An Environment Agency (EA) survey of Victoria Park’s East Lake has revealed an alarming lack of small fish, thought to be the result of predation by Cormorants.
East Lake was extended as part of the Lottery-funded improvements to Victoria Park in 2011-12. Around 8000 native fish, including Bream, Tench, Perch, Chub, Roach and Gudgeon, were stocked in 2012 and 2013, as part of the lake’s biodiversity and to provide angling faclities for local people. This has been promoted through a series of Fishing Taster Days, which have attracted many beginner anglers, especially children. Low catches in recent sessions, and an ever-increasing number of Cormorants roosting in the park, prompted park staff to contact the Environment Agency to carry out a survey to see what fish remained in the lake.
On 17 February, the Agency, assisted by Victoria Park staff and volunteers, conducted a series of seine netting operations. These covered approximately 75% of the lake and all suitable habitat for fish. Stop nets were used to divide the lake into manageable sections to increase the efficiency of the netting operation. The three small areas that were not netted were very shallow, crystal clear sections of the lake with practically no cover, where fish would not be expected to be found in the cold weather.
The netting revealed a few impressive large fish, but overall fish numbers were low. The total catch was four Carp between 3kg and 6kg, four Bream of 2.6kg to 4.1kg, and nine small Perch. Not one Roach, of which 5000 were stocked, was found, and the only small fish were Perch, which are very spiny and not favoured prey of fish-eating birds. The conclusion of the EA’s George Horne, who supervised the netting, was clear: “My immediate suggestion would be that the lake has suffered from heavy Cormorant predation. This is evident with the majority of fish sampled on the day being generally ‘cormorant proof'”.
Cormorants have increased greatly in numbers in Britain in recent years. Formerly a strictly coastal bird in this country, they have started nesting inland, and a sizeable colony can be found at nearby Walthamstow Reservoirs. This rapid increase may be linked to the number of commercial fisheries that are stocked with artifically-high densities of fish for anglers, but which incidentally provide very easy meals for Cormorants.
The lack of cover in East Lake leaves fish there extremely vulnerable to visiting Cormorants. To address this problem, habitat enhancements to the lake are required. George Horne says “my recommendation would be to install a number of floating reed rafts with fish cages beneath in the open, deep water section of the lake between the two islands. This will offer refuge for smaller fish species and the root networks below the floating islands will also offer good spawning habitat for fish species such as Roach, Rudd and Bream. I would recommend that this is done prior to restocking as unfortunately you are likely to see further depletions in fish stocks if sufficient cover is not present when they are introduced”. Victoria Park staff will be looking to take these recommendations forward over the coming months.
