Fish catch reveals prized species moving south

A fishing expedition on the north coast of New South Wales has made an unexpected catch for a marine researcher from Southern Cross University.

When brothers Benjamin and Daniel Mos went fishing over the summer, the couple didn’t expect their catch to be anything more than a photo op or dinner. Instead, the fish they caught and released, commonly known as the barred javelin, prompted them to write a scientific paper now published in Fish Biology Journal.

According to Dr. Benjamin Mos, a marine biologist based at the National Marine Science Center at Southern Cross University, the crossed-out javelin was rare to find in New South Wales waters.

“While this species is probably well known to anglers in Queensland, it’s not something we typically find here. We had to scour a few fish books and websites to identify our specimens,” said Dr Mos.

“Our catches in late 2021 and early 2022 are the most southerly records for the barred javelin reported to date. And there may be more in the region.

“At the end of May 2022, we saw messages on social media about a barred javelin captured at Deep Creek, which is just north of the Nambucca River where we found our specimens.”

The species has previously been sighted in the Richmond River and Clarence River systems on the New South Wales north coast, about 200 kilometers north of the Nambucca River, where the last specimens were discovered.

It is unclear whether the arrival of the crossed-out javelin this far south in New South Wales was due to changing ocean conditions.

“It is possible that the sightings this far south are a one-time event. However, our sightings match a broader pattern occurring in the waters off southeastern Australia, indicating a role for climate change. “, said Dr. Mos.

“In our region, dozens of tropical species are moving south where oceans and estuaries are also warming faster than the global average.”

According to the records of the Atlas of Living Australia, the crossed-out javelin has not been collected in New South Wales for over 50 years.

The southernmost stronghold of the barred javelin is Queensland’s Moreton Bay off Brisbane, where the species supports economically important recreational and commercial fisheries.

The species is a popular sport fish and is said to be good to eat. The barred javelin reaches about 80 cm in length and is found in estuaries and offshore to about 75 meters in depth.

Dr Mos said the newcomer was not of particular concern for the environment at present. The relative rarity of the barred javelin in NSW and the generalist regime means it is unlikely to surpass local species.

In the Mediterranean, tropical fish that move towards subtropical or temperate zones threaten biodiversity, public health, and fishing. Two examples include herbivorous rabbits that nibble kelp forestsand venomous silver-cheeked toads fouling fishermen’s nets and stealing their catch.

In contrast, the barred javelin may be well received by recreational and commercial anglers in NSW.

“It is important that we understand where this species appears and in what numbers,” said Dr Mos.

“If more numbers head into New South Wales over the next few decades, the crossed javelin may become a more common catch. It may then be necessary to determine if specific size or catch limits are needed to ensure that more anglers have the opportunity to catch this fish.”

Because the barred javelin has rarely been caught in northern New South Wales, there are currently no specific catch or size limits for this species in New South Wales. A maximum daily limit of 20 catches applies to all fish in New South Wales that do not have a specific catch and size limit. A minimum length of 40cm and a limit of 10 bags apply in Queensland waters.

Fishermen, divers and General public can help scientists track the movement of fish and other marine organisms to new locations by reporting unusual sightings to RedMap Australia at www.redmap.org.au

Provided by Southern Cross University