In this case it should be the sharks that should be alarmed, not us.
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There are several species of sharks that were once common along our coast. Most of them will not harm humans unless harassed. These ancient creatures, highly evolved for life in the sea, are all slow to reproduce and their numbers have been decimated by fishers, both commercial and recreational. The Sanctuary Zones in the Batemans Marine Park were the only places where some of them were safe, until line fishing from shore was allowed in most of the sanctuaries.
Grey Nurse sharks were once mistakenly thought dangerous and were fished by line and speargun until only a few were left. They are the slowest reproducers of any shark species, with females taking up to eight years to mature and producing only two babies every two years. Now they are listed as critically endangered and are protected but many still die in beach nets or suffer from being accidentally hooked. Although hooked sharks are mostly released, their hooking causes festering sores, stomachs laced with hooks or lines and lures trailing from an embedded hook.
Some sites where the Grey Nurse Sharks aggregate in summer, such as Montague Island, have seasonal closures to reduce the likelihood of them being caught. But as the water warms with climate change the sharks are staying beyond their protection period.
Wobbegongs are beautifully camouflaged medium-sized sharks that are often seen by divers and snorkelers. These nocturnal sharks lay in wait under overhangs and pounce with lightning speed on their prey - crabs, fish or octopus. Wobbegongs only reproduce every three years and while they can have an average of 20 live young, most of the babies do not survive.
Unfortunately, the Wobbegong is also under threat, many of them ending up in fish shops, marketed as 'flake'. Total catches of Wobbegong in NSW waters halved from 1991 to 2001, indicating that their numbers are plummeting. Recreational fishers are supposed to release any they catch but they are often injured in the process. They too need protection.
Studies of Fiddler Rays that were caught while pregnant showed that the females and offspring suffered health issues even after release. Pups from mothers that had been caught and released from trawl nets were 12 per cent shorter and 27 per cent lighter than those from un-trawled mothers. Similar effects are likely in all live bearing sharks.
Some of our most primitive sharks are the Port Jackson (PJs) and Crested Horn/ Port Jackson sharks. These docile fish hunt at night and have teeth adapted to crush their shellfish and urchin diet. They are often found in-shore during the winter-spring mating season, when they are most likely to be caught by rock fishers. Both species are slow to mature and lay a few eggs, each in its own spiral leathery case. PJ embryos in the eggs take up to 11 months to develop and 89 per cent die before hatching.
While not usually targeted by fishers, PJs are not legally protected and can be caught for "sport". However, most fishers comment that they are not worth eating.
The Nature Coast Marine Group has an extensive program of activities where members can have fun learning about our marine environment. To find out more about the Group and to see other stories in this series, visit the website www.ncmg.org.au or search for Nature Coast Marine Group on Facebook and follow us there.
By Jenny Edwards
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