No need to travel 400km for a 5kg flathead is no evidence of problems with yanks in terms of sustainability. As they are now virtually a recreational species in Port Phillip and Western Port bays, what’s in question is whether anglers are content to view them as a larger version of sand flathead, rarely exceeding 1kg in size. Or, while continuing to take them under lower catch limits, are anglers prepared
VICTORIA
Ross Winstanley
As commercial net fishing winds up in Port Phillip, the prospects of a flathead of 5kg or more are rising. Yank or southern bluespotted flathead can grow to 90cm and 8kg, and it’s not long ago that 5kg and 6kg yanks were weighed in at a local fishing tournament. Encouragingly, a national record for a speared 4.2kg yank from the bay was confirmed just months ago. Flathead of such calibre are the ‘hook’ for much of the regionally important tourism industry in East Gippsland where dusky flathead lure Melbourne anglers to plan their holidays around waters 450km away, as far as Mallacoota, or even further up the East Coast. On
Fig.1 Lengths of 732 yanks caught under the Victorian Fisheries Authority’s Angler Diary program. 60+cm yanks. Fig.1 shows the lengths of 732 yanks caught under the Victorian Fisheries Authority’s Angler Diary program. Most were between 30-50cm long, which a Tasmanian study suggests
This promises to add an exciting dimension to fishing in the Bay. Even at sizes of 40-60cm, yanks have long been a welcome bonus to any angler’s catch and a regular target for spearfishers.
A Ta s m a n i a n University study shows that, initially, yanks grow rapidly, with both sexes reaching 30-40cm in three years. At that stage male growth begins to plateau with few exceeding 50cm and 1kg, while females can reach 90cm and 8kg. They begin to mature when around 35cm, at ages 2-3 years. Almost all yanks are sexually mature at 40cm and four years of age. The management implications of the rapid early growth is that both sexes can be taken before they have had a chance to spawn. A 40cm minimum size would be needed to allow most yanks to reproduce at least once before being taken. Judging from the lengths shown in the graph, most yanks caught in the bay are less than five years old, although both sexes can live beyond 16 years. Large older mature females are extremely scarce. In Victorian bays there
This 5.5kg yank came from Tasmania’s west coast. Photo courtesy of Geoff Wilson.
This record speared yank flathead measured 81cm, weighed 4.2kg and was aged at 14 years. Photo courtesy of Jordan Hill. Tasmania’s north coast, what started as a ‘niche’ fishery for large flathead, mainly among local lure anglers, has grown to the point of being a popular, well regulated recreational fishery. Now there’s a real prospect of flathead fishing that goes well beyond ‘frogs’ and into ‘crocs’ territory, right here in the bay. HOW COME? Decades of fishing pressure in the bay have thinned out the ranks of 102
JULY 2021
to ‘invest’ in building the stock of 2-8kg fish? LET’S BUILD THIS FISHERY The yank stock in the bay has sustained the combined pressure of commercial and recreational fishing for more than a century, but at the cost of the larger fish. So, to accelerate the rate of recovery, there are some lessons to be learned from
are 2-7 years old. Keeping in mind yanks’ potential to reach 80cm, the lack of fish above 60cm long and the steep slope of the right hand side of the graph reflect the high death or mortality rate due, in part, to the impact of fishing. The 20-year wind-down and, now, the complete removal of a commercial net fishery taking 15-20 tonnes of yanks annually, will help to build this stock overall, and creates the opportunity to rebuild the numbers of 5-8kg fish.
STOCK STATUS AND BIOLOGY Yank flathead occur from southern WA to eastern Bass Strait, including northern Tasmania. In Victoria, they are mainly taken by angling in Port Phillip and Western Port bays, and Corner Inlet, where they are mainly caught on light reef, seagrass and sandy bottom. Studies in Tasmania and WA indicate that their main spawning period is spring/ summer in marine bays and coastal waters.
There’s a real prospect of yank flathead growing beyond 40-60cm frogs, on to 7090cm crocs in Port Phillip Bay.
elsewhere. For example, despite the removal of commercial fishing from Mallacoota Inlet in 2004, the advent of year-round targeting by TV show-inspired soft plastics anglers seems to have slowed the build-up of large dusky flathead there. While duskies have the potential to grow to 15kg, fewer than 1% of those caught there by anglers exceed the upper slot size, 55cm. In Lake Tyers fortunately, the recent increase in the numbers of duskies of above 55cm suggests that the combination of the slot size and 5/day limit are succeeding in allowing more fish to survive longer to reach larger sizes. These Mallacoota and Lake Tyers observations point to the need for effective management of fishing pressure on fish within the keepable size range, to enable enough numbers to survive to reach
