Kelt Tracking
The
MSA and Atlantic Salmon Federation in cooperation with the Department of Fisheries and Oceans is conducting a program to monitor
kelts as they exit the river in spring and as they return back to the ocean. The kelts are captured by angling and a transmitter is surgically inserted
into the abdominal cavity. This transmitter gives each fish an individual code, which allows us to identify
it when it passes by receivers located at the head of tide, in the estuary, outer Miramichi Bay or through the Strait of Belle
Isle.
We are very excited about this program. This information will help us understand the migration paths of kelts, the temperature and depths kelts prefer to migrate
through how long
individual kelts spend it the ocean and possible sources of mortality for kelts. Click on the link to view more about
this exciting program.
Kelt Tracking 2008-2011 (click here)
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| Electrofishing Barrack's Brook on the Sevogle for the presence of juvenile salmon |
Juvenile Assessment - Electrofishing
The Miramichi Salmon Association (MSA) conducts an
electro-fishing program each year to assess the distribution of juvenile Atlantic salmon in the headwater areas of the Miramichi
River watershed, which may not be easily accessible to spawning adults. In low water years adult salmon
may not be able to access headwater spawning areas or may be impeded by beaver dams. This limits the number
of adults successfully migrating upstream and subsequently reduces the number of fry at these sites. Once
these priority areas are identified they are stocked with Atlantic salmon fry raised at the Miramichi Salmon Conservation
Centre or through the satellite rearing program. All of the salmon fry that are stocked into these areas
are marked by removing the adipose fin. Electrofishing areas that were stocked the previous year allow
us to evaluate the success or failure of past stocking activities by identifying and recording any adipose clipped parr found
at the site. In many cases areas which have been stocked in the past few years will show a presence of
adipose clipped parr identifying that area as a successful stocking site.
The MSA also works co-operatively
with the Department of Fisheries and Oceans (DFO) Science Branch on another survey to target sites being monitored on a yearly
basis to assess juvenile Atlantic salmon populations on the Miramichi watershed over time. The survey targets
sites with good quality juvenile salmon habitat in the lower reaches of the Miramichi watershed. This survey
allows us to compare the numbers of fry and parr from year to year, determine survival from each juvenile stage and determine
if different tributaries are meeting the production targets.
The electrofishing program has been financially supported
by the NB Wildlife Trust Fund for many years.
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| Electrofishing a DFO closed site on the Cains River |
Smolt Study on the Northwest
Miramichi - 2011
In 2011 the Miramichi Salmon Association decided
to switch the smolt project over to the Northwest Miramichi because of concerns that not enough adult salmon were returning
to the Northwest Miramichi River each year to meet the conservation requirement to sustain Atlantic salmon. The
Northwest Miramichi likely experiences an increased harvest compared to the Southwest Miramichi of grilse and salmon due to
the abundance of public pools, crown reserve stretches and First Nation Fisheries Allocations which could reduce the number
of salmon available for spawning each year. Additionally the Northwest Miramichi has an increasing striped
bass population which likely contributes to increased mortality of smolts exiting the Northwest system on their way to the
ocean.
Electrofishing
studies on the Northwest Miramichi have consistently indicated an abundance of juvenile salmon (fry and parr) in the river,
the adult returns have been much lower than should logically be expected. It has been assumed that smolt
(young salmon ready to migrate to the ocean) production would be consistent with the levels of juveniles, however adult returns
to the Northwest Miramichi do not seem to reflect this trend. The individual smolt estimates will also
allow us to determine which tributaries contribute the most to smolt production on the Northwest Miramichi since the juvenile
densities vary between tributaries, with the Little Southwest being the lowest, Sevogle moderate and Northwest Miramichi the
highest.
An accurate estimation of the total smolt population
migrating from the Northwest Miramichi River and its tributaries is an essential component to understanding and managing Atlantic
salmon in this watershed.
On the Sevogle, Northwest and Little Southwest Rivers smolt
wheels were used to capture smolts for tagging in May when they migrated downstream to the ocean. The
smolt wheel was strung across the river by an overhead cable and floated on the top of the water by two large pontoons. Any
fish that entered the trap were guided into the trap’s holding box which is located at the back of the smolt wheel.
Each fish species that was caught was identified, counted and released, except for salmon smolts, which were
measured for fork length and then tagged with streamer research tags. After the smolts were tagged
they were moved upstream of the smolt wheel. The percent of tagged smolts that are recaptured at the smolt
wheel allow us to estimate the number of smolts moving out of each river.
A large trapnet was installed in the estuary of the Northwest
Miramichi at Cassilis to capture smolts moving from freshwater into the estuary. Tagged smolts captured at the Cassilis
trap net allow us to get an estimate of the smolts moving out of the entire Northwest Miramichi system. The
percent of tagged smolts from the Little Southwest, Sevogle and Northwest Miramichi that are recaptured at the trapnet allow
us to estimate the number of smolts moving out of the Northwest Miramichi River system.
Click here to see a working smolt wheel
Click here to see inside of the smolt wheel live box
Smolt Production Study 2002-2010
The Miramichi River is one of the last great salmon rivers
that supports large returns of Atlantic salmon and offers the opportunity for public and private fishing. During the late
1980’s and early 1990’s, management actions to reduce the harvest of large female spawners in the commercial and
sport fishing sectors had resulted in the river exceeding its spawning requirements. However, the Miramichi has not exceeded
spawning thresholds for Atlantic salmon since 1996. The population of adult salmon has been stable for the past 10 years,
however, returns to the Miramichi are less than should be expected, especially given the high juvenile salmon abundance
in the river. Although it is known that the present returns of Atlantic salmon from the ocean are lower than in the previous
decade, the Miramichi, as one of the largest runs of Atlantic salmon in North America, should be monitoring it's smolt
run. Thus, there is a need to know more about the numbers of smolt going to sea and also about any changes which may be taking
place in the physical condition of smolts due to such factors as temperatures in all seasons, water levels, pollution or possibly
even an over-abundance of juveniles competing for space in the river habitat.
On the Miramichi, 2 to 3
year old juvenile salmon that are greater than 10 cm undergo a physiological transformation in spring to prepare them for
life in saltwater, this stage is termed a smolt. These smolts leave the river and migrate towards the ocean
during May and June of each year. An accurate estimation of the total smolt population migrating from the
Miramichi River is an essential component to understanding and managing Atlantic salmon in this watershed. By
estimating the number of smolts that leave the Miramichi watershed each year we can calculate the marine survival as they
return as grilse or two sea-winter salmon. The MSA works cooperatively with the Department of Fisheries and Oceans and International
Paper to conduct smolt estimates each year and some financial assistance is obtained from the NB Wildlife Trust Fund.
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| Rotary screw trap on the Cains River |
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| Trap net used to catch smolts migrating downstream |
The
smolt estimates are derived from a mark recapture experiment. Rotary screw traps are set up on three tributaries,
the Cains, Dungarvon and Rocky Brook which are used to capture and smolts for tagging. All the fish in
the live-box are collected and sorted. Each species is identified, counted and released, except for salmon
smolts, which were measured for fork length and then tagged with streamer research tags. Scale samples
are also taken on a percentage of the fish for age analysis. After the smolts are tagged they are moved
upstream of the smolt wheel. The percent of tagged smolts that are recaptured at the smolt wheel allow
us to estimate the number of smolts moving out of that particular tributary (Cains, Dungarvon or Rocky Brook).
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| Sorting smolts at the trap |
A single large
trapnet is installed each year in the estuary of the Southwest Miramichi at Millerton to capture smolts moving from freshwater
into the estuary. Tagged smolts captured at the Millerton trap net allow us to get an estimate of the smolts moving out of
the Southwest Miramichi. The trapnet efficiency is calculated by the percentage of the smolts tagged in
the tributaries being recaptured. The smolt estimate is based on the number of smolts that were marked
in the tributaries, the number of tagged smolts that are recaptured at the estuary trap net, and the total number of smolts
captured at the estuary trap net. The trap net is fished daily, and the smolts are sorted from the rest
of the species captured. Each day, sub-samples of up to 100 smolts are measured and 20 are sampled in detail
for length, weight, sex and age. All smolts captured are counted and checked for adipose fin clips and
streamer tags and then released.
Smolt production on
the Southwest Miramichi is good, reaching the targets for smolt production in 4 of the last 5 years (not including 2005 due
to wash out). Smolt production on the Southwest Miramichi has ranged from 500,000 – 1,470,000 fish
between 2001-2009. The Cains River produces between 38,500-98,000 smolts per year and the Dungarvon River
typically produces between 22,000 – 84,000 smolts per year. This research has indicated that at-sea
survival is much lower than it was a few decades ago and that something in the ocean is influencing the returns of adult salmon
back to the river.
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| Tagging smolts with streamer tags |
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| Clear streamer tag |
Adult Assessment
The current adult assessment for Atlantic salmon on the
Miramichi River is based on a mark recapture experiment coordinated by DFO. Adult salmon are tagged at
traps with a Carlin tag when they enter freshwater, are released and a proportion are recaptured further upstream.
In years when large numbers of tags are applied there is more confidence in the estimates, however in years when less
tags are applied and there is less reliability in the numbers. Typically the assessment is adequate for
the Miramichi River as a whole, but when the assessment is broken down into two different rivers, the Northwest and Southwest
Miramichi, there is less reliability in the estimates. Additionally some of the salmon mix between the
two branches, making things even more complicated. It is important to have separate estimates for the Northwest
and Southwest Miramichi because there are likely different harvest rates on these systems and we want to ensure the sustainability
of both branches into the future.
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| The divers get ready to seine the pool |
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| Tyler checks a grilse for tags and clips |
In order to attempt
to improve the stock assessment, we collaborated with DFO to initiate the adult seining program, which worked in conjunction
with the MSCC’s broodstock collection program. Seining is a good method because many different tributaries
on the Miramichi can be sampled (more coverage), it allows tagged fish to be recaptured, and captures a number of unmarked
fish, which is required in order to achieve the estimate. Additionally it reduces the exchange of fish
moving from the Northwest to the Southwest because fish are recaptured higher in the system. Adult salmon
passing through the DFO index traps are tagged with Carlin tags and received an adipose punch. Therefore
if an angler removed a tag we would be able to account for the tag loss. Pools are seined by surrounding
the pool with a small meshed net which surrounds the fish in the pool. The net is pulled into shore and
all the fish are checked for tags and punches, counted and released.
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| Mark checks a male salmon |
In
2008, seining pools was made very difficult by the very high water that summer and fall. Due to the high
rainfall many fish that would typically hold lower in the river system made their way upstream earlier. This
meant that fewer fish held in some of the pools that typically held large numbers of fish. In total we
seined 14 pools, 4 on the Northwest Miramichi and 10 on the Southwest Miramichi, with some pools being seined multiple times.
In total we were able to capture 351 grilse and 104 salmon on the Northwest Miramichi and 542 grilse and 257 salmon
on the Southwest Miramichi. Included in those numbers we captured 4 marked grilse on the Northwest Miramichi,
and 6 grilse and 1 salmon on the Southwest Miramichi that were tagged and/or punched. In 2009, seining was much easier because
of low water conditions throughout much of the late summer and early fall. Unlike 2008, most of the fish
held in pools lower down so we were able to capture large numbers of fish and seine larger pools than we were able to seine
in 2008. In total we seined 14 pools, 6 on the Northwest Miramichi and 8 on the Southwest Miramichi, with
some pools being seined multiple times. In total we were able to capture 131 grilse and 99 salmon on the
Northwest Miramichi and 234 grilse and 867 salmon on the Southwest Miramichi. Included in those numbers
we captured 6 marked grilse and 1 salmon on the Northwest Miramichi, and 12 grilse and 23 salmon on the Southwest Miramichi
that were tagged and/or punched.
DFO will be able to use these numbers to improve the stock assessment projections.
Smallmouth Bass Introduction to Miramichi
Lake
In August of 2008, it was reported to DNR that a smallmouth bass was angled in Miramichi Lake.
Sampling by DNR and UNB verified that smallmouth bass were present in the lake, which infers that they were introduced
illegally to Miramichi Lake. Smallmouth bass are considered to be an invasive species to the Miramichi
River watershed. In fall of 2008, a counting fence barrier with fine meshed nets was installed at Miramichi
Lake to prevent smallmouth bass from escaping from Miramichi Lake into the Southwest Miramichi River. This
barrier was in place until ice up as it was thought that it may be damaged by ice or debris over the winter. The
area immediately below the barrier at Miramichi Lake was electrofished weekly (October 8 – November 6, 2008) in an attempt
to remove any bass which may have escaped from the lake. Over the course of the fall, six young of the
year smallmouth bass were removed. In January 2009, a risk assessment meeting was held to determine the
risk that smallmouth bass posed to Atlantic salmon on the Miramichi watershed. It was determined that in
the lake environment smallmouth bass would pose a high risk and in the Southwest Miramichi River a moderate risk to Atlantic
salmon.
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| Containment barrier at the outlet of Miramichi Lake |
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| Electrofishing Lake Brook for smallmouth bass |
In
2009 an assessment of Miramichi Lake and Lake Brook which enters the Southwest Miramichi was conducted to determine the distribution
and numbers of bass in Miramichi Lake and Lake Brook by the Miramichi Watershed Management Committee, Miramichi Salmon Association,
Department of Fisheries and Oceans and Department of Natural Resources. Over the course of the summer 64
smallmouth bass ranging in age from young of the year (age 0) to age 5, were removed from Miramichi Lake and the upper 350
m of Lake Brook by electrofishing, fyke nets or gill nets. Five age classes of smallmouth bass were captured
in Miramichi Lake in 2009 which indicates that smallmouth bass have spawned in at least three or four years in Miramichi Lake.
No smallmouth bass nests were found and bass were not able to be angled off nests in 2009 (water clarity makes finding
nests difficult). Smallmouth bass are likely distributed throughout the lake, as juveniles were found in
2009 on the western side of the lake and in 2008 on the southern side of the lake. The population of smallmouth
bass in Miramichi Lake appears to be successful at spawning year after year, individuals appear to be growing rapidly and
young of the year are attaining sizes for successful over-wintering. 2009 was a relatively cool year in
terms of temperature and years where temperatures are warmer could allow an increased growing season for these fish and increase
the number of young of the year bass that attain the minimum size for over-winter survival.
The funding to carry
out the assessment was provided to the MWMC by the NB Wildlife Trust Fund, Atlantic Salmon Endowment Fund, DNR and DFO.
The MSA also received funding from Service Canada for a technician to accompany the MSA biological team in the planning and
supervision of the activity, paid by the MSA.
In 2010, DFO will be supervising the activities at Miramichi Lake and they
have a plan to manually remove smallmouth bass from Miramichi Lake, unlike the plan called for by the MSA, which is to eradicate
the smallmouth bass by using rotenone to kill all the fish in the lake. The DFO plan is available by clicking here and the MSA will still participate in this plan.
Potential Impacts of Smallmouth Bass Introductions on Atlantic Salmon: A Risk Assessment
Smallmouth Bass Invasion of Gulf Region Rivers: Evaluating the Impact on Atlantic Salmon Populations
Atlantic Salmon and Smallmouth Bass Interactions in the Magaguadavic River, New Brunswick
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| Three different sizes of young of the year smallmouth bass |
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| Adult smallmouth bass removed from Miramichi Lake |
