The New York Bight is undergoing rapid anthropogenic change amidst an apparent increase in baleen whale sightings. Though survey efforts have increased in recent years, the lack of published knowledge on baleen whale occurrence prior to these efforts impedes effective assessments of distributional or behavioural shifts due to increasing human activities. Here we synthesize opportunistic sightings of baleen whales from 1998–2017, which represent the majority of sightings data prior to recent survey efforts, and which are largely unpublished. Humpback and fin whales were the most commonly sighted species, followed by North Atlantic right whales and North Atlantic minke whales. Important behaviours such as feeding and nursing were observed, and most species (including North Atlantic right whales) were seen during all seasons. Baleen whales overlapped with multiple anthropogenic use areas, and all species, but of particular importance North Atlantic right whales, were sighted outside the spatial and temporal bounds of the Seasonal Management Areas for North Atlantic right whales. These opportunistic data are vital for providing a baseline and context of baleen whales in the New York Bight prior to broad-scale efforts and facilitate interpretation of current and future observations and trends, which can more accurately inform effective management and mitigation efforts.

Killer whales Orcinus orca are considered to be relatively uncommon in tropical waters. Few sightings have been reported from the west coast of Africa due to a paucity of survey coverage. We present data on 32 killer sightings from tropical waters off Angola (N = 18), Gabon (N = 7), São Tomé (N = 6) and Cameroon (N = 1), comprising a combination of dedicated survey sightings (N = 21) and reliable anecdotal records (n = 11). Killer whales were reported from coastal waters, the shelf edge and deep, oceanic areas. Sightings indicate a probable year-round occurrence of killer whales within the region. Mean group size was 5.6 animals. There was no difference in group size between sightings in waters >200 m deep and those on the continental shelf. No photo-identification matches were found between Angola, Gabon and São Tomé. Re-sightings of two individuals occurred annually in São Tomé during 2002–2004. Killer whales had external appearance consistent with the Type A nominate species form. Antagonistic encounters were recorded between killer whales and humpback whales Megaptera novaeangliae off Angola, Gabon and Cameroon, and with sperm whales Physeter macrocephalus off Angola. Predation on ocean sunfish Mola mola was recorded in São Tomé, and possible predation on sharks was recorded twice in Gabon.

Habitat preference is driven by a complex interaction among behavioural patterns, biological requirements, and environmental conditions. These variables are difficult to determine for any species but are further complicated for migratory marine mammals, such as humpback whales Megaptera novaeangliae. Patterns of habitat use in relation to social organization potentially exist for this species on their wintering grounds. Using an integrated GIS approach, we examined the degree to which spatial patterns of habitat stratification are correlated within different humpback whale group types from 6 years of sighting data (1996–2001) collected on the Antongil Bay, Madagascar, wintering ground. Stratification of humpback whale sightings by behavioural classification showed significant variation in depth and distance from shore. Distribution by depth could not be described as a function of group size but could be described as a function of social organization, with mother–calf pairs showing a strong preference for shallower water compared to all other group types. Group size and social organization seem to be factors in distribution by distance from shore. Significant diurnal patterns in distribution by depth and distance from shore also exist, where mother–calf groups maintain a relatively stable distribution and pairs and competitive groups are the most variable. Patterns of habitat preference on this wintering ground appear to be guided by social organization, where distribution by depth and distance from shore highlight areas critical to conservation.