Diel movement patterns of the scalloped hammerhead shark (Sphyrna lewini) in relation to El Bajo Espiritu Santo: a refuging central-position social system

Understanding distribution ranges and the daily movement patterns of pelagic fishes are key aspects for the establishment and planning of protected areas for their conservation. In this study the vertical and horizontal movements of scalloped hammerhead sharks, Sphyrna lewini, were recorded in Malpelo and Cocos Island using satellite telemetry. Nine sharks were tagged with satellite transmitters during March 2006, 2007 and 2008 at Malpelo Island, and three hammerhead sharks were tagged at Cocos Island in June 2008. The sharks moved between islands in the Tropical Eastern Pacific and made regional movements from Malpelo to the south of Cocos and around the Malpelo ridge. When away from the island, sharks made infrequent nocturnal short dives down to 1000 m where temperatures were as low as 4 °C. For a shark that was tracked for five months, results indicated significant differences between the time spent at different depth ranges, as well as an interaction between depth, water layers, and the time of the day. The shark swam mostly at surface waters (0-10 m) during the cold water season, and spent more time at the deepest depth range (>100 m) during nigh time. Further long-term studies on shark movement patterns are required for a better management of this highly mobile and vulnerable species.

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New insights into the migration patterns of the scalloped hammerhead shark Sphyrna lewini based on vertebral microchemistry

Marine Biology ◽

10.1007/s00227-020-3668-0 ◽

2020 ◽

Vol 167 (5) ◽

Cited By ~ 1

Author(s):

Claire Coiraton ◽

Felipe Amezcua ◽

James T. Ketchum

Keyword(s):

Migration Patterns ◽

Sphyrna Lewini ◽

Hammerhead Shark ◽

Scalloped Hammerhead

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Feeding strategy of the night shark (Carcharhinus signatus) and scalloped hammerhead shark (Sphyrna lewini) near seamounts off northeastern Brazil

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592009000200002 ◽

2009 ◽

Vol 57 (2) ◽

pp. 97-104 ◽

Cited By ~ 8

Author(s):

Teodoro Vaske Júnior ◽

Carolus Maria Vooren ◽

Rosangela Paula Lessa

Keyword(s):

Food Web ◽

Deep Water ◽

Feeding Strategy ◽

Northeastern Brazil ◽

Sphyrna Lewini ◽

Marine Food Web ◽

Hammerhead Shark ◽

Scalloped Hammerhead ◽

Marine Food

A total of 425 stomachs of night shark (Carcharhinus signatus), and 98 stomachs of scalloped hammerhead shark (Sphyrna lewini), from longline and surface gillneters near seamounts off northeastern Brazil, were analysed between 1992 and 1999. Both predators prey upon reef and benthopelagic fishes, migrant cephalopods and deep water crustaceans, showing similar feeding niches (Schoener Index T=0.75). The great prey richness of the diets may reflect the fact that the marine food web for these species is very extensive in this region. Due to the concentration for feeding of both predators in the seamounts, intense fisheries should be monitored to avoid localised depletions.

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Age and growth of the Scalloped Hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834), from the southern Brazilian coast

Brazilian Journal of Biology ◽

10.1590/s1519-69842011000400022 ◽

2011 ◽

Vol 71 (3) ◽

pp. 755-761 ◽

Cited By ~ 9

Author(s):

JE. Kotas ◽

V. Mastrochirico ◽

M. Petrere Junior

Keyword(s):

Growth Parameters ◽

Growth Models ◽

Calculated Data ◽

Age And Growth ◽

Brazilian Coast ◽

Sphyrna Lewini ◽

Hammerhead Shark ◽

Scalloped Hammerhead ◽

Marginal Increment ◽

Best Fit

Age and growth studies for the scalloped hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834) caught along the southern Brazilian coast, were based on ring measurements of vertebrae sections of 115 males, 116 females and 14 unknown sexed sharks between 48 and 344 cm total length (TL). The von Bertalanffy growth models were best fit using back-calculated data. The growth parameters obtained for males, were L∞ = 266 cm; K = 0.05/year; L0 = 47 cm. For females, L∞ = 300 cm; K = 0.05/year; L0 = 51 cm. An adult female reached 217 cm TL and was 31.5 years old. On the other hand, an adult male was 29.5 years old and measured 234 cm TL. Longevity estimate for males and females was 55 years. Therefore, S. lewini is a long-lived fish. Ageing precision, based on the IAPE index, was 5.6%. Marginal Increment analysis based on MIR index from hammerheads smaller than 105 cm, compared with the percentual of opaque and hyaline bands found per month ageing whole vertebrae, showed an annual ring formation, i.e., in winter.

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