190 
Fishery Bulletin 107(2) 
seasonal catchability estimates and 
trap reductions under the TCP. This 
relationship, when the fishing effort 
is by passive fishing units (e.g., traps, 
longlines, gillnets, etc.), has also been 
reported for the spiny lobster fisher- 
ies of Australia (Groeneveld et al., 
2003), Brazil (Ehrhardt, 2005), and 
Nicaragua (Ehrhardt (2005); crawfish 
(Romaire and Pfister, 1983; Fouilland 
and Fossati, 1996); and cod (Angelsen 
and Olsen, 1987). Figure 4 indicates a 
significant increase in the fraction of 
the stock that was taken per trap-day 
as the number of interacting traps was 
reduced from about 851,000 to about 
550,000. It is observed that during 
the period of the TCP, the 1991-92 to 
the 2002-03 fishing seasons, the fish- 
ing effort expressed in traps-days be- 
came at least 50% more efficient due 
to changes in trap catching efficiency. 
This increase was independent of the 
decreasing stock abundance levels. 
Financial performance 
CD 
-Q 
E 
0.18 
0.16 
0.14 
0.12 
0.1 
0.08 
0.06 
0.04 
0.02 
0 
» Observed CPUE 
- □ - - Expected CPUE 
Dec -89 Apr-91 Aug-92 Jan-94 May-95 Oct-96 Feb-98 Jul-99 Nov-00 Mar-02 Aug-03 
Fishing season 
Figure 3 
Observed (•) Florida seasonal spiny lobster (Panulirus argus) catch in 
number of lobsters per trap per day per trip (CPUE) corrected by soak- 
ing time in days and expected (O) CPUE obtained by fitting the depletion 
model to the observed data during the 1991 to 2002 fishing seasons. 
Fishing seasons are from August to April. 
Fishery-wide analysis The fishery-wide financial perfor- 
mance was assessed based on monthly revenues using 
the costs per trap day per trip and the average monthly 
value paid per kilogram of lobster landed in the 2002-03 
season estimated from the trip ticket database. The 
average seasonal direct costs and indirect costs per trip 
were transformed to a per-trap-day-per-trip condition 
based on the average number of 347.8 (standard devia- 
tion=213) traps pulled per trip and 78 trips per season 
reported in the 2003-04 survey. Therefore, it was pos- 
sible to judge the consequences of the increases in the 
catching efficiency of the traps due to the TCP and the 
decreasing trend in stock abundance observed in the 
period of analysis. 
Analysis of the different scenarios considered in this 
study indicates highly significant differences regard- 
ing the seasonal dissipation of revenues as a function 
of the number of traps used in the fishery. However, 
such dissipation is dramatically influenced by the lower 
catchabilities observed when a large number of traps 
are deployed in the fishery. For example, Figure 5A 
shows the monthly revenues of the 1991-92 scenario 
of high abundance and lowest q fishing season, prior 
to the TCP implementation, and the 2001-02 fishing 
season with the lowest abundance and highest q. The 
figure indicates that revenues dissipated quickly and 
became negligible by March in both cases. The total 
seasonal revenue per vessel was $17,701 and $13,405 
for the 1991-92 and 2001-02 fishing seasons, respec- 
tively. Thus, although a much larger stock abundance 
was present during the 1991-92 fishing season relative 
to the 2001-02 season, the less efficient traps at that 
time generated a catch per trap day per trip that did 
IV 
o 
UJ 
C/5 
CO 
~o 
Cl 
CO 
0.24 -I 
0.22 - 
0.2 - 
• • 
•• t 
CO 
O 
0.18 - 
0.16 - 
0.14 - 
0.12 
400,000 
600,000 800,000 
Number of traps 
1 , 000,000 
Figure 4 
Trend of decreasing catchability (measured in 
trap days) with increasing number of traps in 
the spiny lobster (Panulirus argus) fishery in 
Florida from 1991 to 2002 fishing seasons. 
not contribute significantly to the total revenues. If the 
catchability coefficient of 2001-02 could have been ap- 
plied to the stock abundance available in the 1991-92 
season, the total annual revenue per vessel would have 
been $38,654, or about 2.18 times larger than that 
which was actually obtained. 
In the scenario under which the TCP would not have 
been established, very small revenues would have been 
generated by the fishery. This case compares the rev- 
enue conditions for the 2001-02 fishing season abun- 
