The MarVivo Conservation Thesis

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.

“Recent studies suggest that sharks and rays are important elements within their foodwebs, and that reductions in the size of populations of large sharks can initiate trophic cascades through top-down effects”

(e.g. Stevens et al. 2000; Myers et al. 2007; Ferretti et al. 2010).

The importance of this imbalance in the trophic levels is that reef fishes are the reefs’ cleaners. They feed on algae that, in their absence, overwhelms the “good” bacteria that support coral polyps. The first stage to coral-bleaching is the evidence of these algae. Once the reef dies, the cascade reverses to a bottom up collapse of the entire food chain thereby taking down the entire ecosystem.

If we are to save the oceans, we must save MANGROVES and SHARKS.
This is the goal of MarVivo within the Eastern Tropical Pacific Seascape.