Diary anglers monitoring Lake Tyers
The Victorian angler diary program has been operating in Lake Tyers since 1999/00 and is currently funded by the Recreational Fishing Grants Program. Volunteer anglers have been contributing detailed information about their fishing trips including their time spent fishing, fishing location, species targeted and caught, fish lengths, number of rods and baits and hook type/sizes used.
Information collected by these volunteer anglers improves our understanding of fish stocks in Lake Tyers in particular black bream and dusky flathead by providing information on:
- Abundance of fish. Catch rates (fish caught per angler hour) of key species can be used as a measure of fish abundance. Catch rates can indicate whether there has been an increase or decrease in the population over time
- Health of the fishery. The length and ages of fish caught by anglers indicates the health of the fishery and can be used to forecast catch trends 2 to 3 years in advance
- Profile of the fishery. Angler diarists give an insight into the species targeted and caught in Lake Tyers as well as Information on which fish are kept and released.
- Local knowledge. Anglers provide their opinions on the status of key fish stocks and comment on trends in fish abundance over the past 5 years.
Volunteer anglers contribute to the angler diary program as either a 'research' angler or a 'general' angler. General anglers record information from their normal fishing trips. Research anglers target key species and if necessary alter their fishing techniques to catch the largest possible size range of the targeted species, including undersize fish.
Abundance of fish
Angler diarists recorded 120 trips for black bream and 55 trips for dusky flathead in Lake Tyers during 2010/11.
The catch rates (fish per angler hour) of black bream were lower than in the previous year (2009/10) but similar to the average over the past five years. Catch rates of dusky flathead were higher in 2010/11 than the previous year and similar to the 5 and 10 year average.
Health of the fishery
Data collected by angler diarists in Lake Tyers suggests that while the populations of black bream and dusky flathead are variable from year to year, they are resilient, in a healthy condition, and showing no evidence of a persistent decline in abundance.
Angler diarists measured 658 black bream in Lake Tyers during 2010/11. These bream:
- Ranged in length from 8 to 45 cm Total Length (TL)
- Were 1 to 21 years of age; most bream caught were 12 years old (34%) and from the 1998/99 successful spawning season
- Nearly a quarter of bream caught were below the legal size (23%). These bream are expected to recruit to the fishery over the next few years.
Anglers measured 479 dusky flathead in Lake Tyers during 2010/11. These flathead:
- Ranged in length from 15 to 79 cm TL
- Were 1 to 10 years of age; most dusky flathead were 2 years old (58%)
- Had higher catch rates this year than in 2009/10
- Were mostly below 50 cm TL (90%). There is concern over the decline in large dusky flathead (>50 cm TL) in recent years, suggesting the population should be closely monitored in the future.
Profile of the fishery
Over the past two years:
- 8 general anglers recorded catch information during 17 trips in Lake Tyers. Anglers caught over 100 fish
- Bream were targeted most often (82% of trips). During these trips 63 bream were caught and only 5% of these fish were kept
- Dusky flathead were also targeted (12% of trips). General anglers caught 8 dusky flathead and half of these fish were kept
- Dusky flathead were targeted during summer while bream were targeted throughout the year.
- Tailor were also targeted during spring, most were released.
Seven angler diarists who target black bream, dusky flathead or both species in Lake Tyers were asked how last years fishing compared with the previous 3–4 years. Most anglers thought:
- The average size of black bream had increased while the average size of dusky flathead had decreased over the past 5 years
- The abundance of undersize black bream had increased while there was a mixed response about the abundance of legal sized bream in the past year compared to the previous 3–4 years
- The abundance of undersize and legal sized dusky flathead had increased or were similar in the past year compared to the previous 3–4 years
- lack bream stocks are in good condition. There was a mixed response to the status of dusky flathead stocks in Lake Tyers; some anglers believe stocks are in good condition, others feel it is improving and some think the stocks are deteriorating.
Further information on the Angler Diary Program
If you would like to get involved or need a new diary contact the Fisheries Research Branch on (03) 5258 0111