310
12.3 Cetacean Strandings
In Costa Rica cetacean stranding information is available since 1996. Between 1966
and 1999 a total of 35 stranding events (244 individuals) were recorded. These
strandings included predominantly single animals from 13 species of the families
Delphinidae, Kogiidae, Physeteridae and Balaenopteridae (Table 12.1) (RodríguezFonseca and Cubero-Pardo 2001). In addition, in 1976 a stranding of 200 individual
melon headed whales (Peponocephala electra) (~80 died) was reported at Tambor
Beach at Cobano, Peninsula of Nicoya in Puntarenas province. During these 33
years, the causes of death in the stranded animals were not determined (Janzen and
Wilson 1983). Between 2000 and 2016, 96 stranding events involving 98 individuals were described largely by trained scientists. Most of these strandings (97.9%)
consisted of single animals belonging to 16 species within the families Delphinidae,
Kogiidae, Physeteridae, Ziphiidae and Balaenopteridae (see Table 12.1). In 2002,
another mass stranding was reported at Cedros Beach, 24 kilometers apart from the
site of the earlier mass stranding at Tambor Beach in 1976. This time 37 individuals
(4 died) of rough-toothed dolphins stranded (Loaiza 2002).
In Costa Rica systematic postmortem examinations started to be performed in
2001, first by the Pathology Department of the School of Veterinary Medicine of the
National University of Costa Rica; and later on (after 2009) by the National
Veterinary Service of the Ministry of Livestock and Agriculture of the country.
Currently, histopathological analyses are routinely performed for each stranding
including tissue sections from all organs using standard procedures as described by
Kiernan (2003). Since 2001 a total of 70 animal necropsies have been performed in
11 species of odontocetes including, striped dolphins, pantropical spotted dolphins,
spinner dolphins, common dolphins, rough-toothed dolphins, bottlenose dolphins,
Risso’s dolphins, dwarf sperm whale and Cuvier’s beaked whale (Ziphius cavirostris). All these strandings occurred in the Pacific coasta, to this day only two necropsies have been performed in animals stranded in the Caribbean coast, including one
specimen of beaked whale belonging to the genus Mesoplodon and one sperm
whale. By far the most common stranded species was the striped dolphin that represented 72% of all the specimens analyzed during this period of time. The main
cause of death in this species was neurobrucellosis associated with infection caused
by Brucella ceti (Table 12.2).
Causes of death varied among stranded animals and among species. There is
variation in the presence of gastrointestinal parasites, parasitic pneumonias, and
skin lesions. For instance, about 32% of stranded striped dolphins presented a localized unilateral or bilateral ulcerative lesion at the level of the mandibular condyle,
directly below the eye or slightly frontal or caudal, irregular to oval in shape and
with variable levels of chronicity. Some animals presented deep ulcerative lesion
with active borders and secondary infection with different species of Vibrio, in the
other hand other animals presented with completely healed wounds with prominent
scar tissue (see figure). Histopathology revealed moderate to severe chronic ulcerative granulomatous dermatitis, negative for special stains intended to demonstrate
L.J. May-Collado et al.
12.3 Cetacean Strandings
In Costa Rica cetacean stranding information is available since 1996. Between 1966
and 1999 a total of 35 stranding events (244 individuals) were recorded. These
strandings included predominantly single animals from 13 species of the families
Delphinidae, Kogiidae, Physeteridae and Balaenopteridae (Table 12.1) (RodríguezFonseca and Cubero-Pardo 2001). In addition, in 1976 a stranding of 200 individual
melon headed whales (Peponocephala electra) (~80 died) was reported at Tambor
Beach at Cobano, Peninsula of Nicoya in Puntarenas province. During these 33
years, the causes of death in the stranded animals were not determined (Janzen and
Wilson 1983). Between 2000 and 2016, 96 stranding events involving 98 individuals were described largely by trained scientists. Most of these strandings (97.9%)
consisted of single animals belonging to 16 species within the families Delphinidae,
Kogiidae, Physeteridae, Ziphiidae and Balaenopteridae (see Table 12.1). In 2002,
another mass stranding was reported at Cedros Beach, 24 kilometers apart from the
site of the earlier mass stranding at Tambor Beach in 1976. This time 37 individuals
(4 died) of rough-toothed dolphins stranded (Loaiza 2002).
In Costa Rica systematic postmortem examinations started to be performed in
2001, first by the Pathology Department of the School of Veterinary Medicine of the
National University of Costa Rica; and later on (after 2009) by the National
Veterinary Service of the Ministry of Livestock and Agriculture of the country.
Currently, histopathological analyses are routinely performed for each stranding
including tissue sections from all organs using standard procedures as described by
Kiernan (2003). Since 2001 a total of 70 animal necropsies have been performed in
11 species of odontocetes including, striped dolphins, pantropical spotted dolphins,
spinner dolphins, common dolphins, rough-toothed dolphins, bottlenose dolphins,
Risso’s dolphins, dwarf sperm whale and Cuvier’s beaked whale (Ziphius cavirostris). All these strandings occurred in the Pacific coasta, to this day only two necropsies have been performed in animals stranded in the Caribbean coast, including one
specimen of beaked whale belonging to the genus Mesoplodon and one sperm
whale. By far the most common stranded species was the striped dolphin that represented 72% of all the specimens analyzed during this period of time. The main
cause of death in this species was neurobrucellosis associated with infection caused
by Brucella ceti (Table 12.2).
Causes of death varied among stranded animals and among species. There is
variation in the presence of gastrointestinal parasites, parasitic pneumonias, and
skin lesions. For instance, about 32% of stranded striped dolphins presented a localized unilateral or bilateral ulcerative lesion at the level of the mandibular condyle,
directly below the eye or slightly frontal or caudal, irregular to oval in shape and
with variable levels of chronicity. Some animals presented deep ulcerative lesion
with active borders and secondary infection with different species of Vibrio, in the
other hand other animals presented with completely healed wounds with prominent
scar tissue (see figure). Histopathology revealed moderate to severe chronic ulcerative granulomatous dermatitis, negative for special stains intended to demonstrate
L.J. May-Collado et al.