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This study addresses existing gaps in our understanding of the ecology of killer whales by investigating their habitat use dynamics in the Atlantic coastal waters of North Africa, the Iberian Peninsula, and the Gulf of Biscay. Despite previous research on their distribution during the Atlantic Bluefin tuna migration in the Strait of Gibraltar and adjacent waters, substantial knowledge gaps persist, particularly regarding their movement patterns beyond these regions and seasonal variations in habitat use. Utilizing killer whale occurrence records from 2020 to 2023 and considering environmental factors influencing prey presence, we employed seasonal spatial distribution models. MaxEnt models exhibited robust predictive performance, emphasizing distance to shore, depth, and sea surface temperature as key factors influencing killer whale habitat suitability. Spatial distribution patterns reveal a peak in coastal waters of the southern Iberian Peninsula and North Africa during winter and spring, with a significant shift northward and expansion during summer and autumn towards the Gulf of Biscay. This expansion suggests a broader distribution of killer whales in the Northeast Atlantic during warmer months, encompassing a diverse range of habitats. The research underscores a substantial interaction (47%) between killer whales and recreational vessels, posing concerns for both the killer whales and maritime safety. This study provides valuable insights on killer whale habitat use in the Atlantic waters from North Africa to the Gulf of Biscay, thereby supporting conservation and management efforts in the region. • Killer whales show dynamic habitat changes along the Atlantic coast. • Distance to shore, depth, and temperature shape habitat suitability. • Killer whale habitat suitability linked to tuna migration dynamics. • 47% of killer whale records involve interactions with recreational vessels. [ABSTRACT FROM AUTHOR]

Recovery of the endangered Southern Resident killer whales of the Salish Sea is impeded by threats such as vessel disturbances and noise. Reduction of vessel disturbances is key for recovering the population, but recreational vessel operators have high rates of noncompliance with regulations intended to reduce noise. Through a survey of 115 recreational boaters in Washington state, this study was an exploratory analysis of the normative and instrumental factors that may influence compliance. Recreational boaters self-reported having high levels of compliance with vessel regulations. They shared characteristics including a strong sense of responsibility to follow the rules, support for vessel regulations, concern about orca conservation, and a belief that other boaters do not comply with vessel regulations. These characteristics may predispose them to be more motivated by normative factors, such as a sense of personal responsibility, social norms, and participation in rulemaking, rather than instrumental factors based in enforcement and deterrence. This reflects how normative motivations may be more important for groups with certain characteristics, illuminating differences in motivations within a population of resource users. Due to this, management interventions should address both normative and instrumental motivations for compliance. Interventions that appeal to normative motivations based on social norms and personal responsibility, or education and outreach that fill knowledge gaps about regulations, may most influence the behavior of the boaters surveyed in this study. Nevertheless, enforcement and deterrence may still be useful for shaping compliance by boaters who are less represented in this study, such as tourists or fishers. • Boaters reported high levels of compliance, motivated by normative factors. • Certain characteristics predispose boaters to be motivated by normative factors. • Boaters had a strong sense of responsibility and concern for orcas. • Education and outreach are important to fill gaps in awareness about regulations. • Interventions based on normative factors should be complemented by enforcement. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the seasonal selection behavior of sea ice landscape of bowhead whales or Balaena mysticetus based on satellite tracking data of the whales across Eastern Canada-West Greenland. The study investigates the movement of the whales and their habitat selection throughout summer and winter seasons, and employs resource selection functions to evaluate their habitat selection behavior. The results show that bowhead whales preferred areas with low ice coverage, thin ice and small floe size during winter, while areas with high ice coverage, thick ice and large floe size during summer.

The article presents a study which looks into the implication of a certain novel approach in determining the factor which gives rise to the declining animal population in the U.S. A group of Steller's sea lions or Eumetopias jubatus from the western part of Alaska are accordingly used by the researchers upon the implementation of the study. In conjunction with this, three vital rates including fecundity, pup survival and non-pup survival, as well as four scaling functions are considered in the process as well.

Abstract: Blubber and liver samples were obtained for analysis of wide ranges of contaminants from killer whales (Orcinus orca) which were locked away in drifting sea ice on the coast of Rausu, the Shiretoko Peninsula in Eastern Hokkaido, Japan in February 2005. Among the organohalogen compounds analyzed, DDTs were the predominant contaminants with concentrations ranging from 28 to 220μg/g on a lipid-weight basis followed by PCBs and other organochlorine pesticides. PBDEs levels were two or three orders of magnitude lower than those of PCBs and DDTs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) derived by WHO mammal-TEF in killer whales were in the range of 110–440 pgTEQ/g. Mono-ortho coplanar PCBs contributed to 75–98% of total TEQs, indicating coplanar PCBs are significant contaminants for risk assessment in this species. The fact that hepatic residue levels of butyltins (from 13 to 770ng/g wet weight) were much higher than those of phenyltins may be reflecting extensive use of tributyltin as antifouling paint. [Copyright &y& Elsevier]

Exposure to persistent organic pollutants (POPs) is a key factor in predicting the collapse of global killer whale (Orcinus orca) populations due to reproductive and immune impacts. Blubber biopsies from killer whales (n = 25) were collected in the Russian Far East in 2002–2004. Biopsies were analyzed for ΣDDT, ΣPCB, and HCB concentrations. A subset of biopsies was further examined for additional contaminants, ΣPBDE, ΣHCH, ΣCHLD, mirex, and dieldrin. Mean concentrations were compared across resident (fish-eating) and transient (mammal-eating) ecotypes and between sexes. ΣPCB analytes (resident males 18,000, resident females 1200, and transient males 420,000 ng g−1 lw) and HCB (resident males 750, resident females 81, and transient males 6200 ng g−1 lw) differed significantly (p < 0.001). No significant difference was observed between sexes. Notable disparities in contaminant levels between ecotypes support the major toxicological theories of contaminant bioaccumulation and dietary impacts on individual contaminant load. • Blubber biopsies from killer whales in the Russian Far East were analyzed for organic contaminants. • PCBs and HCB were higher in transient (mammal-eating) than resident (fish-eating) killer whales. • Female resident killer whales had the lowest blubber contaminant levels. • Hexachlorinated PCBs and p,p'-DDE were the most prevalent homologs measured. • Biomagnification of POPs makes killer whales excellent sentinels of Arctic ecosystem health. [ABSTRACT FROM AUTHOR]