1kg every 10 days – WA Marlin Show Extraordinary Growth Rates!!

Did you know…

Two juvenile Black Marlin were kept during Gamex 2017, as part of a study looking at Black Marlin Biology in Australia, (as a contribution to a study by Sam Williams – a PhD student at the University of Queensland).

Left: Recfishwest CEO Dr Andrew Rowland with 1 of the Marlin captures. Right: Recfishwest Research team sampling Marlin number 2.

Sam aged these fish by extracting the fish’s ear bones called otoliths. Fish age is determined by counting the opaque zones, much like one would count rings on a tree to determine its age.

Left: Marlin ready for sampling – gut, gonad and ear bone samples were taken. Right: The Marlin’s otolith (ear bone) – the age is determined by counting rings, similar to the ageing of trees!

So How Old Were They?

Extraordinary Exmouth

When you think Exmouth, you think of Gamex. You may also think of it as your ultimate fishing destination; your opportunity to catch a big 1000lb Marlin or reel in big Sailfish or Dolphinfish.

Photo courtesy: Peak Sport Fishing Exmouth.

 So why and how is Exmouth such a coveted game fishing mecca?

 “Is there just more big fish in the waters off Exmouth?” In short – yes.

 “But surely with thousands of game fishers descending on Exmouth every year the fishing would decline?”

 Answer: It’s because the community value game fish so much, they’ve shown a desire to understand more about the fish they catch and preserve the iconic status of gamefish in WA for biological, social and economic reasons.

 In recent years there has been a number of ‘investments’ made to ensure the recreational fishing sector understand more about the fish we catch, and there’s no better example of this than Exmouth’s famous Gamex tournament!

 Recfishwest’s Research Team are currently up at the 2018 Gamex Tournament collecting samples of game fish that  come into the weigh station every night. It’s the 2nd consecutive year the team has headed up for the game fishing tournament to carry out this important work, with plenty of fish being submitted to allow for a solid set of fish data, potentially used for a variety of projects worldwide!

 

Tag a mate that…Tags fish?!

Fish tagging is another method used by game fishers to do their bit for ‘science.’ Tagging fish allows a percentage of the fish population to be monitored ‘in the wild’ with repeat catch records, giving insight into an individual fish’s movement and size over time.

Recfishwest CEO Dr Andrew Rowland with a tagged Sailfish in Broome.

Do you remember the 1000 pound Marlin caught off Exmouth earlier in 2018 by local skipper Eddy Lawler? You probably didn’t know Eddy has tagged over 1000 Marlin, many are recaptures of his previously tagged fish! That’s only one boat skipper providing over 1000 points of data for Marlin, making Eddy more of an advocate for fisheries research than most others worldwide! Read more about the 1000lb Marlin here.

So Why Aren’t All Fish Tagged and Released?

To understand more about the fish we catch at Statewide fishing tournaments, there are a number of different research techniques used to sample fish species that wouldn’t normally come into weigh stations at your local fishing club.

Gamex 2018 Yellowfin Tuna ready for sampling.

Fishing tournaments provide a great social and economic activity for regional towns in WA and is the fabric of a lot of communities, especially in fair weather months. So when hundreds of fishers descend on regional fishing clubs to go tournament fishing, a whole range of species are brought in to the weigh station, iced down and ready for the table. It’s at these times where the opportunity to collect samples from these species is at its’ greatest and goes a long way to helping researchers understand more about the fish we catch.

Researchers can quite quickly collect samples from species such as trevally, mackerel and cobia to help determine length, weight, age and diet from a few simple cuts – leaving the fish in high quality ready to for the fisher to take home and cook up!

Dietary data allows us to understand a species effects on the rest of their environment. It also allows the drawing of food webs and better grasp the entirety of the relationships between species – essentially ‘what eats what.’

What’s Next?

If you’re lucky enough to be fishing at the 2018 Shark Bay Fishing Fiesta in May, the Recfishwest Research Team will again be on-hand to sample the fish the competitors bring in – to help us understand more about the fish we catch and do our bit as a sector for conservation!

The 2018 Gamex samples that will be collected will be kept on ice and made accessible to research providers, such as Universities) who run specific projects looking at topics such as fish biology, population dynamics and age and growth rates.

 

How Can You Help?

Recfishwest will be taking their Research Team to as many statewide fishing tournaments as possible and we’re always looking for Supporting Partners who can help us achieve this. Your brand will be directly associated with research activities as described in the article above and is great way to enhance your corporate social responsibility! This will ensure high-quality fishing experiences are maintained and enjoyed, as an integral part of the WA lifestyle. Want to know more, email tim@recfishwest.org.au or check out our Partnerships and Sponsorship page here.

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