Main Solomon Islands IMMA

Criterion A – Species or Population Vulnerability

A study by Bass (2010), based on interviews, showed that dugongs occur throughout the Solomon Islands. Dugong are classified as Vulnerable on the IUCN Red List. Dugong status in the Solomon Islands is poorly known, however a recent questionnaire survey suggests a high rate of bycatch, with 40% of fishermen declaring the by-catch of one dugong in the last five years (Pilcher et al. 2016). Furthermore, 51% of interviewees claimed to know dugong hunters.

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Photo-identification data collected over three consecutive years show strong support for the presence of several small and resident populations in the IMMA. Oremus et al. (2013) conducted small boat surveys (n = 62) in the Solomon Islands in November 2009, November 2010 and July 2011. Total research effort was 5196 km in coastal waters of Guadalcanal, Florida Islands, Santa Isabel and Malaita. Photographs were obtained from 44 groups of T. aduncus and 225 unique individuals were identified. Twenty individuals were re-sighted within the same year while 46 individuals were re-sighted between different years. All re-sightings but one (Florida Islands to Guadalcanal) were found within study sites, indicating a high degree of site fidelity and suggesting a demographic partitioning between the study sites. Therefore, the four islands or group of islands appear to shelter distinct populations, most likely isolated demographically from each other.  Abundance was estimated to be approximately 100 in Guadalcanal and in Florida Islands and around 300 individuals in Santa Isabel.  Abundance estimates for the west coast of Malaita were considered to be less reliable because of insufficient data, however, population size in this area is probably also in the low 100s.

Sub-criterion B2: Aggregations

Shimada and Pastene (1995) described an area of high density for Bryde’s whales in the north the IMMA from a research trip in the Solomon sea in the 1990s. Eight whales presumed to be Bryde’s were also taken in scientific hunting in the late 1970s (Oshumi 1978). Later, Wada (2003) presented evidence that these presumed Bryde’s whales were in fact a distinct species of Balenoptera which he described as Omura’s whales (Balenoptera omurai). Furthermore, Oremus et al. (2013) observed unidentified baleen whales (Balenoptera sp.) very close to shore at each of their four study sites (Guadalcanal, Santa Isabel, Florida Islands and Malaita), involving feeding behavior on one occasion. Although the Balenoptera species was not conclusively identified, total estimated length (ranging from 6 to 10m), and photographs of the rostrum and back of the animals suggest that they were Omura’s whales.

Criterion D: Special Attributes  

Sub-criterion D2: Diversity

So far 21 species of marine mammal species have been documented in the IMMA, indicating an area of rich species diversity (Shimada and Pastene 1995, Kahn 2004, Oremus et al. 2014).