ALBUQUERQUE, N.M. — Freshwater ecosystems occupy 1% of Earth’s area, “but they support more than 126,000 species of fish and plants worldwide and feed about a billion people,” said Tim Lyons, a species survival officer with the International Union for the Conservation of Nature.
“Unfortunately, they are one of the most threatened ecosystems on this planet, because we rely on freshwater for literally everything,” he said.
The International Union for the Conservation of Nature compiles the Red List, a growing database that assesses the extinction threat faced by plants, animals and fungi around the world. It categorizes those threats as vulnerable, endangered or critically endangered.
Lyons, one of three of the group’s officers now assigned to the ABQ BioPark, recently led a Red List Review Workshop to assess the threat of 210 species of freshwater fish in Central America.
He noted that a number of fish species in Central America are also found in the fresh waters of Mexico, and that “a lot of species are closely related to what occurs right here in the Rio Grande Basin, including species of minnow, sucker and some cichlids.”
About 30% of the Central American fish species assessed during the review were threatened with extinction to some degree. What’s important for New Mexico, Lyons said, is that the primary threats to fish populations in Central America and Mexico are the same as threats to fish species in New Mexico, including the Rio Grande silvery minnow, the Zuni bluehead sucker and the sturgeon.
Among these threats are the placement of dams that restrict fish species’ natural range; agricultural runoff containing fertilizers, herbicides and pesticides; sediment loading that occurs when land is cleared for agriculture and increased amounts of sediment are carried by the rain into freshwater sources; and the diversion of fresh water from lakes, streams and rivers for agricultural irrigation.
Lyons said another huge problem is the unintentional hybridization of fish populations that occurs when closely related species of fish mix and produce offspring.
For example, he said, in the waters flowing through Mexico’s Sierra Madre, there are 16 species of native trout, “which are highly localized species, and if brook or rainbow trout get in there, those distinct species will be lost in a matter of years.”
Likewise, the same problem exists among trout in New Mexico’s Rio Grande Basin.
“If the intrinsic value of that biodiversity gets lost, then the species is lost because of genetic introgression,” Lyons said. “It’s also important to consider that some of these species may be better suited to aquaculture and have better growth potential in captive settings, or may have better feed conversion rates. If we lose that biodiversity, it’s gone forever and we’ll never know.”
The workshop in Albuquerque was notable because it was the first time that fish experts from across Central America were in the same room. As a result of that interaction, they committed to form a freshwater conservation working group that will meet annually “to facilitate conservation on the ground, and encourage collaboration among universities and participating parties to actually do conservation planning and put it into action,” Lyons said.
ABQ BioPark Director Baird Fleming said the International Union for the Conservation of Nature’s role at the BioPark has increased. The species survival officers, previously assessors, now train other Red List assessors, and they have been trained to do conservation planning and conservation action for governments and nonprofit, nongovernmental organizations.
“The BioPark just got Red List partnership status,” Fleming said. “There are less than 15 partners in the world, and we are the only zoological institution. It’s very prestigious for Albuquerque.”
Being a partner means that “Albuquerque now has a seat at the table and has voting power in how the IUCN moves forward into the future,” Lyons said.