A fourth new record for Sydney Harbour!

A huge thank you goes to Kim Dinh who recently added an observation of a 3 cm long juvenile Blackspotted Puffer, Arothron nigropunctatus, photographed in Sydney Harbour. (left image).

The species had not previously been recorded from the Harbour. The Sydney Harbour Fish list, which now contains 595 species. has been updated.

Kim's observation, which was made on the 9th April 2018, was followed up by a second sighting of the same fish 12 days later*. Kim reported that the fish had grown to about 5cm in length.

The Blackspotted Puffer is a tropical species. In Australia, it occurs from northwestern Western Australia, around the tropical north of the country, and on the east coast south to the Shoalhaven River, New South Wales. The species has previously been photographed south of Sydney by Andrew Trevor-Jones (right image), but Kim's observation is the first time it has been documented from within the harbour.

Since Australasian Fishes went online in October 2016, 3 species have been added to the Sydney Harbour List in addition to Kim's recent observation.

*To view Kim's second image, click on the left image above and wait for the observation page to display. Next, click on the second thumbnail image visible under the large image.

Publicado el 30 de abril de 2018 a las 05:38 AM por

markmcg

Comentarios

As warming continues are we likely to see more tropical species venturing further south more regularly, or even establishing where previously they had not lived?

Anotado por adammyates hace casi 6 años

Hi @adammyates. Yes, I agree with you. I'm pleased that this sort of information is being documented by Australasian Fishes. There have been multiple observations of fishes photographed outside their recognised ranges. I'm sure there will be many to come.

Anotado por markmcg hace casi 6 años

@markmcg There is a solitary thalassoma purpureum i hope to get a picture of in the Harbour in the upcoming weeks.

Anotado por henrick hace casi 6 años

@henrick "Everlasting fame" awaits you. Good luck. That would bring the count that little bit closer to 600. :)

Anotado por markmcg hace casi 6 años

FYI @jemina and @grettapecl

Anotado por markmcg hace casi 6 años

nice one @kdinh123 !

Anotado por johnturnbull hace casi 6 años

Thanks Mark; I will not make headlines by agreeing with you about global warming but I agree, and let us all hope the wise person who coined 'Where there's life there's hope' was on the money and lived next door to the wise person who coined 'Necessity is the mother of invention'(!?)

Anotado por davemmdave hace casi 6 años

@adammyates the answer is yes, but also not really, but maybe in the longer term.

In the last 20 years tropical species have been recorded more often, and further south on the east coast of Australia. That's a fact.

However the Australian Museum contains specimens from Sydney Harbour of coral trout from over 60 years ago, commercial records from the south coast of NSW indicate good runs of spotted mackerel around 40 years ago, and so on and so forth.

Many range extensions are of juveniles. New record, fair enough, but is that ecologically significant.... who knows.

For me, the true indicator of spatial shifts in species compositions is medium to long term permanence. By that I mean the establishment of adult populations that are capable of self-replenishment.

A good example is the Black Cod, Epinephelus daemelii. This species was abundant in NSW, including southern regions, but fishing reduced those populations, especially in the south, to very low numbers by the 1980's. However NSW Fisheries examination of BC speared in comps revealed that BC in southern regions were not reproductively active. A "dead" population in effect, relying on larval replenishment from breeding populations further north.

Currently we are seeing good numbers of juveniles of BC on the south coast. Is this a good thing, or are locally endemic predatory fish of similar size being negatively impacted?

The same question can be asked of the tropical arrivals we are seeing now. Are these butterflyfish going to form long term, stable populations which form reproductive units, or will they simply be food for whatever can eat them come winter?

Anotado por sascha_schulz hace casi 6 años

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