By Jonny Lupsha, Wondrium Staff Writer
Conservation biology concentrates on how to preserve ecosystems and save species. If conservation needs are met, marine fisheries are resilient due to the biodiversity that had been present before human involvement. A newly created, four-nation marine corridor will help.
The presidents of Colombia, Costa Rica, Ecuador, and Panama announced at Glasgow’s COP26 summit on climate change that a new conservation effort will run through all four countries. The ambitious “fishing-free corridor” will run from Ecuador’s Galapagos Islands to Colombia’s Malpelo Island and the Cocos and Coiba Islands in Costa Rica and Panama, and be marked off-limits to industrial fishing.
If successful, the corridor could reverse the damage done to parts of the eastern Pacific ecosystem and could restore the numbers of many aquatic species. In his video series Earth at the Crossroads: Understanding the Ecology of a Changing Planet, Dr. Eric G. Strauss, Presidential Professor in Ecology at Loyola Marymount University in Los Angeles, said fisheries ecology is a clear microcosm for human effects on ecosystems.
This Mess We’re In
“Fisheries ecology has been a source of direction for understanding the impact on human ecosystems, partly because we do stuff to ocean ecosystems we would never do to terrestrial ecosystems,” Dr. Strauss said. “When we fish with big net systems, we essentially are taking chains and cables and just dragging them along the ocean floor, sweeping up everything that is along that area.”
Dr. Strauss compared it to taking a net with a one-mile circumference on the ground, closing it, and catching everything that’s in there while knocking down trees, bushes, and other plant life. Additionally, he said, when we eat animals from land ecosystems, we usually eat from the middle of the food chain—grass eaters like cattle and pigs. From the ocean, we eat the rarest top predators.
“It’s equivalent of us in a terrestrial environment deciding we’re only going to eat coyotes, grizzly bears, and lions.”
Packed like Sardines
Overfishing can be a part of marine ecosystems, but it doesn’t hold exclusive rights to affecting them.
“Recent work by Stephen Palumbi—leading a team from Stanford University, Oregon State, and the University of Washington—[has] discovered that the resiliency of fishing grounds to recover from human overfishing is in many ways contingent upon their health preceding the human invasion,” Dr. Strauss said. “The recovery, resistance, and reversibility are key features of an ecosystem’s overall resilience.”
According to Dr. Strauss, Professor Palumbi’s team analyzed populations of anchovies and sardines at the landings of the most important fisheries. They found that the landings can differ by millions of metric tons per year, and that when anchovies are up, sardines are down, and vice-versa. What was going on?
“As they analyzed longer time scales, it was revealed that these cycles are actually driven by natural climate variation,” he said. “In these analyses of the anchovy and sardine harvest, they needed to factor in the natural fluctuations and resiliencies that were part of that system.
“Although humans are adding to the challenge, part of the natural fluctuations and the way that those ecosystems are structured has to do with the fact that the anchovies and the sardines are actually going to covary on their own.”
Additionally, these studies of fisheries recovery showed that ecosystems with high initial biodiversity could better withstand human impact. The richness of species in a given area made it more likely to withstand collapse from human fishing, while those that were the most diverse prior to collapse were most likely to recover quickly after restrictions on fishing were imposed.
Four Latin American countries have announced plans to preserve their marine ecosystems; time will tell if their efforts and the region’s biodiversity are enough.