The white shark (Carcharodon carcharias) is a member of Family Lamnidae. It is a widely distributed apex predator inhabiting coastal and pelagic zones from temperate and sub-tropical waters (^{Compagno, 2001}; ^{Weng et al., 2007a}). Juvenile white sharks occur in nearshore waters while adults are wide-ranging (^{Weng et al., 2007b}; ^{Jorgensen et al., 2012}). Adults and subadults are known to perform long migrations, spending considerable time in oceanic waters (^{Boustany et al., 2002}; ^{Bonfil et al., 2010}).

White sharks reproduce via aplacental viviparity and fecundity has been reported between 2 to 10 embryos per female (^{Fergusson, 1996}; ^{Uchida et al., 1996}). Although white shark sizes are frequently overestimated, recent examinations suggest maximum growth up to 6 m of total length (TL) (^{Castro, 2011}). Diet varies according to maturity stages switching from bony fishes and invertebrates in juveniles to marine mammals for adults (^{Kerr et al., 2006}; ^{Jaime-Rivera et al., 2014}). Recent age validation using bomb radiocarbon revealed that white shark can live up 73 years old (^{Hamady et al., 2014}). This finding will change the corresponding age at maturity previously assumed for this species at California waters (i.e., 10-12 years, ^{Cailliet et al., 1985}) and also has implication for its conservation status where currently, the white shark is placed in the “Vulnerable” category in the IUCN Red List (^{Fergusson et al., 2009}).

The distribution of the white shark in the eastern Pacific Ocean ranges from the Gulf of Alaska to the Gulf of California (GOC) and from Panama to Chile (^{Klimley & Ainley, 1996}). In the GOC, white sharks have been reported in several localities (^{Galván-Magaña et al., 2010}), with the most sightings in the community “Golfo de Santa Clara” in the upper GOC. Records of white shark sightings and captures from the southern GOC have been scarcely documented. This paper reports the first capture of a juvenile female white shark in the southeastern Gulf of California, Mexico and represents the southernmost distribution of a juvenile in Mexican waters to date.

A female juvenile of white shark was caught near the shoreline in Mazatlán (22°51.050'N, 106°17. 522'W) on the December 20th, 2013. The individual was incidentally caught by the fishermen using the long-line equipment typically employed in artisanal shark fishery (Fig. 1).

Figure 1 Position of the capture of the juvenile white shark by the artisanal fishery from Mazatlán (★) (22°51.050”N, 106°17.522”W, 2013/12/20), Barras de Piaxtla (Ο) (23°35”N, 106°49”W, 2002/04/04) by ^{Corro-Espinosa (2005)} and position of a juvenile white shark tagged by John O'Sullivan by Monterey Bay Aquarium (▲) (22°53'25′N, 109°09'28′W, 2007/04/15). 

The bait used was jumbo squid (Dosidicus gigas) and skipjack tuna (Katsuwonus pelamis). Since commerce of any product, sub-product or by-product of the white shark is prohibited by Mexican fishing (NOM-029-PESC-2006) and environmental (NOM-059-SEMARNAT-2010) laws, the specimen was inaccessible making an examination of stomach content and gonad condition impossible. We estimated a fork length (FL) of 1.6 m (based on objects relative to the shark) and TL of 1.83 cm estimated using the FL-TL relationship of ^{Mollet & Cailliet (1996)} (photo was taken with a digital camera, image was analyzed using the Image Pro Plus 7.0 software and calibrated with a known object) and total weight of 70 kg (reported by local fisherman) (Fig. 2). The jaw was obtained from the fisherman and kept to Facultad de Ciencias del Mar from Universidad Autónoma de Sinaloa at Mazatlán.

Figure 2 A female juvenile of white shark caught off the coast of Mazatlán (22°51.050'N, 106°17.522'W) on the December 20th, 2013 by artisanal fishermen. 

In Mexico, the white shark studies have been focused at Cedros, San Benito, Guadalupe, and the Revillagigedo Islands, also reported along the western coast of Baja California Peninsula, and its presence in GOC has been few documented (^{Galván-Magaña et al., 2010}; ^{Domeier, 2012}). Although spotty occurrences and governmental laws have limited the ability to gather knowledge on the biology of the white shark, satellite-based tagging technology has made important steps towards understanding patterns of movement and migration of large pelagics, including some sharks (^{Boustany et al., 2002}; ^{Weng et al., 2007a}; ^{Domeier & Nasby-Lucas 2008}; ^{Lyons et al., 2013}).

The long-distance migration of white sharks from Californian waters to Hawaii has shown that water temperature does not necessarily restrict the distribution of the species (^{Boustany et al., 2002}). A similar example of large-scale migrations of a female white shark from South Africa to Australia provides direct evidence of the capability white sharks to travel long distances that were not necessarily correlated to environmental factors (^{Bonfil et al., 2005}).

In the northeast Pacific, the connectivity between known populations of white sharks in California, Guadalupe Island, and the GOC has been poorly documented. However, recent evidence exists to reelaborate the hypothesis not in the sense if connectivity exists but instead, why there would not be connected if we consider that in Isla Guadalupe takes place the highest concentration of subadult white sharks in northwestern Mexico (^{Galván-Magaña et al., 2010}; ^{Domeier & Nasby-Lucas, 2013}; ^{Oñate-González et al., 2015}). On the west coast of Baja California Peninsula, ^{Santana-Morales et al. (2012)} reported the occurrence of white sharks in artisanal fisheries based on carcass remains. Notably, these records revealed that the incidental catch of white sharks is mostly composed of (79.8%) small juveniles (≤175 cm TL). These quantities are consistent to the proportions of juveniles reported in Californian waters (^{Lowe et al., 2012}; ^{Lyons et al., 2013}). Historic reports of white sharks in the GOC show a distribution in throughout the area, juvenile and adults have been reported in upper, central and southwestern GOC but none in southeastern (^{Galván-Magaña et al., 2010}). Only one report has been documented in southeastern GOC by ^{Corro-Espinosa (2005)} who analyzed a juvenile female of 260 cm TL caught 65 km North of Mazatlán and near to the shark reported in this study (~97 km).

Presence of juvenile individuals in GOC has been reported mostly in the upper Gulf, mainly in shallow waters during the cold season (December to May) (^{Galván-Magaña et al., 2010}; ^{Oñate-González et al., 2015}), this is contrary to found in this study at southeastern GOC in cold season, in these productivity nearshore waters where most artisanal and industrial fishery operate, making them vulnerable to fishing mortality. Another report of presence was a white shark tagged with a pop-off satellite tag and released off the coast of California by the Monterey Bay Aquarium (J. O'Sullivan, pers. comm.) showed the movement of the shark southward. The satellite tag was recovered off the coast of Cabo San Lucas (southern tip of Baja California), revealing a trajectory of the juvenile white shark towards the GOC and this behavior is probably to feeding at this zone (^{Jaime-Rivera et al., 2014}). The Gulf is an area of high productivity, but also a zone with susceptibility for capture given the high fishing activity.

For decades, the white shark has been subject to considerable attention from the public and science, given its antagonistic and mysterious reputation. Although the state of knowledge about its natural history is still limited, this has gradually increased over the past decade with interesting findings. Recent age validation using bomb radiocarbon revealed that white shark can live up 73 years old (^{Hamady et al., 2014}). Although this finding has important implications for conservation, the validation, for now, is representative for specimens from Northwest Atlantic Ocean and care must be taken to assume same longevity to other oceans where habitat conditions may have different patterns or dynamics (L. Natanson, NEFSC-NOAA, pers. comm.).

Bycatch of white sharks in different fisheries from northwest of Mexico is not frequently reported and there is little or nothing opportunity to collect data from dead specimens. Although white sharks are considered in both fishing and environmental laws, until a combination of comprehensive educational programs and more rigorous enforcement of laws takes place, captures of the white shark in Mexico will continue to be considered a trophy of low price meat and very expensive jaws in the black markets.