Thermal reference points as an index for monitoring body temperature in marine mammals

Infrared Thermography of the Blowhole as a Potential Diagnostic Tool for Health Assessment in Killer Whales (Orcinus orca)

Killer whales (Orcinus orca) are experiencing increasing environmental pressures, with some ecotypes being identified as endangered, and the development and validation of non-invasive health assessment tools is critical for assessing the well-being of individuals within these endangered populations. Infrared thermography of the blowhole is a non-contact method of temperature measurement that was recently investigated in killer whales in managed care. Two male killer whales presenting with clinical signs at separate institutions had veterinary clinical health assessments performed, which included infrared thermography of the blowhole as well as concurrent rectal temperature measurement. The current case report is aimed at describing the clinical use of infrared thermography of the blowhole as a method to detect elevated body temperature in two killer whales. Both animals exhibited blowhole temperatures above the previously reported values (36.4 °C and 37.6 °C; the mean in healthy whales is reported to be 34.21 ± 1.47 °C) with concurrently elevated rectal temperatures, as well as clinicopathologic findings consistent with a systemic inflammatory response (e.g., neutrophilia, increased fibrinogen and erythrocyte sedimentation rate, hypoferritinemia). Following veterinary intervention, both animals' blowhole and rectal temperatures returned to baseline. Infrared thermography of the blowhole represents a promising tool for the identification of pyrexic animals and with further investigation may be considered as part of conservation health assessments for threatened free-ranging populations.

Phylogeography and host specificity of Pasteurellaceae pathogenic to sea-farmed fish in the north-east Atlantic

The present study was undertaken to address the recent spate of pasteurellosis outbreaks among sea-farmed Atlantic salmon (Salmo salar) in Norway and Scotland, coinciding with sporadic disease episodes in lumpfish (Cyclopterus lumpus) used for delousing purposes in salmon farms. Genome assemblies from 86 bacterial isolates cultured from diseased salmon or lumpfish confirmed them all as bona fide members of the Pasteurellaceae family, with phylogenetic reconstruction dividing them into two distinct branches sharing <88% average nucleotide identity. These branches therefore constitute two separate species, namely Pasteurella skyensis and the as-yet invalidly named "Pasteurella atlantica". Both species further stratify into multiple discrete genomovars (gv.) and/or lineages, each being nearly or fully exclusive to a particular host, geographic region, and/or time period. Pasteurellosis in lumpfish is, irrespective of spatiotemporal origin, linked almost exclusively to the highly conserved "P. atlantica gv. cyclopteri" (Pac). In contrast, pasteurellosis in Norwegian sea-farmed salmon, dominated since the late-1980s by "P. atlantica gv. salmonicida" (Pas), first saw three specific lineages (Pas-1, -2, and -3) causing separate, geographically restricted, and short-lived outbreaks, before a fourth (Pas-4) emerged recently and became more widely disseminated. A similar situation involving P. skyensis (Ps) has apparently been unfolding in Scottish salmon farming since the mid-1990s, where two historic (Ps-1 and -2) and one contemporary (Ps-3) lineages have been recorded. While the epidemiology underlying all these outbreaks/epizootics remains unclear, repeated detection of 16S rRNA gene amplicons very closely related to P. skyensis and "P. atlantica" from at least five cetacean species worldwide raises the question as to whether marine mammals may play a part, possibly as reservoirs. In fact, the close relationship between the studied isolates and Phocoenobacter uteri associated with harbor porpoise (Phocoena phocoena), and their relatively distant relationship with other members of the genus Pasteurella, suggests that both P. skyensis and "P. atlantica" should be moved to the genus Phocoenobacter.

How does habitat influence metabolism? Clues from biomarker response and contaminant profile in Tursiops truncatus (Montagu, 1821) subspecies living in parapatry

In western South America (WSA) two subspecies of bottlenose dolphin are recognized: Tursiops truncatus gephyreus, predominantly found in estuaries and river mouths, and Tursiops truncatus truncatus, occurring along the continental shelf. Despite a partial spatial overlap, both subspecies are considered to occupy different habitats and ecological niches. In the present study, chemical analyzes as well as biochemical and molecular biomarkers were used to investigate the influence of niche partitioning over metabolic pathways associated with the detoxification of persistent organic pollutants (POPs), antioxidant metabolism, immune activity and lipid metabolism in Tursiops truncatus subspecies living in parapatry. Overall, the profile and levels of bioaccumulated PCBs, pesticides and PBDEs were similar between groups, with a greater variety of pesticides, such as γ-HCHs, heptachlor, oxychlordane and o,p'DDT, detected in T. truncatus gephyreus. Multivariate analysis of variance (MANOVA) and non-metric multidimensional scaling (NMDS) results indicated that glutathione reductase (GR) and superoxide dismutase (SOD) enzymatic activities were higher in coastal dolphins, as were the mRNA levels of metallothionein 2A (MT2A), interleukin-1α (IL-1α), ceramide synthase 3 (CERS3) and fatty acid elongase (ELOVL4). In parallel, mRNA levels of fatty acid synthase complex 1 (FASN 1) were higher in oceanic dolphins. These findings suggest that, due to their occurrence in coastal habitats, T. truncatus gephyreus is more exposed to environmental pollutants and pathogenic microorganisms. Likewise, niche partitioning may influence lipid biosynthesis, possibly due to differences on feeding habits, reflecting in an enhanced long chain ceramides biosynthesis in T. truncatus gephyreus. Collectively, these data reinforce the need to address habitat specificities in conservation efforts, since distinct groups can be facing different anthropogenic pressures in WSA.

Thermal Imaging to Assess the Health Status in Wildlife Animals under Human Care: Limitations and Perspectives

Promoting animal welfare in wildlife species under human care requires the implementation of techniques for continuously monitoring their health. Infrared thermography is a non-invasive tool that uses the radiation emitted from the skin of animals to assess their thermal state. However, there are no established thermal windows in wildlife species because factors such as the thickness or color of the skin, type/length of coat, or presence of fur can influence the readings taken to obtain objective, sensitive values. Therefore, this review aims to discuss the usefulness and application of the ocular, nasal, thoracic, abdominal, and podal anatomical regions as thermal windows for evaluating zoo animals' thermal response and health status. A literature search of the Web of Science, Science Direct, and PubMed databases was performed to identify relevant studies that used IRT with wild species as a complementary diagnostic tool. Implementing IRT in zoos or conservation centers could also serve as a method for determining and monitoring optimal habitat designs to meet the needs of specific animals. In addition, we analyze the limitations of using IRT with various wildlife species under human care to understand better the differences among animals and the factors that must be considered when using infrared thermography.

Predation of satellite-tagged juvenile loggerhead turtles Caretta caretta in the Northwest Atlantic Ocean

We present evidence of predator interactions with 8 juvenile loggerhead sea turtles Caretta caretta equipped with pop-up satellite archival transmitting tags (PSATs) following incidental capture in the Northwest Atlantic. Ingestion of PSATs occurred up to 5 mo after tagging and was identified by an abrupt change in depth distribution, a stabilization and/or increase in ambient temperature and a marked drop in light levels to near zero, with cessation of diel light level cycling. In some cases, following expulsion from the digestive tract of predators, positively buoyant PSATs descended to the sea floor or beyond the programmed release depth threshold (1800 m), indicating that they remained tethered to the indigestible carapaces of turtles and that the entire turtle was originally consumed. PSAT data, combined with the sudden termination of satellite uplinks from 2 loggerheads also equipped with platform transmitting terminals, provided additional evidence of whole-turtle predation. PSAT data indicated that both endothermic and ectothermic sharks ingested tags. Based on PSAT-logged temperature data, dive patterns and geographic distribution, the following shark species were considered as candidate predators: white, porbeagle, shortfin mako, tiger and blue. This study represents the first analysis of data collected by loggerhead turtle PSATs inside predators. The results expand the list of shark species known to prey on large juvenile loggerheads and point to the importance of acknowledging predation as an important source of mortality for loggerhead turtles in the Northwest Atlantic Ocean.