First records of the pantropical spotted dolphin &lt;i&gt;Stenella attenuata&lt;/i&gt;, within groups of common dolphins &lt;i&gt;Delphinus delphis&lt;/i&gt; in northern Peru

Lara Martínez,Belén Alcorta,Sebastián Silva,Aldo S Pacheco

doi:10.22370/rbmo.2021.56.1.2801

First records of the pantropical spotted dolphin <i>Stenella attenuata</i>, within groups of common dolphins <i>Delphinus delphis</i> in northern Peru

Lara Martínez, Belén Alcorta + Show 2 more

Open Access

https://doi.org/10.22370/rbmo.2021.56.1.2801

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Abstract

Although dolphins are mostly known to form single species groups of varying size, occasionally they aggregate in mixed-species groups. The presence of mixed-species delphinid groups along the Peruvian coast is unknown. Herein, we report the presence of a single pantropical spotted dolphin (Stenella attenuata) within large groups of the common dolphin (Delphinus delphis) at Los Organos in the northern coast of Peru. Sightings occurred on October 10th, 2016, January 7th, 2018 and September 21st, 2019. In one sighting the mixed group was feeding, while during the other two sightings the group was travelling. These records add new evidence about mixed-species delphinid groups in coastal waters of Peru.

Highlights

The pantropical spotted dolphin Stenella attenuata (Gray, 1846) is a medium sized dolphin of dark grey dorsal coloration with light grey ventral color
The distribution of the neritic form ranges from Mexico to northern Peru
Sightings of pantropical spotted dolphins within common dolphins groups occurred during whale-watching excursions off the coast of Los Organos (04°20’08”S; 81°27’21”W) (Fig. 1), during the humpback whale (Megaptera novaeangliae) breeding season from 15th July to the 30th October

Summary

Introduction

The pantropical spotted dolphin Stenella attenuata (Gray, 1846) is a medium sized dolphin of dark grey dorsal coloration with light grey ventral color. Bearzi (2005) summarized a large data-set of associations and interactions among delphinids, indicating that pantropical spotted dolphins have been observed in mixed species groups with spinner dolphins (Stenella longirostris), common bottlenose dolphins (Tursiops truncatus), dusky dolphins (Lagenorhynchus obscurus), and short-finned pilot whales (Globicephala macrorhynchus). The presence of pantropical spotted dolphins within groups of common dolphins is reported for the first time in waters off Peru.

Materials and methods

Results and discussion

80 Martínez et al Mixed dolphin groups off Peru

Literature cited