Cull or cure: a bird’s-eye view for fishermen
The solution to the cormorant ‘problem’ is in sight, reports Jack Watkins
The cormorant is not an attractive bird. Notwithstanding the regal pose it assumes when holding out saturated wings to dry, or the fine, glossy sheen of its coat, only its close relation, the shag, surpasses its prehistoric ugliness among the breeding birds of Britain. But anglers and fisheries can live with the fact that the cormorant is no oil painting. Their problem is that it is supremely adept at catching fish.
In China, fishermen over the centuries have used this ability to their advantage. Dr Stuart Newson, population biologist of the British Trust for Ornithology (BTO), says cormorants have been recorded foraging for fish at depths of 105ft at the bottom of rivers or lakes. The Chinese have bred and reared generations of chicks for fishing. The cormorants are attached to a lead, with a ring around their neck, and away they merrily dive. “The ring means they are able to swallow small fish, but not the larger ones which the fishermen want, and which the cormorants regurgitate when they come to the surface,” explains Newson. “It was widespread practice in China in the past, but is declining as a tradition.”
King James I recognised these abilities, too, keeping his own Master of the Cormorants on the Thames and a semi-wild population of the birds for fishing purposes in St James’s Park, London.
But the overall attitude of fishermen has always been to regard them as a nuisance. “Historically, they have long been persecuted, especially on inland waters,” says Newson. “Their numbers have always been kept at really low levels across Europe. In France, they were down to as few as 60 birds at the turn of the 20th century. Since the 1970s attempts have been made to conserve their numbers by EU habitat directives, and they became officially protected in Britain via the 1981 Wildlife and Countryside Act.”
But as the European bird population has grown again, so has the irritation of hobby anglers and commercial fishermen. It is an offence to kill any wild bird, but licences are available from the Department for Environment, Food and Rural Affairs (Defra) to shoot to scare or kill cormorants, if all other attempts to prevent depletion of fish stocks have failed. More vocal members of the conservation lobby claim that these licences are handed out too easily; others point to research showing that cormorants tend to pick off smaller, sicker fish, which helps ensure a healthier overall fish stock.
It’s not that simple, says Dr Dave Carss, of the Centre for Ecology and Hydrology. “Scientifically, there is little evidence one way or the other to demonstrate the gross impact of the birds on fisheries,” he says. “But, like all predators, they are more likely to take sick, disadvantaged or unconditioned fish, so from that angle they can be seen to be beneficial.
“The other side of the coin is that there is an increasing number of them and they are almost exclusively fish-eating. Where there are large concentrations of shoaling fish, cormorants will be attracted to them, whether they are healthy or not.”
Although shooting works, it can be ineffective where cormorant numbers are high, according to advice from the Moran Committee Joint Bird Group, a platform formed in 1997 to act as a co-ordinating group for ornithologists, fishermen and scientists to strike a balance between the interests of birds and of fisheries and anglers. Often the cormorants will disappear for a few weeks, only to return.
Complete extermination by shooting is clearly not an option with a bird that enjoys protected status. Carss believes that, ultimately, fishing interests have to “learn to live with them and make fishing areas less attractive to them”.
Studies have shown that cormorant eyesight is not as good as was commonly thought and that the birds favour open waters, where prey is more visible. They can be discouraged by overhanging trees throwing shadows, the creation of reed beds and shallow areas acting as spawning grounds and offering refuge.
“Modern fisheries were often developed before cormorant numbers were rising,” says Carss. “If thought was given to structuring them with more natural cover, it would be a deterrent. Hatcheryreared fish also have less antipredator behaviour than wild fish. They are faster-growing and eat more, and are therefore more vulnerable to cormorants than the more cautious, slower-growing wild fish.”
Newson argues that although cormorant numbers appear to be flourishing, they are more vulnerable that they seem. The last wintering data from the BTO is from 2005-06, the year after Defra licensed a cull of up to 3,000 birds. Those figures highlighted a marked drop in wintering cormorants.
“It was the Government’s aim to reduce numbers, but the trouble is that the monitoring — and culling — was done in winter, when the population is swelled by continental birds, as well as our own coastal birds and those nesting inland,” he says. “If you take out a couple of thousand birds, it’s impossible to know which group you are affecting. Our traditional coastal cormorant population, which inevitably has lower chick survival rates because of the feeding hardships they endure, is showing a big decline in some of its older colonies.”
Newson worries that although these declines may not be directly attributable to increased culling, there is little monitoring data of cormorant breeding numbers. We could be sending these historic birds into decline without realising it.
If you have information about inland breeding cormorant colonies, particularly recently established ones, email: firstname.lastname@example.org.
For details on Intercafe, a pan-European initiative to reduce conflict between cormorants and fisheries, see www.intercafeproject.net.
Wetting their appetite: the cormorants’ diet has brought them into conflict with fishermen for centuries