Lions, whales, and the web : transforming moment inertia into conservation action

When Farley Mowat wrote A Whale for the Killing in 1972, the titular fin whale, stranded and intentionally wounded in a Newfoundland pond, was long dead, yet the story of Moby Joe and the spectacle surrounding her death would become a cornerstone of the emerging anti-whaling movement (see below). The media frenzy that descended on the small town of Burgeo as the whale struggled to survive, and the subsequent publication of Mowat's book, are among the first examples of efforts to turn spontaneous outpourings of outrage, curiosity, or empathy into conservation action by actively focusing media attention, a phenomenon that we have dubbed moment inertia. We use “moment” because this phenomenon arises from focus of attention around a single, clarifying event, or moment, and “inertia” because that attention propagates, undirected, through media unless acted upon by outside forces, much like physical inertia. Almost half a century later, the events leading to the publication of A Whale for the Killing stand among the most effective uses of moment inertia in the conservation movement

Whatcha saying? Evidence of production learning in a solitary common dolphin during interspecific interactions with a harbour porpoise

Several cetacean species have the ability to change their acoustic repertoire (i.e., production learning) as a result of interactions with other species. This ability has mainly been observed in captive individuals and few cases have been reported for wild cetaceans. A long-term affiliative association between a solitary short-beaked common dolphin (henceforth common dolphin) and a harbour porpoise in West Scotland provided the opportunity to study this ability in wild cetaceans. Harbour porpoises produce entirely stereotyped narrow-band high-frequency echolocation clicks with peak frequencies around 130kHz. Clicks are emitted in trains and used for travelling, foraging, and communication purposes. Common dolphins’ echolocation clicks are widely understudied. Available data suggests these are frequency banded (i.e., with distinct peaks and notches in their power spectrum) with peak frequencies below 67kHz. Common dolphins also produce other sounds for communication purposes, including whistles and barks. Data was collected during systematic and opportunistic surveys using a towed hydrophone array. Vocalisations of both species were recorded when interacting as well as when seen alone. Using custom-built algorithms, individual dolphin and porpoise echolocation clicks were extracted, and several parameters estimated, including amplitude, and peak and centroid frequencies. The dolphin regularly produced clicks with peak and centroid frequencies over 100kHz, centred around 120kHz, when accompanied by the harbour porpoise, as well as when alone. Typically, the centroid frequency varied within a click train, between values below 50kHz to over 140kHz. Other sounds were detected, including barks and buzzes, however no whistles were recorded. No changes in the porpoise acoustic repertoire were detected. The preliminary results of this study suggest the common dolphin changes its acoustic repertoire, likely as a result of the interaction with a harbour porpoise. This is the first time the common dolphins’ ability for production learning (in the wild or in captivity) has been reported

D-PorCCA, a new tool to study the behaviour of harbour porpoises

The behaviour of harbour porpoises can be deduced from the variation pattern of their vocalisations. They produce only narrow-band high-frequency (NBHF) clicks, emitted in so-called click trains. Therefore, available acoustic recordings can be used to increase our understanding of their behaviour. Behavioural studies, however, are time consuming and require an accurate, automated classifier and a click train identifier. Here, we present D-PorCCA, a graphical user interface to study recordings from harbour porpoises in the wild. D-PorCCA is an independent tool developed in Matlab and includes an impulsive-sound detector and a new high-accuracy porpoise click classifier (PorCC). PorCC classifies each signal as either: noise (N), low-quality (LQ), or high-quality (HQ) porpoise click. The user can decide on the echolocation events they want to visualise, specifying the length of the click train (including both HQ and LQ clicks) and the minimum separation time between echolocation events. These events are plotted as time vs amplitude, vs inter-click interval, and vs centroid frequency (or direction of arrival, if available). Additionally, the waveform, power spectrum, and spectrogram of each click within the echolocation event is available. Click trains of interest can be easily selected by the user and extracted for further analysis. These events are then automatically cleaned of echoes and other noise sources, after which the pattern of the click train is automatically investigated to determine whether there is one or more animals vocalising simultaneously (i.e., overlapping click trains), as well as which behaviour the animal was potentially engaged in (e.g., feeding). D-PorCCA is a user-friendly tool with potential for behavioural studies of wild harbour porpoises as well as other NBHF species, as it focuses on clicks trains, and can be used to fill knowledge gaps of these elusive species. Moreover, it has potential for application in large monitoring project, such as SAMBAH

I beg your pardon? Acoustic behaviour of a wild solitary common dolphin who interacts with harbour porpoises

Kylie is a solitary common dolphin who inhabits a restricted area within the Firth of Clyde (Scotland). She spends most of her time around navigational buoys in the Hunterston/Fairlie channel, where she has been seen interacting with harbour porpoises. Recordings from 2016 and 2017 were used to study her acoustic behaviour when seen alone and with a porpoise. Clicks were classified as potential porpoise or dolphin clicks based on the waveform, power spectrum, and spectrogram, as well as direction of arrival, inter-click interval, amplitude, and centroid frequency variations. Kylie emitted clicks exclusively, which were of variable nature, including low, mid, and high-frequency (HF, centroid frequency > 100 kHz) as well as broad or narrowband. Some of Kylie's HF clicks were similar to porpoise clicks both in the time (e.g., polycyclic) and frequency (e.g., narrowband with most energy between 100 and 150 kHz) domains, which cannot be explained by physical phenomenon alone

Porpoise Click Classifier (PorCC) : a high-accuracy classifier to study harbour porpoises (Phocoena phocoena) in the wild

Harbour porpoises are well-suited for passive acoustic monitoring (PAM) as they produce highly stereotyped narrow-band high-frequency (NBHF) echolocation clicks. PAM systems must be coupled with a classification algorithm to identify the signals of interest. Here, we present a harbour porpoise click classifier (PorCC) developed in MATLAB, which uses the coefficients of two logistic regression models in a decision-making pathway to assign candidate signals to one of three categories: high-quality clicks (HQ), low-quality clicks (LQ), or high-frequency noise (N). The receiver operating characteristics of PorCC was compared to that of PAMGuard's Porpoise Click Detector/Classifier Module. PorCC outperformed PAMGuard’s classifier achieving higher hit rates (correctly classified clicks) and lower false alarm levels (noise classified as HQ or LQ clicks). Additionally, the detectability index (d') for HQ clicks for PAMGuard was 2.2 (overall d' = 2.0) versus 4.1 for PorCC (overall d' = 3.4). PorCC classification algorithm is a rapid and highly accurate method to classify NBHF clicks, which could be applied for real time monitoring, as well as to study harbour porpoises, and potentially other NBHF species, throughout their distribution range from data collected using towed hydrophones or static recorders. Moreover, PorCC is suitable for studies of acoustic communication of porpoises

Widespread Use of Migratory Megafauna for Aquatic Wild Meat in the Tropics and Subtropics

Wild animals are captured or taken opportunistically, and the meat, body parts, and/or eggs are consumed for local subsistence or used for traditional purposes to some extent across most of the world, particularly in the tropics and subtropics. The consumption of aquatic animals is widespread, in some places has been sustained for millennia, and can be an important source of nutrition, income, and cultural identity to communities. Yet, economic opportunities to exploit wildlife at higher levels have led to unsustainable exploitation of some species. In the literature, there has been limited focus on the exploitation of aquatic non-fish animals for food and other purposes. Understanding the scope and potential threat of aquatic wild meat exploitation is an important first step toward appropriate inclusion on the international policy and conservation management agenda. Here, we conduct a review of the literature, and present an overview of the contemporary use of aquatic megafauna (cetaceans, sirenians, chelonians, and crocodylians) in the global tropics and subtropics, for species listed on the Appendices of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). We find that consumption of aquatic megafauna is widespread in coastal regions, although to varying degrees, and that some species are likely to be at risk from overexploitation, particularly riverine megafauna. Finally, we provide recommendations for CMS in the context of the mandate of the Aquatic Wild Meat Working Group.Additional co-authors: Jeffrey W. Lang, Sigrid Lüber, Charlie Manolis, Grahame J. W. Webb and Lindsay Porte

Widespread use of migratory megafauna for aquatic wild meat in the tropics and subtropics

Wild animals are captured or taken opportunistically, and the meat, body parts, and/or eggs are consumed for local subsistence or used for traditional purposes to some extent across most of the world, particularly in the tropics and subtropics. The consumption of aquatic animals is widespread, in some places has been sustained for millennia, and can be an important source of nutrition, income, and cultural identity to communities. Yet, economic opportunities to exploit wildlife at higher levels have led to unsustainable exploitation of some species. In the literature, there has been limited focus on the exploitation of aquatic non-fish animals for food and other purposes. Understanding the scope and potential threat of aquatic wild meat exploitation is an important first step toward appropriate inclusion on the international policy and conservation management agenda. Here, we conduct a review of the literature, and present an overview of the contemporary use of aquatic megafauna (cetaceans, sirenians, chelonians, and crocodylians) in the global tropics and subtropics, for species listed on the Appendices of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). We find that consumption of aquatic megafauna is widespread in coastal regions, although to varying degrees, and that some species are likely to be at risk from overexploitation, particularly riverine megafauna. Finally, we provide recommendations for CMS in the context of the mandate of the Aquatic Wild Meat Working Group