ArticlePDF Available

The Philippine Marine Mammal Strandings from 1998 to 2009: Animals in the Philippines in Peril?


Abstract and Figures

A well-maintained marine mammal stranding data-base can be an invaluable tool in understanding not only strandings but also changes in the marine environment. This study aimed to examine the fol-lowing aspects of marine mammal strandings in the Philippines: species composition, temporal (i.e., frequency of stranding per year and seasonality) and spatial (i.e., frequency of stranding per region and province) variation, proportions of alive or dead specimens, and stranding hotspots. In 2008, a sys-tematic collection of data on strandings, including out-of-habitat incidents, resulted in an initial 12-year database—from 1998 to 2009. A total of 178 strand-ing events were recorded: 163 single, 10 mass, and 5 out-of-habitat strandings, with an average of 15 observed stranding events annually. Twenty-three of the 28 confirmed species of marine mammals in the Philippines were recorded to strand, including first-recorded specimens for the Indo-Pacific bot-tlenose dolphin (Tursiops aduncus), pygmy sperm whale (Kogia breviceps), and Longman's beaked whale (Indopacetus pacificus). The top five most frequent species to strand included spinner dol-phin (Stenella longirostris) (n = 26), short-finned pilot whale (Globicephala macrorhynchus) (n = 14), melon-headed whale (Peponocephala electra) (n = 13), Risso's dolphin (Grampus griseus) (n = 11), and common bottlenose dolphin (T. truncatus) (n = 10). Dugongs (Dugong dugon) stranded seven times since 2001. Strandings occurred through-out the year with frequency significantly peaking during the northeast (NE) monsoon (November to March) season. Overall, Regions III (Central Luzon) and VII (Central Visayas) had the highest number of strandings (both n = 27) followed by Regions I (Ilocos) (n = 22) and V (Bicol) (n = 18). The following provinces or local government units were considered hotspots based on high number of strandings observed at each area: Zambales, Cagayan, Zamboanga City, Negros Oriental, Bohol, Pangasinan, and Bataan. Sixty-five percent of all documented stranding events involved live (n = 116) animals. This high percentage might be linked to dynamite fishing (causing acoustic trauma), fish-eries interactions, or biotoxins from harmful algal blooms coupled to their foodweb. These strandings in general validate the diverse marine mammal assemblage in the Philippines and reveal the vari-ous environmental threats with which they deal.
Content may be subject to copyright.
Aquatic Mammals 2010, 36(3), 219-233, DOI 10.1578/AM.36.3.2010.219
The Philippine Marine Mammal Strandings from
1998 to 2009: Animals in the Philippines in Peril?
Lemnuel V. Aragones,
1, 2, 3
Mary Anne A. Roque,
1, 3
Mariel B. Flores,
Richard P. Encomienda,
Gail E. Laule,
Bianca G. Espinos,
Francis E. Maniago,
Gloria C. Diaz,
Edwyn B. Alesna,
and Robert C. Braun
Institute of Environmental Science and Meteorology, University of the Philippines, Diliman,
Quezon City, Philippines 1101; E-mail:
Ocean Adventure, Camayan Wharf, West Ilanin Forest Area, Subic Bay Freeport Zone, Philippines 2222
Natural Sciences Research Institute, University of the Philippines, Diliman, Quezon City, Philippines 1101
Bureau of Fisheries and Aquatic Resources, PCA Building, Quezon Circle, Diliman, Quezon City, Philippines 1101
A well-maintained marine mammal stranding data-
base can be an invaluable tool in understanding
not only strandings but also changes in the marine
environment. This study aimed to examine the fol-
lowing aspects of marine mammal strandings in the
Philippines: species composition, temporal (i.e.,
frequency of stranding per year and seasonality)
and spatial (i.e., frequency of stranding per region
and province) variation, proportions of alive or dead
specimens, and stranding hotspots. In 2008, a sys-
tematic collection of data on strandings, including
out-of-habitat incidents, resulted in an initial 12-year
database—from 1998 to 2009. A total of 178 strand-
ing events were recorded: 163 single, 10 mass, and
5 out-of-habitat strandings, with an average of 15
observed stranding events annually. Twenty-three
of the 28 confirmed species of marine mammals in
the Philippines were recorded to strand, including
first-recorded specimens for the Indo-Pacific bot-
tlenose dolphin (Tursiops aduncus), pygmy sperm
whale (Kogia breviceps), and Longman’s beaked
whale (Indopacetus pacificus). The top five most
frequent species to strand included spinner dol-
phin (Stenella longirostris) (n = 26), short-finned
pilot whale (Globicephala macrorhynchus) (n =
14), melon-headed whale (Peponocephala electra)
(n = 13), Risso’s dolphin (Grampus griseus) (n =
11), and common bottlenose dolphin (T. truncatus)
(n = 10). Dugongs (Dugong dugon) stranded seven
times since 2001. Strandings occurred through-
out the year with frequency significantly peaking
during the northeast (NE) monsoon (November
to March) season. Overall, Regions III (Central
Luzon) and VII (Central Visayas) had the highest
number of strandings (both n = 27) followed by
Regions I (Ilocos) (n = 22) and V (Bicol) (n = 18).
The following provinces or local government units
were considered hotspots based on high number
of strandings observed at each area: Zambales,
Cagayan, Zamboanga City, Negros Oriental, Bohol,
Pangasinan, and Bataan. Sixty-five percent of all
documented stranding events involved live (n =
116) animals. This high percentage might be linked
to dynamite fishing (causing acoustic trauma), fish-
eries interactions, or biotoxins from harmful algal
blooms coupled to their foodweb. These strandings
in general validate the diverse marine mammal
assemblage in the Philippines and reveal the vari-
ous environmental threats with which they deal.
Key Words: marine mammals, stranding, strand-
ing database, stranding network, dolphins, whales,
dugongs, Philippines
A marine mammal stranding is an event in which
an individual or group of marine mammals
washes ashore after death or is found on the beach
or shore in a helpless situation unable to return to
the water on its own ability (Geraci & Lounsbury,
2005). A stranding is categorized either as dead or
alive, depending on the state of the animal when
it was initially observed, and as single or mass. A
mother/calf pair that strand together is considered
a single stranding, while a mass stranding per-
tains to a simultaneous stranding of two or more
animals. Marine mammals are said to be out-of-
habitat when these animals, usually pelagic spe-
cies (e.g., pilot whales, common dolphins), are
found close to shallow waters and likely at risk
of becoming stranded (National Oceanographic
and Atmospheric Administration/National Marine
Fisheries Service [NOAA/NMFS], 2009). Since
these species are often in a large group, others
(Brownell et al., 2009) refer to out-of-habitat as
near mass stranding.
Aragones et al.
A database detailing the records of marine
mammal strandings is a valuable resource for
information regarding species occurrence, distri-
bution, potential abundance, and ocean and human
health since marine mammals are considered
sentinel species (Bossart, 2009). Furthermore, a
decomposing carcass on a beach is still consid-
ered important in certain cases because it can yield
valuable information regarding an individual’s life
history, genetics, predators, contaminants, and
feeding ecology. Live strandings of a rare species
can inform us about that species physiology and
behavior. Every stranding event presents a sci-
entific opportunity to add knowledge and under-
standing regarding a certain aspect of a species
(Perrin & Geraci, 2002).
Strandings occur worldwide. Although global
statistics of these events are lacking, several coun-
tries have established formal stranding response
programs and well-established national databases
(e.g., United States, Australia, United Kingdom,
and Canada). In the United States, a National
Stranding Alert Network for six regional centers
with a central database file was established after
passage of the Marine Mammal Protection Act in
1972, which led to the establishment of the Marine
Mammal Health and Stranding Response Program
(MMHSRP). In Southeast Asia, Vietnam and
Thailand have established their respective national
stranding programs (Perrin & Geraci, 2002). The
oldest stranding program, although not scientifi-
cally based (i.e., not systematically catalogued),
could be in Vietnam where cetacean specimens
that washed ashore were collected and preserved
in the Buddhist temples for centuries (Smith et al.,
1997). In general, however, a national stranding
response program and a stranding database are
often nonexistent in many developing countries,
which often harbor an unknown assemblage of
marine mammal populations.
In the Philippines, it is not surprising to
encounter stranded marine mammals because the
country represents an archipelago of more than
7,100 islands with a total coastline of 36,289 km
(Fajardo, 2001; The Official Government Portal of
the Republic of the Philippines, 2010). Aragones
(2008) reported that 27 species of marine mam-
mals (i.e., 26 cetaceans and one sirenian) were
recorded in Philippine waters, and several
accounts indicated that they strand in various parts
of the country. However, most reporting of marine
mammal strandings in the Philippines has been
sporadic and opportunistic. As such, the informa-
tion regarding these events has not been intention-
ally or systematically collected nationwide.
The Bureau of Fisheries and Aquatic Resources
(BFAR) of the Department of Agriculture has
mandate over marine mammals in the Philippines,
except for the dugong, which is under the
Department of Environment and Natural Resources
(DENR). In October 2005, BFAR, in collabora-
tion with Ocean Adventure (OA), a marine park
located in Subic Bay, established the Philippine
Marine Mammal Stranding Network (PMMSN)
(Aragones et al., 2008).
The main purpose of this study is to examine
the various aspects of marine mammal strandings
from the Philippines. Investigation of the data
that were collected was aimed mainly at the fol-
lowing questions: (1) species composition of the
marine mammals that stranded, (2) temporal vari-
ation (i.e., seasonality), (3) spatial variation (i.e.,
frequency of stranding per year and by region),
(4) proportions of alive or dead specimens, and
(5) potentially identified stranding hotspots. A
stranding hotspot is an area of concern as strand-
ings in this place are often unusually higher than
in other regions (after Bradshaw et al., 2006) and/
or involve endangered or rare species. This infor-
mation could be vital to the identification of loca-
tions for marine mammal rescue centers that might
be established in strategic stranding hotspot areas.
Also, such details could be valuable information
to a conservation plan for the marine mammals in
the Philippines.
This paper highlights some important results
from collation of the details surrounding docu-
mented strandings of marine mammals in the
Philippines from 1998 to 2009. A comprehensive
and systematic stranding database could shed
light on many aspects of marine mammal science
and contribute to information for monitoring the
changes in our marine environment.
Materials and Methods
All available data on marine mammal strandings,
including out-of-habitat events, was collated from
government offices (BFAR, DENR) and selected
local government (LGUs) offices; from nongov-
ernment offices (OA and its nonprofit arm, Wildlife
In Need [WIN]); from the media in the form of
newspaper or online reports (particularly those
in archives); and from the Museum of Natural
History at the University of the Philippines, Los
Baños. Also, data records from actual strandings
that the authors responded to or assisted with were
included in this paper.
Collection of data from BFAR was conducted
primarily by visiting 12 of the 17 regional offices
nationwide (Appendix 1). The Philippines, due
to its archipelagic nature, is divided into 17
regions for administrative purposes. The 17th is
its Central Office (in the National Capital Region
[NCR], Figure 1). The two other regional offices
sent a compilation of their incident reports. The
Philippine Marine Mammal Strandings 1998-2009
stranding data from Region III were collected
mainly by OA and WIN. Since OA and WIN are
located in Region III and have responded to most
stranding events in that region, they were the main
data source for this region. Most of the strandings
that occurred from 2006 to 2009 were directly
reported during the actual stranding events by var-
ious personnel from regional offices and LGUs.
A standard stranding report form for the
PMMSN was completed for each stranding or
out-of-habitat incident (see Appendix 2; after
Aragones & Laule, 2008). The main variables
gathered included, but were not limited to, spe-
cies identification, location, date and time, age
class (calf, subadult, and adult), alive or dead,
rehabilitated or immediately released, or restrand-
ing. A stranded marine mammal is considered for
rehabilitation when it is brought to a facility for
medical attention. Often an animal is stabilized—
that is, it is given supportive care to prevent fur-
ther injury and kept in an upright position protect-
ing the blowhole from water and debris (Geraci &
Lounsbury, 2005). This is performed in the area
where it stranded before it is considered for release
(usually after at least a couple of hours). Other
relevant information, including possible cause
of stranding (e.g., signs of fisheries interaction),
manner of carcass disposal, morphometrics, if tis-
sues or bones were collected and preserved, and if
a necropsy was performed, was also collated.
Very limited data were collected from years
prior to 1998. The regularity of collection of yearly
stranding records began only in 1998. Thus, it was
decided to limit the presented analyses to datasets
ure 1. The 17 Regions of the Philippines (see Appendix 1 for list of
corresponding names of various regions)
Figure 1. The 17 regions of the Philippines (see Appendix 1 for list of corresponding names of various regions)
Aragones et al.
from 1998 to 2009. Stranding events reported
between these years were investigated for dif-
ferences in stranding frequency by year, region,
season, species, sex, age class, dead or alive, and
rehabilitation success.
An ANOVA was used to examine potential sig-
nificant differences in the frequency of stranding
events between seasons across the years. The sea-
sonal scheme was based on the prevailing winds
at certain months of the years: northeast (NE)
monsoon from November to March, southwest
(SW) monsoon from June to September, lull
(or transition) period before SW monsoon – from
April to May, and lull period before NE monsoon
in October (Wang, 2006).
A total of 178 stranding events were recorded from
1998 to 2009, which were comprised of 163 single
and 10 mass stranding events, and five out-of-
habitat incidents (Table 1). The annual frequency
of strandings ranged from two (in 1999 and 2000)
to 48 (in 2009) with an average of 15 events per
year (Figure 2). A total of 222 individuals were
involved in all documented strandings. Single
stranding events involved 163 individuals, includ-
ing three events of mother/calf pairs, while 34 indi-
viduals represented the 10 mass stranding events.
An estimated 370 individuals were involved in the
five out-of-habitat events (including 350 individu-
als for two out-of-habitat events of melon-headed
whales [Peponecephala electra]). Seven species
were observed to mass strand, with three species
mass stranding more than once (Table 1). The
oldest recorded stranding was from 1967, where 12
sperm whales (Physeter macrocephalus) stranded
at Cadiz City, Negros Occidental.
Species Composition and Species Which Strand
Most Frequently
Twenty-three of the 28 confirmed species of
marine mammals found in Philippine waters
(Aragones, 2008; Aragones et al., unpub. data)
were recorded to strand, including first-recorded
specimens for Indo-Pacific bottlenose dolphin
Table 1. Frequency of stranding events and total number of individuals per species
Stranding/out-of-habitat frequency (no. of individuals) Total stranding/out-of-
habitat frequency (no. of
individuals**)Species Single Mass Out-of-habitat
Stenella longirostris
26 26 (26)
Stenella attenuata
5 1 (3) 6 (8)
Stenella coeruloealba
2 1 (2) 3 (4)
Lagenodelphis hosei
8 8 (8)
Tursiops aduncus
7 7 (7)
Tursiops truncatus
7 2 (5) 1 (6) 10 (18)
Steno bredanensis
7 7 (7)
Grampus griseus
9 2 (4) 11 (13)
Orcaella brevirostris
1 1 (1)
Peponocephala electra
10 1 (3) 2 (350) 13 (13)
Globicephala macrorhynchus
14* 14 (15)
Pseudorca crassidens
2 2 (2)
Feresa attenuata
5 2 (14) 7 (19)
Kogia sima
8* 8 (9)
Kogia breviceps
2 2 (2)
Physeter macrocephalus
6 1 (5) 7 (11)
Mesoplodon densirostris
2 2 (2)
Indopacetus pacificus
1 1 (1)
Megaptera novaeangliae
3 3 (3)
Balaenoptera edeni
4 4 (4)
Balaenoptera omurai
2 2 (2)
Balaenoptera spp.
1 1 (1)
Dugong dugon
7 7 (7)
Unknown 24* 2 (14*) 26 (39)
Total 163 (166) 10 (36) 5 (370) 178 (222)
*Involved a mother/calf pair
**Excluding out-of-habitat
Philippine Marine Mammal Strandings 1998-2009
(Tursiops aduncus), pygmy sperm whale (Kogia
breviceps) (Aragones et al., unpub. data), and the
Longman’s beaked whale (Indopacetus pacificus)
(Acebes et al., 2005). From these 23 species, 18
were odontocetes, four were mysticetes, and one
sirenian—the dugong (Dugong dugon). The hump-
back (Megaptera novaeangliae) and the Omura’s
(Balaenoptera omurai) were some of the large
species of whales (mysticetes) to have stranded
in the Philippines. The dugong, the only sirenian
among the recorded stranded marine mammals in
the Philippines, stranded seven times since 2001.
The top five most frequently observed species to
strand include the spinner dolphin (n = 26), short-
finned pilot whale (Globicephala macrorhynchus)
(n = 14), melon-headed whale (n = 13), Risso’s
dolphin (Grampus griseus) (n = 11), and common
bottlenose dolphin (T. truncatus) (n = 10). Most of
the species stranded singly.
Species that were recorded to mass strand
at least twice included the pygmy killer whale
(Feresa attenuata), Risso’s dolphin, and common
bottlenose dolphin. Two out-of-habitat or near
mass strandings of melon-headed whales in
February and March 2009 consisted of at least
150 to 250 individuals for each event (Table 1)
(Aragones et al., unpub. data). There were three
species that stranded only once (n = 1): Irrawaddy
dolphin (Orcaella brevirostris), Longman’s
beaked whale, and an unidentified Balaenoptera
sp. whale. The species identification of 25 strand-
ing events remains unknown. These reports were
from the years 2003 to 2009 and included too little
detail to identify the species.
Seasonality of Strandings
Strandings occurred throughout the year, with fre-
quency of events peaking during the NE monsoon
(November to March) (N = 61; 34%) and dipping
during the lull period before the NE monsoon
(October) (N = 5; 5%) (Figure 3). A significant
difference in seasonality for strandings across
years (p = 0.041) was identified.
Spatial Variation of Strandings and Stranding
Two spatial scales, both based on geopolitical
boundaries—regional and provincial—were used
for management purposes as these are the relevant
political units that will implement respective pro-
grams to address issues, such as stranding, within
their respective boundaries. On a regional basis,
Regions III (Central Luzon) and VII (Central
Visayas) had the highest number of stranding
incidents (both n = 27) followed by Regions I
(Ilocos Region) (n = 22) and V (Bicol Region)
(n = 18) (Figure 4). On a provincial or LGU basis,
strandings were most frequent in the provinces
of Zambales (n = 14), followed by Cagayan (n =
10), Zamboanga City (n = 10), Bohol (n = 10),
Negros Oriental (n = 10), Pangasinan (n = 9), and
Bataan (n = 9) (see Figure 4). Of the three large
island groups in this country, Luzon presented
more strandings (n = 101) than Visayas (n = 43)
and Mindanao (n = 33) combined.
Some locations might be considered hotspots by
virtue of being a site of unusual stranding events.
In one case, Davao City (Region XI) is a hotspot
since this was where the Longman’s beaked
whale stranded in 2004. Similarly, the shoreline
of Bulacan (Region III) in Manila Bay is a hotspot
because this was where the first recorded speci-
men of the pygmy sperm whale in the Philippines
stranded. Similarly, Batangas is a hotspot because
it had the highest number (n = 4) of stranding of
baleen whales (Bryde’s).
Age Class and Gender
Age class was undetermined for about 29%
(n = 64) of all the stranded individuals that were
documented. For individuals for which age class
was determined (n = 158), 61% were adults
n = 96), 25% were subadults (n = 39), 9% were
calves (n = 15), and 5% were strandings of mother/
calf pairs (n = 8). Gender was not determined for
a large proportion (76%, n = 169) of stranded
individuals. When gender was determined, there
was an almost 1:1 ratio (females, n = 23; males,
n = 30).
Figure 2. Annual frequency of strandings from the
Lull (NE)
Lull (SW)
Figure 3. Yearly frequency of strandings during different
monsoon periods in the Philippines
Aragones et al.
Live Stranding
More than half (65%) of the stranding events
(n = 116) involved live animals. Of these 116
live events, 103 involved single individuals, eight
represented mass strandings, and five were out-
of-habitat. As for their disposition, 40% (n = 46)
of the live stranding incidents resulted in death
on site. Of the remaining incidents, 32% (n =
37) of the events involved individuals that were
released immediately, 4% (n = 5) swam back to
the open sea, 1% (n = 1) resulted in death of one
and release of the other individual (from the same
mass stranding), and 23% (n = 27) required reha-
bilitation (Figure 5). The overall survival rate for
rehabilitated individuals was 11% (3 out of 27)
(Figure 6): one was released and the other two
were considered nonreleasable individuals that
are still alive at OA. An adult female short-finned
pilot whale was euthanized.
Diverse Marine Mammal Assemblage of Strandings
in the Philippines
This 12-year stranding dataset revealed many
interesting results regarding marine mammals in
the Philippines. First, it supports the suggested
diverse assemblage of marine mammals in the
Philippines. In one of the earliest works regard-
ing Philippine marine mammals, Leatherwood
Figure 4. Strandings from 1998 to 2009 identified by region. Solid circles
represent frequency of strandings in each region. Hotspot provinces and LGUs
are represented by shaded areas on the map.
Figure 4. Strandings from 1998 to 2009 identified by region; solid circles represent frequency of strandings in each region.
Hotspot provinces and LGUs are represented by shaded areas on the map.
Philippine Marine Mammal Strandings 1998-2009
et al. (1992) reported 17 species found around the
Philippines; three years later, Tan (1995) reported
20 species. Ten years later, Perrin et al. (2005)
removed two species (finless porpoise and pygmy
sperm whale) from Tan’s list because there were
no recently confirmed records of these species. In
2008, 27 species were reported within Philippine
territorial waters (Aragones, 2008). Of these, 23
have been recorded to strand. Recently, the first-
recorded specimen to confirm the presence of the
pygmy sperm whale in the Philippines came from
a stranding in Bulakan, Bulacan area of Manila
Bay (Aragones et al., unpub. data), increasing the
estimated total number of marine mammal spe-
cies in the Philippines from 27 to 28. The second
specimen for this species actually stranded in the
northwestern Luzon (Pasuquin, Ilocos Norte) less
than a month later.* Likewise, the first confirmed
specimen of the Indo-Pacific bottlenose dolphin
in the Philippine waters came from a strand-
ing in Bagac, Bataan, in 2003 (Aragones, 2008).
One of the rarest cetacean species to strand in
the Philippines to date is the Longman’s beaked
whale. A subadult stranded in Davao City (Region
XI) in January 2004 (Acebes et al., 2005).
* For a complete list of strandings in the Philippines from
1998 to 2009, check out
Temporal Variation in Strandings
Examination of temporal variation in strandings
from the Philippines indicated that these events
do vary temporally. Annual increases in stranding
events from 1998 to 2009 might be attributed to a
growing awareness of the general public regarding
the plight of marine mammals in the Philippines,
and the recognition of the need to address and
record stranding events. The first considerable
documented increase in stranding events occurred
in 2005-2006 (Figure 3). This was most likely
an artifact of an increase in people’s awareness
since 2005 was the year the PMMSN was initially
formed. The formation of the PMMSN and the
training of key BFAR personnel regarding marine
mammal stranding response spurred the devel-
opment of local response teams and networks in
various regional offices and greatly contributed
to an increased effort for recording and respond-
ing to these events. The second major spike in
stranding events was observed in 2009 (Figure
3); however, this was most likely an extraordi-
nary year for strandings (n = 48). This elevated
number of events may have been a result of the
increased media hype (both national and interna-
tional) regarding the unusual near mass strand-
ing (300 to 350 individuals) of melon-headed
whales in Bataan on February 10, 2009 (Aragones
et al., unpub. data). The weeklong media cover-
age (and Internet blogging) for this event resulted
in an increased awareness regarding dolphins and
whales nationwide. Whether educated or capti-
vated by such an unusual event, coastal residents
seemed more willing to report stranding events
than in the past. It is also possible that some ille-
gal fishing practice(s) or environmental changes
contributed to such an unusually high incidence of
strandings (see below). Further, it might be likely
that the annual average number of strandings of
15 from 1998 to 2009 represents an underestimate
in events because past incidents might have been
unreported. As systematic collection of data on
strandings continues nationwide, a more accurate
picture of the situation, including unusual interan-
nual variations (or oscillations, such as in 2009),
might be seen.
As for seasonality, an emerging pattern was
that more stranding events occurred during the NE
monsoons (Figure 3). One possible explanation is
that strong upwellings occur or that most upwell-
ings in the Philippines are at their maximum
during the NE monsoons as observed in the north-
western Luzon and eastern Mindanao (Udarbe-
Walker & Villanoy, 2001). More strandings were
recorded in the western section of Luzon than
anywhere else in the entire Philippine archipel-
ago during the NE monsoons. The NE monsoon
winds produce strong alongshore currents which
ure 5. Disposition of the initially live-stranded individuals from the
Philippines (1998-2009).
1 Died, 1
Died Released Out-of-habitat 1 died, 1 released
n = 27
n = 46
n = 37
n = 5
n = 1
Figure 5. Disposition of the initially live-stranded
ure 6. Condition of the animal after rehabilitation
ure 7. Stranding hotspots in the Philippines
Result of rehabilitation
Alive/kept Released Died Euthanized
n = 2
n = 1
n = 23
n = 1
Figure 6. Condition of the animal after rehabilitation
Aragones et al.
flow along the shelf with sharp bends and steep
slope areas producing upwellings (Udarbe-Walker
& Villanoy, 2001; Amedo et al., 2002). This is an
interesting phenomenon that requires more com-
prehensive studies. In the island state of Tasmania
in Australia, increases in zonal and meridional
winds resulting in colder and presumably nutrient-
rich waters running along the southern Australian
land masses served as good predictors of increases
in stranding frequency (Evans et al., 2005).
Spatial Variation of Strandings and Stranding
The spatial variation in stranding events, which
lead to the identification of hotspots, can be attrib-
uted to several factors. The entire NW (Regions I
and III), northern (Region II), and SW (Batangas)
sections of Luzon; the Bicol peninsula; Central
Visayas (Region VII); southern Zamboanga penin-
sula (Region IX); and the Davao area (Region XI)
seem to be major stranding hotspots (Figure 7).
Differences in the frequency of stranding events
in space (i.e., the regional and provincial levels)
could be an artifact of (1) actual marine mammal
distribution, (2) prey availability, (3) intensity of
fishing efforts and propensity of illegal fishing
practice(s), and (4) variation in regional aware-
ness of folks in the coastal communities.
In the initial assessment for marine mammals
in the Philippines, western Luzon, Tañon Strait,
Bohol Sea, Sulu Sea, and Mindanao Sea, which
were some of the identified stranding hotspots,
were also areas of concern for cetaceans. These
waters had more species and high relative
Figure 7. Stranding hotspots in the Philippines
Figure 7. Stranding hotspots in the Philippines
Philippine Marine Mammal Strandings 1998-2009
abundance (Aragones, 2001). Moreover, Tañon
Strait and Sulu Sea, the only bodies of water that
have had comprehensive surveys for cetaceans,
exhibit high densities of several dolphins and
toothed whale species (Dolar et al., 2006).
The results were also consistent with the
known distribution for some species that have
been recorded and studied in the Philippines. For
instance, spinner dolphins were the most frequent
species recorded to strand (Table 2), particu-
larly along the Tañon Strait (between the islands
of Negros and Cebu) and the Bohol Sea, both
in Central Visayas (Region VII), and were also
frequently encountered in these waters during
surveys (Leatherwood et al., 1992; Abrenica
& Calumpong, 2002; Dolar et al., 2003, 2006;
Aragones, 2008; Aragones et al., unpub. data). All
recorded strandings of the humpback whale (n =
3) were in Northern Luzon where sightings have
been reported since 1964 (Slijper et al., 1964). A
stranding of an Irrawaddy dolphin in Dumangas,
Iloilo, in 2006 provided the first evidence that
such species was not restricted to Malampaya
Sound, Palawan. This has significant implications
with respect to the context of how to conserve
and manage this supposedly most endangered
cetacean species in the Philippines (Perrin et al.,
2005). Furthermore, the results validated the wide
distributional range of many marine mammal spe-
cies in the Philippines and suggest the possibil-
ity of multiple populations of some species. The
spinner, Fraser’s, Risso’s, and common bottlenose
dolphins; short-finned pilot whale; and dugong
all stranded at least once in Luzon, Visayas, and
The intensity of fishing efforts and propen-
sity of illegal fishing practices could also help
explain the spatial variation of strandings in the
Philippines. Most of the identified provincial
hotspots, such as Zambales, Bataan, Pangasinan,
Negros Oriental, and Bohol, with the exception
of Zamboanga City (heavily exploited, > 2 to 70
fishers/km), were all included in the very heav-
ily exploited fishing grounds (> 70 fishers/km)
in the Philippines (Tandog-Edralin et al., 1987;
Green et al., 2003). These areas are presumably
fisheries productive waters that can also serve as
marine mammal habitats, particularly for ceta-
ceans. The areas of concern for cetaceans identi-
fied by Aragones (2001), with more species and
high relative abundance, were also reported to
have intensive fishing efforts, resulting in com-
plex marine mammal-fisheries interactions (e.g.,
entanglements). It would not be surprising to
know that many illegal fishing operations occur
within these waters.
Prey availability might have contributed to the
observed spatial variation of stranding events.
Prey availability is known to be enhanced by
upwellings. As mentioned earlier, seasonal upwell-
ings have been recorded in the NW section of
Luzon (Udarbe-Walker & Villanoy, 2001). Most of
the marine mammal hotspot provinces (Zambales,
Bataan, Pangasinan, and Ilocos Norte) are located
in this section (Figure 4). Similarly, strong indica-
tors of upwelling in the northern Bicol shelf were
identified (Amedo et al., 2002); the Bicol region is
also considered a stranding hotspot.
Regional variation in stranding events could
also be attributed to differences in marine
mammal awareness. In Region III, the presence
of OA in Subic, Zambales, and the public educa-
tion messages regarding marine mammals that
OA has imparted could be contributing factors
on why this region has one of the highest number
of reported stranding events. The locals, particu-
larly those from Zambales and Bataan provinces,
often informed OA of stranding incidents, not
only involving marine mammals, but also other
large marine vertebrates, including sea turtles and
sharks. In fact, 24 of the 26 stranding events in
Region III were responded to by OA. In Region V,
the high records could be attributed to the region’s
commitment to responding to stranding events
by creating its own BFAR Region V Stranding
Response Team in 2007.
Live Strandings
The most intriguing result of this study is the
high proportion of live stranded individuals;
65% of total strandings were live. This appears
to be higher than in other countries that maintain
national databases with at least a ten-year data-
set. In Thailand, about 9% of stranded individu-
als were live (K. Adulyanukusol, pers. comm.,
1 January 2010). In Taiwan, 40% of cases from
1990 to 1997 were live strandings (L. S. Chou,
pers. comm., 1 January 2010). In South Australia,
only 11% of the recorded events from 1881 to
2000 were live (Kemper et al., 2005). On the east-
ern coast of the United States, only 17% involved
live strandings (Mead, 1979).
The seemingly high percentage of live strand-
ings observed could be attributed to several
reasons; three hypotheses are discussed. First,
acoustic trauma from dynamite blasts in the
waters where these animals strand is very plau-
sible in the Philippines. Some fishers use timer-
detonated dynamite to stun pelagic fishes in deep
waters during their fishing trips. Allegedly, fish-
ers were using this illegal technique to capture
pelagic fishes found in fish aggregating devices
(FADs). A credible informant, L. Artagame (pers.
comm., 9 November 2009), who happens to be the
Fisherfolk Representative to the National Fisheries
and Aquatic Resources Management Council
Aragones et al.
(NFARMC) and Chairman of the Integrated
Fisheries and Aquatic Resources Management
Council for Region III confirmed that several fish-
ing operators allegedly employed dynamite fishing
offshore Zambales and Bataan provinces the night
before the near mass stranding (out-of-habitat)
event of melon-headed whales in Pilar, Bataan, in
February 2009. In Cagayan, most stranding events
occurred in 2005 to 2007 (Figure 4) when there
had been several reports of dynamite blasting in
the area. These blastings were associated with fish-
ing and treasure hunting for underwater artifacts
from old shipwrecks. After dynamite fishing was
successfully halted by the BFAR Regional office
(Region II) and the Philippine Coast Guard, no
additional cases of strandings have been reported
in that area since 2008. Dynamite fishing in the
Philippines is now known as the infamous scourge
of Philippine seas (Green et al., 2003).
Second, interactions of marine mammals with
fisheries are very possible and might result in
entanglement. Entanglement could weaken the
animals, especially if they have to struggle before
being released. In Peru, high bycatch of small ceta-
ceans from artisanal fisheries has been reported
recently (Mangel et al., 2010). In the UK, 253 of
415 (61%) cetaceans subjected to full veterinary
necropsy from strandings between 1990 and 2006
were determined to have been victims of fisheries
bycatch (Leeney et al., 2008). The Philippines is
one of the world’s largest fish-producing nations,
but its waters are also among the most overfished
as the fishery resource is only 10% of what it
used to be 50 years ago (Green et al., 2003). In
2001, marine fisheries accounted for 57% of the
Philippines’ total fisheries production (Green et al.,
2003). However, as population increases (88.56
million Filipinos as of August 2007; National
Statistics Office [NSO], 2008), fishing efforts
increase as well, resulting in Malthusian fisheries.
Unfortunately, the Philippine archipelago, which
is supposed to be the center of the center of marine
shore fish biodiversity (Carpenter & Springer,
2005), are heavily negatively impacted by all of
these (Green et al., 2003).
The third possible factor for the many live
marine mammal strandings may be associated
with increasing frequency and intensity of harm-
ful algal blooms in the Philippines. Since the first
recorded occurrence of a harmful algal bloom
(HAB) (Pyrodinium bahamense var. compres-
sum) in Manila Bay in 1983 (Bajarias & Relox,
1996; Azanza et al., 2004), many more similar
HAB species (e.g., Cochlodinium polykrikoides,
Noctiluca scintillans, Alexandrium sp.) have
been reported throughout the Philippines (e.g.,
Masinloc, Zambales [Bajarias, 1995]; Western
Palawan [Azanza et al., 2008]; and Cancabato Bay,
Leyte [Marasigan et al., 1995]). In fact, from 1983
to 2002, the Philippines had 40 outbreaks of HABs
in at least 22 coastal areas with subsequent fish
kill and shellfish poisoning episodes (Relox &
Bajarias, 2003). Although detection of algal toxins
in stranded marine mammals has yet to occur in the
Philippines, it is likely that cetaceans are exposed
to biotoxins from HABs through their prey items.
Recently, Leandro et al. (2010) suggested that expo-
sure of the critically endangered North Atlantic
right whales (Eubalaena glacialis) to marine bio-
toxins such as domoic acid is another possible
reason for its failed recovery. Since marine mam-
mals are long-lived and travel significant distances,
they could serve as proxies to detect changes in our
marine environment (Bossart, 2009). Obviously,
a combination of biotoxins, fisheries interactions,
and acoustic trauma could worsen the situation for
these marine mammals.
Special Considerations for the Irrawaddy Dolphin,
the Dugong, and Calves
Stranded animals listed as endangered or rare spe-
cies should be given special considerations during
rescues if for no other reason than their decreased
numbers and the often limited information about
them. In the Philippines, the Irrawaddy dolphin
and the dugong are probably the two most endan-
gered marine mammals (Aragones, 2008); the
former by virtue of a very limited distributional
range (Dolar et al., 2002; Smith et al., 2004; Perrin
et al., 2005), and the latter because of its affiliation
to the coastal areas, particularly seagrass beds,
which is the same zone where human populations
are migrating into, records of direct and indirect
takes occur, and overexploitation is encountered
(Hines et al., in press).
In the case of stranded marine mammal calves,
they require highly specialized, resource intensive,
long-term care. In the event that these animals are
nonreleasable, they still have conservation value
as ambassadors to showcase the plight of their
cousins in the wild when they are exhibited in an
oceanarium, which raises the issue of the avail-
ability of appropriate facilities for the long-term
care of nonreleaseable stranded marine mammals
in the Philippines. Presently, there is only Ocean
Adventure in Subic Bay that has the facilities and
capability to properly care for and maintain reha-
bilitated marine mammals in the Philippines.
Although it has been a remarkable step to collate
stranding data on a national level, more effort and
involvement is needed to record as much data as
possible on every stranding event and develop a
more comprehensive picture of the Philippine
Philippine Marine Mammal Strandings 1998-2009
scenario. Through time, we expect the quality,
accuracy, and completeness of data to improve.
The large proportions of unknown species identi-
fication, age class, and gender in our dataset will
eventually be reduced once people become more
familiar with marine mammals and stranding pro-
tocols. Collections of comprehensive data will
likely lead to greater accuracy in determining the
possible causes of strandings, and the influence of
human activities on these events than our present
dataset. An examination of the possible impacts
of dynamite fishing and other similar underwater
noises resulting in acoustic trauma, marine mam-
mal-fisheries interactions such as bycatch and
entanglements, and possible exposure to biotox-
ins for the Philippine marine mammals should be
more thoroughly investigated.
Marine mammal stranding response capabil-
ity and related facilities should be developed and
improved. The development of regional strand-
ing rescue teams and rehabilitation centers, espe-
cially in the identified hotspots in the Philippines
(see relevant discussion above), could increase
the efficiency of the recording of and success in
responding to strandings. In addition, survival rate
of live-stranded individuals can be increased fur-
ther through a quick response and a well-planned
rehabilitation program. In addition, the need for
an enabling law in the Philippines (with fund
allocation), similar to the U.S. Marine Mammal
Protection Act, providing for National Stranding
Alert Networks and the Marine Mammal Health
and Stranding Response Program (MMHSRP) is
Finally, local and national awareness regarding
marine mammals and strandings must continue to
grow. This can be enhanced by the website of the
PMMSN database, which is now online (www. It is likely that the
majority of strandings still go unreported, but the
more strandings to which we can respond and sys-
tematically collect data, the more we learn about
these individuals, the species, and the status of
marine mammals in the Philippine waters overall.
Funding for this study was provided by the
University of the Philippines (UP)–Diliman
Office of the Vice Chancellor for Research and
Development–Outright Grant to LVA to conduct the
regional visits nationwide, establish the PMMSN
database, and develop its website. Thanks to the
SeaWorld Busch Gardens Conservation Funds
for funding the trainings on marine mammal
stranding response in the Philippines, which led
to the formation of the PMMSN. We are grateful
to the BFAR Director Malcolm Sarmiento and
all Regional Directors for allowing us access to
their data on marine mammal strandings. Thanks
to the UP-Institute of Environmental Science
and Meteorology, Ocean Adventure, Wildlife In
Need, IDESS Maritime Centre, BFAR, and the
Fisheries and Aquatic Resources Management
Councils (FARMCs) throughout the Philippines
for their cooperation. Finally, many thanks to all
those who contributed data and to the volunteers
who responded to stranded marine mammals—
dead or alive. We thank Kathleen Dudzinski and
Ellen Hines for helpful comments to improve the
manuscript. This paper is UP-IESM contribution
number 22.
Literature Cited
Abrenica, B., & Calumpong, H. P. (2002). Whale watching
in Bais City, Negros Oriental, Philippines: An ecotour-
ism enterprise. University of the Philippines Visayas
Journal of Natural Sciences, 7(1&2), 158-168.
Acebes, J. V., Bautista, A., Yamada, T., Dolar, M. L. L., &
Perrin, W. F. (2005, December). Stranding of Indopacetus
pacificus in Davao, Philippines. 16th Biennial Conference
on the Biology of Marine Mammals, San Diego, CA.
[Abstract] (Available at
Amedo, C. L. A., Villanoy, C. L., & Udarbe-Walker, M. J.
(2002). Indicators of upwelling at the Northern Bicol
Shelf. University of the Philippines – Visayas Journal of
Natural Sciences, 7(1&2), 42-52.
Aragones, L.V. (2001). Status and conservation of marine
mammals in the Philippines. Unpublished manu-
script. Final Report submitted to the University of the
Philippines – Los Baños. 78 pp.
Aragones, L. V. (2008). Overview of Philippine marine
mammals. In L. V. Aragones & G. E. Laule (Eds.),
Marine mammal stranding response manual: A guide
for the rescue, rehabilitation, and release of stranded
cetaceans and dugongs in the Philippines (pp. 7-30).
Subic Bay Freeport, Philippines: A Wildlife In Need
(WIN) and Ocean Adventure publication.
Aragones, L. V., & Laule, G. l. (Eds.). (2008). Marine
mammal stranding response manual: A guide for the
rescue, rehabilitation, and release of stranded cetaceans
and dugongs in the Philippines. Subic Bay Freeport,
Philippines: A Wildlife In Need (WIN) and Ocean
Adventure publication.
Aragones, L. V., Alesna, E. B., & Follosco, N. G. (2008).
An introduction to the Philippine Marine Mammal
Stranding Network. In L.V. Aragones & G.E. Laule
(Eds.), Marine mammal stranding response manual:
A guide for the rescue, rehabilitation, and release of
stranded cetaceans and dugongs in the Philippines (pp.
1-2). Subic Bay Freeport, Philippines: A Wildlife In
Need (WIN) and Ocean Adventure publication.
Aragones, L. V., Encomienda, R. P., Flores, M. B., & Roque,
M. A. (2010). [The first and second-recorded specimens
Aragones et al.
for the pygmy sperm whale (Kogia breviceps) in the
Philippines]. Unpublished raw data.
Aragones, L. V., Roque, M. A., Flores, M. B., Encomienda.
R. P., & Desmond, T. (2009). [Unusual near mass
strandings or out of habitat of melon-headed whales
(Peponocephala electra) in Bataan and Romblon].
Unpublished raw data.
Azanza, R. V., David, L. T., Borja, R. T., Baula, I. U., &
Fukuyo, Y. (2008). An extensive Cochlodinium bloom
along the western coast of Palawan, Philippines. Harmful
Algae, 7, 324-330.
Azanza, R. V., Siringan, F. P., San Diego-Mcglone, M. L.,
Yñiquez, A. T., Macalalad, N. H., Zamora, P. B., et al.
(2004). Horizontal dinoflagellate cyst distribution, sedi-
ment characteristics and benthic flux in Manila Bay,
Philippines. Phycological Research, 52, 376-386.
Bajarias, F. F. A. (1995). Dynamics of Pyrodinium red tide
in the coastal waters of Masinloc, Zambales, Philippines.
In P. Wuthisiu & N. Otawa (Eds.), International Seminar
on Marine Fisheries Environment (pp. 139-147).
Rayong, Thailand: EMDEC & JICA.
Bajarias, F. F. A., & Relox, J. R., Jr. (1996). Hydrological and
climatological parameter associated with the Pyrodinium
bloom in Manila Bay, Philippines. In T. Yasumoto, Y.
Oshima, & Y. Fukuyo (Eds.), Harmful and toxic algal
blooms (pp. 49-52). Paris: IOC of UNESCO.
Bossart, G. D. (2009). Marine mammals as sentinels for oceans
and human health. One Health Newsletter, 2(4), 3-6.
Bradshaw, C. J. A., Evans, K., & Hindell, M. A. (2006).
Mass cetacean strandings: A plea for empiri-
cism. Conservation Biology, 20(2), 584-586. doi:
Brownell, R. L., Jr., Ralls, K., Baumann-Pickering, S., &
Poole, M. M. (2009). Behavior of melon-headed whales,
Peponocephala electra, near oceanic islands. Marine
Mammal Science, 25(3), 639-658. doi: 10.1111/j.1748-
Carpenter, K. E., & Springer, V. G. (2005). The center of the
center of marine shore fish biodiversity: The Philippine
Islands. Environmental Biology of Fishes, 72, 467-480.
Dolar, M. L. L., Walker, W. A., Kooyman, G. L., & Perrin,
W. F. (2003). Comparative feeding ecology of spinner
dolphins (Stenella longirostris) and Fraser’s dolphins
(Lagenodelphis hosei) in the Sulu Sea. Marine Mammal
Science, 19(1), 1-19.
Dolar, M. L. L., Perrin, W. F., Gaudiano, J. P., Yaptinchay,
A. A. S. P., & Tan, J. M. L. (2002). Preliminary report
on a small estuarine population of Irrawaddy dolphins
Orcaella brevirostris in the Philippines. The Raffles
Bulletin of Zoology, 10(Supp.), 155-160.
Dolar, M. L. L., Perrin, W. F., Taylor, B. L., Kooyman, G. L.,
& Alava, M. N. R. (2006). Abundance and distributional
ecology of cetaceans in the central Philippines. Journal
of Cetacean Research and Management, 8(1), 93-111.
Evans, K., Thresher, R., Warneke, R. M., Bradshaw,
C. J. A., Pook, M., Thiele, D., et al. (2005). Periodic
variability in cetacean strandings: Links to large-scale
climatic events. Biology Letters, 1, 147-150.
Fajardo, I. S. (2001, August). Surveying and mapping in the
Philippines. Proceedings of the Twentieth International
Cartographic Conference, Beijing, China.
Geraci, J. R., & Lounsbury, V. J. (Eds.). (2005). Marine
mammals ashore: A field guide for strandings (2nd
ed.). College Station: Texas A&M University Sea Grant
College Program.
Green, S. J., White, A. T., Flores, J. O., Carreon III, M. F., &
Sia, A. E. (2003). Philippine fisheries in crisis: A frame-
work for management (CRMP Document No. 03-CRM,
2003). Project of the Department of Environment and
Natural Resources, Cebu City, Philippines.
Hines, E., Aragones, L. V., Adulyanukosol, K.,
Poochaviranon, S., Somany, P., Ath, L. E., Cox, N.,
et al. (In press). Asian dugong. In E. Hines (Ed.),
International strategies for manatee and dugong con-
servation. Gainesville: University Press of Florida.
Kemper, C. M., Flaherty, A., Gibbs, S. E., Hill, M., Long,
M., & Byard, R. W. (2005). Cetacean captures, strand-
ings and mortalities in South Australia 1881-2000, with
special reference to human interactions. Australian
Mammalogy, 27(1), 37-47.
Leandro, L. F., Rolland, R. M., Roth, P. B., Lundholm,
N., Wang, Z., & Doucette, G. J. (2010). Exposure
of the North Atlantic right whale Eubalaena glacia-
lis to the marine algal biotoxin, domoic acid. Marine
Ecological Progress Series, 398, 287-303. doi: 10.3354/
Leatherwood, S., Dolar, L., Wood, C., Aragones, L. V., &
Hill, C. (1992). Marine mammal species confirmed from
Philippines waters. Silliman Journal, 36, 65-86.
Leeney, R. H., Amles, R., Broderick, A. C., Witt, M. J.,
Loveridge, J., Doyle, J., et al. (2008). Spatio-temporal
analysis of cetacean strandings and bycatch in a UK
fisheries hotspot. Biodiversity Conservation, 17, 2323-
2338. doi 10.1007/s10531-008-9377-5
Mangel, J. C., Alfaro-Shigueto, J., Waerebeek, K. V.,
Caceres, C., Bearhop, S., Witt, M. J., et al. (2010). Small
cetacean captures in Peruvian artisanal fisheries: High
despite protective legislation. Biological Conservation,
143, 136-143.
Marasigan, A. N., Ingles, J., & Babaran, R. (1995).
Distribution of resting cysts of Pyrodinium bahamense
var. compressum, Cancabato Bay, Leyte, Philippines. In
P. Wuthisiu & N. Otawa (Eds.), International Seminar on
Marine Fisheries Environment (pp. 149-156). Rayong,
Thailand: EMDEC and JICA.
Mead, J. G. (1979). An analysis of cetacean strandings along
the eastern coast of the United States. In J. R. Geraci
& D. J. St Aubin (Eds.), Biology of marine mammals:
Insights through strandings (pp. 54-68). Washington,
DC: U.S. Marine Mammal Commission.
National Oceanographic and Atmospheric Administration/
National Marine Fisheries Services (NOAA/NMFS)
(2009). NMFS decision process for responding to live
marine mammals that are stranded or otherwise in distress.
Silver Spring, MD: Marine Mammal Health and Stranding
Philippine Marine Mammal Strandings 1998-2009
Response Program. Retrieved 28 June 2010 from www.
National Statistics Office (NSO). (2008). 2007 census of
population of the Philippines. Retrieved 28 June 2010
Perrin, W. F., & Geraci, J. R. (2002). Strandings. In
W. F. Perrin, B. Würsig, & J. G. M. Thewissen (Eds.),
Encyclopedia of marine mammals (pp. 1192-1194).
San Diego: Academic Press.
Perrin, W. F., Reeves, R. R., Dolar, M. L., Jefferson, T. A.,
Marsh, H., Wang, J. Y., et al. (Eds.). (2005). Report of
the Second Workshop on the Biology and Conservation
of Small Cetaceans and Dugongs of Southeast Asia
(CMS Technical Publication No. 9).
Relox, J. R., Jr., & Bajarias, F. F. A. (2003, March).
Harmful algal blooms (HABs) in the Philippines. In
Proceedings of the Workshop on Red Tide Monitoring
in Asian Coastal Waters. Tokyo, Japan: The University
of Tokyo. (Available at
Slijper, E. J., Van Utrecht, W. L., & Naaktgeboren, C.
(1964). Remarks on the distribution and migration of
whales, based on observation from Netherlands ships.
Bijbragen Tot de Djerkunde XXXIV, 34, 3-93.
Smith, B. O., Jefferson, T. A., Leatherwood, S., Ho, D. T.,
Thuoc, C. V., & Quang, L. H. (1997). Investigations of
marine mammals in Vietnam. Asian Marine Biology, 14,
Smith, B. O., Beasley, I., Buccat, M., Calderon, V., Evina,
R., del Valle, J. L., et al. (2004). Status, ecology and
conservation of the Irrawaddy dolphins, Orcaella bre-
virostris in Malampaya Sound, Palawan. Journal for
Cetacean Research and Conservation Management, 6,
Tan, J. L. (1995). A field guide to whales and dolphins in
the Philippines. Makati, Philippines: Bookmark, Inc.
Tandog-Edralin, D. D., Corez-Zaragoza, E. C., Dalzell, P.,
& Pauly, D. (1987). Some aspects of the biology and
population dynamics of skipjacks (Katsuwonus pela-
mis) in Philippine waters. Interactions of Pacific Tuna
Fisheries General Report, 12, 100-111.
The Official Government Portal of the Republic of the
Philippines. (2010). General information. Retrieved 28
June 2010 from
Udarbe-Walker, M. J. B., & Villanoy, C. L. (2001). Structure
of potential upwelling areas in the Philippines. Deep-
Sea Research Part I, 48, 1499-1518.
Wang, B. (Ed.). (2006). The Asian monsoon. Chichester,
UK: Springer-Verlag.
Aragones et al.
Appendix 1. Date of visit to different BFAR regional offices and corresponding names per region
Region Name of region Location of regional office Date of visit
I Ilocos Region San Fernando City, La Union 5 October 2009
II Cagayan Valley Tuguegarao City, Cagayan 21-23 October 2008
III Central Luzon Pampanga and Bulacan Not visited (via telephone)
IVA CALABARZON (Southern Tagalog A) Quezon City, Metro Manila 14-15 July 2009
IVB MIMAROPA (Southern Tagalog B) Calapan City, Oriental Mindoro Through correspondence
V Bicol Region Pili, Camarines Sur 10-14 October 2008
VI Western Visayas Iloilo City Through correspondence
VII Central Visayas Cebu City, Cebu 24-25 August 2009
VIII Eastern Visayas Tacloban City, Leyte 6-8 March 2009
IX Zamboanga Peninsula Zamboanga City 31 July to 1 August 2009
X Northern Mindanao Cagayan de Oro City, Misamis Oriental 4-5 September 2009
XI Davao Region Davao City 21-23 November 2009
XII SOCCSKSARGEN General Santos City, South Cotabato 16-17 November 2009
XIII Caraga Butuan City, Agusan del Norte 8-9 September 2009
CAR Cordillera Autonomous Region
Baguio City, Benguet Not visited
ARMM Autonomous Region of
Muslim Mindanao
Cotabato City, Maguindanao 10-11 November 2009
Philippine Marine Mammal Strandings 1998-2009
Appendix 2. Stranding response report form (after Aragones & Laule, 2008)
Appendix 2. Stranding response report form (after Aragones and Laule, 2008)
... The increasing trend and plateau imply that the continuing high total annual frequencies is beyond the artifact of people being educated about strandings and reporting them but that this sustained strandings must be compounded by other factors. In 2010, the main factors that explained the increasing trends then were: increasing awareness, toxins, and fishing efforts (both legal & illegal;Aragones at al. 2010). The PMMSN through the Marine Mammal Research and Stranding Laboratory of the UP IESM is currently examining the effects of pollution (chemical & noise), diseases, marine debris and by-catch on marine mammal stranding events nationwide, to mention a few. ...
... Moreover, the comprehensive stranding database of the country has been utilized to elucidate the ecology of these animals (Aragones et al. unpublished data). An initial analysis was conducted by Aragones et al. 2010 using the compiled stranding data from 1998 to 2009 examining spatial and temporal trends as well as identifying potential geographical hotspots. More comprehensive analyses of the national stranding database from 2005 to 2016 was conducted by Aragones and his colleagues in 2017. ...
... These specific areas should be the primary or focal areas of interest for the concerned Provincial Fisheries Officers and BFAR Regional Directors in terms of strategic management or planning of trainings and the like. Previous reports (Aragones et al. 2010, Aragones and Laggui 2019 which also focused on regional hotspots practically showed very similar trends. ...
Full-text available
Technical Report
Stranding of marine mammals is complex and understanding this phenomenon requires continuous surveillance, monitoring, data collection and research. The Philippine Marine Mammal Stranding Network (PMMSN) has collected 1178 records of stranding events nationwide from 2005 to 2020. This Technical Report is a follow-up to the second Report (i.e., Aragones and Laggui 2019). As stated in the second Technical Report the consequent series of Reports will cover two-year periods only. Thus, this third Report covers the stranding dataset from 2019 to 2020. However, as in the first (Aragones et al. 2017) and second Reports, updates on the general trends for the larger data set (2005 to 2020) will also be provided. This Report showcases analyses of the stranding records from 2019 to 2020 (n=220) for trends in stranding frequency by year, region, season, monsoon, species, sex, age class, original disposition, release and rehabilitation success. The spatial coverage presented in this report was specific to regions and provinces primarily for administrative purposes. Identification of more specific or smaller spatial areas (i.e., by municipality/city) for potential stranding hotspots was assessed using Fishnet Tools (using 15 x 15 km grids). Furthermore, seasonality of stranding events was categorized according to the prevailing monsoons. The Northeast (NE) monsoon months are November to February (NDJF), Southwest (SW monsoon) monsoon months are June to September (JJAS), and Spring Inter-monsoon (Spring IM) in October (or Lull before NE monsoon) and the Winter Inter-monsoon (Winter IM) from March to May (MAM, or Lull before SW monsoon). The stranding data was also presented in the more classic seasonal context of DJF, MAM, JJA, SON. As data analytics advances, future reports will be improved further.
... The study reports that 33% of the strandings were confirmed to be related to human interaction. Aragones et al. (2010) discussed the causes of cetacean strandings in the Philippines but did not specifically focus on marine debris. Other studies focus on individual species; for example, Baird and Beasley (2005) revealed how bycatch is a threat to the Irrawaddy dolphin (Orcaella brevirostris) population in the Mekong River. ...
... Pages with posts on the same individual were counted as the same data point. Mass strandings (two or more individuals (Aragones et al. 2010)), and the stranding of a mother and calf, were recorded as single stranding events. All information included in the posts was recorded, which included: species (if known and confirmed from the photographic evidence); location; date; cause of death and whether a necropsy was carried out. ...
... For example, the Facebook page 'Philippine Marine Mammal Stranding Network' (PMMSN) was an efficient source of data. The formation of the PMMSN and the training of Bureau of Fisheries and Aquatic Resources (BFAR) personnel on the response to marine mammal strandings led to the development of local response teams which substantially increased effort for recording and responding to stranding events (Aragones et al. 2010). Stranding events related to marine debris in the Philippines were particularly frequent in the Davao region, around Davao City, in agreement with the findings of Abreo et al. (2019). ...
Full-text available
Litter in the marine environment, in particular plastic, is a significant threat to marine megafauna. Cetaceans are known to ingest or become entangled in marine debris, likely impacting individuals and populations. Southeast Asia is a biodiversity hotspot and harbours a diverse cetacean assemblage. However, there are key knowledge gaps relating to the impact of litter in this region due the lack of experts to survey its vast coastlines. This study aims to address such gaps by using social media, gathering data from Facebook posts relating to cetacean strandings and litter across Southeast Asia between 2009 and 2019. Results show that at least 15 cetacean species have been negatively affected by litter, with ingestion most commonly affecting deep-diving species. Epipelagic and mesopelagic foragers were most vulnerable to entanglement. Davao in the Philippines was identified as a litter-related stranding hotspot. The Irrawaddy dolphin ( Orcaella brevirostris ) and pygmy sperm whale ( Kogia breviceps ) are particularly vulnerable to litter. The combination of social media and peer reviewed literature can help build a more complete picture of the spatial distribution of marine litter and the scale of the impact it has on cetacean populations. In this study we provide details of a valuable online tool for helping to understand the impact of marine litter on cetaceans and other charismatic species that are a focus of community engagement.
... Significant historical and current data on seasonal and spatial patterns of occurrence and mortality, diet, age structure, sexual proportion, population genetic variability, diet, interannual variations associated with climatic and / or anthropogenic events, causes of mortality, displacement and other aspects of natural history about marine mammals was acquired through the investigation of stranded animals, because strandings provide exclusive access to species that are evasive (COLEGROVE ; GREIG; GULLAND , 2005;BOGOMOLNI et al., 2010). A well-organized and maintained database of strandings of marine animals can be an invaluable tool in understanding not only bottlenecks, but also changes in the marine environment (ARAGONES et al., 2010). A database that details the records of strandings of marine animals is a valuable resource for collecting information on occurrence, distribution, potential abundance, and human and oceanic health (BOSSART, 2009). ...
... Strandings of marine animals occur all over the world. Although not exist global statistics on such events (ARAGONES et al., 2010), several countries (like the United States, Canada, Brazil, Peru, United Kingdom, Italy, Ireland, Australia, the Philippines, among others) have established formal monitoring programs (SWINGLE et al., 2013;VIANNA et al., 2016). In 1972 was established in the United States a National Register Network of stranding of marine animals, composed of six regional centers, whose data is stored in a central database (ARAGONES et al., 2010;Swingle et al., 2013). ...
... Although not exist global statistics on such events (ARAGONES et al., 2010), several countries (like the United States, Canada, Brazil, Peru, United Kingdom, Italy, Ireland, Australia, the Philippines, among others) have established formal monitoring programs (SWINGLE et al., 2013;VIANNA et al., 2016). In 1972 was established in the United States a National Register Network of stranding of marine animals, composed of six regional centers, whose data is stored in a central database (ARAGONES et al., 2010;Swingle et al., 2013). In 1991, the Rio Grande do Sul Aquatic Mammals Study Group (GEMARS) was founded, a nongovernmental, non-profit organization that aims to develop scientific research and environmental education programs related to conservation of aquatic mammal species, as well as their natural environments. ...
Full-text available
Stranding is the event in which a marine animal comes ashore after death or comes and is unable to return to the sea, which may occur due to natural, spatial tendencies and anthropic actions. It occurs in many countries, several of which have created formal programs to monitor. Mammals are at the top of the food chain, suffering more from changes in the environment, which is why they indicate the quality of the ecosystem. In the southern region of Brazil, inventories of marine mammal biodiversity emerged in the 1980s. Registering stranded data makes it possible to discover important information about marine animals and the oceans. This work aimed to collect information to identify the composition and abundance of strandings of marine mammals. The studied area is located on the southern coast of Santa Catarina, between the municipality of Jaguaruna and Passo de Torres. Data refer to collections made by the Zoology Museum Morgana Cirimbelli Gaidzinski , from the University of the Extreme South of Santa Catarina (UNESC), during the period from 2003 to 2016, through third-party activations and systematic monthly monitoring. The stranding frequency in this period was 344 mammals, belonging to 15 species, 10 genera, six families and two different orders. The occurrence of rare and unpublished animals was observed, such as Balaenoptera physalus, Kogia breviceps and Arctocephalus gazela.
... In this study, swab and tissue samples collected from cetaceans that stranded locally from February 2017-April 2018 were subjected to bacterial isolation (with subsequent antibiotic resistance screening) and histopathological assessment. Data on antibiotic resistant bacteria, parasites, and tissue lesions in cetaceans are valuable in evaluating the factors that may be associated with their local stranding events, observed to have increased in recent years [23,24]. Of the 29 confirmed species in the country, 28 were reported to have stranded from 2005-2018 [24]. ...
... One of the ways to confirm acoustic trauma is through histological observations of the inner ears [56]. Acoustic trauma was suggested as the cause of some previously reported cetacean stranding events in the Philippines, possibly due to blast fishing activities near the stranding sites [23,57]. There is a growing concern on marine environment being compromised by human activities (e.g. ...
Full-text available
The relatively high frequency of marine mammal stranding events in the Philippines provide many research opportunities. A select set of stranders (n = 21) from 2017 to 2018 were sampled for bacteriology and histopathology. Pertinent tissues and bacteria were collected from individuals representing eight cetacean species (i.e. Feresa attenuata, Kogia breviceps, Globicephala macrorhynchus, Grampus griseus, Lagenodelphis hosei, Peponocephala electra, Stenella attenuata and Stenella longirostris) and were subjected to histopathological examination and antibiotic resistance screening, respectively. The antibiotic resistance profiles of 24 bacteria (belonging to genera Escherichia, Enterobacter, Klebsiella, Proteus, and Shigella) that were isolated from four cetaceans were determined using 18 antibiotics. All 24 isolates were resistant to at least one antibiotic class, and 79.17% were classified as multiple antibiotic resistant (MAR). The MAR index values of isolates ranged from 0.06 to 0.39 with all the isolates resistant to erythromycin (100%; n = 24) and susceptible to imipenem, doripenem, ciprofloxacin, chloramphenicol, and gentamicin (100%; n = 24). The resistance profiles of these bacteria show the extent of antimicrobial resistance in the marine environment, and may inform medical management decisions during rehabilitation of stranded cetaceans. Due to inadequate gross descriptions and limited data gathered by the responders during the stranding events, the significance of histopathological lesions in association with disease diagnosis in each cetacean stranding or mortality remained inconclusive; however, these histopathological findings may be indicative or contributory to the resulting debility and stress during their strandings. The findings of the study demonstrate the challenges faced by cetacean species in the wild, such as but not limited to, biological pollution through land-sea movement of effluents, fisheries interactions, and anthropogenic activities.
... Over the past few decades, strandings and bycatch events have occasionally been recorded for sperm whales along the coastal zones of the SCS, including five regions of China, i.e., Hainan (Liu et al., 2019b), Taiwan (Wang, 1991), Hong Kong (Wang, 2012), Guangdong (Zhan et al., 2019), and Fujian (Wang, 2012), and other neighboring countries, such as the Philippines (Aragones et al., 2010) and Singapore (Chua et al., 2019). However, sporadic stranding information is insufficient to represent the actual status of whales in the wild (Liu et al., 2022). ...
Full-text available
Sperm whales (Physeter macrocephalus) are widely distributed in deep waters worldwide, yet relatively little is known about this species in the South China Sea (SCS). Here, an integrated approach was used to investigate sperm whales in this region. First, we compiled records of 28 strandings, two bycatch incidents, and 63 opportunistic sightings of sperm whales in the SCS, and these historical records indicated that sperm whales have occurred occasionally in the SCS. Second, we conducted four ship-based surveys from 2019 to 2021 to investigate cetaceans in the northern SCS. During these surveys, we recorded 130 cetacean sightings, including nine sperm whale sightings, with a group size of 5.1 ± 2.3 individuals (mean ± SD). Of nine sperm whale sightings, seven were determined to be nursery groups, with 1–2 calves/juveniles per group. This finding suggests that the northern SCS might be a nursing ground for sperm whales. Twenty-two individuals were photographically identified from six groups with no resightings, indicating that there are probably more whales within the investigated area that have not been identified. Third, we tagged three adult sperm whales from a nursery group with LIMPET satellite tags on July 24, 2020. Satellite-tracking data showed that these whales occupied a relatively small area (≤2200 km²) within <10 days, with an estimated travel distance of ≤400 km for each individual. To conclude, this is the first study to document the frequent existence and probable residence of sperm whales in the northern SCS. Considering that sperm whales in this area may represent only a small portion of the entire SCS population, additional field surveys and biologging efforts are required to investigate sperm whales in the SCS and help reveal the broad distribution, movement patterns, and habitat preferences of sperm whales in the region.
... in/ nwap_ 2017_ 31). Standard stranding response protocols have proven to increase the efficiency of responding and recording of stranding events 75,76 , and protocols and training guidelines are readily and freely available from global resources (e.g., www. gmast. ...
Full-text available
Marine mammal strandings provide vital information on species’ life histories, population health and status of marine ecosystems. Opportunistic reporting of strandings also serve as a powerful low-cost tool for monitoring these elusive mammals. We collated data over ~ 270 years available through various open access databases, reports and publications. Annual strandings along the Indian coast (mean = 11.25 ± SE 9.1) increased in the last two years of the study (2015–2017, mean = 27.66 ± SE 8.5 strandings /year). We found that stranding events spike during June—September along the west coast and during December–January along the east coast. We identified several sections of the coastline, such as Mumbai (0.38 strandings/km), Kozhikode (0.28 strandings/km), Tuticorin (0.4 strandings/km), Rameswaram (1.82 strandings/km), Chennai (0.32 strandings/km) and Bhubaneshwar (0.26 strandings/km) with a higher number of stranded animals reported. Emerging Hotspot Analysis located new and consecutive hotspots along the north-west coast, and sporadic hotspots along the south-east coast. We recommend establishing regional stranding response centres at the identified hotspots coordinated by a National Stranding Centre with adequately trained personnel and central funding support. Regular stranding response training programs for field veterinarians, and frontline personnel of State Forest Departments near stranding hotspots would provide an improved understanding of marine mammal health and threats in Indian waters. Further, the suggested National Stranding Centre needs to maintain a ‘National Stranding Database’ for long-term marine mammal conservation planning in India.
... Interactions among marine mammals and coastal activities can also be identified from stranding observations and information (Felix et al., 1997;Leeney et al., 2008). Furthermore, in the long term, species-specific spatio-temporal patterns may also be identified (Torres de la Riva et al., 2009;Norman et al., 2004;Evans et al., 2005;Aragones et al., 2010;Truchon et al., 2013). On the other hand, the consequence of the erroneous identification of stranded marine mammals by beach users, whether the animals are confused with other taxa or their species cannot be identified, is that coordination among actors becomes challenging, resulting in wasted human and economic resources within the RMMS. ...
Beach users play a fundamental role in responses to marine mammal strandings (RMMS), as they are usually the first to detect and report strandings. Informed beach users facilitate effective responses, increasing the odds of rescuing live animals and obtaining data on the stranding events. This information allows for the causes of stranding events to be related with climatic, anthropogenic, or oceanographic phenomena. The main objective of this study was to evaluate whether beach users in Bahía Todos Santos are currently capable of acting as first responders and to propose strategies for the dissemination of information regarding RMMS. The results of our surveys highlighted the importance of informing beach users about marine mammals, the actions to take during a stranding event, and the health risks of zoonotic diseases. The actions of a first responder include detecting the stranding, reporting the stranding to authorities and competent actors, and providing key information to the recipients of the report. These actions will help authorities activate the local RMMS network to ensure timely responses. We propose the use of signage on beaches and social media campaigns to disseminate information aimed at informing first responders. Finally, we consider it is important to involve the public in these activities to raise awareness regarding the conservation of marine mammals and their environment.
... These marine mammals can therefore perceive the generated sound from these explosions. Note that Philippine marine mammals include delphinids, ziphiids, and a sirenian, the dugong (Aragones et al. 2010). The average SPL from the explosion is also close to 150 to 160 dB re 1 μPa, the SPL generated by multiple pulse explosions that caused changes in behavioral responses of humpback whales (Todd et al. 1996;Southall et al. 2008). ...
Full-text available
Underwater noise poses serious threats to marine mammals, which rely on underwater sound primarily for communication, orientation, and foraging. In this study, underwater noise from dynamite fishing was analyzed to infer possible effects on local marine mammals, particularly cetaceans. Simulated explosions were performed on 9 July 2018 using confiscated explosives from illegal fishers in San Fernando, La Union. The acoustic properties of blasts from single pulse explosions were characterized using sound recordings captured by a hydrophone. Dominant frequencies from the sound recordings showed that the noise generated by the explosions can be perceived by marine mammals sensitive to the auditory bandwidth of 7 Hz to 180 kHz. Blast charge weights were estimated to determine sound pressure levels generated by the explosions at varying distances from the source. These results imply that marine mammals within 150 m of the explosion will experience debilitating injuries (e.g., acoustic trauma, disorientation) even from a single pulse. By characterizing the acoustic properties of these local explosives, its potential impacts to local marine mammals and other marine organisms can be elucidated. These acoustic calculations can be further enhanced by considering backscattered waves and determining the actual chemical composition of these explosives.
... Strandings are unfortunate events, but we find from this review that these events may provide research opportunities that are otherwise difficult to achieve under normal circumstances. An increasing trend of research based on data collected from stranded specimens has been observed (Aragones et al., 2010), but we find that there is still some wasted opportunity in the use of such specimens and suggest further expanding studies on strandings. We also not that there has been no concerted effort to collate all specimens from strandings -a quandary resulting from a lack of coordination between research institutions, volunteer groups, and BFAR. ...
Full-text available
Global marine mammal research is disproportionately lacking compared to terrestrial mammal research and is strongly biased toward populations in Europe, North America, New Zealand, and Australia. With high extinction risks facing marine mammals in the tropics, we sought to identify potential drivers of research effort and extinction risk evaluations for marine mammals in the Philippines as a model for tropical island nations with limited resources and research capacity. Using a bibliographic approach, we compiled all materials on marine mammal research in the Philippines from 1991 to 2020, which we categorized into eight thematic areas of research focus. We reviewed all materials based on their research focus to assess the current scientific knowledge of local marine mammal populations. Using a simple metric to calculate research effort allocation, we found that all marine mammal species in the Philippines receive inadequate research attention. Using generalized linear models, we analyzed the relationship of potential factors that drive research effort. The model with the lowest Akaike Information Criterion value suggests that frequency of marine mammal stranding incidents may influence an increase in research effort on marine mammals by providing access to biological specimens that would normally be difficult to obtain. Strandings are unfortunate events with often unclear causes, but they provide an opportunity to collect data from behaviorally cryptic animals in areas where financial constraints often hamper scientific progress. We also determined that a national Red List evaluation was predicted by increased research effort. Maximizing local research using all materials from strandings and building research capacity may be an alternative to expensive field-based methods to increase knowledge on local marine mammal populations.
... This process can generate information regarding the species of marine mammals that strand in the Philippines (Aragones et al. 2013). In the long-term, the information generated by recording every stranding event can elucidate the health of our oceans with the marine mammals serving as sentinels (Aragones et al. 2010). The Philippine Marine Mammal Stranding Network (PMMSN) has been gathering and collating recorded stranding data through the Marine Mammal Research and Stranding Laboratory of the University of the Philippines -Institute of Environmental Science and Meteorology. ...
During a survey in 1999 covering the coastal waters of the northwestern Sulu Sea and Malampaya Sound, Palawan, we sighted several groups of Irrawaddy dolphins (Orcaella brevirostris). Distribution was restricted to very shallow waters (≤ 15 m) of the inner part of Malampaya Sound. No Irrawaddy dolphin sightings were made in the Sulu Sea. No directed fisheries exist for the dolphin, but some incidental mortality occurs in fishing gear such as bottom-set gillnets, fish corrals, liftnets and crab traps. The habitat is endangered by encroaching fisheries, terrestrial development and increasing human population around the sound.
Harmful algal blooms are one of the marine environmental problems and resource management issues that confront the Philippines. It has been recognized as a catastrophic phenomenon that affects public health and economy of the country since 1983. Fish mass mortality associated with algal blooms in 2002 have been observed and documented. Fish kills attributed to blooms of Prorocentrum minimum, Cochlodinium polykrikoides and Alexandrium sp occurred in various localities in Luzon Island. Unverified reports of red tide occurrence in eastern side of Luzon Island circulated. The occurrence of red tides brought significant economic loss of around Php100million and the dislocation of fisherfolks. Constraints and limitation of the red tide monitoring system in the Philippines and the possible application of satellite data in the monitoring was presented. Introduction Harmful algal blooms is not a new phenomenon in the Philippines. Since 1908 blooms of Peridinium sp in Manila Bay have been reported. The first recorded occurrence of blooms of Pyrodinium bahamense var. compressum, a toxin-producing dinoflagellate was in 1983 in central Philippines, (Estudillo and Gonzales, 1984) and since it was the first time that the country has experienced such kind of phenomenon, its impact in terms of public health and economy was so great. Apparently, harmful algal blooms in the country, particularly Pyrodinium have expanded both in time and space (Bajarias and Relox, 1996; Corrales and Gomez,1990). Blooms of Pyrodinium spread to around 22 coastal areas of the country. Paralytic shellfish poisoning due to Pyrodinium has increased in severity during the last two decades. The country has experienced more than 40 outbreaks of harmful algal blooms with subsequent shellfish poisoning episodes between 1983 and 2002. However, most of the blooms have not been documented. Narrative of local folks of water discoloration in the remote coastal areas of the country abound. These narratives have not been validated and documented due to the archipelagic nature of the country with more than 7,100 islands and the lack of resources to monitor all the coastal waters. Documented algal blooms in the Philippines with emphasis on blooms that cause fish kills is presented, and also discuss the constraints and/or limitations in monitoring red tides in the country and possibility of application of satellite data for a more efficient and quick red tide monitoring tool.
This study summarizes 660 events involving captured, live-stranded and dead cetaceans in South Australia between 1881 and 2000. Emphasis is placed on records (n = 361) during 1985-2000 when an active necropsy programme was underway. Average number of events per year was 30.4 and the most common species were the short-beaked common dolphin (Delphinus delphis) and Indo-Pacific bottlenose dolphin (Tursiops aduncus). Records were assigned to nine categories of circumstance/cause of death. Summarizing the total database, 60% were unknown circumstance, 22% not obviously anthropogenic, 13% unintentional human-related and 5% intentional human-related. In the data set of records for 1985-2000, 50% were unknown, 25% were not obviously anthropogenic, 20% were unintentional humanrelated and 5% were intentional killings. Non-anthropogenic circumstances included neonatal deaths, live strandings, significant diseases, shark attacks and choking. Cornynebacterium ulcerans is recorded for the first time in a cetacean. Unintentional circumstances included entanglement in fishing and aquaculture equipment (17% of necropsied carcasses from 1985-2000) and boat strikes. Intentional human-related circumstances were captures for live display and illegal killing. Five percent of the necropsied carcasses during 1985-2000 were attributed to shootings or stabbings/spearings. There is need for a formal reporting procedure for marine mammal deaths and human interaction involving injury and for steps to be taken to reduce human impacts.