Black Fillet Project
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Research

Our findings

Preliminary findings...

A preliminary investigation was undertaken on the basis of a few samples from a flathead caught by recreational fishers in March 2010 and a few sampled in September 2011.
The flathead appeared to have melanin deposits in the skeletal muscles (around individual muscle fibres) and some pigment was associated with blood vessels.

In 2015/16 two Honours projects, one in IMAS and one in Chemistry, investigated the possible causes of the melanisation.  Zinc levels were higher in the muscle of melanised fish and has well known association with melanin in other animals. No parasites were present in the muscle of the affected fish. A journal article from those projects is available here.

In 2018/19, in another IMAS Honours project recreational fishers were surveyed to assess the extent of muscle melanisation in marine fish in Tasmania. The vast majority of respondents indicated that they had observed melanisation in at least some of the sand flathead they had caught. The findings of this survey can be found here.

That Honours project included studies of other aspects of melanisation, confirming that the melanisation of flathead muscle was most severe in Deceitful Cove, Tamar Estuary.  It was suggested that both eumelanin and pheomelanin were involved in this phenomenon.  Melanisation was not, however, related to fish condition, age, sex, maturation stage, fish weight, fish length or size of melano-macrophage centres in the liver or spleen. A journal article about this project is available here.

Muscle melanisation in sand flathead is currently the subject of an ongoing PhD research in the School of Natural Sciences (Chemistry) and IMAS, University of Tasmania.

A list of published reports about fish health and melanisation in general is available at this here.

In Tasmania, sand flathead (Platycephalus bassensis) is one of the most important finfish species with significant recreational value.
This species alone represents almost two thirds of the total recreational finfish catch numbers, with approximately 2 million fish caught annually in Tasmania.
Despite the importance and abundance of
these fish species in Tasmanian waters, there
is little information regarding the health
status of this species.
Because flathead are abundant
and exhibit strong site fidelity,
the species has been used as ‘sentinel’ species
to monitor pollution in estuaries, for
example in the Derwent and Tamar Estuaries in Tasmania and Port Philip Bay in Victoria. The high levels of pollutants in flathead from some Tasmanian estuaries has been recognised for many years.
If you've ever seen this in Sand Flathead or any other fish that you have caught around Tasmania
Let Us Know
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Research for the future of sustainable fishing in and around Tasmania 
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