Are local extinctions and recolonizations continuing at the colder limits of marine fish distributions? Halobatrachus didactylus (Bloch & Schneider, 1801), a possible candidate

• Author(s): Robalo, Joana Isabel ; Crespo, Ana Maria Azambuja Farinha da Conceição Pereira ; Castilho, Rita ; Francisco, Sara Martins ; Amorim, Maria Clara Pessoa ; Almada, Vítor Carvalho
• Date: 2013
• Persistent ID: http://hdl.handle.net/10400.12/2377
• Origin: Repositório do ISPA - Instituto Universitário
• Document Type: Journal article
• Language: English
• Contributor(s): Repositório do ISPA

Description

In this paper, we compare the populations of the Lusitanian toadfish Halobatrachus didactylus along the Portuguese shore, using a putative fragment of the mitochondrial control region and the first intron of the S7 ribosomal protein gene. This demersal species ranges from the tropical West African coast to the Iberian Peninsula and the Mediterranean, having its northern limit in the Tagus River. For the putative control region, a single haplotype occurs in all fish from Tagus and Sado (the location immediately to the south) with a clear increase in diversity to the South, peaking at Algarve (south Portugal). The data seem to point to a very recent Holocenic colonization of Tagus and Sado from the South (possibly Algarve). We suggest that even small oscillations in sea surface temperature (SST) may cause local extinctions and subsequent recolonizations in populations of thermophilic fish that are at the cold limit of their distributions.