Cull or cure: a bird’s-eye view for fish­er­men

The so­lu­tion to the cor­morant ‘prob­lem’ is in sight, re­ports Jack Watkins

The Daily Telegraph - Saturday - - Country -

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: stu­art.new­son@bto.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

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