Recent research has shed light on the reasons behind large marine predators, such as tuna, sharks, and billfish, diving deep into the ocean’s depths. The study showed that these species frequently explore the mesopelagic zone, which spans from 200 meters (660 feet) to 1,000 meters (3,300 feet) below the surface. Electronic tags recorded the diving patterns of these fish species, revealing that they spent more time in this zone than previously believed.
The findings indicated that these predators often follow prey that feed near the surface at night and return to deeper waters during the day. Camrin Braun, an assistant scientist at the Woods Hole Oceanographic Institution, led the study and highlighted the significance of these animals’ deep diving habits across various top predators and oceanic regions.
Interestingly, the deep diving patterns of sharks and tunas, two groups with distinct evolutionary backgrounds and sensory systems, exhibited similarities in their utilization of the mesopelagic zone. Simon Thorrold, a fish ecologist at WHOI and a co-author of the study, noted the commonality of these behaviors among these two distinct groups Source.
Some behaviors observed in the study deviated from the expected feeding patterns, such as the swordfish’s extremely deep dives. This suggests that there could be other motivations behind these diving habits. As marine predators play a critical role in ocean ecosystems, understanding their diving patterns and behaviors may provide valuable insights into the overall health of the marine environment and its food chain.
By tapping into diverse sources of data to analyze various factors in the lives of predatory fishes (e.g., navigation, temperature, and acoustics), the research contributes to the field of marine biology and allows for better understanding of deep ocean ecology, including interactions in the twilight zone, deep ocean food webs, and the potential impact of climate change. This study can help in developing effective strategies to protect sea ecosystems and contribute towards human well-being.