Interesting facts – Understanding Orcas (Orcinus Orca)

Orcas (Orcinus orca) visit Plettenberg Bay sporadically, typically in small pods of 7–16 individuals, and are observed largely outside peak whale season. These apex predators display remarkable dietary flexibility, preying on dolphins, sharks, rays, and, in exceptional cases, surgically extracting shark livers, upending local marine food webs. While most encounters involve cruising and socializing near the bay’s edge, rare but dramatic predation events have driven significant ecological shifts, including the displacement of great white sharks.

Distribution and Seasonality

Plettenberg Bay sees its first orca incursions most years around late autumn to spring, with long intervals between visits. The first recorded sighting since November 2022 involved 16 whales, marking a notable return after a year‑long absence.

Local operators report that between June and October—when Southern right whales dominate—the probability of encountering orcas remains low, at under 10% on any given day Ocean Blue Adventures.

Social Structure and Schooling Behavior

Orca pods in Plettenberg Bay typically consist of 7 to 10 individuals, as documented recently by the crews of Ocean Blue Adventures. Globally, killer whales are known for their tight-knit social structures and strong matrilineal bonds. Records from South Africa (1963–2009) confirm similar group cohesion and seasonal movements along the Western Cape coast.

Adaptability is a key characteristic of their behavior; the pods observed here may switch from hunting dolphins to preying on sharks or rays, depending on the availability of prey.

Feeding Strategies and Prey Preferences

While dolphins remain typical prey, orcas in the Southern Cape display opportunistic feeding on sharks and rays. LiveScience reports that “liver‑eating” orcas have driven hundreds of great white sharks from parts of the Western Cape, suggesting dietary specialization on nutrient‑rich organs. Live Science
SANParks’ research further shows these whales can displace apex shark species from traditional aggregation sites, illustrating a shifting predator seascape in South African waters SANParks.

Rare Predation Events and Ecological Implications

The most striking behavior involves two males, “Port” and “Starboard,” documented removing shark livers with surgical precision—an unprecedented tactic that has altered local food chains and impacted shark‑based tourism The Washington Post.
In June 2023, a lone orca (“Starboard”) killed an 8.2‑foot great white shark in under two minutes, highlighting evolving hunting strategies and raising concerns for species like African penguins due to cascading ecological effects People.com.
One consequence has been the flight of great whites from key coastal areas, inadvertently boosting seal populations and affecting ecosystem balance The Guardian.

Conservation Outlook

These dynamic orca behaviors underscore the need for adaptive marine management in Plettenberg Bay. Continued monitoring by local research groups (e.g., ORCA Foundation) and integration of eco‑tourism with citizen science will be critical for understanding population trends, mitigating human–wildlife conflict, and preserving biodiversity along South Africa’s Garden Route.

Key References:

• Infrequent sightings and group sizes: Ocean Blue Adventures Plett Tourism
• Seasonal occurrence and distribution:  SANParks,  ResearchGate
• Adaptable feeding on dolphins, sharks, and rays: KnysnaPlettHerald, Live Science
• Exceptional predation events (Port & Starboard): Washington Post The Washington Post, People.com
• Ecological impacts and trophic cascades: The Guardian The Guardian