[MARMAM] Abstracts: Aquatic Mammals, 31(4), 2005

Dagmar Fertl dfertl at geo-marine.com
Wed Jan 25 09:27:02 PST 2006

Dear Marmam and ECS-Mailbase subscribers,

Apologies to those of you on both lists for cross-posts that you will
receive. The following is posted as a courtesy to the European Association
for Aquatic Mammals (EAAM) and the journal editor, Dr. Jeanette Thomas.
These are the contents and abstracts for the latest issue of _Aquatic
Mammals_, the publication of the EAAM. Information on the society,
membership, journal subscriptions, and author guidelines may be found at the
EAAM website: http://www.eaam.org/. Detailed author guidelines may also be
found in this latest issue of _Aquatic Mammals_ or obtained by contacting:

Dr. Jeanette Thomas
Department of Biological Sciences
Western Illinois University-Quad Cities
3561 60th Street, Moline, Illinois 61265, USA
J-Thomas at wiu.edu; tel: 309-762-9481, ext 311; FAX: 309-762-6989

I have provided the address of the author to whom reprint inquiries should
be directed. No email addresses were provided with any of these articles, so
please do not ask the Marmam editors or me, for this information.

Thank you for your continued interest in the journal, the EAAM, and these


Dagmar Fertl
Marine Mammal Biologist
Geo-Marine, Inc.
550 East 15th Street
Plano, Texas 75074 USA
FAX 972-543-4130
dfertl at geo-marine.com
Mass, A.M., and A. Ya Supin. 2005. Ganglion cell topography and retinal
resolution of the Steller sea lion (_Eumetopias jubatus_). _Aquatic Mammals_

Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences,
33 Leninsky Prospect, 119701 Moscow, Russia

The total number, soma size, topographic distribution, and density of
ganglion cells were studied in retinal wholemounts of the Steller sea lion
(_Eumetopias jubatus_). Ganglion cell soma size varied from 6 to 37 μm, and
the majority of cells were of a size from 10 to 25 μm. A distinct group
were large ganglion cells of more than 25 to 37 μm, which were similar to
the α-cells known in terrestrial mammals. The number of α-like cells
constituted 8% of the total ganglion cell population. The topographic
distribution of ganglion cells showed a definite area of high cell density
similar to the area centralis of terrestrial carnivores. This area was
located in the temporal retinal quadrant, 8 to 9 mm from the optic disk. In
this area, the peak cell densities in six wholemounts ranged from 1,512 to
2,520 (mean 1,904) cells/mm^2. With a posterior nodal distance of 19 mm
(underwater), these densities corresponded to 166 to 277 (mean 209)
cells/deg^2. This predicts a mean retinal resolution of 4.15' of minimum
visibility (7.2 cycle/deg) in water and 5.5' (5.5 cycle/deg) in air.
Topographic distribution of α-like cells was qualitatively similar to that
of the total ganglion cell population, but the density of α-like cells
reached only 45 to 72 (mean 59) cells/mm^2.
K. Danil*, D. Maldini, and K. Marten. 2005. Patterns of use of Maku'a Beach,
O'ahu, Hawai'i, by spinner dolphins (_Stenella longirostris_) and potential
effects of swimmers on their behavior. _Aquatic Mammals_ 31(4),403-412.

*current address: NOAA Fisheries, Southwest Fisheries Science Center, 8604
La Jolla Shores Drive, La Jolla, CA 92037 USA

Spinner dolphins (_Stenella longirostris_) use Maku'a Beach, a small bight
along the Wa'i'ana'e coast of O'ahu, as a rest site. Behavior and use
patterns of Maku'a Beach by spinner dolphins and swimmers were studied in
July and August of 1995 to provide baseline data on the dolphin population
and to assess potential impacts of swimmers on the dolphins' resting
behavior. Dolphins were observed on 52 out of 53 days, and they entered the
area between 0545 and 0845 h. Their departure time varied widely. Average
school size was 67 ± 0.6 SE and decreased with time of day. The most common
aerial behaviors were slaps, leaps, and spins, respectively, with a peak in
aerial behavior in late afternoon associated with schools moving offshore.
The number of swimmers in the study area was highest on weekend mornings (x
= 12 ± 0.6 SE), with a maximum of 63 people in the water at the same time.
Rest appeared delayed and compressed in this population of dolphins as
compared to other studies and may be a response to the presence of swimmers
in the morning. The results suggest a potential adverse impact of swimmers
on the dolphins' resting patterns, with earlier departure times and shorter
periods of dive behavior indicative of rest.
Durden, W.N. 2005. The harmful effects of inadvertently conditioning a wild
bottlenose dolphin (_Tursiops truncatus_) to interact with fishing vessels
in the Indian River Lagoon, Florida, USA. _Aquatic Mammals_ 31(4),413-419.

Hubbs-SeaWorld Research Institute, 6295 Sea Harbor Drive, Orlando, FL
32821-8043, USA

Numerous accounts of social bottlenose dolphins (_Tursiops truncatus_)
seeking human interactions have been documented. While there are several
cases of dolphins seeking human interactions with no apparent benefit,
dolphins may also be enticed to interact with humans through gradual
habituation, usually involving a food source. Marine mammals frequently feed
in association with commercial fisheries. Dolphins residing in the Indian
River Lagoon (IRL), Florida, USA, may become conditioned to approaching
commercial blue crab boats since the fishery regularly discards old bait
fish at each trap. This routine may inadvertently acclimatize wild
bottlenose dolphins to approach fishing vessels to feed on this supplemental
food source. From 1998 to 2001, an adult bottlenose dolphin residing in the
IRL estuary system regularly associated with commercial blue crab fishing
boats. Focal observations revealed that the animal has become conditioned to
approaching commercial crab boats (n = 110 min, n = 6 observations),
spending all of its observed time feeding on discarded bait fish, following
crab boats, or begging. The dolphin is readily resighted and well-known by
fishers due to its tendency to closely approach and beg at fishing boats.
The habituated dolphin is site-specific, with all observations and sightings
(including fisher reports) occurring within a small 12.88 km area. This
unintentional food provision and habituation of wild IRL dolphins to local
fisheries may negatively impact the population. On 26 May 2001, this
habituated dolphin approached a commercial vessel with a recreational
fishing lure lodged in its mouth. Numerous reports from recreational fishers
indicate that IRL dolphins also forage in association with recreational
fisheries. Feeding and close interactions between wild dolphins and humans
can lead to both animal and human injuries and fatalities. This paper
documents the habituation of an IRL bottlenose dolphin to fishing vessels
and reports the potentially harmful consequences of these interactions.

Lima, R.P.*, C.M.C. Alvite, J.E. Vergara-Parente, D.F. Castro, E.
Paszkiewicz, and M. Gonzalez. 2005. Reproductive behavior in a
captive-released manatee (_Trichechus manatus manatus_) along the
northeastern coast of Brazil and the life history of her first calf born in
the wild. _Aquatic Mammals_ 31(4),420-426.

*Centro Mamiferos Aquaticos/IBAMA, Estrada de Forte Orange, s/n, Caixa
Postal o1, Ilha de Itamaraca/PE, Brazil CEP: 53,990-000

The West Indian manatee (_Trichechus manatus_) is an exclusively herbivorous
aquatic mammal. Recently, the stranding of live-orphaned calves has been the
main threat to the species in northeastern Brazil. Since 1989, the Brazilian
Manatee Project (PPB) has recovered 52 calf carcasses, of which 44 were
alive. In 1994, "Lua" and "Astro" were the first manatees released from
captivity in Brazil, and they have been tracked using radio telemetry
methods. During daily tracking bouts, Lua's behavior and movement patterns
were recorded, including reproductive behavior. On 17 December 2003, while
she was in the Maracaípe Estuary, Lua gave birth to her first calf.
Beginning on 18 December 2003, the mother/calf pair began repeated, tidally
determined moves from the estuary used during high tides to the sandstone
reefs used during low tides. Four days after the birth, an increase in
motorized boat traffic in Maracaípe Estuary was observed. On 22 December,
Lua and her calf moved to Serrambi Beach and remained outside the estuary in
the reef area. On 25 December, the ninth day after the birth, Lua was
sighted alone. On 26 December, the calf was found dead at Serrambi Beach.
The place of birth supports the hypothesis that estuaries are birthing areas
for manatees. The fact that Lua established her main fidelity site and gave
birth in an area where manatees had previously been extirpated indicates a
potential for reestablishing the species in its historical range via the
rescue, rehabilitation, and reintroduction program developed by PPB. The
calf's death confirms the fragility of the species' conservation. The last
44 live-orphaned calves seem to have been caused by habitat destruction
and/or human disturbances within their habitat. The lack of effective
coastal management programs, despite being mandated within the federal
Environmental Protection Areas established in the region, are factors that
severely impair conservation of the Antillean manatee in Brazil.
Wilke, M.*, M. Bossley, and W. Doak. 2005. Managing human interactions with
solitary dolphins. _Aquatic Mammals_ 31(4),427-433.

*Centre d'Etudes Hydrobiologiques, 108 Avenue du Puig del Mas, 66650
Banyuls-sur-Mer, France

Some solitary dolphins reorient part or all of their social behavior towards
humans. Such dolphins often attract large numbers of people who wish to
observe them at close quarters or even interact with them. These encounters
may be rewarding for both the dolphin and the people concerned, but negative
outcomes, particularly for the dolphin, are common. This paper describes the
pattern of development of human-friendly dolphin situations and proposes a
"dolphin etiquette" and protocols for management options. The most critical
of these is the development of a situation-specific management plan with
official support for its implementation. The success of a management plan
will depend on an effective education program and the support of local
Batista, R.L.G., B.L. Bastos, R. Maia-Nogueira, M. dos Reis, and M. do
Socorro Santos. 2005. Rescue and release of two estuarine dolphins (_Sotalia
fluviatilis_; Gervais, 1853) found confined in a natural pool of the
Cachoeira River, Ilhéus, southern Bahia, Brazil. _Aquatic Mammals_

Aquatic Mammals Rescue Center-AMRC/Aquatic Mammals Research and Conservation
Society, Largo da Vitoria, 02/102. Edf. San Remo, CEP: 40130-110. Salvador,
Bahia, Brazil

The estuarine dolphin, _Sotalia fluviatilis_, is one of the least known
delphinids distributed on the Brazilian coast, and it is considered to be
"insufficiently known" by the World Conservation Union (IUCN, 2000) and the
Action Plan for Aquatic Mammals of Brazil (IBAMA, 2001). On 1 March 2003,
two estuarine dolphins were found confined in a natural pool of the
Cachoeira River, Ilhéus, southern Bahia, Brazil. They remained trapped in
the pool for nine days, so a rescue was launched on 10 March 2003 to return
them to deep water in the Pontal Bay, Ilhéus. Their capture was performed
with a 0.9-mm nylon net, which was 120 m in length, 6 m in depth, and 80 mm
in stretched mesh, through an encirclement technique. As soon as the
dolphins were removed from the net, a physical assessment was performed.
Both individuals were subadult males, with good body conditions, and normal
cardiac and respiratory rates. During the handling process, the animals were
treated preventively with 4 mg of Dexamethasone by intramuscular injection.
The dolphins were released successfully next to Pontal Bay and were
monitored for one hour. They found food resources soon after release, and a
restranding did not occur. Although there is no evidence that they
ultimately survived, since the possibility of death at sea without carcass
recovery cannot be ruled out, their chances of survival increased, at least
in the short term.
Guerrero-Ruiz, M.*, I. García-Godos, and J. Urbán R. 2005. Photographic
match of a killer whale (_Orcinus orca_) between Peruvian and Mexican
waters. _Aquatic Mammals_ 31(4),438-441. 

*Programma de Investigacion de Mamiferos Marinos, Departamento de Biologia
Marina, Universidad Autonoma de Baja California, Sur. A.P. 19-B, La Paz,
B.C.S. Mexico, C.P. 23081

Killer whales are widely distributed along the Pacific coast of Mexico, but
they are only occasionally seen in some areas of the southeast Pacific.
Although they are found on both coasts of the Baja California Peninsula,
killer whale distribution and movements have mostly been studied in the Gulf
of California. Records of this species are sporadic off Peru, and sightings
have been mainly anecdotal. On 27 March 2001, a pod of six killer whales was
observed during a pelagic survey at 12° 52′ S, 77° 53′ W, ca. 148 km off
Pucusana, Peru. Within the killer whale pod, a readily identifiable adult
male was present. Photographs of this male were checked for matches with the
Mexican killer whale catalog. During this process, a match was found with an
animal previously photographed two times in the Mexican Pacific, on 4 April
1988 in Magdalena Bay at 24° 18′ N, 112° 01′ W, and on 5 July 1994 in La
Paz Bay at 24°36′ N, 110°26′ W. The minimum distance between the Mexican
and Peruvian match reached a total of 5,535 km. The inter-hemispheric match
reported in this paper extends the already known maximum distance that
killer whales are able to travel, and also raises further questions in
relation to the population structure of the species due to its high capacity
of movement throughout the oceans and, in consequence, the potential
interaction between geographically distant populations.
Oviedo, L.*, N. Silva, L. Bermudez, and D.K. Odell. 2005. Distribution of
bottlenose dolphins (_Tursiops truncatus_) on the east coast of Isla
Margarita and the Los Frailes Archipelago, Venezuela. _Aquatic Mammals_

*Biotropica, Center for Research and Conservation of Tropical Biodiversity,
Caracas 1090, Venezuela

There have been few studies on the composition, distribution, and abundance
of cetaceans in Venezuelan waters. Opportunistic stranding and sighting data
revealed _Tursiops_, _Stenella_, _Delphinus_, and _Balaenoptera edeni_ in
the waters around Isla Margarita, Coche, Cubagua, and Los Frailes
Archipelago. All of these sites are located off the northeast coast of the
mainland of Venezuela in an area of coastal upwelling and complex submarine
topography. The purpose of this study was to conduct a preliminary
assessment of bottlenose dolphins and other cetaceans in this area. Data
were gathered from June 1999 through November 2000 using a land-based
platform (28 h) and a boat-based platform (26 surveys, totaling 121 h and
699 nmi). Data in relation to sea floor relief were analyzed using GIS
software. Complex topographical features, such as depressions and passes
located southwest of the study area, appear to limit the range of
_Tursiops_. Bottlenose dolphins commonly occur between Punta Ballenas and
Los Frailes Archipelago, where movements among those localities evidence a
great plasticity in two different environments, likely to be related to prey
distribution. No interspecific aggregation was recorded for bottlenose
dolphins, as observed in the central coast of the country with _Stenella
frontalis_ and _Tursiops truncatus_. This study is the first to document
cetacean habitat use around Isla Margarita and, with continued effort, will
be important not only for documenting Venezuelan cetaceans but also for the
assessment of potential impacts of local development, including ecotourism.

Watson, A.*, and L.E. Gee. 2005. Laryngeal displacement and asphyxiation by
a beheaded sheepshead (_Archosargus probatocephalus_) in a bottlenose
dolphin (Tursiops truncatus). _Aquatic Mammals_ 31(4), 447-452.

*Department of Physiological Sciences, College of Veterinary Medicine,
Oklahoma State University, Stillwater, OK 74078-2014, USA

A mature, 2.7-m male bottlenose dolphin (_Tursiops truncatus_) with a fish
tail protruding from its mouth was found dead on the northern Gulf of Mexico
coast near Galveston, Texas, on 26 February 1995. Necropsy revealed a large
and beheaded sheepshead (_Archosargus probatocephalus_) directly impacting
the base of the laryngeal goosebeak. The larynx was severely dislocated
rostroventrally into the oral cavity, which led to death by asphyxiation. An
isolated sheepshead head was recovered from the caudal thoracic esophagus.
Feeding strategies in dolphins of beheading fish and the sometimes fatal
ingestion of inappropriately large and/or spiny prey are discussed.
dos Santos, M.E.*, S. Louro, M. Couchinho, and C. Brito. 2005. Whistles of
bottlenose dolphins (_Tursiops truncatus_) in the Sado Estuary, Portugal:
Characteristics, production rates, and long-term contour stability. _Aquatic
Mammals_, 31(4),453-462.

*Unidade de Investigacao em Eco-Etologia, Instituto Superior de Psicologia
Aplicada, Rua Jardin do Tabaco 34, 1149-041 Lisboa, Portugal

This study focuses on the whistle characteristics and production patterns of
bottlenose dolphins (_Tursiops truncatus_) resident in the Sado Estuary,
Portugal. Recordings and observations were conducted inside the estuary and
in adjacent coastal waters using single hydrophones between 1987 and 2000.
In the groups sampled, the mean number of whistles emitted per minute per
animal was 0.28. The acoustic characteristics of a sample of 735 whistles
were measured and compared with data from other _Tursiops_ populations,
showing that, in a pattern of overall similarity, the whistles recorded in
the Sado are relatively long and the frequency range used is relatively
wide. Mean peak frequency was 9.2 kHz. About 30% of the whistles were
stereotyped, and remarkable stability was found in several contours over a
12-year period. No relation was found between dolphin group size and whistle
rate, suggesting some restriction in production; and no relation was found
between dolphin group size and the emission of different contours.
Significant variation was found between episodes of simple travel and more
aroused activities in terms of the production of whistles in general and
also of different whistle contours.
Lopatka, M.*, O. Adam, C. Laplanche, J. Zarzycki, and J-F Motsch. 2005. An
attractive alternative for sperm whale click detection using the wavelet
transform in comparison to the Fourier spectrogram. _Aquatic Mammals_,

*Laboratorie d'Images, Signaux et Systemes Intelligents (Lissi-iSnS),
University Paris 12, France

Although many mathematical and signal-processing tools exist, detection of
sperm whales based on their sound recordings proves somewhat difficult. This
paper presents some of the advantages of the wavelet transform and the
spectrogram in analyzing sperm whale clicks. The coefficients of the wavelet
transform and the short-time Fourier transform are used to provide a
representation of the intrinsic characteristics of the sound emissions of
the sperm whale. For detection, we propose a new parameter―Short-Time
Windowed Energy―that characterizes the particular shape in the
time-frequency/scale domain of sperm whale clicks. This paper illustrates
the resistance to noise of this parameter. In addition, thanks to new
processors, this algorithm, which was once lengthy in calculation time, can
be integrated easily in a real-time system.
Silva, J.M.*, and J.L. Silva Flávio, and I. Sazima. 2005. Two presumed
interspecific hybrids in the genus _Stenella_ (Delphinidae) in the tropical
West Atlantic. _Aquatic Mammals_,31(4),468-472. 

*Centro Golfinho Rotador, CP 49, 53990-000 Fernando de Noronha, Pernambuco,

We describe and comment on two aberrant individuals of the genus _Stenella_
from Fernando de Noronha Archipelago, tropical West Atlantic, which we
regard as interspecific hybrids. Each dolphin was found living with a large
group of spinner dolphins, _Stenella longirostris_. One of the aberrant
dolphins is a presumed hybrid between _S. longirostris_ and _S. attenuata_,
and the second one is possibly a hybrid between _S. longirostris_ and _S.
clymene_. Each of the hybrids was accompanied by a spinner female. The _S.
longirostris_ × _S. attenuata_ was first sighted as a calf and was
re-sighted several times over two years. This individual was recorded being
nursed by the female. The other hybrid was re-sighted a few times over three
Bossart, G.D.*, S. Ghim, M. Rehtanz, J. Goldstein, R. Varela, R.Y. Ewing, P.
A. Fair, R. Lenzi, B. Joseph, C.L. Hicks, L.S. Schneider, C.J. McKinnie,
J.S. Reif, R. Sanchez, A. Lopez, S. Novoa, J. Bernal, Jaime; M. Goretti, M.
Rodriguez, R.H. Defran, and A.B. Jenson. 2005. Orogenital neoplasia in
Atlantic bottlenose dolphins (_Tursiops truncatus_). _Aquatic Mammals_,

*Division of Marine Mammal Research and Conservation, Harbor Branch
Oceanographic Institution, 5600 US 1 North, Ft. Pierce, FL 34946, USA

This study describes lingual papillomas and squamous cell carcinomas (n=11)
and genital papillomas (n = 4) in Atlantic bottlenose dolphins (_Tursiops
truncatus_) evaluated from January 2000 to January 2005. Tumors were found
primarily in adult dolphins of both sexes living in free-ranging and captive
conditions. Three dolphins had multiple lingual tumors of mixed histological
type, consisting of papillomas and squamous cell carcinomas, suggesting
malignant transformation of the benign papillomatous lesions. To our
knowledge, this is the first report of oral papillomas in bottlenose
dolphins and concurrent oral neoplasia that included both sessile papilloma
and squamous cell carcinoma in the same dolphin. Additionally, it is the
first known report of genital papillomas in free-ranging bottlenose dolphins
from Atlantic coastal waters. The unusually high occurrence of related
benign and malignant orogenital epithelial neoplastic lesions in a short
period suggests that the lesions may represent one or more emerging
diseases. Preliminary evidence suggests that these tumors may be of
infectious etiology, possibly having an orogenital route of transmission.
Book Reviews: 
Nawojchik, R.* 2005. Marine Protected Areas of Whales, Dolphins, and
Porpoises: A World Handbook for Cetacean Habitat Conservation. Editor: Erich
Hoyt. Earthscan, London and Sterling, VA, USA. 2005. _Aquatic Mammals_,

*P.O. Box 335, Bradford, Vermont 05033, USA
Aguilar, A.* 2005. Marine Mammals of India. Kumaran Sathasivam. Universities
Press (India) Private Limited, Hyderabad. 2004. _Aquatic Mammals_,

*Department of Animal Biology, University of Barcelona, 08071 Barcelona,
Donovan, G*. 2005. Book Review: Whaling Around the World. Editor: Kathy
Happynook, World Council of Whales (WCW) Publications. _Aquatic Mammals_,

*Head of Science, International Whaling Commission, The Red House, 135
Station Road, Impington, Cambridge CB4 9NP, United Kingdom

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