THE KEYNOTE SPEAKERS

Title of his presentation: Contrasting movement patterns of migratory and non-migratory baleen whale populations

  Long-range latitudinal migration has evolved in most baleen whales, whereas some populations and entire species have adapted to a non-migratory life cycle. In humpback whales, migration has evolved in conjunction with a seasonal fasting physiology, so that most populations do not feed during the months of the breeding season; conversely, non-migratory populations of humpback whales and other species feed throughout the year, including during the breeding season. To better understand the differences between these life history patterns, this presentation will contrast movement behavior of migratory and non-migratory populations of a migrating species (Southwest Indian Ocean and Arabian Sea humpback whales, respectively, SIOHW and ASHW), and a non-migratory species (Madagascar Omura’s whales, MOW). Satellite telemetry data were obtained from each population from published and ongoing studies, each with comparable tag transmission durations from one to two months (Cerchio et al. 2016 MEPS 652:193 and Trudelle et al. 2016 RSOS 3:160616 for SIOHW, Willson et al. 2016 IWC SC/66b/SH28 for ASHW, and Cerchio unpublished data for MOW). Despite having the shortest transmission durations, SIOHW displayed the most extensive total displacement from two tagging sites, ranging in an extensive corridor around 2/3 of Madagascar (excluding open-ocean migratory tracks). Conversely, MOW remained in a restricted range constrained to the northwest of Madagascar, whereas ASHW ranged over a coastal area intermediate in size but more similar to SIOHW. Daily displacement followed similarly, with SIOHW moving on average twice the daily distance as compared to MOW, and ASHW falling intermediate. Moreover, the daily-displacement/daily-total-track ratio was non-overlapping between SIOHW and MOW, emphasizing the much more directional movement patterns of SIOHW. Switching space state models indicated substantial differences in movement behavior with SIOHW displaying the most pervasive transiting behavior, compared to MOW being strongly skewed towards local (ARS) movements, as were ASHW. These contrasts are likely due to life history differences, with fasting SIOHW on the breeding grounds not constrained or influenced by feeding pressure, whereas movements of MOW are likely determined by distribution of food resources. ASHW, which have adapted to a non-migratory, non-fasting physiology, display similar trends to MOW, possibly due to similar feeding pressures, but simultaneously maintain a longer-ranging characteristic of the migratory populations in the Southern Hemisphere from which they diverged.

Title of his presentation: Predicting population consequences of disturbance on baleen whales

The need for managing non-lethal effects (i.e. human disturbance) on marine mammals is becoming increasingly important as exposure of marine mammals to human activities (e.g. shipping, naval activities, fisheries, renewable energy, oil and gas exploration and tourism) are rapidly intensifying globally. Human disturbance has been shown to have population level consequences for the targeted populations, however the underlying mechanism of how these effects arise, is unknown. To predict population consequences of disturbance (PCoD) on marine mammals, there is a need to determine how behaviour responses of exposed individuals can influence their vital rates (survival and reproduction) and ultimately population dynamics. My research focuses on determining PCoD in baleen whales, by determining the relationship between individual behaviour, bioenergetic, body condition, vital rates and population dynamics. My presentation will focus on some of the recent research that has been done around the world to determine PCoD in marine mammals, with an emphasis on baleen whales and the advances made in this field, as well as discussing some of the remaining challenges we face.

Title of his presentation: Light sometimes radiates from dark corners – the link between awareness and conservation success

Conservation as a science can be bewildering in its apparent complexity and often deceiving in its promises of delivery, particularly among its chief stakeholders. In practice conservation projects require extensive adaption to a local context, the outcomes are typically imperfect and hard to predict, and solutions are often linked to the scale of stakeholder awareness. Using examples from projects in Oman, Gabon and Angola, the intended and actual outcomes of conservation projects are compared and the importance of awareness explored. The Arabian Sea humpback whale population (ASHW) is the world’s smallest, most distinct and is uniquely non-migratory. Two decades of scientific and conservation effort in Oman have significantly raised the profile of this Endangered population. Current estimates of population size suggest that the population is not recovering and current management approaches to threats indicate that regional conservation awareness is poor. Recent stakeholder-led conservation initiatives in Oman and Pakistan suggest that solutions may be reached by raising community consciousness of ASHW, and empowering stakeholders to make meaningful contributions. In Gabon general awareness is even less apparent, but the country recently completed an extensive marine spatial planning process endorsed and supported by government. This included allocating 23% of the EEZ to MPAs and the development of management plans that include explicit consideration of current threats to humpback whales and other cetaceans. In Angola a research project funded by an oil company to address gaps in an environmental assessment led to the unintended identification of a significant threat to breeding humpback whales. Consensus on the scale of ‘threat’ was never reached but the project led to further research collaboration and a broader terms of reference. Conservation solutions for humpbacks and other cetaceans require considerable effort, particularly when awareness is poor. Improving awareness is a critical step that is often underestimated and without which future conservation will founder.

Title of her presentation: Feces, blow and baleen: Modern approaches to assessment of stress and reproduction in humpback whales using alternative sample types

Stress and reproduction have historically been difficult to study in baleen whales, largely due to the difficulty of collecting plasma samples for classic endocrinology measures of the stress hormones and reproductive hormones. Many basic reproductive and stress parameters such as exact gestation length, estrous cycling and inter-calving intervals in females, and testosterone cycling in males remain uncertain, even in well-studied species such as the humpback whale, Megaptera novaeangliae. Over the past two decades, however, a variety of novel hormone techniques have been developed that use alternative sample types, including feces, respiratory vapor (« blow »), baleen, earplugs, and even skin scrapings, in conjunction with photography based methods such as photo-identification and aerial photogrammetry. Most of these methods have been trialed successfully in the Balaenidae (primarily with North Atlantic right whales, Eubalaena glacialis, and bowhead whales, Balaena mysticetus) and are now ready for testing in other taxa. In the last several years, fecal sampling, respiratory vapor sampling and baleen hormone analysis have all been trialed successfully with humpback whales of the Gulf of Maine. This talk will review the state of the art for humpback whale hormone techniques, the validation issues that must still be addressed, and will present recommendations for next steps in extending these promising techniques to studies of stress and reproduction in humpback whales.

Title of his presentation: Age estimation in humpback whales by analysis of DNA methylation

Animal age is an important ecological feature. It is linked to many individual characteristics such as reproductive capacity, foraging ability and likelihood of mortality. At the population level, the proportions of animals in different age classes affects future population growth rates and reflects past demographic events. However, estimating the age of anonymous individuals from many wild animal species is often impossible. Humpback whales are a classic example of this as they mature sexually after 5-8 years, reach maximum size one or two years after that and subsequently have no external features that allow their age to be estimated in cross-sectional studies. Attempts to establish non-lethal age estimation methods initially focused on telomere length assays, but these were not effective. More recently, a different molecular age biomarker was developed based on measurement of DNA methylation levels at a combination of three specific CpG sites. In this talk, I will discuss why age estimation is useful for humpback whale population biology; the history of age estimation in humpbacks; the key features and limitations of the current DNA-methylation based methodology; and the future prospects for age estimation in this species.

Title of his presentation: Twenty years of sizing whales underwater: Insights into the behavioral ecology and mating system of humpback whales in the Hawaiian breeding grounds

In many species, body size is an important factor in the breeding success of individuals. Larger females may be more fecund and/or better able to produce and rear higher-quality offspring than smaller females, and larger males may be more successful in securing females than smaller males. Early observations of humpback whales in their breeding grounds allowed researchers to describe their basic social organization, displays and interactions. Yet little was known about the role of body size in these various aspects of humpback whale society. For over two decades, we have been using underwater videogrammetry in the Hawaiian breeding grounds to measure the body sizes of humpback whales. Over 500 whales have been measured, and whale size has been related to the maturity of individuals, their behaviors, behavioral roles, social interactions, and habitat use. Findings have revealed that male size confers an advantage in male-male competition over females, that a female’s size is related to the size of her calf and the numbers of escorts she attracts, that body size influences how males and females form dyads, that males of varying size and maturity sing, and that calf size and maturity influence maternal female habitat use. When integrated with our other data from boat-based surveys, shore-based observations, hydrophone array deployments, and suction cup video and acoustic recorder tagging studies, these findings portray a rich picture of humpback whale society in the breeding grounds and demonstrate that indeed, size does matter.

Title of his presentation: Changes in baleen whale abundance, distribution and migration during present and past climate changes

Environmental changes, especially periods of global warming and cooling, have profound and lasting effects upon species distribution and abundance. In this talk, I present the inferences drawn from contemporary population genetic data in six different baleen whale species in two Hemispheres regarding past and present effects of climate change. The Southern Ocean is characterized by highly synchronous, dramatic and long-lasting effects in abundance which correlate with prey abundances. In contrast, the more complex North Atlantic revealed pronounced regional differences reflective of the more heterogeneous oceanographic conditions in this ocean. Recent global warming has changed migration timing and destination resulting in pronounced changes in the local genetic make-up of feeding grounds during one decade. Changes in abundance and glaciations is also reflected in migration rates enhancing and reducing connectivity even among ocean basins.

Title of her presentation: Humpback Hyoid: A New Function for an Old Bone

The hyoid is a tiny bone in the neck associated with positioning the mandible, tongue, and larynx, and is used in digestive/respiratory tract functions (chewing, swallowing, breathing, and vocalizing). The hyoid in toothed whales is also used to withdraw the tongue caudally into the throat to generate negative pressure in the mouth to suck in whole prey. In rorqual baleen whales, such as humpbacks, it helps contract the throat pleats during engulfment feeding to force water out of the ventral pouch. We now propose a new and unusual role in whales: locomotion. This unique function is based on the large surface area of this bone that supports ventral axial musculature connecting the skull to the thorax. Musculoskeletal anatomy of the hyoid apparatus was studied in ten specimens of humpback whales (Megaptera novaeangliae). Results indicate the humpback hyoid apparatus consists of only an unpaired basihyal and paired thyrohyals to make the basal element (usually called just “hyoid”), plus a pair of stylohyals that attach the hyoid to the base of the skull in the ear region. The ceratohyals, epihyals, and tympanohyals (found in other animals as part of the hyoid suspensory apparatus) appear to be either missing, or have become cartilaginous or ligamentous structures. The humpback hyoid is hypertrophied compared with other animals. It consists of a thick basihyal and cylindrical thyrohyals. Two paired extensions of the basihyal are directed both rostrally and caudally. Several muscles attached to the hyoid, including hyoglossus and styloglossus (to tongue), stylohyoid (to skull), thyrohyoid and hyoepiglotticus (also to larynx), and ceratohyoid (between thyrohyals and stylohyals). The rostral basihyal extensions are larger than the caudal extensions, and provide extra surface area for a membrane that supports attachment of the mylohyoid and geniohyoid muscles (connecting the hyoid to the chin). The caudal basihyal extensions are positioned more laterally, and similarly support a membrane that allowed increased surface area for the attachment of the sternohyoid muscle (connecting the hyoid to the chest). These basihyal muscles are aligned in the longitudinal axis, connecting the mandible with the sternum. Contraction of these hyoid muscles (with the mandible held closed) appears to cause atlanto-occipital joint kyphosis (skull-cervical flexion), thus pointing the rostrum ventrally. This movement initiates a body wave (dorso-ventral displacement) that can be propagated caudally along the axial skeleton. As the wave propagates, the amplitude builds. This wave likely assists in exaggerating the large tail movements that provide thrust. The cetacean hyoid is thus proposed to have a new function in locomotion.

Title of his presentation: The relationship between census size (N) and effective size (Ne) in humpback whale populations

The ecological/demographic consequences of population abundance (population growth rate, competition, predation, etc.) depend on the census size (the total number of individuals, N, or the number of adults, NA), while the evolutionary consequences (rate of increase in inbreeding; rate of allele frequency change; rate of loss of genetic variability) depend on the effective population size (Ne). The ratio Ne/N is of considerable interest to biologists because in many species one parameter is easier to estimate than the other, so if the ratio is known one can crosswalk between the two parameters. The following information is needed to calculate N, Ne, and Ne/N in natural populations: number of calves produced each year; age at maturity, age-specific survival, and age-specific fecundity (separately for each sex); variance in reproductive success among males, for each age; breeding interval for females. Using empirical data for these life history traits in humpback whales, I compute likely ranges for the key ratio Ne/N and identify the factors that have the greatest influence on the ratio.