Holtwood Pools have been in desperate need of attention for some time now, with the top and middle pools not fishing well for the last couple of seasons. There were many opinions as to what the underlying reasons were. However, the main cause was believed to be predation over a period of time from the visiting cormorants. This had become worse as less and less members were turning up to fish and the cormorants became less frequently disturbed.
We were also concerned the recommended dye process that had been employed for a number of years to try and combat the weed that was making the ponds almost unfishable at times, was having an adverse effect on the growth rates of the fish, but in particular the crucian. As many members know, the waters had suffered from parrot feather weed in the past which was made worse, and more prolific, by being physically cut.
One of our members and our match secretary managed to catch a good selection of crucian of which we were able to take scale samples from and send away to the EA fish analysis department where they were able to carry out some age testing on the scale samples. The results of this showed that the group of test scales we sent were from fish of varying ages with the older ones showing good growth rates in the early years but then slowing down rapidly which coincided with the use of the dye to combat the weed. In essence, the crucian appeared to have become stunted.
We have learned through reading scientific papers on crucian breeding that the dye, although perfectly safe to water life, does prohibit the existence of zoo plankton within the water which is the start of the food chain that creates the natural food that the shy feeding crucian relies on to thrive and grow. So, these smaller fish not growing beyond cormorant-proof size has left them vulnerable and their numbers, along with other fish like the roach and small tench that had bred in the ponds, have decline in numbers through the predation that we feared had taken place.
Whilst we have had an English Nature licence to cull cormorants over the years it is simply not possible to be there all the time and, whilst we have a neighbour that alerts us as and when they see them, again getting there at the right time to have any effect is difficult. We have been successful over the years in controlling the numbers but with the decline of anglers attending they seem to have been dropping in at all different times of the day more frequently through the winter time.
At the end of the summer and into autumn, it was decided that we needed to take action and see exactly what was going on in those two top ponds. We started in September by digging out a future stock pond which we can protect with a net and rear on our own fish to replace the inevitable losses that occur on all fisheries. This pond will be worth its weight in gold in years to come.
We then moved on to the middle pond which had the most severe weed and the lowest catch results. We started off by pumping out all of the water. This was no mean feat as we had continual rain that was draining back into the pond but eventually, we got there. As this draining went on we netted any sizeable fish that were present. Sadly, as we feared this was very few.
We then hired a machine and along with voluntary help and a hired machine operator we managed to dig out much of the dead weed and years of build-up of silt. Some of this silt we managed to dispose of around the fishery. As we didn’t want to damage the rest of the fishery we then decided with some modifications to the island and a disused corner we could dispose of the remaining unwanted silt within the pond itself.
Once all of the ground work had been done we ended up with some nice clean clay areas and it was ready for refilling. This did not take long as we had prolonged rain so it soon filled up.
After taking advice from fish farmers and discussing the results of our fish ageing testing it was decided that the best solution for this middle pond would be to stock fresh mirror carp along with some other species in the future. These new fish will stir the bottom up with their aggressive feeding which will helping reduce the ability of the uncontrollable weed to take hold, significantly reducing its growth. They will also give anglers something to fish for, they are fantastic looking fish and will lure anglers to the complex all year round, rather than the top and bottom ponds that remain purely crucian and tench waters that members visit predominantly in the warmer months. As these middle pond fish grow we will use them to stock other waters, rather than spending large amounts of money on sizeable fish in the future. They will be replaced by fish from the on-site stock pond. Having more members fishing the ponds throughout the year will help deter the cormorants from dropping in and feeding on the empty venue unnoticed.
This middle pond has now had tome to bed in and the fish have also settled into their new home very well. A few anglers have already fished this middle pond and have been catching its new residents, all of which have been reported to be in beautiful condition and providing fantastic sport.
The plan was to move straight on to the top pond and carry out the same clearance process so that we could get this ready for another go at the crucian and Tench project. As mentioned before this is something we do not want to give up on as we feel it gives a great alternative fishing experience that many members enjoy. We are confident with the new information that we have and with the correct feeding programme that we should be able to make this pond into a really fantastic crucian and tench fishery for the future.
Sadly, the weather had other ideas and with prolonged rain we simply could not get the water level down to drain the pond so that the machine could get in and clear it out. This work is due to be re-booked. As soon as a machine and driver are available, and a window of suitable weather arrives.
After visiting the ponds today, I have to say, the middle pond is looking really good so if you fancy some winter fishing, into early spring it’s well worth a visit to try the new middle pond and of course the bottom pond that has been consistently fishing well for tench to 6lb plus.
We will keep you posted as this project and others progress.
Russell Shaw & Stacy Wellington
CAC Chairman & Fishery Manager