The distribution and abundance of the endangered Knysna seahorse Hippocampus capensis (Pisces: Syngnathidae) in South African estuaries

Jacqueline F. Lockyear, Thomas Hecht, Horst Kaiser, Peter R. Teske

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

The occurrence, distribution and abundance of the endangered Knysna seahorse Hippocampus capensis in 10 estuaries on South Africa's warm temperate south coast, were investigated. Seahorses were found only in the Knysna, Swartvlei and Keurbooms estuaries. Sex ratios were even and, in most cases, more adults were found than juveniles. During the first year of study, seahorse densities were higher in the Swartvlei and Keurbooms estuaries than in the comparatively larger Knysna Estuary but, during the second year, seahorses were absent from the Keurbooms estuary, and the population size in the Swartvlei Estuary had decreased by more than 80%. These results suggest that, although the two smaller estuaries are able to support comparatively high densities of seahorses, population sizes may fluctuate considerably. Population size estimates for the Knysna Estuary were similar to those obtained in a previous study, suggesting that this estuary may represent a more stable environment and may thus be particularly important for the survival and conservation of this species.

Original languageEnglish
Pages (from-to)275-283
Number of pages9
JournalAfrican Journal of Aquatic Science
Volume31
Issue number2
DOIs
Publication statusPublished - 2006
Externally publishedYes

Keywords

  • Freshwater floods
  • Keurbooms Estuary
  • Knysna Estuary
  • Patchy distribution
  • Population size fluctuation
  • Submerged vegetation
  • Swartvlei Estuary

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

Fingerprint

Dive into the research topics of 'The distribution and abundance of the endangered Knysna seahorse Hippocampus capensis (Pisces: Syngnathidae) in South African estuaries'. Together they form a unique fingerprint.

Cite this