Mangroves are the nurseries to a significant portion of all marine life. Without urgent and robust intervention in their conservation, we face an imminent collapse of all marine ecosystems globally. The role of sharks in a healthy marine ecosystem may be less obvious, but there is a growing body of research that demonstrates that high density fish populations depend on high density shark populations – not the reverse as would seem logical.
This phenomenon is explained by the fact that sharks are slow to mature to sexual maturity (6-10 years) and have relatively few offspring (a dozen on average). In contrast, all other levels of the food chain mature quickly (1 year on average) and have hundreds, thousands, or even millions of offspring. This means that a high shark population can never eat itself out of existence.
The reverse is true for the food they prey on – the “meso-predator” level such as snapper, grouper, jacks, etc. In the absence of a large shark population, this meso-predator population can explode. While this may be good news for the fishing industry, it is short-lived. Within five years or less, the meso- predator population can deplete their food source – reef fish.