Surface images of bottlenose dolphins swimming with Antillean manatee calves in the shallow coastal waters (< 1.5 m deep) of Belize.

In all cases, the single dolphin and manatee calf were seen interacting. The manatee calf was also observed in echelon position. In Case 4, the manatee calf swam underneath the dolphin in echelon position. In Case 7, the calf also swam in echelon position with the dolphin.</p

Location of interspecies interactions between adult bottlenose dolphins and Antillean manatee calves (<i>n</i> = 10) from 1999 to 2020 in the coastal waters of Belize.

Location of interspecies interactions between adult bottlenose dolphins and Antillean manatee calves (n = 10) from 1999 to 2020 in the coastal waters of Belize.</p

Details on the 10 cases of interactions between adult bottlenose dolphins and Antillean manatee calves in Belize.

F = Female, M = Male, Unk = Unknown, R = Right, L = Left, N/A = Not available. Body lengths with “*” are estimations. Case 4 includes field observations of interactions between an adult bottlenose dolphin and an Antillean manatee calf and the observation of bite marks during health evaluations of the rehabilitation center in Belize, Wildtracks.</p

Compilation of surface video observations of three interactions between bottlenose dolphins and Antillean manatees documented in Belize.

Compilation of surface video observations of three interactions between bottlenose dolphins and Antillean manatees documented in Belize.</p

Illustration of wounds and scarring detected on four orphaned Antillean manatee calves rescued in Belize.

In Case 4, the calf presented with superficial wounds from tooth rakes, mostly clustered on its right pectoral fin and the right side of its body. The calf in Case 8 sustained major lacerations around her nares and on the left side of her face and presented with numerous tooth rakes on her left pectoral fin. The calf in Case 9 had tooth rakes on its right and left pectoral fins and its body. Tooth rakes were found on the top right and the left side of the calf’s body in Case 10.</p

Aerial imagery of bottlenose dolphins interacting with an Antillean manatee mother-calf pair during two flights filmed with small aerial drones.

In Case 3, an adult female dolphin and her calf detected a manatee mother-calf in shallow seagrass flats near St. Georges Caye. The dolphins oriented towards the manatees twice before swimming near them briefly and then departing. In Case 5, a single adult dolphin repeatedly encircled a manatee mother-calf pair for at least 4 min near Belize City. Images were exported as screenshots from high-resolution aerial video recordings gathered with a DJI Phantom 4 Pro (Case 3) drone on 30 June 2016 and a DJI Mavic Pro (Case 5) drone on 12 April 2020. Timestamps at the bottom right indicate the time of the exported frame from start of the interaction as captured by the camera of the aerial drone.</p

Aerial drone observations of two different interactions between bottlenose dolphins and Antillean manatee calves.

Aerial drone observations of two different interactions between bottlenose dolphins and Antillean manatee calves.</p

Information on dolphin tooth rakes found on the bodies of four orphaned Antillean manatee calves recovered for rehabilitation and rescue.

The mean distance between tooth rakes is consistent with inter-tooth distances reported for adult bottlenose dolphins: 5–14 mm [28]; 7–12 mm [18]; and 10.97–12.32 mm [21]. The distance between tooth rakes is presented as mean ± standard deviation, range, and the number of measurements taken between adjacent tooth rakes. R = Right; L = Left. Unk = Unknown.</p

Varying Diet Composition Causes Striking Differences in Legacy and Emerging Contaminant Concentrations in Killer Whales across the North Atlantic

Lipophilic persistent organic pollutants (POPs) tend to biomagnify in food chains, resulting in higher concentrations in species such as killer whales (Orcinus orca) feeding on marine mammals compared to those consuming fish. Advancements in dietary studies include the use of quantitative fatty acid signature analysis (QFASA) and differentiation of feeding habits within and between populations of North Atlantic (NA) killer whales. This comprehensive study assessed the concentrations of legacy and emerging POPs in 162 killer whales from across the NA. We report significantly higher mean levels of polychlorinated biphenyls (PCBs), organochlorine pesticides, and flame retardants in Western NA killer whales compared to those of Eastern NA conspecifics. Mean ∑PCBs ranged from ∼100 mg/kg lipid weight (lw) in the Western NA (Canadian Arctic, Eastern Canada) to ∼50 mg/kg lw in the mid-NA (Greenland, Iceland) to ∼10 mg/kg lw in the Eastern NA (Norway, Faroe Islands). The observed variations in contaminant levels were strongly correlated with diet composition across locations (inferred from QFASA), emphasizing that diet and not environmental variation in contaminant concentrations among locations is crucial in assessing contaminant-associated health risks in killer whales. These findings highlight the urgency for implementing enhanced measures to safely dispose of POP-contaminated waste, prevent further environmental contamination, and mitigate the release of newer and potentially harmful contaminants

Values used in the NOAA climate change web portal to generate climate exposure maps for 108 marine mammal stocks in the western North Atlantic, Gulf of Mexico, and Caribbean Sea.

Values used in the NOAA climate change web portal to generate climate exposure maps for 108 marine mammal stocks in the western North Atlantic, Gulf of Mexico, and Caribbean Sea.</p