Wetenskaplikes ontdek seeswaeltjies broei in die winter

4x4-voertuie hul grootste bedreiging
Wetenskaplikes het onlangs bevestig dat Damara-swaeltjies in die hart van die winter, eerder as om te migreer, op Hottentotsbaai se soutvlaktes broei.
Elvira Hattingh
Wetenskaplikes het pas ontdek dat ʼn beduidende aantal Damara-seeswaeltjies – anders as wat tot dusver geglo is – nie tydens die winter vanaf Namibië na sentrale Afrika migreer nie.

Baie van hierdie bykans bedreigde swaeltjies bly in Namibië aan en broei dwarsdeur die winter.

Lüderitz Marine Research sê wetenskaplikes het onlangs bevestig dat die swaeltjies in die hart van die winter op Hottentotsbaai se soutvlaktes, wat sowat 50 km noord van Lüderitz geleë is, broei.

“Danksy ʼn rare kombinase van goeie weer, ʼn ervare span en die tydige uitreiking van permitte vir die Sperrgebied wat ons moes besoek, asook goeie 4x4-duinryers met goed toegeruste voertuie, kon ons die soutvlaktes oor die afgelope dae verken,” het die organisasie op hul Facebook-blad gesê.

Die navorsingspan sê hulle het seeswaeltjies aangetref wat vroeg in Julie in ʼn soutpan in die gebied broei. Die pan is sowat 24 km lank en 4 km tot 5,5 km breed.

“Daar was volwasse swaeltjies, jong swaeltjies en kuikens teenwoordig wat pas uitgebroei het. Nessies met eiers is ook gevind.

“Sommige voëls is gevang en gering vir verdere, langtermynmonitering, as deel van die nasionale aksie plan vir die Damara-seeswaeltjies.”

Lüderitz Marine Research sê binne die drie dae wat die navorsing gedoen is, het die span meer as 100 km binne die soutpan geloop – in parallelle stroke, sowat 300 m weg van mekaar.

ʼn Navorsingsartikel sal na verwagting binnekort oor die jongste bevindinge gepubliseer word.

BEDREIG

Die grootste bedreiging vir die voortbestaan van die Damara-seeswaeltjie, is die beweging van 4x4-voertuie langs die Namibiese kus, waar eiertjies stukkend en kuikens vrekgery word.

Navorsers verwag dat die voëltjie se voortbestaan in die toekoms voortdurend hierdeur belemmer sal word – oral buiten daar waar kolonies hulle op die mees afgeleë plekke vestig.

Plaaslik word hierdie seeswaeltjie as naby-endemies en ook naby-bedreig in Namibië beskou, omdat meer as 80% van die spesie in die somer teen die Namibiese kusgebied broei, voor van hulle vir die winter na sentraal-Afrika – Nigerië en Ghana – migreer.

Wetenskaplikes weet van 70 kolonies wat hulle jaarliks in Namibië vestig. Die Damara-seeswaeltjie geniet reeds vir baie jare ‘n spesiale bewaringstatus in Namibië en van die plaaslike kolonies se broeihabitat is in beskermde gebiede geleë. Na raming is hul plaaslike bevolkingsyfers tans stabiel.

In ‘n onlangse navorsingstuk deur RE Simmons, RJ Braby en SJ Braby, sê die navorsers hul getalle in Suid-Afrika is egter kritiek laag, alhoewel dit wêreldwyd as naby-bedreigd beskou word.

In Namibië word hulle ook bedreig deur ‘n groter teenwoordigheid van jakkalse en seemeeue teen die kus – wat gelok word deur ‘n groeiende aantal robkolonies, wat op die beurt weer deur hengelbedrywighede gelok word.

Die ontwikkeling van residensiële gebiede teen die kus is ook ʼn bedreiging. Volgens die navorsers het die ontwikkeling van Dolfynstrand in 2005 ʼn belangrike gebied vir voëls asook ʼn broeihabitat vir Damara-seeswaeltjies in ʼn hoë-inkomste residensiële ontwikkeling omskep.

“Die seeswaeltjie-kolonie, wat uit 32 broeipare bestaan het, het sedertdien nie weer na die gebied teruggekeer nie,” word verduidelik. – [email protected]

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