Netting - February 2021

Results and update from the netting that took place on Saturday 20 February 2021

 

Firstly, thanks go to Bill Hailey for organising the netting and to the staff from Moore & Moore for doing the work.

Matt has uploaded a video of the event to Youtube and I've snagged a few stills to illustrate this page.

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Bringing in the net

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Bucket1.png

First bucket (of many).

Note the numbers of crucians! This is typical for most buckets.

That first bucket contained an estimated 60lb of fish, there were a further 19 buckets!

The first few buckets seemed to conatin an awful lot of small roach but the better fish started to appear as the fish were removed from the net, by the time bucket 8 was reached a few nice tench were starting to appear, unfortunately, as all members know, they are a little lean. However, that was the only downside, the rest of the fish were healthy and fat-as-butter.

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Lots of tench like this one

Just a few hybrids

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A beautifully scaled mirror

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No one who has fished the pond this year can doubt the way the roach are packing on weight

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One of the main things to note was that the bream are breeding well, there were fish of at least 3 year classes (excluding the stocked fish), and lots of them. There are thousands of small roach, the club will keep an eye on those to ensure we don't get over-run. Also, the crucians continue to grow well, there were plenty of them and they're pushing 10-12oz each now.

The netters estimated that they took some 1,400lb of fish and using their expertise on the percentage of fish missed, they think the pond contains 1,725lb of fish. This is at the top of the range for a healthy fishery of this size and they certainly don't recommend any further stocking at the moment.

However, it is possible the tench are thin because they are old, the committee will monitor the situation and manage the fish stocks to continue to maintain a well-stocked mixed fishery.

Report from Moore & Moore

 

TOTAL Estimated Weight Caught 625kg - 1380 lbs

(this figure is based on a count of 23 bins of fish caught, and presuming a weight of 60lbs / bin)

 

Fish stocks

Roach The most common species. Recruitment appears good and there was a significant size range. This would suggest that the growth rates are being maintained and the population is not suffering from too much stunting through excessive numbers

 

Rudd Very few were caught. These fell within a fairly narrow size range which would suggest they may well be from a single cohort. There was no indication of any recruitment and it should also be noted that they rarely compete well with a large established roach population.

 

Bream Significant numbers and biomass of Bream with a wide size range, were found. Some of the larger fish appeared to be ageing but as these die out it would be hoped that they would be replaced by the younger ones.

 

Chub Only a small number were caught. They appeared to be slightly out of condition, but this could be due to the less than preferred stillwater environment and the competition from other species.

 

Carp From memory, carp numbers may have been less than were caught during the previous netting in 2017. This reduction in catch may have been due to netting inefficiency, but it is also noted that some losses had been reported due to Otter predation. Carp are a species that tend to remain stationary in cover when threatened, a habit that may make them more vulnerable to this type of predation. The carp seen appeared in reasonable condition. A number of small carp were caught, suggesting that some limited but successful spawning has taken place.

 

Crucians A significant number of this species were caught. There was little variation in size and no small crucians were seen, suggesting that recruitment has not recently occurred. The number and size of crucians was notable in our experience.

 

F1 Hybrids A number of these fish were caught. All appeared to be in reasonable condition, and given the fact that they are still apparently relatively young fish, may provide an indication that lack of food is not the issue affecting some of the other species.

 

Tench A reasonable number of this species were caught. However some of the larger individuals appeared to be thin. This could be due to age, but may also reflect the high biomass and the less vigorous feeding habits of tench. There was no evidence of recruitment, consideration could be given to a limited stocking of this species, for the future.

 

Discussion

 

Following the electrofishing and seine netting it was estimated that 1380lbs of fish had been caught. If it is accepted that a catch rate of around 80% had been achieved this would give a biomass in the pond of approximately 1725 lbs. The catch rate for any one species may have been better or worse than the 80% figure. It is likely that species such as Roach, Bream, Perch and probably Crucians would have been caught at a greater level of efficiency, whilst Carp and probably Tench would have been less, possibly under 50%, especially with Carp.

 

Given that a rough recommended stocking density for waters of this size is around 1000lbs / acre, it can be seen that the stocking levels for the pond are somewhat higher than would be desirable. The provision of aeration and some supplementary feeding can enhance the carrying capacity but it should be considered that there is still a limit to the quantity of fish that the pond is capable of supporting. If stocks are near this limit, then condition of the fish and vulnerability to water quality issues and diseases becomes greater. Some thought may be needed to the issue of reducing this pressure by the removal of some of the stock. This is a management decision that is outside the scope of this report.

 

The question about supplementary feeding was briefly discussed. Any feeding will be increasing the biological load on the water. The uptake of the feed by the fish needs to be assessed (dragging the bed with a fine meshed landing net at feeding points). If there is uneaten food then feeding needs to be reduced. The most likely periods that feeding may need to be reduced or stopped is during either very cold or hot weather. Consideration may also need to be given to the angling pressure on the water. A lot of anglers, employing large amounts of groundbait on a regular basis can make additional feeding unnecessary. Good quality coarse fish feeds, would be best and if the feeding is conducted by a limited number of people (possibly as little as one or two) then basic 'husbandry' observations can be made. These can be a vital indicator if the fish are feeding normally, or not. In the latter case consideration can be given as to the necessity of continuing feeding, and the reasons why there has been a change in behaviour of the fish. It perhaps also needs to be considered that the more active feeding species are those that are most likely to benefit from any supplementary feeding.

 

Bank undercuts

There are certainly some sections of bank that have been undercut. These sections can provide valuable cover for some species such as carp and tench. Most of the undercuts appeared to be under the roots of the bank side trees, and did not appear to extend for long lengths. The most extensive undercuts were up to half a metre deep. It was difficult to assess the stability of the undercuts and it may be wise to monitor these sections during periods of lower summer water levels. The bank works recently carried out appeared to be well constructed in and no weak points were detected.

Conclusions

  The pond appears to be very well stocked, with an extensive variety of species.

  Growth rates appear to be reasonable but may not be maintained with the current stocking levels.

3   Consideration may need to be given to thinning the stocks, possibly some of the younger roach.

 

The level of such an operation will require discussion. The more fish that are removed the greater the resultant space that will be created for growth of the remaining stock. Light reductions will result in less obvious changes to the fish population but species such as roach can quickly replace those fish removed.