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Documenting marine mammal strandings provides important information needed to understand the occurrence and distribution patterns of species. Here, we report on strandings of cetaceans on the Pacific ( n = 11) and Caribbean ( n = 2) coasts of Nicaragua, documented opportunistically from 2014 to 2021. Strandings included three species of baleen whale (blue whale Balaenoptera musculus , Bryde’s whale Balaenoptera edeni , humpback whale Megaptera novaeangliae ) and five species of toothed whale (dwarf sperm whale Kogia sima , Guiana dolphin Sotalia guianensis , pantropical spotted dolphin Stenella attenuata , spinner dolphin Stenella longirostris , Cuvier’s beaked whale Ziphius cavirostris ). These are the first published accounts of blue whales, Bryde’s whales, dwarf sperm whales, and Cuvier’s beaked whales in Nicaraguan waters. Limited resources and the advanced decomposition of animals prevented necropsies in most cases, the identification of the causes of mortality in all cases, and the species identification of two dolphins. Information derived from these stranding events offers new insights into the occurrence of marine mammals on the Pacific and Caribbean coasts of Nicaragua and Central America.
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M A R I N E R E C O R D Open Access
Cetacean strandings along the Pacific and
Caribbean coasts of Nicaragua from 2014
to 2021
Joëlle De Weerdt
1,2*
, Eric Angel Ramos
3
, Etienne Pouplard
1
, Marc Kochzius
2
and Phillip Clapham
4
Abstract
Documenting marine mammal strandings provides important information needed to understand the occurrence
and distribution patterns of species. Here, we report on strandings of cetaceans on the Pacific (n=11) and
Caribbean (n=2) coasts of Nicaragua, documented opportunistically from 2014 to 2021. Strandings included three
species of baleen whale (blue whale Balaenoptera musculus, Brydes whale Balaenoptera edeni, humpback whale
Megaptera novaeangliae) and five species of toothed whale (dwarf sperm whale Kogia sima, Guiana dolphin Sotalia
guianensis, pantropical spotted dolphin Stenella attenuata, spinner dolphin Stenella longirostris, Cuviers beaked
whale Ziphius cavirostris). These are the first published accounts of blue whales, Brydes whales, dwarf sperm whales,
and Cuviers beaked whales in Nicaraguan waters. Limited resources and the advanced decomposition of animals
prevented necropsies in most cases, the identification of the causes of mortality in all cases, and the species
identification of two dolphins. Information derived from these stranding events offers new insights into the
occurrence of marine mammals on the Pacific and Caribbean coasts of Nicaragua and Central America.
Keywords: Central America, Cetaceans, Citizen science, Diversity, Eastern Tropical Pacific
Introduction
Assessments of the occurrence, distribution, and popula-
tion status of whales and dolphins typically require logis-
tically complex and costly methods such as systematic
boat-based transects and aerial surveys. Implementing
these methods in regions with limited resources is often
infeasible. Data derived from stranding events, while typ-
ically restricted to mortality events along coasts, can
help to document the presence of different cetacean spe-
cies in under-studied areas (Peltier et al. 2012). Strand-
ing events offer opportunities to gather information on
live or dead animals and generate valuable insights on
the presence, diversity, and possible sources of mortality
of local species (Geraci and Lounsbury, 2005; Moura
et al. 2016). Cetaceans strand for a variety of reasons
(both natural and anthropogenic) including poor health
from infectious diseases (e.g., parasites, viruses, bacteria)
and old age; injury caused by boat collisions or entangle-
ment in fishing gear; and (potentially) behavioral and
physiological impacts from pollution (e.g., chemical,
sound) (Reynolds et al. 2009). If conditions and re-
sources allow, data derived from necropsies can reveal
causes of death and help to identify the population ori-
gin of stranded animals (Pyenson 2011).
The occurrence and distribution of cetaceans in some
parts of the Pacific coast of Central America is poorly
understood. The lack of basic information on species
present in Nicaraguan waters limits the development of
effective management practices for cetacean conserva-
tion. Recent findings on recurrent feeding of humpback
whales (De Weerdt and Ramos, 2019) and the presence
of whales from distinct subpopulation (De Weerdt et al.
2020) highlights the need for more in-depth studies on
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* Correspondence: eliscientific@gmail.com
1
Association ELI-S, Education, Liberté, Indépendance - Scientifique, Allée de
Verdalle 39, 33470 Gujan-Mestras, France
2
Marine Biology, Ecology and Biodiversity, Vrije Universiteit Brussel (VUB),
Pleinlaan 2, 1050 Brussel, Belgium
Full list of author information is available at the end of the article
Weerdt et al. Marine Biodiversity Records (2021) 14:13
https://doi.org/10.1186/s41200-021-00209-5
whales and dolphins in the regions. Information on these
species in Nicaragua and Central America is lacking be-
cause of the limited amount of boat-based surveys, the
absence of a coordinated stranding response, and of or-
ganizations trained and equipped to collect standard
stranding data and conduct post-mortem analysis of
stranded animals. Knowledge derived from strandings,
notably cause of death, can help to highlight factors
underlying mortality and serious injury. While the cap-
ture, killing, and harvesting of dolphins (and marine tur-
tles) are prohibited in Nicaragua (Law 489 Art. 77,
Fisheries and Aquaculture), the lack of baseline informa-
tion on species limits the effectiveness of any monitoring,
and the lack of law enforcement and regulation limits
marine megafauna protection. Additionally, Nicaragua has
extensive coastlines on its Pacific and Caribbean coasts
that are logistically challenging to monitor.
Here, we report strandings of cetaceans along the Pa-
cific and Caribbean coasts of Nicaragua observed from
2014 to 2021. We briefly describe what is known about
the occurrence of each species in Central America and
provide information on each stranding event, including
location, date, and state of decomposition.
Methods
The Nicaraguan Pacific coast is composed of a series of
sandy beaches and bays, and includes continental slopes
extending over 100 km from the coast. Data on marine
mammal strandings in the northern and southern Pacific
region of Nicaragua and from the Carribean coast were
collected between 2016 and 2021 by Association ELI-S.
Data was sourced from both a citizen science observa-
tional network involving fishermen and local communi-
ties, and from publications encountered through online
searches and/or on social media. Association ELI-S con-
ducted basic necropsies when strandings occurred in the
research areas located in both the Natural Reserve of
Padre Ramos in the north and San Juan del Sur in the
south of Nicaragua (Fig. 1). Stranding records were in-
cluded only when the date, time and detailed location in-
formation were provided, and when photographic and/or
video evidence was available to allow species identifica-
tion. The state of stranded animals was evaluated based
on pictures/videos, and codes were assigned according to
Geraci and Lounsbury (2005): Code 1: Alive; Code 2:
Fresh carcass; Code 3: Moderate decomposition; Code 4:
Advanced decomposition and Code 5: Mummified or
skeletal remains. On two occasions measurements and
gross necropsies were performed when the stranding was
managed by a member of Association ELI-S; these strand-
ings involved Stenella attenuata and S. longirostris. Linear
length measurements were made from the tip of the
rostrum to the medial notch of the caudal fin (tail).
Results and discussion
A total of 13 strandings involving 16 animals were
documented during the study period 20142021.
This included 11 stranding events on the Pacific
coast and two on the Caribbean coast. Details are
given below.
Fig. 1 Locations of cetacean strandings documented along the Caribbean and Pacific coasts of Nicaragua documented from 2014 to 2021.
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 2 of 9
Guiana dolphin (Sotalia guianensis)
Guiana dolphins are known to occur along the Carib-
bean coastal areas from Southern Brazil to Honduras (da
Silva and Best 1996, Secchi et al. 2018). This species has
been reported as abundant in the 1990s off the Nicar-
aguan coast (Carr and Bonde 2000) and present year-
round in certain areas (Edwards and Schnell 2001). Con-
cerns were raised in these studies regarding the local ex-
tinction of the species due to increasing bycatch in
coastal gillnets. The conservation status of this species is
listed as Near Threatenedon the IUCN Red List (Sec-
chi et al. 2018).
Three adult individuals stranded dead but in good
condition (Code 2) on 8 September 2020 along the
northern Caribbean coast of Nicaragua within the sandy
beach of Bilwi, Puerto Cabezas (Table 1; Fig. 2). There
was insufficient information to determine cause of
death.
Pantropical spotted dolphin (Stenella attenuata)
Pantropical spotted dolphins from the Eastern Tropical
Pacific (ETP) belong to two subspecies based on mor-
phological and genetic analysis: Stenella attenuata
attenuata (offshore form; two stocks) and S. a. graffma-
nii (coastal form) (Leslie & Morin 2016; Perrin 1994).
This species is listed as Least Concernon the IUCN
Red List (Kiszka & Braulik 2018). Spinner dolphins and
pantropical spotted dolphins were reported in the ETP
and in Central American waters through sighting and
stranding data (Cabrera et al. 2014, De Weerdt et al.
2017; Oliveira et al. 2011; Perrin & Gilpatrick 1994;
Rodriguez & Cubero 2001).
Two pantropical spotted dolphins (unknown subspe-
cies) were found stranded. One individual live stranded
on Playa Veracruz de Acayo, along the Pacific coast on
the 23 February 2016 (Table 1; Fig. 2). The animal was
released from a 200-lb long line while in the water and
washed up onto coral reefs after being cut free. It was
kept in a tidal pool by locals but died that same morn-
ing. A necropsy was not performed on this animal, and
besides the evidence for entanglement-related injuries,
there was insufficient data to determine cause of death.
Another individual stranded on Playa Marsella in
southern Nicaragua on 26 September 2019, in good ex-
ternal condition with an inflated tongue (Code 3), and a
body length of approximately 2 m (Table 1; Fig. 2).
Spinner dolphin (Stenella longirostris)
Spinner dolphins are listed as Least Concernon the
IUCN Red List (Braulik & Reeves 2018). They are widely
distributed in tropical waters (Perrin 2009) and occur in
the ETP, both in coastal areas and offshore (Perrin &
Gilpatrick 1994). The ETP pelagic subspecies favours
tropical surface waters, which are characterised by rela-
tively small annual variations in surface temperature and
by a shallow mixed layer (Perrin 2009).
A single adult spinner dolphin was found stranded on
05 April 2017 and deceased in Padre Ramos along the
northern Pacific coast of Nicaragua (Table 1; Fig. 2). The
lack of decomposition of the carcass (Code 2) suggests it
had died recently. The body was measured in the field
Table 1 Summary of reported stranding events in Nicaragua. = Dead; Unk. = Unknown; F = Female. Population status according
to the International Union for the Conservation of Nature (IUCN) status: LC = Least Concern; EN = Endangered; DD = Data Deficient;
VU = Vulnerable. Codes according to Geraci and Lounsbury (2005)
Species Case Number Code Decomposition Code Stranding date Location IUCN status Sex Necropsy
Odontoceti
Kogia sima 1 Alive 1 27 Apr 2017 Pacific DD UK No
Kogia sima 22 05 Dec 2020 Caribbean DD F Yes
Sotalia guianensis 32 08 Sep 2020 Caribbean NT UK No
Stenella attenuata 4 Alive 1 23 Feb 2016 Pacific LC UK No
Stenella attenuata 53 28 Sep 2019 Pacific LC F No
Stenella longirostris 62 05 Apr 2017 Pacific LC F Yes
Unidentified dolphin 7 4 20 Feb 2017 Pacific LC UK No
Unidentified dolphin 8 4 14 Feb 2021 Pacific LC UK No
Ziphius cavirostris 9 Alive 1 23 July 2020 Pacific LC UK No
Mysticeti
Balaenoptera musculus 10 Alive 1 17 Nov 2014 Pacific EN UK No
Balaenoptera edeni 11 2 23 Nov 2020 Pacific VU UK No
Megaptera novaeangliae 12 3 08 Sep 2017 Pacific LC UK No
Megaptera novaeangliae 13 3 17 July 2019 Pacific LC F No
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 3 of 9
and was 150 cm long from snout to fluke; examinations
of its surface revealed no lesions, wounds, or signs of a
possible cause of death. The stomach contained some
leftovers parts from fish, but the animal had apparently
not eaten recently, as evidenced by the absence of un-
digested fish.
Unidentified delphinid
Two dolphins were reported along the northern Pacific
coast on 20 February 2017 in Padre Ramos, and 14 Feb-
ruary 2021 in Jiquilillo, and were both in an advanced
stage of decomposition (Code 4) preventing species
identification (Table 1; Fig. 2). Both individuals were
long-snouted delphinid with small teeth, indicating it
could have been either Stenella longirostris or Delphinus
capensis.
Dwarf sperm whale (Kogia sima)
The two extant species of Kogia spp., pygmy sperm
whale K. breviceps and dwarf sperm whale K. sima in-
habit tropical and temperate waters globally. Both spe-
cies are listed as Data Deficienton the IUCN Red List
(Taylor et al. 2012). The lack of data on both species
reflects their deep-water ecology. They dive for long pe-
riods of time, travel alone or in small groups, and avoid
vessels (Willis & Baird 1998). Dwarf sperm whales have
a slight preference for the continental shelf and slope, as
deduced from the stomach contents of stranded individ-
uals (Caldwell and Caldwell, 1989).
On 26 April 2017, an adult dwarf sperm whale live-
stranded (Code 1) in the Natural Reserve of Padre Ra-
mos on the northern Pacific coast (Table 1; Fig. 3) and
died after a rescue attempt by local fishermen. Videos
and pictures of the animal allowed for confirmation of
species identification based on the presence of the tri-
angular dorsal fin placed midway along the back, to-
gether with the shape of head (Willis & Baird 1998). No
body measurements were taken of the animal. No phys-
ical damage was detected on the individual prior to the
rescue attempt. Sightings of Kogia spp. along the Pacific
Coast of Central America are rare. In the ETP, there is
one published report of a mother-calf pair interacting
with tuna purse-seine fisheries (Scott & Cordaro 1987).
K. sima strandings have been previously reported in
Guatemala (Cabrera et al. 2014) and Costa Rica (Oliveira
et al. 2011) but not along the Pacific coast of Nicaragua.
Fig. 2 Images of four species of cetaceans found stranded along the Pacific and Caribbean coast of Nicaragua from 2014 to 2021. Case 3: Sotalia
guianensis (photo credit : Bilwi community); Case 45: Stenella attenuata (photo credit: Arry Buddha / Celeste Quintana Facebook); Case 6: Stenella
longirostris (photo credit : Etienne Pouplard); Case 78: unidentified delphinid (photo credit : Etienne Pouplard / George Bevan)
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 4 of 9
On 5 December 2020, an adult female dwarf sperm
whale stranded dead (Code 2) in the Caribbean, on Corn
island (Table 1; Fig. 3). The presence of a young fetus
confirmed pregnancy. Adult size was visually estimated
by locals to be about 3 m. Local communities consumed
the animal.
Cuviers beaked whale (Ziphius cavirostris)
Cuviers beaked whales are listed as Least Concernon
the IUCN Red List and are widely distributed in deep (>
200 m) offshore waters (Baird et al. 2020). This species
is sensitive to acoustic disturbance (e.g., seismic disturb-
ance and naval sonar) which can cause behavioral
changes such as habitat displacement (Southall et al.
2016), and sometimes strandings (Simonis et al. 2020).
Cuviers beaked whales have been sighted in Guatemala
during boat-based surveys (Cabrera et al. 2014). One
stranding was reported in Costa Rica (Rodriguez &
Cubero 2001), and three strandings occurred in El Salva-
dor (Bachara et al20).
On the 23 July 2020 a single Cuviers beaked whale live
stranded (Code 1) at 10:40 on Miramar beach, Leon,
along the Pacific coast (Table 1; Fig. 3). Large scrape
marks were observed, presumably made by contact with
coral reefs, and the animal appeared to be stunned.
Local community members forcefully hit the animal in
attempts to make it regain consciousness. The animal
safely swim away from the beach. Videos and photos
allowed species identification.
Blue whale (Balaenoptera musculus)
Blue whales are listed as Endangeredon the IUCN Red
List (Cooke 2018). Individuals from the Southern
Hemisphere have complex movement patterns, and their
distribution remains unclear (Branch et al. 2007). In the
ETP, blue whale occurrence is related to the major
oceanographic complex known as the Costa Rica Dome
(CRD; Reilly & Thayer 1990; Wade & Friedrichsen
1979). Prior to this stranding, the closest observation of
a blue whale (a mother-calf pair) to Nicaragua was made
230 km offshore in September 2003 (Pitman et al. 2007).
An adult blue whale (Code 1) live-stranded on a beach
in Nicaragua in November 2014 (Table 1; Fig. 4). The
individual died after a rescue attempt by local communi-
ties. No body measurements were taken from the animal
and there was insufficient data to identify the cause of
death.
The annual movement pattern of the CRD brings
nutrient-rich waters closer to Central American coastal
waters in November (Fiedler 2002). Satellite tracking
data showed that one tagged blue whale migrated to-
wards the CRD for feeding, leaving California in Septem-
ber and moving along the Mexican coastline (Mate et al.
1999). The geographical proximity of the CRD to
Nicaragua potentially explains the presence of the
stranded blue whale there. Strandings of blue whales
from the ETP are rare (Branch et al. 2007), probably due
to the speciestypically offshore distribution in this
region.
Brydes whale (Balaenoptera edeni)
Brydes whales are listed as Least Concernby the
IUCN and are generally found offshore even if some in-
shore populations or forms exist within the species (the
overall taxonomy of this group remains partly unre-
solved, Cooke & Brownell 2018). Little information is
Fig. 3 Images of two species of cetaceans found stranded along the Pacific and Caribbean coast of Nicaragua from 2014 to 2021, Case 12:
Adult Kogia sima and foetus (photo credit: Eddy Aluvin / George Bevan). Case 9: Adult Ziphius caviorostris (photo credit: Christian Shane)
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 5 of 9
available on this speciesecology in Central America. A
stranded Brydes whales, but usually exhibit offshore dis-
tribution patterns (Quintana-Rizzo 2017). In Oaxaca,
Southern Mexico, four observations were made within
coastal areas (Villegas-Zurita 2016). One stranding event
of a 14 m-long female was documented in 1999 in Playa
Bandera, Costa Rica (Rodriguez & Cubero 2001) and an-
other was in Guatemala (Cabrera et al. 2014).
On 23 November 2020, a juvenile Brydes whale of
about 4 m in length was found dead (Code 2) in Las
Peñitas, León (Table 1; Fig. 4). Species identification was
confirmed with the presence of the dark left jaw, and the
three ridges on the rostrum. At about 4 m, the animal
would have been no older than a yearling. According to
local fishermen it was hit by a boat, but this could not
be inferred from the pictures collected in the field. The
individual was eaten by local communities.
Humpback whale (Megaptera novaeangliae)
Two humpback whale populations migrate into the
coastal Pacific waters of Nicaragua during their breeding
season: the Central American population from the
Northern Hemisphere (Calambokidis 2008), and the
population classified by the International Whaling Com-
mission as G-Stockfrom the Southern Hemisphere
(De Weerdt et al. 2020). Although humpback whales are
listed as Least Concernby the IUCN (Cooke 2018),
the status of the Central American population has been
classified as Threatenedby the National Oceanic and
Atmospheric Administration (NOAA); NOAA recog-
nizes Central American humpback whales as a Distinct
Population Segmentthat requires special attention for
future management actions (Bettridge et al. 2015).
Two humpback whale strandings were reported at two
different sites: one adult in the Natural Reserve of Padre
Ramos (northern Nicaragua) in September 2017 (Code
3), and one juvenile/subadult along the coast of San Juan
del Sur, southern Nicaragua in July 2019 (Code 3)
(Table 1; Fig. 4). Images of the young individual revealed
the presence of linear scars on its flank. No body mea-
surements were taken of either animal, but measure-
ments of the skeleton of the young individual showed
the length to be 10 m. Based on the stranding dates of
these animals and their overlap with the humpback
whales migratory season (September and July, Table 1),
both whales were likely part of the G-Stock Southern
Hemisphere population. Animals from this population
migrate north from Antarctic waters along the coast of
South America in the austral winter, and sometimes
reach Nicaragua (De Weerdt et al. 2020).
Stranded humpback whales have been reported in
neighbouring Guatemala (Cabrera et al. 2014) and Costa
Fig. 4 Images of three species of cetaceans found stranded along the Pacific coast of Nicaragua from 2014 to 2021, Case 10: adult Balaenoptera
musculus (photo credit : website); Case 11: juvenile Balaenoptera edeni (photo credit : website); Case 12 adult Megaptera novaeangliae (photo
credit : Eddy Aluvin); Case 13 juvenile M. novaeangliae) (photo credit : Damaris Obando)
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 6 of 9
Rica (Rodriguez & Cubero 2001; Oliveira et al. 2011) but
limited information prevent determination of population
of origin. Two dead humpback whale calves were re-
ported floating along the Pacific Coast of El Salvador
(23 km off Costa de Sol and 28 km off Playa La Zunga-
nera) in August 2019 (Baires J., personal communica-
tion). Because of the absence of postmortem
examination, it was not possible to determine whether
linear scars found on the stranded juvenile reported here
were acquired pre- or post-mortem. The coastal distri-
bution of humpback whales coincides with areas of high
anthropogenic activity, making them vulnerable to fish-
ing gear entanglements (Reeves et al. 2003).
Conclusions
Here we report the stranding of sixteen individual ani-
mals of seven different species along the Pacific and
Caribbean coasts of Nicaragua. To the best of our know-
ledge, these include the first documented cases of a blue
whale, Brydes whale, Cuviers beaked whale, and dwarf
sperm whale in Nicaraguan waters. Out of the seven
stranded species we identified in Nicaragua, all species
with the exception of the blue whale have stranded in
Guatemala (Cabrera et al. 2014) and in Costa Rica
(Rodriguez & Cubero 2001) and five stranding events
occurred within protected areas (cf. Natural Reserve of
Padre Ramos on the northern Pacific coast). Decompos-
ition state varied between strandings, and the cause of
strandings could not be clearly identified for any speci-
men due to the lack of necropsies. Necropsies should be
used in future monitoring to provide additional data
and, where possible, to determine the cause of death.
This information is crucial especially for species and
small populations with high conservation priority.
Natural diseases can be the cause of strandings for cet-
acean species, as observed in Costa Rica, where cases of
brucellosis were reported in different dolphin species
(Oliveira et al. 2011). Visual detection of diseases is often
difficult, making it hard to determine whether disease
contributed to a stranding event in absence of a nec-
ropsy. In addition to natural causes, anthropogenic activ-
ities can be the ultimate cause of stranding events; these
can include boat collisions, fisheries bycatch, and also
(potentially) chemical and sound pollution (Reynolds
et al. 2009). While boat collisions and bycatch are some-
times obvious even in an external examination, other an-
thropogenic activities are difficult to identify externally
without necropsy, such as chemical and sound pollution
and the acoustic effect of underwater detonation (Reyn-
olds et al. 2009).
The presence of the longline observed with one pan-
tropical spotted dolphin suggests that fisheries can have
an impact on animals in these waters. Humpback whale
entanglement in fishing lines were observed in 2018 in
Padre Ramos and in 2021 in San Juan del Sur (Pers.
Obs.), and illegal trawling activities in southern Nicar-
aguan coastal areas were observed in 2018 in proximity
to a mother-calf pair humpback whale near the strand-
ing location (Pers. Obs.). The illegal use of home-made
bombs as a fishing technique along most Nicaraguan
shorelines (except for the Department of Rivas) could
potentially pose an additional threat to marine mam-
mals. No formal studies exist on the impact of these spe-
cific explosive devices on acoustic or other behaviour,
but studies on seal bombs used in purse-seine fisheries
suggest a potential impact on, and potentially physical
damage to cetaceans (Baumann-Pickering et al. 2015).
Recommendations for future work in this region in-
clude coastal surveys for strandings, obtaining detailed
information on stranded animals from improved necrop-
sies, the collection and analysis of tissue samples to as-
sess health and diseases, and assessment for possible
influences of human interactions on stranded animals.
Cetacean strandings potentially involve risk for
humans. People attempting to render assistance to
stranded animals are at risk of injury and possibly even
death if the animals thrash, and disease can be transmit-
ted from contact with tissue or bodily fluids. In addition,
the consumption of animals by local communities is
concerning for a variety of reasons. These animals carry
diseases that are potentially transmissible to humans
through contact or ingestion. Trace elements, heavy
metals and pesticides are specific contaminants found in
marine mammals that can potentially impact human
health. Regulations governing strandings should be
established to mitigate these threats to human health.
Abbreviations
CRD: Costa Rica Dome; DPS: Distinct Population Segment; ETP: Eastern
Tropical Pacific; IUCN: International Union for Conservation of Nature;
NOAA: National Oceanic and Atmospheric Administration
Acknowledgements
We thank Eddy Francisco Maradiaga Alduvin for centralising the information
of the strandings obtained from the fishermen of the Natural Reserve of
Padre Ramos and submitted to Association ELI-S. Special thanks to the local
community of San Juan del Sur (Damaris Obando, Arry Buddha, Team Alaska,
Angela Volvo) that has been very reactive in sharing stranding data and
being on site. Dive Nicaragua for sharing the measurements of the
humpback whale skeleton. Thanks to George Bevan for the information on
the stranded Kogia sima in Corn Island. Thanks to Christian Shane for sharing
his experience and observation on the Cuvier's beaked whale. Thanks to
Dave Anderson and Robin Baird for help with species identification of Kogia
sima, Jose Baires for sharing his observations on humpback whales in El
Salvador and James Mead for the unidentified dolphin. Thanks to the Bilwy
community for sharing their observation on Sotalia guianensis. Thanks to
Tamara Desfontaines and Emily Cunningham for proofreading.
Authors' contributions
JDW and EPO collected the data from the field and from various sources.
JDW, EAR, PC and MK produced the manuscript. All authors approved the
final manuscript.
Weerdt et al. Marine Biodiversity Records (2021) 14:13 Page 7 of 9
Funding
This research was not funded.
Declarations
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Association ELI-S, Education, Liberté, Indépendance - Scientifique, Allée de
Verdalle 39, 33470 Gujan-Mestras, France.
2
Marine Biology, Ecology and
Biodiversity, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussel, Belgium.
3
Fundación Internacional para la Naturaleza y la Sustentabilidad, Calle Larún
Manzana 75, 75014 Andara, Chetumal, Quintana Roo, Mexico.
4
Seastar
Scientific, 27605 Hake Road SW, 98070 Vashon, WA, USA.
Received: 24 June 2020 Accepted: 10 May 2021
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... The adult dwarf sperm whale was a pregnant female with a fetus of less than 15 cm and still accompanied by a calf, suggesting that females of this species can give birth in consecutive years. The recorded fetus was in an early stage of development, similar to the fetus recorded in Nicaragua in December 2020 [32]. Fetuses from a later stage of development have been recorded in Colombia (~48 cm length) and Honduras (~65 cm length) during March and June, respectively [52,56]. ...
... The estimated length at birth for this species is about 3.4-4 m [28], suggesting that the recorded calf was a very young individual, likely born at the start of the summer. However, contrary to other baleen whales species, births of Bryde's whale are known to occur throughout the year [32,61,62]. In Nicaragua, for example, a 4 m calf stranded in December 2020 [32]. ...
... However, contrary to other baleen whales species, births of Bryde's whale are known to occur throughout the year [32,61,62]. In Nicaragua, for example, a 4 m calf stranded in December 2020 [32]. ...
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To date, few studies have focused on the Bryde's whale, Balaenoptera edeni, one of the eigth species comprising the family Balaenopteridae. This species can be distinguished from other rorquals by the presence of three parallel longitudinal ridges on top of the rostrum, whereas other rorquals possess only one. The potential distribution of this species in the Mexican Pacific is thought to extend south from 26° N, along the coast of Mexico from Baja California to the border with Guatemala. Our knowledge about this species in the Mexican South Pacific is limited, particularly off the coast of Oaxaca where no previous sightings have been reported. The sightings were recorded during oceanic trips to monitor humpback whale (Megaptera novaeangliae) migrations off the central coast of Oaxaca, Mexico, between December 2011 and January 2012. The observation platforms were 6 m fiberglass boats with a 60 hp outboard engine. The geographical coordinates were registered with a handheld GPS; also recorded were sea surface temperature and the behavior of rorqual specimens. The initial species identification was based on the presence of three parallel longitudinal ridges on the head, and was subsequently corroborated by comparing the photographs and video taken during the sightings with field guides. Four separate rorqual sightings were documented between 1.3 and 7.1 km from the coast of Estacahuite, Zipolite, and Ventanilla, Oaxaca, Mexico. Two sightings involved groups with calves; during one sighting, three killer whales, Orcinus orca, were also observed, although neither predatory behavior nor other interaction occurred. The behaviors observed included breaches by calves, surface activity, and slow and erratic movements with sudden changes of direction in response to the presence of the research boat. During surface exhalations, one individual produced vocalizations that were audible at the surface. The presence of B. edeni off the central coast of Oaxaca, Mexico, may be associated with the oceanographic characteristics and high productivity of the Gulf of Tehuantepec. All behaviors observed during the sightings were typical of the species, including evasive maneuvers and sudden changes of direction with respect to the boat. The fortuitous recording of audible vocalizations clearly recognizable from the research boat during surface exhalations is remarkable. These sightings are the first reports of B. edeni for the state of Oaxaca and the Mexican South Pacific. Thus, there is a clear need to increase intensive, long-term monitoring efforts in order to better understand the ecological implications and other aspects related to the presence of the Bryde's whale and other marine mammals in the region. Future research should focus on assessing the spatial and temporal occurrence of B. edeni in this region.