The Caribbean monk seal went extinct mainly because humans hunted it intensively and overfished its prey. Its slow reproductive rate prevented depleted populations from recovering. This is SL and HL content within A4.2 Conservation of biodiversity.
The Mechanism of Extinction
The Caribbean monk seal (Neomonachus tropicalis) once lived throughout the Caribbean Sea, Gulf of Mexico and western Atlantic. European colonists and later commercial hunters killed large numbers for oil obtained from their body fat, as well as for meat and skins.
This overexploitation directly increased mortality. As the population became smaller, continued hunting removed individuals faster than reproduction could replace them.
At the same time, overfishing reduced populations of fish and other marine organisms eaten by the seals. Reduced food availability lowered survival and reproductive success, making population recovery even less likely.
| Anthropogenic factor | Effect on the seal population |
|---|---|
| Commercial and subsistence hunting | Directly reduced population size and removed breeding adults |
| Overfishing | Reduced prey availability and therefore survival and reproductive success |
| Human disturbance of coastal habitats | Disrupted resting and breeding sites |
| Slow reproduction | Prevented rapid recovery after population decline |
The last confirmed sighting was in 1952. After repeated surveys found no surviving individuals, the species was officially declared extinct in 2008.
A common misconception is that overfishing alone caused the extinction. It was an important contributing factor, but direct hunting was the principal cause; several anthropogenic pressures acted together until the remaining population was no longer viable.
Exam Technique
For an IB question asking you to explain this extinction, link each cause to its population-level consequence: hunting increased mortality, overfishing reduced food, and slow reproduction prevented replacement. Avoid merely listing threats; show the causal chain from human activity to declining population size and eventual extinction.