Sperm whales off Peru during IMARPE surveys (1995-2002)
Instituto del Mar del Perú (IMARPE)

Dataset credit

Instituto del Mar del Perú (IMARPE)

Contacts

RoleNameOrganization 
Primary contact Ignacio García-Godos Instituto del Mar del Perú
Data entry Ei Fujioka Duke University

Citation

Abstract

Thirty-eight sightings of sperm whales (Physeter macrocephalus) were recorded off Peru (3 degrees S - 18 degrees S) during 21 surveys conducted aboard platforms of opportunity between 1995 and 2002, with a search effort of 33,406.6 nautical miles of observation. Two main areas of concentration were detected: northern Peru (19 sightings) and southern Peru (16 sightings), but seasonality could not be confirmed. Almost 58% of sightings occurred during the same or consecutive days. Group size ranged from 1 to 18 individuals, with a mean of 3.5 individuals (SD = 3.9). The modal group size was one, with single whales accounting for 36.8% of sightings. Groups of three or more individuals accounted for 39.5%. An important increase of sightings occurred between 2001 and 2002, accounting 68% of the records, suggesting migratory movements towards Peruvian waters from other regions of the eastern Pacific Ocean.
Positive correlations between indices of relative abundance and the anomaly of sea surface temperature were found, although warm events as El Niño appear to increase the uncertainty in sighting rates, reducing correlation values. Positive relationship between indices of relative abundance and fishery's CPUE of Dosidicus gigas suggest some grade of interaction, although the question about the role of D. gigas in the diet of sperm whales in the area must be solved for further conclusions. It is priority to perform specific surveys for population estimation, as well as non-lethal research about feeding and the effect of the fishery competition over sperm whales.

Purpose

To show the general pattern of distribution of sperm whales off Peru, a previously important whaling ground.

Supplemental information

N/A

References

García-Godos, I. 2006. A note on the occurrence of sperm whales (Physeter macrocephallus) off Peru, 1995-2002. Journal of Cetacean Research and Management. 8(1):113-119.

Attributes

Overview

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downlodable online. Other attributes may be obtained upon provider's permission unless otherwise noted below.

Attributes in dataset provided

Attribute (table column)Description
dateDate of observation
longLongitude of observation
latLatitude of observation
obs_countNumber of animals observed
speciesSpecies observed
tsnSpecies ITIS TSN
surveycode
vesselR/V Humboldt & R/V Olaya
oidUnique ID number (generated by SEAMAP)
OBIS-SEAMAP ID386
Seabirds0
Marine mammals38
Sea turtles0
Rays and sharks0
Other species0
Non spatial0
Non species0
Total38
Date, Begin1995-12-19
Date, End2002-11-09
Temporal prec.111000
Latitude-18.05 - -3.74
Longitude-84.06 - -71.45
Coord. prec.6 decimal digits
PlatformBoat
Data typeAnimal sighting
EffortN/A
Registered2007-03-01
Updated2007-06-14
StatusPublished
Sharing policy CC-BY-NC (Minimum)
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