Observations of a species‐record deep dive by a central Pacific female scalloped hammerhead shark (Sphyrna lewini)

Abstract

A female scalloped hammerhead shark (Sphyrna lewini) conducted a species record deep dive to 1240 m in coastal‐pelagic waters off Hawaii Island. This extends the deepest known depth range of the species by over 200 m (650 ft) and highlights the question of the extent to which deep‐diving activity is mediated by physiological constraints, such as temperature and oxygen availability.

Diel Vertical Habitat Use Observations of a Scalloped Hammerhead and a Bigeye Thresher in the Northern Gulf of Mexico

“…Similar behavior was observed for this species satellite tagged in the tropical eastern Pacific, where scalloped hammerheads spent most of the time near surface waters, specifically above 100 m [31]. However, it is important to note that Bessudo et al (2011) [31] and Hoffmayer et al (2013) [33] found scalloped hammerheads are able to make extensive dives reaching depths of approximately 1000 m, where temperatures can reach 4 • C. Most recently, Anderson et al (2022) [47] noted a new diving record for the species in coastal-pelagic waters of Hawai'i where a scalloped hammerhead reached a depth of 1240 m. Previous research has described ways in which scalloped hammerheads increase physiological efficiency by demonstrating a "breath holding" technique that allows them to compensate and maintain a warm body while they actively pursue prey in deeper, colder depths, and by swimming on their sides to possibly help reduce the cost of transport [48,49]. However, the scalloped hammerhead described here did not seem to reach depths or temperatures that required either of these strategies.…”

Renewed occurrence of schooling scalloped hammerhead (Sphyrna lewini) and of great hammerhead (S. mokarran) sharks in the Cayman Islands

“…The literature indicates that S. lewini exploit a wide range of depths, mostly between 0 and 275 m (Moore and Gates, 2015), with the maximum recorded depth being 1240 m (Anderson et al, 2022). For example Hoffmayer et al (2013) satellite tagged a 240 cm (TL) female S. lewini off the Mississippi River and monitored her for 27 d, during which time she was consistently between 0 and 228 m during the day, but from 0 to 964 m at night, when most dives were to >700 m. In the western Gulf of Mexico, Wells et al (2018) found that 33 satellite tagged S. lewini preferred mid to outer continental shelf within a 200 m isobath.…”