0476 ss rev_ren Part B 020507

SUPPORTING STATEMENT
SOUTHEAST REGION OFFICE SOCIOECONOMIC SURVEY OF GULF SHRIMP
FISHERMEN
OMB CONTROL NO.: 0648-0476

B. COLLECTIONS OF INFORMATION EMPLOYING STATISTICAL METHODS
1. Describe (including a numerical estimate) the potential respondent universe and any
sampling or other respondent selection method to be used. Data on the number of entities
(e.g. establishments, State and local governmental units, households, or persons) in the
universe and the corresponding sample are to be provided in tabular form. The tabulation
must also include expected response rates for the collection as a whole. If the collection has
been conducted before, provide the actual response rate achieved.
The population of interest is all the vessels fishing for penaeid shrimp in the federal waters of the
Gulf of Mexico, i.e. off the States of Texas, Louisiana, Mississippi, Alabama and Florida, during
one calendar year. In contrast to prior efforts, there will be an excellent sampling frame available
for this and future survey efforts, because starting in 2003 these vessels were required to have a
federal permit. This sampling frame was not available earlier, which explains some of the
difficulties the prior surveys encountered with successfully contacting respondents.
For the 2007 survey effort, the sampling frame will consist of all fishermen holding a federal
shrimp permit anytime during 2006. Their contact information will be updated with the help of
the new, ongoing moratorium permit application database. The population is separated into two
subgroups, active and inactive vessels in the Gulf shrimp fishery. The groups will be identified
with the help of the dealer database, which is a mandatory reporting requirement and hence
should cover all shrimp transactions. This information will be available by April, 2007.
Starting March 27, 2007 any shrimp vessel fishing in the federal waters of the Gulf of Mexico
will need to have a moratorium permit, and October 26, 2007 is the final day to apply for a
moratorium permit. The survey efforts in 2008 and 2009 will rely entirely on this new database
as the sampling frame and this should be a further improvement.
In total, we will sample 825 vessels in order to arrive at 600 completed surveys based on an
expected overall response rate of 73%. Within the active group of vessels, we are aiming for 500
completed surveys, as most analyses will focus on this group. Based on other required surveys
and reporting efforts in the region, we might expect a response rate somewhere between 70-90%.
Assuming an 80% response rate will require contacting 625 vessels. Inactive vessels are clearly
less important than the active ones for the majority of analyses. Yet little is known about these
vessels in this fishery, so in order to explore this group and understand possible biases, we aim to
collect 100 completed surveys from this group. Given that these vessels are not fishing for Gulf
shrimp, we expect a larger segment of them to be permanently out of the industry and hence
difficult to reach or not motivated to participate in our survey. Under these conditions we believe
assuming a 50% response rate is more appropriate; requiring us to sample 200 vessels. In total,
we will sample 825 vessels in order to arrive at 600 completed surveys, leading to an expected
overall response rate of 73%.
1

Due to the management and political importance attributed to delineation by state, we will
stratify each of the above groups of vessels by state. Within each stratum we will randomly
sample vessels in proportion to each stratum’s weight in the population. At this time the final
sampling frame with stratification is not yet available. The final sampling frame will use all the
information available just prior to the survey implementation. The previous, complex sampling
design proved problematic in light of the low response rate. By sticking to a simple, straight
forward design, we hope to avoid potential problems. A much better sampling frame and up-todate contact information will also help.
Currently, the closest estimate of the final sampling frame consists of 2,666 vessels. Table 1
(attached below) breaks down this preliminary sampling frame into the strata, offers some
descriptive data for the vessels in each, and generates the tentative number of respondents
sampled and surveys completed in each. Of the 2,666 vessels, 1,806 were active in the Gulf
shrimp fishery during 2005. Over two thirds of the active vessels hail from Texas and Louisiana.
There is significant variation within the industry across various variables, but none seems to
further divide the population into discrete groups (offering no advantage of further stratification).
These numbers are unlikely to change much in 2006. For the 2008 and 2009 efforts, the actual
number of permit holders and active participants in the fishery can change due to new entrants
(until 10/07 if they qualify), owners and vessels leaving the fishery, or changes in vessel
ownership and fisheries in which that vessel engages.
As mentioned in the introduction, the prior collections have met with little success. Due to a
variety of factors, it was difficult to contact the fishermen. Further, fishermen outside of Texas
did not cooperate with the effort. This forced us to fundamentally re-evaluate our approach and
has led to the substantial changes requested in this document. The response rates for the
voluntary, in-person interview data collections in Texas and the rest of the Gulf are reported in
Table 2 (attached below).
2. Describe the procedures for the collection, including: the statistical methodology for
stratification and sample selection; the estimation procedure; the degree of accuracy
needed for the purpose described in the justification; any unusual problems requiring
specialized sampling procedures; and any use of periodic (less frequent than annual) data
collection cycles to reduce burden.
Separately for active and inactive vessels, we will assign each vessel a random number generated
by an advanced statistical program ( Statistical Analysis System (SAS) or equivalent). We will
then stratify the population by state and sort by the random numbers. In each stratum, a number
of vessels at the top of the list will be proportionally sampled (see also table 1). Overall, the
approach is equivalent to simple random sampling (proportional) within each strata and should
require only simple adjustments to the inclusion probabilities used for the estimation of
population means and other aggregate statistics (if non-response is significant or skew across the
strata). In the few cases where active and inactive boats might be collectively analyzed, the
estimates will need to take account of the different inclusion probabilities of these two
subpopulations.
The owner of each vessel selected will be contacted by mail. The letter will contain a cover
letter, instructions, the two page survey instrument and a return envelope. They will be asked to
2

return the completed survey instrument to us in the enclosed, pre-paid envelope. If no response is
received within 30 or 60 days, up to two further letters will be sent (including additional survey
instruments). Finally, we will attempt to contact the remaining non-responders by phone shortly
after the third mailing and urge them to return the survey. Information will not be collected
during the phone call, and a further survey instrument will be sent – by mail or email – if
requested.
After data entry, verification and cleaning, descriptive statistical analysis will be conducted on
the relevant variables collected (costs and profits). Results will be reported by State and by other
relevant post-stratifications (such as size of operation). The accuracy for the population level
totals and means of the important variables should exceed the standard +/- 5% confidence
interval at a 95% significance level. This level of accuracy would be the best ever collected on
these variables in the shrimp fishery. Given the overall uncertainty inherent to policy
assessments of economic conditions in fisheries and given the quality and accuracy of other data
used, the standard accuracy should suffice. The accuracy of the results for larger subpopulations
(>100 observations) will likely be significant as well.
Since the method being employed is new in this fishery; statistically meaningful data is urgently
needed by the Council; and developments in this fishery have recently been occurring fast and
are leading to large economic impacts, this data collection will be repeated annually for the first
two or three years. The use of periodic instead of annual collection will be considered in the
future. The burden on the public will depend on how frequently significant changes occur in this
industry. Optimally, an annual survey with an adaptive sampling design could minimize this
burden and yet retain the flexibility to generate timely and accurate data. Such advantages would
need to be weighed against the administrative complexity and the required resources.
3. Describe the methods used to maximize response rates and to deal with nonresponse.
The accuracy and reliability of the information collected must be shown to be adequate for
the intended uses. For collections based on sampling, a special justification must be
provided if they will not yield "reliable" data that can be generalized to the universe
studied.
The central approach to maximizing the response rate is to make answering a very concise and
simple survey a requirement for future permit renewal. The first cover letter will politely
emphasize this point. The second and third reminder letters will be more explicit. Finally, the
telephone call will also explain the consequences of not complying. The call has the further
advantage of being a different mode of contact and should discover nonresponse due to an
incorrect address. Given the potential loss of permit, we expect compliance from all fishermen
wanting to continue to fish for shrimp in federal waters. The behavior by those who have left the
fishery by the time of the survey, or are planning to leave it before their current permit expires,
will not be influenced by the implicit threat. This is why we assume a lower response rate for
inactive vessels. Since the data will be used primarily for assessments and predictions about
future developments, under-reporting by individuals leaving the fishery is less problematic.
An excellent sampling frame, with recently updated contact information (through the ongoing
moratorium permit registration), will help to reduce the non-contact component of non-response.
Also, the study population has shifted somewhat; from offshore Gulf shrimp vessels to vessels
fishing in federal waters. Vessels fishing federal waters are a subset of all offshore shrimp
3

fishing vessels and operate further from shore. This leads to an increase in the average size of
surveyed operations, which should result in a higher ratio of “professional” fishermen who might
be more likely to return a survey. At the conclusion of the survey, we will contact port agents
(local federal employees who collect data and report from a limited area) and ask them for any
information on non-responding vessels/individuals. Should non-response be a significant factor,
we might even ask port agents to inquire themselves, and/or we will debrief a few (<10)
individuals about reasons for not responding in order to establish potential non-response biases.
Beyond the above, we will take every action available to us to facilitate completing and returning
the survey by the fishermen. General survey design techniques (Dillman method) and experience
from the previous surveys will guide us. Noteworthy actions include:
•
•
•
•

Timing of the survey during the slow shrimp fishing season (winter and spring) and
following tax time, when business records are being consulted and financial concerns are
“top of mind.”
Conducting outreach in advance of the survey, including on NMFS and Council websites
and through meetings, radio, shrimp association newsletters and the grapevine.
Creating and disseminating together with the survey effort-specific outreach material (see
Figure 1 for an example of the outreach material).
Using plain language and translating the survey into “language” spoken by Gulf shrimp
fishermen.

The statistical design and size of this sample survey will allow for valid generalizations of the
results to the population and larger subpopulation levels. The anticipated accuracy of the results
is discussed in more detail in the last question (part B, question 3).
4. Describe any tests of procedures or methods to be undertaken. Tests are encouraged as
effective means to refine collections, but if ten or more test respondents are involved OMB
must give prior approval.
We have drawn extensively on the experience generated by the very similar annual cost data
collection effort in the Gulf finfish fishery (OMB Control No.: 0648-0016). Beyond consulting
with Gulf shrimp fishery experts about the survey instrument and design (see questions 4 and 8),
we have sent the survey instrument for review to port agents throughout the Gulf. The port
agents’ proximity and familiarity with the Gulf fishery, especially their extensive contact with
fishermen, makes their recommendations very valuable. They have advised us on the feasibility
of collecting this data, the expected response, and the language on the survey instrument and
raised useful questions.
5. Provide the name and telephone number of individuals consulted on the statistical
aspects of the design, and the name of the agency unit, contractor(s), grantee(s), or other
person(s) who will actually collect and/or analyze the information for the agency.
Individual consulted on the statistical aspects of the design:
James R. Waters, Ph.D.
National Marine Fisheries Service
Southeast Fisheries Science Center
Beaufort Laboratory
4

(252) 728–8710
Persons who will actually collect and analyze the information:
Christopher Liese, Ph.D.
National Marine Fisheries Service
Southeast Fisheries Science Center
Social Science Research Group
(305) 365-4109
Michael D. Travis, Ph.D.
National Marine Fisheries Service
Southeast Regional Office
Social Science Branch
(727) 551-5722

5

Table 1: Sampling Frame, Sampling Strata, Population Characterization, Response Rate and Sample Size
State
Active
(68%)

Population

Population

Vessel
Size

Vessel
Refridg.

Vessel
Construct.

Catch

Catch

Catch

Price

Large*

Use Ice

Steel Hull

Total
51,415
58,289
53,624
44,177
41,659
36,618

Small
Vessel
8,062
33,077
10,419
13,143
8,454
-

Large
Vessel
53,209
77,627
64,752
62,310
45,851
36,618

96%
57%
80%
63%
89%
100%

26%
74%
49%
48%
33%
12%

94%
74%
87%
65%
33%
80%

51,722

24,771

58,808

TX
LA
MS
AL
FL
Other

705
546
166
141
223
25

% of
Active
39%
30%
9%
8%
12%
1%

Total

1,806

100%

79%

45%

77%

State

Population

Population

Vessel
Size

Vessel
Refridg.

Vessel
Construct.

Large*

Use Ice

Steel Hull

75%
62%
47%
50%
39%
90%

59%
68%
72%
61%
53%
35%

68%
74%
58%
49%
18%
65%

32
15
7
10
31
6

59%

58%

51%

100

Total

InActive
(32%)
TX
LA
MS
AL
FL
Other

275
128
60
82
263
52

% of
InActive
32%
15%
7%
10%
31%
6%

Total

860

100%

Total

E(Completed
Surveys)

E(Response
Rate)

E(Completed
Surveys)

E(Response
Rate)

Mean of
Mean
3.32
2.19
2.58
2.92
3.12
2.88

195
151
46
39
62
7

0.8
0.8
0.8
0.8
0.8
0.8

2.85

500

627

Note:
* Large = greater 60 foot
E( ) indicates expectation of.

64
30
14
20
62
12
202

Table 2: Past Response Rates

Texas
Rest of Gulf

Sampled

Unreachable

Ineligible

Refused

Completed

1,109
3,257

359
2,001

162
1,344

69
78

38
522

90
57

6

244
189
58
49
78
9

# to be
Sampled

0.5
0.5
0.5
0.5
0.5
0.5

Population

# to be
Sampled

Response
Rate (raw)
25.1%
2.8%

Reachable

Refusal Rate

54.9%
32.8%

29.7%
90.2%

Figure 1: Information material (draft)

Why we need
to Know

Your information is treated as
confidential.

Your information will not be released.

Fishery
Managers
need
up-to-date
information about the economic health of
the Gulf shrimp fishery in order to make
sound decisions, such as producing Fishery
Management Plan Amendments that take
account of the economic situation and
contribution of this important industry.

We are interested only in
industry-wide economic indicators.

Your information will be
combined with the information from
other fishermen.

Most importantly, we, the scientists collecting and analyzing this data,
need to know the total profit (or loss) generated by the industry. This
information enables us to calculate the value of the shrimp fishery to
fishermen and to the nation. Other things we report to the Council, decision
makers, fishermen and the public include:
• Income shares of owners and crew in the industry
• Overall capital invested and total debt in the industry
• Financial risk the industry is exposed to
• The impact of fluctuating fuel and ice prices on the industry

With statistical methods
we will estimate industry averages and
industry totals.

There is no simple way to explain why we are asking the particular
questions in the survey, since some business and accounting skills are
needed. Our best attempt is inside this brochure. It looks more complicated
than it is!

The results of this research will be
made available to you.
7

Annual Report of the Gulf Shrimp Fishery

Why we want to Know:

Industry Income Statement:
0

100 million

200 million

$

300 million

Total Shrimp Revenue (known)
Variable Costs

Fixed Costs

Annual Costs

Depreciation

Labor Costs

⇒

Economic understanding of the industry

"Pure" Profit

⇒

To create models that predict the impact
of proposed regulations
How is the industry affected by input
price changes? What is the crew's
share of the industry?

Profit

Trip Costs

Return to
Owners' Time

Return to Owners'
Net Equity

Depreciation

Overhead

Vessel &
Gear Costs

Crew

Captain

Fuel

Ice

Other

Owners'
captain's pay
and salaries

Loan
Principal
Repaid

Investment
in Vessel

⇒

(Q12a, Q14, Q15)

•

•

Q1

Q2

Q3

Q5

Q6

Q2 + Q9

•

•

}

Q13c

(Q8)
Q10

Q7

Most Important Result:

Annual Income in
Fishery (labor's share)

+

Annual Income in Fishery (owner's share)

⇒

Q# is Survey Question
collecting this information
* ( ) calculated indirectly from survey data

Overall Income can be used to calculate
the VALUE of the shrimp fishery to
fishermen and the nation. Very important
for Resource Management.

Industry Balance Sheet
0

0.5 billion

1 billion

1.5 billion

$

Total Capital Invested in Vessels (at Purchase Price) (Q12b)

Capital Stock (in Vessels at Market Value) Q12a

Loans Q13a

Insured Q11

Net of Cumulative Depreciation (-) and Re-Investment (+)

Net Equity of Owners

Uninsured

8

⇒

How much capital is invested in the
industry?

⇒

How in debt is the industry?

⇒

How much risk is the industry exposed
to?