Conservation issues
Dam, Barrages, and Water Abstraction: The Gharial is a riverine species and the building of dams negatively affects it in two ways: 1) by turning suitable river habitats into marginal/unsuitable lakes (reservoirs), and 2) by altering the quantity and quality of water available to downstream river sections. Dams severely affect stream flow volumes, timing and amplitude of water level changes, water quality and the transportation of sediments important for beach replenishment. Dams also form impassable barriers, or possibly one-way (downstream only) barriers to Gharial dispersal (and its aquatic prey), isolating populations and preventing interchange among sites.
Fishing: Commercial and subsistence fishing using gill nets affects all existing Gharial populations. Although fishing is prohibited in Protected Areas, the laws are inadequately enforced and fishing goes on unabated. Gharial, with its long, toothy rostrum is particularly vulnerable to entanglement in nets, where it is frequently trapped underwater and drowns. Entangled Gharial that do not drown are commonly killed or have their rostrums chopped off to disentangle nets and perhaps, in retaliation for damaging nets. Gharial of all sizes are vulnerable to this threat; the impact on populations is particularly severe when mature adults are killed. Indirectly, fishing also affects Gharial by reducing fish stocks and changing the prey size and species composition (usually towards smaller and less commercially desirable species).
River bed cultivation: This activity, which is rampantly practiced in many other rivers of the Ganges and its tributaries, has effectively prevented the survival of the Gharial over large tracts of the species former habitat. River bed cultivation simply alienates Gharial from the terrestrial component of its habitat leading to desertion and migration.
The problem is further complicated by the apparently traditional private ownership of portions of the riverbed.
Sand mining: Commercial sand mining is widespread along many parts of most of the rivers. Removal of sand from riverbanks disrupts Gharial behavior and may even force local populations to desert the area. Sustained mining activity may destroy vital basking and nesting sites and may also result in direct mortality of eggs during the nesting season. Disturbance and disruption of basking sites reduces habitat quality for the Gharial and may compromise their thermo-regulatory behavior, further affecting feeding, growth and reproduction.
Pollution: Throughout much of the Subcontinent, riverine habitats of Gharial are widely polluted by agricultural pollutants (insecticides, fertilizers, herbicides) that are known to reduce reproductive success and cause developmental anomalies in other crocodilians while the impact on the aquatic ecosystem is unknown. In addition, pollution reduces productivity and fish stocks, reducing food resources for the Gharial. Pollution is rapidly compromising the fate of millions of riparian people traditionally and wholly dependent on river water for household use.
Egg harvesting: Egg harvesting for subsistence food use by riparian residents at some Gharial locations directly increases egg mortality, reduces recruitment, and may also facilitate additional predation by natural nest predators such as Jackals and Monitor Lizards. Under normal circumstances most crocodilian populations are little affected by some loss of eggs and nests. However, at the current highly depleted and fragmented status of Gharial, this additional loss may be severe, often completely decimating a population’s annual reproductive effort.
Riverbank disturbance: Riparian seasonal agriculture (melons, gourds, mustard and wheat), grazing, and other miscellaneous human activities such as ferries/fords, wood-cutting and bathing/laundering clothes disturb Gharial and may disrupt basking and nesting sites.
Fishing: Commercial and subsistence fishing using gill nets affects all existing Gharial populations. Although fishing is prohibited in Protected Areas, the laws are inadequately enforced and fishing goes on unabated. Gharial, with its long, toothy rostrum is particularly vulnerable to entanglement in nets, where it is frequently trapped underwater and drowns. Entangled Gharial that do not drown are commonly killed or have their rostrums chopped off to disentangle nets and perhaps, in retaliation for damaging nets. Gharial of all sizes are vulnerable to this threat; the impact on populations is particularly severe when mature adults are killed. Indirectly, fishing also affects Gharial by reducing fish stocks and changing the prey size and species composition (usually towards smaller and less commercially desirable species).
River bed cultivation: This activity, which is rampantly practiced in many other rivers of the Ganges and its tributaries, has effectively prevented the survival of the Gharial over large tracts of the species former habitat. River bed cultivation simply alienates Gharial from the terrestrial component of its habitat leading to desertion and migration.
The problem is further complicated by the apparently traditional private ownership of portions of the riverbed.
Sand mining: Commercial sand mining is widespread along many parts of most of the rivers. Removal of sand from riverbanks disrupts Gharial behavior and may even force local populations to desert the area. Sustained mining activity may destroy vital basking and nesting sites and may also result in direct mortality of eggs during the nesting season. Disturbance and disruption of basking sites reduces habitat quality for the Gharial and may compromise their thermo-regulatory behavior, further affecting feeding, growth and reproduction.
Pollution: Throughout much of the Subcontinent, riverine habitats of Gharial are widely polluted by agricultural pollutants (insecticides, fertilizers, herbicides) that are known to reduce reproductive success and cause developmental anomalies in other crocodilians while the impact on the aquatic ecosystem is unknown. In addition, pollution reduces productivity and fish stocks, reducing food resources for the Gharial. Pollution is rapidly compromising the fate of millions of riparian people traditionally and wholly dependent on river water for household use.
Egg harvesting: Egg harvesting for subsistence food use by riparian residents at some Gharial locations directly increases egg mortality, reduces recruitment, and may also facilitate additional predation by natural nest predators such as Jackals and Monitor Lizards. Under normal circumstances most crocodilian populations are little affected by some loss of eggs and nests. However, at the current highly depleted and fragmented status of Gharial, this additional loss may be severe, often completely decimating a population’s annual reproductive effort.
Riverbank disturbance: Riparian seasonal agriculture (melons, gourds, mustard and wheat), grazing, and other miscellaneous human activities such as ferries/fords, wood-cutting and bathing/laundering clothes disturb Gharial and may disrupt basking and nesting sites.