The Conservation Report

A commercial fisher netting in shallow Tuggerah Lake, Australia, claims to have netted a great white shark (Carcharodon carcharias), which may have been around 21-feet in length. The commercial fisher’s boat is 18-feet in length, and he claimed the shark was larger than his boat. He took the shark in nets “he had cast off Canton Beach, at the northern end of the lake.” Despite the fisher’s account, some shark experts strongly doubt the encounter.

However, great white sharks have been recorded swimming in shallow saltwater lagoons and ponds. In 2004, a “1,700-pound female shark” was found swimming in a salt pond on Naushon Island, which is located near Woods Hole, Massachusetts. The 14-foot female great white shark “swam in circles in a shallow area filled with smaller fish”, but the shark was eventually coaxed into deeper water. Additionally, Tuggerah Lake has been visited by great white sharks in the past. From The Central Coast Express Advocate:

It is the second great white found in Tuggerah Lake since 2005. It comes on top of three other shark sightings in the lakes system in as many years. Experts fear the great white may be trapped in the lake unable to reach the sea because The Entrance channel is too shallow.

But the channel has been open to the ocean since last year’s June long weekend storms and after recent king tides others, including senior NSW Fisheries staff, believe large sharks could come and go as they pleased.

Furthermore, in spite of the title from the TIME magazine article: “Attack of the Freshwater Shark?,” which highlights the recent Tuggerah Lake encounter, Tuggerah Lake is brackish, since both freshwater and saltwater flow into the coastal lagoon. Furthermore, it has been reported that the fluctuations of salinity influences the species composition of the lake. Freshwater shark attacks are most likely to occur from bull sharks (Carcharhinus leucas), because their physiology allows them to enter freshwater for some periods of time. From TIME:

It was around 4 degrees Celsius on the lake at 5.30 am on Wednesday, making it the coldest morning of the year in these parts. Wrapped in several layers of clothing, the fisherman was startled by splashing noises coming from underneath his craft, then alarmed by a recurring thudding sound, as though something were striking it. Having rushed to one side of the boat, he peered down to see a gigantic fish trapped in a net….

“He said it was bigger than his boat,” reported local Chief Inspector Tim Winmill. “He’s got an 18-ft. boat and he said it would have been 21 ft. (6.5 m.).” Winmill said police had no reason to doubt the fisherman’s story: he was known to local authorities as a responsible member of the industry. As a result, police have issued a warning to anyone using Tuggerah and two smaller, connected lakes to take extreme care. Though the water at this time of year is numbingly cold, it’s school holidays in New South Wales until the end of next week and some children won’t necessarily be deterred from swimming or other activities.

How would the ocean-going monster have gotten into a freshwater lagoon? Tuggerah Lake is connected to the Pacific Ocean through a tidal channel called The Entrance. It is 12 km long and 4 km. wide, with an average depth of 6-7 m, roughly 20 feet. “It’s not a big lake,” said Chief Inspector Winmill, “but it’s a bloody big shark — if it’s true.”

Some images from the Massachusetts Division of Marine Fisheries of the 14-foot female great white shark found in a Cape Cod salt pond during 2004:

More images, videos, and press releases can be found at the Massachusetts Division of Marine Fisheries.

See more Shark Week on The Conservation Report

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