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

Klimley, A. Peter; Nelson, Donald R.

doi:10.1007/bf00310214

Cited by 134 publications

(121 citation statements)

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“…Our study presents long-term quantitative spatial and temporal information of a multi-species reef shark aggregation. Several hypotheses have been posed to explain reef shark aggregations, such as refuging (Klimley & Nelson 1984), predator avoidance (Wetherbee et al 2007), courtship, mating and pre-pupping (McKibben & Nelson 1986). Previous studies of daytime aggregations of reef-associated sharks suggested that aggregations were for behavioural thermoregulation to aid embryonic development or to avoid aggressive males (Economakis & Lobel 1998, Hight & Lowe 2007.…”

Section: Discussionmentioning

confidence: 99%

“…Aggregations have been observed in both adult and juvenile size classes for some species (e.g. Klimley & Nelson 1984, Duncan & Holland 2006 and often result in, or are attributable to, site fidelity and 'refuging' behaviour, where aggregations occur around a core daytime area and disperse at night (e.g. Klimley & Nelson 1984, Economakis & Lobel 1998, Hight & Lowe 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Klimley & Nelson 1984, Duncan & Holland 2006 and often result in, or are attributable to, site fidelity and 'refuging' behaviour, where aggregations occur around a core daytime area and disperse at night (e.g. Klimley & Nelson 1984, Economakis & Lobel 1998, Hight & Lowe 2007. Aggregations can also involve several species at the same time, although such inter-specific interactions have rarely been documented within the shallow waters of coral reefs (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Spatial and temporal movement patterns of a multi-species coastal reef shark aggregation

Speed¹,

Meekan²,

Field³

et al. 2011

Mar. Ecol. Prog. Ser.

103

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The quantification of spatial and temporal movement patterns of coral reef sharks is important to understand their role in reef communities and to aid the design of conservation strategies for this predatory guild. We observed 4 species of reef sharks aggregating in an inshore bay in the north of Western Australia for over 2 yr, using acoustic telemetry and visual censuses to examine how they partitioned this site in space and time. We fitted 58 sharks with acoustic transmitters: Carcharhinus melanopterus (36), C. amblyrhynchos (11), Negaprion acutidens (7) and Triaenodon obesus (4). Aggregations consisted primarily of C. melanopterus, although C. amblyrhynchos and N. acu tidens were often present. We observed aggregations by visual census in summer (maximum of 44 sharks). Detections were highest during warmer months (Sep to Mar) for all species, although some individuals showed year-round residency. C. melanopterus, C. amblyrhynchos and N. acutidens had strong diel patterns of attendance at the aggregation site. Peak daily detections occurred from 13:00 to 14:00 h local time for C. melanopterus and C. amblyrhynchos; juvenile C. melanopterus and N. acutidens peaked at 05:00 and 10:00 h, respectively. There was considerable spatial overlap of core areas of use (50% kernel density estimates) at the northern end of the bay by all species; the southern end was used primarily by C. melanopterus and N. acutidens. Aggregations of C. mela nop terus and C. amblyrhynchos consisted mainly of adult females, some of them pregnant. Courtship behaviour in C. melanopterus and T. obesus suggests that these aggregations are related to reproduction. All species displayed inter-annual site fidelity. The long-term presence of juvenile C. melanopterus and N. acutidens also suggests that this bay provides suitable conditions for younger age classes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spatial and temporal movement patterns of a multi-species coastal reef shark aggregation

Speed¹,

Meekan²,

Field³

et al. 2011

Mar. Ecol. Prog. Ser.

103

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“…However, many animals restrict their movement to areas much smaller than one might expect from observed levels of mobility. Site fidelity, the return to, and reuse of, a previously occupied location (Switzer 1993), has been noted in a number of oceanic and migratory sharks including white sharks (Carcharodon carcharias) (Klimley & Nelson 1984;Domeier & Nasby-Lucas 2007;Weng et al 2008) and is likely to have important impacts on the spatial dynamics of their populations. The causes and consequences of individual movement behaviour in the open ocean remain poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Philopatry and migration of Pacific white sharks

et al. 2009

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Advances in electronic tagging and genetic research are making it possible to discern population structure for pelagic marine predators once thought to be panmictic. However, reconciling migration patterns and gene flow to define the resolution of discrete population management units remains a major challenge, and a vital conservation priority for threatened species such as oceanic sharks. Many such species have been flagged for international protection, yet effective population assessments and management actions are hindered by lack of knowledge about the geographical extent and size of distinct populations. Combining satellite tagging, passive acoustic monitoring and genetics, we reveal how eastern Pacific white sharks ( Carcharodon carcharias ) adhere to a highly predictable migratory cycle. Individuals persistently return to the same network of coastal hotspots following distant oceanic migrations and comprise a population genetically distinct from previously identified phylogenetic clades. We hypothesize that this strong homing behaviour has maintained the separation of a northeastern Pacific population following a historical introduction from Australia/New Zealand migrants during the Late Pleistocene. Concordance between contemporary movement and genetic divergence based on mitochondrial DNA demonstrates a demographically independent management unit not previously recognized. This population's fidelity to discrete and predictable locations offers clear population assessment, monitoring and management options.

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“…Zebra sharks are considered nocturnal feeders (Compagno 2002), and formation of groups that take refuge in a small core area during daylight hours, then disperse for foraging in larger areas at dusk and night, is common in sharks (Klimley & Nelson 1984, Economakis & Lobel 1998, Sims et al 2005. This group formation may be an anti-predatory tactic while resting (Semeniuk & Dill 2005); it may facilitate social interaction and/or the location may act as a geographic landmark from which to forage (Klimley & Nelson 1984). Further research including localised movement, diet analyses and analysis of the reproductive cycle and mating is required to understand the function of this aggregation.…”

Section: Population Descriptionmentioning

confidence: 99%

Abundance and demography of a seasonal aggregation of zebra sharks Stegostoma fasciatum

Dudgeon¹,

Noad²,

Lanyon³

2008

Mar. Ecol. Prog. Ser.

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Seasonal aggregations commonly occur in the marine environment where typically wide-ranging organisms come together to exploit temporary resources or find conspecifics for mating events. The zebra shark Stegostoma fasciatum is a demersal carpet shark that aggregates over the austral summer months in the coastal waters of southeast Queensland, Australia. This study employed photo-identification and mark-recapture methods over a 3 yr period (2003 to 2006) to investigate the population size and structure of this aggregation. In total 327 individual zebra sharks were identified from 570 photographs. Numbered dart-tags on 15 zebra sharks were used to confirm that pigmentation patterns were unique and persistent in wild zebra sharks for up to 810 d. Pollock's robust design resulted in an annual population estimate of 458 individuals (95% CI = 298-618). The mean number of zebra sharks observed on a single day was 8 (± 8 SE) and the maximum number of zebra sharks seen on a single day was 34. In total, 27% of the sharks were sighted in more than one summer aggregation period and males had greater re-capture probabilities than females. The aggregation consisted exclusively of large (>1800 mm total length) adults with an overall female sex bias of 3.8:1 though sex-ratios varied temporally. Predictable visitation of large, presumably mature individuals to the site raises conservation concerns if aggregations of similar size and structure occur in regions where zebra sharks are fished.KEY WORDS: Mark-recapture · Seasonal aggregation · Zebra shark · Stegostoma fasciatum · Photo-identification · AbundanceResale or republication not permitted without written consent of the publisher

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

Cited by 134 publications

References 1 publication

Spatial and temporal movement patterns of a multi-species coastal reef shark aggregation

Spatial and temporal movement patterns of a multi-species coastal reef shark aggregation

Philopatry and migration of Pacific white sharks

Abundance and demography of a seasonal aggregation of zebra sharks Stegostoma fasciatum

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