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Oregon State University College of Oceanic and Atmospheric Sciences


April 1997




Southeast Bering Sea Carrying Capacity - juvenile pollock habitat and biophysical indices




Ric Brodeur and Jeff Napp (NOAA/Alaska Fisheries Science Center, (206) 526-4318, (206) 526-4148, Fax: (206) 526-6723), and

Phyllis Stabeno and Jim Schumacher (NOAA/Pacific Marine Environmental Lab., (206) 526 6453, (206) 526-6197, Fax: (206) 526-6485).


June 30 - July 14, 1997


Scientist in charge: Matt Wilson, NOAA/AFSC (contact for questions)
(206) 526-6522,

Other scientists:

Sigrid Salo (PMEL), Jeremy Higgins (PMEL), Lorenzo Ciannelli (Univ. Wash.), Lisa Britt (AFSC), Steve Porter (AFSC), Jay Clark (AFSC), Chris Baier (Univ. Wash.), Gregg Savage (UCal Irvine), TBA (Ucal Irvine), Sarah Pautzke (WWU).


The southeast Bering Sea supports an abundance of species that are important economically and culturally. Ecosystem-level management of this region is desirable but requires some knowledge of the governing ecological mechanisms. Based on abundance and commercial value, walleye pollock are an important part of this ecosystem. Variations in pollock survival would thus likely have a large impact on the regions' biotic and economic characteristics. This cruise addresses two goals of the Southeast Bering Sea Carrying Capacity (SEBSCC) Program. The first is to understand juvenile pollock-habitat interactions. These interactions will be studied by conducting site-intensive sampling along transects which cross a tide/wind-induced frontal region surrounding the Pribilof Islands. Fluctuating environmental conditions are expected to be an important source of variation in pollock survival. Thus, the second SEBSCC goal addressed by this cruise is to occupy hydrographic stations in an effort to develop biophysical indices useful for monitoring key physical and low-trophic level aspects of the southeast Bering Sea region.


On June 30, approx. 10:00 ADT, the ship will depart Dutch Harbor and steam to the southern end of the Biophysical Transect (53° 21.5'N; 168° 42.0'N). Hydrographic stations are then taken in order along the transect according to the attached Biophysical Station Table and Map (Table 1, Figure 1). The order in which the Biophysical Canyon Transect and the Juvenile Habitat Transects are occupied depends upon timing and travel efficiency (Tables 1&2, Figures 1&2). The cruise will end when the ship arrives back in Dutch Harbor at 9:00 am (ADT) on July 14.


A) Biophysical Monitoring.

1. A total of 38 stations will be occupied for this cruise objective. Table 1 lists the station locations and station-specific operations, in order of occupation (Figure 1). In brief, a CTD will be accomplished at each station. At selected stations, (see Table 1) samples for chlorophyll and nutrients will be taken using Niskin bottles on the CTD rosette. We will then tow 20 and 60 cm bongo frames (150 and 333 µm mesh, respectively) on the same wire for collection of zooplankton. Water sampling at Moorings 2 and 3 may require several CTD casts to obtain the requested chlorophyll replicate samples. When doing deep CTD casts, make certain that any ancillary instruments on the CTD (e.g. fluorometer) are rated for the depth of the cast (1500 m at the deepest stations).

2. Canyon Transport ­ Table 1 lists the stations locations and station-specific operations (Figure 1). Order of occupation will be determined by the Chief Scientist. In brief, a CTD will be accomplished at each station with one water bottle sample at 5 m for nutrients. The fluorometer should be on the CTD, but no chlorophyll samples will be taken. The CTD cast is followed by a tow of the 20 and 60 cm bongo frames (150 and 333 µm mesh, respectively) on the same wire for collection of zooplankton.

B) Sampling to satisfy the juvenile pollock habitat objectives is as follows:

1. There are four Juvenile Habitat Transects detailed in the Table of Juvenile Habitat Stations but the order in which they are sampled will depend on timing and travel efficiency. Sampling each transect will take approximately 20 hours and consists of three passes. The first pass along each transect will be to conduct a CTD cast and a bongo tow (with 20 and 60 cm nets) at each of 7-10 stations (Table 2, Figure 2) (approx. 12 hrs). Two more passes will be necessary: one to collect acoustic data along the transect (approx. 3 hrs) and the other to collect micronekton at each of three locations (approx. 5 hrs). These three locations will be determined either by the degree of thermal stratification or simply the locations sampled during September 1996 (Table 2), and sampling will be accomplished using the Methot trawl. Both of the latter two passes on each transect should be done at night. Allowing for 1 hour of twilight before and after sunrise and sunset, there will only be about 5 hours of nighttime (ADT: sunrise, ~06:40; sunset ~00:10) so it may be logistically difficult to meet this diel constraint. Second choice, is to run the acoustic pass during the day and collect micronekton at night (to reduce gear avoidance effects). If acoustic passes are made during the day, every opportunity should be made to identify the echosign. Removing diel differences will facilitate comparisons among stations and transects but will add to the estimated time necessary to complete the sampling of each transect (20 hrs). Accounting for the diel sampling constraint and travel time between transects we estimate that it will take about 7 days to complete the sampling of all four transects.

2. If time permits, some transects or stations may be repeatedly sampled at different diel periods or with different gears. We will also attempt to use the IKMT/MPS net to resolve vertical or meso scale horizontal patterns in fish distribution.

3. The bird biologists (Ucal Irvine) will make observations of seabird counts along and across the outer shelf of the southeastern Bering Sea, and in the vicinity of the Pribilof Islands. Conditions permitting, they will also attempt to collect birds as opportunity permits using a 12-gauge shotgun and deployed in the Zodiac Mark II.

C) Methods for fishing each gear is described briefly. More details regarding the typical deployment/retrieval routine for these gears is attached (the routine for deploying and retrieving the IKMT/MPS will be established on an earlier cruise (WE97-06A, 4-9 June 1997)).

1. The CTD and bongo nets will be fished to within 5 m of bottom except as specified in Table 1. On the CTD care must be taken to not exceed the maximum depth ratings of the attached instruments. We hope to monitor the bongo depth using a SeaCat terminated to the end of the 0.322" (5/16) wire on the trawl winch and connected to a deckbox and Personal Computer in the dry lab. This will require slip rings. It is expected that three scientists, 1 winch operator, and one crewman (or marine technician) will be necessary when fishing the CTD and bongo nets. The 20 cm bongo net will be attached to the wire above the 60 cm bongo and the array will be fished off the starboard quarter using the trawl winch, boom, and boom crutch and maintaining a wire angle of 45 degrees (only the sample from Net 1 of each bongo net will be preserved). Deploying and retrieving the bongo nets may each require two scientists, one crewman, and a winch operator.

2. Both the Methot net and the IKMT/MPS net will be fished off the stern. The Methot net will be fished over an oblique path down to 10 m off-bottom using the stern A-frame and the coring winch. The IKMT/MPS net will be fished variously depending on echosign. Realtime depths of the Methot and the IKMT/MPS will be accomplished using Scanmar equipment (a small depth sensor is attached to the net and a hydrophone draped over the side at a depth of about 3 meters). We will also monitor the temperature at depth using a mini bathythermograph (MBT) which is a self-contained unit that attaches directly to the gear and records for a predetermined time. Deploying and retrieving the Methot and the IKMT/MPS may each require two scientists, two crewmen, and a winch operator.


Most of the needed equipment will be loaded using the ship's crane in Seattle (12 May, Monday) but ScanMar equipment (about 100 lbs total) will be loaded in Dutch Harbor (29 June, Sunday). All gear will be off-loaded in Dutch Harber on 14 July (Sunday) beginning shortly after the ship docks at 9:00 am (ADT). It is expected that off-loading will take approximately 2 hours (Hugh Milburn expects loading for the next cruise to take about 4 hours - this means that the scheduled "touch-and-go" will actually include at least 6 hours at a dock). Storage in Dutch Harbor will be available with advance notice at the FTS facility (FTS, Dutch Harbor / Vessel Support and Supply Center / P.O. Box 1085 / Dutch Harbor, AK 99692 / Tel. 907 581-2490 / Fax. 907-581-2491).


None will be used.


20 liters Formalin (37% formaldehyde)
12 liters Sodium borate solution
300 mls 95% Ethyl Alcohol (EtOH) (Jerry Hoff)
0.05 g MS-222
~10 liters 95% Ethyl Alcohol (EtOH) (Ucal Irvine)
12 gauge shotgun (Ucal Irvine)


OSU Marine Technicians: 1 requested
Electronics Technician: 1 requested

Coring winch and stern A-frame for fishing Methot; Trawl winch (5/16" 3-conducter cable) and boom crutch for fishing bongo nets over starboard quarter and IKMT/MPS off the stern; Electromechanical swivels; Winch slip rings.

Shipboard CTD system (with spare sensors); associated data display, logging, and output systems; Sixteen 5 liter Niskin bottles (includes 4 spares); SeaTech Fluorometer.

Underway fluorometer and thermosalinograph, every 60s log: GMT date, time, lat., long., temp., salinity, fluoresence, bottom depth.

GPS navigation system and INMARSAT phone/fax system for occasional scientific use. The Ashtech system must be functioning for use with GPS navigation.

Sea-Bird 911+ CTD with

16-18 5-liter Nisken bottles, mounting pins and spares
CTD PAR with cables and mount
CTD fluorometer with cables and mount
CTD transmissometer with cables and mount
CTD stand
CTD weights

Sea-Bird deck unit
tape recorder or VCR
CTD computer

Ship speed, heading, high resolution position, wind speed, wind direction, TSG conductivity, and TSG temperature should be recorded on a computer every 60 seconds. This data should be backed up daily.

Wet and dry bulbs, air temperature and relative humidity should be manually recorded by the bridge every four hours. The weather record will begin at athe time of the first station and will end at the last sstation, or as specified by the Chief Scientist. If the bridge watch is unable to record the weather, please notify the scientist on watch.

A copy of the latest calibration sheets/documentation for all WECOMA instrumentation used should be provided.

Fill out a Marine Operations Abstract (MOA) form, provided by FOCI. This includes: GMT date, GMT time, position, depth, and operation. One line of the MOA should be completed by bridge personnel for each operation at each FOCI station. The standard time for recording data - both on computer and on forms - will be GMT.

Sample processing space (sink w/ hood for formalin, seawater hose for rinsing nets on deck and for rinsing codends/sieves in lab).

Location in the main dry lab to set up readouts for: wireout, GPS, bottom depth, ship's speed, and deck units for SCANMAR (depth of Methot and IKMT/MPS), Sea-Cat (depth of bongo and Tucker), and MPS.

Miscellaneous: Two portable chest freezers (each 15 cu. ft.) for nutrient and chlorophyll samples; the storage van that fits on main deck under trawl winch; plain paper copier.


see attached gear list


The multiple plankton sampler (MPS), which attaches to the aft end of the Isaacs-Kidd midwater trawl (IKMT), is packed in a plywood box (approx. 3'x6'x6') (~400 lbs total) and may be stowed on the deck if somewhat protected from spray and rain.

All of the following may be stored on the open deck:
1) Methot frames, depressors, and bridles (~800 lbs total),
2) IKMT spreader bar, depressor, and bridle (~200 lbs total),
3) Tucker "frame", and bridles (~200 lbs total)
4) 60 cm bongo frame and weight (100 lbs total)
5) 20 cm bongo frame


Name: Robert Sommer
Address: NOAA, AFSC, 7600 Sand Point Way N.E., Seattle, WA 98115
Account Number (or number to reference):




Map and Table of Biophysical Transects/Stations
Map and Table of Juvenile Habitat Transects/Stations
Gear List
Gear Deployment Procedures

EcoFOCI Project Office
7600 Sand Point Way NE
Seattle, Washington 98115
Comments and information:
  EcoFOCI Coordinator

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