188 
Fishery Bulletin 107(2) 
where n represents the number of months, U t represents 
CPUE in month t , and a\ was fixed to achieve a coef- 
ficient of variation of 20% in log space — a percentage 
that was adopted to represent the likely response of the 
change in q to trap reductions. 
The monthly CPUE was measured in numbers of 
spiny lobsters caught per trap day per trip, where a trip 
is defined as the day when a set of traps was serviced. 
The difference between trips represents the effective 
soak time measured in days. Therefore, any seasonal 
change in catchability would refer directly to a per- 
trap-day condition defined between fishing trips. One 
important consideration in the preparation of the data 
to fit the model using the objective function (Eq. 7) was 
the realization that soaking times may vary throughout 
the fishing season, with an increasing trend expected 
as the fishing season progresses and local population 
abundance is depleted. The soaking time may also vary 
among fishing seasons as a consequence of differences 
in seasonal abundance. Therefore, if these variations 
in soaking times occur, the catch per trap day per trip 
would have to be standardized to the changing seasonal 
soaking time. 
Financial performance under the trap reduction program 
The financial analysis to assess the results of the TCP 
was based on monthly and seasonal revenue estimations 
that required information on the average unit price paid 
for product landed per trap day per trip, and the cost 
per trap day per trip incurred in the realization of the 
landings. The average monthly price paid per kilogram 
of spiny lobster landed was obtained from the trip ticket 
database provided by the FWC for each of the fishing 
seasons covered in this analysis (1991-2002). The aver- 
age cost data (indirect and direct) was obtained from a 
census carried out from February 2003 through January 
2004 sponsored by the FWC, which included interviews 
of 221 fishermen operating in the spiny lobster fishery. 
The information collected in the 2003-04 cost survey 
included the general characteristics of the fishermen 
and their historical involvement in the multispecies 
fisheries associated with spiny lobster in South Florida. 
Other data important to this analysis provided by the 
FWC were the fraction of the total effort dedicated to 
spiny lobster operations, as well as the variable and di- 
rect costs associated with the fishermen’s participation 
in the spiny lobster fishery. The variable cost informa- 
tion per trip included fuel and oil, bait, ice, food and 
supplies, and other costs. The direct cost data used in 
the analysis consisted of the value of the vessel and 
the age of the vessel so that vessel depreciation could 
be analyzed, annual dockage cost, trap costs (including 
repairs and labor), principal and interest on loans (IP), 
and protection and indemnity (PI) payments. The aver- 
age costs for docking, IP, and PI included the zero costs 
reported by many fishermen who used dock facilities 
without cost or did not have debts on loans or insur- 
ance, and as such these were considered in the average 
direct cost estimation. 
The cost analyses conducted in this study considered 
that the direct costs related to vessel depreciation, dock- 
age, and vessel repairs should be proportionally distrib- 
uted between the spiny lobster fishing operations and 
other fishing operations carried out by the same vessels. 
In the survey, the combined data for the entire fishery 
provided an average of 66% of fishing time allocated to 
spiny lobster. This proportion, therefore, was applied 
to the direct cost components pertaining to docking, 
IP and PI payments, and vessel repairs as directed to 
spiny lobster fishing on a fishery-wide scale. Similarly, 
the regional spiny lobster direct costs for the segregated 
areas were estimated by the average percent participa- 
tion in spiny lobster fishing in each region declared in 
the survey. 
The average total number of trips carried out sea- 
sonally per vessel and the average number of traps 
serviced per trip necessary to estimate costs on a per- 
trap-day-per-trip basis were also obtained from the 
survey data. 
The vessel depreciation life was estimated at 18 
years with data from the 2003-04 FWC survey. The 
age structure of the fleet, generated from the 2003- 
04 survey data, indicated that a large fraction of the 
vessels are in or above the 16-20 year class range 
that includes the depreciation life span of the vessels. 
Therefore, the cost analysis considered only the cost 
associated with the fishery-wide average payments on 
principal and interest that fishermen were paying for 
their vessels since most of the vessels are already paid 
off. The seasonal direct costs were converted to a per- 
trip basis by dividing by the average number of spiny 
lobster fishing trips. 
The financial analyses were assessed on a fishery- 
wide and regional basis. Thus, it was necessary to con- 
sider the seasonal changes in stock abundance, and 
the dynamic changes in the catchability coefficient that 
occurred as a consequence of the trap reduction sched- 
ule. Because the cost data pertain only to the 2003-04 
fishing season, the financial analyses were designed as 
case scenarios, where the CPUE was a function of the 
average population abundance, and the value of the 
CPUE was assumed for a fishing season of reference. 
In order to generate the catch per trap day per trip 
scenarios, results from the application of the assessment 
methods (Eqs. 1-7) were used as follows: 
1 The average monthly abundance for the season with 
the highest abundance (1997-98), the lowest abun- 
dance (2001-02), and an intermediate abundance 
were used to estimate seasonal catch per trap day 
per trip according to Equation 3. 
2 The catchability coefficient, q, required for the esti- 
mation of the catch per trap day per trip in Equation 
3 was selected for the following conditions: a) low 
q — when the number of traps was high (1991 fish- 
ing season); b) high q — when the number of traps 
was low (2001 fishing season); and c) intermediate 
q — corresponding to the trap levels achieved by the 
TCP during the 1997-98 season. 
