Marm-Enriquez and Muhlia-Melo: Environmental and spatial preferences of Coryphaena spp. 
15 
14,000 - 
12,000 - 
10,000 - 
8,000 - 
6.000 
4.000 
2,000 - 
0 - 
20,000 
& Small 
□ Medium 
■ Large 
4 - i ll hi 
10 14 18 22 26 
15,000 - 
10,000 - 
5,000 
18 22 26 30 34 
Latitude ("N) 
D 
i H ^ Jig i ^ — 
14,000 
12,000 
10,000 H 
8,000 
6,000 
4,000 
2,000 
0 4 
14,000 -i 
12,000 - 
10,000 - 
8,000 - 
6,000 
4,000 - 
2,000 - 
B 
14,000 - 
12,000 - 
iiilL 
-126 -117 -108 -91 
JL 
-117 -108 -99 -93 
Longitude (°W) 
SST (°C) 
T^ 
0.05 0.65 1.25 1.85 
Chl-a (mg/m 3 ) 
2.45 
0 J 
E 
-0.15 
0.05 0.15 0.25 0.35 
SSH (m) 
Figure 5 
Spatial and environmental preferences of dolphinfish (Coryphaena spp.) caught by the purse-seine 
fleet off Mexico in the Pacific Ocean from January 2004 to June 2013: (A) latitude; (B) longitude; 
(C) sea-surface temperature (SST); (D) chlorophyll-o concentration (chl-a); and (E) sea-surface height 
(SSH). Note the difference in the scale of the y-axis in graph D. 
coordinates on a map (i.e., “centroids”), areas with high 
dolphinfish ICPUE moved north westward during the 
months of April-May, and from south eastward during 
September-October (Fig. 7). 
Mean monthly latitudes of high catch quadrants and 
position of 25°C isotherm at 120°W showed a similar 
pattern, although a 1-month lag was visible for the 
peaks of the 2 curves: maximum latitude for the iso¬ 
therm occurs 1 month later than the maximum mean 
latitude of the quadrants (Suppl. Fig. 1) (online only). A 
high r of 0.84 was found, which was significantly dif¬ 
ferent from 0 (P<0.05). 
Discussion 
Two areas of high dolphinfish ICPUE were present 
in the study area, one on the west coast of the BCP, 
where practically all ICPUE occurs during August (20— 
27°N and 113-116°W), and a second one in an oceanic 
zone (around 10-20°N and 115-125°W), where higher 
ICPUE occurs during May-June. July seems to be a 
month of transition between areas of high catch because 
a large area of relatively high abundance is observed, 
which covers the northern portion of the oceanic area 
and the southern portion of the BCP high catch area 
(Suppl. Fig. 2) (online only). Two of the potential factors 
that determine dolphinfish presence are the occurrence 
of floating objects and variations in SST; unfortunately, 
the relationship of ICPUE with floating objects could 
not be explored because of limited data. In terms of 
environmental factors, such as SST, it is well known 
that the upwelling of subsurface cool waters favors the 
development of the oceanic food web by bringing nutri¬ 
ents into the photic upper ocean layer (Reilly, 1990). 
Along the western coast of the BCP, wind blows paral¬ 
lel to the coast and causes intense upwelling (Zaytzev 
et al., 2003) during March-June because of the Ekman 
transport; these upwelling events can last up to 10 d 
(Walsh et al., 1977; Cervantes-Duarte et al., 1993) and 
are capable of concentrating plankton feeders such as 
the red pelagic crab (Pleuroncodes planipes ), one of the 
main sources of food for dolphinfish and other large 
pelagic fish in this area (Aguilar-Palomino et al., 1998; 
Tripp-Valdez, 2005; Martlnez-Rincon et al., 2009). 
Ortega-Garcla and Lluch-Cota (1996) found a 3-month 
lag between spatial chlorophyll fronts (with peak chl-a 
concentration) and peaks in high abundance of yellow- 
fin tuna (Thunnus albacares). Because yellowfin tuna 
and dolphinfish share habitat to some extent, the same 
~3 month lag could also help to explain high dolphin¬ 
fish abundance in the BCP during August-September, 
