As most members are aware, the ATDAC Committee have held meetings with the Environment Agency and a fisheries consultant (Dr. Andrew Worthington), to try to identify the causes of the deterioration of the fishing at Westgate Pond and Bishopton Mill over the last couple of years and to put in place an action plan to address the issues.
Despite regular stockings with a variety of species and sizes, the pattern at both ponds has been broadly similar. The first year after a stocking the fishing has improved, particularly for the recently-stocked fish. The next year has seen a decline, and the following year is even worse. And yet we are not seeing a significant level of fish mortality in terms of dead fish on the surface or the bottom.
Breeding success appears to be declining at both waters.
We know that both waters suffer from predation by cormorants and goosanders, and have tried various ways of minimising this. We have tried ropes at Westgate (and received complaints from some members and had some of the ropes stolen), installed a scarecrow and other bird-scaring devices at Bishopton, and we have a licence to shoot a small number of predators at both ponds.
We have installed otter-proof fencing at both ponds, with evidence that it is working at Bishopton where there is plenty of evidence of otter activity in the beck but none within the fence.
Based on those recent discussions, the ATDAC Committee have planned the following actions before undertaking any further restocking.
At both waters, we introduced a “catch returns” form to try to capture actual data (rather than just hearsay) regarding how often the waters are fished and the size and quantity of each species caught. We appear to have had a good response from most of our members, and we are building a useful database from this information.
Please continue to fill in the catch return form whenever you fish the waters, a “nothing caught” return is as useful as information on the number and size of all fish caught.
| ISSUE | RECOMMENDED ACTION | CURRENT STATUS |
|---|---|---|
| Large leaf fall quantity each year, resulting in nutrients building up in the silt and water, leaves not rotting and low dissolved oxygen levels. | Reduce the number of trees around the pond. | Nearly all trees on the bank of the pond and approximately 50% of the trees on the area outside the otter fence have been felled. |
| Lack of water circulation around the pond. |
Reduce the number of trees around the pond to allow better circulation of surface water by wind action. Dig a connecting trench between the “car park bay” and the “Darlington” bay? − not recommended by Dr. Worthington. | Nearly all trees on the bank of the pond and approximately 50% if the trees on the area outside the otter fence have been felled. Wave action is now much better.
We have decided not to proceed with digging any trench at this stage. |
| Organic matter and high nutrient levels in the sediment. |
Treat with Microchalk at a rate of 1 tonne per acre in late October, with a follow-up treatment in January/February if the previous dose has dissolved. | 2.5 tonnes of Microchalk were put into the pond on 5 November 2017. |
| Excessive first-year weed growth after treatment with Microchalk. | Apply Swarm when water temperature exceeds 10C, to reduce the nutrient level in the water column. Apply Excalibar if filamentous algae develops. |
We will review this in the spring/summer of 2018. |
| Ongoing growth of rooted weeds. | Potential to transfer carp from Bishopton Mill for a few years, subject to EA permission. | No decision made at this stage. ATDAC committee will review the policy of “self-sustaining silver fish fishery” on an ongoing basis. |
| Low dissolved oxygen content in most of the pond. | Instal water aeration equipment (Linn AquaWheel 0.55Kw plus genset). Regularly monitor dissolved oxygen level using suitable test equipment, and deploy aeration equipment as necessary. |
Because of the likelihood of theft of such equipment, we are experimenting with a smaller, portable pump which can be removed from the fishery each day. We have purchased a meter to measure the dissolved oxygen level and will be periodically monitoring the situation. |
| Lack of ability to “flush water through” the pond after Microchalk treatments, to further reduce nutrient levels. | Nothing recommended but could we re-instate the water supply?. | On hold, until we see the impact of other actions. |
| ISSUE | RECOMMENDED ACTION | CURRENT STATUS |
|---|---|---|
| Shallow depth of the water, and a rapid accumulation of silt in some areas of the lake. | None, except for sediment consolidation by Microchalk treatment. | - |
| Organic matter and high nutrient levels in the sediment. | Treat with Microchalk at a rate of 1 tonne per acre in late October, with a follow-up treatment in January/February if the previous dose has dissolved. | 3.5 tonnes of Microchalk were put into the pond on 8 November 2017. |
| Excessive first-year weed growth after treatment with Microchalk. | Apply Swarm when water temperature exceeds 10C, to reduce the nutrient level in the water column. Apply Excalibar if filamentous algae develops. |
We will review this in the spring/summer of 2018 and 2019. However, an increased amount of suitable weed is necessary to ensure good spawning success for the silver fish. |
| Deterioration of the quality and quantity of roach and rudd.> | Remove aggressive bottom-feeding fish such as carp and barbell, as these are likely to have been a significant factor in the reduced spawning success of roach, rudd and tench because of a lack of suitable weed growth. | No decision made at this stage. ATDAC committee will review the policy of “self-sustaining silver fish fishery” on an ongoing basis. |
| Extremely high phosphorous level in the lake water. The lake was originally filled from Stillington Beck, and has subsequently been “flushed through” several times from there, it may be worth investigating the water quality in the beck. | Report to Environment Agency, and request that they undertake water quality analysis.
Alternatively, contract a commercial company to do a water quality analysis for the beck. |
This has been reported to the Environment Agency, which has decided not to take any further action at this stage. The ATDAC committee will review whether to undertake further water quality analysis. |
| High phosphorous level in the water in the ditch. | Report to Environment Agency, because the ditch could be considered the source of diffuse pollution and is probably classed as in-line waterway as it ultimately connects to the River Tees. | This has been reported to the Environment Agency, which has decided not to take any further action at this stage. |
| Inability to “flush water through” the pond after Microchalk treatments. | Only “flush through” from the beck or ditch, when the nutrient level (particularly phosphorous) of the flush through water is lower than in the lake. | On hold, until we see the impact of other actions. |