Last week was cold. We left Canberra on a breezy icy Monday morning and headed for Caddigat Lakes. After scraping the frost from the windscreen, we watched the temperature gauge dip as we headed south and saw our first roadside snow at the Berridale turn off on the Snowy Mountains Highway. It was cold, and it stayed that way, with strong southerly gale force gusts.
We spent the day fishing the small dams and avoiding the wind. The fish cooperated and John caught his first from Kidney Dam on an orange Woolly Bugger fished deep off the wall. An 8 lb female rainbow in full spawning colour.
Moving on from that, as many might know I worked at NSW Fisheries for a good part of the period from 1991 to 2004 but never knew another eminent NSW Fisheries employee, Richard Tilzey. I might have met him but even if not, I’m certainly well aware of his passion for trout fishing, trout science, and his knowledge of trout fisheries. Richard recently wrote in the NSW Fresh Water Fisher about the Snowy Lakes grout fishery. I agree with a lot of Richard’s comments and suggestions, but specifically not an increase in possession limit (which I would reduce, along with bag limits). I would also like to see some stocking of advanced size fish before we spend money on science trying to prove what we all know, that the mortality rate of stocked fry is immense. I’m afraid I can’t be quite as dismissive of the anecdotal evidence, nor do I think the subtle digs at the bureaucracy or the Minister are helpful (walk a mile in their shoes). I’ve included the article in full below.
Tight Tippets all – not too late for a winter charter on Eucumbene or Tantangara www.nakedtrout.com.au
Cheer, Steve
Thoughts on the Snowy Lake Fisheries. Dr Richard Tilzey.
As a fisheres scientist who participated in the recent series of trout meetings, I left feeling frustrated at the ongoing lack of commitment by the DPI to monitoring these valuable lake fisheries. Hence, I’m sharing a few of my brief thoughts on how to improve the management of these fisheries. I note that some have dismissed my earlier research on Lake Eucumbene as “no longer relevant” but am sure that most of my scientific colleagues would dispute this claim. We certainly don’t want to reinvent the wheel.
These meetings were in part prompted by an apparent downturn in the rainbow populations in Jindabyne and Eucumbene. However, in the absence of any monitoring of the angling catch, the claims of reduced abundance are anecdotal only. The only hard evidence for a downturn is from the Jindabyne fishery where a reduction in the annual number of spawning rainbows entering the Gaden Hatchery’s upstream trap on the Thredbo River has been documented. A high priority should be given to establishing an ongoing catch data collection system for these two major lakes.
Such catch data systems do not need to be all encompassing, nor are they expensive to maintain once established. When I was working on Eucumbene (1967-80) I supplied the major accommodation/boat hire complexes on the lake with scales, measuring-boards, and record books and encouraged anglers and staff/proprietors to use them. This system provided increasingly valuable data as anglers grew accustomed to recording details. Regular feedback of analyses (wallcharts, graphs, etc) is essential to maintain angler interest. Unfortunately, when I left NSW Fisheries this system was not serviced and subsequently faded away. It’s interesting to note from a rainbow perspective that length frequency analyses showed annual rainbow recruitment into the rod fishery (i.e. 25 cm length) over 1967-80 to fluctuate markedly, whereas brown recruitment remained comparatively constant.
It should further be noted that such catch data collection sites were usually in close proximity to freezers where visiting anglers stored their catch. Hence, the current possession limit of 10 fish may mitigate against the volume of data collected. The possession limit should be increased, particularly as the 2001 Economic Survey by Dominion Consulting Pty Ltd showed the majority of fishing trips by inter-state anglers to be a week or more in duration. The limit has obvious socio-economic implications for tourism. In any event, whatever catch data collection system is adopted, it should be introduced as soon as possible.
From the early 1980s onwards both fisheries have received large annual stockings of rainbow fry/fingerlings. Despite over three decades of stocking, little is known about the survival of stocked fish and the effectiveness of this practice. I reviewed the effectiveness of Eucumbene’s rainbow stocking in 2000 (see attached, pages 82-86) and regrettably little has changed since then. There has been no comprehensive study to determine what proportion of stocked fish eventually reach the rod fishery or survive to contribute to spawning biomass. A key question is: if the rainbow decline is real, is it attributable to reduced natural recruitment, lower survival of stocked fish, or both?
Another factor could well be increased fishing mortality as rainbows are much more readily caught than browns. Back in the 1970s annual fishing mortalities of up to 30% were recorded for marked fish in Eucumbene and overall fishing effort has certainly increased since then. When anglers were first allowed to catch spawning browns in Eucumbene, the end of the closed season was also extended to 1 November to protect spawning rainbows, many of which spawned in October. A high priority should be given to bringing back the 1 November opening for all Jindabyne and Eucumbene spawning streams. Surely this can be implemented by 2015?
All stocked fish now come from the Gaden Hatchery. In the past many of these rainbows have been finclipped prior to release to distinguish them from wild fish. However, finclipping has proven to be an unreliable tool because of unquantified fin regeneration and anglers’ failure to recognise (look for) missing fins. This practice is time consuming and archaic and should cease. The recent shift to using implanted wire tags is a positive step towards supplying the information needed for management, providing appropriate monitoring is in place.
If I was managing the Jindabyne and Eucumbene fisheries my research/management priorities would be as follows.
Both fisheries
* Move the opening date for spawning streams back to November 1.
* Establish and service voluntary catch data collection systems. Data such as species composition, size composition and catch per unit of effort are essential to detecting any changes in the rod fishery.
* All, or a large fixed percentage of, hatchery rainbows to be marked with wire tag implants prior to release. The timing/duration of this procedure and the numbers marked should be determined by monitoring/research plans for the immediate future, such as creel censuses or scientific netting sampling. Major catch data collection sites should be supplied with tag detection devices within 2 years of release. The first question to be addressed should be what proportion of the population/catch comes from stocked fish.
* Collect essential limnological data on water chemistry/quality, temperature/dissolved oxygen profiles, plankton ,etc. Once the seasonal patterns have been determined, annual sampling should suffice (I would hope that nutrient levels in Jindabyne are already being monitored).
* It would certainly be useful to obtain current fishing mortality estimates for rainbows. This will require mark and release studies using trapped spawning fish marked with external tags and monitoring via appropriate publicity and a tag-return reward system.
Jindabyne
* The hatchery trap is an excellent sampling tool and can be used to assess both brown and rainbow populations. The trap should be serviced daily throughout the spawning seasons and all fish sexed, weighed and measured, with ageing samples taken where appropriate for browns. All rainbows to be checked for wire tags as this will provide information on population composition (stocked versus wild), age, growth, etc. Daily river heights and trap inundation days to be recorded.
* The trap information would be enhanced by routine gillnetting samples from the lake in March/April to determine percentage maturation for both species and, more importantly, provide lentic population composition data, particularly because of the additional presence of brook trout and Atlantic salmon. Angling catch compositions are obviously biased because of different catchabilities between species. Biological data (see below) should be collected from all netted fish.
* Once the contribution of current fingerling stocking practices has been estimated, a targeted study should complete a cost-benefit analysis of releasing fewer yearling fish via appropriate similarly-marked releases and routine monitoring. Results can also be applied to Eucumbene.
Eucumbene
* The current spot sampling of the brown spawning run achieves little as it is prone to considerable bias. The size of fish diminishes throughout the run and standardising annual sampling times is problematic because of varying stream flow, a major upstream migration stimulus. This should cease.
* Spot sampling of the rainbow spawning run could provide useful age/growth and population composition information providing hatchery releases are marked with wire tags. Sampling should commence in the
third winter after release.
* An ongoing regime of annual gillnet sampling should be established, taking a minimum of 200 fish of each species, All fish to be sampled for sex, weight, length, age, maturation and stomach contents. Sampling sites and times and mesh sizes should be standardised as far as is practicable, noting fluctuating lake levels.
To achieve the above aims it is obvious that more resources are needed. It appears that only a minor proportion of the current “Effectiveness of freshwater stockings & recreational freshwater fishing assessments” program’s budget ($229 K) is directed towards trout fisheries. Indeed, the bulk of recent NSW freshwater fisheries research has been on native fish. Over the past two decades trout fisheries have been neglected, apart from annual stockings.
I simply don’t concur with the DPI fisheries manager’s plea of “limited resources”. He should be pushing for additional funding. The 2001 economic survey clearly showed that the Snowy trout fisheries are generating a revenue of many millions of dollars (then 50-70 M) for local businesses, much of which comes from interstate anglers. The Monaro Acclimatisation Society, local business stakeholders, the NSW Council of Freshwater Anglers, the Advisory Council on Recreational Fishing and other interested groups should all be lobbying for more research funding and stressing the economic importance of these fisheries to the NSW tourism industry.
A strong case could be made for introducing a specific, additional ‘Snowy Lakes’ licence encompassing Eucumbene and Jindabyne (and inflows) incurring a modest fee ($10 week, $20 season?), with all such revenue being spent on these fisheries. However, the Minister of the day would probably blanch at such a proposal.
