12 
Fishery Bulletin 11 6(1) 
300 - 
250 
200 
150 
100 - 
50 
Ba 1- 
-!- 1 - 1 - 1 - 1 - 1 — 
Jan Feb Mar Apr May Jun 
Jul 
Month 
300 - 
250 
200 
150 
100 
50 
0 
B 
Aug Sep Oct Nov Dec 
-— Median 
] 25%-75% 
— nonoutlier range 
□ 
-!-!- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 
Year 
Figure 1 
Variation between (A) months and (B) years in estimated incidental catch per 
unit of effort of common dolphinfish (Coryphaena hippurus ) and pompano dol- 
phinfish (C. equiselis) in the eastern Pacific Ocean off Mexico during 2004- 
2013. The thick black line is the median, the box displays the 25% and 75% 
quartiles, and the whiskers extend 1.5 times beyond the interquartile range. 
(24 fish) were reported during December for this size 
class (Fig. 3A). 
Highest incidental catch occurred during 2004, 
where 40% (2121), 28% (5977), and 22.50% (6453) of 
total fish for the 10-year period were caught for the 
small-, medium-, and large-size classes, respectively. 
Lowest annual incidental catch occurred during 2008 
for the small-size class (0.50% of total fish for this size 
class, 26 fish) and the medium-size class (2.40% of to¬ 
tal fish for this size class, 507 fish), and during 2011 
for the large-size class (2.70%, 782 fish) (Fig. 3B). 
Summary of environmental variables 
A wide range of SST, chl-a concentration, and SSH val¬ 
ues was found in the study area, during the 10-year 
period. Maximum, minimum, and mean values for SST 
were 33.12°C, 12.54°C, and 24.54°C (SD 4.28). Chl-a 
concentration ranged from 0.02 to 38.76 mg/m 3 , with a 
mean of 0.51 mg/m 3 (SD 1.47). Lowest SSH value for 
the study period was -0.30 m, with a maximum of 0.39 
m, and a mean of 0.02 m (SD 0.07). 
Environmental and spatial preferences per class size 
Residuals vs. fitted values in scatter plots for fitted 
polynomial models showed no clear pattern for any 
of the environmental variables, and the histograms 
of the residuals were apparently normal (results not 
shown) in all cases, which suggests good fits (Zuur et 
ah, 2009). Large and small dolphinfish incidental catch 
per unit of effort (ICPUE) peaked at ~24°C, whereas 
medium-size fish ICPUE peaked at ~26°C (Fig. 4A). 
Most fish were caught in waters with low (<0.15 mg/ 
m 3 ) chl-a concentrations, but 2 interesting peaks in 
catch occurred for small- and medium-size fish in wa- 
