Cara E. Miller

Management of Antarctic baleen whales amid past exploitation, current threats and complex marine ecosystems

Abstract As baleen whales recover from severe exploitation, they are probably subject to a wide variety of threats within the Antarctic marine ecosystem, including directed take. Here we review both the management and current status of Antarctic baleen whales and consider those threats likely to impact on them. Threats range from global problems - marine pollution and climate change - to localized issues including shipping, habitat disturbance, unregulated wildlife tourism and fishery activities. We identify the most pressing anthropogenic threats to baleen whales including scientific whaling and climate change. It is unclear whether current management approaches will be able to effectively encompass all these threats while also accounting both for the differing levels of scientific understanding and for the differing recovery rates of the whale species. For management we recommend the following: 1) incorporation of both ecosystem considerations and the suite of identified threats not limited to direct take, 2) identification of measurable indicators of changes in whales that allow more certainty in monitoring of populations and the environment, and 3) recognition of significant relationships between baleen whales and habitat features to provide information on distribution and use.

Indo-Pacific bottlenose dolphin ( Tursiops aduncus ) habitat preference in a heterogeneous, urban, coastal environment

BackgroundLimited information is available regarding the habitat preference of the Indo-Pacific bottlenose dolphin (Tursiops aduncus) in South Australian estuarine environments. The need to overcome this paucity of information is crucial for management and conservation initiatives. This preliminary study investigates the space-time patterns of habitat preference by the Indo-Pacific bottlenose dolphin in the Port Adelaide River-Barker Inlet estuary, a South Australian, urbanised, coastal environment. More specifically, the study aim was to identify a potential preference between bare sand substrate and seagrass beds, the two habitat types present in this environment, through the resighting frequency of recognisable individual dolphins.ResultsPhoto-identification surveys covering the 118 km2 sanctuary area were conducted over 2 survey periods May to August 2006 and from March 2009 to February 2010. Sighting frequency of recognisable individual Indo-Pacific bottlenose dolphins established a significant preference for the bare sand habitat. More specifically, 72 and 18% of the individuals sighted at least on two occasions were observed in the bare sand and seagrass habitats respectively. This trend was consistently observed at both seasonal and annual scales, suggesting a consistency in the distinct use of these two habitats.ConclusionsIt is anticipated that these results will benefit the further development of management and conservation strategies.

Site fidelity and behaviour of spinner dolphins (Stenella longirostris) in Moon reef, Fiji Islands: implications for conservation

Spinner dolphins (Stenella longirostris) were observed to frequent a tropical reef complex off the coast of Fiji on a regular basis. Boats from surrounding tourist destinations visit this reef on a nearly daily basis to observe the dolphins and partake in various tourist activities, such as snorkelling. The aim of the study was to determine whether this reef is a resting habitat for this population. Specifically, we objectively and quantitatively investigated whether spinner dolphins were primarily resting whilst present within the reef and also assessed whether the same individuals revisited the reef over time. Photo-identification techniques and boat based observations were conducted over two study periods (September 2009 and May 2010). Fifty-six recognizable individuals were identified during this period, with 70% resighted on 2 or more occasions. Resting was identified as the most consistent behaviour dolphins engaged in whilst present inside the reef. These preliminary results provide vital information which can be used as a tool in the development and implementation of conservation initiatives as well as providing a basis for future studies investigating the habitat characteristics of this reef.

Discovery of an important aggregation area for endangered scalloped hammerhead sharks, Sphyrna lewini, in the Rewa River estuary, Fiji Islands

The scalloped hammerhead shark, Sphyrna lewini, is endangered throughout its global distribution. Management and protection of this species is challenging in many locations because of limited scientific data and the vulnerable life-history traits of the species. Our study investigated anecdotal evidence that the Rewa River estuary in Fiji serves as an important nursery area for this shark. Research findings indicated that the average length of both males (60.6 ± 6.78 cm, n = 31) and females (60.4 ± 6.85 cm, n = 51) was well within published size limits of juvenile S. lewini studied in other locations (range = 38.0–89.5 cm). On the basis of published reference points for umbilical scar status we postulate that the first captured juveniles were born in January of the study year. Stomach content analysis found the following prey items: Decapoda (represented by prawns and shrimps), Stomatopoda, anguilliformes and osteichthyes. Decapods were the most numerous prey item by both count (59.17% of total prey items) and weight (60.25% of total weight). Our study provides strong support that the Rewa River estuary is an important aggregation area for S. lewini in Fiji.

Very low numbers of endangered Oceania humpback whales seen in Fijian waters

Intensive commercial whaling caused significant declines in Southern Hemisphere humpback whale (Megaptera novaeangliae) populations. In Fiji, land-based humpback whale surveys undertaken from 1956 to 1958 documented maximum weekly counts of more than 150 humpback whales in parts of the Bligh waters. These records provide an invaluable point of comparison to present-day observations as they occurred immediately prior to very large humpback whale catches in Antarctic waters to the south – and on potential migration routes – of humpback whales breeding in Fijian waters. We report here on a three-year (2010–2012) land-based survey also conducted in the Bligh waters during which a total of 33 individuals over 480 h were counted from Ovalau Island and 68 individuals over approximately 300 h were observed from Makogai Island. These findings suggest a large decrease in numbers of humpback whales seen in Fiji waters since commercial whaling operations.

Proactive Cetacean Conservation in the Midst of ‘Data Deficiency’: Progress of the Convention on Migratory Species Cetacean Agreement in the Pacific Islands Region

The Pacific Islands Region is an expansive, tropical oceanic region containing 22 Pacific Island Countries and Territories (PICTs). In general, the PICTs have limited land area, are geographically isolated, contain unique endemic ecosystems vulnerable to destruction or damage, and have rapid human population growth rates. PICTs place a high value on their marine resources for both food security and livelihoods, recognizing their relatively high marine biodiversity, as well as cultural and traditional significance. Various regional and sub-regional management frameworks of differing spatial and temporal scales, numerous levels of stakeholder engagement, and specific areas or

Cetacean diversity, common occurrence and community importance in Fijian waters

Fiji has demonstrated a strong commitment to cetacean conservation via national, regional and international plans and agreements. To provide baseline information in support of these efforts, this paper provides an updated listing of cetacean species found in Fijian waters and identifies locations where cetaceans have been noted on a consistent basis. Information for this review was sourced from peer-reviewed publications, field reports, historical whaling records, national consultations, anecdotal and opportunistic sources, as well as a national database held by the Fiji Government’s Department of Fisheries. Reliable and recent records were confirmed for 10 cetacean species in Fijian waters. In addition, less reliable records and regional species’ information provides support for the occurrence of at least 14 additional species or groups of similar-looking species that could not be identified more specifically. Thirteen hotspot areas within the Fiji Economic Exclusive Zone were preliminarily identified as being particularly important for cetaceans, including numerous sites within the Vatu-i-Ra and Lomaiviti passages and surrounding waters. Issues with the available data include uneven coverage, inherent biases within available sources, and difficulties with species identification and verification in some cases. Nevertheless, it is hoped that this review will provide a reference point from which to move forward with cetacean management and conservation efforts in Fiji.