Question: I would like to farm with fish in a dam, but I need help to choose the right species. I’ve read that one should rather opt for fish species that already occur in the area. Can you assist, please?

Choosing a fish species to farm in terms of your area has 2 implications.

The first relates to the adaptability of the fish to the particular environment. This is mostly relevant in terms of climate and will also influence aspects like survival, feeding, growth and reproductive tempo (where relevant).

The second aspect relates to any possible impact the fish species will have on the natural environment, which is mostly an ecological issue. At this point, I would like to draw attention to an underlying ecological principle that can be applied in all aspects of agriculture.

Ecology as a term is often misused, but what is true, is that it is concerned with the “balance of nature”. It is important to realise, however, that this “balance” is not static, but dynamic. The concept becomes clear when one looks at the definition of ecology as a science.

Ecology is the study of processes (like births, immigration, emigration and disturbances) and interactions (like competition and predation) that determine the numbers and distribution of organisms.

When you bring a foreign fish species into an area, you change the dynamic of the system in terms of processes (immigration with an impact on the population dynamics of other species) and interactions (like competition for space or food with other species and/or direct predation).

You can, thus, irrevocably disturb the dynamic balance, or shift to a less desirable “balancing point”. Certain desirable species can, for instance, disappear from the food chain.

Also read:
Aquaculture: Keeping koi fish for fun and profit
Aquaculture: Fish farming offers possibilities
Aquaculture: Put food on the table and earn a promising extra income

• This article was written by Dionne Crafford and first appeared on Landbou.com.