Molecular phylogeny and population genetic structure of the shallow-water spiny lobster Panulirus homarus in the South West Indian Ocean region : implications for management.
Year: 2013
Type: dissertation
Abstract: The scalloped spiny lobster, Panulirus homarus has a subspecies trio that are widely \ndistributed in shallow-water habitats in the South West Indian Ocean. Subspecies are \ndefined by differences in colour and abdominal sculptural pattern. A red variety with the \nmegasculptural carapace pattern, P. h. rubellus is distributed along the south east coast \nof Africa and Madagascar, where they are endemic. Along the African coast P. h. \nrubellus stocks traverse political boundaries, Mozambique and South Africa. This \nproject aimed to facilitate regional fisheries management of shared stocks by employing \ngenetic tools to determine whether stocks (or populations) are indeed shared between \ncountries. Lobster samples were collected from seven localities throughout the east \nAfrican coast. The mitochondrial cyctochrome c oxidase subunit 1 region was \nsequenced to assess the genetic diversity 1) between different subspecies, P. h. homarus \nand P. h. rubellus and 2) between populations of P. h. rubellus across its African \ndistribution range. Using DNA barcoding methods, genetic diversity was also found \nbetween morphologically distinct subspecies, Panulirus homarus homarus and P. h. \nrubellus which differed genetically by ca. 2-3% in sequence divergence. Both \nsubspecies were monophyletic relative to the out-group taxa and formed well supported \nsister clades (BI: 1.00, ML: 93%, P: 100%, NJ: 100%). The distribution of P. h. \nrubellus along the African coast occurs adjacent to different current regimes and \ntherefore varied larval transport modes (i.e. Agulhas Current and inshore countercurrents \n along the Eastern Cape). This may have driven the formation of subpopulations \n(ΦPT = 0.104, p = 0.010) which differ by ca. 1.7% in sequence difference. The pattern of \ngene flow of populations of P. h. rubellus lends support to the Agulhas Current being a \nmajor mode of larval transport as well as corroborates previous abundance and \ndistribution records. Time since population expansion estimates for the P. h. homarus \nand P. h. rubellus subspecies as well as for the P. h. rubellus subpopulations dated back \nto the mid-Holocene Epoch in accordance with a warmer, more stable marine \nenvironment. Genetically distinct subspecies of P. homarus as well as differentiated \nsubpopulations of P. h. rubellus calls for a re-visit of the current collective management \nof P. homarus as well as P. h. rubellus as a single genetic stock along the south east \nAfrican coast.
Author: Mageshnee Mayshree. Reddy
Language: English
Subfield: Genetics
Domain: Life Sciences
SDG: Life below water
Open Access status: green
OpenAlex ID: W2163368653