AMJ 2000 Quarterly Rpt. AMJ 2000 sidebar
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(Quarterly
Report for April-May-June 2000)
Dispersant
Effectiveness Testing Begins at ABL
The environmental repercussions of not treating an
oil spill were amply demonstrated by the damage that
ensued from the Exxon Valdez oil spill. Research
conducted by the Auke Bay Laboratory following the
spill demonstrated decade-long persistence of the
oil in nearshore sediments. This persistent
source of petroleum hydrocarbons is bioavailable and
toxic to nearshore and estuarine fish eggs at parts
per billion concentrations. Dispersal of the
oil in the water column is viewed as a possible
means of eliminating this threat to the productive
nearshore environment. It remains to be seen,
however, if dispersants are chemically effective in
dealing with Alaskan spills.
While dispersants are often the primary method used
in Europe for treating a spill, in the United States
dispersants are used only when certain stringent
conditions are met. The decision to use
dispersants following an oil spill is contingent on
balancing the obvious advantages of using
dispersants against the potential for acute damage,
both from the dispersant and from the synergistic
interactions of oil and dispersant. Evaluating
these difficult tradeoffs is one of the most
challenging jobs facing an on-site coordinator.
The decision to use dispersants will hinge
initially on whether the stockpiled dispersant in
Alaska (Corexit 9527) will prove effective in
dispersing the oil under regional conditions. Initial
research suggests that both Corexit 9527 and its
likely replacement Corexit 9500 may be less
effective in dealing with Alaska North Slope Crude
oil than against other types of oil. The ABL
is conducting a series of effectiveness tests to
determine what percentage of the oil is dispersed at
combinations of cold temperatures (4°-15°C),
reduced salinities (15‰-25‰), and a
variety of weathering states (fresh, 26% weathered,
and mousse).
By Adam Moles.
Army Corps of Engineers Proposes Aquatic
Habitat Restoration for Duck Creek
National recognition of efforts to restore
aquatic habitat in Duck Creek has prompted the U.S.
Army Corps of Engineers (COE) to propose up to $4.0
million in aquatic habitat restoration projects for
the Duck Creek watershed. That funding is
contingent on a 35% match from sponsors such as the
City/Borough of Juneau (CBJ), Mendenhall Watershed
Partnership, and Trout Unlimited.
Awards to the Duck Creek Advisory Group (DCAG) from
Coastal America and the Federal Interagency Stream
Restoration Working Group (FISRWG) led to the
Corp’s involvement. In 1999, the DCAG
received a partnership award from Coastal America,
and Duck Creek was selected by the FISRWG as one of
12 national demonstration watersheds. The
Coastal America award was for facilitating Federal
agency cooperation in state and local efforts to
address specific environmental problems along our
Nation’s coasts. As part of the Clean Water Action
Plan, the FISRWG is promoting Duck Creek as one of
12 watersheds in the Nation that best demonstrate
the principles and practices of stream corridor
restoration.
Federal agencies involved in the project include
National Marine Fisheries Service, the Environmental
Protection Agency (EPA), and U.S. Fish and Wildlife
Service (USFWS). The AFSC provided personnel
and secured grant funding for several Duck Creek
projects through the NOAA Community-Based
Restoration Program. The EPA provided nearly
$450,000 in funding for research and demonstration
of nonpoint source pollution treatment in the Duck
Creek watershed. The USFWS provided personnel
and grant funding through Partners for Wildlife and
other programs.
The City/Borough of Juneau is the primary local
sponsor of the proposed COE projects. The CBJ
has agreed in principle to support the projects by
matching up to 35% of the COE expenditure. Most
of that match will likely be “in-kind” services
such as providing rights-of-way, construction
materials, or engineering services.
The proposed projects are being designed primarily
to restore aquatic habitat for fish and wildlife.
In Duck Creek’s urban location, however,
those projects will also address a number of other
issues such as public health and safety, water
quality, and flooding. ABL scientists K Koski
and Mitch Lorenz are currently being funded by the
COE to complete a feasibility study for the eight
projects proposed for COE funding by the end of FY
2000.
By Mitch Lorenz.
Stock Origins of Illegally Captured Salmon on
the Drift-Net Vessel Arctic Wind
(view
"Origins of Salmon Seized From the F/V Arctic
Wind" file (.pdf format))
On 1 May 2000 the U.S. Coast Guard (USCG) spotted
the 177-ft fishing vessel Arctic Wind
illegally driftnet fishing about 600 miles southwest
of Adak Island. The Honduran-registered,
Korean-owned, Russian-crewed vessel was stopped and
boarded by the USCG on May 8. Two nets from
the vessel were retrieved on 10 May, approximately
300 miles from Adak Island. The vessel was
escorted to Adak and samples of the catch were sent
to the ABL for stock identification and other
analyses. Samples included 492 chum salmon,
217 sockeye salmon, and 55 chinook salmon. The
remaining approximately 1,000 chum salmon were
delivered by the USCG to the food bank in Anchorage.
Of the sampled chum salmon, 464 whole and 28 gutted,
301 were processed for genetic analysis (whole fish
only), 474 for otoliths, and all 492 for scales.
Of the sampled sockeye salmon, 61 were whole,
146 were gutted, and 10 were headed and gutted.
The headed-gutted sockeye salmon were not
sampled; all the remaining fish were sampled for
genetic, scale, and brain parasite analysis. The
gutted fish had been sprinkled with rock salt, which
may have been an attempt to firm up the flesh, and
may interfere with the genetic analysis. All
of the 55 chinook salmon, 24 whole and 31 gutted,
were sampled for genetic, scale, and brain parasite
analysis.
Age determination of fish by scale analysis,
presence of brain parasites in sockeye and chinook
salmon, and genetic stock identification analysis by
protein electrophoresis will be used to identify the
region(s) of origin of these fish. The genetic
analysis is ongoing and so far sample quality has
been very good. The chum salmon otoliths will
be examined for hatchery thermal marks by the Alaska
Department of Fish and Game (ADF&G) Otolith
Processing Laboratory.
By Jon Poll, Chris Kondzela, and Chuck Guthrie.
Southeast Alaska Coastal Monitoring
The Southeast Alaska Coastal Monitoring (SECM)
project is a cooperative effort of the ABL Ocean
Carrying Capacity and Marine Salmon Interactions
Programs, which examines environmental relationships
of juvenile salmonids as they leave natal waters of
northern Southeast Alaska and progress through Icy
Strait to the outer coastal waters off Cross Sound.
Two cruises were completed this quarter for the SECM.
Joseph Orsi (Marine Salmon Interactions) was
Chief Scientist for the May 2000 John
N. Cobb Cruise JC00-05 and James Murphy
(Ocean Carrying Capacity Program) the Chief
Scientist for the June 2000 Cruise JC00-09. Bruce
Wing (Ocean Carrying Capacity Program) participated
on both cruises. Besides ABL staff, Craig
Chisolm (Northern Southeast Regional Aquaculture
Association) and Robert Spevic (biology instructor
from a private high school in San Francisco,
California) were volunteer assistants during the
June cruise.
The May cruise was restricted to oceanographic
sampling, during which temperature and salinity
profiles and zooplankton samples were obtained at 21
stations, and surface nutrient and chlorophyl
samples were taken at 15 stations. Because
juvenile salmon are usually either very rare or not
present at the sampling stations in May, we did not
conduct surface trawling.
A coordinated oceanographic, rope trawl and acoustic
survey for juvenile salmon aboard the NOAA research
vessel John N. Cobb and the research vessel
Quest was conducted between 26 June and 2 July 2000.
Sampling locations included four stations
along an offshore transect at Icy Point, four
stations along a transect in Cross Sound, nine
stations along a transect in Icy Strait, four
stations along the upper Chatham transect, and four
stations in the inshore waters. Zooplankton settled
volumes (SVs) were highest at the Icy Strait
stations and coincided with the highest catches of
juvenile salmon. Zooplankton consisted primarily of
small copepods and euphausiids. The increase in
zooplankton SVs at the Icy Point Station 40 miles
offshore was primarily due to the abundance of
Limacina.
A total of 5,396 fish and squid were captured with
the rope trawl, representing 15 different species.
Juvenile lingcod appeared to be more abundant
in June than in previous years in trawls taken over
the continental shelf. About three dozen
pelagic stage lingcod were taken, compared with
previous years when usually less than 10 juvenile
lingcod were taken during a cruise. Salmon
catches were predominately juveniles (n = 1,544):
juvenile chum salmon was consistently the most
abundant fish species captured (n = 917) and was
considerably more abundant than the other species of
juvenile salmon (sockeye salmon (n = 272), pink
salmon (n = 253), coho salmon (n = 93), and
chinook salmon (n = 9)). Juvenile salmon were
most abundant in Icy Strait. Mean fork lengths
of juvenile salmon varied by species. Coho
salmon had the largest mean length (165 mm),
followed by chinook (157 mm), sockeye (114 mm), chum
(106 mm), and pink (95 mm).
Hydroacoustic surveys were conducted along several
transects near the Icy Strait stations. Hydroacoustic
data were collected with a Biosonics DT4000 system
with a 150 kHz narrow beam (6E) transducer mounted
in a fin and towed along the side of the vessel. The
transducer was mounted in a side scanning
configuration with a downward tilt of 4E. The
hydroacoustic data will be processed to provide mean
backscattering area per unit of horizontal area and
then will be compared to the zooplankton and trawl
data.
By Bruce L. Wing.
Auke Bay Environmental Monitoring
Daily sea surface temperature and weather
observations at the Auke Bay Laboratory continued
through the winter and spring of 1999-2000. Sea
surface temperatures were about average compared
with the long-term mean (1978-2000). Air
temperatures were warmer than average and
precipitation was about average for the first half
of the year.
By Bruce L. Wing.
Monthly Mean Sea Surface Temperature (EC) |
|
Monthly Midrange Air
Temperature (EC) |
Year |
1999 |
2000 |
Mean |
|
Year |
1999 |
2000 |
Mean |
January |
4.1 |
3.9 |
3.6 |
|
January |
-2.9 |
-2.9 |
-4.1 |
February |
4.0 |
3.4 |
3.2 |
|
February |
-1.2 |
0.5 |
-1.1 |
March |
3.7 |
3.7 |
3.8 |
|
March |
-1.4 |
2.9 |
1.34 |
April |
6.0 |
6.3 |
6.2 |
|
April |
4.8 |
5.1 |
5.1 |
May |
9.1 |
10.4 |
10.0 |
|
May |
7.9 |
9.5 |
7.63 |
June |
13.7 |
13.3 |
13.4 |
|
June |
13.2 |
13.1 |
12.5 |
Monthly Precipitation (cm) |
|
Monthly Snowfall (cm) |
Year |
1999 |
2000 |
Mean |
|
Year |
1999 |
2000 |
Mean |
January |
18.8 |
5.6 |
11.7 |
|
January |
104.6 |
26.7 |
70.1 |
February |
6.0 |
3.2 |
10.0 |
|
February |
67.6 |
3.6 |
45.3 |
March |
5.6 |
11.6 |
8.5 |
|
March |
4.3 |
0 |
44.1 |
April |
14.0 |
14.1 |
7.5 |
|
April |
3.1 |
Trace |
5.0 |
May |
14.8 |
10.1 |
10.0 |
|
May |
0 |
0 |
1.0 |
June |
8.0 |
16.1 |
10.5 |
|
June |
0 |
0 |
0 |
2000 Longline Survey Under Way
The twenty-second standard longline sablefish
survey conducted by the Center’s ABL and Resource
Assessment and Conservation Engineering (RACE)
Division began 1 June in Dutch Harbor aboard
the survey charter vessel Alaskan Leader.
The survey covers the Gulf of Alaska annually
and the Bering Sea and Aleutian Islands region in
alternate years. The survey catch rates
are critical in determining the annual allowable
biological catch 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 data are collected on all major
species, including rockfish and grenadiers, and
weight data and otoliths are collected from
sablefish. Also, a small-mesh surface gillnet is
deployed at night to sample juvenile sablefish (ages
0 and 1), genetic tissue samples are taken from
rougheye rockfish, and sightings of short-tailed
albatross are recorded.
Scientists on the Alaskan Leader sampled
Aleutian Islands stations during the first leg,
Western Gulf stations during the second leg, then
transited the Gulf of Alaska for a port call in
Ketchikan. During the Gulf of Alaska transit, three
seamounts were sampled. Two of the three
seamounts fished, Surveyor and Pratt, were also
sampled last year. Sablefish catches were down
slightly at Surveyor and about the same as last year
at Pratt. The third seamount sampled this year
was Welker, about 100 miles southeast of Pratt.
Over 2,000 sablefish were caught on Welker.
About 300 sablefish were tagged and released
and 50 sampled for otoliths at each of the three
seamounts. Seven tagged fish were recovered from the
same seamounts where they were released last year.
One tagged fish, released off Kodiak in 1989,
was recovered on Welker Seamount. The third
leg of the survey began at Dixon Entrance and will
progress north and west to complete the sixth leg in
the Central Gulf Area around 3 September. Chief
scientists were, for the first leg, Larry Haaga
(RACE) and, for the second leg, Nancy Maloney (ABL).
By Nancy Maloney and Mike Sigler.
Sablefish Fishery Catch Rates
The number of sablefish caught during the annual
longline survey helps determine trends of abundance
over time. In recent years, survey catch rates
have steadily declined, indicating sablefish
populations in Alaska have decreased. Some
fishermen have expressed concern about this trend
because their catch rates have remained strong in
some areas in contrast to the decline indicated by
the NMFS survey. Since changes in abundance
estimates directly affect fishermen’s individual
fishing quotas (IFQs), survey trends are an
important issue to fishermen. To address
these concerns and to determine if the fishery and
survey are showing similar trends, the ABL is
utilizing commercial fishery data. The
addition of fishery data along with survey data will
expand the time frame during which CPUE is
represented in the assessment model.
Several sources of fishery data are now available to
ABL assessment scientists. Extensive fishery
information is available through data collected by
the domestic observer program since 1990. In
1997, a cooperative effort by the ABL and fishing
industry representatives established a volunteer
sablefish logbook program for vessels under 60 feet.
These vessels typically do not carry observers on
board and represent a large proportion of the
vessels operating in the eastern Gulf of Alaska.
Skippers of these vessels voluntarily supply
data which are provided to NMFS by their fishing
associations. Data include catch locations,
composition, and amounts and gear specifications
essential for standardization. In addition to
the volunteer logbook program, a required logbook
program was initiated in March 1999, which requires
vessels over 60 feet in length to maintain a logbook
documenting sablefish catch. The recent
addition of these logbook programs provides a large
amount of information which we can now use to
accurately estimate trends in fishery catch rates.
Using the fishery data, a standardized fishery catch
rate for each management region and year is computed
for comparison to survey catch rates. Catch
rates are standardized by set to account for
differences in hook spacing which can vary greatly
between vessels and gear. Standardizing the
data allows the analysts to compare the fishery data
to the survey data in different regions and years.
Catch rates are expressed as the number of
pounds caught per hook.
Figure 1. Average CPUE (pounds/hook) by region
for survey and
sablefish directed longline fishery data, 1990-1998.
The highest catch
rates for both fishery and survey data are in the
West Yakutat and East Yakutat/Southeast areas
(Figure 1 above). The fishery and survey catch rate
trends from 1995 to 1998 are similar in all Gulf of
Alaska areas except in West Yakutat. In West
Yakutat, the survey catch rate has declined steadily
since 1996. Fishery catch rate, however,
increased in 1997 followed by a decrease in 1998.
In other areas, the survey catch rate has
generally declined since 1995, whereas the fishery
catch rate appears steady from 1995 to 1998. Fishery
catch rates increased dramatically from 1994 to 1995
in all Gulf of Alaska regions. This increase
in catching ability is probably due to the
change from a “derby” to an IFQ fishery.
After accounting for the change to the IFQ fishery,
the results of this analysis indicate fishery and
survey catch rate trends from 1995 to 1998 are
similar in all Gulf of Alaska areas except West
Yakutat. These results are an important step towards
incorporating both survey and fishery data into the
management process. The establishment of two
logbook programs indicates a strong commitment from
the industry to help NMFS and increases the amount
of fishery information available for management
purposes. The fishery catch rate data from
this analysis has been added to the sablefish
assessment model and will assist in better
understanding the status of the sablefish population
in Alaska.
By Chris Lunsford.
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