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Home* Antarctic News → South Georgia’s alba­tros­ses are still suf­fe­ring from bycatch in fishe­ries

South Georgia’s alba­tros­ses are still suf­fe­ring from bycatch in fishe­ries

Tho­se who have the pri­vi­le­ge to have seen South Geor­gia with their own eyes will remem­ber the island as a wild­life para­di­se. Seals, pen­gu­ins, fly­ing sea­birds – they are all the­re. The colo­nies are huge­ly impres­si­ve.

And the­re have been good news about the con­ser­va­ti­on sta­tus of South Geor­gia in recent years. The reinde­er that Nor­we­gi­an wha­lers had intro­du­ced from 1911 were cul­led until 2014. In South Geor­gia, the reinde­er popu­la­ti­on had a den­si­ty of up to 85 ani­mals per squa­re kilo­met­re, in con­trast to about 5 per sq km in Spits­ber­gen. It does not sur­pri­se that the vege­ta­ti­on in South Geor­gia suf­fe­r­ed sever­ely from the con­stant tram­pling and gra­zing from thou­sands for reinde­er in tho­se are­as whe­re they exis­ted. This was evi­dent when you com­pared tho­se parts of South Geor­gia whe­re reinde­er roa­med the tus­sock grass with other are­as whe­re they never exis­ted. The era­di­ca­ti­on pro­ject gai­ned prio­ri­ty when the ongo­ing retre­at of gla­ciers threa­ten­ed to enable reinde­er to migra­te to other parts of the island which had been natu­ral­ly clo­sed of until now. Whe­re­ver pos­si­ble, reinde­er were her­ded and slaugh­te­red; else­whe­re, they were shot by hun­ters. The last ones were cul­led in 2014. Sin­ce then, the vege­ta­ti­on and accor­din­gly many bird spe­ci­es asso­cia­ted with the tus­sock gras com­mu­ni­ties can return to their ori­gi­nal habi­tat in tho­se are­as form­er­ly inha­bi­ted by reinde­er.

Reindeer, South Georgia

A view from the past: Reinde­er on South Geor­gia (St. Andrews Bay, 2009).

Get­ting rid of rats was ano­ther and much lar­ger chall­enge. The­se came also with the wha­lers to the island. They thri­ved soon in many are­as – a dis­as­ter for many ground-bree­ding sea­birds, mea­ning pret­ty much all of them (the­re are no trees on South Geor­gia). Rats take eggs and chicks from nests and bur­rows and they don’t even hesi­ta­te to have a go at chicks from lar­ge alba­tros­ses.

In a her­cu­lean effort that las­tet over seve­ral years, the South Geor­gia Heri­ta­ge Trust has era­di­ca­ted rats on South Geor­gia. The eva­lua­ti­on pha­se is still going on, but years of moni­to­ring have not shown any traces of rats still being pre­sent on the island. Birds such as the South Geor­gia pipit which had been rest­ric­ted to small off-lying islands for many deca­des soon star­ted to re-estab­lish them­sel­ves on the main island.

The reco­very of wha­le and seal popu­la­ti­ons after cen­tu­ries of inten­se cat­ching and hun­ting is also good news. Today, thou­sands of Fur seals crowd South Georgia’s bea­ches again. Some wha­le spe­ci­es will need cen­tu­ries to return to pre-indus­tri­al levels if they ever do, while others, noti­ce­ab­ly the Hump­back wha­le, make a swif­ter return. The over­all deve­lo­p­ment is posi­ti­ve.

But all the­se good news and suc­ces­ses don’t mean that ever­y­thing is as it should be. Bycatch in fishe­ries has been an issue for deca­des, being the reason for dra­ma­tic decli­nes of many sea­bird spe­ci­es not only in South Geor­gia, but in many are­as of the world. This includes ico­nic spe­ci­es such as the Wan­de­ring alba­tross and many of its clo­se rela­ti­ves. Also here, the­re have been regio­nal impro­ve­ments: in South Georgia’s waters, strict regu­la­ti­ons have brought major impro­ve­ments. Here, bycatch does not have a signi­fi­cant effect on popu­la­ti­ons any­mo­re, birds drow­ning on longli­nes are rare excep­ti­ons today. That is the good news. The bad news is that fishing ves­sels else­whe­re in the Sou­thern Oce­an (or else­whe­re, for that sake) ope­ra­te under much less strict regu­la­ti­ons and often ille­gal­ly. And many sea­birds tra­vel thou­sands of miles on their fora­ging trips. Regio­nal pro­tec­tion will not be able sol­ve the pro­blem.

As a result, in spi­te of regio­nal suc­ces­ses bycatch is still con­side­red the one big main thre­at for many sea­bird popu­la­ti­ons. Also on South Geor­gia, seve­ral alba­tross spe­ci­es are still decli­ning stron­gly – in a sta­te which is alre­a­dy con­side­red any­thing but sta­ble and healt­hy. Spe­ci­es inclu­ding Wan­de­ring, Black-bro­wed and Grey-hea­ded alba­tross are all lis­ted on the IUCN list at various levels of risk. And all of them are still losing indi­vi­du­als at an alar­ming rate, as is con­firm­ed by recent sur­veys..

Wandering albatross. Bird Island, South Georgia

Wan­de­ring alba­tross on nest on Bird Island, South Geor­gia.

The num­ber of Wan­de­ring alba­tros­ses bree­ding on South Geor­gia has decli­ned by 18 % in just 11 years, from 2003/04 to 2014/15. Spea­king in abso­lu­te figu­res, only 1278 were left out of 1553 in the begin­ning of the abo­ve-men­tio­ned peri­od. Black-bro­wed alba­tros­ses went through a very simi­lar deve­lo­p­ment with a loss of 19 %. For Grey-hea­ded alba­tros­ses, the situa­ti­on was even much more dra­ma­tic with a loss of a stun­ning 43 %.

And it is not that this deve­lo­p­ment star­ted at a healt­hy level in 2003/04. Popu­la­ti­ons have decli­ned at least sin­ce the 1970, when sci­en­tists star­ted to moni­tor them more regu­lar­ly. Today’s colo­nies are just a shadow of what they were when South Geor­gia and the Sou­thern Oce­an were still untouch­ed by man, befo­re wha­ling and seal­ing star­ted. Sal­ly Pon­cet and her co-aut­hors con­sider bycatch in fishe­ries still the main thre­at for South Georgia’s alba­tros­ses.

last modification: 2019-01-04 · copyright: Rolf Stange