Anglers’ concerns over cormorants depleting fish stocks are self-serving and disingenuous. PETER FROST explains
Forty years ago walking beside a lake at Rickmansworth in north London and a long way from the sea I spotted a black heron shaped bird. The only thing similar I could find in my bird book was indeed a black heron (below).
A native of Africa, this very rare bird had only been seen once or twice in Britain. Even I realised my identification was probably way off beam.
A wiser and more experienced bird-watcher friend soon put me right. This rare visitor to an inland lake was a cormorant.
I knew more about cormorants in China than I did in Britain. Chinese fisher-folk used this skilful fishing bird to catch fish for them. The tame birds are fitted with a neck ring to stop them swallowing the bigger fish they catch.
Like many other birds cormorant behaviour had changed dramatically over recent decades.
In Britain the cormorant was almost exclusively a coastal breeder until 1981, when an inland tree-nesting colony became established at Abberton reservoir in Essex.
This colony was later found to comprise of cormorants of a continental sub-species.
By 2012 cormorants have bred at 89 inland sites in England, although breeding at many of these sites was of a single nest or was only for a year or two.
As cormorants moved inland anglers have been pressing the government to do something about the birds.
Most anglers now believe that cormorant numbers are now out of control. Many groups, including the Angling Trust and the Salmon and Trout Association, are lobbying the Department for Environment, Food and Rural Affairs (Defra) to control fish-eating birds.
They want the law changed so that cormorants can be killed under a general licence, similar to those issued for the control of crows or wood pigeons.
The complaint is that current licences allow holders to kill only a handful of birds a year — not nearly enough when inland cormorant numbers over winter have increased from around 2,000 in the early 1980s to nearly 25,000 today.
But allowing cormorants to be culled like crows has alarmed naturalists and bird watchers.
“This would be a new departure,” said Grahame Madge of the RSPB. “It would be the first time a provision had been made to cull a species for sport.
“The population of cormorants is far lower than wood pigeons, which are almost in their millions. If it were introduced, it would be difficult to monitor how many cormorants were being killed and it could result in the population being reduced.”
The RSPB is instead calling for anglers and fisheries owners to use non-lethal tactics to protect fish stocks.
Why have the cormorants moved inland? One theory is that commercial inshore overfishing has depleted fish stocks. Some say they have been lured inland by the many trout farms that offer cormorants free dinners.
The migration inland has also affected the birds’ diet.
A adult cormorant needs around 300g (10oz) of sea fish a day. But freshwater fish are less fatty, meaning a bird will need to consume around double this amount.
The number of cormorants that can be legally killed a year has been increased from 500 to 3,000, a level that troubles the RSPB, which disputes claims the birds are responsible for a significant decline in river fish.
“If there are cormorants at a site, most naturalists would say that means there are fish there,” Madge said. “If they were eating all the fish, they would decline in numbers.
“There is no science to back up claims the situation is getting worse, but anglers want to reach for the shotgun.”
Historically, the cormorant population in Britain has been kept at a low level due to persecution by humans and through reduced breeding resulting from pesticide pollution. Today rivers and other inland waters are far less polluted.
Following protective legislation against persecution in Denmark and Holland in the 1960s, the European population increased rapidly and continental birds started to extend their wintering range into Britain and Ireland. Nigel Farage wouldn’t like that.
Research has found that the timing of breeding between the inland and coastal breeding birds is very different.
Coastal birds breed within a very narrow period, with all chicks all hatching at a similar time.
In contrast, inland cormorants have a long breeding season. The large difference in timing of breeding within an inland colony means that competition for food when chicks are large is reduced.
This article first appeared in the Morning Star 24 April 2015.
Note: Not all the pictures on this blog are of British birds or indeed British shooters.