Short Communication

Decline of Terebralia palustris in South African mangroves

  • JL Raw
  • R Perissinotto
  • RH Taylor
  • NAF Miranda
  • N Peer

Abstract

Terebralia palustris (Linnaeus, 1767), the giant mangrove whelk, is a prominent component of mangrove ecosystem malacofauna in the Indo-West-Pacific region. On the east coast of Africa, the range of T. palustris extends from Kenya to the south-eastern region of South Africa. Here we confirm reports that, in the past three decades, South African populations of T. palustris have declined. Terebralia palustris was recorded from only two estuarine mangrove forests during a survey conducted in 2013/2014, compared with six estuaries in the mid-20th century. At Kosi Bay, the average density was 186 ind. m−2 (SD 106) in comparison to only 7.1 ind. m−2 (SD 2.5) at Durban Bay. Additionally, the average shell height of individuals at Durban Bay (60.3 mm; SD 13.6) was larger than at Kosi Bay (31.84 mm; SD 16.09), indicating the absence of juvenile snails at Durban. In South Africa there have been no previous ecological assessments for T. palustris and, aside from one detailed survey in the early 1960s, most of the occurrence records are vague and incomplete. The ultimate causes for the decline of this charismatic gastropod in South Africa are unknown, although habitat loss and degradation are suspected. Further research is urgently required, particularly into aspects concerning its disappearance at the limit of its global distribution.

Keywords: distribution, estuarine ecosystems, extirpation, giant mangrove whelk, subtropical

African Journal of Marine Science 2014, 36(4): 517–522

Author Biographies

JL Raw
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
R Perissinotto
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa; School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
RH Taylor
School of Hydrology, University of Zululand, KwaDlangezwa, South Africa
NAF Miranda
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
N Peer
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
Published
2015-04-02
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X