Meeting Abstract
The Australian giant cuttlefish, Sepia apama, is the world’s largest cuttlefish species. Known for its bright color displays, S. apama comprises populations that are found near the rocky reefs, kelp forests, sea-grass beds, sand and muddy seafloors of Southern Australia to a depth of up to 100 m. Their typical breeding behavior involves pair or small groups. However, the population that occupies the Upper Spencer Gulf area is known to breed in large aggregations, which has led to speculation that this population may be a separate species or sub-species. Given that the conservation status of S. apama is near threatened, it is essential to determine the number of species present. This study uses molecular and phylogenetic tools to investigate the relationships between different populations and determine if new species designations are warranted. Tissue samples from 17 cuttlefish were collected in 4 distinct geographical locations: in and around the Sydney Harbor, from Upper Spencer Gulf, from Geographe Bay, and from Houtman Abrolhos (islands). We obtained genetic sequence data for the mitochondrial CO1 and 16S rRNA gene regions and used this data to build phylogenetic trees and calculate % sequence differences across individuals from all populations. Preliminary analyses distinct groups: one along south and southeastern Australia from the Upper Spencer Gulf in the north to Geographe Bay in the southwest and a second in western Australia off of the Houtman Abrolhos. These findings suggest that individuals of S. apama, with the exception of those found in Western Australia, are somehow overcoming geographical distance and their poor swimming abilities to intermix. Further morphological examination is warranted to determine the taxonomic rank of the distinct western population.
