Arnbom, Tom

Papastavrou, Vassili

English

Aquatic Commons

Noticias de Galápagos, No. 46, May 1988
En octubre de 1987, la experiencia de campo de
Fausto fue llamado a cumplir el importante papel de
asistir a otros cinco guardaparques en un intenso censo
de tortugas en la Isla Pinzón. El censo fue todo un
éxito--fueron encontrados 45 nidos de tortugas--y
todos los participantes estuvieron de acuerdo que fue
Don Fausto quien reconoció las mejores áreas de
anidamiento, quien encontró el mayor número de nidos,
y quien aseguró el éxito del viaje.
Fausto es también conocido y admirado como un
escultor en madera. Sus tallados de madera de
tortugas tipo montura y tipo cúpula son tan
características que son reconocidas a miles de millas
de Galápagos. A pedidos especiales Fausto hace otros
animales desde pingüinos a iguanas de tierra, pero sus
tortugas son particularmente apreciados tanto por los
residentes de Galápagos como por los visitantes. Como
persona que ha vivido cerca de las tortugas desde su
niñez, y como guardaparque que ha trabajado con ellos
en el campo y en cautiverio, Fausto es único en
reproducir tortugas de un pedazo de madera a una
pieza de arte.
LUIS RAMOS VELOZ
Jefe Proveedor, Estación Científica
Charles Darwin
Luis Ramos (con respecto y cariño conocido como
Don Ramos), ha trabajado para la Estación Científica
Charles Darwin desde noviembre de 1971. Por muchos
años ha servido como el responsable principal en la
compra de alimentos, materiales, equipos, y cualquier
cosa necesaria del abastacimiento local y recibiendo la
carga procedente del continente.
En tiempos pasados, fue Don Ramos quien con su
indispensable panga proveyó a los científicos a los
barcos en el puerto con destino a otras islas, con sus
materiales, y fue el quien recogió a los científicos de
retorno de sus actividades. Don Ramos realizó
incontables viajes en panga a través del angosto canal
desde el pueblo cruzando Bahía Academy a la Estación
con materiales llegados del continente en el barco de
abastecimientos. Pero, a medida que los caminos
mejoraron y la Estación creció Don Ramos comenzó a
utilizar los vehículos de la Estación para completar sus
viajes para conseguir las provisiones y repartirlas.
Para Don Ramos no importa lo ocupado que se
encontrase, siempre encuentra tiempo para llevar a
álguien que necesita ir al pueblo o para aconsejar sobre
lugares para hacer compras. Todos, desde los
empleados a los visitantes, se han beneficiado de la
habilidad de Don Ramos de encontrar cosas necesarias
de escacez en poco tiempo, comprarlas al precio más
rasonable, y de asegurar crédito cuando el dinero no
fue disponible.
La ingenuidad de Don Ramos también le serve en
coser, para el un hobby útil. Cuando cierres, telas, y
13
la necesidad existe, el puede fabricar cualquier cosa
desde mochilas a carpas. Don Ramos tiene la habilidad
de copiar la calidad de equipos profesionales e
incorporarles modificaciones especiales útiles para la
situación de Galápagos. "Hecho por Ramos" no es
marca de un presitigioso diseño, pero para la gente de
Galápagos, es un lujo local que es disfrutado por todos
quienes necesitan reparar o remplazar equipos
esenciales de campo, fabricar títeres para programas
de educación ambiental, remplazar las cubiertas de
asiento de los vehículos, o hacer los interminables
arreglos para aseguarar el bienestar de todos en la
isla.
(Traducción por Aida Luz Aquino.)
FISH IN ASSOCIATION WITH WHALE
SHARKS RHINIODONTYPUS NEAR THE
GALAPAGOS ISLANDS
By: Tom Arnbom and Vassili Papastavrou
The whale shark (Rhiniodon typus) is the largest
shark and, in fact, is the largest fish. It reaches
lengths in excess of 12 m (Castro 1983). Virtually
nothing is known about its life history (Wolfson 1983).
Four observations of whale sharks have been recorded
in the Galápagos Islands (Gudger 1927, 1933;
Kasteleyn 1986; Wolfson 1986).
While tracking sperm whales (Physeter
macrocephalus) off the Galápagos Islands, 91000'W,
O1000'S, aboard a 10m sloop, we sighted whale
sharks on four separate occasions between 23
February and 20 April 1985 (Table 1). The
observations were in an area which is seldom visited
(Fig. 1). Little fishing if any is carried out in the area,
and no tourist boats pass this way. Tour boats
normally cruise along the coastlines. On three
occasions, we observed other species of fish in clase
proximity to whale sharks. The encounters allowed us
to make underwater observations and to take
photographs.
The whale sharks were estimated to be between
10 to 12 m long by comparing their sizes to the length
01 the research vessel. None of the whale sharks were
moving in any particular direction and their speeds
were less than 3 km/hour. One whale shark circled
around the stationary boat and approached it within
0.5 m several times.
The first observation was on 7 March and the
other three were on 13 April. The distance and time
between the second and third observations suggest
that they were two different individuals. The lourth
observation was of an individual with a noticeably deep
cut in the trailing edge of the dorsal fin and therefore
was considered to be a different individual from the
second and third observations.
14
Whale sharks appear to prefer areas where t,he
surface water temperatures are between 21 to 25 C
with cold water of 170 C or less upwelling into it
(Compagno 1984). The four observations south of
Isabela Island (Fig. 1) were in an area known for its
upwelling and noted for high primary productivity
(Feldman et al. 1984). The recorded w8ter surface
temperatures were between 23.5 and 26.5 C.
The remoras (Escheneidae sp.) observed with
whale sharks off the Galápagos were positioned on the
dorsal side of the head, underside of the jaw, and close
to the pectoral fins and the gill slits. Remoras are
hitchhiking fish that attach themselves to all manner of
hosts, e.g., sharks, rays, turtles, and whales (Tinker
1978). They feed upon various animals in the
plankton, scraps of large food items that fall from the
mouth of their host, and potentially on external
parasites and feces (Tinker 1978). Numerous
unidentified small teleosts (Iengths < 0.2 m) were
present around the mouth and gill slits of one of the
whale sharks. Off the Galápagos, one whale shark was
surrounded by a school of yellow-finned tuna
(Neothunnus macropterus) with individuals
approximately 0.75 m in length. Springer (1957)
noted that whale sharks were feeding on small fish in
the middle of schools of black-finned tuna (Thunnus
atlanticus).Although the whale shark and the tuna
species may compete for the same prey, their
association may also be beneficial for both species.
Foraging tuna which "herd" prey species into denser
schools would benefit a whale shark which was feeding
on the same prey. The prey species may be more
vulnerable to tuna when the whale shark feeds and
creates confusion among the prey species. However,
no feeding behavior of whale sharks was observed off
the Galápagos.
Two species of sharks, a tiger shark (Galeocerdo
cuvieri) and a hammerhead shark (Sphyrnidae sp.),
were observed within 10m of the whale shark. The
smaller sharks recorded together with the whale shark
may have been attracted to the concentrations of
organisms exploited by whale sharks or may just have
been casual visitors. Normally, whale sharks feed on
food much too small to be attractive to other large
sharks. Sharks (other than whale sharks) have been
reported as following sperm whales (Gambell 1970)
which are of a similar size to a whale shark. Many
fish of the open ocean seek protection in the vicinity of
larger fish (Eibl-Eibesfeldt 1970).
While the whale shark swims at a relatively slow
speed and often at the surface, it would be worth
pursuing a behavioral study of the whale shark and its
relationships to other species of fish. The present
observations and earlier reports of sightings west of
the Galápagos Islands suggest that this area may be
suitable for such studies. We suggest that
Noticias de Galápagos, No. 46, May 1988
photographic identification of natural markings, such
as spots on the whole body and the shape of the dorsal
and caudal fin, could be used for individual
identification of whale sharks. The techniques
proposed are discussed by Arnbom (1987) with
reference to sperm whales.
ACKNOWLEDGMENTS
We thank M. Brooks, L. Weilgart, and Dr. H.
Whitehead for their parts in the research at sea, and
the Charles Darwin Research Station, INOCAR, and the
Galápagos National Park Service for assistance. We
also thank Dr. J. Brown, M. Brooks, and T. Harold for
constructive comments and suggestions. The field
research was funded by F.C.P. Whitehead, D. Plage, the
Green Island Foundation, the Connecticut Cetacean
Society, the O. Engkvist Foundation, and the Center for
Studies of Whales and Dolphins. Analysis was
supported by the O. Engkvist Foundation, the Memorial
University of Newfoundland, and the Swedish-
American Foundation.
LlTERATURE CITED
Arnbom, T. 1987. Individual identification of sperm
whales. Report of the International Whaling
Commission 37:201-204.
Castro, J. 1983. The sharks of North American
waters. Texas University Press, College
Station. 180 pp.
Compagno, L.J.V. 1984. Sharks of the world. FAO
Fisheries Synopsis No. 125/4, Part 1. 249
pp.
Eibl-Eibesfeldt, 1. 1970. Ethology and the biology of
behavior. Holt, Rinehart and Winston, Inc.,
New York. 530 pp.
Feldman, G., D. Clark, and D. Halpern. 1984. Satellite
color observation of phytoplankton distribution
in the eastern equatorial Pacific during the
1982-1983 El Nino. Science 226:1069-1071.
Gambell, R. 1970. Sperm whales off Durban.
Discovery Report 35: 199-358.
Gudger, E.W. 1927. The whale shark, Rhiniodon
typus,at the Galápagos Islands - A new faunal
record. Science 65:545.
Gudger, E.W.1933. A second whale shark, Rhineodon
typus, at the Galápagos Islands. Nature
132 :569.
Kasteleyn, H. 1986. A very special dive in Galápagos
waters. Noticias de Galápagos 43:12.
Springer, S. 1957. Some observations on the
behavior of schools of fishes in the Gulf of
Mexico and adjacent waters. Ecology 38:166-
171.
Table 1. Summary of the four whale shark observations off the Galápagos Islands, 1985. Surface water
temperatures are extrapolated from measurements made at 3 hour intervals (0600, 0900, 1200, etc.).
Observation Surface Water Depth
Number Date Time Latitude Longitude Temperature (°C) (m) Other Species
1 7 March 0655 1°21 'S 91°12'W 23.5 3,000 Neothunnus macropterus
2 13 April 1010 1008'S 91°12'W 26.0 2,000 Galeocerdo cuvieri
3 13 April 1140 P10'S 91°11'W 26.5 2,000 Sphyrnidae sp.
Escheneidae sp.
Other small teleosts
4 13 April 1350 1°11 'S 91°11'W 26.5 2,000
Noticias de Galápagos, No. 46, May 1988
Tinker, S. W. 1978. Fishes of HawaiL Hawaiian
Service Ine., Honolulu. 532 pp.
Wolfson, F.H. 1983. Records of seven juveniles of the
whale shark, Rhiniodon typus. Fisheries
Biology 22:647-655.
Wolfson, F.H. 1986. Occurrences of the whale shark,
Rhiniodon typus Smith. Pp. 208-226 In R.
Uyeno, R. Arai, T. Taniuchi, and K. Matsuura
(eds.) Indo-Pacific fish biology: Proceedings of
the Second International Conference on Indo-
Pacific fishes. Ichthyological Society of
Japan, Tokyo.
15
Tom Arnbom, Department of Psychology,
Memorial Unlverslty, Sto John's,
Newfoundland, Canada A 1B 3X9. Present
Address: Department of Zoology, 5tockholm
Unlverslty, 5-106 91 5tockholm, 5weden.
Vassl" Papastavrou, Department of Zoology,
Brlstol Unlverslty, Brlstol, Unlted Klngdom.
91'W
(.f~)
1'5
[J
91'W
90'W
o 50
~llOMETRE
J
,,,,-...
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:0
', .
1#'
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1'5
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Figure 1. Isabela Island and surrounding waters where whale sharks were sighted. Numbers 1-4 indicate areas of
sightings. A dashed line indicates the 1,000 m depth contour. Isla Isabela y el mar alrededor donde se vieron los
tiburones ballena. Los números indican los sitios. La linea rayada representa la curva de nivel de 1,000 m
profundidad.


Fish in association with Whale Sharks Rhiniodon typus near the Galápagos Islands

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Fish in association with Whale Sharks Rhiniodon typus near the Galápagos Islands

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