2012. Review of Significant Trade - Cites

Tursiops aduncus
Life history information for T. aduncus is limited (Wang and Yang, 2009) and data mainly
come from study sites in Australia and Japan (Reeves and Brownell, 2009). Age at sexual
maturity typically ranges from 10-15 years, varying between sexes and populations (Wang
and Yang, 2009). The inter-birth interval for T. aduncus is commonly between 3-6 years, with
a maximum lifespan estimated at about 40 years (Wang and Yang, 2009).
The diet of T. aduncus varies geographically, but throughout most of the species’ distribution
consists of benthic and reef-dwelling fish and cephalopods of continental shelf waters
(Ross, 1977; Ross, 1984 cited in Wang and Yang, 2009).
Taxonomic note: T. aduncus was recognised as a distinct species by CITES at CoP13 in
October 2004 (CoP13 Doc. 9.3.1) based on Wang et al. (1999); the distinction between
T. aduncus and T. truncatus was made on the basis of differences in external morphology,
genetics and osteology between reproductively isolated sympatric forms of the western
North Pacific (Wang et al., 1999; 2000a; 2000b).
C. Country review
SOLOMON ISLANDS
Distribution in range State: Globally, T. aduncus has a discontinuous distribution in the
warm temperate to tropical Indo-Pacific, from South Africa in the west, the Indian Ocean to
Southern Japan and northern Australia, as well as oceanic islands distant from land masses
within the range (Hammond et al., 2008; Brownell and Reeves, 2008).
The Solomon Islands has an Exclusive Economic Zone area of 1.37 million sq km, of which
26 000 sq km is part of a continental shelf area (WRI, 2000). Published information on the
species’ distribution, population structure, past catches and population numbers in the
Solomon Islands appears to be lacking. Distinguishing T. aduncus from the common
bottlenose dolphin T. truncatus has presented a challenge in accurately establishing
distribution records for the species, although T. truncatus has not been confirmed in nearshore
waters of the Solomon Islands (Reeves and Horokou, 2008). Limited survey data
(Kahn, 2006; Defran cited in Reeves and Brownell, 2009) suggest that the species’
distribution within inshore waters of the Solomon Islands is patchy, and it is not abundant,
which is consistent with observations in other locations.
A large scale marine assessment covering the western provinces of the Solomon Islands in
2004 surveyed cetaceans for 160 hours by visual and acoustic methods, with 67 hours
dedicated to coastal habitats considered to be preferable by T. aduncus (Kahn, 2006). In this
rapid assessment covering 1228 nautical miles (2089 km), one group of T. aduncus was
sighted off Noro Passage, near Gizo, off the north-western coast of New Georgia Island
(Kahn, 2006; Kahn pers. comm. to Reeves, October 2008 cited in Reeves and Brownell, 2009).
Unpublished data by R. H. Defran was summarised by Reeves and Brownell (2009). Defran
conducted 35 photo-identification surveys of T. aduncus in 2005, 2007 and 2008 across the
entire north coast of Guadalcanal (east and west of Honiara) covering 160 km, the deep
waters between Guadalcanal and the Florida Islands, the northern and southern borders of
the Florida Islands and around Savo Island, as well as “long range” surveys of the extreme
east of Guadalcanal and shores of Marau (Reeves and Brownell, 2009). Defran recorded
some individuals travelling 113 km from Marau to Honiara over a 10 day period, suggesting
their home range may encompass most of the northern Guadalcanal coastline (Reeves and
Brownell, 2009. Defran reported that all but one sighting of T. aduncus had been 500-750 m
offshore and in shallow water (40-50 m deep) (Reeves and Brownell, 2009).
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