MASS STRANDING OF PEPONOCEPHALA ELECTRA (CETACEA,GLOBICEPHALINAE) ON PIRACANGA BEACH,BARIA, NORTHEASTERN BRAZIL

LILIANE LODI 1l, SALVATORE SICILIAN02l AND LILIAN CAPISTRAN0 3l
ABSTRACTOn 16 April 1987 a pod of over 240 melon-headed whales, Peponoce phalaelectra (Gray, 1846), stranded on Piracanga Beach, Bahia, northeastern
Brazil (14°14'S, 39°00'W). A total of 182 whales were examined 8 days after
the stranding period had started. Data on body length and/or sex ratio from123 specimens were collected. The group of animals examined included 81
females and 44 males; 57 individuals could not be sexed due to decomposition and damage caused by vulture feeding.
Key words: Peponocephala electra, mass stranding, northeastern Brazil

INTRODUCTION

On 16 April 1987 a group of melon-headed whales, Peponocephala electra, wasobserved stranding on Piracanga Beach (14°14'S, 39°00'W), ltacare County,
approximately 423 km south of Salvador, State of Bahia, Brazil. Because of theremoteness of the stranding site, news of the event took several days to reachthe authors. Although melon-headed whales have a world-wide distribution intropical and subtropical seas (Leatherwood and Reeves, 1983), we here reporton the first known mass stranding of the melon-headed whale, for the AtlanticOcean. This species has only recently been recorded for the Brazilian coast,
based on a skull collected at Caravelas, southern Bahia, in July 1985 (Siciliano,Fiori, Lodi and Borobia, 1987).
THE STRANDING

Piracanga is a 14.5 km sandy beach, with widths varying from 11 and 18.5 m.
Projeto Baleia Jubarte, Convenio IBAMA!NEMA, Parque Nacional Marinho dos Abrolhos
Present address: Rua Conde de Bonfim, 9551504, Rio de Janeiro, RJ 20530, Brazil
2) Projeto Baleia Jubarte, Convenio IBAMA/NEMA, Parque Nacional Marinho dos Abrolhos
Present address: Rua Jose Higino, 3401102, Rio de Janeiro, RJ 20520, Brazil
3) Projeto Cetaceos, C.P. 122-903, Atafona, Sao Joao da Barra, RJ 28150, Brazil
1)

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LODI, SICILIANO AND CAPISTRANO

Two rivers flow into the ocean, the Piracanga and Aibim de Melo, which arelined with mangrove swamps.
For three days preceeding the stranding, winds from the south and southeast with speeds varying between Beaufort scale 1 and 6 were recorded. Suchwinds were coupled with heavy rain and air temperatures averaging 26°C.
During the stranding, the rains continued and winds generally from the south,
varied between Beaufort scale 1 and 3 (National Institute of Meteorology, VIDistrict, Station 83348, Ilheus, Bahia). The stranding occurred during a fullmoon period.
Information on the circumstances of the stranding was obtained from local
fishermen. The whales stranded on the beach in groups, starting on 16 April andcontinuing until 19 April, when the last group came ashore. Local people tried
unsuccessfully to push some of the whales back into the water. Certain individuals arrived bleeding, probably after being injured by the coral reef off Piracanga
Beach. Some females reportedly aborted on the beach, although we found nofoetuses on the beach upon our arrival. The actual number of whales stranded
was probably higher than that reported here since some of them were removed
and consumed by local people. In this case smaller animals were selected as they
were easier to transport. Other whales were observed washing away with thetide. On 23 April we counted 240 whales, however during the period from 24 to27 April, due to continued high tides, we were able to examine only 182 specimens. Most of the carcasses were in a state of advanced decomposition andheavily damaged due to feeding by vultures ( Coragys atratus). Photographs,
data on stomach contents, internal parasites (da Silva, Thatcher and Capistrano,1987), skulls and complete skeletons were collected for further studies.
DISCUSSION

Our findings refer to the second mass stranding of cetaceans reported for theBrazilian coast. On 1 December 1972 a herd of 33 sperm whales, Physetermacrocephalus, stranded on Bojuni Beach, State of Rio Grande do Sul (Castello and Pinero, 1974). Large areas of the Brazilian coast are sparsely inhabited, and interest in reporting and recording strandings is very low. It is only inthe last 10 years that the situation has begun to change as researchers haveincreased their efforts to study marine mammals in Brazil.
During the stranding reported here, whales were found within a 5 kmsection of the beach (Figs 1 and 2). We divided the 5 km stretch of beach into 3
sections for collecting data: section I, the portion of the beach on the south sideof the Piracanga River (46 animals); section II, along the Piracanga River (18animals); and section III, the portion of the beach on the north side of thePiracanga River (118 animals) (Fig. 3).
Of the 125 animals that could be sexed, 81 (64.8%) were females andSci. Rep. Cetacean Res.,
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81PEPONOCEPHALAELECTRA、・制pー"'Fig.1.Strandedmelon‑headedwhaleson PiracangaBeach,April1
987. Photoby
S.SicilianoFig.2. Heado
famelon‑headedw
haleshowingi
tscolorati
onaf
ewd
aysa
fte
rdeathPhotobyS.Siciliano.

ep.CetaceanRes,.
S
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82

KILOMETERS

0'
Aibim de Melo River
83

Piracanga River
20'

S2

S1

ATLANTICOCEANBAHIA40'

SCALE - 1:308541\80'

60°40'

Fig. 3. Map of Piracanga Beach, Bahia State, showing the stranding site and thesections of beach where the melon-headed whales were collected.

16N=123

14D Females

12~Males"':g~ 10c.

0•

Unknown sex

8~

E:Iz

4

100

110

120

130

140

150

160

190

200

210

220

230

240

250

260

270

280

Body langth in cmFig. 4. Body-length frequency distribution for 123 melon-headed whales, Peponocephala electra, mass stranded on Piracanga Beach, Bahia, Brazil.
0Females (n=73),~males (n=42), •unknown sex (n=S).

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PEPONOCEPHALA ELECTRATABLE 1. MASS STRANDINGS OF PEPONOCEPHALA ELECTRA KNOWN TO DATE
Date

Locality

Remarks

Number ofanimals

Reference

April 1987

Piracanga Beach,ltacare, Bahia, Brazil

240+

Present paper

November 1972

Malekoula Is., Vanuatu,
Melanesia

231

Rancurel, 1974

October 1976

Tambor Village,
Costa Rica

180

James G. Mead,pers. comm. 1987

January 1982

Aoshima, Miyazaki
Prefecture, Japan160

Miyazaki, 1983

August 1958

Crowdy Heads,
Australia

Large herd observed off
Port Macquarie a day
before the stranding

150-250

Dawbin et al., 1970

August 1976

Moreton Is.,
Australia

Approx. 300 sighted
near the stranding area

53

Bryden et al., 1977

Approx. 2,000 animals
observed in Ballenas
Bay before the stranding

44(35.2%) were males, for a sex ratio of approximately 2:1. This agrees withresults for a mass stranding of this species on Moreton Island, Australia, where
35 females and 16 males were found (Bryden, Harrison and Lear, 1977) and fora mass stranding in Costa Rica (Pacific coast) where the ratio was approximately two to one (J. Mead, pers. comm., Dec. 1987).
Body-length frequencies were computed based on sexed and/or measured
animals (n = 123) and are shown in Fig. 4. Frequency distribution for both sexes
indicate that a wide range of size classes were involuved in the stranding. The
longest animal, a female, was 275 cm, and the shortest, also a female, 106 cm;
21.4% of the males and 21.9% of the females were between 221 and 230 cm
long. The longest and the shortest males were 261 and 110 cm long, respectively. Females in the Pacific Ocean have been reported to reach sexual
maturity at somewhere between 225 and 257 cm (Bryden et al., 1977), andmales between 248 (Best and Shaughnessy, 1981) and 268 cm (Bryden et al.,1977).
Mass strandings of melon-headed whales have been reported to involvefrom 53 to 250 individuals (Table 1). Sightings (van Bree and Cadenat, 1968;
Dawbin, Roble and Fraser, 1970; Bryden et al., 1977; Miyazaki and Wada, 1978;
Pilleri, 1982) and observations in conjunction with captures (Nishiwaki andNorris, 1966) show that P. electra is highly gregarious and occurs in large
groups.
The reasons for this mass stranding could not be determined.
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LODI, SICILIANO AND CAPISTRANOACKNOWLEDGMENTS

We would like to thank Vera M.F. da Silva and William F. Perrin for reviewing
the manuscript. We also thank Everaldo Lima de Queiroz (Federal Universityof Bahia - UFBA), the former Fisheries Development Agency (SUDEPEBahia branch), the Center of Environmental Studies (CRA), Government ofBahia State and the Prefecture of Itacare for logistical support which made thefield work at Piracanga possible.
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VAN BREE, P.J.H. and CADENAT, J. 1968. On a skull of Peponocephala electra (Gray, 1846) (Cetacea,Globicephalinae) from Senegal. Beaufortia. 14: 193-202
BRYDEN, M.M., HARRISON, R.J. and LEAR, R.J. 1977. Some aspects of the biology of the biology of
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CASTELLO, H.P. and PINERO, M. E. 1974. Varamientos de cachalotes, Physeter catodon, en las costas de!
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S1c1uANO, S., FIORI, B., LoDI, L.F. and BoROBIA, M. 1987. Recent records of small cetaceans from the northeastern and southeastern coasts of Brazil. Abstract of the paper presented to the Seventh Biennial
Conf. on the Biology of Marine Mammals. Miami, 5 - 9 December 1987, 64pp.
DASILVA, V.M.F., THATCHER, V.E. and CAPISTRANO, L. 1987. The mass stranding of Peponocephala electraon the Brazilian coast and the possible relationship to the parasites Stenurus globicephalae (Nematoda)
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