Australian River King
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Gigantic Cod
Narrandera Fisheries Center, Narrandera, Australia: Zeb Hogan swimming with a 1.2m Murray Cod in a pond at the Fisheries Center.
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That's a Big Fish
Lock 10, Wentworth, Australia: Zeb Hogan with a 1.15m Murray Cod - Australia's largest wholly freshwater fish. It can grow to a maximum length of 180 cm but cod in excess of 50 kg are rarely caught these days.
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Microchipping a Fish
Yarrawonga Weir, Yarrawonga, Australia: Zeb Hogan and Scientist Lee Baumgartner inserting a PIT tag into a Murray Cod. PIT tags are small glass tubes about 2cm long containing a microchip programmed with a unique code. When the fish swims pass an antenna in the river, information like time, date and PIT tag number are recorded onto a computer.
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Fish Transport
Lock 10, Wentworth, Australia: Zeb Hogan helping fishway managers transport a Murray Cod from the fish trap into a anesthetic tank. The Murray Cod is an aggressive and territorial species and they need to work fast to remove four cod out of the fish trap before they start attacking each other.
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Along the Electric Current
Murrumbigee River, Narrandera, Australia: Zeb Hogan and Research Scientist Ian Wooden electrofishing by a weir on the Murrumbigee River. Electrofishing relies on two electrodes delivering current into the water to stun fish. This method doesn't hurt the fish and larger fish are usually more susceptible to the electric current.
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Large Crayfish
Murrumbigee River, Narrandera, Australia: Zeb Hogan holding up a Murray Crayfish. The Murray Crayfish is the second largest freshwater crayfish in the world and a major food source of the Murray Cod. The legal size for bagging a crayfish is 9 cm.
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Open Wide
Lock 10, Wentworth, Australia: Close up of a Murray Cod's head. Murray cods have a broad, scooped head, and a large mouth lined with pads of very small needle-like teeth.
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Hey, Cod!
Narrandera Fisheries Center, Narrandera, Australia: Agro, the 90cm Murray Cod on display at the John Lake Visitors Center.
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Electrofishing Suited Up
Murrumbigee River, Narrandera, Australia: Zeb Hogan getting ready to go electrofishing. Electrofishing is a common scientific survey method used to sample fish populations to determine abundance, density and species composition.
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Examining the Fish
Narrandera Fisheries Center, Narrandera, Australia: Zeb Hogan and Hatchery Manager Matt McLennen examining their newly marked Murray Cod fingerlings by shining a UV light on them. They have just used a chemical marking technique that involves immersing the fish in a salt bath prior to immersion in a fluorescent dye. This process assists uptake of the dye and produce externally detectable marks. Calcein marking helps scientists distinguish between wild and hatchery-produced stock in order to evaluate the outcomes of fish stocking.
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Measuring the Cod
Edward River, Deliniquin, Australia: Zeb Hogan with angling guide David Carter. The pair has just caught their first Murray Cod of the trip and will take a measurement before releasing it. The minimum legal size of a keeper is 60cm. Most recreational anglers today are practicing catch and release in the Murray Darling Basin.
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A Stunned Fish
Murrumbigee River, Narrandera, Australia: A young trout cod stunned by the current of the electrofishing boat. Another native species of the Murray Darling Basin, a deep-bodied adult can grow to a maximum size of 16kg and 850mm.
