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Grey Nurse Shark Presentation by DPI
Tuesday 12June 2007

The Grey Nurse Shark population on the east coast of Australia is critically endangered (IUCN Red List of Threatened Species) with fewer than 500 individuals remaining. They are an inconic species whose loss would be a tragedy with unforeseen consequences to NSW's marine ecosystems.

The Department of Primary Industries (DPI) presented NPA~Marine supporters with an overview of past, current and future research on the east coast population of Grey Nurse Sharks for NPA members and volunteers.

The presentation provided a general overview of the biology, reproduction and population status of the grey nurse shark. It focussed on areas where past research has been conducted including distribution, abundance & population size. It additionally examined migratory movements, threats, population trajectories and genetics as well as discussing the current SEACAMS, pop-up archival tagging program and artificial breeding program.

Answers to the questions taken on notice by DPI are below:

Q: Have there been any investigations into sexual behaviour of GNS in relation to the temperature of the water?

Not at this stage

Q: Have there been any investigations and results regarding the reaction of tissues to injury and the pathology of this?

Yes and NSW DPI is currently investigating this.

Q: Have there been any abscesses observed?

GNS don't appear to form abscesses (following a strict definition of an abscess). This is a line of ongoing research in conjunction with vets.

Q: How has the gestation length been investigated, and what led to the conclusion of the 9-12 month gestation period as it seems highly variable?

In the USA, South Africa and more recently in part in Australia, the reproductive cycle and gestation period of local populations have been documented.

Variability arises from the possibility of female sperm storage and natural, individual variation in the duration of gestation.

Q: Can you provide a number of GNS affected by scoliosis? Or give an estimate of the percentage of the population affected by this condition.

Ten individually recognised sharks have been observed with kyphoscoliosis.

Q: How does scoliosis affect their survival?

It is likely that their survival will be substantially reduced.

Q: What is the status of the wobbegong shark? Has there been any research regarding the population status and the viability of the fishery?

Please see PhD by Dr Charlie Huveneers

Q: Is it known why there are 9 females and 3 males are dying from human induced causes when other ratios appear to be 1:1?

Not at this stage.