Humans have forced cod to shrink in size by half since 1990s, scientists find
What over-fishing has done to the size of cod in just 30 years
- Excessive fishing has caused Baltic cod to undergo genetic changes, halving their size over the past 30 years.
- A study published in Science Advances is the first to demonstrate that decades of overfishing and environmental changes can profoundly alter the genetic makeup of a fully marine species.
- Researchers found a 48 per cent decrease in the asymptotic body length of Eastern Baltic cod between 1996 and 2019, with genetic variations indicating evolution driven by human interference.
- The study revealed that the genomes of fast-growing cod systematically differed from slow growers, with fast-growing individuals nearly disappearing from the Baltic Sea.
- This phenomenon is described as evolution in action driven by human activity, where the consistent removal of larger fish gives smaller, faster-maturing fish an evolutionary advantage.