Genetics and evolution
• Genetic studies have determined the extent of connectivity in a range of recreationally and commercially important fish and crustacean species.
• Emphasis is placed on testing the stage or stages of the life history at which most dispersal takes place.
• While some species are genetically homogeneous over their range, others comprise genetically distinct groups that reflect the influence of coastal morphology.
Evolutionary implications of climate change
• Southern Australian coastal waters are providing an excellent model for testing hypotheses regarding the effects of glacial and interglacial cycles on the demographic history of resident species.
• Results for some species are consistent with paleoenvironmental data, which suggest that populations to the west of Bass Strait are more heavily impacted by glacial periods than those to the east.
Genetic aspects of restocking
• Genetic studies are being conducted for restocking programmes aimed at replenishing depleted stocks to investigate the genetic implications of such restocking and thus ensure best practise in these programmes.
• A study showed little genetic difference between the cultured fish and wild fish in a unique restocking programme for an estuarine species.
For further information, please contact Dr Jennie Chaplin on 93602294 or J.Chaplin@murdoch.edu.au .
• Studies have been carried out by centre staff on many aspects of lampreys for over 50 years
• Lampreys are of importance because they are one of the only two surviving groups of the early agnathan (jawless) stage in evolution, the most abundant vertebrate in many rivers and have considerable cultural significance for certain indigenous populations. The populations of some species are also threatened in a number of regions and have contributed to the decline of particular fish stocks.
• The phylogenetic relationships between the 37 northern hemisphere and four species of southern hemisphere lampreys have been explored using morphological and molecular data. Current studies are estimating times of divergence of the main lamprey taxa and the factors that influenced the separations.
• Many studies have explored the relationship between the anadromous and freshwater parasitic species and their non-parasitic derivatives and hypothesised as to the changes that occurred during such evolution and the selection pressures involved.
• As the southern hemisphere lamprey Geotria australis does not feed during its 15 month upstream spawning migration, it is a particularly good model for exploring, from a physiological and biochemical perspective, how a species can accumulate sufficient reserves for such a protracted non-trophic period and utilise those resources for swimming upstream and developing mature gonads.
• Comparisons of the dentition and ancillary feeding mechanisms and analysis of gut contents have demonstrated that lampreys mainly feed either on blood or muscle tissue and elucidated the particular adaptations associated with each of those feeding modes.