Colony-level cognition

20,000 people obtained a living from this fishery. But since then, catches have fallen to around 5,000–10,000 tons but prices have risen substantially, maintaining the incentive to pursue this declining species. Overfishing, in combination with habitat loss, pollution, the damming of rivers and climate change affecting ocean currents, have all contributed to the sharp decline in eel populations. The stock of juvenile eels is estimated to have declined by 95–99 per cent since 1980, Cites say. However, eels have a high survival rate, meaning that wild populations could recover if fewer young eels were caught.