The Herald (South Africa)

Pos­i­tive use of alien bass beats erad­i­ca­tion at­tempts

- Ecology · St Albans

THE sense­less mur­der of an­gler Clint Ovren­ovits at Swartkops River this week has shocked the com­mu­nity at a time of year when all we want is to re­lax and en­joy what the fes­tive sum­mer sea­son has to of­fer.

Out­stand­ing po­lice work has al­ready seen sus­pects be­ing ap­pre­hended, but it will not bring Clint back.

This has been a cold-blooded killing of an in­no­cent per­son mind­ing his own business and it ap­pears that common rob­bery and theft of a mo­tor ve­hi­cle was the mo­tive.

Mean­while, there are many farm dams in and around Port El­iz­a­beth that have healthy bass pop­u­la­tions.

That they are mostly on pri­vate land needs to be re­spected and, with the cor­rect ap­proach, ac­cess can be gained in or­der to fish th­ese lit­tle trea­sures.

Re­cently I was sent a pho­to­graph of a healthy large­mouth bass caught in the St Al­bans area by Gra­ham Mool­man.

Bass are fe­ro­cious preda­tors that tol­er­ate no com­pe­ti­tion. They guard their nests where the eggs have been fer­tilised and at­tack any­thing that moves there.

Th­ese fish are caught on any ar­ti­fi­cial bait pre­sented mim­ick­ing any­thing edi­ble or pos­ing a threat.

Most dams have awe­some struc­ture that al­lows bass to breed; how­ever, no other fish make it in the same en­vi­ron­ment.

For this rea­son bass are seen as alien and there are moves to erad­i­cate them from wa­ter sys­tems around the coun­try.

Pre­vi­ously, I have writ­ten about this erad­i­ca­tion strat­egy and the use of dif­fer­ent tech­niques. But I fail to see how it can be achieved. The side-ef­fects of dam­age done to the tar­geted sys­tems will also be ir­re­versible for all forms of wa­ter life that live there.

We need to move on with ideas that will look at the pos­i­tive util­isa- tion of th­ese so-called alien fish species.

Trout is another species that has been in­tro­duced to this coun­try and both th­ese species are sought after an­gling species that gen­er­ate a huge sale of tackle and ac­ces­sories amongst many other forms that add to the land’s econ­omy.

Bass are well pop­u­lated and the erad­i­ca­tion idea is just not pos­si­ble.

Ways to save threat­ened species will have to be de­vised and im­ple­mented in sys­tems where alien species must not be in­tro­duced.

The law of grav­ity and rivers and ir­ri­ga­tion dams that over­flow into wa­ter sys­tems will al­ways be sources that con­tam­i­nate lower ly­ing rivers with alien fish, and hence the im­pos­si­ble task to con­tain th­ese fish.

The laws de­signed to pro­tect wa­ter sys­tems from the in­tro­duc­tion of alien species has failed too, as na­ture works 24/7.

Tar­get­ing th­ese pri­vate dams and erad­i­cat­ing the species there is on the cards and again we stand the chance of los­ing pre­cious recre­ational fa­cil­i­ties that also gen­er­ate in­come for land own­ers across the coun­try.

On pa­per th­ese ideas shine but they are sim­ply not prac­ti­cal. The breed­ing of sex­less fish means pop­u­la­tions can be bet­ter con­trolled as is the case with trout in the form of the “triploids”.

Th­ese fish that es­cape can then never pose a long-term threat to the in­vaded sys­tems by es­tab­lish­ing new com­mu­ni­ties that well de­velop there.


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