3 Jul 2019 - The smallest forms of life are essential for the health of the entire marine food web, including many of the fish that are in the greatest commercial demand. A new study suggests that focusing on individual fish populations is not an effective strategy to protect ecosystems from the damage and insecurity associated with overfishing.
“In simple terms, to successfully manage fisheries in an ecosystem, the rate of removal for all fishes combined must be equal to or less than the rate of renewal for all those fish,”said study co-author Jason Link, who is the senior scientist for ecosystem management at NOAA Fisheries.
The researchers propose that three particular indices could be monitored, using widely available catch and satellite data, to determine when ecosystem overfishing is occurring. These factors include: when the total catch of all fish is declining, the total catch rate or fishing effort required to get that catch is declining, and the total landings relative to the production in that ecosystem exceed suitable limits.
“Detecting overfishing at an ecosystem level will help to avoid many of the impacts we have seen when managing fished species on a population-by-population basis, and holds promise for detecting major shifts in ecosystem and fisheries productivity much more quickly,” said Link.
The suggested thresholds for each index are based on the known limits of the productivity of any given part of the ocean.
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