October 10
for more details.
Jay is considering a mark-recapture study aimed at estimating the current size
of the Bellamya population in Johnson's Pond, to be repeated over the
next several years, in an effort to measure the effect of his roundup
project. If he also launches a second mark-recapture survey in a nearby
pond left undisturbed, he should be able to gather data on the regulation of
population size in aquatic invertebrates of general importance. Looks
interesting!
Jay tells me he plans to "euthanize" his Bellamya
harvest. Any Laotian folks up in your part of the world, Jay? How
about "boil?"
Bellamya as a Model for Invertebrate Anatomy
My thanks (and a tip of the hat!) go to Rick Fox of Lander University up in
Greenwood, South Carolina. Rick has developed a truly impressive
investigation for his Invertebrate Zoology laboratory featuring the dissection
of Bellamya, and made his detailed notes and instructions available
through Invertebrate
Anatomy Online. The site is best viewed with MS Explorer - some of
his 19 cleanly-drafted figures don't display with Netscape.
Everybody keep in touch!
Rob
Return ... to the FWGNA home page.
