Dataset Information

Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa.

ABSTRACT: Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195-283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n?=?16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean ?=?533 km) with eight of these sharks returning to the study site. During migration, individuals exhibited rates of movement between 2 and 59 km x d(-1) (mean?=?17.58 km x d(-1)) and were recorded travelling annual distances of between 450 and 3760 km (mean?=?1163 km). Migration towards lower latitudes primarily took place in austral spring and winter and there was a significant negative correlation between residency and mean monthly sea temperature at the study site. This suggested that seasonal change is the primary driver behind migration events but further investigation is required to assess how foraging and reproductive activity may influence residency patterns and migration. Results from this study highlight the need for further understanding of bull shark migration dynamics and suggest that effective conservation strategies for this vulnerable species necessitate the incorporation of congruent trans-boundary policies over large spatial scales.

SUBMITTER: Daly R

PROVIDER: S-EPMC4190266 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa.

Daly Ryan R Smale Malcolm J MJ Cowley Paul D PD Froneman Pierre W PW

PloS one 20141008 10

Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195-283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. ...[more]

PMID: 25295972

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Project description:BackgroundHunter-gatherer lifestyles dominated the southern African landscape up to ~ 2000 years ago, when herding and farming groups started to arrive in the area. First, herding and livestock, likely of East African origin, appeared in southern Africa, preceding the arrival of the large-scale Bantu-speaking agro-pastoralist expansion that introduced West African-related genetic ancestry into the area. Present-day Khoekhoe-speaking Namaqua (or Nama in short) pastoralists show high proportions of East African admixture, linking the East African ancestry with Khoekhoe herders. Most other historical Khoekhoe populations have, however, disappeared over the last few centuries and their contribution to the genetic structure of present-day populations is not well understood. In our study, we analyzed genome-wide autosomal and full mitochondrial data from a population who trace their ancestry to the Khoekhoe-speaking Hessequa herders from the southern Cape region of what is now South Africa.ResultsWe generated genome-wide data from 162 individuals and mitochondrial DNA data of a subset of 87 individuals, sampled in the Western Cape Province, South Africa, where the Hessequa population once lived. Using available comparative data from Khoe-speaking and related groups, we aligned genetic date estimates and admixture proportions to the archaeological proposed dates and routes for the arrival of the East African pastoralists in southern Africa. We identified several Afro-Asiatic-speaking pastoralist groups from Ethiopia and Tanzania who share high affinities with the East African ancestry present in southern Africa. We also found that the East African pastoralist expansion was heavily male-biased, akin to a pastoralist migration previously observed on the genetic level in ancient Europe, by which Pontic-Caspian Steppe pastoralist groups represented by the Yamnaya culture spread across the Eurasian continent during the late Neolithic/Bronze Age.ConclusionWe propose that pastoralism in southern Africa arrived through male-biased migration of an East African Afro-Asiatic-related group(s) who introduced new subsistence and livestock practices to local southern African hunter-gatherers. Our results add to the understanding of historical human migration and mobility in Africa, connected to the spread of food-producing and livestock practices.

Dataset Information

Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa.

Publications

Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa.

Similar Datasets

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