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Presence of newborn humpback whale ( Megaptera novaeangliae ) calves in Gold Coast Bay, Australia
Abstract
The majority of humpback whales (Megaptera novaeangliae) undertake an annual migration from high latitude feeding grounds to tropical/subtropical breeding grounds. Suitable calving habitat for this species includes warm (typically 19°C to 28°C), shallow, sheltered waters in tropical and subtropical waters. Here, we investigated occurrence of calving beyond the primary recognised breeding grounds (16° to 24°S) of the east Australian humpback whale population (E1). We examined location, depth (m), and SST (⁰C) associated with newborn observations in Gold Coast Bay, in southern Queensland, Australia from 2013 to 2016. A total of 74 newborns were recorded in the study area, with the majority observed in July and August. These findings may signify that the Gold Coast Bay provides an apparently suitable habitat for calving for this humpback whale population. As the area has not been classified as calving habitat, these findings will assist conservation managers in making informed management decisions regarding this species.
... Most research on the humpback whale aggregation areas along the E1 population migration route has focused primarily on the pod characteristics Franklin et al. 2011) and migratory movements (Burns et al. 2014) of the whales. Several recent studies have demonstrated that breeding and calving behaviours have occurred outside recognised habitat areas for humpback whale populations (Bruce et al. 2014;Lucena et al. 2016;Irvine et al. 2018;Torre-Williams et al. 2019;Valani et al. 2020), underlining the need to further determine critical habitats, which we define as any habitat relevant for maintaining a stable population through feeding, breeding and resting. ...
... Few behavioural studies have been conducted in this location to determine the use of the bay by humpback whales (Meynecke et al. 2013;Reinke et al. 2016;Valani et al. 2020) and there is still limited knowledge about its exact function for socialisation and breeding. Recent research has demonstrated that parturition occurs outside the stated breeding grounds in the Great Barrier Reef, and evidence of newborn calves in the GCB suggests it is a suitable calving ground (Torre-Williams et al. 2019;Valani et al. 2020). ...
... The monitoring of Australian populations of humpback whales has increasingly been done through citizen science to find spatiotemporal and behavioural trends for this species (Bruce et al. 2014;Thums et al. 2018;Torre-Williams et al. 2019), including in the GCB and Hervey Bay (Franklin et al. 2011;Meynecke et al. 2013;Valani et al. 2020). Due to the limitations of systematic, long-term research (Silvertown 2009), large-scale ecological studies are difficult to facilitate, and even more so for migratory animals with a large spatial range (Dunn et al. 2019). ...
Humpback whales (Megaptera novaeangliae) require a suite of essential habitats during their long migration. Therefore, the identification of critical habitats is important for continuation of their successful recovery. In this study we investigated the behaviours and habitat usage exhibited by humpback whales in two known aggregation sites on the east coast of Australia. Using a combined 5400 humpback whale records collected from Hervey Bay between 1999 and 2009 and from the Gold Coast Bay between 2011 and 2018, we analysed different types of behavioural categories. We found that humpback whales in Hervey Bay primarily exhibited surface travel and non-aggressive social behaviour, whereas both sites appeared to be similarly important for resting. Our results suggest that the Gold Coast Bay provides habitat for a wide range of critical humpback whale activities, in particular for resting mother–calf pairs, mature males seeking copulation and socialising immature whales. Hervey Bay had a higher number of mother–calf pair sightings, confirming the area as an important resting site. This study demonstrates that the two regions are critical habitats for humpback whales during their annual migration, but for different essential activities, and should be considered as a whale protection area.
... These areas have been the focus of active research, suggesting that other parts of the coastline may also serve as resting areas for mother-calf pairs. Moreover, a southern expansion of the calving area has been suggested, with newborn calves sighted during the northern migration in the GCB in south-eastern Queensland (Torre-Williams et al. 2019). It remains unclear whether shifts in ocean conditions induced by climate change or an increase of the population is driving such an expansion of breeding areas. ...
... It remains unclear whether shifts in ocean conditions induced by climate change or an increase of the population is driving such an expansion of breeding areas. The GCB is an important habitat for migrating humpback whales and shows a certain plasticity regarding the whale calving habitat (Torre-Williams et al. 2019). Research within the GCB has shown that one-third of the observed pods are mother-calf pairs, with most being present in October and generally found 2 km closer to shore than are pods without calves (Valani et al. 2020). ...
Context
Humpback whales utilise coastal habitats for breeding, resting and migration where, at low latitudes, they are often exposed to vessel traffic. The Gold Coast bay (GCB) in south-eastern Queensland, Australia, is utilised by humpback whale mother–calf pairs to rest.
Aims
Identify core habitats of pods with and without calves and interception by vessel traffic in the GCB.
Method
In total, 4319 whale-sighting records from citizen science-collected data on board whale-watching vessels between 2011 and 2020 were used in this analysis. MaxEnt models were generated to determine species distribution of pods with and without calves. The distribution model was compared with automatic identification system-fitted vessel traffic available from the Australian Maritime Safety Authority over the same time to infer potential vessel impact on these sensitive cohorts.
Key results
Habitat use of pods with calves was focused on shallower areas close to shore and overlapped with the core habitat of pods without calves 5 km into the bay. Vessels intercepted up to 80% of the core habitat.
Conclusion
Vessel traffic poses a potential threat to humpback whale mother–calf pairs.
Implications
An assessment of all vessels leaving the seaway should be considered for the GCB and whale caution zones for vessel traffic.
... Movement patterns can also be influenced by a variety of intra-specific social interactions (Ersts and Rosenbaum, 2003;Craig et al., 2014) or by human activity in particular in breeding areas (Cartwright et al., 2012) making the disentanglement from environmental change drivers more complex. There is evidence of range expansion in breeding grounds as populations recover from decades of commercial whaling (Mobley et al., 1999;Johnston et al., 2007;Lammers et al., 2011) or maybe as a result of environmental changes (Torre-Williams et al., 2019). ...
... In fact, a number of studies have demonstrated that breeding behaviors have occurred outside recognized breeding grounds for HW populations (Bruce et al., 2014;Lucena et al., 2015;Irvine et al., 2018). HWs can calf every 2 years depending on feeding success (Baker and Herman, 1987;Torre-Williams et al., 2019) and the gestation period is around 12 months (Chittleborough, 1958). ...
Humpback whales, Megaptera novaeangliae, are a highly migratory species exposed to a wide range of environmental factors during their lifetime. The spatial and temporal characteristics of such factors play a significant role in determining suitable habitats for breeding, feeding and resting. The existing studies of the relationship between oceanic conditions and humpback whale ecology provide the basis for understanding impacts on this species. Here we have determined the most relevant environmental drivers identified in peer-reviewed literature published over the last four decades, and assessed the methods used to identify relationships. A total of 148 studies were extracted through an online literature search. These studies used a combined estimated 105,000 humpback whale observations over 1,216 accumulated study years investigating the relationship between humpback whales and environmental drivers in both Northern and Southern Hemispheres. Studies focusing on humpback whales in feeding areas found preferences for areas of upwelling, high chlorophyll-a concentration and frontal areas with changes in temperature, depth and currents, where prey can be found in high concentration. Preferred calving grounds were identified as shallow, warm and with slow water movement to aid the survival of calves. The few studies of migration routes have found preferences for shallow waters close to shorelines with moderate temperature and chlorophyll-a concentration. Extracting information and understanding the influence of key drivers of humpback whale behavioral modes are important for conservation, particularly in regard to expected changes of environmental conditions under climate change.
... Gestation in humpback whales typically lasts 11-12 months (Chittleborough, 1958), and in the last few weeks of pregnancy females return to low latitudes to give birth. Although parturition may occur during migration, prior to arrival in the tropics (Chittleborough, 1965;Glockner & Venus, 1983;Torre-Williams et al., 2019), it is generally believed that most humpback whales give birth in shallow coastal waters of the breeding areas. Multiple fetuses were occasionally encountered by whalers (Chittleborough, 1958), yet no record of a free-ranging humpback whale with more than one calf exists. ...
... Additionally, whaling station observations of near-term calves led Chittleborough (1958) to hypothesize that the umbilical cord breaks during parturition close to the calf's body, which is supported by stranding reports of neonates with red-raw short stumps in the umbilicus region (Groch et al., 2018). As so few births have been witnessed, the presence of neonates (both dead or alive) exhibiting these traits, can be used to identify regions used for calving and peak calving periods (Irvine et al., 2018;Torre-Williams et al., 2019). This is of great conservation importance for management purposes, especially in coastal areas which are exposed to extensive human activity. ...
Documented cases of cetacean births in the wild are rare. While there are currently no direct observations of a complete humpback whale birth, they are one of the few large whale species where observers have been present during a birthing event. We compiled eye-witnessed accounts of all known humpback whale birthing events and found nine well-documented cases globally (three published and six “new” unpublished). In two-thirds of the accounts another “escort” whale was present and in close association with the birthing female, and of these, most cases involved multiple escorts (n = 4). We describe details of birthing events, including mother, neonate and escort(s)’ behavior, neonate appearance, and discuss reasons for escort presence during parturition. We note that immediately postpartum: (1) blood and/or placenta were not always apparent during above water observations, (2) females often (but not always) supported calves at the surface, (3) constant travel and tail slapping were typical neonate behaviors, (4) two cases of temporary calf abandonment (<10 min), and (5) evidence of shark scavenging (of placenta) and possible predation attempts (of neonate). Lastly, we suggest curled tail flukes as an additional trait for identifying neonates and note that fetal folds are not always evident in newborn humpback whales.
... A humpback is classified as a calf by its close and consistent association with another whale, and with a body length < 8 m and/or < 2/3 the length of the cow [31]. Consistent with other recent studies, neonates were defined as being less than one third of their mother's body length and pale in colour [18,32,33], and appearing as described in the Introduction. A visual approximation at time of observation of the proportional body length of the calf was used to determine this classification. ...
An understanding of the spatial and temporal range of marine mammals, and identification of habitats that support critical behaviours is fundamental for effective species management and conservation. The humpback whale ( Megaptera novaeangliae ), while considered to be recovered in Australian waters, is subject to increasing levels of anthropogenic pressure across its migratory range. Historically, the Western Australian (WA) population has been known to calf in the north-west of WA in the Kimberley region (15–18° S), with recent records of calving extending as far south as Exmouth, Western Australia (21–22° S). This paper presents recent evidence of humpback whale calves being born over 1500 km further south in southwest WA (33–34° S), along their northern migratory route, including live sightings of neonates, and strandings of deceased neonate calves. The presence of neonates outside of known calving grounds presents challenges for species conservation and management with effective mitigation and management of anthropogenic pressures contingent on a contemporary understanding of species presence and behaviour. Further, there is considerable concern for the viability of calves this far south on their migratory route where water temperatures are cooler and sheltered areas for resting are more limited.
... The datasets utilised in this study, in contrast to the approach by Smith et al. (2012), extend beyond the peak breeding months of July and August. This broader temporal scope aligns with research indicating potential changes in the timing of both migration and breeding activities (Franklin et al. 2011;Ramp et al. 2015;Meynecke et al. 2017;Torre-Williams et al. 2019;Gosby et al. 2022). ...
Context
Humpback whale (Megaptera novaeangliae) populations have been recovering from whaling but are now facing threats from changing food availability due to ocean warming and changes in habitat suitability. There is uncertainty over whether opportunistic observations can produce reliable species distribution models (SDMs) and adequately inform conservation management.
Aims
To compare SDMs for humpback whales in the Great Barrier Reef Marine Park based on different opportunistic sightings datasets and evaluate the impact different sources of opportunistic data have on our understanding of humpback whale habitat relationships.
Methods
Maximum entropy modelling (Maxent) was used to create predictive models for humpback whale distributions. Sighting data from citizen science and opportunistic observations from various other databases were used. Models were compared to evaluate disparities and predictive capabilities.
Key results
Distinct environmental variables [bathymetry, distance to the coast] were identified as the most relevant for each SDM. The best-fitting model diverged from an existing model, with humpback whale distribution predicted to be closer to shore. Areas with the highest habitat suitability were concentrated in the north-eastern coastal region across all models developed in this study.
Conclusions
This study demonstrates that, with careful application and consideration, citizen science data can enhance our understanding of humpback whale distributions and contribute to their conservation. The research underlines the importance of embracing diverse data sources in SDM, despite the challenges posed by opportunistic data.
Implications
The study provides valuable insights for conservation management and informs strategies to protect humpback whale populations in changing environmental conditions.
... The bottom substrate mainly consists of sand with some rocky reefs [37]. It is an important aggregation site where humpback whales rest, socialise, and breed [38,39], within 10 km of their migratory corridor during southern and northern migrations between June and October each year [38,40]. Whales were tagged between August 2021 and October 2022 with CATS suction cup tags (https://www.cats.is, ...
Cetaceans are known for their intelligence and display of complex behaviours including object use. For example, bowhead whales (Balaena mysticetus) are known to rub on rocks and some humpback whale (Megaptera novaeangliae) populations undertake lateral bottom feeding. Such underwater behaviour is difficult to observe but can play a critical role in the whales’ survival and well-being. Distinguishing social behaviours from those which serve a specific function remains challenging due to a lack of direct observations and detailed descriptions of such behaviours. A CATS (Customized Animal Tracking Solutions) suction cup tag with on board video and a 3D inertial measurement unit was deployed on three different humpback whales to assess their behaviour in the Gold Coast bay, Australia. Here, we present evidence of humpback whales (tagged and untagged individuals) performing bottom contact with prolonged rolling on sandy substrate. In addition, we showed that fish were actively feeding from the whales’ skin during this behaviour. We detail the behaviour and discuss possible drivers, with a focus on cetacean innovation, possible ectoparasite removal, and habitat preferences.
... However, the observed changes in movement (i.e., from fast to very slow movement followed by a period of continuous movement at reduced speed) are consistent with the behavior reported from earlier observations of calving events [65,66,70]. Newborn calves have been documented outside of the described main breeding grounds elsewhere [26,71] and historical whaling records from Norway include records of late-stage pregnancies in Norwegian waters during winter and spring [72], also indicating humpback whales from this region might give birth shortly after these observations were made, likely outside breeding grounds [73]. This indicates that shallow waters are not crucial for neonates immediately after birth, but that perhaps water temperatures may need to be above some critical value [9]. ...
In the northern hemisphere, humpback whales (Megaptera novaeangliae) typically migrate between summer/autumn feeding grounds at high latitudes, and specific winter/spring breeding grounds at low latitudes. Northeast Atlantic (NEA) humpback whales for instance forage in the Barents Sea and breed either in the West Indies, or the Cape Verde Islands, undertaking the longest recorded mammalian migration (~ 9 000 km). However, in the past decade hundreds of individuals have been observed foraging on herring during the winter in fjord systems along the northern Norwegian coast, with unknown consequences to their migration phenology, breeding behavior and energy budgets. Here we present the first complete migration track (321 days, January 8th, 2019—December 6th, 2019) of a humpback whale, a pregnant female that was equipped with a satellite tag in northern Norway. We show that whales can use foraging grounds in the NEA (Barents Sea, coastal Norway, and Iceland) sequentially within the same migration cycle, foraging in the Barents Sea in summer/fall and in coastal Norway and Iceland in winter. The migration speed was fast (1.6 ms⁻¹), likely to account for the long migration distance (18 300 km) and long foraging season, but varied throughout the migration, presumably in response to the calf’s needs after its birth. The energetic cost of this migration was higher than for individuals belonging to other populations. Our results indicate that large whales can modulate their migration speed to balance foraging opportunities with migration phenology, even for the longest migrations and under the added constraint of reproduction.
... We chose the Gold Coast bay as a study site; it is a shallow open embayment located at 27 • S, 153 • E in South East Queensland, Australia ( Figure 1). The region is an important aggregation site for humpback whales located along their migratory pathway during southern and northern migrations between June and October each year [41,42]. The embayment provides shelter from the dominant southeasterly trade winds and has an average annual sea surface temperature (SST) ranging between 19.3 • C to 28 • C (https: //www.seatemperature.org/australia-pacific/australia/). ...
The study of marine mammals is greatly enhanced through fine scale data on habitat use. Here we used a commonly available asset tracker Global Positioning System/Global Systems for Mobile Communication (GPS/GSM) integrated into a CATS suction cup tag to test its feasibility in providing real time location position on migrating humpback whales in coastal waters of eastern Australia. During two deployments—one on a suspected male and another on a female humpback whale—the tags provided location points with relatively high accuracy for both individuals albeit different swim behavior and surface intervals. In combination with an integrated archival data logger, the tag also provided detailed information on fine scale habitat use such as dive profiles. However, surface intervals were too short to allow for an upload of location data during deployment. Further improvements of the tag design will allow remote access to location data after deployment. Preliminary results suggested location acquisition was better when the tag was positioned well above the midline of the whale body. The technology promises less expensive, more reliable and more accurate short-term tracking of humpback whales compared to satellite relay tags, and it has the potential to be deployed on other marine mammals in coastal waters.
... Migration for breeding occurs during winter and spring in both hemispheres (Clapham 2009). The breeding season constitutes a critical time in the life cycle of this species, and successful recruitment into the population depends on births that occur in these habitats (Torre-Williams et al. 2019). Early physical and cognitive development of calves is driven by mother and calf interactions (Faria et al. 2013, Vide -sen et al. 2017, which rely heavily on suitable habitats. ...
Humpback whales Megaptera novaeangliae are undergoing a population increase after ca. 40 yr of a whaling ban. However, anthropogenic activities threaten their recovery in recolonized breeding habitats. Predictive habitat models are important tools that can help create effective conservation measures. Due to the spatially structured distribution of this species that depends on the presence of calves and the number of individuals, models must account for specific population variability that could refine management direction. We modeled potential breeding habitats of humpback whales considering group type variability. A total of 10 yr of data (3115 sighted humpback whales from 2010 to 2019) obtained from whale-watching surveys in the breeding area of northern Peru (4°S, Southeast Tropical Pacific) were used. Maximum entropy models were constructed to predict potential habitats for breeding humpback whales considering groups with and without calves. Depth and sea surface temperature were used as descriptors for modeling the potential habitat of humpback whale groups. Depth was the main explanatory variable for all models. The optimal potential habitat for groups with calves was located between 20 and 50 m depth. Groups without calves ranged more widely in habitat, from 20 to 100 m depth. The predictive character of these models shows segregated potential habitats of breeding humpback whales, which could help refine conservation actions. For example, limiting the number of whale-watching boats in nearshore waters when mother and calf pairs are present would reduce conflict, while restricting the use of gillnets in transitional neritic to oceanic waters is mandatory to mitigate entanglements.
... The location of the current study (27 °S) places our whale population within 12 to 24 days travel from the typical calving grounds, extending between 21° and 15° S 37 . However, both east and west Australian HW births have been shown to occur over a wider latitudinal range than previously identified 38,39 . The recent recognition of South-East Queensland as a suitable calving ground for HWs suggests that the current study might include females rapidly approaching parturition. ...
The blubber steroid hormone profiles of 52 female humpback whales migrating along the east coast of Australia were investigated for seasonal endocrine changes associated with reproduction. Individuals were randomly sampled during two stages of the annual migration: before reaching the breeding grounds (northward migration; June/July), and after departing from the breeding grounds (southward migration; September/October). Assignment of reproductive status of the sampled individuals was based on season, single-hormone ranks and multi-variate analysis of the hormonal profiles. High concentrations of progesterone (>19 ng/g, wet weight), recognised as an indicator of pregnancy in this species, were only detected in one sample. However, the androgens, testosterone and androstenedione were measured in unusually high concentrations (1.6–12 and 7.8–40 ng/g wet weight, respectively) in 36% of the females approaching the breeding grounds. The absence of a strong accompanying progesterone signal in these animals raises the possibility of progesterone withdrawal prior to parturition. As seen with other cetacean species, testosterone and androstenedione could be markers of near-term pregnancy in humpback whales. Confirmation of these androgens as alternate biomarkers of near-term pregnancy would carry implications for improved monitoring of the annual fecundity of humpback whales via non-lethal and minimally invasive methods.
The spatial distribution of calving habitat of humpback whales (Megaptera novaeangliae) has been understood as confined to warm, low latitude waters. The need for females to reach such habitats to give birth and provide early maternal care underpins the dominant theories on humpback whale migration. In Australia, calving habitat is accepted to be distributed no further south than 23-28°S and is generally presumed not to occur in New Zealand. The aim of this study was to understand if humpback whales birth beyond these limits and, if so, whether cow-calf pairs continue migrating northward. Records of neonate calves were collated from several sources, including government agencies, annual migration surveys and opportunistic citizen science observations, primarily from tourism vessels. Strict inclusion protocols were applied to ensure correct identification of calves as neonates. More than 200 neonates were recorded in all jurisdictions in the study area, to 43°S, approximately 1300 – 1500 km south of the previously reported southern limit of calving grounds in Australasia. These records demonstrate that humpback whales do not confine their calving solely to tropical zones but exhibit a continuum of habitat use throughout their range. The cow-calf pairs were consistently observed to continue northward in Eastern Australia and New Zealand, suggesting that birth does not define the endpoint of the migration. There are management implications of these findings as currently some jurisdictions are not recognized as calving habitats. Therefore, the revision of protection measures in these areas given the new evidence of extended calving habitat would assist in reducing anthropogenic threats to young calves during vulnerable life stages. Additionally, the continuation of northward migration after birth of the calf is an important observation for migration theory. Future studies comparing the outcomes for calves born during migration with those born in the tropical wintering grounds could provide empirical information to evaluate hypotheses on the drivers of migration. The results of this study challenge prevailing notions of calving and migration behavior in this species.
Humpback whales Megaptera novaeangliae encounter a variety of environmental conditions during seasonal migration between feeding grounds and breeding grounds. Relationships between environmental conditions and migratory movements are largely unknown due to a lack of oceanographic data coincident with their presence/absence. We begin to address this knowledge gap by developing a new agent‐based modelling (ABM) approach designed to predict southward migration of mother–calf (MC) pairs along a stretch of the east Australian coast between the Great Barrier Reef (GBR) and Gold Coast (GC) bay, which includes a known resting area, Hervey Bay (HB). To assess our ability to reproduce observed migration patterns, numerical experiments were undertaken in which static (bathymetry) and dynamic (currents, sea surface temperature) variables between August and October 2017 governed movements. These experiments revealed how bathymetry influences HB usage, and a necessity to apply different directionality preferences to whales before and after negotiating HB, which appear to closely align with coastline orientation. The ABM provides a novel, suitable framework for simulating MC humpback whale migration, and an important first step in the development of predictive models of humpback whale behavior. Developing such tools is increasingly necessary to predict how changing ocean conditions are likely to affect their distribution.
Southern Hemisphere humpback whales (Megaptera novaeangliae) were heavily targeted during modern commercial whaling operations, with some 216,000 individuals killed between 1903 and 1973. That impacted the abundance of all the seven breeding stocks of the species. Most of these stocks have been recovering from whaling pressure although the understanding of the current growth rates of some stocks, and how the rates compare across stocks are lacking. Updated information is fundamental for understanding the species’ current status, and to support the review of management plans promoting its protection and recovery, especially considering current changes in ocean environments due to climate change. This work offers a comprehensive overview of the current knowledge on Southern Hemisphere humpback whales breeding stocks’ status. The aim is to provide information on their post-whaling growth trends and changes in distribution and migration patterns. Within that, records of supplementary feeding records (i.e. feeding beyond their formally described feeding grounds) are described. We have also identified knowledge gaps and note that the establishment of research collaborations, as well as standard methodologies for data collection can be important steps for the acquisition of better comparable data sets for the analysis of the current status of humpback whales and to fill such gaps. The compiled information provided can be used as part of an In-Depth Assessment of the species by the International Whaling Commission.
Migratory humpback whales ( Megaptera novaeangliae ) cover the cost of reproduction in low‐latitude breeding grounds with stored energy accumulated from polar feeding grounds. The ability to accumulate sufficient energy reserves during feeding periods is vital for key life history stages during migration, including mating, calving, and lactation. This study aimed to investigate the relationship between migration timing and body condition of Western Australian humpback whales. We used unmanned aerial vehicles to measure body condition (residual of body volume vs. length) in 2017 and 2021. Morphometric measurements were obtained from 460 individuals (71 calves, 83 juveniles, 235 adults, and 71 lactating females) during the northbound (toward breeding grounds) and southbound (toward feeding grounds) migration between May and November. Body condition decreased by 23 and 13 percentage points for juveniles and adults, respectively. The body condition of juveniles was shown to be correlated with migration timing for their northern migration, with individuals in better body condition migrating to the breeding grounds earlier. While stored energy is vital for humpback whales to successfully complete their vast migration to‐and‐from breeding grounds, we found no evidence that body condition affects the migration timing for adults, lactating females, and calves.
Le whale whatching, est une activité écotouristique qui consiste à observer des baleines dans leur milieu naturel. Aujourd’hui, le tourisme baleinier est pratiqué dans 119 pays et représente une véritable industrie, générant plus de deux milliards de dollars US dans le monde. À La Réunion, l’augmentation du nombre de baleines à bosse (Megaptera novaeangliae) observées a permis l’implantation de ce tourisme il y a une quinzaine d’année. Les îles situées dans la zone bénéficient d’une importante opportunité économique en développant ce secteur. Dans ce présent travail, nous cherchons à déterminer la structure du tourisme baleinier à La Réunion ainsi que l’opinion des touristes et des Réunionnais concernant cette activité. Pour ce faire, nous avons retracé d’abord l’évolution historique des relations Humains-Baleines et la représentation vis-à-vis des baleines à l’échelle internationale. Ensuite, nous avons étudié la croissance et les caractéristiques de ce secteur à Madagascar et l’île Maurice dans le but de comparer ces résultats avec ceux de La Réunion. Afin d’identifier le profil général des participants du whale watching à La Réunion, une enquête quantitative sous forme de questionnaires a été effectuée auprès de différents opérateurs. En essayant de comprendre plus profondément l’opinion des pratiquants et des non-pratiquants de cette activité, nous avons mené des entretiens semi-directifs. Sur l’île Sainte-Marie (Madagascar), où le Festival des Baleine est dédié à cet animal, à la culture locale et au whale watching, nous avons conduit une série d’entretiens semi-directifs avec les touristes. Nous avons tenté d’identifier leurs représentations du tourisme des cétacés. Par ce travail, nous apportons des premiers éléments de réponses sur le type de participants et leur perception du whale watching dans le sud-ouest de l’océan Indien.
The Gold Coast bay in eastern Australia has been hypothesised to be an important habitat, primarily for humpback whale (Megaptera novaeangliae) mother-calf pairs. Here we investigated relative distribution , and temporal patterns from 2,305 humpback whales between 2011 to 2017. The data were collected from whale-watching vessels using citizen science. We analysed seasonal presence of mother-calf pairs, dive times, direction of movement and location to determine habitat use of the bay as aresting area. In average aquarter of all sighted whales were mother-calf pairs with peaks of sightings each October. The recorded average dive time of 3.20 minutes was short compared to that in migratory corridors. Mother-calf pairs were sighted more often closer to shore relative to other pods. We compared our results to recognised breeding and resting grounds and found similar results, indicating that the Gold Coast bay may serve as an important stopover for humpback whale mother-calf pairs. ARTICLE HISTORY
Humpback whales (Megaptera novaeangliae) are known for their nearshore distribution during the breeding season, but their pelagic habitat use patterns remain mostly unexplored. From 2016 to 2018, 18 humpback whales were equipped with depth-recording satellite tags (SPLASH10) to shed light on environmental and social drivers of seamount association around New Caledonia in the western South Pacific. Movement paths were spatially structured around shallow seamounts (<200 m). Indeed, two males stopped over the Lord Howe seamount chain during the first-ever recorded longitudinal transit between New Caledonia and the east coast of Australia. Residence time significantly increased with proximity to shallow seamounts, while dive depth increased in the vicinity of seafloor ridges. Most of the 7,986 recorded dives occurred above 80 m (88.5%), but deep dives (>80 m, max 616 m) were also recorded (11.5%), including by maternal females. Deep dives often occurred in series and were characterized by U-shapes suggesting high energy expenditure. This study provides new insights into the formerly overlooked use of pelagic habitats by humpback whales during the breeding season. Given increasing anthropogenic threats on deep sea habitats worldwide, this work has implications for the conservation of vulnerable marine ecosystems.
In the context of a changing climate, understanding the environmental drivers of marine megafauna distribution is important for conservation success. The extent of humpback whale breeding habitats and the impact of temperature variation on their availability are both unknown. We used 19 years of dedicated survey data from seven countries and territories of Oceania (1,376 survey days), to investigate humpback whale breeding habitat diversity and adaptability to climate change. At a fine scale (1 km resolution), seabed topography was identified as an important influence on humpback whale distribution. The shallowest waters close to shore or in lagoons were favored, although humpback whales also showed flexible habitat use patterns with respect to shallow offshore features such as seamounts. At a coarse scale (1° resolution), humpback whale breeding habitats in Oceania spanned a thermal range of 22.3–27.8°C in August, with interannual variation up to 2.0°C. Within this range, both fine and coarse scale analyses of humpback whale distribution suggested local responses to temperature. Notably, the most detailed dataset was available from New Caledonia (774 survey days, 1996–2017), where encounter rates showed a negative relationship to sea surface temperature, but were not related to the El Niño Southern Oscillation or the Antarctic Oscillation from previous summer, a proxy for feeding conditions that may impact breeding patterns. Many breeding sites that are currently occupied are predicted to become unsuitably warm for this species (>28°C) by the end of the 21st century. Based on modeled ecological relationships, there are suitable habitats for relocation in archipelagos and seamounts of southern Oceania. Although distribution shifts might be restrained by philopatry, the apparent plasticity of humpback whale habitat use patterns and the extent of suitable habitats support an adaptive capacity to ocean warming in Oceania breeding grounds.
Integrating behavior and physiology is critical to formulating new hypotheses on the evolution of animal life-history strategies. Migratory capital breeders acquire most of the energy they need to sustain migration, gestation, and lactation before parturition. Therefore, when predicting the impact of environmental variation on such species, a mechanistic understanding of the physiology of their migratory behavior is required. Using baleen whales as a model system, we developed a dynamic state variable model that captures the interplay among behavioral decisions, energy, reproductive needs, and the environment. We applied the framework to blue whales (Balaenoptera musculus) in the eastern North Pacific Ocean and explored the effects of environmental and anthropogenic perturbations on female reproductive success. We demonstrate the emergence of migration to track prey resources, enabling us to quantify the trade-offs among capital breeding, body condition, and metabolic expenses. We predict that periodic climatic oscillations affect reproductive success less than unprecedented environmental changes do. The effect of localized, acute anthropogenic impacts depended on whales’ behavioral response to the disturbance; chronic, but weaker, disturbances had little effect on reproductive success. Because we link behavior and vital rates by modeling individuals’ energetic budgets, we provide a general framework to investigate the ecology of migration and assess the population consequences of disturbance, while identifying critical knowledge gaps.
We investigated whether calf age and calf size influence habitat choice by humpback whale mother-calf pairs in their breeding grounds. During 1997-2008, we conducted focal follows of mother-calf pairs in Hawaiian waters. Tail-fluke identification photographs and calf lengths (measured through videogrammetry) were obtained. Water depth and sea-bed terrain type were derived from GPS data. Identification photographs were matched so that the habitat choices could be established within breeding seasons. Across 72 mother-calf pairs resighted over various intervals within a breeding season, magnitude of depth change between initial and final sightings increased significantly with resighting interval. There was a significant increase from initial depth to final depth for relatively long resighting intervals (27-51 days), but no significant difference for relatively short resighting intervals (2-26 days). Although there was no preference for sea-bed terrain type by motherecalf pairs at their initial sighting, there was a preference for rugged terrain at their final resighting. A resource selection model indicated that the relative probability of a location being used by a motherecalf pair increased (as a function of water depth and rugged sea-bed terrain type) from initial to final sighting; a finding supported by subsequent tests of habitat preference versus availability. For 96 measured calves, calf length and water depth were positively correlated, even when ordinal day of measurement was controlled for statistically; a finding confirmed by a general linear model that simultaneously investigated the relationship between water depth, sea-bed terrain type, number of escorts, ordinal day and calf size. Thus, both calf age and size influence habitat choice by mother-calf pairs in their breeding grounds. The movement of mothers and their maturing calves into deeper waters where they favour rugged sea-bed terrain appears to be part of a suite of behavioural changes during the pre-migratory phase of residency in the breeding grounds.
The western South Atlantic humpback whale Megaptera novaeangliae population was severely depleted by commercial whaling in the late 19th and 20th centuries, and today inhabits a human-impacted environment in its wintering grounds off the Brazilian coast. We identified distribution patterns related to environmental features and provide new estimates of population size, which can inform future management actions. We fitted spatial models to line transect data from 2 research cruises conducted in 2008 and 2012 to investigate (1) habitat use and (2) abundance of humpback whales wintering on the Brazilian continental shelf. Potential explanatory variables were year, depth, seabed slope, sea-surface temperature (SST), northing and easting, current speed, wind speed, distance to the coastline and to the continental shelf break, and shelter (a combination of wind speed and SST categories). Whale density was higher in slower currents, at shorter distances to both the coastline and shelf break, and at SSTs between 24 and 25°C. The distribution of whales was also strongly related to shelter. For abundance estimation, easting and northing were included in the model instead of SST; estimates were 14 264 whales (CV = 0.084) for 2008 and 20 389 (CV = 0.071) for 2012. Environmental variables explained well the variation in whale density; higher density was found to the south of the Abrolhos Archipelago, and shelter seems to be important for these animals in their breeding area. Estimated distribution patterns presented here can be used to mitigate potential human-related impacts, such as supporting protection in the population’s core habitat near the Abrolhos Archipelago.
Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll- a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.
The complex influences of the East Australian Current (EAC) and winds on the waters of the continental shelf were addressed with a ship survey, moored and drifting instruments, satellite images and wind and sea level measurements. The study revealed intrusions of continental slope water reaching the inner continental shelf when the EAC was near the shelf edge and wind stress was near zero or upwelling favourable (northerly). The process was the onshore movement of a southward flowing stream of water originally from the continental slope. One event was captured near Cape Byron and Evans Head when these waters upwelled to the surface. When the wind stress turned northward, it reversed the inner shelf current and drove downwelling. Variations in the wind stress also modulated the strength of the EAC out across the shelf to the upper slope. The strength of the EAC per se varied with a time scale of 2–3 months; these variations decreased in amplitude westward until they were undetectable at the inner shelf. The EAC had a subsurface speed maximum of up to 1.6 m s–1 at 100–150-m depth above the continental slope and was seen to accelerate with both time and distance southward along the 190-km length surveyed by the ship.
Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll-a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.
Understanding the distribution, habitat preference, and social structure of highly migratory species at important life history stages (e.g., breeding and calving) is essential for conservation efforts. We investigated the spatial distribution and habitat preference of humpback whale social groups and singers, in relation to depth categories (<20 m, 20-50 m, and >50 m) and substrate type (muddy and mixed) on a coastal southeastern Pacific breeding ground. One hundred and forty-three acoustic stations and 304 visual sightings were made at the breeding ground off the coast of Esmeraldas, Ecuador. Spatial autocorrelation analysis suggested singers were not randomly distributed, and Neu's method and Monte Carlo simulations indicated that singers frequented depths of <20 m and mixed substrate. Singletons, and groups with a calf displayed a preference for shallower waters (0-20 m), while pairs and groups with a calf primarily inhabited mixed bottom substrates. In contrast, competitive groups showed no clear habitat preference and exhibited social segregation from other whales. Understanding the habitat preference and distribution of humpback whales on breeding and calving grounds vulnerable to anthropogenic disturbance provides important baseline information that should be incorporated into conservation efforts at a regional scale.
Taking a fresh look at Darwin’s original theory of the origin of species and following the road paved by Gause, Hutchinson, MacArthur, and Levins a consistent system of fundamental principles is revealed, one that makes the integration of ecology possible. These principles are explained, formalized, and illustrated by mutually compatible mathematical models in this book, demonstrating how this coherent modelling approach helps to explain or predict actual population and community dynamics and patterns on the field or in the lab. At the core of the Darwinian theory of ecology lies a generalized fitness concept applicable to populations of alleles and clones as well as of conspecific individuals. It is the theory of structured populations that provides a universal methodology to calculate the fitness of any reproductive unit in the face of any complexity arising from differences in individual states. The inherent capacity of all living organisms to increase their populations exponentially is necessarily constrained by resource depletion or natural enemies, so that the ultimate growth rate of persistent populations is regulated. Competition between different reproductive units leads either to competitive exclusion or to robust coexistence, depending on how similarly they are regulated. This is shown in general and demonstrated with several types of models. A generalized and formalized niche theory consistent with the principles is explicated, discussed, and illustrated by empirical studies. Studies on global, regional, and local ecological patterns close the book, discussed in the spirit of the process-based approach of Darwinian ecology.
keywords: ecological principles, reproductive units, fitness, exponential growth, population regulation
niche theory, coexistence, competitive exclusion, process-based ecology, ecological models
Climate change is driving changes in the physical and chemical properties of the ocean that have consequences for marine ecosystems. Here, we review evidence for the responses of marine life to recent climate change across ocean regions, from tropical seas to polar oceans. We consider observed changes in calcification rates, demography, abundance, distribution, and phenology of marine species. We draw on a database of observed climate change impacts on marine species, supplemented with evidence in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We discuss factors that limit or facilitate species' responses, such as fishing pressure, the availability of prey, habitat, light and other resources, and dispersal by ocean currents. We find that general trends in species' responses are consistent with expectations from climate change, including shifts in distribution to higher latitudes and to deeper locations, advances in spring phenology, declines in calcification, and increases in the abundance of warm-water species. The volume and type of evidence associated with species responses to climate change is variable across ocean regions and taxonomic groups, with predominance of evidence derived from the heavily-studied north Atlantic Ocean. Most investigations of the impact of climate change being associated with the impacts of changing temperature, with few observations of effects of changing oxygen, wave climate, precipitation (coastal waters), or ocean acidification. Observations of species responses that have been linked to anthropogenic climate change are widespread, but are still lacking for some taxonomic groups (e.g., phytoplankton, benthic invertebrates, marine mammals).
Fifty animals were identified in 1986, 40 in 1987 and 35 in 1988 for a total of 108. Eleven individuals were common to 1986/1987 and size to 1987/1988. Three individuals were common for the three years. Estimates of the population for the 3 yr ranged from 170-450. The importance of Gorgona as a calving area is shown by the fact that 26.5% of animals were calves. -from Author
The humpback whale population of New Caledonia appears to display a novel migratory pattern characterized by multiple directions, long migratory paths and frequent pauses over seamounts and other shallow geographical features. Using satellite-monitored radio tags, we tracked 34 whales for between 5 and 110 days, travelling between 270 and 8540 km on their southward migration from a breeding ground in southern New Caledonia. Mean migration speed was 3.53±2.22 km h(-1), while movements within the breeding ground averaged 2.01±1.63 km h(-1). The tag data demonstrate that seamounts play an important role as offshore habitats for this species. Whales displayed an intensive use of oceanic seamounts both in the breeding season and on migration. Seamounts probably serve multiple and important roles as breeding locations, resting areas, navigational landmarks or even supplemental feeding grounds for this species, which can be viewed as a transient component of the seamount communities. Satellite telemetry suggests that seamounts represent an overlooked cryptic habitat for the species. The frequent use by humpback whales of such remote locations has important implications for conservation and management.
As part of a long-term population study of humpback whales breeding on the coast of Ecuador (2°S, 81°W), four sites on the central coast were surveyed: Puerto Cayo, Puerto López, La Plata Island and Salinas. The spatial, temporal and age class distributions of 322 groups positioned during the period of 1996-2003 were analysed regarding their distance from the shore and water depth with two statistical methods: one-way ANOVA and linear modelling. The average sighting distance from shore varied between 5.31km in Salinas and 10.16km in Puerto Cayo with mid values in Puerto López and La Plata Island. Average water depth was similar in Puerto López, La Plata Island and Salinas (36-39m) but lower in Puerto Cayo (19.43m). Differences were highly significant in both cases (p<0.01). A progressive but not significant increase in the average distance from shore was found (6.2km in June to 7.17km in September). Sighting depth was constant between June and August (average 35-36m) but decreased significantly in September to 27m (p<0.01). This difference was attributed to the presence of mother-calf pairs in shallower water by the end of the season. Age class analyses using ANOVA showed highly significant differences between groups of adults, and adults with subadults with respect to singleton subadults, and groups containing a mother-calf pair for both distance from shore and depth (p<0.01); however, linear modelling analyses showed only depth was significant (p=0.026). This suggests that depth is a more important determinant of differences in distribution between these age classes than proximity to shore. The sightings distribution showed segregation of both mother-calf pairs (towards shallow waters) and of singleton subadults (towards the boundaries of the surveyed area). Since only eight sightings (2.5%) were in waters deeper than 60m, we propose that depth is a major feature determining humpback whale distribution in these waters. Implications of this coastal distribution are discussed, particularly with respect to bycatch in fishing gear and whalewatching. A review of recent southeast Pacific sightings showed that humpback whales are also abundant in coastal waters to the southwest of Ecuador (3°S) and confirmed that they are scarce offshore. However, whales are more widely distributed in the north of Peru (4°-6°S) where they make the transition between deeper oceanic and shallower coastal waters when arriving at and leaving the breeding area.
This paper presents an analysis of the migration movements of Southeast Pacific humpback whales (Megaptera novaeangliae) based on satellite and sighting data. We used information obtained from six humpback whales tagged off the coast of Ecuador between August and September 2013, and sighting information from oceanographic cruises and seismic prospection studies. Tagged humpback whales were followed along the west coast of South America, and in one case off the Antarctic Peninsula, for between 11 and 72 d. Distance covered by tracked whales was between 920 and 8,670 km. While available sighting data indicated that humpback whales follow a coastal route, satellite tracking data show that single adults use a more direct offshore route and mother/calf pairs tend to follow the longer coastal route. A 4-d period of irregular movements by a mother with a calf off central Peru suggested foraging behavior in this area characterized by intense upwelling processes. On the other hand, the humpback whale that reached Antarctic waters by mid-October quickly moved 200 km off the Antarctic Peninsula, probably because the zone was still covered by ice. We also found differences in travel speed between age/sex classes of humpback whales with mother/calf pairs traveling about 30% slower than single adults. The average humpback whale swim speed ranged between 65.5 and 169 km.d-1. Our information provides a first examination of potential routes used by this whale population and highlights the need for a regional approach in appropriately addressing the migratory behavior and threats to the species during its annual migration.
ePublications@SCU is an electronic repository administered by Southern Cross University Library. Its goal is to capture and preserve the intellectual output of Southern Cross University authors and researchers, and to increase visibility and impact through open access to researchers around the world. For further information please contact epubs@scu.edu.au. Publication details Franklin, W 2014, ' Abundance, population dynamics, reproduction, rates of population increase and migration linkages of eastern Australian humpback whales (Megaptera novaeangliae) utilising Hervey Bay, Queensland', PhD Thesis,
During the winter months, from June to September, humpback whales Megaptera novaeangliae breed and calve in the waters of the Great Barrier Reef (GBR) after migrating north from Antarctic waters. Clearly defined wintering areas for breeding and calving comparable to those identified in other parts of the world have not yet been identified for humpback whales in the GBR Marine Park (GBRMP), mainly because of its large size, which prohibits broad-scale surveys. To identify important wintering areas in the GBRMP, we developed a predictive spatial habitat model using the Maxent modelling method and presence-only sighting data from non-dedicated aerial surveys. The model was further validated using a small independent satellite tag data set of 12 whales migrating north into the GBR. The model identified restricted ranges in water depth (30 to 58 m, highest probability 49 m) and sea surface temperature (21 to 23 degrees C, highest probability 21.8 degrees C) and identified 2 core areas of higher probability of whale occurrence in the GBRMP, which correspond well with the movements of satellite tagged whales. We propose that one of the identified core areas is a potentially important wintering area for humpback whales and the other a migration route. With an estimated increase in port and coastal development and shipping activity in the GBRMP and a rapidly increasing population of whales recovering from whaling off the east Australian coast, the rate of human interactions with whales is likely to increase. Identifying important areas for breeding and calving is essential for the future management of human interactions with breeding humpback whales.
quite plausible) intrinsic rates of increase for each popu-lation. In the modeling scenarios, the demand for immi-grants would eventually exceed the supply and exhaust the source population, but the simulations demonstrated that high increase rates can be sustained over periods of more than 20 years. This hypothesis, if correct, would not only explain excessively high rates of increase in current " hot-spots " such as eastern Australia, but also imply that for-merly important areas (e.g., Fiji) host few whales today not necessarily because of a failure to recover, but because the species' mating system leads the whales concerned to migrate to higher-density breeding grounds elsewhere. Overall, we caution that assessments of depleted animal populations that do not consider the social behavior of a species are missing a potentially vital component of the picture.
Data on distribution and behaviour of mother-calf pairs of humpback whales Megaptera novaeangliae obtained during the breeding season (June to October) off Ecuador were analysed. The study was carried out between 2001 and 2009 aboard whale-watching boats. A total of 187 groups containing mother-calf pairs were recorded: 124 pairs alone (MC), 44 with an escort whale (MCE) and 18 with 2 or more whales (MC + n). Five environmental variables were used to assess mother-calf distribution with a principal component analysis (PCA). Two variables, depth and time of day, were sufficient to explain heterogeneity. Average depths increased significantly with group size from MC to MC + n groups (p < 0.001), showing that mother-calf social condition would be a function of the depth at which they moved. MC groups were distributed in shallower waters during afternoon hours (p = 0.035), indicating a preference for shelter areas when sea conditions worsened. The proportion of the 3 female-calf group classes remained fairly constant during the season. In 2 MCE groups, the same escort accompanied the pair after 1 and 4 d, indicating some level of stability and/or guarding behaviour. Twenty resightings of 14 different mother-calf groups were recorded, 90% of resightings occurred within 10 d, showing low site fidelity. In coastal waters, a lower proportion of mother-calf pairs was associated with competitive groups than in other breeding areas located in oceanic archipelagos. This is probably because whales breeding in continental shores do not have to enter oceanic waters when moving between sites within the breeding area. Coastal distribution exposes mother-calf pairs to a greater extent than other age classes to anthropogenic activities in coastal waters, which must be taken into account when considering coastal management.
Reports of killer whales (Orcinus orca) preying on large whales have been relatively rare, and the ecological significance of these attacks is controversial. Here we report on numerous observations of killer whales preying on neonate humpback whales (Megaptera novaeangliae) off Western Australia (WA) based on reports we compiled and our own observations. Attacking killer whales included at least 19 individuals from three stable social groupings in a highly connected local population; 22 separate attacks with known outcomes resulted in at least 14 (64%) kills of humpback calves. We satellite-tagged an adult female killer whale and followed her group on the water for 20.3 h over six separate days. During that time, they attacked eight humpback calves, and from the seven known outcomes, at least three calves (43%) were killed. Overall, our observations suggest that humpback calves are a predictable, plentiful, and readily taken prey source for killer whales and scavenging sharks off WA for at least 5 mo/yr. Humpback “escorts” vigorously assisted mothers in protecting their calves from attacking killer whales (and a white shark, Carcharodon carcharias). This expands the purported role of escorts in humpback whale social interactions, although it is not clear how this behavior is adaptive for the escorts.
Oral J-ristory intewiews indicate that humpback whales used to winter in Great Barrier Reef waters in such numbers that they were considered a hazard .to fishing, and that numbers declined dramltically coincident with whaling on the east coast of Australia in the 1950's and larly 1960's. Anecdotal evidence suggests a recent increase in whale sightings in reef waters as well as at the latitudes of the former shore statio"ns. Tlese data s.ugge"t that most of the humpbacks which migrate along the east coast of Australia, winter in the Greit Barrier Reef lagoon. Relent sightings of humpbacks tend to reflect human ,r-sag-9 of thi region. rr, ,...rn years, they have been sigtrted near ma-.ty reefs,'lshnds and iilshore areas, however, winter concentrations comparable to those seen in some "ttt.r pr.ts of the world have not been reported. This probably reflecrs both the vastness of the area and the low whlle numbers.'Calves have been seen at many places in the Great Barrier Reef lagoon. Some females "pp"...,ity ."r* before they reach reef waters. Hump6acks have also been sigtried ,r.r', th. northern end of the Great Barrier Reef (10"31' S) between October and January after the end of the main north-south mlgration.
Discovery mark tagging provided the first evidence of linkages between eastern Australian and Oceania Humpback whale breeding grounds and the Antarctic Area V feeding areas. Early investigation of movements of humpback whales in the Western Pacific led to the view that the Balleny Islands and the Ross Sea were the summer destinations for humpback whales from eastern Australia and the Oceania breeding grounds. Recent photo-identification (ID) studies provided further evidence of low levels of migratory interchange and complex linkages within Oceania and between eastern Australia and Oceania. We report here the migratory movement of three humpback whales (Megaptera novaeangliae) between Eastern Australia (E(i) breeding stock) and the Area V Antarctic feeding area in the vicinity of the Balleny Islands. Using photo-ID techniques, comparisons between a Balleny Island fluke catalogue (n = 11 individuals) and existing fluke catalogues from eastern Australia (n = 3,120 individuals) and Oceania (n = 725 individuals), yielded three matches to Hervey Bay, Byron Bay and Ballina in eastern Australia and no matches to Oceania. The eastern Australia catalogue (n = 3,120) was made up of Hervey Bay (n = 1,556), Byron Bay, (n = 916) and Ballina (n = 648). The Oceania catalogue (n = 725) is made up of Tonga (n = 282); New Caledonia (n = 160); French Polynesia (n = 159); New Zealand (n = 41); Cook Islands (n = 36); American Samoa (n = 31); Vanuatu, Niue, Samoa and Fiji (n = 11) and Norfolk Island (n = 5). Only three previous individual photo-ID matches have been reported between eastern Australia Breeding Stock E(i) and Antarctic Area V feeding areas in the vicinity of the Balleny Islands and the Ross Sea. Only one genotype match has been reported between Antarctic Area V feeding areas and Oceania breeding grounds. An analysis of the frequencies of whales seen and not seen in the Balleny Islands, Oceania and eastern Australia, relative to the expected frequencies, based on the estimated population sizes and the sizes of the catalogues, supports the hypothesis that Antarctic Area V waters, in the vicinity of the Balleny islands, is a summer feeding area for some eastern Australian humpback whales.
Humpback whales (Megaptera novaeangliae) feed at high latitudes and migrate to low latitudes to breed. During the austral winter, humpback whales from the C-stock population migrate from their feeding ground in Antarctica to breeding grounds in the Indian Ocean (Rosenbaum et al., 1997). The C3 subpopulation was estimated to be 2,532 indi-viduals in 1994 (Reilly et al., 2008), and between 4,936 and 8,169 in 2009 (Reilly et al., 2008). Humpback whales conceive during the wintering months or en route and have a gestation period of 11 to 12 mo (Craig et al., 2003). The coastal waters of Sainte Marie, an island off the northeast coast of Madagascar, are a well-known calving and breed-ing ground for this humpback whale subpopulation (Cartwright & Sullivan, 2009). We report a sighting of a humpback whale birth in the southern waters of Ste Marie Island that took place on 30August 2010. Observations and documented records of ceta-ceans’ births are scarce; so far, births of six ceta-cean species have been reported in the wild: the killer whale (Orcinus orca) (Jacobsen, 1981; Stacy & Baird, 1997), sperm whale (Physeter macro-cephalus)(Weilgart & Whitehead, 1986), beluga (Delphinapterus leucas) (Beland et al., 1990), false killer whale (Pseudorca crassidens) (Notarbartolo diSciara et al., 1997), right whale (Eubalaena glaci-alis) (Zani et al., 2008), and gray whale (Eschrichtius robustus) (Balcomb, 1974; Leatherwood & Beach, 1975; Mills & Mills, 1979). However, no observa-tions of humpback whale births have been docu-mented and very little is known about newborns and the behaviours associated with birth, despite the fact that this species is widely studied. This is the first account of a humpback whale birth observation and the paper will deal with two main aspects: (1) the behaviour of the escorts and the mother before, during, and after the birth; and (2) the morphology and behaviour of the newborn.The birth event was observed from a small whale-watching vessel (8 m long) within a 2km radius off the southwest coast of Ste Marie Island where the water depth ranged between 20 to 50 m (Figure 1). The behaviour of the group comprising the mother and the newborn was recorded adopting focal follow sampling techniques, noting the GPS locations and time of encounters (Altmann, 1974). The humpback whales encountered during the birthing event were arbitrarily assigned the follow-ing lettering for ease of description: the nuclear animal (female whale) was named NA; the primary escort whale, PE; the secondary escort whale, SE; and the other escorts (challengers C) were assigned letters in alphabetical order commencing with D according to their relative place in the group. The mother was defined by her proximity to the calf. A calf is defined as an individual having 1⁄3 to 1⁄2 of the total length of its mother (Tyack & Whitehead, 1983; Spitz et al., 2002).
On a global scale, false killer whales (Pseudorca crassidens) remain one of the lesser known
delphinids. The occurrence, site fidelity, association patterns, and presence/
absence of foraging in waters off northeastern New Zealand are examined from
records collected between 1995 and 2012. The species was rarely encountered; however,
of the 61 distinctive, photo-identified individuals, 88.5% were resighted, with
resightings up to 7 yr after initial identification, and movements as far as 650 km
documented. Group sizes ranged from 20 to ca. 150. Results indicate that all individuals
are linked in a single social network. Most observations were recorded in
shallow (<100 m) nearshore waters. Occurrence in these continental shelf waters is
likely seasonal, coinciding with the shoreward flooding of a warm current. During
91.5% of encounters, close interspecific associations with common bottlenose dolphins
(Tursiops truncatus) were observed. Photo-identification reveals repeat inter- and
intraspecific associations among individuals with 34.2% of common bottlenose
dolphins resighted together with false killer whales over 1,832 d. While foraging
was observed during 39.5% of mixed-species encounters, results suggest that social
and antipredatory factors may also play a role in the formation of these mixed-species
groups.
In the austral winter of July 2004, off southeast- ern Queensland, Australia, we observed apparent feeding by an adult humpback whale (Megaptera novaeangliae) in association with Indo-Pacific bottlenose dolphins (Tursiops aduncus). This is the first documented case of an adult humpback whale from the southern hemisphere Group V stock feeding along the migratory corridor. This observation also represents the first published record of a humpback whale feeding in associa- tion with Indo-Pacific bottlenose dolphins.
The abundance of east Australian Group V substock (EAGVS) humpback whales resident during winter in Hervey Bay was estimated from a 10 yr mark-resight study using photo-identification of 969 individual humpbacks sighted between 1987 and 1996. Hervey Bay is on the east coast of Australia and is the major southbound stop-over site for humpbacks returning to Antarctic waters from overwintering in Great Barrier Reef (GBR) waters. Seasonal abundance estimates were derived from mark-resight profiles using a reduced form Cormack-Jolly-Seber (CJS) model (constant survival, time-varying resight likelihood) that fitted the data well. The bootstrap mean CJS abundance estimate over the 9 yr period from 1988 to 1996 was 855 (95% CI: 750 to 936). Estimated humpback abundance m Hervey Bay showed significant temporal variability superimposed on an increasing linear trend estimated using times series regression model bootstrapping at 6.3 % yr-1 (95 % CI: 2 to 11%). The seasonal Hervey Bay population comprised 30 to 50 % of the EAGVS southbound to Antarctic feeding grounds. Estimated abundance increased from 554 post-yearling humpbacks in 1988 to a peak of 1040 in 1991 before declining to 921 by the mid-1990s. Standard errors of abundance estimates suggested good precision and were derived using a variance components approach that separated sampling error from ecologically relevant variation. The trends in temporal variability and annual rate of humpback abundance increase were consistent with findings from an aerial surveillance study (1982 to 1996) of monthly sightings of the EAGVS overwintering in southern GBR waters. The concurrence of findings from an independent method of abundance estimation provides confidence in the CJS model used in this study to estimate abundance. Post-yearling survivorship was estimated from a 4 yr (1993 to 1996) photo-identification study of 517 individual humpbacks sighted at 2 seasonally sequential overwintering sites (Hervey Bay, Whitsundays) using a robust design CJS modelling approach with estimators that account for bias due to temporary emigration. A reduced form CJS model (constant survival, time-varying resight likelihood) also fitted the data well with the mean annual survival rate for the EAGVS humpbacks estimated at 0.966 (95% CI: 0.87 to 1.00). The good fit of the robust design survival rate model provides further confidence in the Hervey Bay abundance model, which suggests that the EAGVS has been recovering but at a slow and variable rate.
Results of studies of the structure and dynamics of two humpback whale stocks of the southern hemisphere (group IV, 70º E.-130°E.; group V, 130º E.-170º W.) are drawn together. Estimates are made of recruitment and mortality rates, and an assessment is made of the yields to be taken from these stocks under various conditions.
The two stocks are shown to be, in the main, independent of one another although there is a negligible sporadic exchange between them. The group V stock is shown to fragment, but probably randomly, in its northern migration.
Reproduction, nutrition, and growth are described. Birth rate of females is estimated to be 0.186, and since the sex ratio is approximately 1, the total birth rate is about 0.37. Parameters (von Bertalanffy) for growth are L∞ 42.58 ft for males, 45.21 ft for females; k(male) = 0.266, k(female): = 0.205.
The history of exploitation is reported.
Population structure is described from evidence drawn from examination of commercial catches; substantial changes in recent years (reduction of the numbers in older groups) are described.
Measurement of effort, and an analysis of variations in selectivity of the killings are reported in detail.
Decline in the abundance of these groups, group IV steadily since 1954 and group V sharply since 1959, is described.
Total mortality, natural mortality, fishing mortality, and recruitment rates are estimated and are used in estimating stock numbers and sustainable yields. The group IV stock probably consisted of 12,000-17,000 individuals in its unfished state, of about 10,000 individuals in 1949, and no more than 800 in 1962. The group V stock probably contained about 10,000 individuals in its unfished state, but only 500 or less in 1962. In its present state, group IV could give a sustainable yield of 18 (range 4-32) whales, and group V of 12 (range 3-21) whales. The maximum yields these stocks could sustain in completely regenerated state are: group IV, 390 whales per year; group V, 330 whales per year. Group IV would require 28-49 years to reach that state, group V would require 36-63 years.
Behavioral scientists have developed methods for sampling behavior in order to reduce observational biases and to facilitate comparisons between studies. A review of 74 cetacean behavioral field studies published from 1989 to 1995 in Marine Mammal Science and The Canadian Journal of Zoology suggests that cetacean researchers have not made optimal use of available methodology. The survey revealed that a large proportion of studies did not use reliable sampling methods. Ad libitum sampling was used most often (59%). When anecdotal studies were excluded, 45% of 53 behavioral studies used ad libitum as the predominant method. Other sampling methods were continuous, one-zero, incident, point, sequence, or scan sampling. Recommendations for sampling methods are made, depending on identifiability of animals, group sizes, dive durations, and change in group membership.
The recognized calving grounds of humpback whales (Megaptera novaeangliae) that breed along the Western Australian coast (Breeding Stock D) extend along the Kimberley coast between Camden Sound and Broome (15°–18°S). However, there are reports of neonates further south, suggesting that the calving areas may be poorly defined. During aerial photogrammetric research in 2013 and 2015, we sighted large numbers of humpback whale calves along North West Cape (21°47′–22°43′S). We estimated the minimum relative calf abundance to be 463–603 in 2013 and 557–725 in 2015. We categorized the calves as either neonate or post neonate according to their color and size. The majority of calves sighted in both years (85% in 2013; 94% in 2015) were neonates. Our observations indicate that a minimum of approximately 20% (17.1%–24.3%) of the expected number of calves of this population are born near, or south of, North West Cape. We thus demonstrate that the calving grounds for the Breeding Stock D population extend south from Camden Sound in the Kimberley (15°S) to at least North West Cape (22°43′S), 1,000 km southwest of the currently recognized calving area.
The E Australian Megaptera novaeangliae stock severely depleted by 1962, is now recovering at 9.7% per annum. The stock disperses in the sheltered waters of the Great Barrier Reef to breed although some calving occurs at higher latitudes. -from Author
Satellite tags were deployed on 47 humpback whales (Megaptera novaeangliae) in Panama and Ecuador between 2009 and 2015 to monitor both short- and long-distance movements within the breeding season. Ultimately, data from 37 animals (23 mothers with a calf and 14 unsexed adults) were included in the assessment. Transmissions were filtered and behavior states defined using a Bayesian state-space model. Mean tag longevity was 14.2 d (SD = 12.43; range: 1 to 70 d), and longevity was significantly longer in mothers (53%) than in unsexed individuals (t test = 2.43, p = 0.02). Based on the extent of their movements, two different habitat use patterns were recognized and referred to as short range (SR) and long range (LR). SR movements were associated mainly with slow, area-restricted movements (ARM) and short periods of fast, directed movement (FDM). LR movements were related mainly to FDM and, in some cases, with short ARM periods. We found significant differences in the proportion of time spent in each behavioral mode and in swim speed between mothers and unsexed individuals (p < 0.01, in all cases). Mothers displaying SR movements stayed in relatively small areas with back and forth movements up to 350 km along the coast; the 95% home range (kernel density) was estimated to be 61,105 km² in whales from Panama and 26,331 km² in whales from Ecuador. In mothers displaying LR movements, distribution range was seven times greater in Panama and up to 2.5 times greater in Ecuador. Since tag longevity was not significantly different between SR and LR movements in females (t test = 0.063, p > 0.05), a shift from the nursing to migration phase is a plausible explanation for this increased range. Information from unsexed animals is inconclusive because of the short tracking periods. Mothers were distributed closer to shore than other tagged unsexed individuals, but both types of whales swam into deeper waters mainly during migration. Our results confirm maternal-biased stratification in this population along the entire breeding range. These findings have important implications for coastal management, including reduction of risk posed by human activities such as bycatch, ship strikes, and whale watching.
The east coast of Australia experiences one of the world's largest annual humpback whale (Megaptera novaeangliae) migration, with an estimated 14 000 individuals in 2010. However, increasing coastal development is accelerating the environmental pressure on migrating marine megafauna. Consequently, solutions to better manage humpback whale presence in urbanised waters are required. We have developed a novel survey method that can be applied to operating whale watch vessels, better integrating the tourism industry into research and ultimately coastal management in urbanised coastal waters. Preliminary results from the first season of observation (May-November 2010) in the Gold Coast bay showed a successful survey return of over 500 individuals that included 14 286 behavioural state observations. The data were analysed in terms of most commonly observed behaviours, movement, pod size and composition. The numbers of mothers with calves were highest in September and October and both resting and feeding behaviours were documented, indicating the importance of the bay for these individuals. Our pilot study demonstrated that the benefits of whale watch, boat-based data collection can outweigh its limitations when strategically deployed and carefully analysed. This edition first published 2013
Among the large baleen whales, humpbacks are notable for the variety of different white and black patterns and slight morphological differences which can be observed between individuals (Lillie, 1915; Matthews, 1937; Pike, 1953; Schevill and Backus, 1960). Observations in the field and inspection of photographs suggest that variations in the shape of the dorsal fin or in the disposition of body scars can sometimes be used to identify individual humpback whales. It is primarily the pattern on the underside of the flukes which appears to us to provide the most positive discrimination between individual humpback whales. This pattern varies from nearly all white to nearly all black, but characteristically contains a variety of black or white patches, lines or streaks.
The crude birth rate during 1979-87 ranged from 0.045-0.103 (mean 0.079), with no significant year-to-year variation. An alternative measure gave a mean reproductive rate of 0.41 calves per mature female per year. Data suggest that the majority of females attain sexual maturity by the age of 6. Of 94 calves born prior to 1987, 72 (76.6%) were resighted in at least one year after separation from their mothers, providing further support for the belief that the composition of a humpback whale feeding stock is determined matrilineally. Entanglements in commercial fishing gear may represent a significant source of mortality in this population. -from Authors
Humpback whales congregate annually in low-latitude winter breeding and calving grounds. While on these grounds, females with a dependent calf ('maternal females') are sometimes closely at-tended by one or more male escorts. Using data collected from a shore-based observation platform in the Hawaiian Islands, we tested the hypothesis that the spatial distribution of maternal females is driven primarily by avoidance of males. As predicted, we found that (1) pods containing a calf oc-curred in significantly shallower water than pods that did not contain a calf, (2) unescorted maternal females occurred in significantly shallower water than escorted maternal females, (3) the number of males escorting a female decreased significantly with decreasing water depth, and (4) the swim-ming speed of maternal females increased as a function of male presence, with escorted females travelling significantly more rapidly than unescorted females and a significant positive correlation between swimming speed and number of escorts. We suggest that maternal females incur increased energetic costs when escorted by males and consequently position themselves in shallow waters to reduce the likelihood of unwanted male attention.
Understanding the patterns of spatial and temporal distribution in threshold habitats of highly migratory and endangered species is important for understanding their habitat requirements and recovery trends. Herein, we present new data about the distribution of humpback whales (Megaptera novaeangliae) in neritic waters off the northern coast of Peru: an area that constitutes a transitional path from cold, upwelling waters to warm equatorial waters where the breeding habitat is located. Data was collected during four consecutive austral winter/spring seasons from 2010 to 2013, using whale-watching boats as platforms for research. A total of 1048 whales distributed between 487 groups were sighted. The spatial distribution of humpbacks resembled the characteristic segregation of whale groups according to their size/age class and social context in breeding habitats; mother and calf pairs were present in very shallow waters close to the coast, while dyads, trios or more whales were widely distributed from shallow to moderate depths over the continental shelf break. Sea surface temperatures (range: 18.2–25.9°C) in coastal waters were slightly colder than those closer to the oceanic realm, likely due to the influence of cold upwelled waters from the Humboldt Current system. Our results provide new evidence of the southward extension of the breeding region of humpback whales in the Southeast Pacific. Integrating this information with the knowledge from the rest of the breeding region and foraging grounds would enhance our current understanding of population dynamics and recovery trends of this species.
This study is the first on-water survey and photo-identification effort of humpback whales in the Great Barrier Reef Marine Park Cairns/Cooktown Management Area. A total of 138.9 survey hours were logged on the ocean near Port Douglas/Cairns area covering 2540.96 km during 21 days in the field, 21 July – 16 August 2009. A total of 28 humpback whale groups were observed, comprised of 55 animals (33 adults, 12 sub-adults, 10 calves) with an average of 2.6 (total) animals and 1.3 pods observed per day. Twenty-four whales were individually identified, with an additional seven fluke ID images contributed by a Cairns whalewatch operator. Seven whales were resighted (22.6%) to Pacific Whale Foundations' 'Breeding Stock E/Area V Humpback Whale Catalogue'. Thirty percent of the groups observed during surveys contained newborn calves indicating this region may be an important nursery area for Breeding Stock E1 humpback whales. The early season, high percentage presence of mothers with newborn calves, and sub-adult whales suggests that migration patterns of east Australian humpbacks may not be as straightforward as previously reported.
A bstract
Despite the extensive use of photographic identification methods to investigate humpback whales in the North Pacific, few quantitative analyses have been conducted. We report on a comprehensive analysis of interchange in the North Pacific among three wintering regions (Mexico, Hawaii, and Japan) each with two to three subareas, and feeding areas that extended from southern California to the Aleutian Islands. Of the 6,413 identification photographs of humpback whales obtained by 16 independent research groups between 1990 and 1993 and examined for this study, 3,650 photographs were determined to be of suitable quality. A total of 1,241 matches was found by two independent matching teams, identifying 2,712 unique whales in the sample (seen one to five times). Site fidelity was greatest at feeding areas where there was a high rate of resightings in the same area in different years and a low rate of interchange among different areas. Migrations between winter regions and feeding areas did not follow a simple pattern, although highest match rates were found for whales that moved between Hawaii and southeastern Alaska, and between mainland and Baja Mexico and California. Interchange among subareas of the three primary wintering regions was extensive for Hawaii, variable (depending on subareas) for Mexico, and low for Japan and reflected the relative distances among subareas. Interchange among these primary wintering regions was rare. This study provides the first quantitative assessment of the migratory structure of humpback whales in the entire North Pacific basin.
A bstract
Here, we examine the distribution, habitat use, and migratory destinations of North Pacific humpback whales wintering off Central America. Coastal boat surveys were conducted off Costa Rica and Panama between 1996 and 2003. In 1999, a broader survey was conducted along most of Central America. Over 23,000 km were surveyed, with the greatest effort off southern Costa Rica. We made 191 sightings of 320 individual humpback whales. Whales were seen between 14°N and 8°N, making this the most southerly of the North Pacific wintering areas. Encounters included singles, adult pairs, singers, and mother/calf pairs. Mother/calf pairs accounted for 27% of all groups sighted, which is one of the highest sighting rates reported among North Pacific wintering areas. Sixty percent of sightings occurred in depths <50 m. Average sea surface temperature was 28.6°C (±1.0 SD). Ninety percent of the 77 unique whales photo‐identified were also seen in the California–Oregon–Washington feeding aggregation. The 1999 survey showed that humpback whales were widely distributed along the Central American coast at relatively low densities. The extensive distribution of animals, the higher proportion of calves, and the almost exclusive migration to a single feeding area contrast with observations in other regions.
Twelve female humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine produced first-observed calves at ages ranging from 5 to 7 years. These data confirm that most females of this species attain sexual maturity at an average age of approximately 5 years. Observations in the West Indies of two males, aged 6 and 7 years, engaged in breeding-related behavior that is characteristic of mature animals suggests that males attain sexual maturity within a similar range of ages to females, although they may not be able to successfully engage in intrasexual competition until later in life. These data imply that the examination of ear plugs to determine the age of dead humpback whales should be based upon an assumed annual growth rate of two growth layer groups, not one.
The portion of the Area V (130°E–170° W) humpback whale Megaptera novaeangliae stock that migrates along the east Australian coast is estimated to have numbered 1900 ± 250 in 1992 compared with a population possibly as low as 100 at the conclusion of whaling in 1962. The average annual rate of increase from 1984 to 1992 is estimated to have been 11·7% with a 95% confidence interval of 9·6–13·8%. This level of recovery suggests that, in the post whaling period, there have been no environmental factors detrimental to this particular stock.
Humpback whales Megaptera novaeangliae which migrate along the east Australian coast comprise part of the Area V (130°E–170°W) stock. Commercial exploitation of the species ceased in east Australian waters in 1962. From 1978 to 1982 observations were made from headland areas in the vicinity of latitude 27°S and the resultant data were compared with those obtained from the same latitude during the last two years of whaling operations. It appears that the east Australian humpback whale stock has recovered slightly in the past 20 years. Data collected from other locations along the east Australian coast suggest that previous whaling operations have not affected humpback whale migration patterns in that region. Sheltered waters within the Great Barrier Reef between latitudes 16°–21°S appear to be an important breeding ground for the east Australian humpback whale stock.