Embracing conservation success of recovering humpback whale populations: Evaluating the case for downlisting their conservation status in Australia

Optimism and hope in conservation biology are supported by examples of endangered species recovery, such as the population growth observed in humpback whales in several of the world's oceans. In Australia, monitoring data suggest rapid recovery for both east and west coast populations, which are now larger than 50% of their pre-whaling abundance. The measured growth rates exceed known species trends worldwide and have no indication of diminishing. Under Australian Commonwealth legislation and regulations, these populations should be considered for downlisting, as they are not eligible for listing as a threatened species against all statutory criteria. A change in conservation status will produce new challenges for the conservation and management of a recovered species, especially with the Australian economic landscape experiencing large-scale growth and development in recent years. More importantly, a recovered humpback whale population may bring a positive shift in the research goals and objectives throughout Australia by ensuring other endangered species an equal chance of recovery while delivering hope, optimism, and an opportunity to celebrate a conservation success

Implications of survey effort on estimating demographic parameters of a long-lived marine top predator

Effective management of wildlife populations rely on knowledge of their abundance, survival, and reproductive rates. Maintaining long‐term studies capable of estimating demographic parameters for long‐lived, slow‐reproducing species is challenging. Insights into the effects of research intensity on the statistical power to estimate demographic parameters are limited. Here, we investigate implications of survey effort on estimating abundance, home range sizes, and reproductive output of Indo‐Pacific bottlenose dolphins (Tursiops aduncus), using a 3‐year subsample of a long‐term, capture–recapture study off Bunbury, Western Australia. Photo‐identification on individual dolphins was collected following Pollock's Robust Design, where seasons were defined as “primary periods”, each consisting of multiple “secondary periods.” The full dataset consisted of 12 primary periods and 72 secondary periods, resulting in the study area being surveyed 24 times/year. We simulated reduced survey effort by randomly removing one, two, or three secondary periods per primary period. Capture–recapture models were used to assess the effect of survey intensity on the power to detect trends in population abundance, while individual dolphin sighting histories were used to assess the ability to conduct home range analyses. We used sighting records of adult females and their calving histories to assess survey effort on quantifying reproductive output. A 50% reduction in survey effort resulted in (a) up to a 36% decline in population abundance at the time of detection; (b) a reduced ability to estimate home range sizes, by increasing the time for individuals to be sighted on ≥30 occasions (an often‐used metric for home range analyses) from 7.74 to 14.32 years; and (c) 33%, 24%, and 33% of annual calving events across three years going undocumented, respectively. Results clearly illustrate the importance of survey effort on the ability to assess demographic parameters with clear implications for population viability analyses, population forecasting, and conservation efforts to manage human–wildlife interactions

Food-provisioning negatively affects calf survival and female reproductive success in bottlenose dolphins

Food-provisioning of wildlife can facilitate reliable up-close encounters desirable by tourists and, consequently, tour operators. Food-provisioning can alter the natural behavior of an animal, encouraging adverse behavior (e.g. begging for food handouts), and affect the reproductive success and the viability of a population. Studies linking food-provisioning to reproductive success are limited due to the lack of long-term datasets available, especially for long-lived species such as marine mammals. In Bunbury, Western Australia, a state-licensed food-provisioning program offers fish handouts to a limited number of free-ranging bottlenose dolphins (Tursiops aduncus). Coupled with long-term historical data, this small (<200 individuals), resident dolphin population has been extensively studied for over ten years, offering an opportunity to examine the effect of food-provisioning on the reproductive success of females (ntotal = 63; nprovisioned females = 8). Female reproductive success was estimated as the number of weaned calves produced per reproductive years and calf survival at year one and three years old was investigated. The mean reproductive success of provisioned and non-provisioned females was compared using Bayes factor. We also used generalized linear models (GLMs) to examine female reproductive success in relation to the occurrence of food-provisioning, begging behavior and location (within the study area). Furthermore, we examined the influence of these variables and birth order and climatic fluctuations (e.g. El Niño Southern Oscillation) on calf survival. Bayes factor analyses (Bayes factor = 6.12) and results from the best fitting GLMs showed that female reproductive success and calf survival were negatively influenced by food-provisioning. The negative effects of food-provisioning, although only affecting a small proportion of the adult females’ population (13.2%), are of concern, especially given previous work showing that this population is declining

Identifying important resting habitats for the protection of Hawaiian spinner dolphins

With the ever increasing intrusion of anthropogenic activities on wildlife habitats, linking environmental characteristics with behavioural activities is vital for the identification and protection of critical habitats (i.e. those supporting essential life functions such as foraging, breeding or resting)

Morphological differences between coastal bottlenose dolphin (Tursiops aduncus) populations identified using non-invasive stereo-laser photogrammetry

Obtaining morphometric data on free-ranging marine megafauna is difficult, as traditional methods rely on post-mortem or live-capture techniques. We linked stereo-laser photogrammetry with long-term demographic data to compare length-at-age (LaA) growth curves of two well-studied populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in south-western (SW) and Shark Bay (SB), mid-western Australia. First, we determined the relationship between total length (TL) and blowhole-to-dorsal fin (BH-DF) length from post-mortem subjects (R2 = 0.99, n = 12). We then predicted TL from laser-derived BH-DF measurements of 129 and 74 known-age individuals in SW and SB, respectively. Richards growth models best described our LaA data. While birth length (103–110 cm) was similar between study regions, TL estimates at 1, 3, 12, and 25 years differed significantly (p < 0.001). Asymptotic length of adult males (SW = 246 cm, SB = 201 cm) and females (SW = 244 cm, SB = 200 cm) also differed significantly. Morphotypic variations likely reflect regional adaptations to local water temperatures, with the temperate SW having cooler waters than sub-tropical SB. We demonstrate the effectiveness of a non-invasive technique to understand ecological, demographic and life-history characteristics of long-lived marine megafauna, which are critical parameters for informing conservation and management actions

Sex-specific patterns in demography of bottlenose dolphins in coastal and estuarine waters

Inherent difficulties in determining the sex of free-ranging, sexually monomorphic species (where both sexes look the same) often prevents a sex-specific approach to their study. However, accounting for sex-differences in population parameters can have important conservation and management implications, as one sex may be more susceptible to threats than the other

Editorial: Small cetacean conservation: Current challenges and opportunities

Dolphins (oceanic and river dolphins; Delphinidae, Iniidae, Lipotidae, Pontoporiidae, Platanistidae) and porpoises (Phocoenidae) are the smallest members of the odontocete suborder. These species have colonized most aquatic ecosystems globally, from rivers to deep oceanic habitats, and from tropical to polar waters. Due to their habitat preferences, high metabolic rates, foraging behaviors, and diets, small cetaceans exhibit a wide range of ecological roles and functions across ecosystems where they occur and have the potential to affect communities via multiple pathways (top-down, bottom-up effects, and a range of behavior-mediated processes, Kiszka et al.). Dolphins and porpoises have also generated significant interest from the scientific community and more broadly by human societies since antiquity, with research on these animals increasing exponentially over the past 40-50 years. Despite protection by a range of international conventions (e.g., Convention on Migratory Species, Convention on the Trade of Endangered Species) and national legislation in most countries, some species are at increasing risk of decline and extirpation in aquatic habitats worldwide, with losses driven by a range of direct and indirect impacts from human activities. Today, more than 20% of species of oceanic dolphins, half of all species of porpoise, and all river dolphins are threatened with extinctionFil: Kiszka, Jeremy J.. Florida International University; Estados UnidosFil: Bejder, Lars. University of Hawaii at Manoa; Estados UnidosFil: Davis, Randall. Texas A&M University; Estados UnidosFil: Harcourt, Rob. Macquarie University; AustraliaFil: Meekan, Mark. University of Western Australia; AustraliaFil: Rodriguez, Diego Horacio. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Stockin, Karen A.. Massey University; Nueva Zeland

Anthropogenic Threats to Wild Cetacean Welfare and a Tool to Inform Policy in This Area

Human activities and anthropogenic environmental changes are having a profound effect on biodiversity and the sustainability and health of many populations and species of wild mammals. There has been less attention devoted to the impact of human activities on the welfare of individual wild mammals, although ethical reasoning suggests that the welfare of an individual is important regardless of species abundance or population health. There is growing interest in developing methodologies and frameworks that could be used to obtain an overview of anthropogenic threats to animal welfare. This paper shows the steps taken to develop a functional welfare assessment tool for wild cetaceans (WATWC) via an iterative process involving input from a wide range of experts and stakeholders. Animal welfare is a multidimensional concept, and the WATWC presented made use of the Five Domains model of animal welfare to ensure that all areas of potential welfare impact were considered. A pilot version of the tool was tested and then refined to improve functionality. We demonstrated that the refined version of the WATWC was useful to assess real-world impacts of human activity on Southern Resident killer whales. There was close within-scenario agreement between assessors as well as between-scenario differentiation of overall welfare impact. The current article discusses the challenges raised by assessing welfare in scenarios where objective data on cetacean behavioral and physiological responses are sparse and proposes that the WATWC approach has value in identifying important information gaps and in contributing to policy decisions relating to human impacts on whales, dolphins, and porpoises

Effects of vessel traffic on relative abundance and behaviour of cetaceans : the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea

Acknowledgements This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco (CTS) and by the National Park of the Archipelago de La Maddalena. We thank the Natural Reserve of Bocche di Bonifacio for the support provided during data collection. The authors thank the numerous volunteers of the Caprera Dolphin Research Centre and especially Marco Ferraro, Mirko Ugo, Angela Pira and Maurizio Piras whose assistance during field observation and skills as a boat driver were invaluable.Peer reviewedPostprin

Meta-analyses of whale-watching impact studies : Comparisons of cetacean responses to disturbance

Acknowledgements. The International Whaling Commission funded this study through a grant assigned to D.L. D.L. was also funded by the Scottish Funding Council for funding through grant HR09011 to the Marine Alliance for Science and Technology for Scotland. While writing the manuscript, V.S. was sponsored by a Fulbright scholarship. We thank the many people that replied to the 2 MAR - MAM calls and Dr. Stankowich for his previous comments on the manuscript.Peer reviewedPublisher PD