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Records of white shark, Carcharodon carcharias, in the Gulf of California, Mexico

Authors:
  • Facultad de Ciencias del Mar. Universidad Autonoma de Sinaloa.

Abstract and Figures

The white shark is known to inhabit the Gulf of California, but few published records exist for the most frequent localities of captures or sightings of this protected and relatively uncommon shark in Gulf waters. We have compiled and here report 38 records of white shark captures and reliable sightings for the Gulf. Records include individuals caught as by-catch by shrimp trawlers and gill-nets, and several sightings by divers or at fishing camps with corroborating photographs or sets of jaws (teeth). The main locations of occurrence were El Golfo de Santa Clara (13 records), followed by Santa Rosalía (4), and San Pedro Mártir and San Pedro Nolasco Islands (3 each). Presence of juveniles (<300 cm total length) was highest from January to May (10 records); whereas in July and October only two juveniles were recorded. Adults were more common from December to May (8 records); whereas from June to October there were fewer (5). Human induced threats and conservation of the white shark in the Mexican Pacific are briefly discussed.
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Records of white shark, Carcharodon
carcharias, in the Gulf of California, Mexico
felipe galva
n-magan
~a
1
, edgar mauricio hoyos-padilla
1
, carlos j. navarro-serment
2
and fernando ma
rquez-fari
as
3
1
Centro Interdisciplinario de Ciencias Marinas, Apartado Postal 592, CP 23000, La Paz, Baja California Sur, Me
´xico,
2
Onca Maya
A.C. Playa Copacabana #3049, Col. Primavera, CP 64830, Monterrey, Nuevo Leo
´n, Me
´xico,
3
Facultad de Ciencias del Mar,
Universidad Auto
´noma de Sinaloa, Paseo Claussen s/n, Apartado Postal 610, Mazatla
´n, Sinaloa, CP 82000, Me
´xico
The white shark is known to inhabit the Gulf of California, but few published records exist for the most frequent localities of
captures or sightings of this protected and relatively uncommon shark in Gulf waters. We have compiled and here report 38
records of white shark captures and reliable sightings for the Gulf. Records include individuals caught as by-catch by shrimp
trawlers and gill-nets, and several sightings by divers or at fishing camps with corroborating photographs or sets of jaws
(teeth). The main locations of occurrence were El Golfo de Santa Clara (13 records), followed by Santa Rosalı
´a (4), and
San Pedro Ma
´rtir and San Pedro Nolasco Islands (3 each). Presence of juveniles (,300 cm total length) was highest from
January to May (10 records); whereas in July and October only two juveniles were recorded. Adults were more common
from December to May (8 records); whereas from June to October there were fewer (5). Human induced threats and conserva-
tion of the white shark in the Mexican Pacific are briefly discussed.
Keywords: white shark, Carcharodon carcharias, by-catch, sightings, Gulf of California
Submitted 16 May 2010; accepted 6 September 2010
INTRODUCTION
The white shark, Carcharodon carcharias, is generally known
as a coastal and offshore species, usually found close to conti-
nental and insular shelves in temperate and sub-tropical seas.
However, it has also been recorded oceanically (transiting
individuals) and occurs in the equatorial tropics as well
(Klimley & Ainley, 1996). Its distribution in the eastern
Pacific ranges from the Gulf of Alaska to the Gulf of
California and the Revillagigedo Islands and from Panama
to Chile (Klimley & Ainley, 1996). Compared with other
sharks, little is known of its abundance (Compagno, 1984).
In Mexico, the white shark has been recorded at Cedros,
San Benito, Guadalupe, and the Revillagigedo Islands in the
Mexican Pacific, and is occasionally observed along the
western coast of the Baja California Peninsula (McCosker &
Lea, 1996). Heretofore, its presence in the Gulf of California
was limited to a few records (Kato, 1965; Galva
´n-Magan
˜a
et al., 1989). The aim of this study is to summarize all
records of white sharks in the Gulf of California.
MATERIALS AND METHODS
White shark captures were reported from Gulf of California
fishing camps in the States of Baja California, Baja
California Sur and Sonora, Mexico. Information on white
sharks came from three primary sources: (1) records from
local newspapers; (2) white shark sightings made by scientists
and reliable divers; and (3) shark parts or photographs exam-
ined by the authors. Whenever possible, the appropriate fish-
ermen were contacted to obtain more information about such
records. Some individuals were sexed and variously measured,
but several records lacked any reliable measurements, and
total length (TL) was estimated by examining photographs
and/or sets of jaws. To estimate TL of photographed speci-
mens, we compared the shark’s length with that of adjacent
persons or objects of known size in the photographs (Gadig
& Rosa, 1996). For calculation of TL from jaw (tooth)
measurements, we used the methodology of Shimada
(2003), measuring the height of the enamel of the largest
tooth.
RESULTS
Thirty-eight records of white shark from 17 localities in the
Gulf of California are presented here (Table 1; Figure 1).
The locality with most sightings/captures was El Golfo de
Santa Clara, Sonora, in the uppermost Gulf. In the central
Gulf, between the Baja California Peninsula and Sonora
(including several islands), a higher number of white sharks
were recorded compared to lower Gulf localities, where
records were restricted to the peninsula in the south-western
Gulf.
White shark captures occurred mainly in (now illegal)
totoaba gill-nets or shrimp trawl nets at different depths
(990 m). Also, reliable SCUBA divers sighted white sharks
at 30 40 m depths near San Pedro Ma
´rtir and San Pedro
Nolasco Islands (Figure 1).
Corresponding author:
F. Galva
´n-Magan
˜a
Email: galvan.felipe@gmail.com
1
Marine Biodiversity Records, page 1 of 6. #Marine Biological Association of the United Kingdom, 2010
doi:10.1017/S1755267210000977; Vol. 3; e111; 2010 Published online
Table 1. Chronology of records of white shark in the Gulf of California (See Figure 1).
No. Date Location TL (cm) Sex Remarks Source
1 1964 Bahı
´a Kino, Sonora 500 ? Photograph Carlos Navarro, personal
communication
2 Summer 1970 San Pedro Ma
´rtir Island ? Sighted (30 m depth) by diver M. Hoyos, personal
communication
3 1974 Bahı
´a de Guaymas, Sonora 425 ? Caught in gill-net at Rio Escondido
(in front of Islas Mellizas).
Reported weight: 1000 kg
El Imparcial28 January 2008
4 8 February 1981 Las A
´nimas Island 268 F Photographed/carcass rendered at El
Pardito Island. Caught at 40– 90 m
depth
Authors sampled
5 9 July 1981 Punta Arenas, BCS 246 M Juvenile. Jaw set preserved at
CICIMAR
Authors sampled
6 Winter 1986 El Golfo de Santa Clara,
Sonora
450 ? Caught in totoaba gill-net (12 inch
mesh); remains of two dolphins
(Tursiops truncatus) in stomach
Picture. Carlos Navarro,
personal communication
7 1987 Bahı
´a Miramar, Guaymas,
Sonora
350 ? Stranded alive Carlos Navarro, personal
communication
8 1988 El Golfo de Santa Clara,
Sonora
400 ? Caught in shrimp-trawler net. Jaw set
preserved. Teeth length: 30 mm
Carlos Navarro, personal
communication
9 1989 El Golfo de Santa Clara,
Sonora
300 ? Jaw set preserved. Teeth length:
20.6 mm
Carlos Navarro, personal
communication
10 April 1990 El Golfo de Santa Clara,
Sonora
350 ? Jaw set preserved. Teeth length:
24.8 mm
Carlos Navarro, personal
communication
11 9 April 1990 El Golfo de Santa Clara,
Sonora
200 ? Head Carlos Navarro, personal
communication
12 December 1990 El Burro, SE of El Golfo de
Santa Clara, Sonora
650 ? Caught in totoaba gill-net set at 9 m
depth. Photograph
Carlos Navarro, personal
communication
13 January 1991 El Golfo de Santa Clara,
Sonora
300 ? Caught in totoaba gill-net Carlos Navarro, personal
communication
14 1 January 1991 El Golfo de Santa Clara,
Sonora
300 ? Caught in totoaba gill-net. Jaw set
preserved
Carlos Navarro, personal
communication
15 26 February 1991 El Burro, south-east of El
Golfo de Santa Clara,
Sonora
200 ? Caught in totoaba gill-net set at 15 m
depth. Teeth length: 19.6 mm
Carlos Navarro, personal
communication
16 March 1991 El Burro, south-east of El
Golfo de Santa Clara,
Sonora
200 ? Caudal fin and dry rests Carlos Navarro, personal
communication
17 1 March 1991 El Golfo de Santa Clara,
Sonora
250 ? Caudal fin and skeleton rests Carlos Navarro, personal
communication
18 4 April 1991 El Burro, SE of El Golfo de
Santa Clara, Sonora
200 M Caught in totoaba gill-net set at 13 m
depth. Jaw set preserved. Teeth
length: 17 mm
Carlos Navarro. Personal
communication.
19 Summer 1995 San Pedro Nolasco Island 450 ? Sighted by SCUBA divers at 40 m
depth
M. Hoyos, personal
communication
20 1996 San Pedro Ma
´rtir Island 500 F Caught on long-line set from
fisherman. Photograph
Juan Pablo Gallo, personal
communication
21 October 1996 San Pedro Nolasco Island 300 ? Sighted at the surface Sighted by Carlos Navarro.
22 25 May 1997 San Pedro Nolasco Island 235 M Juvenile (semi-calcified claspers.
26 cm long). 145 kg body weight
Fernando Ma
´rquez, personal
communication
23 25 May 1997 Isla Pa
´jaros, Bahı
´ade
Guaymas, Sonora
330 ? 350 kg body weight. Photograph and
jaw
Fernando Ma
´rquez, personal
communication
24 October 1999 North of Isla Tiburo
´n ? ? Sighted swimming at the surface over
very deep water
F. Ma
´rquez, Instituto
Nacional de Pesca, personal
communication
25 October 1999 South of Isla Tiburo
´n ? ? Sighted feeding on floating whale
carcass
T. Pfister, Prescott College,
personal communication
26 2000 Santa Rosalı
´a, BCS 284 ? TL calculated from teeth using
method of Shimada (2003)
Jaw set preserved at
CICIMAR, La Paz, BCS.
27 April 2001 Boca del A
´lamo, BCS 346 M Caught in gill-net set 25 miles
offshore. Mature well-developed
claspers
Two photographs (M. Hoyos)
28 October 2003 San Bruno, BCS 450 500 ? Size estimated by authors Carlos Navarro, personal
communication
29 4 June 2004 Canal de Salsipuedes 400 ? Sighted swimming with Delphinus
capensis
Carlos Navarro, personal
communication
Continued
2felipegalva
n-magan
~aet al.
In some captured specimens, the authors did the examin-
ation of stomach contents of some adults (300 400 cm TL)
which consisted of bottlenose dolphins (Tursiops truncatus),
unidentified whale remains and California sea lions
(Zalophus californianus). A juvenile specimen examined had
an empty stomach.
No seasonal particularly notable shifts in distribution (‘pre-
ferences’) were seen in the records. Nineteen records were
from the cold season (December to May) and seven records
were from the warm season (June to November) (Table 1).
The presence of juveniles (,300 cm TL) was highest
during the cold season with ten records; whereas during the
warm season only one juvenile was recorded. Adults were
more common during the cold season with nine records;
whereas in the warm season six adults were recorded.
DISCUSSION
The white sharks reported here ranged from 170 to .500 cm
TL. Working with records worldwide Compagno (2001)
reported size at maturity for males to be between 350 and
410 cm TL, and between 400 and 500 cm for females.
Unfortunately, for most of our Gulf of California records we
lack data on gender and thus could not accurately determine
reproductive stage. However, we can infer from size-ranges
that 15 records corresponded to juveniles and 14 to adults
specimens. The remaining records belonged to unmeasured
individuals.
Presence of juveniles was mostly restricted to the upper
Gulf, mainly in the relatively shallow waters off the fishing
town of El Golfo de Santa Clara (Figure 1), and this is prob-
ably associated with feeding habits. Juveniles apparently
show a dietary preference for benthic and coastal fish
(Klimley, 1984; Tricas & McCosker, 1984), and the northern
Gulf is habitat to seasonally large schools of medium to large-
sized fish, such as the endemic species Gulf corvina
(Cynoscion othonopterus) and totoaba (Totoaba macdonaldi),
which could be consumed by juveniles.
Navarro & Arizmendi (2003) and Salomo
´n-Aguilar et al.
(2009) reported an abundance of newborns and pregnant
females of several shark species in the Gulf, suggesting that
this area could be an important nursery area. Klimley
(1985) found white shark pups in California waters that
were probably born off the coast of northern Baja California
to Santa Barbara, California, at the northern edge of the tem-
perate zone.
Considering the general absence of large white sharks in
these southern coastal areas, it is possible that more
northern-occurring gravid females move southward into this
environment to release their pups so as to optimize their sur-
vival and decrease risk of predation. No newborns or pregnant
females have been recorded in the Gulf of California, and
there is no evidence of births there. However, the presence
of small (,3 m TL) juveniles, suggests that the northern
Gulf of California may be a secondary nursery ground,
where juveniles apparently migrate from cool waters in the
Pacific on the outer side of the Baja Peninsula to warmer
waters in the Gulf (http://www.topp.org/blog/2_200_mile_
journey_juvenile_white_shark) to find locations with
abundant food for growth and protection (Bass, 1978).
Juveniles were more frequent in the northern Gulf from
January to April when sea surface temperatures were lowest
(average 158C).
Adults were recorded in the Gulf of California during
the whole year at a range of sea surface temperatures
Table 1. Continued
No. Date Location TL (cm) Sex Remarks Source
30 18 July 2004 San Pedro Ma
´rtir Island 500 ? Sighted feeding on floating whale
carcass
F. Ma
´rquez, Instituto
Nacional de Pesca, personal
communication
31 26 September 2004 Santa Marı
´a (close to
Santa Rosalı
´a), BCS
500 M Three colour photographs El Sudcaliforniano∗∗,28
September 2004
32 22 December 2004 Carmen Island 600 ? Sighted at east of island, swimming
fast to dolphin (Delphinus sp.)
group
Carlos Navarro, personal
communication
33 25 December 2004 Carmen Island 400 ? Caught in shark gill-net Carlos Navarro, personal
communication
34 2004 Santa Rosalı
´a, BCS 183 ? Length calculated from jaw teeth
using method of Shimada (2003)
Jaw set preserved at
CICIMAR, La Paz, BCS
35 2 February 2006 Bahı
´a San Luis Gonzaga,
BCS
170 ? Juvenile. Photograph J. O’Sullivan, Monterey Bay
Aquarium, Personal
communication
36 17 March 2006 El Golfo de Santa Clara,
Sonora
250 ? Photograph Lloyd Findley, J.C. Barrera,
personal communications
37 July 2007 Santa Rosalı
´a, BCS ? ? Jaw set photographed D. Aurioles, CICIMAR, La
Paz, BCS, personal
communication
38 February 2010 El Golfo de Santa Clara,
Sonora
400 ? Photograph published. Weight
902 kg, caught in shrimp gill-net.
Stomach with dolphin and sea lion
remains
Tribuna de San Luis∗∗∗,21
February 2010
,El Imparcial, a daily newspaper published in Hermosillo, Sonora; ∗∗,El Sudcaliforniano, a daily newspaper published in La Paz, BCS; ∗∗∗,Tribuna de
San Luis, a daily newspaper published in San Luis Rı
´o Colorado, Sonora; BCS, Baja California Sur.
white shark records in gulf of california 3
(15308C). According to Klimley (1985), water temperature
does not determine white shark distribution in adults. Bass
(1978) suggested that water temperature was not an impor-
tant factor for the presence of larger white sharks off eastern
South Africa, because they were recorded from February to
June when temperatures decreased, but they were absent
from September to January when similar temperatures
were recorded.
Fig. 1. Localities (numbered) and frequencies of records (size of circles) of white shark sightings and captures in the Gulf of California (also see Table 1).
4felipegalva
n-magan
~aet al.
Klimley (1985) stated that adult white sharks off south-east
Farallon Island, California, were present from August to
March, but were absent from April to July. Based on records
of sightings and captures of white sharks off Farallon Island,
this last author suggested that adult white sharks travelled
southward to waters off Baja California to breed from
March to June. The presence of adults in the Gulf of
California (this paper) could support this hypothesis, although
the majority of our records represent juvenile specimens.
The presence of adult white sharks near California sea lion
(Zalophus californianus) colonies at San Pedro Ma
´rtir and San
Pedro Nolasco Islands (Aurioles & Zavala, 1994), may indicate
that prey availability influences white shark distribution in the
Gulf of California. There are records of at least 30 marine
mammal species occurring permanently or seasonally in the
Gulf of California (26 cetaceans, four pinnipeds), making it
one of the most diverse areas worldwide for marine
mammals (Vidal et al., 1993), and several of those species
could serve as important prey for adult white sharks.
Abundant availability of food, e.g. large schools of
demersal squid, small pelagic, benthic and demersal fish in
the Gulf of California would allow the presence of white
sharks, as happens with several species of both large and
small sharks which also use the shallow waters and coastal
bays of the Gulf of California as nursery areas, including ham-
merhead sharks (Sphyrna lewini and S. zygaena), smooth
hound sharks (Mustelus henlei,M. lunulatus and M. californi-
cus), blacktip sharks (Carcharhinus limbatus), Pacific sharp-
nose sharks (Rhizoprionodon longurio), and tiger sharks
(Galeocerdo cuvier) (Navarro & Arizmendi, 2003; Ma
´rquez-
Farı
´as et al., 2006; Galvan, 2009; Salomon-Aguilar et al., 2009).
Although we have little information on how the white
shark uses the Gulf of California, records of its areas of occur-
rence probably indicate feeding areas for adults around
islands, where marine mammals (especially California sea
lion) are abundant, or areas where coastal and benthic and
demersal fish are abundant and form important prey for
juveniles.
Conservation and management implications
Although the white shark is included in the Mexican Official
regulation (NOM-ECOL-059) prohibiting its commercial
capture, enforcement mechanisms are insufficient, or they
are not well implemented. There are no specific actions to
protect this shark in Mexico, even though it continues to be
captured as by-catch in artisanal fisheries off the western
coast of Baja California and in the Gulf of California.
We hope that white shark occurrences in the Gulf of
California here reported will serve to increase enforcement
of protection regulations and aid in the conservation of this
important worldwide apex predator.
ACKNOWLEDGEMENTS
We thank Juan Pablo Gallo-Reynoso and Lloyd Findley
(Centro de Investigacio
´n en Alimentacio
´n y Desarrollo,
AC-Guaymas), Rita Benavides (OVIS Organizacio
´n Vida
Silvestre AC), Omar Vidal (World Wildlife Fund-Mexico),
Jose I. Castro (National Marine Fisheries Service), John
O’Sullivan (Monterey Bay Aquarium, California), David
Aurioles (Centro Interdisciplinario de Ciencias Marinas, La
Paz), Juan Carlos Barrera (Comisio
´n de Ecologı
´ay
Desarrollo Sustentable del Estado de Sonora) and Tad
Pfister (Prescott College, Kino Bay) for information on
white shark records. We thank the Instituto Polite
´cnico
Nacional (Comisio
´n de Operacio
´n y Fomento de
Actividades Acade
´micas, Estimulo al desempen
˜o del investi-
gador y Programa institucional de formacio
´n de investiga-
dores) for research fellowships. Thanks also to two
anonymous referees for English editing and valuable com-
ments on our manuscript.
REFERENCES
Aurioles-Gamboa D. and Zavala-Gonza
´lez A. (1994) Algunos factores
ecolo
´gicos que determinan la distribucio
´n y abundancia del lobo
marino Zalophus californianus, en el Golfo de California. Ciencias
Marinas 20, 535– 553.
Bass A.J. (1978) Problems in studies of sharks in the southwest Indian
Ocean. In Hodgson E.S. and Mathewson R.F. (eds) Sensory biology
of sharks, skates and rays. Arlington: Office of Naval Research,
Department of the Navy, pp. 545594.
Compagno L.J.V. (1984) Sharks of the world. An annotated and illustrated
catalogue of shark species known to date. Part 1. Hexanchiformes to
Lamniformes. Rome: FAO, pp. 249. [FAO Species Catalogue no. 125,
vol. 4.]
Compagno L.J.V. (2001) Sharks of the world. An annotated and
illustrated catalogue of shark species known to date. Volume 2.
Bullhead, mackerel and carpet sharks (Heterodontiformes,
Lamniformes and Orectolobiformes). FAO Species Catalogue for
Fishery Purposes 1, 1269.
Gadig O.B.F. and Rosa R.S. (1996) Occurrence of the white shark along
the Brazilian coast. In Klimley A.P. and Ainley D.G. (eds) Great white
sharks: the biology of Carcharodon carcharias. San Diego, CA:
Academic Press, pp. 347350.
Galva
´n M.F. (2009) La pesquerı
´a de tiburones en Baja California Sur. In
Urciaga G.J., Beltra
´n M.L.F. and Lluch B.D. (eds) Recursos marinos y
servicios ambientales en el desarrollo regional. La Paz, Baja California
Sur, Me
´xico: Centro de Investigaciones Biolo
´gicas del Noroestepp,
pp. 227– 244.
Galva
´n-Magan
˜a F., Nienhuis H.J. and Klimley A.P. (1989) Seasonal
abundance and feeding habits of sharks of the lower Gulf of
California, Mexico. California Fish and Game 75, 7489.
Kato S. (1965) White shark, Carcharodon carcharias, from the Gulf of
California, with a list of the sharks in Mazatlan, Mexico. Copeia
1965, 384.
Klimley A.P. (1984) The predatory behavior of the white shark. American
Scientist 82, 122– 133.
Klimley A.P. (1985) The area distribution and autoecology of the white
shark, Carcharodon carcharias, off the west coast of North America.
Memoirs of the Southern California Academy of Sciences 9, 15– 40.
Klimley A.P.and Ainley D.G. (eds) (1996) Great white sharks: the biology of
Carcharodon carcharias. San Diego, CA: Academic Press, 528 pp.
Ma
´rquez-Farı
´as J.F., Rodrı
´guez-Valencia J.A. and Cisneros-Mata M.A.
(2006) Distribucio
´n y migracio
´n de tiburones pela
´gicos en el Golfo de
California y sus zonas adyacentes. Reporte te
´cnico parcial de investiga-
cio
´n conjunta entre el Instituto Nacional de la Pesca y el Programa
Golfo de California de WWF-Me
´xico. (Agosto 2004Agosto 2006).
29 pp. Available at: http://www.wwf.org.mx/wwfmex/publicaciones.
php?tipo¼reps
white shark records in gulf of california 5
McCosker J.E. and Lea R.L. (1996) White shark attacks in the eastern
Pacific Ocean, an update and analysis. In Kimley A.P. and Ainley
D.G. (eds) Great white sharks: the biology of Carcharodon carcharias.
San Diego, CA: Academic Press, pp. 419434.
Navarro C. and Arizmendi E. (2003) Observaciones sobre los tiburones del
alto Golfo de California. I Foro de Intercambio Cientı
´fico Sobre
Tiburones y Rayas. Guaymas, Sonora: Instituto Nacional de la Pesca.
[Abstract.] Available at: http://cripson3.tripod.com/textos/c-5.htm
Salomo
´n-Aguilar C., Villavicencio-Garayzar C. and Reyes-Bonilla H.
(2009) Shark breeding grounds and seasons in the Gulf of
California: fishery management and conservation strategy. Ciencias
Marinas 35, 369– 388.
Shimada K. (2003) The relationship between the tooth size and total body
length in the white shark, Carcharodon carcharias (Lamniformes:
Lamnidae). Journal of Fossil Research 35, 28 33.
Tricas T.C. and McCosker J.E. (1984) Predatory behavior of the white
shark (Carcharodon carcharias), with notes on its biology.
Proceedings of the California Academy of Sciences 43, 221 238.
and
Vidal O., Findley L.T. and Leatherwood S. (1993) Annotated checklist of
the marine mammals of the Gulf of California. Proceedings of the San
Diego Society of Natural History 28, 16 pp.
Correspondence should be addressed to:
F. Galva
´n-Magan
˜a
Centro Interdisciplinario de Ciencias Marinas
Apartado Postal 592
CP 23000, La Paz
Baja California Sur, Me
´xico
email: galvan.felipe@gmail.com
6felipegalva
n-magan
~aet al.
... Aunque los tiburones blancos juveniles se mueven principalmente en regiones costeras, también se han registrado en la Isla Guadalupe, donde solo hacen recorridos cerca de la costa insular (Hoyos-Padilla et al. 2016). Además, se ha documentado la presencia de tiburones de esta especie, tanto juveniles como adultos, dentro del Golfo de California (Galván-Magaña et al. 2010). En el Golfo de México se han registrado tiburones blancos juveniles y adultos, aunque su presencia en esta región es rara (Compagno 2001) y se cuenta con pocos registros (Adams et al. 1994). ...
... Debido a esta razón, los registros de pesca de esta especie son escasos, o incluso nulos si se toma en cuenta los avisos y reportes de arribo para las empresas pesqueras. Sin embargo, en los pocos estudios de las capturas incidentales de Tiburón blanco en aguas mexicanas, se puede observar que la costa occidental de Baja California es un área importante de pesca incidental de esta especie (Santana-Morales et al. 2012¸Castillo-Géniz et al. 2016, así como el Golfo de California donde se tienen datos de observaciones y de captura incidental de individuos juveniles y adultos (Galván-Magaña et al. 2010). Es complicado entender cómo es el comercio nacional de esta especie, pues solo se menciona cuando existe un estudio dirigido a documentar la captura de elasmobranquios, pero no se observa registro alguno cuando se trata de documentos referentes a su comercialización en el país. ...
... También existen flotas pesqueras industriales en Puerto Peñasco y en Guaymas, Sonora, que se dedican a la captura de tiburones de talla pequeña (conocidos localmente como cazones), escama y camarón, respectivamente. En estas pesquerías también se han documentado la captura incidental de tiburones blancos (Galván-Magaña et al. 2010). Las pesquerías en donde se ha documentado con mayor frecuencia la captura de C. carcharias son las redes agalleras, las redes de deriva y los palangres (figura 12.12). ...
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La presente obra es resultado de la participación de expertos provenientes del sector gubernamental, académico y privado, con un total de 36 autores que compilaron información contenida en investigaciones científicas y material bibliográfico (tesis de posgrado, libros y artículos científicos). Sin duda, el contenido facilitará significativamente la labor de la Autoridad Científica cites de México, pues aporta elementos para analizar y emitir DENP de manera oportuna, además de apoyar a las autoridades Administrativa y de Aplicación de la Ley de México para su efectiva implementación de la cites, cuyo tratado internacional es uno de los más efectivos para la gestión de nuestro patrimonio natural, del cual dependen la subsistencia y modos de vida en el largo plazo de las comunidades pesqueras.
... Aunque los tiburones blancos juveniles se mueven principalmente en regiones costeras, también se han registrado en la Isla Guadalupe, donde solo hacen recorridos cerca de la costa insular (Hoyos-Padilla et al. 2016). Además, se ha documentado la presencia de tiburones de esta especie, tanto juveniles como adultos, dentro del Golfo de California (Galván-Magaña et al. 2010). En el Golfo de México se han registrado tiburones blancos juveniles y adultos, aunque su presencia en esta región es rara (Compagno 2001) y se cuenta con pocos registros (Adams et al. 1994). ...
... Debido a esta razón, los registros de pesca de esta especie son escasos, o incluso nulos si se toma en cuenta los avisos y reportes de arribo para las empresas pesqueras. Sin embargo, en los pocos estudios de las capturas incidentales de Tiburón blanco en aguas mexicanas, se puede observar que la costa occidental de Baja California es un área importante de pesca incidental de esta especie (Santana-Morales et al. 2012¸Castillo-Géniz et al. 2016, así como el Golfo de California donde se tienen datos de observaciones y de captura incidental de individuos juveniles y adultos (Galván-Magaña et al. 2010). Es complicado entender cómo es el comercio nacional de esta especie, pues solo se menciona cuando existe un estudio dirigido a documentar la captura de elasmobranquios, pero no se observa registro alguno cuando se trata de documentos referentes a su comercialización en el país. ...
... También existen flotas pesqueras industriales en Puerto Peñasco y en Guaymas, Sonora, que se dedican a la captura de tiburones de talla pequeña (conocidos localmente como cazones), escama y camarón, respectivamente. En estas pesquerías también se han documentado la captura incidental de tiburones blancos (Galván-Magaña et al. 2010). Las pesquerías en donde se ha documentado con mayor frecuencia la captura de C. carcharias son las redes agalleras, las redes de deriva y los palangres (figura 12.12). ...
Chapter
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El Tiburón sedoso, Carcharhinus falciformis, tiene una distribución circunglobal, se localiza tanto en el Atlántico Occidental y Pacífico Oriental. En México, C. falciformis se encuentra en el Pacífico Mexicano, incluyendo el Golfo de California, así como en el litoral del Golfo de México y Mar Caribe. Los tiburones sedosos habitan generalmente plataformas continentales e insulares, pendientes e incluso se han registrado ocasionalmente en aguas someras (18 m) hasta profundidades de 550 m. La edad máxima estimada para C. falciformis varía considerablemente para las distintas poblaciones, desde ocho a 11 años hasta más de 30 años. Los parámetros de crecimiento son también altamente variables, con longitudes asintóticas que van de 240 cm a 340 cm de LT (longitud total). El Tiburón sedoso presenta una estrategia de reproducción vivípara placentaria, con un periodo de gestación de 11 a 12 meses y una fecundidad de una a 25 crías con tallas entre 50 y 83 cm (LT). En el 2014 C. falciformis fue enlistada en el Apéndice II de la Convención sobre la Conservación de las Especies Migratorias de Animales Silvestres (CMS) y en 2017 se incluyó en el Apéndice II de la Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres (CITES). En México, la falta de información de captura y esfuerzo pesquero específico ha complicado la evaluación del estado de las poblaciones de tiburones, en donde C. falciformis no es la excepción. Por ello, es necesario hacer registros específicos de las capturas, esfuerzo pesquero, datos biológicos-pesqueros, con el fin de realizar análisis demográficos y proyecciones del efecto de la pesca en el stock e identificar áreas de importancia para su protección.
... Asimismo, en años recientes, se ha registrado un número importante de individuos pertenecientes a estos estadios tempranos de vida en regiones insulares tales como Isla Guadalupe, Isla de Cedros e Isla Natividad (Tamburin et al., 2019b;García-Rodríguez et al., en revisión;Santana-Morales et al., en prep.). Paralelamente, se ha documentado la captura incidental de individuos de todos los estadios ontogénicos en el Golfo de California, (Kato, 1965;Galván-Magaña et al., 2010;Márquez-Farías y Lara-Mendoza, 2017), incluyendo las costas de Sonora (Santana-Morales, obs. Pers.), lo que confirma su distribución en distintas partes del Pacífico mexicano. ...
... Asimismo, se han registrado Tiburones Blancos en otras áreas naturales protegidas de la Conanp como la Reserva de la Biosfera Islas del Pacífico (Tamburin et al., 2019b;García-Rodríguez et al., en revisión); Área de Protección de Flora y Fauna Islas del Golfo de California (Kato, 1965;Galván-Magaña et al., 2010;Márquez-Farías y Lara-Mendoza, 2017), y en el Parque Nacional Archipiélago de Revillagigedo (Becerril-García et al., 2020a). ...
... En México existen suficientes evidencias que indican que la captura incidental asociada a la pesca costera con redes dirigida a otras especies en la costa oeste de Baja California y en el Golfo de California, representa la mayor amenaza para el Tiburón Blanco (Galván-Magaña et al., 2010, Santana-Morales et al., 2012Oñate et al., 2017), a pesar de que la especie está protegida por la legislación mexicana. Después de la disminución de la captura incidental en aguas de California a raíz de las restricciones de redes de enmalle en las aguas estatales , la captura incidental por la pesca en México provoca que la mortalidad sea mayor a la que se presenta en California (Benson et al., 2018). ...
... Asimismo, en años recientes, se ha registrado un número importante de individuos pertenecientes a estos estadios tempranos de vida en regiones insulares tales como Isla Guadalupe, Isla de Cedros e Isla Natividad (Tamburin et al., 2019b;García-Rodríguez et al., en revisión;Santana-Morales et al., en prep.). Paralelamente, se ha documentado la captura incidental de individuos de todos los estadios ontogénicos en el Golfo de California, (Kato, 1965;Galván-Magaña et al., 2010;Márquez-Farías y Lara-Mendoza, 2017), incluyendo las costas de Sonora (Santana-Morales, obs. Pers.), lo que confirma su distribución en distintas partes del Pacífico mexicano. ...
... Asimismo, se han registrado Tiburones Blancos en otras áreas naturales protegidas de la Conanp como la Reserva de la Biosfera Islas del Pacífico (Tamburin et al., 2019b;García-Rodríguez et al., en revisión); Área de Protección de Flora y Fauna Islas del Golfo de California (Kato, 1965;Galván-Magaña et al., 2010;Márquez-Farías y Lara-Mendoza, 2017), y en el Parque Nacional Archipiélago de Revillagigedo (Becerril-García et al., 2020a). ...
... En México existen suficientes evidencias que indican que la captura incidental asociada a la pesca costera con redes dirigida a otras especies en la costa oeste de Baja California y en el Golfo de California, representa la mayor amenaza para el Tiburón Blanco (Galván-Magaña et al., 2010, Santana-Morales et al., 2012Oñate et al., 2017), a pesar de que la especie está protegida por la legislación mexicana. Después de la disminución de la captura incidental en aguas de California a raíz de las restricciones de redes de enmalle en las aguas estatales , la captura incidental por la pesca en México provoca que la mortalidad sea mayor a la que se presenta en California (Benson et al., 2018). ...
Book
El objetivo general del Programa de Acción para la Conservación de la Especie Tiburón Blanco (PACE) consiste en establecer una estrategia integral de investigación, protección y conservación del Tiburón Blanco en aguas mexicanas, que permita incrementar el conocimiento de la especie, robustecer las medidas de manejo para su aprovechamiento no extractivo sustentable y prevenir y mitigar las posibles amenazas para la especie y su hábitat.
... Satellite telemetry studies have shown Gulf entry by two adult females (Domeier & Nasby-Lucas, 2013) and a juvenile male (176 cm TL at ∼2 months before Gulf entry) (Weng et al., 2012), though there have been no observations of tagged white sharks entering the Gulf use in other extensive ENP tagging studies (Domeier & Nasby-Lucas, 2008 [n = 56], Weng et al., 2007 [n = 20], Jorgensen et al., 2010 [n = 68 satellite tags, n = 78 acoustic tags]). Catch and sighting data reveal occasional white shark presence in the Gulf, but not consistently high abundance (Galván-Magaña et al., 2010). A recent historical synthesis (Galván-Magaña et al., 2010) reported 38 sightings and incidental captures over a 47 year period (1964−2010; 0.8 observations yr −1 ), with other reports of single observations (Kato, 1965;Márquez-Farías & Lara-Mendoza, 2017). ...
... Catch and sighting data reveal occasional white shark presence in the Gulf, but not consistently high abundance (Galván-Magaña et al., 2010). A recent historical synthesis (Galván-Magaña et al., 2010) reported 38 sightings and incidental captures over a 47 year period (1964−2010; 0.8 observations yr −1 ), with other reports of single observations (Kato, 1965;Márquez-Farías & Lara-Mendoza, 2017). A synthesis of artisanal fisheries data reported capture of 38 shark species, with no mention of white sharks (Saldaña-Ruiz et al., 2017), and a thorough survey of northern Gulf elasmobranch fisheries (1998−1999) also reported no white sharks captured (Bizzarro et al., 2009). ...
... The same reports also indicate catch of a large white shark (∼600 cm) around the Guaymas region in 2012, in the eastern Gulf along mainland Mexico ( Figure 1). Adult white sharks have historically been caught around Guaymas (Galván-Magaña et al., 2010) indicating broader white shark occurrence, but less information is available for the broader Gulf. ...
Article
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Large sharks shape ecosystems across their geographic ranges and have become a top research and conservation priority. Eastern North Pacific (ENP) white shark (Carcharodon carcharias) aggregations off the United States and Mexico are well described, but their population status is currently uncertain. Population assessments of ENP white sharks are complicated by migrations across international boundaries, vulnerability at aggregation sites, and undetermined mortality levels. While protective legislation exists both in the United States and Mexico, ongoing incidental and unreported catch may undermine assessments and management. Here, access to a clandestine artisanal fishery provides evidence for white shark abundance and mortality in the Gulf of California that has been underestimated by other methods (e.g., satellite telemetry, [by]catch data). Shark size estimates based on tooth measurements suggest abundance of both juvenile and mature sharks in the region, and updated population models indicate the potential for substantial impacts of this fishery on ENP population viability. The data here, fisher-provided information, and anecdotal evidence suggest potentially high abundance at two specific regions, making directed future research efforts feasible in the Gulf. These data demonstrate that cryptic life histories and geopolitical boundaries can still limit fundamental understanding of megafauna distribution, necessitating international cooperation for both research and management .
... The GC is a highly productive ecosystem that can provide White Sharks with abundant demersal and pelagic prey throughout ontogeny (Lluch-Cota et al., 2007), and possibly support a local White Shark population. However, some of their prey are targeted by local artisanal and industrial fisheries, which explains by-catch of White Sharks by local fisheries inside the GC (Galvań-Magaña et al., 2010;Madigan et al., 2021;Malpica-Cruz et al., 2021). Further, thirteen California sea lion (Zalophus californianus) colonies are found in the GC mainly in the central and northern reaches which might serve as an important food source for adult White Sharks (Masper et al., 2019;Pelayo-Gonzaĺez et al., 2021). ...
Article
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The conservation and management of highly migratory sharks relies on understanding age-related movements and nursery habitat utilization. We reconstructed the habitat use and migratory history of young White Sharks ( Carcharodon carcharias ), a highly protected species, by utilizing natural chemical tracers (element:Ca ratios and stable isotope analysis, SIA) in vertebral cartilage growth bands. Two nursery areas in the northeastern Pacific are known, but migration patterns of immature White Sharks within the Gulf of California (GC) and natal philopatry are poorly understood. Vertebrae from coastal Mexican artisanal fisheries off central Baja California in the Pacific (12 neonates and juveniles; 139-280 cm total length) and the GC (3 subadults; 289-355 cm TL) were analyzed to characterize (1) trophic histories from collagen δ ¹³ C and δ ¹⁵ N values, and (2) in utero patterns and post-birth environmental histories from element:Ca time-series. Mean δ ¹⁵ N values from vertebral edges of GC sharks, representing the most recent feeding, was +5‰ higher than in the Pacific, reflecting the intense denitrification that permeates the regional food web and supporting SIA as tracers of migration between regions. A subadult from the GC likely resided within the system throughout its life, and two subadults migrated into the GC. Most neonate and juvenile sharks caught in the Pacific had SIA that did not overlap with those of the GC, but a single subadult likely migrated to the GC. Element:Ca ratios displayed ontogenetic trends, with Li:Ca, Zn:Ca, and Ba:Ca significantly higher before the birth mark in sharks captured in the GC. Edge values were significantly higher in Zn:Ca and Ba:Ca in the GC compared to the Pacific, suggesting elemental ratios may serve as tracers of migration between regions. Subadult sharks collected from GC displayed elevated maternal Zn:Ca and Ba:Ca, suggesting mothers may have resided in the GC for an extensive period pre-birth. Some White Sharks may reside within the GC from birth until at least the subadult stage (ca. 3 m TL), and there may be an unidentified nursery. Chemical tracers, coupled with genomic and tagging studies, should improve understanding of the importance of the GC to White Shark populations in the northeast Pacific.
... Moreover, the warm season was characterized by a high abundance of M. munkiana individuals compared to the other species, illustrated by its relatively low evenness value (J′ = 0.74). Low water temperature combined with high productivity during the cold season in the ESI may allow the incursion of species with temperate affinities or deep water preferences, as well as solitary or schooling behavior (Galván-Magaña et al. 2010;Jiménez-López et al. 2019;Burgos-Vázquez et al. 2019b;Whitehead et al. 2019Whitehead et al. , 2020 influencing diversity estimates. Finally, during the warm season, the abundance of the tropical batoid species decreases near the ESI, leaving M. munkiana as the dominant species with high abundance (Palacios et al. 2021). ...
Article
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The Espiritu Santo Island (ESI) has the highest elasmobranch richness among the Gulf of California islands, exemplifying its importance for conservation. In the present study, we assessed the temporal variation of the batoid assemblages captured in the southern ESI. Using the monthly artisanal fishing fleet catch data between 2013 and 2015, we applied three methods to evaluate changes in diversity: descriptive (i.e., richness, dominance, evenness, and Shannon–Wiener index), taxonomic diversity, and functional diversity. Four orders, ten families, ten genera, and 15 species were identified. Mobula munkiana, Hypanus dipterurus, Narcine entemedor, and Rhinoptera steindachneri were the most numerically abundant (dominant) during the study period. The Biological Values Index of these species indicated temporary changes mainly attributable to sea surface temperature. Diversity and average taxonomic distinctiveness values were high, indicating stability in the batoids assemblage assessed. Further, we identified nine functional groups classified mainly into two life history types, benthic and pelagic. The former group was characterized as having small- to medium-sized species and circular and oval body shape with preferences to remain buried or on sea bottom. The second group was formed by large–body size species and rhomboid body shape with high motility in the water column and with migrations. The ESI community of batoids has a stable taxonomic structure over time, whose functional groups have adapted to the ESI environmental conditions and available resources. This study confirms and highlights the importance of ESI as a critical site for these batoid species within the Gulf of California and thus their conservation.
... La Isla San Pedro Nolasco, presentó el 6% (n = 29) de concentración de partículas, siendo así el sitio con la menor concentración encontrada. Esta isla se encuentra actualmente protegida por el Gobierno Federal por poseer características biológicas y topográficas sobresalientes, y hoy en día ya hay varios reportes de fauna y flora silvestre en este sitio y de sus aguas aledañas (Mahrt, 1979;Smith, 1985;Wilder et al., 2008;Galván-Magaña et al., 2010;Felger et al., 2011;Gallo-Reynoso et al., 2012). Por otro lado, Niño-Torres et al. (2009) reportaron la presencia de contaminantes organoclorados en la grasa de los lobos marinos de esta isla, los cuales se sabe que pueden afectar negativamente el sistema endócrino y provocar inmunosupresión en mamíferos marinos (Kannan et al., 2000). ...
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Microplastics (MPs, < 5 mm) are highly bioavailable to a great number of taxa in different trophic levels within the marine ecosystem. Despite the minimum information generated relating this subject to the Gulf of California, the analysis on the ingestion of these microparticles from top predators as the pinnipeds on Mexico is quite unexplored. For this reason, the determination of ingestion of particles of potentially MP origin (P-MPs) by the California sea lion (Zalophus californianus) will help the assessment of the exposition level to this kind of pollutant and mark them as an indicator species on the Gulf of California. To this, we collected scats from five rookeries of the Gulf of California and the coast at Cabo Haro, Guaymas, during the breeding season (July – August 2018) and the resting season (January 2020), respectively. Samples were passed through a set of sieves (1000, 500, and 212 m). Organic matter was eliminated by a process of alkaline digestion (KOH 30%), easing P-MP visual detection. Subsequently, P-MPs obtained from scat samples were visualized using a stereoscopic microscope (Olympus SZX7, 70X) equipped with a camera (Olympus LC30). We report a mean concentration of 0.40 ± 0.61 P-MPs g-1 from the scats analyzed (n = 48). It was acknowledged that there was enough evidence to support concentration differences between P-MPs from sea lion scats analyzed in this study (non-parametric Kruskal-Wallis test; H (5) = 12.40, p = 0.030). Particles founded were mainly fibers (91%) and fragments (9%). Microparticles of blue color were more abundant (53%), followed up by black (23%) and gray color (8%). Particle size distribution predominates between three ranks in similar proportions, from 250 to 500 μm, 1000 to 5000 μm, and 500 to 1000 μm (27, 26, and 25%, respectively). Even though we didn’t examine the ingestion pathway of P-MPs in sea lions, past studies suggest the approach of a trophic transfer of particles to top predators, as well as incidental ingestion while foraging. The presence of P-MPs documented here suggests the need for in-depth research studies in the correlation between these potential pollutants and the California sea lion populations in the Gulf of California.
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This chapter synthesizes information on national and international regulations in force (as of July 2018) for fisheries management, conservation, and sustainable use of shark and batoid biodiversity in the Mexico. The document is a comprehensive review of relevant published information complemented with information derived from specific interviews conducted by the author to a large number of actors from all sectors (industrial fishing, artisanal fishing, sport fishing, government, NGOs, and academia) between October and December 2014. The focus of the interviews was on the effectiveness of existing regulations towards guaranteeing the conservation of shark and batoid species. The overall analysis indicates that there is a wide range of fisheries management and conservation instruments both nationally and internationally, which are generally a good starting point to ensure the conservation and sustainable use of sharks and batoids in the country, but this is not enough, since there were important gaps observed especially in fisheries management. Additionally, an analysis of 40 Protected Natural Areas (PNA) in place in Mexico as of 2014 and which have or could have species of elasmobranchs inside them (Bonfil 2014) indicates that 10 of them do not have Management Programs, and that 22 out of 30 existing management programs for PNAs do not contain specific measures for the conservation of elasmobranchs or do not list them as existing in the PNA. The main recommendations of the analisis are: a) to reinforce and expand the programs and mechanisms of inspection, surveillance, monitoring and follow-up of all regulations for the fisheries and conservation sectors; b) to prepare as soon as possible Management Programs for all PNAs where sharks and rays are found, and modify the existing ones so that they all explicitly include the species of sharks and rays that occur in each PNA and especially, to include specific measures for the conservation of elasmobranchs in them; c) as an integral part of a strategy for change, it is recommended to implement permanent programs of environmental education focused particularly onto the actors of the fishing sector (including fishermen, processors, intermediaries, wholesalers and retailers, exporters and consumers), who are the ones who interact daily with sharks and batoids, and by this means solve the great gap in environmental awareness that exists, and d) to reassess the conservation status of manta and devil rays as well as sawfishes, with the criteria of including or updating them in NOM-059-SEMARNAT-2010.
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There are reliable records from the Gulf of California for 30 species of marine mammals representing eight families: the Phocoenidae (one species), Delphinidae (12), Ziphiidae (three), Physeteridae (three), Eschrichtiidae (one), Balaenopteridae (six), Otariidae (two), and Phocidae (two). -from Authors
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El libro es una compilacion de reportes de investigacion sobre la importancia que revisten los Recursos Marinos y los servicios ecosistemicos en el desarrollo regional
Article
Sharks show high biological fragility and, given the intense fishing regimes to which they are exposed in the Gulf of California, it is necessary to establish a conservation and management strategy providing for the protection of their nursery areas. We reviewed the literature concerning shark reproductive biology to determine priority management areas in the Gulf of California by complementarity analysis and different selection criteria. Four levels of management and conservation priority were determined for six quadrants: level 1 corresponded to the area off Mazatlán (Sinaloa) and the area of El Sargento, La Ventana, and Punta Arenas (Baja California Sur); level 2 to the areas of Teacapán (Sinaloa) and Seri (Sonora); level 3 to the areas of San Francisquito-El Barril (Baja California) and Kino Bay (Sonora); and level 4 to the area of La Manga (Sonora). Analysis of space-time variables in a geographic information system indicated that 71% of the commercially important shark species concentrate in coastal zones, mainly in bays, coastal lagoons, estuaries, and wetlands (central and southern Gulf of California) during spring and summer (May-August), except for Prionace glauca, Isurus oxyrinchus, Alopias pelagicus, and Squatina californica that reproduce in winter and spring. The protection of recruitment areas (critical habitats) during peak breeding periods should be an essential part of any resource management plan.
Chapter
We report on 20 confirmed and five purported but unreliable incidents of unpro-voked attacks by white sharks on humans in California and Oregon between 1993 and 2003. All attacks involved white sharks (Carcharodon carcharias). The discussion , map, and tables from McCosker and Lea's (1996) report are updated. The majority of attacks occurred at or near the surface, near shore, and often in the vicinity of pinniped colonies and/or river mouths and harbors. Attacks have now occurred during all months, and on surfers, breathhold and scuba divers, swimmers, hookah divers, kayakers, and, for the first time, on bodyboarders, a windsurfer, and a scuba diver using an electric propulsion device. Typical attack scenarios suggest that an adult C. carcharias mistakes its victim for a pinniped, its normal prey. Shark attacks were fewer during the extreme 1997–1998 ENSO (El Niño/Southern Oscillation) oceanographic warming event. The defensive activity of humans after being attacked and its effect are discussed. We also comment on recent legislation concerning white shark protection and disallowing the attraction of white sharks by chumming. In 1996, we (McCosker and Lea, 1996) reviewed the history, human activity, and shark activity involved with unprovoked attacks by white sharks (Carcharodon carcharias) upon humans in the eastern North Pacific Ocean (ENP). The last attack that we reported upon was that involving Rosemary Johnson on 10 October 1993. We begin this study with an attack that occurred so late in 1993 that we were unable to include it in our earlier paper. In the subsequent decade 20 unprovoked attacks upon humans by white sharks have occurred in the ENP. We herein report upon those attacks and update our analysis and conclusions. The following is a brief review of literature concerning attacks by white sharks in the ENP.
Article
Carcharodon carcharias was studied at Dangerous Reef, South Australia. A single bit action is composed of a uniform sequence of jaw and head movements. Various approach behaviors to baits were documented. Small sharks (<3 m) feed primarily on fish prey, while larger sharks feed on marine mammals, especially pinnipeds. Telemetric studies of white shark thermal biology show that they are warm-bodied, c4-5oC above ambient water temperature. -from Sport Fishery Abstracts