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> \<steve_minkkinen@fws.gov\>
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> Subject
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> Re: Fw: northern snakehead parasites

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Dear Mr. Minkkinen,

Thanks for your message. Concerning the nematodes from nothern
snakeheads on your photos: I can only confirm the information by Mark
Grygier. The nematodes are larvae of the genus Eustrongylides; adults of
these species are parasites of the digestive tract of various
fish-eating birds (e.g. cormorants). At present, only three,
morphologically very similar species of Eustrongylides are recognized,
two of them occur both in palaearctic Eurasia and North America; their
larvae are indistinguishable. In some localities, larvae of
Eustrongylides occur in large numbers in fish, amphibians and reptiles.
In my opinion, the Eustrongylides larvae in snakeheads in the USA belong
to one or more indigenous (not introduced) species and, undoubtedly,
occur as well in other cold-blooded hosts there. In addition to
parasites of snakeheads mentioned by Mark Grygier, i.e., the nematode
Pingus sinensis and the copepode Lamproglena chinensis, also some other
helminth parasites (trematodes, cestodes) occur in this host. For
example, a specific parasite of this fish in East Asia is the
dracunculoid nematode Clavinema fujimotoi, whose large-sized, viviparous
females are found in the fins of this fish during late spring and early
summer.

With best regards,

Frank Moravec

Dr. František Moravec, D.Sc.

Institute of Parasitology,

Academy of Sciences of the Czech Republic,

Branišovská

\>\>\> \<steve_minkkinen@fws.gov\> 26.1.2006 15:34 \>\>\>

I was referred to you by Mark Gryier. I am coordinating the development
of

a national snakehead control and management plan for the United States
Fish

and Wildlife Service. You may be aware that northern snakeheads have bee

introduced into the Potomac River near Washington D.C. I have also been

conducting research into the biology and behavior of snakeheads. We have

been finding nematode parasites in snakeheads and I am interested in

determining if the parasite is a native species or if they could be a

Chinese species (pingus sinensis). I am attaching some pictures of the

parasites. From what I understand we would need the adult parasite from
a

bird in order to have them identified. I would appreciate any advice you

could provide.

(See attached file: snakehead_anterior.jpg)(See attached file:

snakehead_gross.jpg)(See attached file: P1050119.JPG)(See attached file:

DSCN0074.JPG)

Steve Minkkinen

Project Leader

Maryland Fishery Resources Office

\-\-\-\-- Forwarded by Steve Minkkinen/CBFO/R5/FWS/DOI on 01/26/2006
08:48 AM

\-\-\-\--

Grygier

MarkJoseph

\<grygier@lbm.go.j To

p\> steve_minkkinen@fws.gov

cc

01/25/2006 07:59 nakai@lbm.go.jp,

PM John.Odenkirk@dgif.virginia.gov

Subject

Re: northern snakehead parasites

Dear Dr. Mikkinen:

\>We have been finding a high prevalence of nematode parasites in the

\>snakeheads. I am attaching some pictures we have taken. Do you know if

\>there is a way for us to identify if this parasite is a native one
from

\>prey consumed in the river or if they are a introduced species from
China?

The nematodes in your photos are encysted larvae of the family

Dioctophymatidae, presumably of the genus Eustrongylides, which infest

fish-eating birds as adults. The species can only be confirmed by
feeding

the larvae to, for example, ducks for later dissection to obtain the

adults. I think this sort of worm has a worldwide distribution and is

unlikely to have been introduced to your area along with the fish. It is

not host-specific; in Lake Biwa we have such
dioctophymatid/Eustrongylides

larvae from 9 species of fish so far, including small fish, large fish,

native fish, and introduced fish (bluegill, largemouth bass and northern

snakehead). For an introduction to the history of study and literature
of

Eustrongylides in North America, please see p. 267 in G. L. Hoffmann\'s

book, \"Parasites of North American Freshwater Fishes\"; there is also a

poor photo there (Fig. 479 on p. 334).

My tentative identification from your photos is based only my

experience at Lake Biwa; I am not a trained nematologist. For a more

learned opinion, please send the same e-mail with attached photos to Dr.

Frank Moravec, the world\'s premier nematologist of freshwater fishes,
who

was a member of the Lake Biwa aquatic parasite survey I led: e-mail

\<moravec@paru.cas.cz\>. Regarding Eustrongylides, please see his book
as

well: \"Parasitic Nematodes of Freshwater Fishes of Europe\".

The nematode you should be looking for in northern snakehead is

Pingus sinensis (family Quimperidae), which lives in the caeca that are

attached laterally to the gut just posterior to the stomach. You should

perhaps also be looking for the lernaeid copepod Lamproglena chinensis

attached to the gills. These are the two putatively introduced parasites

of northern snakehead in Lake Biwa. If you like, I can send you my

Japanese-language publication concerning the introduced parasites of
Lake

Biwa, which includes small photos of both of these species. These are
both

specific to snakeheads, as far as I know.

If you need more background on the other species of Asian

snakeheads, I can send you a photocopy of the following paper, which is

in English:

Ng, P.K.L. & Lin, K.K.P. 1990. Snakeheads (Pisces: Channidae): natural

history, biology and economic importance. Pp. 127-152 in: Ming, C..L. %

Ng, P.K.L. (eds.), Essays in Zoology. Papers Commenorating the 40th

Anniversary of the Department of Zoology, National University of

Singapore. Department of Zoology, National University of Singapore,

Singapore. Or you can write directly to Peter Ng, who is a prolific

taxonomist of crabs, as well as a fish worker, for a reprint:

\<dbsngkl@nus.edu.sg \>.

Sincerely, Mark J. Grygier, Ph.D. General Research Scientist,

Curator of Misc. Invertebrates, and Museum Studies Research Group Leader

Lake Biwa Museum, Oroshimo