Do shortfin mako Isurus oxyrinchus hunt dolphins actively?

Area of Science:

• Marine Biology
• Ichthyology
• Cetacean Research

Background:

• Direct evidence of shark predation on cetaceans is limited.
• Distinguishing between scavenging and active hunting in shark-cetacean interactions is challenging.

Purpose of the Study:

• To document shark predation on dolphins.
• To investigate the feeding behavior of shortfin makos (Isurus oxyrinchus).
• To provide evidence of active predation by sharks on cetaceans.

Main Methods:

• Analysis of stomach contents from three shortfin mako sharks.
• Examination of dolphin (Tursiops aduncus and Stenella clymene) remains.
• Identification of premortem bite marks to infer predation activity.

Main Results:

• Dolphin remains were identified in the stomachs of three shortfin makos.
• Evidence suggested active predation in at least one case, indicated by bite marks.
• This is the first recorded instance of shortfin makos preying on Stenella clymene.

Conclusions:

• Shortfin makos exhibit opportunistic feeding behavior.
• Juvenile dolphins may be preyed upon by shortfin makos under specific ecological conditions.
• Findings contribute to understanding shark trophic ecology and predator-prey dynamics.