Apologies to those of you receiving cross-postings.
The following are abstracts and the list of book reviews from the latest
issue (vol 31, issue 1) of Aquatic Mammals, which is the scientific, peer
reviewed journal of the European Association for Aquatic Mammals (EAAM).
These abstracts are provided as a courtesy to the EAAM and the journal
editor - Dr. Jeanette Thomas. More information on EAAM, membership, and
Aquatic Mammals may be found at the EAAM website: http://www.eaam.org.
Author guidelines and manuscript submission inquiries may also be directed
to: Dr. Jeanette Thomas, Department of Biological Sciences, Western Illinois
University-Quad Cities, 3561 60th Street, Moline, Illinois 61265, USA.
email: [log in to unmask], telephone: 309-72-9481, fax: 309-762-6989.
Thank you for your continued interest in these postings. Please do not
request reprints from the listserve editors or me. I have included the
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do not contact me to request an email address for an author; if it was
provided by the author of the article, it is already included here.
Regards,
Dagmar Fertl
Marine Mammal Biologist
Geo-Marine, Inc.
550 East 15th Street
Plano, Texas 75025 USA
972-423-5480
fax: 972-422-2736
[log in to unmask]
http://www.geo-marine.com
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Colegrove, K.M.*, D.J. Greig, and F.M.D. Gulland. 2005. Causes of live
strandings of northern elephant seals (Mirounga angustirostris) and Pacific
harbor seals (Phoca vitulina) along the central California coast, 1992-2001.
Aquatic Mammals 31(1):1-10.
*Veterinary Medical Teaching Hospital, University of California, One Shields
Avenue, Davis, CA 95616, USA
Between January 1992 and December 2001 a total of 1,277 northern elephant
seals (Mirounga angustirostris) and 940 Pacific harbor seals (Phoca
vitulina) were stranded live along the central California coast. By
examining medical records for each of the stranded seals, the primary cause
of stranding and the secondary factors contributing to stranding were
determined. The majority (88.3%) of animals were young born that year. The
most common causes of live strandings for elephant seals included
malnutrition (56.6%), Otostrongylus circumlitus infection (12.1%), and
northern elephant seal skin disease (9.8%). The most common causes of
strandings for harbor seals were malnutrition (51.8%), respiratory disease
(9.6%), and trauma (8.0%). Common secondary factors for strandings for both
elephant and harbor seals included human interaction, trauma, and ocular
disease. For both species of phocid, the highest prevalence of O.
circumlitus infection occurred in 1992 and 1993, years of a moderate El
Niño-Southern Oscillation event. Phocine herpesvirus-1 infection was a
common primary and secondary factor in harbor seal strandings, and the
highest prevalence occurred between 1994 and 1998. Human interference in
stranding events increased in the past ten years and is most commonly
reported on beaches near heavily populated areas.
***************************************************************
Greig, D.J.*, F.M.D. Gulland, and C. Kreuder. 2005. A decade of live
California sea lion (Zalophus californianus) strandings along the central
California coast: Causes and trends, 1991-2000. Aquatic Mammals 31(1):11-22.
*The Marine Mammal Center, Marin Headlands, 1065 Fort Cronkhite, Sausalito,
CA 94965, USA
Stranded marine mammals offer a unique sample of relatively inaccessible
wild animals that are more likely to represent the diseased segment of the
population and are easy to examine thoroughly. Examination of these animals,
therefore, offers a method to detect novel diseases in free-living aquatic
mammals. Diseases in marine mammals may reflect environmental changes such
as ocean pollution, prey shifts, and global warming. To detect spatial and
temporal trends in prevalence of such diseases, we reviewed records for
3,707 California sea lions (Zalophus californianus) that stranded live
between 1991 and 2000 along the central California coast. Reasons for
stranding were determined from a combination of clinical examinations,
hematology and serum biochemistry, radiography, gross necropsy,
histopathology, microbiology, and biotoxin assays. Over the ten years, 74%
of sea lions stranded in Santa Cruz, Monterey and San Luis Obispo Counties,
and 83% of these were admitted between May and October each year.
Malnutrition was the most common reason for stranding (32%), followed by
leptospirosis (27%), trauma (18%), domoic acid intoxication (9%), and cancer
(3%). Strandings caused by malnutrition were greatest during the El Niño
events of 1992, 1993, and 1998, while strandings caused by leptospirosis
accounted for over 60% of strandings in 1991, 1995, and 1999. Although
domoic acid was first reported in California sea lions in 1998, there was a
small stranding event in 1992 that, based on clinical examinations and
histopathology, was probably also caused by domoic acid. The observed
prevalence of cancer among stranded animals remained constant over the past
ten years at 3%.
***************************************************************
Born, E.W.*, M. Acquarone, L.Ø. Knutsen, and L. Toudal. 2005. Homing
behaviour in an Atlantic walrus (Odobenus rosmarus rosmarus). Aquatic
Mammals 31(1):23-33.
*Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk,
Greenland
An adult Atlantic walrus (Odobenus rosmarus rosmarus) male (31 years old in
2001) tracked by use of satellite telemetry in NE Greenland during four
seasons (1989, 1990/1991, 2000/2001, 2001) revealed a remarkably high
perennial tendency of homing and consistency of migration pattern. During
all four inshore summering periods (August to September), the animal used
only one terrestrial haul-out from which it made excursions to the same
general shallow water area (i.e., likely clam beds) in western Dove Bay (ca.
76° to 77° N). In different years, the size of the inshore foraging area
varied between 48 and 86 km2 in August, and between 136 and 385 km2 in
September. The inshore foraging period lasted ca. 69 days in 1989 and 1990,
but ca. 86 days in 2000 (no data for 2001). During fall 1989, 1990/1991 and
2000/2001, the walrus followed the same migration route in the Greenland Sea
north to the wintering grounds in the Northeast Water polynya (ca. 79° to
81° N). Apparently, this movement pattern was relatively independent of
annual variations in ice and temperature regimes. Offshore in the Greenland
Sea–Fram Strait area, the walrus occurred mainly in areas with dense ice
cover (> 90%). During both the inshore summer and offshore winter, the
animal dived to at least 250 m (maximum depth limit of the transmitter). The
tracking of this walrus, whose activity pattern was typical of male walruses
in the region, shows that this stenophagous species is a creature of habit
with a highly stereotypic movement pattern which apparently is influenced by
the location of predictable feeding, wintering, and mating areas.
*************************************************************
Kastelein, R.A.*, C. Staal, and P.R. Wiepkema. 2005. Food consumption and
body mass of captive harbor seals (Phoca vitulina). Aquatic Mammals
31(1):34-42.
*Sea Mammal Research Company (SEAMARCO), Julianalaan 46, 3843 CC Harderwijk,
The Netherlands
The food consumption (recorded as kg of individual fish species) of nine
male and six female captive harbor seals is described. This longitudinal
study is based on data originally archived for short-term husbandry
purposes. The chemical composition and caloric value of the diet were not
measured. Because caloric content of fish varies seasonally and annually,
and depends on the geographical region where it was caught, the average food
intake variations seen in this study may reflect the caloric content of the
diet. However, because the effects of season, age, gender, and reproductive
state are consistent in various seals, and all seals entered the study at
different times, and food was caught in different seasons and stored for
different lengths of time before being fed, the general patterns described
are believed to be independent of variation in caloric content of the diet.
There was a great deal of individual variation in the annual food
consumption of male harbor seals, but generally it increased from around 950
kg at the age of one year to around 1,200 kg (estimated at 98 × 105 kJ/year)
at the age of 13 years. The annual food consumption of the nonreproductive
female harbor seals also varied much among individuals, but generally
fluctuated around 1,000 kg (estimated at 82 × 105 kJ/year). Adult male and
female harbor seals had slightly different seasonal cycles in food
consumption. Reproduction (producing a pup and suckling it) increased the
degree of seasonal fluctuation in consumption by females. Immature animals
did not experience seasonal changes in food intake. During molting, the
seals usually lost weight. In males, molt occurred in August; and in
females, usually in July. Males and females grew rapidly between birth and
the age of 4 to 5 years. Thereafter, the growth rate decreased. Males
reached a maximum body mass of around 100 kg and females around 90 kg. A
negative relationship occurred between body mass and food intake when
expressed as a percentage of body mass.
****************************************************
Stockin, K.A.*, and I.N. Visser. 2005. Anomalously pigmented common dolphins
(Delphinus sp.) off northern New Zealand. Aquatic Mammals 31(1):43-51.
*Coastal-Marine Research Group, Institute of Natural Resources, Massey
University, Private Bag 102 904, North Shore MSC, Auckland, New Zealand
Anomalous pigmentations have been recorded in many cetacean species.
However, typically only one variation is reported from a population at a
time (e.g., an albino). Here we record a spectrum of pigmentation from
common dolphins (Delphinus sp.) off northern New Zealand. All-black,
dark-morph, pale-morph, and all-white individuals, as well as variations
between these have been recorded. Pale-coloured pectoral flippers are
prevalent, and a number of individuals with white "helmets" have been
observed.
*******************************************************
Larkin, I.L.V.*, T.S. Gross, and R.L. Reep. 2005. Use of faecal testosterone
concentrations to monitor male Florida manatee (Trichechus manatus
latirostris) reproductive status. Aquatic Mammals 31(1):52-61.
*Department of Physiological Sciences, Box 100144 HSC, 1600 SW Archer Road,
University of Florida, Gainesville, FL 32610, USA
The Florida manatee is an aquatic herbivore found in tropical, coastal
waterways. This endangered species becomes sexually mature at 2 to 5 years
of age. Reproductively active adults often form mating herds, consisting of
one focal female pursued by several males. Understanding Florida manatee
(Trichechus manatus latirostris) reproductive biology is important for
establishing population models, making management decisions, and recognizing
differences between healthy and unhealthy states. Field and necropsy data
indicate that manatees do not have well-defined breeding seasons and are
diffuse in their breeding patterns. They exhibit reproductive activity
throughout the warm months, having peaks during spring and lulls during
winter months. Monitoring male testosterone concentrations in both wild and
captive populations can provide direct comparisons of physiological data on
the reproductive status of these animals. The objectives were to (1)
validate the use of a commercial testosterone radioimmunoassay kit for
measuring faecal concentrations of the parent steroid in male Florida
manatees, (2) identify biologically meaningful distinctions between gender
and levels of maturation measured with faecal testosterone concentrations,
and (3) identify seasonal hormone fluctuations. Of individual adult mean
values, 62% of males had higher testosterone concentrations than all adult
females measured. The total range of male faecal testosterone concentrations
measured was 120.8–36,240 ng/g dry weight; whereas, females ranged
120.8–5,919 ng/g. Seasonal fluctuations in hormone concentrations were
observed in captive manatees with peaks during spring and/or fall,
supporting the hypothesis that Florida manatees are a diffusely seasonal
breeding species. Results indicate that radioimmunoassays of faecal hormones
can be a useful, non-invasive tool for monitoring testosterone
concentrations in Florida manatees, enhancing the accuracy of current
monitoring methods of using behavior or morphometrics. This can be
particularly helpful in field sites where animals are not captured for
health assessments and water clarity limits observations of the animals,
which is typical of most water bodies manatees inhabit.
****************************************************
Logerwell, E.A.*, and L.E. Schaufler. 2005. New data on proximate
composition and energy density of Steller sea lion (Eumetopias jubatus) prey
fills seasonal and geographic gaps in existing information. Aquatic Mammals
31(1):62-82.
*Alaska Fisheries Science Center, 7600 Sand Point Way, NE, Seattle, WA
98115, USA
Energy density data of prey items are necessary to estimate food
requirements of predators. The goal of this study was to provide proximate
composition and energy density information for Steller sea lion (Eumetopias
jubatus) prey species where there are seasonal and/or geographic gaps in the
existing data. Opportunistic collections were made on board National Oceanic
and Atmospheric Administration fisheries research surveys in the Aleutian
Islands region, eastern Bering Sea, and Gulf of Alaska, targeting particular
species of interest. Proximate analyses were conducted in the laboratory and
energy density was calculated from lipid and protein content. Pacific
herring, sand lance, and rockfish were found to contain the highest amount
of lipid and provide the most energy. Atka mackerel, surf smelt, capelin,
salmon, sandfish, pollock, yellow Irish lords, Pacific cod, squid, skates,
and rock sole had intermediate energy densities. Smooth lumpsucker and
snailfish were found to contain the least amount of energy. This study is
the first to provide proximate composition data for adult pollock during the
nonspawning seasons in the Gulf of Alaska and Aleutian Islands region. This
study also provides the first proximate composition data for juvenile
pollock in the Aleutian Islands region and eastern Bering Sea, and for
Pacific cod in the eastern Bering Sea. This study fills another critical gap
by presenting the only information on proximate composition of adult Atka
mackerel, one of the most important prey of Steller sea lions in the
Aleutian Islands region. These improvements in the seasonal and geographic
coverage of fish proximate and energy density data will allow for seasonally
and geographically specific estimates of Steller sea lion prey requirements,
a necessary improvement over annual estimates made previously. These data
can also contribute to bioenergetic modeling of prey requirements of other
predators in Alaska such as groundfish, fur seals, and marine birds.
************************************************************
Visser, I.N.* 2005. First observations of feeding on thresher (Alopias
vulpinus) and hammerhead (Sphyrna zygaena) sharks by killer whales (Orcinus
orca) specialising on elasmobranch prey. Aquatic Mammals 31(1):83-88.
*Orca Research Trust, P.O. Box 1233 Whangarei, New Zealand
Killer whale (Orcinus orca) predation on elasmobranchs (sharks and rays) is
not often reported. In New Zealand waters, killer whales captured and ate
thresher (Alopias vulpinus) and smooth-hammerhead (Sphyrna zygaena) sharks.
Both species were not reported previously as prey of killer whales. These
observations help support the idea that elasmobranchs are a main prey type
for New Zealand killer whales; ten species of elasmobranchs are now recorded
as prey for this population.
*********************************************************
Brook, F.M.*, and R.E. Kinoshita. 2005. Controlled unassisted breeding of
captive Indo-Pacific bottlenose dolphins, Tursiops aduncus, using
ultrasonography. Aquatic Mammals 31(1):89-95.
*Department of Optometry and Radiography, The Hong Kong Polytechnic
University, Hong Kong
Ultrasonographic monitoring of folliculogenesis and prediction of ovulation
was used for ten years to control breeding in a group of Indo-Pacific
bottlenose dolphins (Tursiops aduncus) at Ocean Park, Hong Kong, where male
and female dolphins were housed separately from 1991. When folliculogenesis
was identified in a selected female, the cycle was monitored until ovulation
was predicted within the next 12 to 24 h; a male was selected and then
placed with the female overnight.
Ultrasonography was repeated the next morning to determine ovulation. If
ovulation had occurred, the animals were separated; if not, the pair
remained together until ovulation was confirmed. Ultrasonography was
subsequently used to monitor the development of the corpus luteum and to
identify pregnancy. This procedure was conducted 11 times between 1993 and
2003.
In nine cases, ovulation was predicted accurately and occurred within 24
hours. In two cases, ovulation occurred within two to four days of the
predicted date. In ten cases, pregnancy ensued. To date, nine calves have
been born live after gestation lengths of 349-382 days.
***********************************************************************
Rogers, T.L.* 2005. Influences of female pupping habitat and maternal care
on the vocal repertoire size of male phocid seals. Aquatic Mammals
31(1):96-103.
*Australian Marine Mammal Research Centre, Zoological Parks Board of NSW and
Veterinary Faculty, University of Sydney, Mosman, NSW 2088, Australia
Phocid life history and vocal repertoire size data gathered from the
literature were examined with independent contrasts analyses to assess
whether there is a significant relationship between sexual selection and
vocal repertoire size. Investigations showed that the degree of polygyny
does not influence vocal repertoire size of males, but was strongly
influenced by the strategy of maternal care adopted by females. Species
where females remain with their pups while nursing ("stay-at-home mums")
have males with simple crude vocal repertoires used in male-male agonistic
interactions. In these species, male elephant (Mirounga sp.), grey
(Halichoerus grypus), crabeater (Lobodon carcinophagus), and hooded
(Cystophora cristata) seals generally have greater access to estrus females
while they are still hauled out ashore. In species where females continue to
go to sea while raising their pups ("working mums"), males have broader
advertising vocal repertoires. The stability of the haul-out platform during
breeding used by the females makes a further impact, however. Where
"working-mums" breed in unstable pack ice, males have little chance of
predictably locating routes used by estrus females while traveling to and
from feeding grounds. These species, the leopard (Hydrurga leptonyx), Ross
(Ommatophoca rossii), bearded (Erignathus barbatus), and ribbon
(Histriophoca fasciata) seals, have intermediate- sized repertoires used in
long-range underwater acoustic displays (scattergun advertising). The third
group, the Weddell (Leptonychotes weddellii), harp (Pagophilus
groenlandicus), harbour (Phoca vitulina), and ringed (Pusa hispida) seals,
have the largest vocal repertoires. In these species, "working-mums" breed
in stable environments, so males perform underwater acoustic advertisement
displays (local advertising) in the vicinity of predictable feeding routes
used by estrus females. Because these signals are not constrained by
propagation, a large array of sound types have developed.
***********************************************************
Scott, N.J.*, and E.C.M. Parsons. 2005. A survey of public opinion on seal
management in southwestern Scotland. Aquatic Mammals 31(1):104-109.
*Department of Life Sciences, Stirling University, Stirling, Scotland
To assess public opinion on the level of protection given to seals in
Scotland and on the controversial issue of seal culls, a survey was
conducted in south-western Scotland at various locations in the rural county
of Argyll and the city of Glasgow in 2001. This study found that most
participants were of the opinion that the current level of protection given
to seals was sufficient. In addition, the survey found that the majority of
the participants were against the concept of seal culling to protect
fisheries. Analysis of responses showed that both female and younger
participants were more likely to be against the introduction of seal culls,
but, surprisingly, neither interest in marine or environmental issues nor
the occupation of the participants, including involvement in the fishing
industry, affected the level of support or opposition. Numerous responses
were given by participants to support and qualify their opinions, and these
are summarised.
********************************************************
Van Opzeeland, I.C.*, P.J. Corkeron, T. Leyssen, T. Similä, and S.M. Van
Parijs. 2005. Acoustic behaviour of Norwegian killer whales, Orcinus orca,
during carousel and seiner foraging on spring-spawning herring. Aquatic
Mammals 31(1):110-119.
*Biology Department, University of Groningen, P.O. Box 14, 9750 AA Haren,
The Netherlands
Norwegian killer whales (Orcinus orca) use different techniques to forage on
spring-spawning herring. Two of the commonly observed techniques are
carousel feeding, a cooperative feeding method, and seiner feeding, a
noncooperative method. During seiner foraging, large groups of whales forage
on herring discards around the nets or on discarded by-catch of fishing
boats. Very little is known about the acoustic behaviour during these
foraging contexts. The aim of this study was to examine possible differences
in killer whale acoustic behaviour during both foraging contexts using
simple sound analysis techniques. Calling, echolocation, and tail-slap
activities were measured and compared between foraging contexts. Of these,
calling and tail-slap activities were higher during carousel feeding,
whereas echolocation activity increased with the number of individuals,
irrespective of foraging context. No call types were used exclusively during
a particular foraging context. A difference in mean occurrence of one call
type was detected; call type N21 occurred more often during seiner foraging
than during carousel foraging contexts. We suggest that the sequence of call
types, rather than the use of isolated call types, is of greater importance
in the coordination of group movements during carousel foraging.
*************************************************************
Stockin, K.A.*, and E.A. Burgess. 2005. Opportunistic feeding of an adult
humpback whale (Megaptera novaeangliae) migrating along the coast of
southeastern Queensland, Australia. Aquatic Mammals 31(1):120-123.
*Coastal-Marine Research Group, Institute of Natural Resources, Massey
University, Private Bag 102 904, North Shore MSC, Auckland, New Zealand
In the austral winter of July 2004, off southeastern Queensland, Australia,
we observed apparent feeding by an adult humpback whale (Megaptera
novaeangliae) in association with Indo-Pacific bottlenose dolphins (Tursiops
aduncus). This is the first documented case of an adult humpback whale from
the southern hemisphere Group V stock feeding along the migratory corridor.
This observation also represents the first published record of a humpback
whale feeding in association with Indo-Pacific bottlenose dolphins.
*******************************************************
Clarke, R.* 2005. Male nipples in blue and fin whales and their absence in
sperm whales. Aquatic Mammals 31(1):124-132.
*Apartado 40, Pisco, Peru
During the Antarctic Whaling Season of 1947-1948, searches in a series of
foetal and postnatal male blue and fin whales gave information on variation,
morphology, and morphometry of the nipples sunk in grooves posterior to the
penis. A review indicates that male nipples occur in most, probably all,
whalebone whales. In 1947-1948, no nipples were found in six postnatal sperm
whales, and further evidence, from 41 male foetal sperm whales, and 1,269
male postnatal sperm whales examined in the Southeast Pacific in 1958 to
1962, showed that male sperm whales do not possess nipples.
*****************************************
Mattson, M.C.*, J.A. Thomas, and D. St. Aubin. 2005. Effects of boat
activity on the behavior of bottlenose dolphins (Tursiops truncatus) in
waters surrounding Hilton Head Island, South Carolina. Aquatic Mammals
31(1):133-140.
*Department of Biological Sciences, Western Illinois University-Quad Cities,
3561 60th Street, Moline, IL 61265, USA
During the summer of 1998, the effects of boat activity on the behavior of
bottlenose dolphins (Tursiops truncatus) were investigated using 52
shore-based surveys along Hilton Head Island, South Carolina. Temporal
autocorrelation indicated data collected on most variables should be
analyzed in 6-min intervals. Responses to boats were categorized as "no
response," "behavioral response," "change in direction of movement," or
"change in both behavior and direction." Multiple boats had a greater
influence on dolphin behavior and movement than the presence of a single
boat. Dolphin-watching boats, motorboats, shrimp boats, and jet skis
affected the group size and behavior of dolphin groups. Dolphin groups
responded to dolphin-watching boats during 20% of observations, mainly with
a change in both behavior and direction of movement. Motorboats caused a
response in dolphins during 55% of observations, with a change in behavior
or both behavior and direction. Jet skis had a more dramatic effect on
dolphin groups, with 56% of groups changing their behavior and 11% changing
both their behavior and direction. Shrimp boats always elicited a response.
Dolphin groups changed both their behavior, and direction of movement to
follow and feed behind these boats. In contrast, ships rarely caused a
response, with groups changing their behavior but not their direction in 11%
of observations. As the number of boats in the Hilton Head area increased,
dolphin groups heightened responses—that is, changed both behavior and
direction of movement. These boat-related effects on bottlenose dolphin
behavior are considered "harassment" under the U.S. Marine Mammal Protection
Act (1972) and should be scrutinized by agencies responsible for public
education and enforcement of protective legislation.
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Book Reviews:
Fairfield-Walsh, C. 2005. Book Review: The world of whales, dolphins, &
porpoises: Natural history & conservation. Author: T. Martin. Aquatic
Mammals 31(1):141-142.
*National Marine Fisheries Service, Southeast Fisheries Science Center,
Miami, Florida, USA
**************************************************************
Kraus, S. 2005. Book Review: Right whales: Natural history and conservation.
Author: P. Clapham. Aquatic Mammals 31(1):143.
*New England Aquarium, Boston, Massachusetts, USA
************************************************************************
Kenney, R.D. 2005. Book Review: Marine mammals of the North Atlantic.
Author: C.C. Kinze. Aquatic Mammals 31(1):144-146.
*University of Rhode Island, Graduate School of Oceanography, Narragansett,
Rhode Island, USA
[log in to unmask]
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de Olivera Santo, M.C. 2005. Book Review: Guia de Estudo de Cetaceos. Volume
1. Interacoes com Actividades de Pesca. Author: A.P.M. Di Beneditto. Aquatic
Mammals 31(1):147-148.
*Prjeto Atlantis & Instituto de Biologia da Conservacao, San Paulo, Brazil
**********************************************************************
Visser, I.N. 2005. Book Review: Orca: Visions of the killer whale. Author:
P. Knudtson. Aquatic Mammals 31(1):149.
*Orca Research Trust, P.O. Box 1233 Whangarei, New Zealand
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