Dear Marmam and ECS subscribers,
Apologies to those of you who will receive cross postings. The following are
abstracts from the most recent issue of _Aquatic Mammals_, journal of the
European Association for Aquatic Mammals (EAAM). These abstracts are posted
as a courtesy to the EAAM and the journal editor Dr. Jeanette Thomas.
Information on the EAAM and _Aquatic Mammals_ (e.g., past abstracts,
subscriptions, author guidelines) may be found at the EAAM website:
http://eaam.org. The journal editor may also be contacted regarding
inquiries about _Aquatic Mammals_:
Dr. Jeanette Thomas, Department of Biological Sciences, Western Illinois
University-Quad Cities, 3561 60th Street, Moline, Illinois 61625, USA;
[log in to unmask]; phone: 309-762-9841; fax: 309-762-6989.
Please note below that an address is provided for the corresponding author
to whom reprint inquiries, etc. should go to. No email addresses were
provided in the journal for these authors.
Thank you for your continued interest in these postings.
Regards,
Dagmar Fertl
Marine Mammal Biologist
Geo-Marine, Inc.
550 East 15th Street
Plano, Texas 75025 USA
[log in to unmask]
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Blomqvist, C.,* and M. Amundin. 2004. An acoustic tag for recording
directional pulsed ultrasounds aimed at free-swimming bottlenose dolphins
(_Tursiops truncatus_) by conspecifics. _Aquatic Mammals_ 30(3):345-356.
*Department of Biology, IFM, University of Linkoping, S-581 83 Linkoping,
Sweden
We developed an acoustic tag, called MOSART (MObile Submersible Acoustic
Recorder of Transients), for recording directional social pulses produced by
a bottlenose dolphin (_Tursiops truncatus_). The tag was attached to the
dorsal fin of two dolphins by means of suction cups. Two adult bottlenose
dolphins at the Komardens Djurpark, Sweden, were trained to carry the tag
comfortably through a desensitising program. The tag included two envelope
click-detectors, each with a narrow bandpass filter, centred at 120 and 70
kHz, respectively. The duration of the original pulses and their relative
amplitude within the two filter frequency bands were retained. The amplitude
differences between the two filter bands reflected changes in the source
frequency spectrum and/or the position of the tag hydrophone in the incoming
sound beam. The tag recorded "echolocation click trains," "slow and
irregular pulses," and "pulse bursts" with varying amounts of energy in both
frequency bands. The peak amplitude and duration of clicks in "echolocation
click trains" and in "slow and irregular pulses" were logged correctly;
however, the tag recorder had more difficulties in handling the complex
pulses in the aggressive "pulse bursts," where the duration of the
individual pulses could not be determined. Still, the amplitude and the
pulse repetition rate could be measured. The possible impact of the tag was
investigated by analysing the dolphin's behaviours (12 categories), sounds
(3 categories), preferred location in the pool, and respiration intervals.
Only four of the behaviours and one preferred location in the pool showed
significant differences among pre-tag baselines, tag periods, and post-tag
follow-ups, suggesting that the tag had only a minor impact on the dolphin.
We describe and discuss the tag and its capacity to record different pulsed
sounds.
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Acevedo-Gutierrez, A.*, and S.C. Stienessen. 2004. Bottlenose dolphins
(_Tursiops truncatus_) increase number of whistles when feeding. _Aquatic
Mammals_ 30(3):357-362.
*current address: Department of Biology, Western Washington University,
Bellingham, WA 98225-9160, USA
We examined the hypothesis that dolphins increase their rate of sound
production during feeding events to recruit new individuals. We recorded
135.5 min of underwater sounds from bottlenose dolphins (_Tursiops
truncatus_) near Isla del Coco, Costa Rica. Data were collected from eight
feeding grounds and three nonfeeding groups. We classified sounds as
whistles, click trains, or pulse bursts. The number of whistles per min per
dolphin was higher in feeding grounds than in nonfeeding groups. More
whistles than click trains or pulse bursts were produced when dolphins were
feeding. On the other hand, there was no difference in the proportion of
each sound type produced when dolphins were not feeding. New dolphins joined
the feeding events for which we recorded dolphin sounds. Results supported
the hypothesis that dolphin group size increases in response to an increase
in the number of whistles by conspecifics; however, confounding factors,
such as the use of specific feeding calls, need to be accounted for to
support the increased sound-rate hypothesis.
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Kreb, D.*, and K.D. Rahadi. 2004. Living under an aquatic freeway: Effects
of boats on Irrawaddy dolphins (_Orcaella brevirostris_) in a coastal and
riverine environment in Indonesia. _Aquatic Mammals_ 30(3):363-375.
*University of Amsterdam, Institute for Biodiversity and Ecosystem
Dynamics/Zoological Museum, P.O. Box 94766, 1090 GT Amsterdam, The
Netherlands
Interactions between boats, and coastal and freshwater Irrawaddy dolphins
(_Orcaella brevirostris_), were studied in East Kalimantan, Indonesia,
during 2001. The goal was to determine the conditions under which dolphins
reacted to boats and to recommend conservation actions. Both coastal and
freshwater Irrawaddy dolphins surfaced less in the presence of boats, but
the avoidance reaction lasted longer for the river dolphins. River dolphins
surfaced significantly less often in the presence of motorized canoes (<40
hp), speedboats (40-200 hp), and container tugboats (>1,000 hp). Coastal
dolphins only reacted to speedboats, and only when they approached at a 50-m
distance. River dolphins reacted within a maximum distance of 250 m before
and 300 m after a speedboat passed. Besides surfacing changes, river
dolphins actively avoided container tugboats. The strength of reactions did
not depend on the dolphins' behavior, group size, or age. Hypersensitivity
by river dolphins to intensive boat traffic could explain the different
responses between coastal and river dolphins. To prevent dolphin
displacement from their core areas, an action plan currently is being
developed by a nongovernmental organization in cooperation with Indonesian
governmental institutions and residents. Speedboat owners will be urged to
reduce boat speed in areas indicated on sign boards.
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Reyes, L.M.*, and P. Garcia-Borboroglu. 2004. Killer whale (_Orcinus orca_)
predation on sharks in Patagonia, Argentina: A first report. _Aquatic
Mammals_ 30(3):376-379.
*Universidad Nacional de la Patagonia San Juan Bosco, Boulevard Brown 3700,
(9120) Puerto Madryn, Chubut, Argentina
On 21 December 1998, four killer whales (an adult male, two females or
immature males, and one juvenile) attacked a group of sevengill sharks
(_Notorhynchus cepedianus_) off the coast of Caleta, Malaspina, Chubut,
Argentina. Persecution catches, and tossing behavior were performed by the
two females or immature males in the inlet. Next day, carcasses of several
sharks were found on the beach adjacent to the attack area. Seven of them
were intact and sized approximately 2.5 m in length. The presence of
complete sevengill shark carcasses on the beach suggests that they were
attempting to avoid capture by the killer whales by stranding on the beach.
Attacks on sevengills by killer whales in Caleta Malaspina are frequent in
some years, especially from mid-December to mid-January when the sevengill
seems to use the inlet as a nursery ground. The observation of the same male
feeding both on pinnipeds in Peninsula Valdes and on sharks in Caleta
Malaspina may indicate that at least some groups in the Southwestern
Atlantic could regularly feed on both fish and marine mammals. This is the
first report of an attack of killer whales on sharks off the coast of
Patagonia, and the first report of tossing behavior in sharks.
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Griffin, R.B.*, and N.J. Griffin. 2004. Temporal variation in Atlantic
spotted dolphin (_Stenella frontalis_) and bottlenose dolphin (_Tursiops
truncatus_) densities on the west Florida continental shelf. _Aquatic
Mammals_ 30(3):380-390.
*Mote Marine Laboratory, Center for Marine Mammal and Sea Turtle Research,
Offshore Cetacean Ecology Program, 1600 Ken Thompson Parkway, Sarasota, FL
34236, USA
We surveyed Atlantic spotted dolphins (_Stenella frontalis_) and bottlenose
dolphins (_Tursiops truncatus_) in an area of the west Florida continental
shelf (82 degrees to 84.5 degrees W and 26 degrees to 28 degrees N) from
November 1998 to December 2001. Objectives were to estimate relative
abundances of these two species and test for seasonal and interannual
variations in distribution. Monthly surveys were conducted over a three-year
period between the coast and the 180 m depth contour. Abundances of Atlantic
spotted dolphins and bottlenose dolphins were estimated using the software
program Distance. Sightings from monthly surveys were pooled by years and by
seasons within a year. Significant seasonal variations in Atlantic spotted
dolphin densities were repeated across years, with lower abundances during
the warm season (June-October), and higher densities during the cool season
(November-May). Atlantic spotted dolphin densities significantly decreased
during 2000, while bottlenose dolphin density trends were not apparent.
These trends continued into 2001, suggesting differential species response
to environmental variation may affect changes in cetacean community
structure over relatively short temporal scales.
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Wedekin, L.L.*, Daura-Jorge, F.G., and P. Simoes-Lopes. 2004. An aggressive
interaction between bottlenose dolphins (_Tursiops truncatus_) and estuarine
dolphins (_Sotalia guianensis_) in southern Brazil. _Aquatic Mammals_
30(3):391-397.
*Laboratorio de Mamiferos Aquaticos, Departamento de Ecologia e Zoologia,
Universidade Federal de Santa Catarina (UFSC), Campus Universitario,
Florianopolis SC 88040-900, Brazil
For the first time we report on an aggressive interaction between wild
bottlenose dolphins (_Tursiops truncatus_) and estuarine dolphins (_Sotalia
guianensis_) observed in Baia Norte, southern Brazil. Three bottlenose
dolphins aggressively herded a _Sotalia guianensis_ calf, which was the main
target of the aggressive and threatening behaviours of the bottlenose
dolphins. Another two to four adult _S. guianensis_ were involved in the
interaction and were constantly chased by the bottlenose dolphins. After
approximately two hours, the bottlenose dolphins left the calf and the area,
and no dead or wounded animals were seen afterwards. We provide a detailed
spatial and temporal description of the interaction, and discuss the
potential causes of this event.
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Bristow, T.* 2004. Changes in coastal site usage by bottlenose dolphins
(_Tursiops truncatus_) in Cardigan Bay, Wales. _Aquatic Mammals_
30(3):398-404.
*42 Briton Way, Wymondham, Norfolk NR18 0TT
A shore-based study has been conducted for over 14 years of a coastal
population of bottlenose dolphins (_Tursiops truncatus_) that frequent New
Quay Bay. Analysis of year-round observations for the years 1997, 2001, and
2002 are presented for the first time and are set in context with results
from the years 1989-1996 and 1998-2000, which were the subject of earlier
papers. The annual frequency of dolphin sightings in days per year with
comparable with previous studies. The results for 1997 are in line with
observations made in the period 1989 to 1999, both in terms of group size
frequency distribution, average monthly group size, and number of sightings
of groups with small calves. The results for 2001 and 2002 confirm the
significant decline in dolphin group size first noted in the year 2000, with
a steep decline in both average monthly group size and monthly maximum group
size. In addition, there was a corresponding decline in the incidence of
groups containing small calves. In 2002, the number of recognised
individuals seen was also reduced.
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Werth, A.J.* 2004. Functional morphology of the sperm whale (_Physeter
macrocephalus_) tongue, with reference to suction feeding. _Aquatic Mammals_
30(3):405-418.
*Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA 23943,
USA
Gross and microscopic examination of the tongue and hyolingual apparatus of
the sperm whale (_Physeter macrocephalus_) revealed numerous distinct
differences from those of other toothed whales and dolphins, largely
reflecting the tongue's atypical position, relations, and size, and its
primarily role in suction ingestion, rather than prey prehension or
transport, as in many other odontocetes. Unlike other odontocetes, the sperm
whales has a short, wide tongue that is uniquely situated at the rear of the
open oral cavity. Since the tongue does not extend to the tooth row, which
runs along the elongated median mandibular symphysis, it cannot easily
reorient grasped prey items, yet it can position them to be swallowed or
sucked directly into the oropharyngeal opening. The scarcity of intrinsic
lingual musculature (_m. lingualis proprius_), coupled with the relatively
large paired extrinsic muscles inserting into the tongue -- notably the _m.
hyoglossus_, whose profuse fibers comprise much of the tongue root, and the
_m. genioglossus_ -- suggests the tongue mainly undergoes positional, rather
than shape, changes as it is retracted by the hyoid to generate negative
intraoral pressures to capture and ingest prey items via suction. The tongue
possesses numerous longitudinal folds or plicae, but almost no free tip: its
slightly convex dorsum bears deep fissures and few sensory receptors in a
multilayered and predominantly aglandular horny epithelium.
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Druot, V.*, A Gannier, and J.C Goold. 2004. Diving and feeding behaviour of
sperm whales (_Physeter macrocephalus_) in the northwestern Mediterranean
Sea. _Aquatic Mammals_ 30(3):419-426.
*GREC, 741 chemin des Moyennes Breguieres, BP715, 06633 Antibes Cedex,
France
Sperm whale (_Physeter macrocephalus_) is one of the most common cetacean
species inhabiting the western Mediterranean Sea. The aim of this study was
to describe the dive cycle of sperm whales in this region and gain insight
into their foraging activity. Dedicated summer field seasons were conducted
from 2001-2003. Visual and acoustic measures were undertaken and their
relationships analyzed. The measures included surface/dive periods, blow
time, distance traveled, timing of clicks & creak activity, and inter-pulse
interval measurements of sperm whale clicks. The whales exhibited dive cycle
parameters consistent with those measured in other parts of the world:
approximately 45 min dive duration, 9 min surface period (i.e., inter-dive
interval), with 5 blows/min, and 1.3 nmi horizontal displacement between
dives. An average of 25 creaks per dive were registered. Whale body size
appeared to be significantly related with both the number of creaks per dive
and the dive time at which the first creak occurred, suggesting that larger
whales may increase their prey intake and the deeper water layers than
smaller whales. The timing of the first creak and the last click of the dive
(around 6 min after fluke-up, and just before the surfacing, respectively)
suggest a foraging depth of between 500 and 800 m, based on known descent
and ascent rates.
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Maniscalo, J.M., K. Wynne, K.W. Pitcher, M.B. Hanson, S.R. Melin, and S.
Atkinson. 2004. The occurrence of California sea lions (_Zalophus
californianus_) in Alaska. _Aquatic Mammals_ 30(3):427-433.
A total of 52 (25 male, 5 female, and 22 undetermined) California sea lions
(_Zalophus californianus_) have been reported in Alaska during the past
three decades, with an increasing presence in recent years. They have been
observed during all seasons of the year, although most often during the
spring. The presence of California sea lions in Alaska was correlated with
increasing populations within their southern breeding range. There was no
correlation between the number of sightings in Alaska and El Nino years.
This compilation includes the northernmost (60 degrees 46'N, n=1) and
westernmost (170 degrees 07' W, n=2) sightings for this species
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Bossart, G.D.*, R.A. Meisner, S.A. Rommel, J.D. Lightsey, R.A. Varela, and
R.H. Defran. 2004. Pathologic findings in Florida manatees (_Trichechus
manatus latirostris_). _Aquatic Mammals_ 30(3):434-440.
*Division of Marine Mammal Research and Conservation, Harbor Branch
Oceanographic Institution, 5600 US 1 North, Ft. Pierce, FL 34946, USA
This report describes pathologic findings associated with mortality in
Florida manatees (_Trichechus manatus latirostris_)(n=68) between January
1996 and January 2004. The most frequent causes of death among these Florida
manatees were trauma (47%), cold stress syndrome (CSS)(18%),
inflammatory/infectious disease (12%), and suspected brevetoxicosis (7%).
Probably all deaths due to trauma, as well as some, and perhaps many, cases
of CSS, may be regarded as anthropogenic, reinforcing the need for
conservation and management strategies to mitigate these impacts on this
endangered species. Cause of death was determined in a high proportion (94%)
of sample cases, demonstrating the importance of performing timely gross and
microscopic necropsy examinations on marine mammals.
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Castro, C.* 2004. Encounter with a school of pygmy killer whales (_Feresa
attenuata_) in Ecuador, southeast tropical Pacific. _Aquatic Mammals_
30(3):441-444.
*Pacific Whale Foundaiton, Asuncion 529 y Av. America. Edificio Cajiao, 4to.
Piso, Casilla 17-21872, Quito-Ecuador
On 1 September 2003, a school of about 70 pygmy killer whale (_Feresa
attenuata_) of several sizes (lengths varying from 1 to 2.5 m approximately)
was sighted. The sighting was made around the La Plata Island (01 degrees
34'S, 80 degrees 99'W), Machalilla National Park, Ecuador, at a depth of
about 47 m.
The school of dolphins was traveling at a speed of around 30 km/h. During
the whole length of the observation, while the animals were traveling, they
conducted running leaps and hard splash with their whole bodies outside of
the water. On some occasions, their heads were outside of the water and they
were bowriding in the waves produced by the boat. Individuals of about 1 m
in length were observed; these were probably calves.
We observed the individuals staying close together in the bow area, and the
sounds they produced were audible above the water. The length of the
whistles was around 5 s. The species was observed at a 3 km distance form
the Isla de la Plata and about 33 km from the continental coast of Ecuador.
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Book Reviews:
-------------
Kastelein, R.A.* CRC Handbook of Marine Mammal Medicine, Eds. L. Dierauf and
F. Gulland, pages 445-446.
*SEAMARCO, Julianalaan 46, 3843 CC Harderwijk, The Netherlands
--------------
Jefferson, T.A.* Walker's Marine Mammals of the World, R.M. Nowak, pages
447-448.
*Southwest Fisheries Science Center, NMFS, 8604 La Jolla Shores Drive, La
Jolla, CA 92037, USA
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