March 21, 2024 | npj Ocean Sustain | Source |
Introduction: Climate change significantly affects marine ecosystems, exacerbated by overfishing and habitat degradation, weakening the ocean's capacity to buffer against climate change impacts. Although oceans have absorbed roughly 28% of human-generated COâ‚‚ since 1750, current fishing methods disrupt critical biological carbon cycling processes. Researchers from the UK, Canada, Norway, and the USA examined how marine vertebrate depletion, damage to carbon-rich seabeds, and fuel-intensive practices—accounting for about 1.2% of global oil consumption with emissions rising 28% from 1990 to 2011—contribute to these disruptions.
Key findings: Marine fish significantly contribute to deep-ocean carbon sequestration through mechanisms like faecal pellet sinking and diel vertical migration, potentially accounting for over 20% of carbon sequestration. However, overfishing, combined with climate change and pollution, reduces marine resilience and alters carbon dynamics, threatening carbon sequestration, especially in critical mesopelagic fish populations.
In addition, bottom trawling disrupts seabeds, potentially releasing nearly 1.5 billion metric tons of aqueous COâ‚‚ annually, with 55–60% emitted into the atmosphere within 9 years. Harmful subsidies, especially fuel subsidies (22% of global fishing subsidies in 2018), enable extensive high-seas fishing, significantly increasing emissions. Targeting depleted stocks further increases fuel use per catch. Effective ecosystem-based fisheries management can rebuild biomass, enhance biodiversity, and secure sustainable livelihoods, but requires comprehensive global emissions reduction and careful socio-economic as well as environmental assessments to transition from bottom trawling.
Figure | Benefits of good fisheries management and issues associated with poor fisheries management practices.
