Our Transitioning National Fish Is A Cougar

Video highlights from Only In OZ

Barramundi are renowned for their mouth-watering eating, were named by a marketing campaign, will dine out on anything they find including each other – and they change sex from male to female as a natural part of their life cycle.

Long a favourite of Aussie diners, known for its meaty texture and buttery flavour, “barra” as it is known locally, is internationally referred to as Asian sea bass, giant perch or giant sea perch.

Some time in the 1980s a marketing guru who probably sported a ponytail – the 80s equivalent of a manbun - decided to borrow an Aboriginal word from the Rockhampton area meaning “large scale river fish”.

And the rest as they say is marketing history.

The barramundi’s lifecycle includes freshwater, estuarine and marine phases. In the wet season (October to April), sexually mature adults migrate from freshwater to coastal estuaries and river mouths to spawn (release sperm and eggs).

Spawning usually takes place after the full moon or new moon, when tidal activity is strongest.

A large female can produce up to 40 million eggs during the spawning season. Despite such high production, more than 90 per cent of larvae and juveniles die in the first few weeks or months.

High tides and wet season floods wash eggs and larvae into mangrove and tidal habitats.

The juvenile fish then migrate into rivers and freshwater billabongs, where they develop into adults over the course of three or four years.

When the fish become sexually mature (at three to five years of age) they migrate back to the saltwater to spawn and the lifecycle begins again.

The species is sequentially hermaphroditic, with most maturing as males and becoming female after at least one spawning season; most of the larger specimens are therefore female.

This also means of course that barra ladies are the cougars of the aquatic world – female fishes can only be courted by younger males.

It turns out about about two per cent of fish species display some kind of hermaphroditism: that’s 500 different species worldwide.

Some like the kobudai change routinely from female to male.

Others, like the clownfish, do the opposite, from male to female.

Still others can switch back and forth depending on the circumstance, such as a variety of coral-dwelling gobies.

And at least one species, the mangrove killifish, lives a fully bisexual hermaphroditic existence, self-fertilising for their entire reproductive lives, so make sure you carry a bucket of cold water around if they’re nearby.

Discuss this article


Never miss a Nat Geo moment

Your email address
We use our own and third-party cookies to improve our services, personalise your advertising and remember your preferences. If you continue browsing, or click on the accept button on this banner, we understand that you accept the use of cookies on our website. For more information visit our Cookies Policy AcceptClose cookie policy overlay