Combatting Fishery Predation

Angling Trust Fishery Management Advisor update – Jake Davoile and Richard Bamforth

We are pleased that the renewal of our contract allows us to continue our work as Fishery Management Advisors with the Angling Trust for another two years, with our roles directly funded by rod licence money from the Environment Agency.

We are available to any fishery in England to offer site visits and bespoke advice on:

  • Improving refuge for fish from predation
  • Modern, effective non-lethal scaring methods
  • Individual & Area based Cormorant control licence applications
  • Coordination of action through ‘Area based’ licences
  • Monitoring bird numbers and evidencing of the impacts of predation
  • Protecting fisheries against otters through fencing
  • The Legal and humane trapping and removal of otters from fenced fisheries

Piscivorous birds

There are now 16 area-based licences to combat predation by piscivorous birds, ranging in size from 10 to 40 individual sites and include stretches of rivers, stillwaters, and fish farms, bringing fishery managers together for the greater good. Some have now expanded with almost complete coverage across a catchment. The benefits are clear, with fisheries complementing coordinated lethal action with the most suitable non-lethal techniques to reduce rates of predation that in many cases were at an unsustainable level. By collating knowledge on cormorant movements and behaviour, we get a clear understanding of the feeding patterns of birds, thus gaining the ability to react to any changes in their routines and adapt the shooting strategy and non-lethal techniques accordingly.

This shared knowledge is highlighting population distribution shifts as well, with breeding populations of Goosanders noted in a number of new catchments. A rare sighting only a few years ago but what might the implications be for fish if numbers escalate?

Whilst the area-licences have many positives, cormorant predation is unfortunately still a huge issue, as each winter we experience a migration of tens of thousands of the European sub-species carbo sinensis birds from the continent coming across to overwinter and feed. Coupled with the expanding inland breeding population of cormorants, numbers reported last winter were simply overwhelming for a large number of fisheries. Whilst we aim to work on a catchment scale in England to address our problems, we are working closely with our partner organisations in the European Anglers Alliance  as we know that birds do not recognise borders! Whilst our fish live within a closed system, the vast majority of our over-wintering cormorants do not, and return to mainland Northern-Europe during the spring and summer months to breed. The predator-prey relationship certainly has interesting dynamics when a predator’s migration to breed is thrown into the mix.

Moving back to our inland breeding population of cormorants, in the past month we have discovered two new cormorant colonies, both containing over 120 breeding pairs, further indicating that the true scale of impact is yet to be fully understood. Not only damage to fish populations, as there are numerous cases where heron colonies have been displaced by the destructive properties of cormorant guano and a cormorant’s ability to nest in the whippier branches directly above that of a heron. Further knock on effects can include loss of habitat to other ground nesting waterfowl and associated issues with water quality.

This SSSI was noted for its nationally significant heronry. The cormorants have moved in, displaced the herons, and are gradually destroying the trees and soil chemistry of the island.

To finish on the bird front, time and time again we encounter a polarisation in opinion when it comes to reducing the impacts of cormorant predation. On one hand you have the ‘shoot them all’ camp and on the other you have the ‘get the habitat right and the fish will look after themselves’. We have found in truth that it’s a sliding scale and reducing predation requires a multi-faceted approach. Whilst improving habitat must be seen as one of the primary long term solutions to aid fish survival, shooting to kill will unquestionably enhance the scaring impact on the other birds in a group, as well as improving the efficacy of a whole host of non-lethal techniques which can subsequently be applied.

The margin of this floating bed of Phragmites is incredible habitat for invertebrates, birds, mammals, and amphibians, as well as perfect sanctuary for silver fish. However, without daily scaring it was a noted feeding ground for up to 45 cormorants.

Mannequins – A proven tool to complement lethal control. These need to be proactively managed and the danger reinforced with regular shooting to kill/scare, otherwise habituation will quickly occur.

Otters

Love them, or loathe them, otters are here to stay and enjoy strong legal protection. Viewed by many wildlife organisations as the major environmental success story of the past few decades, otters have returned from the brink of extinction, whilst other native aquatic species, such as Atlantic salmon, white clawed crayfish and water voles have continued to decline dramatically.  To some anglers they are the scourge of the banks, to others they are an apex predator, with a legitimate place in the food chain, indicating the favourable conditions of the environment within which they live.  Every angler will no doubt have their own opinion depending on personal experience and this emotive debate is likely to continue for some time to come.

In recent years a great deal of time and effort has been given by those passionate about their sport in trying to find fencing solutions to the predation dilemma faced on some fisheries to safeguard their prized and highly valuable fish stock. There are now even some cases of non-fishery sites being fenced to protect vulnerable species from predation, including that by otters.  This is certainly not ideal and merely fuels the debate for those water bodies that cannot be fenced.

The Angling Trust is working closely with a variety of key stakeholders including Embryo, Otterstop, the Carp Society, the Predation Action Group, UK Wild Otter Trust as well as the Environment Agency to better protect fisheries.

The FMA’s are available to give free advice to fisheries  across the country including fencing options, and potential funding opportunities. They are both trained and qualified to operate under Natural England’s WML CL-36 Class Licence to lawfully and humanely trap otters from within fenced fisheries. Whilst only operational for a few months, there have already been a few success stories.

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