|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||
|
|
||||||||||
|
|
|
|||||||||
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|||||||
|
|
||||||||||
|
Vertical
Transmission Of Flavobacterium
psychrophilum And Its Impact Within Atlantic Salmon Restoration Rocco C. Cipriano
U.S. Geological Survey, National Fish Health Research
Laboratory, 1700 Leetown Road, Kearneysville, WV 25430 Federal
restoration of Atlantic salmon in the northeastern United States concentrates
principally upon enhancement of stocks within the Connecticut River, Merrimack
River, Penobscot River and several
smaller rivers on the Downeast coast of Maine.
River-specific brood stocks are used
to enhance the genetic integrity of the fish within each river
system. Consequently, the gametes
produced from the limited number of adult salmon returning to each of these
river systems are extremely valuable in terms of providing a sufficient number
of offspring to continue the restoration effort. In the course of study, chronic symptoms of Bacterial Coldwater Disease,
caused by Flavobacterium psychrophilum, were noted among a proportion of offspring
that are propagated and stocked as smolts.
Classical peduncle lesions and chronic mortality were associated with
the affected fish. The disease was
more pronounced in salmon reared
in two-year rather than one-year smolt production cycles. Following the identification of these
symptoms, the pathogen was shown to be the etiologic agent of mortality among
yolk-sac fry in Heath incubators, associated
with reductions in egg
viability, and indicated to be transmitted by intra-ovum infection. Subsequently, vertical transmission of F. psychrophilum was shown to be widespread throughout the range
encompassed by the restoration program.
The pathogen, therefore, has a significant role in the production of
quality gametes and may be an extremely
important factor in the post-stocking survival of salmon fry and
smolts. Return to 25th Annual Eastern Fish Health WorkshopReturn to Leetown Science Center Home Page |