Diving behaviour of whale sharks in relation to a predictable food pulse

Graham, Rachel T.; Roberts, Callum M.; Smart, James C. R.

doi:10.1098/rsif.2005.0082

Cited by 107 publications

(108 citation statements)

References 21 publications

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“…Godo & Michalsen 2000, Righton et al 2001). An exception is the recent use of spectral analysis for distinguishing between normal and reverse diel vertical migration in planktivorous sharks (Graham et al 2006). Various methods for classifying dives for airbreathing vertebrates have been used, often involving multi-variant techniques that summarise the duration, depth and shape of dive profiles (Schreer et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Vertical movements of North Sea cod

Hobson

Righton²,

Metcalfe³

et al. 2007

Mar. Ecol. Prog. Ser.

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Various air-breathing marine vertebrates such as seals, turtles and seabirds show distinct patterns of diving behaviour. For fish, the distinction between different vertical behaviours is often less clear-cut, as there are no surface intervals to differentiate between dives. Using data from acoustic tags (n = 23) and archival depth recorders attached to cod Gadus morhua (n = 92) in the southern North Sea, we developed a quantitative method of classifying vertical movements in order to facilitate an objective comparison of the behaviour of different individuals. This method expands the utilisation of data from data storage tags, with the potential for a better understanding of fish behaviour and enhanced individual based behaviour for improved ecosystem modelling. We found that cod were closely associated with the seabed for 90% of the time, although they showed distinct seasonal and spatial patterns in behaviour. For example, cod tagged in the southern North Sea exhibited high rates of vertical movement in spring and autumn that were probably associated with migration, while the vertical movements of resident cod in other areas were much less extensive and were probably related to foraging or spawning behaviours. The full reasons underlying spatial and temporal behavioural plasticity by cod in the North Sea warrant further investigation.

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Section: Discussionmentioning

confidence: 99%

Vertical movements of North Sea cod

Hobson

Righton²,

Metcalfe³

et al. 2007

Mar. Ecol. Prog. Ser.

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“…In the present study, sharks often performed deep, fast dives below 300 m in offshore locations. Graham et al (2006) found that deep diving in whale sharks was non-randomly distributed, being more regular when a predictable food source was apparently no longer available. A similar pattern has been observed in a leatherback turtle, with more deep dives being performed after the turtle left a suitable prey field (Doyle et al 2008).…”

Section: Vertical Movements and Behaviourmentioning

confidence: 99%

Short-term movements and diving behaviour of satellite-tracked blue sharks Prionace glauca in the northeastern Atlantic Ocean

Queiroz¹,

Humphries²,

Noble³

et al. 2010

Mar. Ecol. Prog. Ser.

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Shifts in the movement, activity or behaviour of individual animals in relation to changing environmental landscapes play an important role in determining re-distribution patterns of populations. Such spatial dynamics are poorly understood for pelagic sharks despite the decline of many species due to overfishing. Satellite-linked archival transmitters were used to record the movements of blue sharks Prionace glauca for the first time in the northeast Atlantic. A total of 256 tracking days were recorded, with sharks covering an estimated minimum distance of 11 432 km. Generally, blue sharks displayed wide-ranging southward movements away from the tagging areas (English Channel, southern Portugal and the Azores Islands), with juvenile sharks displaying less site fidelity than previously suggested from other methods. Vertical movements ranged from the surface to a maximum depth of 696 m, and water temperatures varied from 10.6 to 24.6°C. Shifts in both thermal and depth-use patterns were detected, with tracked sharks displaying behavioural variability correlated with the environment, both within and between individuals. Patterns of behaviour in coastal areas were generally linked to the thermal structure of the water column; sharks displayed some preference for surface layers in thermally stratified waters, but displayed less regular behaviour in wellmixed or weakly stratified waters. In offshore locations, sharks usually adopted either a surfaceoriented or a depth-oriented diving pattern, often switching between both in response to probable changes in prey distribution or prey type when in deeper water. Fishing-induced mortality of tracked sharks was approximately 10% during the period of 13 to 70 d post-tagging. Our results indicate a variety of short and longer range movements of juvenile and sub-adult blue sharks with respect to time and environment in the northeast Atlantic, which suggests complex spatial dynamics and population structuring in this exploited species.

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“…Whale sharks are commonly observed at the ocean surface; however, they have recently been tracked to dive to bathypelagic (>1000 m) depths (Graham et al 2006, Brunnschweiler & Sims 2011. While whale sharks spend a lot of their time in the epipelagic zone, these deep dives are intriguing and have been hypothesised to be foraging related (Brunnschweiler & Sims 2011).…”

Section: Feeding At Depthmentioning

confidence: 99%