U.S. Dept Commerce/NOAA/NMFS/NWFSC/Publications
NOAA-NMFS-NWFSC TM-31: Data Collection -- Groundfish (cont):
4.1 Introduction
California has a long history of commercial
fishing, dating back to at least the 1860s. Groundfish became
an important component of the commercial fishery soon after the
first dragnet was towed along the bottom of San Francisco Bay
by two lateen sail boats (paranzella trawl) in 1876. From that
time to the present, groundfish have provided an abundant and
consistent supply of fish to the California fishing industry.
Groundfish landings in California averaged around 10 million
lb annually from the mid-1920s through the 1940s. From 1980 to
1992, annual landings averaged nearly 90 million lb.
4.1.1 Geographical Overview
Major ports
From 1991 to 1992, 11 California ports
(Fig. 4.1) received annual landings of groundfish that exceeded
1 million lb (Fig. 4.2, A and B). The percentage of the total
groundfish catch for each of the major ports in 1992 was as follows:
Crescent City (22%), Eureka (21%), Fort Bragg (9%), Morro Bay
(9%), Bodega Bay (9%), San Francisco (8%), Princeton (5%), Moss
Landing (5%), Avila (4%), Santa Barbara (2%), and Monterey (2%)
(Fig. 4.2B). Twenty-six minor ports accounted for a total of
4% of the groundfish landings in 1992.
Major fishing grounds
Fishing for groundfish occurs almost continuously
along the California coast from the Oregon border to the Mexico
border; however, most groundfish are landed from Morro Bay northward.
Trawl-caught groundfish accounted for roughly 77% of the total
landings annually from 1991 to 1992 (Fig. 4.3, A and B). Line
gear produced the next largest component (about 14%) during this
time period, while set-net and trap landings were 5% and 1%, respectively.
In general, trawl gear is not used south
of Point Conception; instead, groundfish are predominantly caught
using line gear. North of Point Conception, trawl vessels fish
at depths of 20-500 fathoms. The use of set nets is prohibited
north of Point Reyes, and due to concerns for marine mammals and
birds, these vessels are restricted from fishing in many nearshore
areas south of Point Reyes. Traps and hook-and-line gear are
used from the Oregon border to the Mexico border to catch rockfish
and sablefish.
Principal species landed
In the Eureka INPFC (International North
Pacific Fisheries Commission) area, the three major groundfish
species landed in 1992 were Pacific hake (34%), Dover sole (22%),
and thornyhead (15%) (Table 4.1). In the Monterey INPFC area,
the three major species landed in 1992 were Dover sole (26%),
sablefish (11%), and chilipepper (11%). In the Conception INPFC
area, the three major species landed in 1992 were Dover sole (28%),
unspecified rockfish (22%), and thornyhead (16%).
Port biologist locations
The marine management functions of the
California Department of Fish and Game (CDFG) are accomplished
at the local level through Marine Resources Division management
units, with personnel stationed at various locations (Fig. 4.4).
Each unit encompasses one or two counties and is staffed by one
unit manager (associate biologist) and one or two assistant unit
managers (biologists). Marine management units are located in
Eureka, Fort Bragg, Bodega Bay, Menlo Park, Monterey, Morro Bay,
Santa Barbara, Long Beach, and San Diego. The Groundfish Coordination
Unit (GCU), located in Menlo Park, serves as a clearing house
and repository for groundfish data.
In 1992 the Pacific States Marine Fisheries
Commission (PSMFC) administered Pacific Fisheries Information
Network (PacFIN) funds to support seven full-time and one part-time
fisheries technicians to assist with port sampling duties, and
a data technician and an associate programmer analyst to assist
with data processing. Currently, the majority of California groundfish
sampling activity is performed by PSMFC fisheries technicians.
Supplemental sampling is performed by CDFG biologists and scientific
aides.
Fisheries technicians ("port samplers")
are assigned to major ports or port complexes (Table 4.2); however,
some ports are never sampled, including several in the San Francisco
Bay area. In 1992 there were no groundfish samples taken in southern
California. Almost all samples are collected at processing plants
adjacent to the docks where fish are unloaded.
4.1.2 History of Data Collection Systems
In California, systematic groundfish sampling
began during the early 1960s. The focus during those years was
primarily species of flatfish (Dover, English, and petrale sole),
which together represented the major component of the groundfish
landings. Additionally, a short-term study was conducted at several
ports from 1962 to 1963 to determine the species compositions
of the rockfish landings (Nitsos 1965).
Comprehensive sampling of rockfish landings
did not begin until 1977, when the Cooperative Rockfish Survey
was established. The survey is a fisheries monitoring program
operated jointly by the CDFG and the National Marine Fisheries
Service (NMFS). This cooperative sampling arrangement has remained
virtually unchanged since its inception nearly two decades ago.
However, major restructuring of the program occurred in 1992
in an effort to strengthen the collaborative role of the two agencies
and to improve sampling statistics and program documentation.
The CDFG Landing Receipt System, which
was the mandated system for recording commercial landings (see
section 4.2), was started in 1917 and by 1930, "punch cards"
and IBM tabulating machines were used to summarize the data.
The current system uses a DEC/Alpha server located in Sacramento,
with data entry performed by the Marine Fisheries Statistical
Unit (MFSU) in Long Beach.
The trawl logbook, which is the mandated
system for recording the catch locations, date, and amount of
commercial catches, is the oldest CDFG logbook system. Trawl
logbooks were introduced in 1933, as part of the official statistical
system of the CDFG. At that time, the trawl logbook and landing
receipt were combined on one form. This worked satisfactorily
because wholesale houses owned the boats and gear and operated
the fleet with paid crews. During the 1930s the dominant fishing
method was sail-powered pair-trawlers towing paranzella nets.
By 1944 the dominant fishing method was otter-board trawls towed
by a single diesel-powered vessel, not necessarily owned by the
company receiving the fish. This prompted the CDFG to design
a new logbook, independent of the Landing Receipt System, to meet
the needs of the developing fishery.
Through 1975 the logbook data were verified
and edited by biologists, collated with corresponding landing
receipts, and then forwarded monthly to the MFSU. The data were
keypunched and summary reports were generated annually by April
or May of the following year. With the need for greater resolution
of catch by area data, the use of a computer system became necessary.
A program developed in cooperation with NORFISH, a University
of Washington Sea Grant program, was used to process the 1976-77
logbook data. In 1976, the enactment of the Magnuson Fishery
Conservation and Management Act resulted in the formation of the
Pacific Fishery Management Council (PFMC), and the formulation
of the Pacific Coast Groundfish Fishery Management Plan (FMP).
A provision of the FMP was to develop a uniform, coastwide trawl
logbook. The PFMC provided a contract to the CDFG to develop
a computer system that addressed the new logbook format (Goodrich
1988). This system has been used to process logbook data from
1978 to the present.
Documentation
This chapter represents an overview of
the California groundfish sample collection and data processing
systems. Other documents provide important additional information
on subsets of the system and a historical perspective. The California
Department of Fish and Game Operations Manual, sections 4370 through
4372, contains information on the authority for development of
groundfish management, establishes and defines the position of
the groundfish coordinator (Menlo Park), and reviews data collection
procedures.
Documentation of sampling protocols are
given in the California Cooperative Commercial Groundfish Survey
Sampling Manual (GCU 1995) for the collection of rockfish and
other biological samples. Sen (1984, 1986) provided an overview
and statistical evaluation of the Cooperative Rockfish Survey
as it existed in the early 1980s. Nitsos (1965) provided information
on a sampling method that was used during the early 1960s.
The existing Landing Receipt System and
a proposed, but unimplemented revision are detailed by Ernst and
Young (1989) as part of their feasibility study report for improving
the Marine Fisheries Statistical System. This report contains
detailed information of the actual programs used in processing
the data. The methods used to collect and compile the fishery-related
data associated with the Marine Fisheries Statistical System for
the years from 1936 to 1952 are presented in Conner et al. (1952).
4.1.3 Legal Authority to Collect Data
Obligations of fishers
California Fish and Game Code statute sections
8010, 8016, 8043, 8046, and 8047 grant authority to CDFG personnel
to collect commercial fish landing information and requires fish
receivers to maintain copies of landing receipts for four years.
California Fish and Game Commission Division 1 (Title 14), and
California Code of Regulations sections 176 (trawl fishing activity
records), 174f (permit to use gill nets or trammel nets for commercial
purposes), 180f (traps), and 120 (prawn and shrimp trawling) grant
authority to CDFG staff to collect logbooks. Information collected
by the CDFG is generally governed by the California Fish and Game
Code section 8043 and the Information Practices Act as stated
in the California Civil Code section 1798 et seq.
Noncompliance
Failure to comply with the above listed
statutes results in the following penalties as listed in section
12002 (Punishment) of the California Fish and Game Code. "Unless
otherwise provided, the punishment for a violation of this code,
which is a misdemeanor, is a fine of not more than one thousand
dollars ($1,000), imprisonment in the county jail for not more
than six months, or both the fine and imprisonment."
4.2 Fish Ticket/Landing Receipt System
In California, official landing receipts
(fish tickets) must be completed for all fish or shellfish purchased
or received by commercial fish dealers (persons licensed as a
fish receiver or multi-function fish business). Landing receipts
are required for the following transactions: 1) upon receipt or
purchase of fish from a commercial fisher not licensed as a fish
receiver, and 2) upon receipt or purchase of fish from a commercial
fisher licensed as a fish receiver, when the commercial fisher
has not previously made out a landing receipt or if an original
receipt has been voided. The principal purpose for requiring
the landing information is to "gather and prepare data of
the commercial fisheries, showing particularly the extent of the
fisheries and the extent to which the various species abound"
(California Fish and Game Code statute section 8010).
There are currently 14 types of landing
receipts, of which 12 include categories for groundfish transactions.
Examples of landing receipts with groundfish categories are presented
in Figures A-3 and A-4.
The fish dealer determines which landing
receipt is used based on the fishing gear used and the market
categories that compose the landing. The fish dealer is legally
obligated to include the date, market category, landing weight,
price, port, gear, area fished, vessel registration number and
name, dealer number and name, and fisher license number and name
on each landing receipt.
Reports that include information regarding
catch by area fished from landing receipt data are usually based
on the port where the fish were landed. There is a field on the
landing receipt that specifies area caught (e.g., PSMFC area);
however, in the past the accuracy of this information has been
questioned. In recent years, editing at the MFSU has resulted
in more accurate recording of area fished information.
California levies a tax on the value of
fish landings, but the Landing Receipt System is not used directly
for assessing the tax. Instead, taxation is based on monthly
processor reports that are the responsibility of the Compliance
and External Audits Branch (CEAB), which ensures that commercial
fish businesses are remitting appropriate taxes to CDFG. Tax
reports and landing receipt data are compared only during audits.
4.2.1 Market Categories
The market categories listed on the landing
receipts (e.g., Figs. A-3 and A-4) represent individual species
or groups of species. Market categories are defined by different
sizes of fish, price, or mandated by federal/state regulations.
There are currently 94 groundfish market categories officially
recognized by CDFG, including 47 nominally single species rockfish
market categories and 10 multi-species rockfish market categories.
The CDFG Technical Services Branch (TSB)
in Sacramento is responsible for the assignment of three-digit
market category codes. If a unit biologist, a marine supervisor,
or the groundfish coordinator determines that a market category
needs to be added or deleted, they must send a formal written
request to TSB.
4.2.2 Processing System
Landing receipts are issued to the fish
dealers by CDFG. Dealers are legally obligated to mail completed
landing receipts to CDFG on or before the first and the 16th of
each month, depending on the date of the landing transaction.
The Department provides stamped and addressed envelopes for mailing
landing receipts. All landing receipts were modified in 1993
to accommodate Optical Character Reader (OCR) technology that
allows automated entry of landing receipt information. A flowchart
that describes the overall processing system for landing receipts
is presented in Figure 4.5.
Currently, all CDFG marine units edit landing
receipts and then forward them to the MFSU in Long Beach. About
75% of the landing receipts have errors, with missing vessel registration
numbers and invalid market category names being the most common.
Other errors include missing or incorrect block (catch area),
prices, gear codes, and dealer numbers. Because the unit biologists
are generally familiar with vessels and their landings, they are
able to identify and correct many of these errors.
At the MFSU, the landing receipts are processed
using the OCR scanning technology. Considerable editing occurs
at the OCR edit stations, including validation for missing fields,
reference checks against lists of dealers, fishers, and vessel
registration numbers and names. Additionally, a program checks
to ensure catch weights and prices are within a specified range
of values. Files created in the OCR process are stored and transmitted
nightly via telephone links to the Alpha server in Sacramento.
An extensive data validation process on the Alpha server is used
to detect missing or invalid fields, including those not checked
in the OCR process. A transaction report is created for updates
and corrections. Corrections are processed manually using personal
computer work stations.
A preliminary report of the catch by month
and port for a calendar year is issued about six months after
the end of the year. A final report (referred to as the Bulletin
Tables) is printed and bound as a public document for release
in October or November. The value of the catch is also included
in the final report. If there are less than three dealers who
buy fish in a given port, then the landings are reported within
a larger port group to ensure confidentiality. The 1992 Bulletin
Tables were the 52nd in a series that was first published in 1929
(CDFG 1992).
4.2.3 Groundfish Landings Not Covered
by the Landing Receipt System
Some landings of groundfish in California
are not accounted for in the current Landing Receipt System.
Groundfish caught by the recreational fishery are not included
in any CDFG data system at this time. Estimates of recreational
catches are given in Marine Recreational Fishery Statistics Surveys
prepared by the NMFS (e.g., USDOC 1992). The sampling procedures
and estimation methods used to generate landing statistics for
the marine recreational fishery in California are currently under
re-evaluation. Estimates of recreational groundfish landings
in 1989 were approximately 6,045 t, which was roughly 17% of the
commercial groundfish catch for that year.
Numbers of groundfish caught by Commercial
Passenger Fishing Vessels (CPFV) are recorded on logbooks and
entered into a separate CPFV system. The CPFV system is maintained
independently and is not cross-referenced with the commercial
fishery Landing Receipt System.
Transportation receipts are used by fishers
when the catch is landed and moved to another site before being
sold to a fish dealer. Transportation receipts are not currently
entered into the data system, but are maintained in a permanent
file system by the MFSU. Sometimes dealers fail to fill out a
landing receipt when a transportation receipt has been filled
out. These unrecorded landings are most likely minor relative
to the total commercial landings represented by landing receipts;
however, in some ports they can be significant. For example,
in the San Francisco area unreported hook-and-line landings could
be as high as 30% of the total reported commercial landings.
4.3 Logbook System
For the trawl fishery, CDFG uses the standardized
Washington-Oregon-California Trawl Logbook. Trawl and CPFV logbooks
are the only logbooks that are keypunched by the MFSU and included
in the marine fisheries system on the Alpha server in Sacramento.
4.3.1 Groundfish Trawl
Collection
Typically, trawl logs are collected by
the port samplers once a month or the vessel operators mail the
logs to the nearest CDFG marine management unit. Vessel operators
are required by law to file their logs for the preceding month
by the 10th of every month.
Data entry and error checking
A flowchart that describes the overall
processing system for logbooks is presented in Figure 4.5. Trawl
vessel operators are legally required to complete a log for each
trip. Logs are first edited by port samplers or unit biologists
to assign each tow to a single 10 square-mile geographic "block"
as defined by the CDFG block system that was established in 1933.
The charting of the coastal waters of the state into fishing
area blocks was completed concurrently with the designing of the
first trawl logbook (Clark 1935). Assignment to a block is based
on the Loran coordinates and depth at which a tow was made. Only
the block data are keypunched; Loran coordinates and latitude
and longitude are not currently captured.
After editing is complete, logbooks are
accumulated by the GCU in Menlo Park, then mailed to the MFSU
in Long Beach for data entry. Logbook data are keypunched twice
in Long Beach and compared for verification. As of June 1995,
annual processing of logbook data has been completed for 197892.
After all logbooks for one year have been
keypunched and compared, final error checking is conducted using
a program within the trawl logbook system. This program identifies
fatal errors, such as invalid or missing trip return dates, block
numbers, or vessel registration numbers, then generates an error
report that is subsequently sent to the GCU for review. A manual
search through the trawl logs is made to locate the source of
the errors and to correct them. These corrections are sent back
to the TSB, where they are keypunched into the existing database.
After the logbook database has received
its final corrections, the TSB in Sacramento submits the data
to an annual processing routine that matches logs with landing
receipts. The market categories that have been matched successfully
are then converted to one of 27 trawl market categories in the
logbook database.
The logs and trawl landing receipts are
matched by vessel registration number and trip return date. Because
landing receipts are sometimes completed after the date of the
landing, unmatched logs and unmatched tickets are reprocessed
by subtracting one day from the landing receipt date and rerunning
the matching process. After five processing cycles, all unmatched
logs are deleted from the system and unmatched landing receipts
are converted to "dummy" logs for compliance tracking
and effort estimations. In addition, fishing trip summary records
are created to be used primarily in a hail adjustment program.
For a given fishing trip, discrepancies between the logbook data and the associated landing receipt are addressed using a hail adjustment program that prorates the poundage from the receipt among the individual tows from the log. If the market category pounds listed on the landing receipt are greater than those on the corresponding trip summary record, the surplus pounds are distributed among trawl tows where that market category occurs. If market category pounds on the landing receipt are less than those on the trip summary record, the missing pounds are subtracted from trawl tows where that market category occurs. Market category landings found on a receipt but not in a logbook are distributed equally among trawl tows for that fishing trip. Species found in the logbooks but not present on the landing receipt are deleted.
The final logbook data file consists of
adjusted logbook records (record "type 1") and dummy
logbook records (record "type 2"). Reports are created
by month, INPFC area, and block number. The logbook data file
is downloaded to a Bernoulli cartridge and sent to the GCU for
distribution. The block data from the trawl logbook database
have never been merged with the landing receipt database to determine
specific areas where catches were made. At this time, California
does not analyze fishing effort based on the trawl logbook data.
Logbook coverage of the groundfish trawl
fishery by port and quarter in 1992 is presented in Table 4.3.
In general, the major ports, which are associated with relatively
large amounts of landed groundfish (e.g., Crescent City and Eureka),
were characterized by high logbook return rates, where at least
80% of the landing receipts had a corresponding log. The minor
ports (e.g., San Pedro and Long Beach) were characterized by considerably
lower logbook return rates than the major ports, where usually
less than 10% of the landing receipts had a corresponding log.
Approximately 70% of all trawl landing receipts processed in
California in 1992 also had corresponding trawl logs.
4.3.2 Other Gears
Other CDFG groundfish logbooks include
gill net, daily trap, daily sablefish trap, and Commercial Passenger
Fishing Vessels (CPFV). In most cases, only limited information
from these logbooks is entered into computers and can be retrieved
electronically. Sablefish logbooks are forwarded to and edited
by the GCU. The CPFV logbooks are mailed to Long Beach and are
entered as CPFV landings. Although the need for a hook-and-line
logbook has been recognized in recent years, current financial
constraints have prevented its implementation.
Two other logbooks contain groundfish information.
There is a shrimp logbook that includes a field for the amount
of groundfish caught by the vessel; however, no formal analyses
have been conducted to determine the extent to which this field
is used. Regardless, data from these logbooks are not entered
into the mainframe computer system, and thus, cannot be merged
with either the trawl logbook information or the landing receipts.
There is also a salmon logbook that includes a field for the
vessel's rockfish bycatch; completion of this logbook is currently
voluntary.
Future plans for processing commercial
fishery data include an automated method for tracking logbook
information and the use of OCR equipment for scanning logbooks.
Data captured from each type of logbook may vary to some extent;
however, common data can be standardized and criteria for matching
these data with the landing receipts can be more clearly defined
than the current evaluation methods. Plans to modify the processing
system for logbooks have been developed to provide CDFG biologists
with more detailed information than is currently available to
assess the impact of commercial fishing on various fisheries.
4.4 Species-Composition Sampling
California's commercial groundfish sampling
program, which includes species-composition sampling as well as
biological sampling, is coordinated at the state level by the
groundfish coordinator in Menlo Park and at the local level by
marine unit biologists. Port samplers, stationed at various ports
(Fig. 4.4), sample only rockfish market categories to determine
the species compositions of the landed catch. Historically, most
rockfish landings were caught using trawl gear in northern California
(Morro Bay and north). Thus, the sampling program was largely
designed to cover that gear and area. Only limited sampling has
been conducted for the line (hook-and-line and longline) and set-net
(set gill and trammel nets) fisheries throughout the state.
When the current sampling program began
in 1977, the goal was to obtain samples from every market category
contained within a sampled boat trip (Tomlinson 1977). However,
this sample selection procedure proved to be impractical, given
the logistical and time constraints associated with collecting
information at the fish processing locales (sample sites). Sen
(1984, 1986) demonstrated that species and age compositions could
be estimated by treating the market categories separately and
then summing the estimates over the market categories. The current
sampling program does not require all of the market categories
within a given boat trip to be sampled, and thus, there are generally
no estimates produced that address the statistical properties
of the individual boat trips.
The species-composition sampling program
used in Oregon is also largely based on the design proposed by
Sen (1984, 1986) and the following discussion is generally similar
to the analogous section presented in the Oregon chapter (section
3.4). However, differences do exist between the two sampling
approaches, dictated primarily by the unique fishery operations
in each state; therefore, the sections are presented independently
of one another.
California's species-composition sampling
is based on a stratified, two-stage random sampling design. Port
complex and quarter combinations are treated as strata, and boat
trips within a stratum represent the first-stage sampling units.
The boat trip landings are poststratified into market categories.
Typically, two "clusters" (baskets of fish) of a fixed
weight are subsampled within each market category at the second
stage of sampling.
The current species-composition sampling
program for rockfish is designed around the market category as
the "domain of study" (Cochran 1977). Thus, the primary
goal of the sampling design is to obtain reasonable estimates
of the species compositions of the important market categories
for a given port complex and quarter stratum. A port complex
is a grouping of ports sampled by a CDFG unit, where each CDFG
marine unit is responsible for sampling the major port for the
area and other nearby minor ports.
There are 57 rockfish market categories
that are currently defined, and each of these categories could
potentially be landed by each gear type (trawl, line, set net,
etc.). There are 47 nominal rockfish species market categories
and 10 combined species market categories. Not all of the possible
combinations of market category and gear type are routinely sampled;
a number have never been sampled, and some have never been used.
Landings in 1992 for southern and northern
California by gear type and market category show that relatively
few market categories contributed to the total landings for each
of the major types of gear (Table 4.4). For example, for northern
California ports, approximately 73% (in weight) of the rockfish
caught with trawl gears was landed within the thornyhead and unspecified
rockfish market categories. Another roughly 18% of the rockfish
catch taken by trawl gears and landed at northern California ports
was associated with three other categories, namely the widow rockfish,
chilipepper, and bocaccio market categories. The line fishery
was also sampled fairly intensively in 1992. The line fishery
of northern California used the most (28) market categories for
landing rockfish catches. In 1992, no sampling for purposes of
species-composition evaluations was conducted at southern California
ports or for fisheries in northern California that employed gears
other than trawls, set nets, or lines.
In annual analyses and reports, the minor
market categories (i.e., categories that receive relatively few
rockfish landings and usually no sampling) are typically combined
with major market categories that have been sampled. Through
1992, the target sampling rates were set at four samples per major
market category per month, but this goal was rarely met. Sampling
effort is currently determined by a priority scheme that distributes
the total time allocated to sampling among the major rockfish
market categories for the trawl, set-net, and line fisheries (see
section 4.4.2 for an example of a priority list). This sample
allocation scheme is applied to each of the port complexes. The
Pacific hake, Dover sole, lingcod, and sablefish fisheries are
also subjected to a sampling schedule that is based on a priority
list.
Among the rockfish, no market category
is assumed to be completely "pure" (composed entirely
of a single species). However, several market categories are
assumed to consist largely of a single or small number of species,
and for this reason they are analyzed somewhat differently than
the other, "less pure" categories. For example, the
widow rockfish market category is generally thought to be nearly
pure. The thornyhead market category is thought to consist almost
solely of the two species of thornyhead, longspine and shortspine
thornyhead. The longspine and shortspine thornyhead market categories
were added to the CDFG market category list in 1994. In January
1995, these two market categories were required to be landed as
pure categories. In January 1991, bocaccio were required to be
landed as a pure market category. When samples are available
for individual market categories, including the pure categories,
final landing estimates are based on the estimates of species
composition determined from the samples and not on an assumption
that the landings are pure.
4.4.1 Sampling Protocol
To estimate the species compositions of
the landings, a number of boat trip samples are selected for each
market category (domain of study). Port samplers choose particular
trips to sample based on their own judgement, including the vessel's
arrival time, information received from a dealer, or scheduling
conflicts. Difficulties associated with obtaining strictly "random"
samples from commercial fisheries are addressed in section 3.4.1.
Except in special circumstances described
below, samples consist of clusters taken from a given market category
contained within a boat trip. Clusters are subsamples (baskets
of fish) that are a fixed weight, rather than a fixed number of
fish. Generally two clusters are taken per sample, although occasionally
samples consist of one or, more rarely, three clusters. Clusters
are usually 50 ± 5 lb in size, but 25 ± 2 lb clusters
are selected for some market categories that contain small fish,
such as the thornyhead market category. In most cases, all of
the clusters selected from a given market category have the same
target size. However, samples from the nearshore hook-and-line
fishery often consist of relatively small clusters (less than
25 lb in size), because total landing weights are frequently less
than twice the target cluster size.
Clusters can be taken from the fillet tables,
bins, or directly from boxes as they are unloaded from the vessel.
The actual sampling site depends largely on where the fish are
located in the landing or processing stage when the sample is
taken. In general, two clusters are taken from different portions
of the market category catch, in order to obtain a more representative
description of the species composition. For example, if some
of the landings were in a bin, and another portion was on a fillet
table, one cluster would be selected from each area. If the entire
catch was unloaded into a single bin, generally one cluster would
be taken from the center of the bin and another selected from
a corner. If more than one bin were available, then the two clusters
generally would be taken from different bins.
In some cases, certain fish are selected
from a landed market category and placed into groups differing
in composition ("subsorts") before a sample can be obtained.
Generally subsorts are based on a single species or a certain
size range of a single species. In these cases, the sampler is
expected to collect a sample from each subsort of the market category.
When a market category consists of subsorts, time constraints
often preclude a sampler from obtaining more than a single cluster
per subsort.
All fish in each cluster are counted and
identified to the species level. A combined weight is obtained
for each species (all individuals pooled) within a cluster. When
possible, the sex and length are recorded for every fish in each
cluster.
A port sampling manual is available that
describes in detail the selection procedures used by samplers
to obtain species-composition samples from rockfish landings in
California (GCU 1995). Newly employed samplers receive on-the-job
training from experienced port samplers and unit biologists.
Currently, all port samplers record information on standardized
data sheets; however, historically, this was not the case. In
prior years, the sampling data sheets were not uniform coastwide
and some samplers used otolith storage (coin) envelopes to record
information, while others used data sheets that were unique to
their individual ports. Sampling is
usually conducted during daylight hours on weekdays (Monday through
Friday); however, sampling occasionally
takes place at night and on weekend days.
4.4.2 A Hypothetical Example
In 1993, a new sample allocation plan was
implemented that redefined the sampling tasks of the port samplers.
The plan encompassed the species-composition sampling program
for rockfish, as well as the sablefish, Dover sole, and lingcod
sampling programs. Prior to 1993, these four programs had sampling
goals that were independently established, and, in effect, competed
with one another for a sampler's time. This proved to be a generally
unsuccessful sampling approach because one or more of the programs
usually received inadequate sampling attention. The goals of
the new plan were to: 1) effectively apportion sampling effort
among the sablefish, Dover sole, and lingcod programs, and among
market categories for rockfish, and 2) ensure that the sampling
effort within each of the programs was distributed over an extended
period of time so that sample information would be available throughout
the fishing season.
The new plan established sampling itineraries
based on a "priority list." That is, a port sampler
is required to first collect samples at the top of the list (high
priority), completing each sampling task before proceeding to
other tasks at the bottom of the list (low priority). At the
beginning of a new quarter, the port sampler starts from the beginning
of the priority list again. Currently, the priority lists reflect
the specific characteristics of the individual port complexes.
The priority lists are constructed once a year at the Annual
Cooperative Survey Meeting. The sampling goals are determined
by analyzing the landings and sampling effort of the previous
year, and evaluating how well the sampler met the goals outlined
in the priority list of the previous year. The priority lists
also reflect any current directives established by the Groundfish
Management Team (GMT) to meet the needs of future stock assessments,
NMFS statisticians and biologists, the groundfish coordinator,
and other GCU staff. The GCU has the final decision and responsibility
for informing the port samplers of the new priority list.
The variability in fishery operations between
ports plays a significant role in what samples are taken and how
the priority list is used. The following priority list illustrates
the approach used in California to select commercial fishery samples.
This list, in descending order of importance, is applicable to
a port complex and quarter (samples denote individual boat trips).
Age structures (fin rays from lingcod and otoliths from other
species) are generally collected from selected species for up
to three cycles through the list during a quarter.
2. Trawl: widow rockfish market category - 1 sample.
3. Trawl: bocaccio market category - 1 sample.
4. Trawl: red rockfish (group) market category - 1 sample.
5. Trawl: sablefish market category - 1 sample.
6. Trawl: Dover sole market category - 1 sample.
7. Trawl: lingcod market category - 1 sample.
8. Trawl: chilipepper market category - 1 sample.
9. Trawl: thornyhead market category - 1 sample.
10. Line: unspecified rockfish market category - 2 samples.
11. Set net: unspecified rockfish market category - 2 samples.
12. Line: gopher rockfish (group) market category - 1 sample.
13. Set net: small rockfish (group) market
category - 1 sample.
The following example demonstrates how
a port sampler might use the priority list to decide which market
categories to sample.
A trawl boat arrives at a dealer and unloads
the following market categories: unspecified rockfish, bocaccio,
lingcod, and chilipepper. Following the priority list presented
above, the sampler first obtains a sample from the unspecified
rockfish market category. The sampler selects a 50 ± 5 lb
cluster from one of the bins that the unspecified rockfish catch
has been unloaded into using protocols discussed in section 4.4.1.
The sampler then sorts the cluster into individual species and
records their aggregate weights. Length, sex, and stage of maturity
are recorded for each fish in the subsample (cluster). Otoliths
are removed from those species that are included in a biological
sampling program for rockfish (see section 4.5). A second cluster
is collected from a different bin of unspecified rockfish, if
possible, and processed in the same manner as the first cluster.
Sample information collected in the field is written on standardized
data sheets, or in the case where length frequency boards are
used, the data are transcribed to the data sheets from the boards
after the sampler has returned to the office.
If time permits, the sampler will next
sample the bocaccio market category (number 3 on the priority
list). That is, two similar-sized clusters are selected from
the bocaccio market category using the same sampling protocols
that are discussed above for the unspecified rockfish market category.
Because bocaccio is currently included in the biological sampling
program, the otoliths from each sampled specimen are collected
in addition to the length, sex, and maturity information that
is routinely recorded.
Given that the sampler still has adequate
time to collect samples, a third market category from this boat
trip would be sampled. Lingcod (number 7 on the priority list)
are currently included in a federally coordinated sampling program
that involves the cooperation of all three Pacific coast states
(Washington, Oregon, and California). The federal sampling program
for lingcod is discussed further in section 5.2. The sampling
program for lingcod is generally similar to the stratified, two-stage
designs used in California and Oregon to obtain information regarding
the species compositions of rockfish landings. Given that at
least 200 lb of lingcod were landed, the sampler selects four
50 ± 5 lb clusters. The sampler is instructed to obtain
the four total clusters from as many different bins as possible.
The length and sex of each fish in the sampled clusters are recorded
and dorsal fin rays from the specimens are collected.
Again, if time permits, the chilipepper
market category (number 8 on the priority list) will be sampled;
however, fish operations currently used by dealers in some areas
do not typically provide a port sampler enough time to sample
more than three market categories per boat trip. The chilipepper
market category is sampled in the same manner as the unspecified
rockfish and bocaccio market categories.
4.4.3 Processing System
Because age-composition data (see section
4.5) and species-composition data are routinely processed together,
the discussion presented in this section describes the processing
system for both types of information. Species-composition data,
including fish length information, are entered directly into personal
computers by port samplers at marine units. Prior to 1992, data
entry was done using a FORTRAN program that directly stored data
in a binary form. From 1992 to 1993, the data entry component
of this program was replaced by customized database software that
was more "user friendly" than the original program.
Beginning in 1994, the entire FORTRAN program was rewritten in
QuickBASIC. The format used in the final end-of-year data file
has remained constant since 1977 to maintain a consistent file
structure for the species-composition data that are collected
annually. Every month port samplers send the data files for the
current quarter to the GCU. Data sheets are collected by the
GCU for permanent storage.
When age data become available, they are
appended to these data files. Personnel at the NMFS (Southwest
Fisheries Science Center, Tiburon Laboratory) enter all data associated
with ageing studies conducted at their laboratory. Age data generated
from other studies are entered by personnel from the GCU. Data
entry of all length and age information for Dover sole is done
by the Dover sole age reader located in Menlo Park.
The analysis procedures for summarizing
species- and age-composition information and for generating landing
statistics require a master data set. Because age data are entered
at two locations, there are often two different data files, one
containing ages entered by the NMFS staff and another that was
prepared by the GCU personnel. Annually, a routine in the data
entry program is used to merge the two data files of age information
together. The merged file is referred to as the "master"
data set of age information and is stored at Menlo Park and the
Tiburon Laboratory. The current processing system for species
and age-composition data reflects a design that provides information
in a format(s) that can be utilized by a diverse group of fishery
researchers and managers.
Error checking of data occurs at many levels.
Port samplers are responsible for checking their data entries
for accuracy. The current version of the data entry program checks
for a number of common errors during the entry process, such as
species codes that are not within a valid range, invalid species
lengths, invalid market categories, and characters that are entered
in fields where numbers are required. Any errors that are identified
by the program must be corrected before data entry can continue.
In addition, the sample data are extensively checked for missing
values and other errors by the GCU. For the species-composition
sample data that are sent to PacFIN, there is a BASIC program
on the Alpha server that checks for errors, such as blank fields,
duplicate records, and invalid species codes.
4.5 Biological Sampling
In general, the biological information
collected from California groundfish landings consists of sex,
size (length), age, and maturity data. The sampling design used
to collect biological data from landings of rockfish and Dover
sole is an extension of that used to collect rockfish species-composition
samples (see section 4.4). Biological sampling for sablefish,
lingcod, and Pacific hake is coordinated through a federal program
and is described in chapter 5.
It is important to note that biological
sampling requires considerably more time to administer in the
field than species-composition sampling, and can result in samples
with incomplete information. For example, time- and dealer-imposed
constraints often preclude samplers from performing the following
tasks for each biological sample: 1) determining the sex and stage
of maturity of each fish in the sample, 2) measuring the length
of each fish in the sample, and 3) collecting the age structures
from each fish in the sample.
4.5.1 Sampling Protocol
Rockfish
Rockfish species-composition sampling includes
collecting sex and size (length) information for all species when
possible. Maturity and age data are currently collected for bank
rockfish, bocaccio, chilipepper, darkblotched rockfish, widow
rockfish, and yellowtail rockfish. Only species composition and
size data can be collected when fish are to be sold whole and
a dealer will not allow them to be mutilated for purposes of extracting
otoliths and determining sex and stage of maturity.
Currently, biological sampling rates for
rockfish are determined for each market category (i.e., for those
species presented above) within individual port complex and quarter
combinations. Examples of biological sampling rates are included
in the priority list presented in section 4.4.2. The number of
age structures that have been collected from targeted species
of rockfish in California since 1955 are presented in Table 4.5.
Prior to 1993, otoliths were collected whenever a sampler had
adequate time to remove the structures while conducting a species-composition
sample. However, beginning in 1993, the number of samples in
which otoliths were removed from the sampled fish was reduced
so that the number of species-composition samples could be increased.
Port samplers clean the otoliths and store
them in coin envelopes. Once a month, the otoliths are shipped
to the GCU in Menlo Park. A technician sorts the otoliths and
sends the yellowtail and widow rockfish samples to the NMFS (Tiburon
Laboratory) for age analysis. Otoliths from chilipepper and bocaccio
are analyzed by the GCU. After age data have been recorded for
the otoliths, the structures are permanently stored at the facility
where they were analyzed. No age analysis has been conducted
for otolith specimens from bank and darkblotched rockfish, and
these age structures are stored at the Tiburon Laboratory. Over
the years, the commercial and recreational fishery sampling programs
conducted in California have generated a large number of otoliths
of various species, many of which have not yet been examined;
these otoliths are stored at Menlo Park and at the Tiburon Laboratory.
Prior to 1984, surface ages were recorded
from whole otoliths of widow rockfish; however, this method proved
to be unreliable for older fish and it was replaced by a break
and burn technique that is currently used to prepare otoliths
from widow rockfish for ageing. Analysis procedures involve the
enumeration of annual marks. Starting in 1992, only partial samples
(one cluster per sample) of widow rockfish were processed for
purposes of age determination. All otolith samples from widow
rockfish have been analyzed through 1994 (Table 4.5).
Otoliths from yellowtail rockfish are also
prepared and examined using the break and burn technique. Prior
to 1983, surface ages were recorded from whole otoliths of yellowtail
rockfish. Ages have been determined for all otolith specimens
from yellowtail rockfish through 1994 (Table 4.5).
There is a backlog of otolith specimens
from bocaccio and chilipepper to be analyzed due to staffing limitations
in recent years. However, an age reader was hired in 1993 to
work specifically on these reserves of unexamined otoliths. Ages
have been determined for all chilipepper otolith samples through
1990; samples taken since 1985 have been aged using every other
fish in a sample. Otoliths from chilipepper sampled after 1982
have been prepared and analyzed using the break and burn method.
Prior to 1982, only surface ages were recorded from whole otoliths
of chilipepper. Ages have not been determined for bocaccio otolith
specimens collected after 1985. All otoliths from bocaccio have
been examined whole; however, the validity of the results from
some of these analyses has been questioned by fishery researchers,
in particular the analysis conducted in 1985 (Bence and Hightower
1990).
Dover sole
Beginning in 1990, the only species of
flatfish to be routinely sampled for purposes of age determination
was Dover sole. However, since 1955, relatively small numbers
of English, petrale, and rex sole have been sampled as part of
the biological sampling program in California (Table 4.5). The
Dover sole market category is assumed to be pure (composed only
of Dover sole) and thus, it is not sampled for purposes of species-composition
determination.
Historically, landings of Dover sole were
primarily sampled at the ports of Morro Bay, Fort Bragg, and Eureka.
These samples of Dover sole provided sufficient biological data
for each INPFC area. From 1960 to 1990, biological samples collected
from landings of flatfish consisted of 50 randomly selected fish
per boat trip sample. Length and sex data were recorded for all
50 fish that were sampled; however, otoliths were removed from
only the first 25 fish.
In 1991, CDFG adopted the two-stage sampling
design that is based on selecting clusters (subsamples) of a fixed
weight, rather than a fixed number of fish. Current samples of
Dover sole consist of two 25 ± 2 lb clusters, where length
and sex data are recorded and otoliths are collected for all of
the fish in each cluster.
Otoliths from Dover sole are analyzed by
different age readers based on the INPFC area (i.e., port) where
the samples were collected. The break and burn technique is currently
used to prepare and analyze otolith specimens from Dover sole.
In the past, surface ages were determined from whole otoliths
of Dover sole; however, most of these samples have been re-analyzed
using the break and burn method. All otolith samples from Dover
sole collected within the Eureka INPFC area have been analyzed
through 1990 and also for 1994. In the Monterey INPFC area for
the years 1984-89 and 1994, the only otolith samples from Dover
sole that have been examined are those that were collected at
ports within the Fort Bragg complex. Ages have been determined
for only those Dover sole collected in 1985 for the Conception
INPFC area. Starting in 1993, otolith samples collected from
both the Monterey and Conception INPFC areas were assigned to
a single age reader in Menlo Park.
4.5.2 Processing System
Procedures used to enter and process biological
sample data are presented in section 4.4.3.
4.6 Estimating Derived Quantities
The procedures described below are currently
under review and could be changed in upcoming years, and not all
of these potential changes in the analytical methods will necessarily
be made retroactively. Users of landing estimates should check
with their data source for details of the procedures used to generate
the specific estimates they have requested.
4.6.1 Landings by Area
Landing estimates are calculated for each
port complex and not on an area-fished basis, such as PSMFC areas.
Consequently, it is not necessary to use logbook data to apportion
landings to fishing areas. It appears reasonable to determine
estimates by port complex in California because the vessels are
relatively small and tend to range only a short distance from
their home ports. In any case, until recently, there was a considerable
backlog of keypunching of logbook data, so it was not feasible
to use the data to derive current landing estimates.
4.6.2 Annual Estimates
Rockfish
Annual estimates of trawl-gear landings,
and age and length compositions, have been routinely generated
on a species-by-species basis for northern California (Morro Bay
and north). Similar estimates are now generated for set-net and
line gear landings, including southern California, in cases when
sampling was adequate.
The calculation of the estimates requires
the sample-composition data and landing receipt information for
each market category landed within each port complex and quarter
stratum. In practice, there are often market categories and port
complex and quarter strata for which no samples were taken. Thus,
the first step in the processing of the data is to reassign landings
to other quarters or port complexes, and/or to combine market
categories. Ultimately, these procedures generate a reduced set
of port complex and quarter strata and possibly market categories,
with the necessary data for each.
The method used to combine and reassign
the landings depends on the type of market category. Market categories
considered to be relatively pure (e.g., widow rockfish, bocaccio,
and thornyhead) are generally not combined with other market categories.
When possible, the landings for a quarter that were not sampled
are assigned to an adjacent quarter that had applicable samples.
If no samples were obtained from a port complex during a year,
then the landings for the market category are assigned to the
nearest port complex for which samples were taken, with the caveat
that landings are not reassigned across INPFC area boundaries
except when absolutely necessary. When there are two candidate
quarters or port complexes for reassignment, the landings are
reassigned to the candidate with the most samples.
Some efforts are also made to not combine
minor single species market categories with other market categories,
under the assumption that these categories would not be recorded
unless they were somewhat distinct. For example, if there were
samples for these market categories (minor single species market
categories, such as vermilion rockfish) in a given port complex
but not for every quarter of the year, then the landings from
the unsampled quarters would be reassigned to quarters that had
been sampled, instead of categories with other rockfish market
categories that had been sampled. If reassigning the landings
for these market categories to nearby quarters is not possible,
then the sample information is sometimes combined with the unspecified
rockfish market category for that port complex.
The method currently used to reassign the
landings of the mixed species categories of rockfish is also unique.
If samples were taken for a given mixed species market category
within a port complex and quarter stratum, then the landings for
that category and stratum are treated separately; otherwise, the
landings are combined with the unspecified rockfish market category
for that stratum. In the case that the unspecified rockfish category
is not sampled within a given stratum, then these combined landings
are reassigned to a quarter that was sampled, and if no quarter
was sampled, to the nearest port complex that was sampled. In
some prior years, mixed species market categories were combined
based on the judgements of the individual port biologists regarding
the similarity of the categories at their port.
Annual reports are generated using a list
of the sample data files, specific sort groups (market categories
that are combined and evaluated as though they were a single category),
and the landings that apply to the specified sort groups within
each port complex and quarter stratum. For each port complex
and quarter analyzed, landing estimates (in number) are determined
for individual species by length class and sex, and by age class
when age data are available. Total landings (in number and weight)
are also estimated for the individual species for each port complex
and quarter stratum. In these analyses, lengths are rounded to
the nearest centimeter, and unknown information (i.e., missing
values) for sex, length, and age is a recognized classification,
with estimates being calculated for the number of fish landed
in each of these classes. No attempt is made to reassign the
unknown sex, length, or age information to other classes, although
users of the data frequently need to do this.
The software first calculates estimates
for each of the specified sort groups, and then adds these values
together and reports the total quantity for all of the sort groups
combined; however, the totals are based on only those market categories
that were included in a sort group. Reports for individual sort
groups are not generated.
For a given port complex i and quarter
j, let the estimated quantity be designated as Vij.
Calculations of Vij are done separately for specified
sort groups and gear combinations, but these subscripts have been
dropped for simplicity. The Vij could be estimates of
the total number of fish landed of a particular species, the weight
landed for that species, the number of 8-year-old females of that
species, or any other sex/length or sex/age combination. The
quantity Vij is found by first calculating an average quantity
per pound of landings and then multiplying this value by the total
pounds landed.
The average quantity per pound, vij,
is calculated as a ratio estimate. Let the quantity observed
for a single cluster l on trip k be vijkl
(say the number of yellowtail rockfish observed in an individual
cluster). The average quantity per pound on trip k can
be estimated as,
where wijkl is the weight of cluster
l selected on trip k in port complex i and
quarter j.
The average quantity per pound on trip
k (vijk ) multiplied by the total pounds of the
sort group on trip k (Lijk) provides an estimate
of the total quantity for the trip. Values for Lijk are
determined from landing receipt information. The ratio estimator
of the average quantity per pound over all trips is then,
which is simply the ratio of the sum of the sampled quantities
to the sum of the landing weights of the sort group for all of
the trips sampled within the port complex and quarter stratum.
The estimate of the total quantity of the species for the specified
sort group within port complex i
and quarter j can now be calculated as the average quantity
per pound over all trips (vij) multiplied by the total reported
landing weight of the specified sort group within the port complex
and quarter stratum (Wij),
Values for Wij
are determined from landing receipt information. Note that the
values for Wij are almost always greater than the sum of
Lijk, because Wij is the sum of the landing weights
of the specified sort group for both sampled and unsampled trips.
No standard reports on variances are generated.
Estimates of variances have been occasionally generated following
procedures outlined by Sen (1986).
The information on age, size, and sex compositions
of the catch comes from the same samples used to estimate species
composition. Thus, numbers-at-age or size, by sex, are calculated
using essentially the same algorithms that are used to estimate
total number or weight landed.
Dover sole
Species-composition analysis is not done
on Dover sole because these landings are assumed to be pure.
Annual estimates of age and length compositions for Dover sole
are determined separately from the estimates for the rockfish
species, but the two sets of analyses use basically the same programs.
However, the problems associated with rockfish analyses that
are due to lack of sample data do not occur for Dover sole analyses,
because estimates for Dover sole are generated by INPFC areas
and not by port complexes. That is, landings of Dover sole are
never reassigned across INPFC area boundaries and sufficient levels
of sampling are obtained from each INPFC area. Estimates are
generated on a request-only basis and for the trawl gear only.
Annual reports are generated using a list
of the sample data files, the Dover sole sort group, and the landings
that apply to the Dover sole sort group within each INPFC area
and quarter combination. For each INPFC area and quarter analyzed,
landing estimates (in number) are determined for Dover sole by
length class and sex, and by age class when age data are available.
In these analyses, lengths are rounded to the nearest centimeter.
Since sex and age information is determined for all samples of
Dover sole prior to processing the annual reports, estimates for
missing values are not needed.
4.6.3 Monthly Estimates to PacFIN
In a separate process from the annual estimates,
estimated landings (in weight) for individual species are generated
monthly. First, monthly estimates of the species composition
of the landings are generated by the GCU based on the sample data.
These estimates are forwarded to Sacramento, where they are processed
together with data on landings for each market category.
The species-composition reports generated
in Menlo Park consist of separate records for each market category,
port complex, gear type, and month. Species compositions are
reported separately for: bottom trawl (beam trawl, otter trawl,
balloon trawl, roller gear trawl, and Danish seine); midwater
trawl gear; longline gear; and hook-and-line gear (vertical hook-and-line,
troll, and rod-and-reel). All gill- and set-net landings are
combined and reported to PacFIN as a single category. Other gear
types are generally unsampled and are not expected to contribute
significantly to the total landings of rockfish.
Species compositions are generated for
a gear group, not individual gear; therefore, the species compositions
for midwater and bottom trawls are identical, and similarly, longline
and hook-and-line species compositions are identical. Monthly
estimates are based on sample data collected over a series of
months. For months other than January and December, three months
of data are used. For example, the species composition for July
would be based on samples from June, July, and August. January
estimates are based on January and February data, and December
estimates on November and December data. Multiple months of data
are used because sampling intensity is generally too low within
a given month to provide reliable estimates of the landings.
Species compositions are calculated separately
for each port complex. Port complexes are not combined as is
done in the calculation of the annual estimates. Species compositions
are also calculated separately for each market category, which
are not combined together into sort groups as is done in the calculation
of the annual estimates. However, in past years the chilipepper/bocaccio
market category was combined with the unspecified rockfish market
category, but because bocaccio are now generally reported in their
own category, this combination of market categories is no longer
applicable. Species-composition reports are not prepared for
all landing categories (see below), because not all market categories
are sampled for each gear type.
Species compositions are reported as the
percent of the landings (in weight) that each species constituted.
These percentages are based on the estimators described above
for deriving the annual estimates. First, for a given market
category sampled on trip k within port complex i
and time period j (a 2- or 3-month time block), the average
weight per pound of a species is calculated using equation 4.1.
The weight of the species per pound of the market category over
all trips is then calculated in the same manner as the annual
estimate using equation 4.2.
The estimated percent of the landings (in
weight) that a species constitutes for the specified market category
within the port complex and time period combination is simply,
In the reports, the percentages are rounded to the nearest integer,
and species with percentages less than 0.5 (i.e., those that would
be rounded to zero) are not reported. The percentages for these
unreported species are summed together, rounded to the nearest
integer, and are reported as "unknown" fish if the rounded
sum is 1% or greater.
The estimated species compositions are applied to the reported
landings (for a corresponding year, month, port complex, gear,
and rockfish market category) by the PacFIN Coordinator in Sacramento.
Generally, when a species composition is not generated, landings
are categorized as unknown rockfish. If the unsampled category
is the unspecified rockfish market category, landings are left
in this category. If unsampled landings are in the widow rockfish,
thornyhead, bocaccio, or Pacific ocean perch market categories,
they are treated as pure landings that contain only their respective
species. The PacFIN data are updated as landing reports become
more complete and are replaced with the results from the annual
estimates when these become available.
4.7 Acknowledgments
We would like to thank Bill Lenarz, Frank
Henry, the staff at the MFSU in Long Beach, Connie Ryan, Bernice
Hammer, John Geibel, Larry Quirollo, Bob Leos, Becky Ota, Rachael
Miller, and Cat Talbot for their help, without which this chapter
would never have been completed.
4.8 Citations
Bence, J. R., and J. E. Hightower. 1990.
Status of bocaccio in the Conception/Monterey/Eureka INPFC areas
in 1990. In Pacific Fishery Management Council, Status
of the Pacific coast groundfish fishery through 1990 and recommended
acceptable biological catches for 1991: Stock assessment and fishery
evaluation, Volume 2, Appendix J, p. J1-J65. (Available from
Pacific Fishery Management Council, 2130 SW Fifth Avenue, Suite
224, Portland, Oregon 97201.)
California Department of Fish and Game
(CDFG). 1992. Final Bulletin Tables No. 52. Unpubl. manuscr.,
200 p. (Available from California Department of Fish and Game,
411 Burgess Drive, Menlo Park, CA 94025.)
Clark, G. H. 1935. Logs on California
trawlers. California Department of Fish and Game Fisheries Bulletin
44:37-43. (Available from California Department of Fish and Game,
411 Burgess Drive, Menlo Park, CA 94025.)
Cochran, W. G. 1977. Sampling techniques,
3rd edition. John Wiley & Sons, New York,
428 p.
Conner, G., and nine coauthors. 1952.
The commercial fish catch of California for the year 1950 with
a description of methods used in collecting and compiling the
statistics. California Department of Fish and Game Fisheries
Bulletin 86:1-120. (Available from California Department of Fish
and Game, 411 Burgess Drive, Menlo Park, CA 94025.)
Ernst and Young. 1989. Feasibility study
report for the marine fisheries statistical system. Unpubl. manuscr.,
105 p. (Available from California Department of Fish and Game,
411 Burgess Drive, Menlo Park, CA 94025.)
Goodrich, M. 1988. California Department
of Fish and Game information systems section, trawler log system.
Unpubl. manuscr., 180 p. (Available from California Department
of Fish and Game, 411 Burgess Drive, Menlo Park, CA 94025.)
Groundfish Coordination Unit (GCU). 1995.
California cooperative commercial groundfish survey sampling
manual. Unpubl. manuscr., 72 p. (Available from California Department
of Fish and Game, 411 Burgess Drive, Menlo Park, CA 94025.)
Nitsos, R. J. 1965. Pacific Marine Fisheries
Commission (PMFC) Annual Reports, Nos. 16-17, p. 55-60. (Available
from California Department of Fish and Game, 411 Burgess Drive,
Menlo Park, CA 94025.)
Sen, A. R. 1984. Sampling commercial
rockfish landings in California. U.S. Dep. Commer., NOAA Tech.
Memo. NMFS-SWFC-45, 95 p.
Sen, A. R. 1986. Methodological problems
in sampling commercial rockfish landings. Fish. Bull., U.S. 84:409421.
Tomlinson, P. K. 1977. Rockfish sampling
plan. Unpubl. manuscr., 10 p. (Available from National Oceanic
and Atmospheric Administration, National Marine Fisheries Service,
Southwest Fisheries Science Center, 8604 La Jolla Shores Dr.,
La Jolla, CA 92038.)
U.S. Department of Commerce (USDOC). 1992. Marine recreational fishery statistics survey, Pacific Coast, 1987-1989. Current Fishery Statistics, No. 9205. Washington, D.C., 367 p.