101 
National Marine 
Spencer F. Baird V 
Fisheries Service 
Fishery Bulletin 
First U.S. Commissioner S 
NOAA 
fy- established in 1881 
of Fisheries and founder mSjK 
of Fishery Bulletin iMy 
Horizontal and ¥ertical movements of longfin 
makos itsurus paucm} tracked with satellite- 
linked tags in the northwestern Atlantic Ocean 
Robert E. Hueter (contact author)’ 
John P. Tyminski’ 
John J. Morris’ 
Alexei RuIe Abierno^ 
Jorge Angulo Valdes^'® 
Email address for contact author: rhueter@mote.org 
' Center for Shark Research 
Mote Marine Laboratory 
1600 Ken Thompson Parkway 
Sarasota, Florida 34236 
2 Centro de Investigaciones Marinas 
Universidad de la Habana 
Calle 16, No. 114 e/ Ira y 3ra 
Miramar, Playa, La Habana CP 11300, Cuba 
3 School of Natural Resources and Environment 
University of Florida 
P.O. Box 116455 
Gainesville, Florida 32611 
Abstract— The longfin mako (Isurus 
paucus) is a poorly studied oceanic 
shark taken in fisheries throughout 
its worldwide range in temperate 
and tropical waters. Satellite-linked 
tags were deployed to investigate 
the movements of 2 mature males, 
one tagged in the northeastern Gulf 
of Mexico (GOM) and the other off 
northern Cuba. Horizontal tracks 
estimated by using likelihood meth- 
ods were similar for these sharks; 
comparable movements were docu- 
mented from the GOM, through 
the Straits of Florida and the Ba- 
hamas, and into the open Atlantic 
Ocean where they converged on the 
Mid-Atlantic Bight. Depth and tem- 
perature ranges were 0-1767 m and 
4.0-28.8°C. A diel pattern of vertical 
movement was evident for both in- 
dividuals, along with regular forays 
from cold daytime depths to warmer 
near-surface waters, possibly as an 
adaptation for thermoregulation. 
The vertical movements of longfin 
makos allow them to exploit verti- 
cally migrating prey but these move- 
ments increase their vulnerability to 
pelagic longlining. The horizontal 
movements of these sharks reveal 
the limited benefit of areas current- 
ly closed to pelagic longlining off 
the southeastern United States and 
also indicate the connectivity of U.S., 
Cuban, Mexican, and Bahamian wa- 
ters for this species. Because of the 
vulnerability of longfin makos to 
overexploitation, improved biological 
information is needed for accurate 
stock assessments and appropri- 
ate management and conservation 
measures. 
Manuscript submitted 15 April 2016. 
Manuscript accepted 29 November 2016. 
Fish. Bull.: 115:101-116 (2017). 
Online publication date: 20 December 2016. 
doi: 10.7755/FB.115.1.9 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The shark genus Isurus comprises 
2 species with similar morphologi- 
cal features, the shortfin mako (I. 
oxyrinchus) and the longfin mako 
(I. paucus) (Compagno, 2001). The 
longfin mako is a global oceanic spe- 
cies that inhabits both tropical and 
subtropical waters (Compagno, 2001) 
but also ranges into temperate seas 
(Queiroz et ah, 2006; Bustamante et 
ah, 2009; Mucientes et ah, 2013). In 
the western Atlantic Ocean, the long- 
fin mako has been documented in the 
Gulf Stream off the eastern United 
States, off Cuba’s northern coast, as 
far south as southern Brazil (Com- 
pagno, 2001), and as far north as 
Georges Bank (Kohler et ah, 1998). 
In the Gulf of Mexico (GOM), long- 
fin makos have been observed in- 
frequently but have been reported 
in the northern GOM off the Mis- 
sissippi River and south of Panama 
City, Florida (Killam and Parsons, 
1986) and in the southern GOM off 
Tabasco, Mexico (Wakida-Kusunoki 
and de Anda-Fuente, 2012). Despite 
its large size (to at least 417 cm in 
total length [TL]; Gilmore, 1983), 
the longfin mako is an understudied 
species, partly because of its relative 
rarity, its pelagic nature, and observ- 
ers’ confusion with its congener, the 
shortfin mako (Castro, 2011). 
The longfin mako is not directly 
targeted in any fishery, but is taken 
as bycatch throughout its range in 
tropical and temperate waters by 
pelagic longline fisheries that tar- 
get swordfish {Xiphias gladius), tuna 
species {Thunnus spp.), and other 
shark species (Reardon et ah, 2006; 
Mucientes et ah, 2013; Fredou et ah, 
2015). In a study of shark bycatch in 
the small-scale, pelagic longline fish- 
ery of northwest Cuba, Guitart Man- 
day (1975) reported that the longfin 
mako was the sixth most common 
shark by weight of the 11 shark spe- 
cies reported; a more recent study of 
this fishery ranked the longfin mako 
higher in landings (Aguilar et ah, 
