Massavrekte van robwelpies ondersoek

Tussen 6 en 8 Oktober is honderde nuwe aborsies aangemeld – te veel om te kan tel.
Elvira Hattingh
Elvira Hattingh – ’n Ondersoekspan het begin om ongewone vrektes onder Kaapse pelsrobbe te ondersoek nadat klaarblyklik duisende wyfies vanjaar hul welpies teen die Namibiese kus geaborteer het, terwyl talle robbe ook gevrek het.

Die massa robvrektes by Pelikaanpunt word as ’n ongewone gebeurtenis beskou, wat mariene wetenskaplikes in Namibië en Suid-Afrika bekommerd maak.

Volgens ’n mediaverklaring deur die Namibiese Dolfynprojek (NDP) en Ocean Conservation Namibia, het ongewoon maer wyfies vanjaar by die kus aangekom en honderde van hulle, indien nie duisende nie, het geaborteer. Die strande by Pelikaanpunt lê glo besaai met die oorskotte van geaborteerde pelsrobfetusse.

Ocean Conservation Namibia se mnr. Naudé Dreyer was glo die eerste om dit op te merk. “Aanvanklik het ek eers net ’n paar dooie, vroeggebore welpies laat in Augustus opgemerk en toe ook middel-September.

“Enkele vrektes is nie ongewoon nie, maar verlede week toe ek na Pelikaanpunt terugkeer, het ek honderde geaborteerde fetusse in een dag gesien. Dit is toe dat die gevaarligte vir my begin flikker het,” het hy verduidelik.

Tussen 6 en 8 Oktober het Dreyer honderde nuwe aborsies aangemeld – “te veel om te kan tel”. Hy skat dat meer as 350 jong robbe en volwasse robbe ook gevrek het. Die vrektes is meer as normaal en wek kommer.

Die ondersoekspan word gelei deur Dreyer, wat monsters van die robbe versamel. Hy werk saam met dr. Tess Gridley en dr. Simon Elwen van die NDP – beide van die departement plant- en dierkunde aan die Universiteit Stellenbosch – asook dr. Brett Gardner, ’n veeaarts van Suid-Afrika.

Biologiese monsters sal gebruik word om die oorsaak van die vrektes vas te stel, maar dr. Gardner meen daar kan verskeie oorsake wees. “Die lys van moontlike oorsake is lank en hoë aborteringsyfers word dikwels deur meer as een faktor veroorsaak. Daar is dus verskeie oorwegings . . .”

Dr. Gridley het bygevoeg dat beide Namibiese en Suid-Afrikaanse owerhede bedag moet bly en die robbe se bevolkings bly monitor waar hulle oraloor suider-Afrika voorkom.

“’n Sekere aantal sterftes vorm ’n normale deel van die robbe se lewensiklus en is te wagte. Wat kommerwekkend is, is as daar ’n hoë getal aborsies is wat terselfdertyd gebeur. Die impak van die vrektes onder Pelikaanpunt se kolonie en dalk elders, mag dalk vir jare vorentoe nog gevoel word.”

Tydens ’n massavrekte in 1994 het ’n geraamde 10 000 robbe gevrek en 15 000 fetusse is geaborteer. Die destydse verskynsel het te make gehad met hongersnood, waarskynlik weens ’n vistekort, asook ’n sekondêre bakteriese infeksie.

Kaapse pelsrobwyfies is die mees algemene mariene dier wat langs die Suid-Afrikaanse en Namibiese kuslyn te sien is, waar dit endemies voorkom. Tydens hul broeiseiseon – gewoonlik tussen middel November en vroeg Desember, gee duisende wyfies tegelykertyd geboorte, waarna die paarproses opnuut begin.

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