CRD 01-17
Session
IX: Atlantic Salmon
| Infectious
salmon anemia in Maine-cultured Atlantic salmon |
Session
IX: Atlantic Salmon
Abstract No. IX-1
ORAL PRESENTATION |
Presentation
Sharon A. MacLean
NOAA/NMFSNEFSC, 28 Tarzwell Dr., Narragansett, RI 02882-1152
Infectious salmon anemia
is a viral disease of Atlantic salmon, principally those in culture
environments. The disease was first reported in Norway in 1984 and
subsequently has been reported from Scotland, Faroe Islands, Canada,
and the US. Genetic sequencing indicates two strains of virus: the
Norwegian/Scottish strain and the North American strain. As indicated
by its name, the disease is characterized by internal hemorrhaging
resulting in severe anemia. Mortality rates typically are 50%. Currently
more than 50% of the culture sites in Maine’s Cobscook Bay are diseased
and fish health management plans are being implemented to limit the
spread of the disease to other areas in Maine. There is concern for
the potential impact of this virus on Atlantic salmon restoration efforts
and on this endangered species. The presentation will discuss efforts
to control this disease, vaccine development, bay-area management,
coordinated US-Canada fish health management plans, research planned,
and impacts on the Atlantic salmon restoration project.
| Smolt
production dynamics in endangered Atlantic salmon populations |
Session
IX: Atlantic Salmon
Abstract No. IX-2
ORAL PRESENTATION |
Presentation
John F.
Kocik1, Timothy F. Sheehan2, Kenneth F. Beland3,
and Jennifer FitzGerald2
1National Marine Fisheries Service, 31 Main St., Orono, ME 04473
2 NOAA/NMFS/NEFSC, 166 Water St., Woods Hole, MA 02543-1026
3Maine Atlantic Salmon Commission, 650 State St., Bangor, ME 04401-5654
US Atlantic salmon populations
with a substantial naturally reproducing component are restricted to
eight rivers in eastern Maine, listed as endangered. Adult assessments
conducted since 1992 have indicated that abundance has declined and
remains low. To identify causes for this decline, we initiated a program
to quantify smolt production in the Narraguagus River and index production
in the Pleasant and Sheepscot Rivers. In the Narraguagus and Pleasant
Rivers, we conducted annual geographically-stratified basinwide estimates
of large parr (>130 mm) abundance using electrofishing in late summer. From
April until June, we monitored the emigration of Atlantic salmon smolts
in all three rivers using rotary screw fish traps. In the Narraguagus
River, parr estimates have ranged from 11,700 to 27,000 and corresponding
emigrating smolt estimates ranged from 1,800 to 3,600. Even in years
with substantial increases in large parr production (126%), smolt production
has increased only modestly (3%) in the Narraguagus. In the Pleasant
and Sheepscot Rivers, the smolt population has numbered less than 1,000. Our
studies have also identified smolts in the Pleasant River that are
of commercial aquaculture origin, confirming a fish-management concern. Total
smolt production in these watersheds is well below the estimated production
capacity of 300/ha and warrants continued study to determine mechanisms
responsible for low production.
Keywords: salmon,
endangered, smolt
| Characterizing
rearing history of Pleasant River smolts using scale image analysis |
Session
IX: Atlantic Salmon
Abstract No. IX-3
ORAL PRESENTATION |
Presentation
Ruth E. Haas-Castro, John
F. Kocik, and Christopher M. Legault
NOAA/NMFS/NEFSC,
166 Water St., Woods Hole, MA 02543-1026
Atlantic salmon in eight
Maine rivers were listed in November 2000 as endangered under the Endangered
Species Act. The Northeast Fisheries Science Center has monitored smolt
production in Maine rivers from 1996 onwards. Atlantic salmon in the
Pleasant River constitutes one of the eight remnant populations now
protected under the Act. To monitor smolt production in this river,
we deployed a rotary screw trap during early April-June in 1999, 2000,
and 2001 at Columbia Falls. Scale samples were collected from 382 of
617 smolts captured in 1999 and 120 of 160 smolts caught in 2000. Tissue
samples were also collected from a portion of the fish for genetic
analysis. Although most smolts in both years were of wild origin, many
of these fish exhibited fin deformities, coloration, and body form
that suggested they were of hatchery origin. We therefore attempted
to determine the feasibility of using scale characteristics to differentiate
smolts into three categories: wild origin, early escaped hatchery origin,
and hatchery origin. Our results will be important in determining
the magnitude of hatchery origin and hatchery escaped fish in the Pleasant
River, and in evaluating the efficacy of actions that have been taken
to enhance the survival of wild fish.
|
Stock
specific measures of marine growth for
three remnant populations of Atlantic salmon, Salmo salar,
from eastern Maine |
Session
IX: Atlantic Salmon
Abstract No. IX-4
ORAL PRESENTATION |
Presentation
Timothy
F. Sheehan1, John F. Kocik2 and Ernest Atkinson3
1NOAA/NMFS/NEFSC, 166 Water St., Woods Hole, MA 02543-1026
2NOAA/NMFS/NEFSC, 31 Main St., Orono, ME 04473
3Maine Atlantic Salmon Commission, P.O. Box 457, Rte. 1, Campbell's
Hill Rd., Cherryfield, ME 04622
We
monitored stock-specific marine growth rates for two years from three
Atlantic salmon populations in eastern Maine. Individuals were spawned
at a federal hatchery and reared to smolt stage at commercial facilities. Approximately
1,000 individuals from each stock were transferred to two marine sites
for two sea-winters of marine grow-out. We tagged each individual
with an elastomer injection to allow for stock differentiation. Individuals
at each site were reared in a single sea-cage and experienced similar
environmental influences and growing conditions. Biological sampling
occurred approximately every other month. Standardized photographs
were taken of a random sample of individuals after two years of grow-out,
and Truss Analysis (multivariate morphometrics) was conducted on the
photographs. We tested for stock-specific differences in growth with
univariate and multi-variate techniques. Significant differences in
growth were evident at each site. Significant differences in growth,
between populations reared within a common environment, indicate that
these populations do harbor some genetic uniqueness. This information
maybe useful in understanding the ecological implications of subtle
genetic differences and may help managers better understand the dynamics
of these stocks while developing conservation plans.
| Origin
and distribution of Atlantic salmon post-smolts in Penobscot
Bay, ME |
Session
IX: Atlantic Salmon
Abstract No. IX-5
ORAL PRESENTATION |
Presentation
Craig A. Tinus and Russell
W. Brown
NOAA/NMFS/NEFSC,
166 Water St., Woods Hole, MA 02543-1026
The fate of out migrating
post-smolt Atlantic salmon is poorly understood because monitoring
is extremely difficult once they have left the rivers and entered the
marine environment. Over a two year period, the NEFSC Atlantic salmon
task has developed a coordinated research program focused on hatchery
and naturally reared Atlantic salmon smolts in the Penobscot watershed,
which is the largest remaining population of wild Atlantic salmon in
the United States. This coordinated program involves the marking and
release of 170,000 –180,000 hatchery smolts, a rotary screw trap monitoring
program at the head of tide, and an estuary and near shore marine trap
survey program. In May, 2000 the NOAA- fisheries Atlantic salmon working
group implemented a pair trawl sampling approach to the capture and
live release of post-smolts based on technology originated by investigators
in Norway and Canada. We pair trawled a modified mid-water trawl with
an aluminum catch box at the cod end throughout Penobscot Bay and near
shore waters of the Gulf of Maine. Our total catch was 1458 Atlantic
salmon post-smolts with a handling mortality of 7.9%. Of those fish,
608 scale samples were taken and preliminary analysis suggests that
3.2% were naturally reared. Besides length, weight and condition we
took 87 blood and 139 gill samples for analysis of smolt physiology. These
data complete a physiology data series of marked hatchery reared pre-smolts
that will yield a far better understanding of smolt physiology in a
natural system. Ninety-nine stomachs were removed from mortalities
and analyzed for contents. Those data suggest that post-smolts shift
from feeding on riverine drift to being opportunistic piscivours soon
after entering the marine system. Recovery of 355 elastomere marked
fish will allow for evaluation of the relative contribution of different
hatchery release groups to the post-smolt population. A rough understanding
of migration routes was gained by catch data. A follow-up cruise in
Spring 2002 will expand the spatial and temporal scale of sampling
to further explore trends in near shore marine distribution. This
sampling technique has demonstrated considerable potential for evaluating
post-smolt biology at a critical life history stage.
