Sand Flathead bag limit scenarios

Setting a new Sand Flathead bag limit will only reduce catches on fishing trips where fishers would otherwise have caught above the bag limit (right of the dashed line). As of the latest statewide survey in 2017/18², 75% of fishing trips on which anglers caught and retained Sand Flathead, less than ten were retained. On half of these trips, only five or less Sand Flathead were retained. This is why reducing the bag limit by 50% does not reduce the total catch by 50%.

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Contact: IMAS.Science.of.Fishing@utas.edu.au for enrolment support

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^* This is a live model and may update at any time.

¹ Fraser, K., K. Hartmann, J. Haddy and N. Krueck (2022). Tasmanian Scalefish Fishery Assessment 2020/21. Hobart, 208pp.

² Lyle, J. M., K. E. Stark, G. P. Ewing and S. R. Tracey (2019). 2017-18 Survey of recreational fishing in Tasmania. Hobart, 123pp.

³ Froese, R., H. Winker, D, Gascuel, R. Sumaila and D. Pauly (2016). Minimizing the impact of fishing. Fish and Fisheries 17:785-802

⁴ Based on the results of the 17/18 Statewide recreational fishing survey (see 2).

⁵ Hoenig, J. M. (1983). Empirical use of longevity data to estimate mortality rates. Fish. Bull., 81, 898-903.

Sand Flathead bag limit scenarios

Set new flathead bag limit:

Bag limit reduction of resulting in

a reduction in total catch of

Based on the best available IMAS data:^1,2:

Fishing currently removes sand flathead from the stock at of the rate at which they are removed by natural causes of mortality like old age or predation.

Set a new Sand Flathead bag limit or commercial catch reduction with the sliders above to see the effect on the stock.

Under the bag limit of set above and a reduction in commercial catch of , fishing would remove sand flathead from the stock at of the rate at which they are removed by natural causes.

These parameters are from the best available field and survey data collected by and stock assessments conducted by IMAS scientists:

F (Fishing mortality rate) =

F (based on set bag limit) =

Z (Total Mortality, modelled range 0.96–1.79¹)

M (Natural mortality) =

Sand Flathead bag limit scenarios

Set new flathead bag limit:

Bag limit reduction of resulting in

a reduction in total catch of

Based on the best available IMAS data:1,2:

Fishing currently removes sand flathead from the stock at of the rate at which they are removed by natural causes of mortality like old age or predation.

Set a new Sand Flathead bag limit or commercial catch reduction with the sliders above to see the effect on the stock.

Under the bag limit of set above and a reduction in commercial catch of , fishing would remove sand flathead from the stock at of the rate at which they are removed by natural causes.

These parameters are from the best available field and survey data collected by and stock assessments conducted by IMAS scientists:

F (Fishing mortality rate) =

F (based on set bag limit) =

Z (Total Mortality, modelled range 0.96–1.791)

M (Natural mortality) =

Based on the best available IMAS data:^1,2:

Z (Total Mortality, modelled range 0.96–1.79¹)