A new study by the MMF and research collaborators has been published in the journal Marine Ecology Progress Series, investigating the diving behavior of black and striped marlin. The authors, and participating sport fishing guides, deployed satellite tags on marlin off Kenya to track their movements. This is the first study into the diving behavior of these species in the Indian Ocean and highlights that the two marlin species have differences in their diving behavior, which allow them to both be successful, even when sharing the same habitat.

Black and striped marlin reached maximum dive depths of over 460 m, temperatures as low as 10 °C, and dove into waters with low oxygen concentration, but they both spent most of their time in shallower, warmer waters. Striped marlin descended deeper more frequently than black marlin, but they also spent more time in the top 5 m of the water column. Dr. Chris Rohner, lead author of the study and a Principal Scientist with MMF, explains, “striped marlin often hunt squid in deep water. After a deep dive into cold water, they have to warm up at the surface before they resume hunting. In contrast, black marlin largely stayed closer to the surface, in the warmer mixed layer, where they were likely hunting fish.”