NOAA Technical Memorandum NMFS-AFSC-13

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

February 1993

Comparisons Between Observed and

Reported Catches of Retained and

Discarded Groundfish in the Bering Sea

and the Gulf of Alaska, 1990-91

by

J. D. Berger
NOAA Technical Memorandum NMFS

The National Marine Fisheries Service's Alaska Fisheries Science Center uses

the NOAA Technical Memorandum series to issue informal scientific and

technical publications when complete formal review and editorial processing are

not appropriate or feasible. Documents within this series reflect sound

professional work and may be referenced in the formal scientific and technical

literature.

The NMFS-AFSC Technical Memorandum series of the Alaska Fisheries Science

Center continues the NMFS-F/NWC series established in 1970 by the Northwest

Fisheries Center. The new NMFS-NWFSC series will be used by the Northwest

Fisheries Science Center.

This document should be cited as follows:

 Berger, J. D. 1993. Comparisons between observed and reported 

catches of retained and discarded groundfish in the Bering Sea and the

Gulf of Alaska, 1990-91. U.S. Dep. Commer., NOAA Tech. Memo. NMFSAFSC-13, 89 p.

Reference in this document to trade names does not imply endorsement by the

National Marine Fisheries Service, NOAA.
NOAA Technical Memorandum NMFS-AFSC-13

Comparison Between Observed

and Reported Catches of Retained and

Discarded Groundfish in the Bering Sea

and the Gulf of Alaska, 1990-91

by

Jerald D. Berger

Alaska Fisheries Science Center

7600 Sand Point Way N.E., BIN C-15700

Seattle, WA 98115-0070

U.S. DEPARTMENT OF COMMERCE

Ronald H. Brown, Secretary

National Oceanic and Atmospheric Administration

John A. Knauss, Administrator

National Marine Fisheries Service

William W. Fox, Jr., Assistant Administrator for Fisheries

February 1993
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Notice to Users of this Document 

This document is being made available in .PDF format for the convenience of users; however, the 

accuracy and correctness of the document can only be certified as was presented in the original hard 

copy format. 

U.S. fisheries observers and U.S. processing operations each

submit a weekly record of fish catch and production. This report

compares these two sets of reports from the Bering Sea/Aleutian

Islands and the Gulf of Alaska Regions for 1990 and 1991.

Most observers aboard catcher/processors using trawl gear

reported a discard rate similar to that reported by the vessels.

For shoreside processing operations, the observed discard rate

from the delivering vessels was frequently 10-20 percentage

points higher than the discard rate reported by the shoreside

processors. Overall, observers reported higher amounts of total

catch than did their observed vessels.
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V

CONTENTS

Page

Introduction ................................................

Methods .....................................................

Results .....................................................

Catcher/Processor Overall Comparison ...................

Shoreside Plant and Mothership Overall Comparison ......

Comparison of Total Reported Catch to

Total Observed Catch ....................

Catcher/Processor Comparison by Target .................

1990 ..............................................

1991 ..............................................

Catcher/Processor Comparison by Target,

Species, and Area .......................

1990 ..............................................

1991 ..............................................

Shoreside Plant and Mothership Comparison by Target ....

1990 ..............................................

1991 ..............................................

Shoreside Plant and Mothership Comparison

by Target, Species, and Area ............

1990 ..............................................

1991 ..............................................

Discussion ..................................................

Conclusions and Recommendations .............................

Figures and Tables ..........................................

Citations ...................................................

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vii

List of Tables

Table

number

Gear type codes and target codes.......................

Catcher/processor catch comparisons by

region and gear, 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Catcher/processor catch comparisons by

region and gear, 1991.............................

Shoreside and mothership delivery catch

comparisons by region and gear, 1990.............

Shoreside and mothership delivery catch

comparisons by region and gear, 1991..............

Comparison between catcher/processor reports and

observer reports by gear and target in the

Bering Sea and Aleutian Islands Region, 1990......

Comparison between catcher/processor reports and

observer reports by gear and target in the

Gulf of Alaska Region, 1990.......................

Comparison between catcher/processor reports and

observer reports by gear and target in the

Bering Sea and Aleutian Islands Region, 1991......

Comparison between catcher/processor reports and

observer reports by gear and target in the

Gulf of Alaska Region; 1991.......................

Comparison between catcher/processor reports and

observer reports by NPFMC area, gear, and

target in the Bering Sea and Aleutian

Islands Region, 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison between catcher/processor reports and

observer reports by NPFMC area, gear, and

target in the Gulf of Alaska Region, 1990.........

Comparison between catcher/processor reports and

observer reports by NPFMC area, gear, and

target in the Bering Sea and Aleutian

Islands Region, lggl..............................

Comparison between catcher/processor reports and

observer reports by NPFMC area, gear, and

target in the Gulf of Alaska Region, 1991.........

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

gear and target in the Bering Sea and Aleutian

Islands Region, 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

gear and target in the Gulf of Alaska Region,

1990..............................................

Page

Preceding Page Blank 
viii

Table

number Page

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

gear and target in the Bering Sea and Aleutian

Islands Region, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

gear and target in the Gulf of Alaska Region,

1991... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

NPFMC area, gear, and target in the Bering Sea

-and Aleutian Islands Region, 1990.................

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

NPFMC area, gear, and target-in the Gulf of

Alaska Region, 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

NPFMC area, gear, and target in the Bering Sea

and Aleutian Islands Region, 1991.................

Comparison between processor reports and observer

reports for shoreside/mothership delivery by

NPFMC area, gear, and target in the Gulf of

Alaska Region, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total reported catch and total observed catch by

region and processor type, 1990...................

Total reported catch and total observed catch by

region and processor type, 1991...................
INTRODUCTION

In 1990 and 1991, the Alaska Fisheries Science Center (AFSC)

placed observers aboard U.S. fishing vessels engaged in fishing

activities in the Bering Sea and waters around the Aleutian

Islands (BSA) (Fig. 1) and the Gulf of Alaska (GOA) (Fig. 2).

The primary target of these vessels was a group of species

categorized as groundfish. A portion of the observer's sampling

duties require making an estimate of the vessel's total catch,

the weight of each species group that was retained for

processing, and the weight of each species group that was

discarded.

Observers were placed aboard the fishing vessels based upon

the vessel's overall length. Vessels longer than or equal to

125 feet in overall length were required to have an observer

aboard during all fishing operations (i.e., 100% coverage for the

setting and retrieving of gear). Vessels shorter than 125 feet

in overall length but at least 60 feet long were required to have

an observer aboard for 30% of the days (in each quarter) in which

the setting and retrieving of gear occurred (30% coverage).

Vessels shorter than 60 feet in overall length were only required

to carry an observer when it was mandated by the National Marine

Fisheries Service's (NMFS) Alaska Regional Director.

Catcher/processor vessels, motherships, and shoreside

processing plants were all required to send weekly reports of

product and discarded whole fish (WPRs) by species group-, gear

type used, and area fished to the NMFS Alaska Regional Office.

Observers monitoring the sorting of catches prior to processing

(and the accompanying discard of whole fish) sent weekly catch

reports to the NMFS AFSC. Observer reports contain information

detailing when and where fishing occurred, the gear type used,

the total weight of the catch, and the retained and discarded

amounts of each major species group. This report examines the

WPRs and compares them to the catch information collected by

observers monitoring these same operations.

Catcher/processor data were only used for those operations

when an observer was aboard the vessel the entire time the vessel

fished. In the BSA and GOA, most of the catcher/processor

fishing activities were carried out by vessels that were required

to have 100% observer coverage. Data collected by these

observers should be representative of the groundfish fishing

operations for catcher/processors in both areas.

The catcher boat/processing plant/mothership data used in

this report came from plants and motherships where an observer

sampled aboard at least one of the catcher boats delivering to

the plant or mothership during the week. Many of the vessels

involved in delivering catches for processing were only required

to have 30% observer coverage by quarter (both in the BSA and in

the GOA). The "30% coverage" class of vessels could choose when
2

they wanted their observers on board, so observer data from these

operations may not be representative of the plant and mothership

operations.

METHODS

Catcher/processor vessels, shoreside processing plants, and

motherships (including floating processors) send WPRs to the NMFS

Alaska Regional Office. These reports list the product weights

from each species during the week and the discard weights of each

species group. Standard product recovery rates for each species

and product have been jointly determined by industry and NMFS

scientists. Though the veracity of these rates have been

occasionally 'questioned, these rates are used to expand the

reported product weights to round weight of retained catch.

Catcher/processor vessels are required to report their own

discards. Plants and motherships are required to report any

discards made by their catcher boats as well as any additional

discards that occur after delivery. If a plant or mothership

doesn't accept a delivery or the haul is not landed, the catcher

vessel is responsible for reporting these catches as 100% discard

to the plant, which in turn is required to report this on their

weekly production report. However, observer reports have

documented several occasions when hauls have not been landed or

accepted but no discard amount was recorded.

Observers aboard catcher/processor vessels use one of two

primary methods to determine total, retained, and discarded

catch. In the first method, observers estimate the total catch

from the volume of fish in the vessel's storage bin or trawl codend. The amount of product and the species-specific product

recovery rates are used to determine retained catch, with the

difference between the total estimated catch and the calculated

retained catch being the estimated amount of discard. This

method accounts for discard which occurs both before and during

processing.

The second method uses the estimate of retained catch

(amount of product and product recovery rates) and the sampling

of the catch by observers for species and size composition to

estimate the discarded amount of catch and ultimately the total

catch. Product recovery rates are applied to the amount of

product to determine the retained catch. Percent species

composition by weight and length/weight data from observer

samples are used to calculate the discard-retained ratio of each

species. Applying this percentage to the amounts of retained

catch yields the amount of discard catch by species. Total catch

is then the sum of the retained and discard amounts. These

discarded catch calculations are based upon species composition
3

and fish lengths and weights. Any additional discard due to

other factors (e.g., spoilage due to length of processing time or

faulty equipment or processing, and loss due to fish sliding off

the conveyor belt) usually can not be quantified and is not

recorded. Therefore, this method only accounts for discard which

occurs prior to processing.

In method one, the accuracy of the discard amount is

dependant upon the accuracy of the total catch weight and the

accuracy of the product recovery rates used to determine retained

catch. In method two, the accuracy of all three amounts, total

catch, retained catch, and discard amount, are dependent upon the

accuracy of the product recovery rates. The only verifiable

weight in either method is the weight of the product on board;

thus, the accuracy of these methods depends upon the accuracy of

the product recovery rates.

Observers aboard catcher vessels that deliver sorted catch

to shoreside plants or floating processors have an even harder

time in determining the amount of catch discarded. Aboard many

catcher boats, observers generally have no established method of

estimating total catch at sea since the net is often brought

aboard in sections, or fish are pumped from the net, and the

observer frequently cannot sample all of the sections. Though

fish may be stored in a bin or holding tanks, the volume of fish

can not be determined because of no access to the bin or the

addition of unknown amounts of refrigerated sea water. When the

fish arrive at the plant or floating processor for processing,

the fish are off-loaded and the vessel (and the observer)

generally returns immediately to the fishing grounds. The

observer thus may not have the opportunity to monitor the final

sorting or the additional amounts of discard. For this reason,

observers are instructed to attribute everything delivered to the

plant or floating processor as being retained and the observers

aboard catcher boats have to use the second method described

above to calculate at-sea discard amounts. The shoreside plant

or floating processor provides the observer with the total

delivered weight (used by the observer as retained catch), and

the observer uses sampling data to determine the amount

discarded. If the observer is unable to sample at sea, 100% of

the catch is reported by the observer as being retained.

During early 1990, some observers only reported total catch

of each species and did not differentiate between retained and

discarded catch. These data have not been included in this

report because catch comparisons between the fishing vessels and

their observers was not possible.

In comparing observer reports to the expanded production

reports, observer data and WPRs for catcher/processor vessels

were pooled over time. Even though the comparisons for

catcher/processor vessels were made for vessels which had an
4

observer aboard, daily comparisons or even weekly comparisons

were not possible because processing reports are based on a

production day and observer reports are based on a calendar day.

Comparisons of reports from observers with shoreside plant

and mothership reported data can not be done in the same manner

as for catcher/processor vessels. For the catcher/processor

vessels, it was a one observer and one vessel comparison. For

the plants and motherships (especially floating processors), the

observed catch comes from individual vessels, but several

unobserved vessels may also deliver to the same plant or

mothership during the week, and these unobserved vessels may have

different targets than the observed vessels. Each observed

vessel has a weekly target assigned to it, based on observed

catch, area, and gear. Each plant or mothership has a single

weekly target assigned to it for each area and gear, based on its

WPR, regardless of the number of catcher vessels. In this

report, a comparison was made only when the observed fishing

vessel had the same target for the week, area, and gear, as the

plant or mothership (including floating processors) to which it

delivered.

In comparing observed versus reported catch for catcher/

processors, data were only used when the observer was aboard the

vessel the entire time the vessel fished and reported the same

targets and areas. Because this is a one-to-one comparison,

retained catch amounts and discard amounts should each be quite

similar. For processing plants (including motherships and

floating processors), it was not always a one-to-one comparison.

Frequently, only a portion of the catcher vessels were observed.

Thus, the absolute amounts should not be similar, but the ratio

of discard to retained catch should be similar.

Table 1 provides definitions of the gear type codes and

target codes referred to in this report.

RESULTS

Catcher/Processor Overall Comparison

The retained, discarded, and total catches of groundfish

reported in the WPRs and from observers are shown for

catcher/processors by gear type for the BSA and the GOA Regions

for 1990 in Table 2 and for 1991 in Table 3. As previously

stated, the catches shown in these tables are only for those

vessels and time periods when an observer was aboard for the

entire period and was sampling for discards. Percentage of the

catches retained and discarded are also provided in these tables.
5

Both bottom trawl and pelagic trawl gear were used in the

BSA groundfish fishery in 1990 and 1991. In the bottom trawl

fishery, the percentage of catch retained and discarded in the

WPRs and reported by observers were similar within each year.

However, the percentage of catch discarded increased from about

28% of the catch in 1990 to 40% of the catch in 1991. The

increased discard was due primarily to a greatly reduced walleye

pollock (Theragra chalogramma) fishery in 1991, an increased

discard rate in the pollock fishery that did occur, and a

substantial increase in total catch in the flatfish fishery

(combined targets of rock sole, [Pleuronectes bilineatus],

arrowtooth flounder [Atheresthes stomias] and Kamchatka flounder

[A. evermanni] and other flatfish) along with its high discard

rate. Comparison of the total amounts of catch reported in the

WPRs with observer reports shows that the catch reported by

observers in 1990 was about 24% greater than that reported by the

vessels. In 1991, observers reported the total catch taken in

the bottom trawl fishery to be about 9% greater than that

reported by the vessels.

The percentages of catch reported as discarded and retained

by the vessels and the observers from vessels using pelagic trawl

gear were similar both within and between years. In 1990 and

1991, 92-93% of the catch was retained, while 7-8% was discarded.

The pollock fishery accounts for the greatest part of the fishery

conducted with pelagic trawls. In 1990, the total catch in the

pelagic trawl fishery reported by observers was 44% greater than

the amount reported by the observed vessels. In 1991, the

difference decreased, but the catch reported by observers was

still 26% greater than that reported by the observed vessels.

As in the BSA, fisheries are conducted in the GGA with both

bottom trawls and pelagic trawls. In the bottom trawl fisheries,

the percentage of catch retained and discarded in the WPRs and

the observer's reports were similar for each year. However, the

percentage of discard decreased from about 53% of the catch in

1990 to about 40% of the catch in 1991. This decrease was due to

a decreased discard rate in the rockfish fishery and a sharp

reduction in total catch for two fisheries that had high rates of

discard (sablefish [Anonlonoma fimbria] and miscellaneous fish).

In 1990, the total bottom trawl catch reported by observers

exceeded their vessel's reports by 11%. In 1991, this difference

was only 4%.

Data from the GOA pelagic trawl fisheries shows a

substantial reduction in the discard rate from 1990 to 1991. In

both 1990 and 1991, the catches came almost exclusively from the

pollock fisheries. In 1990, however, the WPRs showed a discard

rate of 16.8% and the observer's reports showed a discard rate of

26.2%. In 1991, both the WPRs and the observer's reports showed

a discard rate of 4.0%. In 1990, the observer's reports of total
6

pelagic trawl catch exceeded their vessel's reports by only 1.6%.

In 1991, this difference increased to 16.1%.

The 1990 BSA pot fishery was very small, yielding only about

1,000 metric tons (t) of total catch. The WPRs showed a discard

rate of only 2.5%; the observed discard rate was 6.6%. All of

the catch came from vessels targeting Pacific cod (Gadus

(macrocephalus) In 1991, this fishery expanded to over 3,000 t.

The observed discard rate shrank to 4.63, but the vessel's

reported discard rate increased to 12.2%. As in 1990, all of the

catch came from vessels targeting Pacific cod. The GOA pot

fishery accounted for a small portion of the total GOA fishery in

both 1990 and 1991.

In the 1990 BSA longline fishery, WPRs showed a discard rate

(8.1%) that was 4.7 percentage points lower than that reported by

the observers (12.8%). In 1991, both sets of reports showed a

2.5 percentage point increase in the discard rate when compared

to 1990. This was due primarily to an increased catch of Pacific

cod and its associated higher discard rate. In 1990, the total

longline catch reported by observers was 9% greater than the

amount reported by their vessels. In 1991, this difference was

21%.

In the 1990 GOA longline fisheries, observer's reports of

retained catch were within 100 t of their vessel's reports of

retained catch. However, the observer's reports of discard

exceeded their vessel's discard reports by over 1,300 t. The

observed discard rate for 1990 was 52.13, while the vessel's

reported discard rate was 21.7%. In 1991, discard rates

decreased substantially. Observer's reports of retained and

discarded catch were each less than 100 t greater than their

vessel's reports, yielding an observed discard rate of 5.4%

versus a WPR discard rate of 3.3%. These reduced discard rates

occurred for both the Pacific cod and the sablefish fisheries.

In 1990, the observer's reports of total catch aboard longline

vessels exceeded their vessel's reports by 55%.

difference was only 5%.

In 1991, this

Shoreside Plant and Mothership Overall Comparison

Tables 4 and 5 provide the retained, discarded, and total

catches of groundfish reported in the WPRs and from observers for

shoreside plant and mothership operations in 1990 and 1991.

These data are aggregated by gear type of the delivering catcher

vessels and by region. These data are for the plants and

motherships and time periods for which associated observer catch

reports exist. Percentage of the catches retained and discarded

are also provided in these tables.
7

Both bottom trawl and pelagic trawl gear were used by

catcher vessels in the BSA groundfish fishery in 1990 and 1991.

In the 1990 bottom trawl fishery, the observed amount of discard

was about 300 t less than the amount reported by the processors,

but the observed amount of retained catch was 6,200 t less than

the reported amount. The -observed discard rate was 26.8% but the

WPRs showed a discard rate of only 17.2%. In 1991, the observed

amount of discard in the bottom trawl fishery was 2,300 t less

than the processor report and the observed retained was almost

20,000 t less than the processors reported. This yielded an

observed discard rate of 29.6% and a processor reported discard

rate of 20.9%. In 1990, the bottom trawl fishery targeted almost

exclusively on Pacific cod. In 1991, the fishery with the large

discrepancy in discard rates was also the Pacific cod fishery.

The percentages of catch reported as discarded and retained

by the plants and the observers from vessels using pelagic trawl

gear were similar both within and between years. In all cases,

the discard rate was between 1.4% and 2.4%. However, in 1990,

the observers' discard amount was over 100 t greater than the

processors' reported amount, yet the processors' retained catch

was almost 65,000 t greater than the observed retained amount.

The processor discard rate was 1.4% and the observed discard rate

was 2.4%.

Fisheries conducted in the GDA also used both bottom trawls

and pelagic trawls. In the bottom trawl fisheries, the 1990

observer report of discard was similar to that reported by the

processors (about 500 t less), but the processors’ report of

retained catch was 3.5 times the amount reported by the

observers. The processor discard rate was 14.2% and the observed

discard rate was 34.8%. Discard rates went down in 1991. The

processor discard rate was 11.3% and the observed discard rate

was 16.5%. This decrease was due to a decreased discard rate in

the flatfish fishery in 1990, and the combined deep-water

flatfish and shallow-water flatfish fisheries in 1991 and an

increase in the total catch of the Pacific cod fishery and its

associated lower discard rate.

Data from the GOA pelagic trawl fisheries shows a 0.8%

observed discard rate and a 2.3% processor reported discard rate

in 1990. In 1991, discard rates went up. The observed discard

rate was 2.7% and the processor reported discard rate was 2.8%.

In both years, pollock was the main target for the pelagic trawl

fisheries.

No catcher vessels using pot gear were observed in the BSA

in 1990 or 1991. In 1990, in the GOA, catcher vessels using pot

gear reported less than 1,000 t of groundfish and had a discard

rate of 0.3%. Observer reports from these vessels showed a

discard rate of 8.2%. All of the catch came from vessels

targeting Pacific cod. In 1991, observed catcher vessels using
8

pot gear reported over 2,400 t of groundfish catch. The observed

discard rate shrank to 1.3% and the processors', reported discard

rate was 0.1%. As in 1990, all of the observed catch came from

vessels targeting Pacific cod.

In the BSA, catch by observed catcher vessels using longline

gear was inconsequential in 1990 and was non-existent in 1991.

In the GOA, observers reported retained catch that was only about

one-sixth of that reported by their processors, but reported more

than twice as much discard. The observed discard rate was 38.0%

and the processor reported discard rate was only 4.6%. In 1991,

the observed discard rate fell to 14.2% and the processor

reported discard rate was 4.7%. In both 1990 and 1991,

essentially all of the catch came from the sablefish fishery.

Comparison of Total Reported Catch to Total Observed Catch

Catcher/Processor Comparison by Target

1990--In 1990, in the BSA bottom trawl fishery, the observerreported groundfish catches exceeded their vessels' reports by

over 52,000 t (42,000 t retained and 10,000 t discarded).

Table 6 shows that most of this difference came from vessels

targeting pollock (targets B and P combined) (28,000 t retained

and 5,000 t discarded), flatfish (target F) (5,000 t retained and

1,500 t discarded), and miscellaneous fish (target 0, which

contains Pacific cod and any other species not included in the

target categories defined in Table 1) (8,000 t retained and

2,000 t discard). Vessel reports from the rest of the target

fisheries closely matched their observer reports (except for the

Greenland turbot (Reinhardtius hippoglossoides) fishery, where

the observers' discard amount exceeded the vessels' reported

amount by 900 t). The pollock target fishery was the only one

with a discard rate less than 20%.

In the pelagic trawl fishery, observed groundfish catches

exceeded the observed vessels' reports by 290,000 t. Reports

coming from vessels with almost pure ( ≥ 95%) pollock catches

(target P) accounted for almost all (288,000 t) of the

difference. Vessels targeting flatfish and miscellaneous fish

(generally containing large amounts of Pacific cod) had much

higher discard rates than those targeting pollock. For

longliners, observers reported a 2,400 t difference in discard

amounts. Most of this (2,200 t) came from catches that were

predominantly Pacific cod.

In 1990, in the GCA bottom trawl fishery, the observerreported groundfish catches exceeded their vessels' reports by

4,700 t (2,400 t retained and 2,300 t discarded). The

differences were evenly spread out over all the various target

fisheries (Table 7). All of the target fisheries had discard
9

rates exceeding 20%. Observed and WPR discard rates compared

closely in all fisheries except in the small pollock fishery.

In the small pelagic trawl fishery, almost all of the catch

was attributed to the pollock fishery. Observed discard rates

exceeded WPR discard rates by almost 10 percentage points. In

the longline fishery, sablefish was the primary target

(target S). Observed discard amounts exceeded the discard in

the WPRs by 1,300 t.

1991--In 1991, in the BSA bottom trawl fishery (Table 8), the

19,000 t difference (13,000 t retained and 6,000 t discarded)

between observed and reported total catches were spread out

primarily among the pollock (4,000 t retained and 1,000 t

discarded), Pacific cod (target C) (2,500 t retained and 700 t

discarded), flatfish (6,400 t retained and 300 t discarded), and

rock sole (target R) (2,000 t retained and 2,500 t discarded)

fisheries (Table 8). Observed discard rates less than 20%

occurred only for the Atka mackerel (target A) and pure ( 3 95%)

pollock fisheries.

In the pelagic trawl fishery, the observed catch exceeded

the reported catch by 150,000 t (116,000 t retained and 34,000 t

discarded). The pollock fishery accounted for essentially all of

the difference. Only the Pacific cod fishery had a discard rate

higher than 20%.

In the longline fishery, the Pacific cod fishery accounted

for practically all of the catch. In this fishery, the observed

catch exceeded the vessels' reported catch by almost 12,000 t

(7,400 t retained and 4,300 t discarded).

In 1991, in the GGA bottom trawl fishery, the difference

between the vessel-reported and the observer-reported catches was

only 1,300 t (Table 9). This difference was spread out over all

the various target fisheries. The only observed discard rate

less than 20% was in the Pacific cod fishery. Observed and WPR

discard rates compared closely in all target fisheries.

In the pelagic trawl fishery, the only target was pollock,

and the observed groundfish catch was 2,100 t (16.1%) larger than

the reported groundfish catch. The observed and reported discard

rate was 4.0%. In the longline fishery, the observed and

reported catches were about the same.

Catcher/Processor Comparison by Target Species. and Area

Tables 10 through 13 compare the vessels reported catches

of pollock, Pacific cod, and the flatfish complex (except

arrowtooth flounder, Kamchatka flounder, Greenland turbot and

Pacific halibut [Hippoglossus stenolepis]), both retained and
10

discarded, with the observers' reports. For longline vessels,

the retained and discarded catches of sablefish were compared in

place of the flatfish complex.

1990--In the 1990 BSA bottom trawl fishery (Table 10), observers

reported that 23.7% (32,330.7 t) of the pollock catch was

discarded, 13.0% (5,345.0 t) of the Pacific cod catch was

discarded, and 43.3% (13,142.7 t) of the flatfish catch was

discarded. WPR discard rates for these species were 27.9%

(27,783.5 t), 9.2% (2,883.4 t),

respectively.

and 50.9% (14,501.l t),

The largest amounts of pollock discards occurred

in North Pacific Fisheries Management Council area 511 (all

targets) (11,686.4 t observed), in the rockfish fishery in area

540 (3,218.5 t observed), in the pollock fishery in area 521

(2,797.7 t observed), and in the miscellaneous fishery in area

517 (2,664.1 t observed). The largest amounts of Pacific cod

discards occurred in the miscellaneous fisheries in area 517

(972.2 t observed) and 521 (509.3 t observed) and in the pollock

fishery in area 521 (553.4 t observed). The largest amounts of

flatfish discards occurred in the flatfish fisheries in area 511

(2,215.0 t observed) and 514 (3,114.6 t observed).

In the pelagic trawl fisheries, observer reports showed

pollock, Pacific cod, and flatfish discard rates of 6.7%

(63,102.8 t), 63.3% (4,791.2 t),

respectively.

and 77.6% (2,181.8 t),

discard rates.

Vessels using pelagic gear reported similar

For all three species, the largest amount of

catch and the largest amount of discard came in the pollock

fishery (target P) in area 521 (observed 486,850.6 t retained and

35,874.9 t discarded).

Pot vessels fished primarily in areas 511, 517, and 521.

They kept all of-their Pacific cod and discarded essentially all

of the other species caught.

in areas 517, 521, and 522.

Longline vessels fished primarily

They discarded practically all of

the pollock caught, and almost no Pacific cod or sablefish.

In the 1990 GOA bottom trawl fishery (Table 11), observers

reported that 56.8% (2,889.5 t) of the pollock catch was

discarded, 28.5% (1,125.8 t) of the Pacific cod were discarded,

and 51.3% (4,335.0 t) of the flatfish were discarded. Vessel

reports of discard were not as high, 54.3% (2,213.4 t), 22.8%

(611.0 t), and 40.5% (2,056.3 t), respectively. Retained catches

of pollock occurred primarily in the pollock fisheries in areas

610 (577.2 t observed) and 630 (843.8 t observed). Most of the

pollock caught in the non-pollock fisheries were discarded. In

the pollock fishery in area 630, the observers reported a pollock

discard rate of 49.3% (821.9 t); the WPRs showed a pollock

discard rate of 0.5% (4.0 t). Pacific cod were caught primarily

by the miscellaneous fishery in areas 610 (1,847.3 t observed)

and 620 (586.9 t observed). About 28% (517.0 t observed, 368.7 t

on the WPR) of the Pacific cod caught in the miscellaneous
11

fishery in area 610 were discarded; almost none of the Pacific

cod were discarded in the miscellaneous fishery in area 620.

Most of the flatfish catch came from the flatfish fisheries in

areas 610 (1,136.3 t observed) and 620 (4,030.5 t observed). In

the flatfish fishery in area 610, retention of flatfish was

almost 100%. In the flatfish fishery in area 620, the observed

discard rate was 50.3% (2,025.8 t) and the WPR discard rate was

19.8% (376.1 t). Most of the flatfish caught in the non-flatfish

fisheries were discarded.

For pelagic trawlers, the observed pollock discard rate was

25.2% (1,844.7 t), the vessel-reported pollock discard rate was

2.9% (180.7 t), and there were negligible amounts of Pacific cod

and flatfish caught. For longliners, essentially all of the

Pacific cod and sablefish were retained, and negligible amounts

of pollock were caught.

1991--In the 1991 BSA bottom trawl fishery (Table 12), observers

reported a discard rate of 66.8% (28,127.0 t) for pollock, 14.0%

(4,414.0 t) for Pacific cod, and 38.5% (48,155.4 t) for flatfish.

The vessel reports of discard were 73.1% (25,976.g t), 10.5%

(2,587.0 t), and 40.3% (48,050.7 t), respectively. Catches of

pollock occurred primarily in areas 511 (34.2% of the observed

catch) and 521 (23.5% of the observed- catch). Most of the

pollock caught in area 511 was discarded; most of the area 521

pollock catch was retained. Large amounts of pollock discard

also occurred in the rock sole fisheries in areas 513 (1,147.5 t

observed) and 516 (1,318.1 t observed), and in the flatfish

fisheries in areas 513 (1,854.2 t observed) and 514 (3,591.4 t

observed). Retention of Pacific cod occurred primarily in the

pollock fisheries (target B only) in areas 511 (2,347.0 t

observed) and 521 (1,510.6 t observed), in the flatfish fishery

in area 514 (1,885.3 t observed), and in the Pacific cod

fisheries in areas 517 (2,427.4 t observed) and 521 (9,162.6 t

observed). Large amounts of Pacific cod discard occurred in the

rock sole fishery in 511 (6,108.8 t observed) and in the flatfish

fishery in area 514 (3,591.4 t observed). Most of the retained

and discarded amounts of flatfish occurred in the flatfish and

rock sole fisheries in 511 (observed 6,876.7 t retained and

6,514.6 t discarded), 513 (observed 11,743.6 t retained and

7,841.6 t discarded), 514 (observed 49,437.4 t retained and

22,995.l t discarded), and 516 (observed 3,536.9 t retained and

5,761.0 t discarded).

In the pelagic trawl fisheries, observed discard rates of

pollock, Pacific cod, and flatfish were 8.1% (56,573.0 t), 31.6%

(4,383.6 t), and 90.4% (3,127.8 t), respectively. WPR discard

rates for these same species were 4.5% (25,194.8 t), 31.4%

(2,558.5 t), and 97.4% (3,033.8 t). Vessels targeting pollock

were responsible for most of the pollock and Pacific cod discard

(observed 56,040.4 t and 3,823.6 t, respectively). Vessels

targeting Pacific cod retained most of the Pacific cod which they
12

caught. All vessels discarded almost all of the flatfish that

were caught.

Pot vessels caught almost exclusively Pacific cod, and

discarded almost everything else that they caught. The observed

Pacific cod discard rate was 1.1% (36.7 t). The WPR discard rate

was 9.4% (299.9 t). For longliners, most of the pollock were

discarded, and most of the Pacific cod and sablefish were

retained. Observed discard rates for Pacific cod and sablefish

were 2.7% (1,529.4 t) and 2.3% (10.6 t), respectively. WPR rates

for these species were 0.1% (33.0 t) and 0.5% (2.9 t).

In the 1991 GOA bottom trawl fishery (Table 13), observers

reported a pollock discard rate of 80.7% (2,528.3 t), a Pacific

cod discard rate of 7.7% (373.5 t), and a flatfish discard rate

of 21.9% (1,020.1 t). The vessel-reported discard rates were

similar (except that the Pacific cod discard rate was 4.0%

(196.6 t]).

In the pelagic trawl pollock fishery, observers reported a

pollock discard rate of 2.1% (315.6 t). Vessels reported a

pollock discard rate of 2.5% (323.3 t). Minimum amounts of

Pacific cod and flatfish were caught. Except for 0.2 t of

discarded flatfish, pot vessels caught and retained only Pacific

cod. For longliners, the pollock catch was minimal and

essentially all of the Pacific cod and sablefish were retained.

Shoreside Plant and Mothership Comparison by Target

1990--BSA bottom trawl results for 1990 (Table 14) show that the

total observed tonnage accounted for 57% of the total amount

reported by the observed plants and motherships. However, the

observers' reports of the discard tonnage accounted for 89.1% of

the reported discard amount. In the small pollock fishery,

observed and reported retained catch amounts were about the same,

but the observed amount of discard was twice that reported in the

WPRs. Most of the groundfish catch came from vessels in the

miscellaneous fishery (primarily Pacific cod). The observed

discard rate was 27.1%; the WPR rate was 17.3%.

For pelagic trawlers, the total observed tonnage accounted

for only 61% of the catch reported by the observed plants and

motherships, but the observed discard amount exceeded the WPR

discard amount by 6.1%. Thus, the reported discard rate was only

1.43, while the observed discard rate was 2.4%. In the pure

(2 95%) pollock fishery, the reported catch exceeded the observed

catch by 63,500 t (63.6%), yet the discard amount was the same.

For longline vessels, the observed total catch exceeded the

reported total catch by 10.5%. The observed discard rate was

62.3% (321.1 t); the plant/mothership reported discard rate was
13

only 0.3% (1.4 t). The observed discard was primarily Greenland

turbot. No catch of Greenland turbot (retained or discarded)

showed up on the WPRs at all. Sablefish was the primary target

of the longline fleet.

In the GOA, the 1990 observer reports accounted for only

34.8% of the total catch reported for bottom trawl vessels, but

the observer reports of discard accounted for 85.6% of the total

discard amount reported by their plants and motherships (Table

15). In the miscellaneous fishery (primarily Pacific cod),

observed retained fish reports were 73.3% less than the WPRs, but

the discard amount was 23.4% higher. Overall, the observed

discard rate was 34.8%; the plant/mothership reported discard

rate was 14.2%.

Observers aboard vessels using pelagic gear reported a total

catch that was 61.6% lower than the amount reported by the

plants/motherships. Observers' reports of retained catch were

61.0% less than that reported by the plants/motherships and the

observed amount of discard was 87.1% lower than that reported by

the plants/motherships. The observed discard rate was 0.8%, and

the reported discard rate was 2.3%.

Observers aboard longliners reported 74.7% less total catch

than the comparable plants/motherships reported. Observers

reported the retained catch to be 83.5% less than that reported

by the plants/motherships, but the observed amount of discard

exceeded that reported in the WPRs by 111.2%. The observed

discard rate was 38.0%, and the reported discard rate was 4.6%.

Sablefish was the primary target of the longline fleet.

Observers reported that most of the discards were non-allocated

species (prohibited species and other species not receiving a

quota), a species group category not included in the WPRs.

1991--In the 1991 bottom trawl fishery in the BSA, the WPR

discard rates exceeded the observed discard rates in the pollock,

rock sole, and flatfish fisheries (Table 16). However, in the

large Pacific cod fishery, the observed discard rate was 27.4%

and the WPR rate was 15.2%.

In the pelagic trawl fishery, observers also reported higher

discard rates in the Pacific cod fishery than were shown in the

WPR. In the much larger pollock fishery, however, the WPR

discard rate was 1.6% versus the observed discard rate of 1.2%.

In the pot and longline fisheries, there was minimal catch

and negligible amounts of discard.

For the GOA, observers aboard bottom trawlers in 1991 (Table

17) reported a total catch that was 62.5% lower than the plants

and motherships reported. The observed retained catch was 64.7%

lower than that reported in the WPRs, and the discard amount was
14

45.3% lower than the reported discard amount. For each fishery

except a small pure pollock fishery, the observed discard rate

was higher than the WPR discard rate.

For vessels using pelagic gear, the reported and observed

discard rates were similar in the pollock fishery. However, in

the very small Pacific cod fishery, the WPRs showed no discard

while observers reported a discard rate of nearly 50%.

Observed pot vessels retained most all of their catch. WPRs

from pot vessel deliveries showed the same results.

Observers aboard longline vessels reported 78.1% less total

catch than did the comparable plants/motherships. The observed

retained catch was 80.3% less than the plants/motherships, but

the discard amount was only 33.5% less than the reported discard

amount. The observed discard rate was 14.2%, the reported

discard rate was 4.7%. Sablefish was the predominant target for

the longline vessels.

Shoreside Plant and Mothershin Comparison by Target Species and

Area

Tables 18-21 compare the plants, and motherships' reported

catches of pollock, Pacific cod, and the flatfish complex (except

arrowtooth flounder, Greenland turbot, and Pacific halibut), both

retained and discarded, with the observer's reports. For

longline vessels, the retained and discarded catches of sablefish

were compared in place of the flatfish complex.

1990--In the 1990 BSA bottom trawl fishery (Table 18), observers

reported that 69.6% (1,035.7 t) of the pollock catch was

discarded, 1.5% (89.2 t) of the Pacific cod catch was discarded,

and 92.3% (583.3 t) of the flatfish catch was discarded. The WPR

discard rates were 78.9% (1,412.2 t), 2.5% (311.2 t), and 99.0%

(612.0 t), respectively. Vessels targeting Pacific cod discarded

minimal amounts of Pacific cod, but most of everything else.

Vessels targeting pollock discarded essentially no pollock, but

discarded most of the other species.

For pelagic trawlers, the observer reports showed discard

rates of pollock, Pacific cod, and flatfish as 1.5% (1,477.6 t),

10.6% (41.9 t), and 43.3% (100.7 t), respectively.- The WPR

discard rates were 1.0% (1,600.0 t), 6.8% (68.3 t), and 14.2%

(50.3 t), respectively. These vessels targeted primarily on

pollock, and caught little else. Most of the Pacific cod were

caught by vessels targeting Pacific cod (538.6 t reported,

246.1 t observed). These vessels retained only Pacific cod.

The few longline vessels that operated targeted primarily on

sablefish. Essentially no discard occurred.
15

In the 1990 GOA bottom trawl fishery (Table 19), observers

reported that 64.9% (466.6 t) of the pollock catch was discarded,

0.7% (38.6 t) of the Pacific cod were discarded, and 53.1%

(620.6 t) of the flatfish were discarded. Plant and mothership

reports of discard were generally lower, 43.0% (630.1 t), 0.8%

(172.6 t), and 40.9% (706.8 t), respectively. Most of the catch

and discard occurred aboard vessels targeting miscellaneous fish

(primarily Pacific cod) in areas 610 and 630.

For pelagic trawlers, the observed pollock discard rate was

0.4% and the WPR pollock discard rate was 1.6%. Observers

reported negligible amounts of Pacific cod and flatfish caught.

Plants/motherships reported 110 t of Pacific cod and 112 t of

flatfish, essentially all of it retained (retention rate of 98.9%

for Pacific cod and 97.0% for flatfish).

Pot vessels caught almost exclusively Pacific cod and kept

it all. For longliners, essentially all of the catch was

retained sablefish. Very little discard occurred.

1991--In the 1991 BSA bottom trawl fishery (Table 20), observers

reported a discard rate of 79.0% (3,373.5 t) for pollock, 3.9%

(438.4 t) for Pacific cod, and 32.6% (3,228.5 t) for flatfish.

The plant/mothership reports of discard were 76.2% (3,983.3 t),

1.9% (570.4 t), and 35.3% (4,547.5 t), respectively. Most of the

pollock and Pacific cod discards occurred in the Pacific cod

fishery in area 517 (reported discard of 2,719.8 t of pollock and

472.9 t of Pacific cod). Most of the flatfish discards occurred

in the flatfish fisheries in area 514 (2,545.2 t reported). In

the roundfish fisheries, the observed discard rates were much

higher than those in the WPRs. In the flatfish fisheries, WPR

discard rates exceeded the observed discard rates.

For pelagic trawlers, observers reported discard rates of

1.7% (4,459.0 t), 8.2% (582.3), and 75.1% (643.7 t), for pollock,

Pacific cod, and flatfish, respectively. The plant/mothershipreported discard rates were 1.7% (8,222.0 t), 5.4% (490.3 t), and

56.1% (585.5 t). Most of the differences occurred in the Pacific

cod fishery in area 517.

Pot and longline vessels caught primarily Pacific cod, and

discard amounts of the three species reviewed was insignificant.

In the GOA bottom trawl fishery (Table 21), observers

reported a pollock discard rate of 50.6% (597.4 t), a Pacific cod

discard rate of 1.5% (147.6 t), and a flatfish discard rate of

31.9% (477.8 t). The WPR rates were 51.2%,(1,540.6 t), 0.6%

(179.7 t), and 22.9% (959.9 t), respectively. Most of the

Pacific cod catch (23,495.3 t for the WPRs) and most of the

discards for all three species (2,144.9 t combined for the WPRs)

occurred in the Pacific cod fishery in areas 610 and 630. In
16

both of these areas, the observed discard rates were higher than

for the WPRs.

For pelagic trawlers, observers reported discard rates for

pollock, Pacific cod, and flatfish, of 2.3% (530.9 t), 9.1%

(9.5 t), and 49.0% (7.4 t), respectively. The plants/motherships

reported discard rates of 2.6% (1,398.9 t), 0.2% (2.3 t), and

30.2% (11.4 t). A Pacific cod fishery in area 610 accounted for

most of the Pacific cod catch (1,071.8 t for the WPRs). WPRs in

this fishery reported no discards, but the minimal observer

coverage that occurred reported discards for all three species

groups. Minimum amounts of flatfish were caught by trawlers

using pelagic gear.

Pot vessels caught and retained primarily Pacific cod. On

longline vessels, essentially all of the sablefish were retained

and catches of pollock and Pacific cod were minimal.

DISCUSSION

In making comparisons of observed versus reported catch for

catcher/processors, data were only used for cases in which the

observer was aboard the vessel the entire time the vessel fished.

It was expected that the retained catch amounts and the discard

amounts would each be quite similar. For processing plants

(including motherships and floating processors), it was not

always a one-to-one comparison. Frequently, only a portion of

the catcher vessels were observed. Thus, it was not expected

that the absolute amounts would be similar, but that the ratio of

discard to retained catch would be similar. The expected results

did not occur for either catcher/processors or processing plants.

The reasons for this are not altogether clear.

Observer sampling for discards is often difficult. Crew

members frequently intercept unwanted species prior to arrival in

the factory, and these fish may be discarded without the

observer's knowledge. Once in the factory, discard may occur at

several places at once, throughout production, and it is

sometimes difficult for observers to monitor all of the

discarding that takes place.

Aboard catcher/processors and motherships that receive

unsorted catch, discard amounts for totally non-utilized species

in the catch are more easily determined than discard amounts for

the species which are utilized. For totally non-utilized

species, the total catch of the species equals the total amount

discarded. If the observer can determine the species' total

catch, then the discard amount is known. For utilized species,

determination of discarded amounts is complicated by such factors
17

as variation from haul to haul of the size of fish used,

limitations on the processing capacity of the vessel, and

differences in how and what each crew member sorts during the

processing of the catch.

Fishery observers use two main methods to determine

retained, discarded, and total catch. In the first method, total

catch and retained catch are calculated independently, and

discard weight is attained through subtraction. The accuracy of

the discard is dependent on the accuracy of the total catch

weight and the retained catch weight estimates. In the second

method, retained catch is calculated using product recovery rates

and discard is calculated using species composition samples,

length-weight samples, and knowledge of fish size requirements

for processing, to determine a discard to retained ratio.

Product recovery rates are an integral factor in both

methods, and the discard to retained ratio in method two is

imprecise in that it only accounts for pre-processing discard.

Thus, method one is the preferred method for calculating discard.

However, study of the observer's sampling reports shows that

observers are frequently unable to use volumetric calculations to

get good estimates of total catch. Thus, aboard

catcher/processors and motherships, method two is used more than

half of the time. Method two does allow a fairly good discard to

retained ratio to be determined for these vessels, but doesn't

address the fish loss that occurs during processing.

For catcher vessels that deliver sorted catch to plants or

floating processors, discard rates are more questionable.

Observers aboard these vessels have to use method two to

calculate discard, and frequently have an incomplete view of

retained catch. For vessels targeting on species other than pure

( 3 95%) pollock, most of the catch is sorted at sea, and a fairly

good accounting can be made of the pre-delivery discards. For

pure ( 3 95%) pollock tows, however, all pollock are typically

retained by the vessel (and counted as retained by the observer),

regardless of size. Once on shore, the pollock are then sized

and small pollock are sent to a fish meal plant. These pollock

are labelled as retained by the reporting plant (except in

Kodiak, where they are reported as discard) and are either turned

into meal or are discarded by the meal plant. Typically, WPRs do

not reflect discard by the meal plants.

The discard amounts reported by observers aboard

catcher/processors appear to come closest to being an accurate

indication of discard. Most observers aboard catcher/processors

using trawl gear reported a discard rate similar to that reported

by the vessels, and the observed discard amount is usually

calculated as a percentage of retained catch. Conversely,

observer's estimates for the catcher vessels underestimate the

total amount of discard. Observers report all fish delivered to
18

the plant or mothership as being retained, even though a portion

of these fish will later be discarded.

The above paragraph brings up an interesting point. Plant

WPRs and mothership WPRs are required to include all of their own

discard as well as all of the at-sea discard of their catcher

vessels. Observers report all delivered fish as retained and

only report at-sea discards. Additionally, observers are not on

all of the vessels delivering to the plants and motherships.

Thus, the discards reported on these WPRs should always exceed

the observed amounts, and should usually exceed the observed

discard percentages. This is not happening. Instead, an

unlikely occurrence is being presented as the norm. The reported

retained amounts greatly exceed the observed retained amounts

(due to large numbers of unobserved vessels), but the reported

discard amounts (from all vessels) and the observed discard

amounts are quite similar. In many cases, the observed at-sea

discard is greater than the reported total discard, at times

exceeding it by 10-20 percentage points.

The WPRs appear to underestimate the amount of

plant/mothership discards, but the magnitude of this

underestimation is unclear. For these reasons, it is not

appropriate to compare discard rates from the catcher/processor

fleet with discard rates from the catcher vessels.

A major concern throughout the data reviewed, is the

discrepancy between observed retained catch and the processor

reports of retained catch. The data presented in Table 2 show

that the observed retained catch in the 1990 BSA

catcher/processor fleet exceeded the retained catch reported by

the same vessels by 37.5%. Observed retained catch in the 1991

BSA catcher/processor fleet (Table 3) exceeded the reported

retained catch by 19.0%. For the GOA catcher/processor fleet,

the observed retained catch exceeded the reported retained catch

by 6.2% in 1990, and the 1991 observed retained catch exceeded

the reported retained catch by 10.1%. In most cases, product

recovery rates are being used to determine the vessel's, the

plant's, and the observer's report of total retained catch. WPRs

give the product weights, and product recovery rates are used to

convert product weight to round weight. The product recovery

rates have been generated from observer reports from past years

(Berger and Hare 1988), from NMFS and Alaska Department of Fish

and Game scientists (Low et al. 1989), and from information and

comments from industry. However, the rates being used are annual

average rates, and the appropriateness of several of them are

still being questioned by industry (the surimi rate is one of

those in question, and the largest discrepancy between observer

and catcher/processor reports appears in the mid-water pollock

fishery where the primary product is surimi). Observers are

instructed to use the ship's tested product recovery rates

whenever possible to determine the retained groundfish catch.
19

Thus, if the vessels' actual product recovery rates are lower

than those being used by the NMFS to convert reported product to

round weight, then the observed round weight will be higher than

that calculated from the vessels' reports.

Five possible scenarios could cause the differences between

observed and reported retained catch. One, the vessels are

under-reporting the amounts of product actually being produced.

Two, observers are being given an inflated accounting of product

by the vessels (probably not the cause because observers

frequently count cases of products aboard the vessels or use

other means to get their own measure of product). Three,

inaccuracies in observer sampling are leading to erroneous

results. Four, observers are using actual vessel product

recovery rates which are lower than the NMFS standard rate to

convert product weight to round weight. Five, the data bases

themselves are still not free from error. Checking of the data

bases continues, and some errors are still being found. With the

WPRs, it is generally missing data (which would lead to lower

reported total catch amounts. With the observer data, errors

tend to be weights that are too high (leading to higher total

catch amounts). Overall, these errors should have a minimum

effect, but some differences will result. Additionally, in 1990,

the observer discard data included non-allocated species.

However, this had negligible results in all comparisons except in

the Gulf of Alaska longline fishery.

For plants, motherships, and floating processors, the

problem is more complex. WPRs come from the plants, motherships,

and floating processors rather than from the catcher vessels, and

observers are not on all catcher vessels making deliveries.

Thus, there is no direct one-to-one vessel and observer report as

there is for most of the catcher/processors, so direct

comparisons of reported and observed retained catches can not be

easily made. However, the amount of product being produced is

expanded up to round weight using the same method as for the

catcher/processors, so the same retained weight problem exists.

Additionally, for plants, motherships, and floating processors,

there is a large difference in the amount of discard being

reported by observed catcher vessels as compared to the amount

reported from unobserved catcher vessels. Tables 22 and 23 show

the total reported and total observed groundfish catch and the

associated amounts of discards. Except for 1990 in the Bering

Sea, the unobserved amounts of reported discard compared to the

unobserved amounts of reported retained catch is far less than

what would be expected based on the observed amounts of retention

and discard. This indicates that either negligible amounts of

discard are being reported by unobserved catcher vessels, or else

both observed and unobserved catcher vessels are reporting

substantially lower amounts of discards than are being observed.

Without the one-to-one comparison, it is not possible to tell

which is the case.
20

Based on the total catch comparison for observed

catcher/processors and the apparent under-reporting of discards

for plants/motherships, it appears that a serious underestimation of groundfish take (and it's associated catch of

prohibited species) is occurring.

One final concern relates to the large amount of observer

data that has no corresponding reported data from

catcher/processors, plants, floating processors, and motherships.

Tables 2 and 3 show the amounts of catcher/processor groundfish

catch that have a direct one-to-one relationship between observed

and reported data by processor-area-gear type-target. Tables 4

and 5 show the amounts of plant/mothership groundfish catch that

have a direct one-to-one relationship between observed and

reported data by processor-time period-area-gear type-target.

Tables 22 and 23 show the total reported and observed groundfish

catch. For the 2 years and two regions combined, 82.9% of the

observed catch and 75.5% of the reported catch matched for

catcher/processors, but only 50.8% of the observed catch and

66.0% of the reported catch matched for the plants and

motherships. Discussions with the NMFS staff in charge of

debriefing observers yielded the following explanation.

Personnel responsible for filling out the production logs at the

plants appear to pay little attention to area and gear type. If

the vessel reports catch from two areas and/or two gear types,

the likelihood exists that only one area and one gear type will

show up in the production logs. Additionally, the potential

exists for the catch to be attributed to areas other than the

area in which the fish are actually caught. If an area is in

danger of being closed, the fish have sometimes been attributed

to a different area.

CONCLUSIONS AND RECOMMENDATIONS

The system that is currently used by observers and the

fishing fleet to determine amounts of catch (total, retained, and

discarded) has too much room for error (intentional or

unintentional). The use of calculated average product recovery

rates and/or rates determined by public comment to convert

product weight to round weight often yields questionable results.

Large differences are seen in the reporting of discards between

observers and the shoreside/at-sea reports. Additionally,

observers and plant personnel use different methods to determine

the week, area, and gear type of the catch.

The result of this system is that it is possible that the

catch of groundfish in 1990 and 1991 has been under-estimated.

This affects not only the stability of the commercial groundfish
21

stocks, but also introduces the possibility that the estimates of

prohibited species catch are also too low.

The only way to resolve this problem is to weigh or directly

measure the total catch. For catcher/processors, this means

weighing or measuring the total catch at sea. For catcher

vessels, delivered catch is already being weighed (and plants now

have the option of including total retained weight in their

WPRs), but discard at sea must also be weighed or measured,

including the dumping of all or parts of the codends. The total

catch of each species should be our primary concern in terms of

conservation of the resource. Of secondary importance should be

the utilization question of how much and which species are being

retained and discarded. The current system reverses this order

of importance, and, as a result, makes it difficult to get an

accurate measure of total catch.

If the proposal for Individual Transferable Quotas (ITQs) or

some other type of individual vessel accountability is

implementated, the need for accurate estimates of total catch

will increase. Without better estimates, such management options

probably aren’t viable.


24

Table 1. --Gear type codes and target codes.

CODE GEAR TYPE

BTR Bottom trawl net

PTR Pelagic or mid-water trawl net

POT Strings of individual pots

LGL Baited longline gear

TARGETS

1990 Bering Sea/Aleutian Islands and Gulf of Alaska Targets (based on

retained catch) - targets are listed in order of determination

TARGET % OF TARGET

CODE CATCH SPECIES

Flatfish (excluding arrowtooth

Greenland turbot and Kamchatka

flounder,

flounder)

Pollock

Pollock + Pacific cod

also, Pacific cod < 5% of retained catch

Arrowtooth flounder + Greenland turbot

+ Kamchatka flounder

Sablefish

Rockfish

Pollock + Pacific cod

also, Pacific cod ≥ 5% of retained catch

Atka mackerel

O Any catch not targeted by the above procedure (miscellaneous)
25

Table 1 .--Continued.

1991 Bering Sea/Aleutian Islands Targets (based on total catch excluding

prohibited species and other non-allocated species) - targets are listed

in order of determination.

TARGET % OF TARGET

CODE CATCH SPECIES

Greenland turbot

Pacific cod

Rock sole + yellowfin sole + other flatfish

also, rock sole > yellowfin sole + flatfish

Rock sole + yellowfin sole + other flatfish

also, rock sole ≤ yellowfin sole + flatfish

Arrowtooth and Kamchatka flounder

Rockfish

Sablefish

Atka mackerel

Pollock

Pollock

0 Any catch not targeted by the above procedure (miscellaneous)
26

Table 1. --Continued.

1991 Gulf of Alaska Targets (based on total catch excluding prohibited

species, other non-allocated species, and arrowtooth flounder) - targets

are listed in order of determination.

TARGET % OF TARGET

CODE CATCH SPECIES

Pacific cod

Rockfish

Deep water flatfish

Shallow water flatfish + flathead sole

Sablefish

Pollock

Pollock

0 Any catch not targeted by the above procedure (miscellaneous)
27

Table 2 .--Catcher/processor catch comparisons by region

and gear, 1990.
28

Table 2. --Continued.

* Gear code definitions are given in Table 1.
29

Table 3 .--Catcher/processor catch comparisons by region

and gear, 1991.
30

Table 3 .--Continued.

* Gear code definitions are given in Table 1.
31

Table 4. --Shoreside and mothership delivery catch comparisons'

by region and gear, 1990.
32

Table 4 .--Continued.

1 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code definitions are given in Table 1.
33

Table 5 .--Shoreside and mothership delivery catch comparisons*

by region and gear, 1991.
34

Table 5 .--Continued.

1 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code definitions are given in Table 1.
35

Table 6 .--Comparison between catcher/processor reports and

observer reports by gear and target in the Bering Sea

and Aleutian Islands Region, 1990.
Table 6 .--Continued.

36

* Gear code and target code definitions are given in Table 1.
37

Table 7 .--Comparison between catcher/processor reports and

observer reports by gear and target in the Gulf of

Alaska Region, 1990.
38

Table 7 .--Continued.

* Gear code and target code definitions are given in Table 1.
39

Table 8 .--Comparison between catcher/processor reports and

observer reports by gear and target in the Bering Sea

and Aleutian Islands Region, 1991.
40

Table 8 .--Continued.

* Gear code and target code definitions are given in Table 1.
41

Table 9 .--Comparison between catcher/processor reports and

observer reports by gear and target in the Gulf of

Alaska Region, 1991.
42

Table 9 .--Continued.

* Gear code and target code definitions are given in Table 1.
Table 10.--Comparison between catcher/processor reports and observer reports by NPFMC area,

gear, and target in the Bering Sea and Aleutian Islands Region, 1990.
Table 10. --Continued.
Table 10. --Continued.
Table 10. --Continued.
Table 10. --Continued.
Table 10. --Continued.
Table 10. --Continued.
Table 10. --Continued.

I Gear code and target code definitions are given in Table 1.

2 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 11. --Comparison between catcher/processor reports and observer reports by NPFMC area,

gear, and target in the Gulf of Alaska Region, 1990.
Table 11. --Continued.
Table 11. --Continued.
Table 11. --Continued.

1 Gear code and target code definitions are given in Table 1.

2 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 12.--Comparison between catcher/processor reports and observer reports by NPFMC area, gear,

and target in the Bering Sea and Aleutian Islands Region, 1991.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.
Table 12. --Continued.

I Gear code and target code definitions are given in Table 1.

2 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 13. --Comparison between catcher/processor reports and observer reports by NPFMC area,

gear, and target in the Gulf of Alaska Region, 1991.
Table 13. --Continued.
Table 13. --Continued.
Table 13. --Continued.

1 Gear code and target code definitions are given in Table 1.

2 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
68

Table 14 .--Comparison between processor reports and observer

reports for shoreside/mothership delivery by gear and

target in the Bering Sea and Aleutian Islands Region,

19901.

1 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code and target code definitions are given in Table 1.
Table 15 .--Comparison between processor reports and observer

reports for shoreside/mothership delivery by gear and

target in the Gulf of Alaska Region, 1990'.

1 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code and target code definitions are given in Table 1.
70

Table 16. --Comparison between processor reports and observer

reports for shoreside/mothership delivery by gear and

target in the Bering Sea and Aleutian Islands Region,

19911.
71

Table 16 .--Continued.

1

 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code and target code definitions are given in Table 1.
72

Table 17. --Comparison between processor reports and observer

reports for shoreside/mothership delivery by gear and

target in the Gulf of Alaska Region, 19911.
73

Table 17 .--Continued.

1

 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%. This should not effect

retained or discard percentages, however.

2 Gear code and target code definitions are given in Table 1.
Table 18 .--Comparison between processor reports and observer reports for shoreside/mothership

delivery by NPFMC area, gear,

Region, 19901.

and target in the Bering Sea and Aleutian Islands
Table 18. --Continued.
Table 18. --Continued.

1 Processor reported catch should exceed observed catch, because observer coverage was

less than 100%.

2 Gear code and target code definitions are given in Table 1.

3 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 19. --Comparison between processor reports and observer reports for shoreside/mothership

delivery by NPFMC area, gear, and target in the Gulf of Alaska Region, 1990'.
Table 19. --Continued.
Table 19. --Continued.

1 Processor reported catch should exceed observed catch, because observer coverage was

less than 100%.

2 Gear code and target code definitions are given in Table 1.

3 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 20. --Comparison between processor reports and observer reports for shoreside/mothership

delivery by NPFMC area, gear,

Region, 1991'.

and target in the Bering Sea and Aleutian Islands
Table 20. --Continued.
Table 20. --Continued.
Table 20. --Continued.

1 Processor reported catch should exceed observed catch, because observer coverage was

less than 100%.

2 Gear code and target code definitions are given in Table 1.

3 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
Table 21.--Comparison between processor reports and observer reports for shoreside/mothership

delivery by NPFMC area, gear, and target in the Gulf of Alaska Region, 1991'.
Table 21. --Continued.
Table 21. --Continued.

1 Processor reported catch should exceed observed catch, because

observer coverage was less than 100%.

2

 Gear code and target code definitions are given in Table 1.

3 For longline vessels, catches of sablefish are being listed instead of catches of flatfish.
87

Table 22 .--Total reported catch and total observed catch

by region and processor type, 19901.

BERING SEA/ALEUTIAN ISLANDS

PROCESSOR

VESSEL/PLANT

REPORTED

CATCH (t)

GULF OF ALASKA

% CATCH (t)2

OBSERVED

1 These totals are higher than the amounts shown in Tables 2 and

4, because those tables show only direct comparisons (same

vessel or plant, etc.), and this table shows all the reported

and observed catches, whether there is a match or not.

2 At the start of 1990, some observers did not differentiate

between retained and discarded catch, but only reported the

total catch. These data are not included in this report.

Observers actually reported the following total catches in 1990:

Bering Sea catcher/processors - 1,543,549.0 tons

Bering Sea shoreside/motherships - 439,835.l tons

Gulf of Alaska catcher/processors - 81,648.l tons

Gulf of Alaska shoreside/motherships - 55,447.0 tons

3 Reported catch should exceed observed catch, because observer

coverage was less than 100%. This should not effect retained or

discard percentages, however.
88

Table 23 .--Total reported catch and total observed catch

by region and processor type, 1991.

BERING SEA/ALEUTIAN ISLANDS

VESSEL/PLANT

REPORTED

PROCESSOR CATCH %

GULF OF ALASKA

OBSERVED

CATCH (t)1 %

1 These totals are higher than the amounts shown in Tables 3 and 5,

because those tables show only direct comparisons (same vessel or

plant, etc.), and this table shows all the reported and observed

catches, whether there is a match or not.

2 Reported catch should exceed observed catch, because observer

coverage was less than 100%. This should not effect retained or

discard percentages, however.
89

CITATIONS

Berger, J., and S. Hare. 1988. Product recovery rates obtained

aboard foreign fishing vessels operating in the northeast

Pacific Ocean and eastern Bering Sea, 1983-85.

U.S. Dep. Commer., NOM Tech.Memo. NMFS F/NWC-129, 81p.

Low, L-L., J. Smoker, L. Watson, J. Berger, and W. Eklund.

1989. A review of product recovery rates for Alaska

groundfish. U.S. Dep. Commer., NOM Tech.Memo. NMFS

F/NWC-175, 22p.
RECENT TECHNICAL MEMORANDUMS

Copies of this and other NOAA Technical Memorandums are available from the

National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22167

(web site: www.ntis.gov). Paper and microfiche copies vary in price. 

AFSC-

 

12 HARRISON, R.C. 1993. Data report: 1991 bottom trawl survey of the Aleutian Islands area,144 p. NTIS

No. PB93-186237.

11 LIVINGSTON, P. A., A. WARD, G. M. LANG, and M-S. YANG. 1993. Groundfish food habits and

predation on commercially important prey species in the eastern Bering Sea from 1987 to 1989,

192 p. NTIS No. PB93-184703. 

10 KINOSHITA, R. K., and J. M. TERRY. 1993. Oregon, Washington, and Alaska exports of edible fishery

products, 1991, 47 p. NTIS No. PB93-159101.

9 KARINEN, J. F., M. M. BABCOCK, D. W. BROWN, W. D. MACLEOD, JR., L. S. RAMOS, and J.W.

SHORT. 1993. Hydrocarbons in intertidal sediments and mussels from Prince William Sound, Alaska,

1977-1980: Characterization and probable sources, 69 p. NTIS No. PB93-159093.

 8 WING, B. L. 1993. Winter oceanographic conditions in the eastern Gulf of Alaska, January-February

1986, 53 p. NTIS No. PB93-158335.

7 ARMISTEAD, C. E., and D. G. NICHOL. 1993. 1990 bottom trawl survey of the eastern Bering

Sea and continental shelf, 190 p. NTIS No. PB93-156677.

6 WOLOTIRA, R. J., JR., T. M. SAMPLE, S. F. NOEL, and C. R. ITEN. 1993. Geographic and bathymetric

distributions for many commercially important fishes and shellfishes off the West Coast of North America,

based on research survey and commercial catch data, 1912-84, 184 p. NTIS No. PB93-167682. 

5 GUTTORMSEN, M., R. NARITA, J. GHARRETT, G. TROMBLE, and J. BERGER. 1992. Summary

of observer sampling of domestic groundfish fisheries in the northeast Pacific Ocean and Eastern Bering

Sea, 1990, 281 p. NTIS No. PB93-159085.

4 GUTTORMSEN, M., R. NARITA, and J. BERGER. 1992. Summary of U. S. observer sampling

of joint venture fisheries in the northeast Pacific Ocean and Eastern Bering Sea, 1990, 78 p. NTIS No.

PB93-127546.

3 JOHNSON, P. A., S. D. RICE, and M. M. BABCOCK (compilers). 1992. Impacts of oil pollution

and Prince William Sound studies: Bibliography of 1960-91 publications and reports, Auke Bay Laboratory,

98 p. NTIS No. PB93-114064.

2 KAJIMURA, H., and E. SINCLAIR. 1992. Fur seal investigations, 1990, 192 p. NTIS No. PB93-

109080.

1 MERRICK, R. L., D. G. CALKINS, and D. C. MCALLISTER. 1992. Aerial and ship-based surveys

of Steller sea lions (Eumetopias jubatus) in southeast Alaska, the Gulf of Alaska, and Aleutian Islands

during June and July 1991, 41 p. NTIS No. PB92-235928.