AMJ99 Quarterly Rpt. sidebar
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(Quarterly Report for April-May-June 1999)
HABITAT
INVESTIGATIONS: Effect of Photoperiod on Overwinter Growth of Underyearling Sockeye Salmon
in Seawater
In previous studies at the Auke Bay
Laboratory (ABL), underyearling sockeye fry transferred to salt water following the
autumnal equinox grew little or none at all. Sockeye salmon, which normally
overwinter in fresh water, have a seasonal cycle in their ability to regulate plasma
sodium concentrations during a 24-hour seawater challenge, with declining abilities in
fall and winter. In Alaska, declining photoperiod may act as a much stronger cue than
temperature, which declines only gradually in the fall in subarctic waters. Due to
the large number of endemic underyearling stocks of sockeye salmon that migrate directly
to sea following emergence, Alaskan hatcheries are exploring the feasibility of fall
transfer into net-pens of hatchery-reared fry. What is the best time for saltwater entry
and what factors influence that timing?
Groups of underyearling sockeye
salmon (~2 g) were introduced into saltwater tanks 2 weeks prior to the fall equinox,
during the equinox, and 2 weeks following. All groups were reared for 8 months
(September-May) in saltwater tanks to determine the relative effects of photoperiod,
salinity (20 and 30 ppt), and temperature (4E and 8EC) on overwinter growth. Growth
in all groups fell from greater than 2 percent body weight per day (BWD) to less than 0.5
percent BWD following the equinox, but there was no differences in overwinter growth due
to entry timing. Fish transferred to reduced salinity (20 ppt) prior to the equinox had
significantly better initial growth than fish transferred directly to salt water at the
same time. This differential in growth did not persist past the winter solstice.
Fish reared at 4EC had virtually no overwinter growth in contrast to a growth rate
of 0.3-0.5 percent BWD among fish held at 8EC. These data suggests that
photoperiod and salinity are important variables influencing overwinter growth of
underyearling sockeye salmon in salt water.
By Adam Moles.
Exxon
Valdez Oil Spill Studies Continue
Field work was initiated early in
the field season with several rounds of sampling of mussels from oiled mussel beds in
Prince William Sound and for pristane as an index of copepod abundance.
Also, over 175,000 pink salmon fry
were marked and released at the Little Port Walter field station as part of a long-term
oil exposure experiment designed to test long-term effects of oil exposure on reproductive
viability when these fish return as adults in fall 2000. In September 1998,
200,000 pink salmon eggs were fertilized and incubated in water contaminated by
percolating through gravel coated with Alaska North Slope crude oil. Incubators with
uncontaminated gravel were paired with those containing two other exposure levels, the
highest of which was equal to the Alaska State Water Quality Standard. In May, over
175,000 survivors were marked and released, so that returning adults can be identified and
spawned. The objectives of this study are to confirm field observations of reduced
reproductive ability resulting from embryonic exposure to oil. In addition, long-term
effects on marine survival and growth will be correlated with the activities of biomarkers
such as histopathological damage and cytochrome P450-A1A activity observed when fry were
emerging from incubators.
By Jeep Rice.
New Web
Page
The AFSC/ABL Exxon Valdez Oil Spill
web pages have been updated and expanded.
The site provides information on current Exxon Valdez Oil Spill (EVOS) Trustee
Council-funded projects, reports, posters, and a bibliography produced by Habitat Program
researchers.
By Mandy Lindeberg.
NOAA/HAZMAT Cooperative
Field Study
The ABL participated in a 2-week
cooperative NOAA- HAZMAT (Hazardous Materials) field study in Kachemak Bay, Alaska,
to assist researchers with algae identification and to initiate groundwork on
an algal field guide.
Study objectives include enumeration
of existing epibiota study sites, a new Fucus recovery/senescence study,
preliminary scoping for infauna/grain size study, and a preliminary algae field guide
project. Major efforts on the algae field guide involved sample collection, herbarium
production, and field/laboratory photography for incorporation into a prototype field
guide (digital and hardcopy). The field guide will describe marine macro algae of the
Kachemak Bay habitat and will serve as an aid for researchers and an educational tool for
students.
The study represents the first
official NOAA use of the Kasitsna Bay Laboratory since Kasitsna Bay was designated a
National Estuarine Research Reserve last year. As an undisturbed habitat, Kasitsna
Bay will provide a baseline for years to come against which disturbed habitat such as
Prince William Sound can be assessed.
By Mandy Lindeberg.
Duck Creek
Selected as Showcase Watershed
Duck Creek has been selected as a
National Showcase Watershed for demonstrating stream corridor restoration. The
Showcase program is a key part of the Clean Water Action Plan announced in 1998. In May
1999, the Federal Interagency Stream Restoration Working Group, representing 15 Federal
agencies, selected Duck Creek as 1of 12 watersheds in the Nation to be showcased for
stream corridor restoration activities. Activities in each of the 12 watersheds will
be nationally publicized to increase public awareness and promote the use of the concepts
outlined in the Working Group publication (October 1998) Stream Corridor
Restoration: Principles, Processes, and Practices". K Koski and Mitch Lorenz will
contribute content for an internet site being set up by the Working Group. The Duck
Creek Watershed Management Plan will also be nationally publicized as part of the Clean
Water Action Plan.
By K Koski.
Restoration
Projects Proposed for Duck Creek
The U.S. Army Corps of Engineers
(COE) has proposed eight restoration projects in the Duck Creek watershed to be funded
through a habitat restoration program under Section 206 of the Clean Water Act. The
projects are planned over a 5- year period at an estimated cost of $5.2 million. The COE
proposal, based on projects outlined in the Duck Creek Watershed Management Plan, was
supported by the City-Borough of Juneau (CBJ). A letter of intent was filed by CBJ
to help sponsor the 35 percent match required by the projects.
By K Koski.
OCEAN
CARRYING CAPACITY: Survey of Salmon in Northeastern Pacific Ocean
During May 1999 ABL scientists
conducted a survey of ocean distribution of immature and maturing salmon along the 165E
and 145EW longitude meridians across the known southern limits of salmon
distribution, on the high seas of the Northeastern Pacific Ocean. The work is part of a
cooperative international effort coordinated by the North Pacific Anadromous Fish
Commission to examine distribution, growth, and survival of Pacific salmon during their
ocean life. The cruise covered over 4,000 nautical miles (nmi) and was carried out on the
chartered fish vessel Great Pacific, a 38-m stern trawler. Sampling gear was a
midwater rope trawl towed near surface at 5 kts., with typical spread to 18 m depth and 52
m width. Salinity-temperature profiles were measured with a CTD
(conductivity-temperature-depth) meter following each tow. The survey departed from Dutch
Harbor on 3 May and began sampling nearshore on the Bering Sea and North Pacific sides of
Unalaska Island, then proceeded south along the 165EW longitude line to lat. 38EN,
ran east to long. 145EW , worked north to the Cape St. Elias vicinity, and ran to Kodiak
to disembark scientists on 24 May. With 56 successful tows completed, the total catch of
salmon was 1,159 fishes, including 501 immature and 658 maturing salmon. No juvenile
(age-0) salmon were taken. Immature salmon included 236 chum, 246 sockeye, and 19 chinook.
Maturing salmon included 253 chum, 196 sockeye, 185 pink, 22 coho, and 2 chinook. The
survey took 521 salmon from Unalaska Island down long. 165EW, and 638 salmon along long.
145EW. A total of 62 salmon were tagged during the cruise, 34 with archival
(thermal) tags and 28 with standard disc tags only. Thermal tags were placed on 24
sockeye, 8 chum, and 1 each coho and chinook. Standard disc (only) tags were placed on 17
sockeye, 10 chum and 1 chinook. Two tags were later recovered. One thermal tagged chum
salmon released near lat. 56EN, long. 145EW, was recovered a month later 700 nmi west in
Unimak Pass. One sockeye with thermal tag that was released near lat. 5EN, long. 146EW was
recovered 24 days later in Chignik Lagoon, over 500 nmi west.
A primary finding of the survey was
that salmon of all species and age groups were discretely distributed on the high seas,
with little evidence of any mixing or nearby occurrence. Other fishes taken on the cruise
included walleye pollock, Pacific cod, rockfish, sablefish, daggertooth, lancetfish,
king-of-the-salmon, lanternfish, Pacific pomfret, smooth lumpsucker, spiny dogfish, salmon
shark, blue shark, Pacific lamprey, and unidentified specimen, possibly a little known
deepsea group, resembling the Melamphaidae or Diretmidae. Invertebrates in catches
included salps, scyphozoan medusas, and squid. Sea surface temperatures ranged from 3.8EC
at Cape Cheerful in the eastern Bering Sea to 14.4EC along the 38EN line at 157E long.
By Dick Carlson.
GROUNDFISH
INVESTIGATIONS: Adaptive Sampling Study of Rockfishes in the Gulf of Alaska
A Sea Grant Partnership Grant study
initiated by the ABL and the University of Alaska Fairbanks (UAF), Juneau Center for
Fisheries and Ocean Science (JCFOS), began 12 June in Seward, Alaska, aboard the chartered
fishing vessel Unimak and was scheduled to finish on June 29. This is the second
year of a 2-year grant to UAF-JCFOS to investigate a new sampling design for slope
rockfish (Sebastes spp.) adaptive sampling. Data are also being collected to
help determine sampling protocols in the NMFS fishery observer program. Scientists
from UAF, and the AFSCs ABL, Resource Assessment and Conservation Engineering
Division (RACE), and Resource Ecology and Fisheries Management Division (REFM) have
participated in the preparation, planning and field data collection.
Presently, Center scientists rely on
results from bottom trawl surveys that use stratified random sampling to determine
estimates of abundance (biomass) for various groundfish species. Random sampling is
suspected to be inefficient in estimating abundance of species that aggregate in localized
areas. Biomass estimates for rockfish often show large fluctuations from survey to
survey which do not seem reasonable given the slow growth and low natural mortality rates
of all Sebastes species.
Adaptive sampling is a relatively
new technique which, to date, has seldom been used in fisheries applications.
However, it appears to be particularly appropriate for sampling populations with a
clustered distribution, such as that observed for many rockfish species. In adaptive
sampling, random or systematic sampling is initially used to locate concentrations of the
targeted species, and is then followed by intensive sampling in the vicinity of the
concentrations.
This study is focused on three
commercially important species of slope rockfish: Pacific ocean perch (Sebastes
alutus)
(POP), shortraker rockfish (S. borealis), and rougheye rockfish (S.
aleutianus).
The net used was equipped with tire gear to facilitate trawling over rough
substrate, and the vessel was allowed to retain the catch to partially defray the costs of
the charter. The experiment is being conducted in the West Yakutat area in the
eastern Gulf of Alaska. The study area covers the upper continental slope to a depth of
500 m.
Participants on the cruise from ABL
were Dave Clausen, Jon Heifetz (co-principle investigator), Chris Lunsford, Pat Malecha,
Dean Courtney, and Dave Csepp; from UAF were Professor Terry Quinn (co-principle
investigator) and graduate students, Dana Hanselman and Andrew Matala; and from the AFSC
Observer Program, Sandi Neidetcher. Sampling during the cruise was scheduled for 24 hours
per day with Heifetz and Clausen as alternating field party chief.
1999 Sablefish Longline
Survey Underway
The 1999 sablefish longline survey
began 28 May in Dutch Harbor, Alaska. This was the twenty-first annual standard
longline survey. The survey is conducted by the Centers ABL and RACE Divisions
and covers the Gulf of Alaska annually and the Bering Sea and Aleutian Islands in
alternate years. The survey charter fishing vessel Ocean Prowler sampled
Bering Sea stations during the first leg. During the second leg, the vessel will finish
the Bering Sea and Western Gulf stations, then transit the Gulf of Alaska, conduct
seamount sampling, and port in Ketchikan. The survey will then begin at Dixon Entrance and
progress westward to complete the Central Gulf Area around 3 September. Chief
scientist for the first leg was Larry Haaga of the RACE Division, and Nancy Maloney of the
ABL is the chief scientist on the second leg.
The survey catch rates are critical
in the determination of the annual Allowable Biological Catch (ABC) of sablefish. In
addition to indexing sablefish abundance, sablefish, shortspine thornyheads, and
Greenland turbot will be tagged and released with Floy anchor tags during the survey.
Length-weight data and otoliths are collected from sablefish. A surface gillnet will
be deployed at night to sample juvenile sablefish (ages 0 and 1). Sightings of short tail
albatross will be recorded.
Age-structured
Model for Gulf of Alaska Northern Rockfish
The northern rockfish, Sebastes polyspinis, is one of the most abundant and commercially valuable members of its genus
in Alaska waters. As implied by its common name, this fish has one of the most
northerly distributions among the more than 60 species of Sebastes in the north
Pacific. Bottom trawl surveys of the Gulf of Alaska and Aleutian Islands region
indicate that northern rockfish is the second most abundant rockfish species in these
regions, surpassed only by Pacific ocean perch (S. alutus). Since 1990,
northern rockfish has supported a valuable domestic trawl fishery in Alaska. For the Gulf
of Alaska region alone recent catch levels have been around 5,000 metric tons (t); gross
wholesale value of this fishery was estimated at $4 million in 1995.
The stock assessment of northern
rockfish used to recommend catch quotas has relied almost entirely on biomass estimates
provided by NMFS trawl surveys. The recent Rockfish Stock Assessment Review
conducted by an outside review team expressed concern about the reliability of survey
biomass and the use of average survey biomass as the estimate of exploitable biomass for
many of the rockfish stocks. The review team specifically recommended attempting
age-structured assessments of northern rockfish to improve the quality of the stock
assessment. Age-and-length composition data are available from the surveys and
length composition data are available from the fishery. Otoliths were taken from the
1998 fishery for age composition data.
In FY98 the AFSC Rockfish Working
Group funded a contract to construct an age-structured stock assessment model for northern
rockfish, incorporating fishery catch data, survey abundance indices, survey age
compositions, and survey and fishery length compositions. Programming of the model
has been completed and initial testing indicate validity of basic model structure and
program coding. The model was constructed using AD Model Builder computer software.
The model now will be further tested and evaluated prior to actual application in
the determination of northern rockfish ABC recommendations.
Fishery
Data Evaluated For Incorporation in Sablefish Assessment Model
Since 1979, annual longline surveys
have been conducted on the upper continental slope in the Gulf of Alaska, Aleutian
Islands, and eastern Bering Sea. Data from these surveys are a major component used
in computing relative population indices for sablefish. Steady declines in survey
catch rates of sablefish have led to reduced fishery quotas in recent years. Concern
has been expressed that fishery catch rates have remained strong in some areas despite the
apparent decline of sablefish populations seen in the survey. Extensive fishery
information is available through data collected by the domestic observer program.
However, fishery catch rates may not be representative because gear configurations
and fishing patterns may vary. Fishermen also target concentrations of fish, even as
geographic distribution shrinks when abundance declines. A draft report calculating
preliminary CPUEs for the fishery and comparing them to the survey information is under
review.
In Situ Studies on
Alaskan Coral
Colonies of the gorgonian coral (Swiftia sp). were located during cruise 99-07 aboard the NOAA ship John N. Cobb which
was completed 4 June. Numerous colonies were found at sites near Tenakee Inlet and
the Little Port Walter field station. These sites will be revisited during cruise
99-10 in July, and divers will deploy long-term temperature recorders, collect baseline
size measurements of individual colonies, and deploy a variety of potential settling
substrate types. This may provide opportunities for growth, recruitment, and habitat
studies that could lead to new insights into the biological requirements and longevity of
corals. Although the primary cruise mission of finding red tree coral
(Primnoa sp.) within safe scuba depths was not successful, sites along the gulf coast of Prince of
Wales Island will be explored during cruise 99-10 in July in hopes of finding shallow
water colonies of that species where similar studies can be initiated.
By Phil Rigby.
MARINE
SALMON INTERACTIONS: Bear and Firearms Safety
The ABL has developed a training
program for its employees doing field work in areas with high brown and black bear
concentrations. Also, policy has been established at permanent field stations to
minimize the interaction of local bears and field personnel. The policy
involves minimizing man-made attractors and using aversive conditioning to keep bears away
from high human-use areas.
The training program covers a range
of topics from basic identification, species and sex differences, to bear behavior
and avoidance techniques. Training materials include video and written information from
the U.S. Forest Service, the Canadian Ministry of Forestry, the Alaska Department of Fish
and Game, and the National Rifle Association.
Basic firearms safety instruction
and rifle/shotgun training are given by an N.R.A. instructor. Yearly qualification is
required for field personnel who need to carry firearms. In the past, instruction
was given by private instructors on their own time or by individuals from other agencies.
The instruction is now given by ABL staff certified by the N.R.A. The emphasis of the
firearms training is safety. During annual certification staff must demonstrate safe
gun handling and marksmanship. The goal of the training is to educate and inform personnel
in order to minimize negative bear encounters and to promote safe and responsible gun
handling in the field.
By John Joyce.
ESA
Steelhead Research
Research at ABLs Little Port
Walter field station is being conducted to determine long-term effects of inbreeding
depression (genetic damage caused by the breeding of related individuals) that
typically occurs in small, remnant populations of animals that frequently have been placed
in captivity for protection. Various techniques are currently being tested in
captive populations of many different endangered animals in many parts of the world.
The techniques span the range of human involvement from complete control of breeding
by maintaining complete pedigrees and identities of all individuals in the population with
controlled, artificial culture of offspring to quasi-natural methods which provide a
natural setting and as near normal breeding interactions and natural rearing of offspring
as possible under a protective protocol. One method being considered for
preserving important genetic resources of critically endangered anadromous steelhead
populations is to sequester a portion of the at risk population throughout its life cycle
in a natural freshwater environment that can be protected, for perhaps decades, until its
natural habitat has been restored. The population would be allowed to
reproduce naturally, however, the ocean migratory phase would be curtailed.
Scientists at the Little Port Walter
station are testing the effects of 70 years of freshwater sequestration, using populations
of steelhead that were stocked into fishless lakes with natural migration barriers during
the 1920s and 1930s, on important life history characteristics such as genetic
variability, bilateral asymmetry, spawning timing, development rate, growth rates,
survival in captive and wild environments, age at maturity, smolting rates, and marine
survival.
To date, more than 200 families of
anadromous steelhead and resident rainbow trout and their crosses have be created and
studied. Over 6,000 fish from 74 families are being cultured in captivity to
maturity and over 20,000 coded-wire-tagged smolts have been released. Preliminary
indications are that steelhead populations that have been held completely in fresh water
for 70 years can still produce significant, although fewer, numbers of smolts as their
ancestral stock. It is still unknown if marine survival rates of the smolts
differ however. Significant genetic differences exist between the sequestered and
ancestral populations, however, information is still being analyzed to determine if
the differences were caused by the long period of sequestration or the original
establishment of the freshwater population.
By Frank Thrower.
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