Population growth: Mexico has increased its population of 81,249,000 inhabitants in 1990 to 97,361,711 inhabitants in 2000, with a growth rate of 1.60% (INEGI, 2000). The population growth has produced a rapid urban expansion, requiring major quantities of water extracted from the rivers as sources of fresh water for cities. The great rivers in Mexico are being or already are affected due that the subterranean waters have been depleted or have to go through a tight management for not finishing them. Together with the rapid population growth comes the waste waters from cities and towns which are loaded with organic mater, contaminants and trash.
Increase on the use of water for irrigation of crops. Any medium sized river is being used for irrigation. This water is returned to the environment loaded with agricultural contaminants (insecticides and fertilizers).
Large scale destruction due to the use of ancient culture methods such as slash and burning of the jungles, woods and riparian vegetation. This combined with the opening of new lands for cattle growth. The irrigation of fields on step areas creates a major problem of erosion of river basins and the deposition of the eroded material destroys areas once used by river otters.
Using the fields for the extraction of oil, the land filling of wetlands with the same purpose and the destruction of mangrove and marshes for shrimp aquaculture is also destroying river otter's habitats.
River contamination with industrial, agricultural and municipal wastes, threaten the food chain of which river otters depend. Mexican industrial development is vital for Mexican Government because it creates more jobs for a growing population; but it is also a threat to river otter habitats, due that industry needs large quantities of fresh water (in example: cleaning of electronic components for computers). Industrial development has a large impact on small urban areas, the rivers becoming drainages loaded with pollution.
Land ownership is a problem that creates civilian and ecological difficulties, when landless people from other states or region invades areas in good state of conservation to open them for agriculture using slash and burn techniques, they are devastating everything to obtain the maximum yield in less time. Once that land is render sterile it is abandoned, leaving eroded and unproductive lands.
Fishing methods such as the use of venoms extracted from toxic plants, small quantities of TNT (which is prohibited in México), quick lime and electrocution (with dynamos) have caused unbalances on complete river ecosystems.
The creation of new fishing camps and the increase in the fishing power along the coast of Baja California Peninsula will make very difficult that sea otters will reestablish naturally in México. The large use of gillnets along the Pacific coast of Baja California had produced the entanglement of sea otters (Gallo-Reynoso and Rathbun, 1997). There is an urgent need of establishing regulations on the use of this gillnets around specific areas where sea otters have been observed regularly. There is only one Biosphere Reserve (Reserva de la Biósfera del Vizcaíno) with enough coastal areas that would be able to protect an small but viable population of sea otters. Even though rules shall be well applied.
There is also the urgent need of establish campaigns for a "new water culture", on which water uses should produce a minimum or none effect in the riparian environment.
There is little knowledge on the influence that pollution have on river otters. There is no studies on scats or in the river courses that would indicate the pollution load in areas where river otter populations are stable, and in those in which river otter populations are decreasing.
River otters are still hunted for their fur, mainly to supply family needs in the poorest areas. River otter cubs are also used as pets in some coastal areas of Mexico. There is no large scale capture and there is no black market for selling their furs. Even though furs have been found in the artisanal industry and tourists stores (wallets, jackets, purses made of river otter fur).
Identification sheet
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