Hueter et al.: Horizontal and vertical movements of Isurus paucus in the northwestern Atlantic Ocean 
105 
38°N 
42°N 
40'’N 
68°W 
36°N 
— I — 
70°W 
34''N 
itic Ocean 
32”N 
78°W 
76°W 
74°W 
15 
10 
km 
— I — 
72'W 
78°W 76°W 74“W 72°W 70°W 68°W 
78°W 76°W 74‘>W 72‘>W 70‘=W 68°W 78°W 76°W 74°W 72°W 70'W 68°W 
Figure 2 
Locations of warm water from the Guif Stream during late June and July and estimated positions of longfin 
makos {Isurus paucus) tracked with satellite-linked tags in the northwestern Atlantic Ocean. (A) Track of 
the first shark, LFBJl, from 29 June to 5 July 2012 in relation to sea-surface temperature (SST) for 2 July 
2012. (B) Track of LFMl for the period 21-27 July 2012 in relation to SST for 24 July 2012. (C) Track of the 
second shark, LFM2, from 29 June to 5 July 2015 in relation to SST for 2 July 2015. (D) Track of LFM2 for 
the period 9-15 July 2015 in relation to SST for 12 July 2015. Blue and white circles represent positions in 
June and July, respectively. Red triangles mark the locations where the pop-up tag was released. The gray 
lines represent the 1000-m and 4000-m depth contours. 
LFMl remained within warm Gulf Stream waters and 
largely off the continental shelf 100-400 km from the 
coasts of Delaware, Maryland, and Virginia (Fig. lA; 
Fig. 2, A and B). The northernmost position of the track 
(39.25°N, 72.83°W) was reached on 11 July. The total 
distance of the MLT was 6809 km, representing a mean 
movement rate of 75.7 km/d. 
The MLT for LFM2 displayed movement from the 
northern coast of Cuba into the Straits of Florida in 
the latter half of February, followed by movements 
into waters of the Bahamas by early March (Fig. IB). 
Then LFM2 remained in Gulf Stream waters between 
Grand Bahama Island and southeast Florida for a pe- 
riod of about 3 weeks. By late March and early April, 
