Orcas are the largest member of the dolphin family, the male dorsal fin reaching 1.5m. Females can live 90 years in the wild, and many individuals stay within their matrilineal family their entire lives. Orca need to master a huge range of skills: hunting tactics, social interaction, knowledge of feeding and breeding grounds, and migration routes. Adult members of the pod teach the young these essential life skills, and one day they will pass on these skills to their own children. This knowledge forms a kind of orca ‘culture’, handed down from generation to generation.
They eat a variety of different prey, including fish, seals, dolphins, sharks, rays, whales, octopuses and squids and have even been seen killing otters and seabirds. But often a pod will specialise in eating just one type of animal.
Due to their distinctive patterning and large dorsal fins, Orca can be individually identified with several unique pods moving through Scottish waters. They are a very mobile species but deemed highly site-faithful, returning to the same areas in Scotland each year during spring and summer. For example, individuals have been photo-identified moving annually between Iceland to Shetland, Orkney, and the North East of Scotland.
Action Needed
- Support inclusion of Orca in management plans of relevant Scottish MPAs.
- Support the implementation of the Scottish Biodiversity Strategy; specifically:
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- Expand Scottish marine protected areas to 30% by 2030
- Increase the number of sites in Scotland’s Marine Protected Area network with specific fisheries management measures,
- Invest in nature – implementation of Biodiversity Investment plan
- Regularly re-evaluate the efficacy of current regulations and improve waste management to address chemical pollution.
- Publish the Cetacean Conservation strategy
- Restrict the production and use of all emerging PFAS chemicals as a group under UK REACH by 2025 with strategies to phase out PFAS. Establish an enforceable compliance mechanism for eliminating persistent organic pollutants (POPs).
- Implement mitigation measures such as limiting the dredging of PCB-contaminated rivers and estuaries, preventing PCB leakage from old landfills and regulating demolition of PCB-containing buildings and products.
- Include consideration of PCB tissue concentrations in the assessment of favourable conservation status of marine mammal species in European and UK policy.
Threats
High concentrations of contaminants may be contributing to the unsuccessful reproduction of the west coast population. Orca are vulnerable to bioaccumulation of toxic pollutants, with the level of chemicals such as polychlorinated biphenyls (PCBs) increasing up through the food chain. Reduced prey availability and increased noise pollution can lead to orca changing their behaviour and movements, impacting on feeding and breeding success.
Fishing pressure & gear entanglement can also have an impact on orca. As with all species of cetacean, the unknown impacts of climate change on them, their prey and the habitats on which they rely, is an overarching concern. All threats however are cumulative and should not be seen in isolation.
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