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Redmap results summary

Redmap has been up and running for almost 19 months now and many of you have contributed details and awesome photos of sightings, many of which you can see on the website. So far, we’ve received a total of approximately 270 sightings of 64 species from over 120 people! Here is a summary of our results for some commonly reported species on the Redmap list (as of March 2011). Watch this space for more results soon!

Verified sightings are those that included a photo that was examined by an expert and the species ID was confirmed. 'Out of range over winter' are sightings that have been reported from June to August. We are particularly interested in sightings made over winter - if we get a large number of verified sightings of a particular species throughout the cooler winter months, over a number of years, then that is stronger evidence of a range extension - in contrast to a species that may only visit Tassie every now again again over summer while its nice and warm.

 If you would like a copy of the full species list, with descriptions to print out and keep it is avaliable here.

Luderick (Girella tricuspidata)

Eastern rock lobster (Jasus verreauxi)

Maori wrasse (Ophthalmolepis lineolatus)

White-ear (Parma microlepis)

Yellowtail kingfish (Seriola lalandi)

So what do the sightings mean?

Redmap sightings received so far are spread across 16 main species. You might be wondering if this means the species involved have undergone range extensions, and if that is linked to warmer waters off our coast. The answer is … maybe!

Detecting change in ecological systems is genuinely difficult, and in marine systems this is particularly challenging. Species distributions are often limited by physical factors, like water temperature, but whether or not a species actually does live in a particular place can depend on many other factors like food availability, predators present, and competition with other species that have similar food or habitat requirements. Also, the boundaries of a species’ distribution are not ‘fixed’ and include a level of natural variation. It is also quite common to see individuals of a particular species that are found outside of their usual distribution but don’t become a permanent part of the region they are visiting.

So, this means that our monitoring needs to be conducted over a long enough timeframe for change to be detected over and above natural variation in the system – and this is where the fishers and divers of Tasmania come in! Thanks to all the Tasmanian fishers and divers that are helping with this challenge by sending in their observations!

For more information on range shifts see the Resources section.

Analysing your Redmap contributions

The observations you make whilst out enjoying the great fishing and diving Tassie has to offer are really important. In just over a year, your Redmap sightings have made valuable contributions to scientific journal articles, and soon we’ll be producing a qualitative report card so that you can see at a glance which species are being reported in Tasmanian waters and what those reports might mean.  Over the longer term we will be developing a way to determine if the species reported on Redmap have undergone statistically significant extensions or shifts in their geographical range.