Pelican

The genus Pelican (Pelecanus) belongs to the order Pelecaniformes and the family Pelecanidae. While not pests in traditional crop agriculture, they are recognized as significant biological pests within the aquaculture industry, frequently causing substantial economic disruption to commercial fisheries and fish ponds.

The primary economic damage is caused by the predation of fish. Pelicans are highly efficient hunters and are capable of consuming large quantities of commercial fish species daily. Their diet is broad, but in fish farming environments, they disproportionately target stocked fish, significantly reducing the yield per hectare of the aquaculture facility.

Regarding their biology, pelicans are social birds that often hunt in coordinated groups. This behavior allows them to surround schools of fish, effectively corralling them into shallow areas where escape is impossible. During migration periods, their sudden presence in large numbers can deplete a small pond's inventory in a matter of days.

Beyond direct consumption, the harm includes physical injury to fish that escape a pelican's grasp. These wounds often lead to secondary bacterial or fungal infections. Furthermore, large flocks significantly contribute to the biological pollution of pond water through excrement, which increases nitrogen and phosphorus levels, potentially triggering harmful algal blooms.

To mitigate these losses, fish farmers employ several protection strategies. Physical exclusion using overhead netting is the most effective measure, though often costly. Other approaches include the use of acoustic repellers, light-based deterrence systems, and the maintenance of marginal vegetation to reduce the pond's appeal for landing and takeoff, thereby minimizing the impact on stock.