overfisking

Overfisking, or overfishing, occurs when the rate of harvesting a fish stock exceeds the population’s natural replenishment, leading to a sustained decline in abundance and long-term reductions in yields. It is a central concept in fisheries science and policy, used to describe unsustainable pressure on marine resources.

Causes include advanced fishing technology that enables catching large quantities, subsidies that encourage high effort, open-access or poorly regulated fisheries, weak enforcement, and gaps in stock assessment. Insufficient data on stock size and reproduction can mask the true level of exploitation, delaying corrective management.

Impacts of overfisking are broad. Ecologically, reduced stock abundance can alter food webs, reduce ecosystem resilience, and increase vulnerability to environmental change. Economically, it can cause revenue losses, job instability, and community decline in fishing regions. Socially, it may erode cultural practices and local livelihoods. Bycatch and discards further harm ecosystems and reduce the efficiency of otherwise sustainable fleets.

Management responses aim to align harvest with sustainable yield. Tools include stock assessments, the precautionary principle, catch quotas, effort controls, size limits, gear restrictions, seasonal closures, and area protections. Rights-based approaches, such as catch shares or access rights, can improve incentives for sustainable fishing. Ecosystem-based management seeks to consider predator–prey relationships, habitat quality, and cumulative impacts across sectors.

Notable historical examples include the collapse of the Northwest Atlantic cod stock in the early 1990s, which led to a large moratorium and economic hardship. In other regions, some stocks have recovered under science-based management, while others remain overfished or require rebuilding plans.