Occurrence Of Humpback Whales Research Articles

The most southerly occurrence of humpback whales in the western Weddell Sea

The most southerly occurrence of humpback whales in the western Weddell Sea

Historical occurrence and distribution of humpback whales in the eastern and southern Caribbean Sea, based on data from American whaling logbooks

The best-known present-day wintering areas for the North Atlantic population of humpback whales (Megaptera novaeangliae) are in the northern West Indies, notably off the island of Hispaniola. However, it is known that in the nineteenth century American whalers hunted humpbacks in the Windward Islands (primarily from Guadeloupe southwards), along the coast of Trinidad, in the Gulf of Paria and westwards along the Venezuelan coast. To investigate the historical distribution and occurrence of humpback whales, data were extracted from nineteenth century American whaling logbooks and journals covering 48 voyages by 29 vessels to the West Indies from 1823-1889. Humpback whale records in these documents came from a geographical area that encompassed Haiti to the coast of Venezuela. Of 807 records in which whales were mentioned (as sightings, strikes or catches), the largest number was from the Windward Islands and Venezuela, especially St Vincent and the Grenadines (319 records covering an estimated 958 humpbacks), Guadeloupe (190 records, 592 humpbacks), Dominica/Martinique/St Lucia (74 records, 193 humpbacks) and Venezuela (64 records, 216 humpbacks). These totals should be regarded only as approximate indicators of the relative abundance of whales since the effort involved cannot be meaningfully quantified. Similarly, effort-uncorrected data suggest that the peak months for humpback whales in the Windward Islands were February, March and April. Few sightings were recorded off the Dominican Republic after March, but this may reflect a lack of effort there in April and May. However, humpbacks apparently were abundant in the Windwards in April and even May, which is not the case in the major present-day wintering areas off Hispaniola. With one notable exception, there is little evidence in the logbooks and journals that humpbacks were taken on a more than casual basis in waters off Hispaniola, where the major aggregations are found today; possible explanations for the marked contrast in present versus historical distribution are discussed. The highly seasonal visitation of the West Indies by the American nineteenth-century whalers precludes a meaningful investigation of the possibility that some humpbacks from the Southern Hemisphere migrated to the Caribbean Sea in the austral winter.

Humpback whale (Megaptera novaeangliae) occurrence in the Mediterranean Sea

Humpback whales were considered extremely rare in the Mediterranean Sea until recently. Only two confirmed records were known from a period of more than 100 years and both were from the western basin. However, nine new observations spread across both Mediterranean basins have been recorded since 1990. This increase in numbers and range during a relatively short period of time seems to be a new, growing trend, suggesting that the occurrence of humpback whales in the Mediterranean Sea is no longer accidental, but occasional. It coincides with the recovery of some stocks of the expanding North Atlantic population after their depletion during a long period of whaling. The true reason behind increased humpback whale entries in the Mediterranean Sea and their exact origin cannot be known until new occurrences are properly photo-identified and sampled genetically.

Occurrence and distribution of cetaceans off northern Angola, 2004/05

The occurrence and distribution of cetacean species off northern Angola was examined using dedicated survey data and incidental sighting records. Dedicated surveys for cetaceans were carried out during two geophysical seismic surveys off northern Angola between August 2004 and September 2005. A total of 3,268hr of survey effort data were collected, resulting in 779 on-effort cetacean sightings. There were 263 sightings reported off-effort and incidentally from other platforms and sports fishermen. With 21 cetacean species confirmed, the cetacean community off northern Angola is diverse and primarily tropical in characteristic, comprising four species of baleen whale, two sperm whale species, at least two beaked whale species, and 13 species of delphinid. Humpback and sperm whales were the most frequently recorded cetaceans. The occurrence of humpback whales was significantly higher within neritic waters, and during the winter and spring months in association with seasonal occupancy of their West African breeding grounds. Sperm whales were recorded in water depths exceeding 1,000m and demonstrated significant seasonality, with peak occurrence during the summer and autumn. Atlantic spotted dolphins and common dolphins (Delphinus sp.) were the most numerous delphinids recorded, with spotted dolphins showing a significant seasonal peak during the spring and summer, and common dolphins in the winter. Other species recorded included fin whale, sei whale, Bryde’s whale, dwarf sperm whale, Cuvier’s and Mesoplodon beaked whales, killer whale, short-finned pilot whale, false killer whale, melon-headed whale, Atlantic humpback dolphin, rough-toothed dolphin, Risso’s dolphin, bottlenose dolphin, Pantropical spotted dolphin, spinner dolphin, Clymene dolphin and striped dolphin. Further research is required to document the cetacean community in Angola, particularly given the unknown threat from fishery bycatch and the increasing level of oil and gas exploration in the region.

Status and distribution of humpback whales (Megaptera novaeangliae) in northern Luzon, Philippines

Since the verification of the occurrence of humpback whales in the Babuyan Islands, Philippines in 1999, studies have been carried out on their status and distribution. Boat-based surveys of the waters around the islands were conducted from 2000-03. In 2003, a survey was also conducted off the eastern coast of Northern Sierra Madre. Once the whales were sighted, the location, group composition and behaviour were noted, fluke photo-identifications taken, sloughed skin and biopsy samples collected and songs recorded. A total of 367 humpback whale sightings were documented in four seasons around the Babuyan Islands. However, a cow-calf pair sighting off the coast of Northern Sierra Madre indicates that this breeding area may extend farther south. A total of 69 individuals have been photo-identified from 1999- 2003. Re-sightings across years are as follows: one individual was sighted for three consecutive years (2001-03); two individuals for two consecutive years (2001-02 and 2002-03); while three individuals were sighted in two different years (1999 and 2002; 2001 and 2003). Twelve of the 40 individuals photo-identified in the Philippines from 1999-2002 were matched to humpback whales identified in Ogasawara and Okinawa, Japan, including one whale that moved between these regions in one season. These matches indicate that the Philippine humpback whales are part of this greater western Pacific population. A subjective comparison between humpback whale songs recorded in the Philippines and Hawaii in 2002 indicated marked similarities. A total of nine distinctive themes were identified; seven of these were common to songs from both regions. The similarity in songs suggests humpback whales in the Philippines mix to some degree, at least acoustically, with the whales in Hawaii and the rest of the Pacific basin.

The occurrence of humpback whales across the Hawaiian archipelago revealed by fixed and mobile acoustic monitoring

The occurrence of humpback whales (Megaptera novaeangliae) across the 2600 km of Hawaiian archipelago, which include the remote atolls, banks, and seamounts of Papahānaumokuākea Marine National Monument (PMNM), remains poorly understood. Previous surveys for humpback whales beyond the main Hawaiian Islands have been scarce due to limited access and the challenging winter conditions typically found in PMNM when whales are present. To overcome these limitations, a combination of moored acoustic recorders and a Wave Glider autonomous surface vehicle were used to acoustically monitor eight locations and survey approximately 1500 km of the Hawaiian archipelago for the occurrence of humpback whale song during the 2019-2020 breeding season. Relative song prevalence was established using a machine learning tool and by quantifying the level of song chorusing. A generalized additive model framework was applied to understand the associations between habitat variables and humpback whale song occurrence, and sound propagation modeling was performed to examine whether acoustic propagation influenced observed patterns. Whale song was recorded at all monitored and surveyed locations across the archipelago, albeit in varying amounts. Among the locations monitored with moored recorders, the highest and most sustained seasonal chorusing levels were measured off Maui followed by French Frigate Shoals (Kānemilohai), Hawaii Island, Middle Bank, Oahu, Kauai, Gardner Pinnacles (Pūhāhonu) and Pearl and Hermes Reef (Holoikauaua), respectively. The Wave Glider mission to PMNM revealed that song prevalence was highest at Middle Bank and gradually decreased further to the northwest, reaching a minimum at Gardner Pinnacles (Pūhāhonu). However, song occurrence increased again at Raita Bank, remaining high between Raita Bank and the Northampton Seamounts. The results reveal that nearly the entire Hawaiian archipelago is exploited by humpback whales during the winter and early spring months. Moreover, song occurrence patterns suggest that there may be more structure in the distribution of whales in PMNM than previously known and raises questions about whether multiple subpopulations occur across the archipelago.

The Beat Goes On: Humpback Whale Song Seasonality in Antarctic and South African Waters

Little is known of the movements and seasonal occurrence of humpback whales (Megaptera novaeangliae) of South Africa and the Antarctic, populations once brought to near extinction by historic commercial whaling. We investigated the seasonal occurrence and diel-vocalizing pattern of humpback whale songs off the west coast of South Africa (migration route and opportunistic feeding ground) and the Maud Rise, Antarctica (feeding ground), using passive acoustic monitoring data collected between early 2014 and early 2017. Data were collected using acoustic autonomous recorders deployed 200-300 m below the sea surface in waters 855, 1,118 and 4,400 m deep. Acoustic data were manually analyzed for humpback whale vocalizations. While non-song calls were never identified, humpback whale songs were detected from June through December in South African waters, with a peak in percentage of acoustic occurrence around September/October in the austral spring. In Antarctic waters, songs were detected from March through May and in July (with a peak occurrence in April) where acoustic occurrence of humpback whales was negatively correlated to distance to the sea ice extent. Humpback whales were more vocally active at night than in the day at all recording sites. Detection range modelling indicates that humpback whale vocalizations could be detected as far as 18 and 45 km from recorders in South African and Antarctic waters, respectively. This study provides a multi-year description of the offshore acoustic occurrence of humpback whales off the west coast of South Africa and Maud Rise, Antarctica, regions that should continue to be monitored to understand these recovering populations.

Cetacean acoustic monitoring across the Hawaiian archipelago: Building on Whitlow Au’s legacy

The Hawaiian islands are home to more than 20 species of cetaceans and are the principal breeding ground of the north Pacific humpback whale population. The archipelago stretches more than 2500 km from Hawaii Island to Kure Atoll, creating a significant challenge for monitoring the occurrence and distribution of cetaceans across such a vast range. To meet this challenge, the National Oceanic and Atmospheric Administration and the U.S. Navy have been engaged in a three-year effort to monitor the marine soundscape of the Hawaiian archipelago known as the SanctSound Project. Bottom-moored acoustic recorders were deployed at multiple locations across the Hawaiian Islands Humpback Whale National Marine Sanctuary and the Papahānaumokuākea Marine National Monument to examine the occurrence of humpback whales and odontocetes based on the relative prevalence of their acoustic signaling. Anthropogenic sound sources were also studied to understand how these co-occur with cetaceans. Substantial spatial and temporal variability was observed in the prevalence of whale song and dolphin acoustic activity across locations with high cetacean presence sometimes overlapped with elevated anthropogenic activity. This work helps expand our understanding of how cetaceans use the archipelago and builds on the legacy of Whitlow Au, who pioneered cetacean acoustic monitoring in Hawaii.

Seasonal distribution, abundance, habitat use and population identity of humpback whales in Oman

Previously published data on the occurrence of humpback whales (Megaptera novaeangliae) in the Arabian Sea suggests that the region hosts anon-migratory population that adheres to a Northern Hemisphere breeding cycle. In order to investigate the distribution and abundance of thispopulation, twelve small boat surveys were conducted in three main locations off the coast of Oman between February 2000 and November 2004.Humpback whales were observed during surveys in Dhofar and Gulf of Masirah on Oman’s Arabian Sea coast, but not during surveys in the Muscatregion in the Gulf of Oman. An even ratio of males to females was observed and sampled during surveys in the Gulf of Masirah, which was surveyedin October and November (n = 38), while almost all whales sampled in Dhofar in February/March were male (n = 28). Song was detected frequentlyin the bay surrounding the Halaniyat Islands (formerly known as the Kuria Muria Bay) in February/March, but observations of mother-calf pairswere sparse, and competitive groups were absent. Feeding was observed in both October/November and February/March, but behavioural andenvironmental observations indicate that the Gulf of Masirah is primarily an important feeding ground, while the Dhofar region, particularly theHalaniyat Bay, may be a breeding area. However, limited survey effort and a lack of recent observations of mother-calf pairs or competitive groupsraises the possibility that the primary mating, calving and nursing areas are yet to be identified. Sixty-four individual whales were identified usingphotographs of dorsal fins or tail flukes. A high rate of re-sightings between years and between survey areas at different times of the year indicatesyear-round residence off the coast of Oman. A Chapman’s modified Petersen estimator was applied to various data pairings to calculate abundance.All pairings yielded estimates of less than 100 individuals, but sample sizes were small and there were various sources of possible bias. Analysisof scarring on the caudal peduncle region of identified individuals in Oman indicates that between 30 and 40% are likely to have been involved inentanglements with fishing gear. Comparison of the Oman photo-identification catalogue with those from Zanzibar, Antongil Bay (Madagascar)and Mayotte and the Geyser Atoll (Comoros Archipelago), yielded no photographic matches. These data are consistent with the hypothesis of adiscrete population. The distribution of fluke pigmentation rankings from the Oman catalogue, which varied significantly from those of Madagascarand Mayotte, provides further evidence for this theory. The evidence presented here provides a strong underpinning for the recent IUCN Red Listclassification of the Arabian Sea sub-population of humpback whales as Endangered. In light of ongoing coastal development and other threats tothis population’s habitat and future survival, urgent research and conservation measures are recommended.

Sudden seasonal occurrence of humpback whales Megaptera novaeangliae in the Firth of Forth, Scotland and first confirmed movement between high-latitude feeding grounds and United Kingdom waters

Here we report on the sudden seasonal occurrence of humpback whales Megaptera novaeangliae within the Firth of Forth, Scotland, UK over the winter months of 2017 and 2018. Sightings and photographs collected by citizen scientists of the Forth Marine Mammal Project were inspected and a fluke photograph compared to existing catalogues from all known feeding and breeding grounds across the North Atlantic. No matches to breeding grounds were found but a fluke match to a non-catalogued individual in Svalbard (Norway) constitutes the first confirmed movement of a UK-recorded humpback whale from high-latitude feeding grounds. A different individual was photographed in the Firth of Forth in both 2017 and 2018, providing evidence of a whale returning to the Firth of Forth in consecutive years. Despite year-round observation, the discrete seasonality of sightings suggests that the Firth of Forth may represent a migratory stopover or alternative destination for humpback whales on their southbound migration. Overall, these findings constitute a formalised baseline of information regarding the occurrence of humpback whales in the Firth of Forth and contribute to our understanding of the migration habits of humpback whales in the eastern North Atlantic.

Singing through winter nights: Seasonal and diel occurrence of humpback whale (Megaptera novaeangliae) calls in and around the Gully MPA, offshore eastern Canada

AbstractHumpback whale use of areas off eastern Canada is poorly understood, a knowledge gap that could impact future conservation efforts. We describe the acoustic occurrence of humpback whales in and around the Gully Marine Protected Area (MPA), an eastern Scotian Shelf submarine canyon. Near‐continuous acoustic recordings sampling at 16 kHz were collected from the MPA and nearby slope areas from October 2012 to September 2014 using near‐bottom recorders. In an offshore region where humpbacks were thought to be rare, we observed calls from October to June with a peak in song and nonsong calls in December and January. This suggests that some individuals occur in Canadian waters in winter and the Gully region may be a North Atlantic humpback whale migratory corridor. Calls were predominantly songs indicating potential mating activities. Song and nonsong calls occurred more at sunset and during hours of darkness than during daylight. This study improves our understanding of the seasonal occurrence of humpback whales on the Scotian Slope and, more specifically, their use of an offshore protected area.

Humpback whales feed on hatchery-released juvenile salmon.

Humpback whales are remarkable for the behavioural plasticity of their feeding tactics and the diversity of their diets. Within the last decade at hatchery release sites in Southeast Alaska, humpback whales have begun exploiting juvenile salmon, a previously undocumented prey. The anthropogenic source of these salmon and their important contribution to local fisheries makes the emergence of humpback whale predation a concern for the Southeast Alaska economy. Here, we describe the frequency of observing humpback whales, examine the role of temporal and spatial variables affecting the probability of sighting humpback whales and describe prey capture behaviours at five hatchery release sites. We coordinated twice-daily 15 min observations during the spring release seasons 2010–2015. Using logistic regression, we determined that the probability of occurrence of humpback whales increased after releases began and decreased after releases concluded. The probability of whale occurrence varied among release sites but did not increase significantly over the 6 year study period. Whales were reported to be feeding on juvenile chum, Chinook and coho salmon, with photographic and video records of whales feeding on coho salmon. The ability to adapt to new prey sources may be key to sustaining their population in a changing ocean.

Humpback whale songs during winter in subarctic waters

The songs of the male humpback whales (Megaptera novaeangliae) have traditionally been associated with mating at tropical and subtropical mating grounds during winter. However, songs also occur out of mating season, both on feeding grounds in spring, late summer and fall. This study provides the first report of humpback whale singing behaviour in the subarctic waters of Northeast Iceland (Skjalfandi Bay) using long-term bottom-moored acoustic recorders during September 2008–February 2009 and from April to September 2009. Singing started in late November and peaked in February, within the breeding season. No songs were detected from spring to fall, despite visual detections of humpback whales. Non-song sound signals from humpback whales were detected during all recording months. Songs were partly composed of fundamental units common with other known mating grounds, and partly of song units likely unique to the study area. The variety of song unit types in the songs increased at the end of the winter recordings, indicating a gradual change in the songs throughout the winter season; as has been shown on traditional mating grounds. The relative proportion of songs compared with non-song signals was higher during dark hours than daylight hours. The short light periods of the winter, and where food is available, likely influence the daily occurrence of humpback whales’ songs in the subarctic.

Extended seasonal occurrence of humpback whales in Massachusetts Bay

Humpback whales (Megaptera novaeangliae) are known to utilize Massachusetts Bay as a feeding ground in the spring and summer, during the annual migration of the Gulf of Maine sub-population. However, there is a limited understanding of the pattern of humpback whale occurrence in this region outside of the feeding period. Passive acoustic monitoring of Massachusetts Bay over a two-year period, revealed an extended presence of acoustically active humpback whales throughout a majority of the study period (87%; 633 days of presence out of 725 days of acoustic monitoring). Humpback whale presence oscillated between lengthy periods of consistent presence (April to December) and relatively shorter periods of variable presence (December to March). Seasonal variation in presence was evident during three distinct phases: (1) maximum-presence from spring to early winter; (2) variable-presence in early winter and early spring; and (3) minimum-presence mid-winter. The variation in seasonal presence was concurrent with coarse migratory patterns of humpback whales, and yearly variations in presence presumably reflect a shift in the influx and efflux of whales between years. The extended presence of humpbacks in this area suggests that Massachusetts Bay is an important, year-round habitat for the Gulf of Maine sub-population, and may warrant revision of management and regulatory practices to reflect this presence.

Humpback whale Megaptera novaeangliae song reveals wintering activity in the Northwestern Hawaiian Islands

The main Hawaiian Islands (MHI) are the principal breeding ground for humpback whales in the North Pacific. Over the past 3 decades, population recovery from whaling-era losses has resulted in a steady increase in the number of whales wintering in Hawaiian waters and a geo- graphic expansion of their distribution in the MHI. Until recently, no existing evidence showed that this expansion included the islands, atolls, and banks of the Northwestern Hawaiian Islands (NWHI). To better understand the occurrence of humpback whales in the NWHI, 9 ecological acoustic recorders (EARs) were deployed at sites throughout the archipelago to record the occurrence of humpback whale song, an indicator of winter breeding activity. Song was found to be prevalent at Maro Reef, Lisianski Island, and French Frigate Shoals but was also recorded at Kure Atoll, Midway Atoll, and Pearl and Hermes Atoll. Both the timing and abundance of song at several locations closely followed trends observed on Oahu, which is one of the MHI, strongly suggesting that humpback whales use the NWHI as a wintering area. This finding is of particular relevance in light of recent suggestions that, based on photo-identification data, a yet undocumented wintering area exists somewhere in the central North Pacific. We propose that the NWHI could be that area.

Preliminary account of cetacean diversity and humpback whale (Megaptera novaeangliae) group characteristics around the Union of the Comoros (Mozambique Channel)

Abstract Cetacean diversity and occurrence has never been investigated in the Union of the Comoros, located in the northern Mozambique Channel. Small boat-based surveys were conducted during the austral winter of 2002, primarily to assess the occurrence of humpback whales (Megaptera novaeangliae) and whether the area represents a wintering ground where the species reproduce. All other cetacean species were also recorded. Opportunistic sighting records were used to provide information on the diversity of cetaceans occurring in the area. Between 2000 and 2003, 12 cetacean species were recorded around the Comoros, including: Megaptera novaeangliae, Stenella longirostris, Peponocephala electra, Stenella attenuata, Tursiops truncatus, Globicephala macrorhynchus, Mesoplodon densirostris, Physeter macrocephalus, Lagenodelphis hosei, Grampus griseus, Mesoplodon pacificus and possibly Tursiops aduncus. During the dedicated surveys, the humpback whale was the most commonly encountered species (72% of sightings) followed by the spinner dolphin (15%). Humpback whale group composition was heterogeneous, but mother-calf pairs were the most commonly sighted (49%). This study demonstrates that the Union of the Comoros is an important site for migrating humpback whales in the southwest Indian Ocean and for a wide variety of toothed cetacean species.

Numbers and seasonal occurrence of Humpback Whales, Megaptera novaeangliae, off Brier Island, Nova Scotia

Numbers and seasonal occurrence of Humpback Whales, Megaptera novaeangliae, off Brier Island, Nova Scotia