Last fishing season, I discovered populations of wild rainbow trout on the Rio Capulin near Gallina and the Rio Tusas near Tres Piedras.
These were very beautiful little fish, but the reality is that rainbow trout have no business in these streams. Originally, these streams were the natural habitat of the Rio Grande cutthroat trout, New Mexico’s state fish.
Rainbow trout, once originally native to streams that flowed into the Pacific Ocean, have been introduced to practically every state. There are wild populations of rainbow trout from Maine to California. At one time, the state fish of Colorado was considered to be the rainbow trout. In 1994, Colorado adopted the greenback cutthroat trout as its state fish because it was indigenous to Colorado, unlike the rainbow trout.
The spread of rainbow trout is not limited to the United States. Some of the best rainbow trout fishing in the world exists in Argentina, Chile and New Zealand. But these were fish introduced by humans.
The reason rainbow trout have spread around the world is they are the species most commonly and easily raised in trout hatcheries. Rainbow trout were the first trout species raised in hatcheries in the United States and strains were developed that were adaptable to hatchery life.
As the hatchery system grew, the strains of rainbow trout followed. Their natural beauty and fighting ability made them popular with anglers. With wild populations of native trout declining due to overfishing and habitat loss, the hatchery trout were welcomed to provide sport and food. Some of these fish, like the ones I encountered in the Rio Capulin and Rio Tusas, adapted to their new environment and began to reproduce naturally.
The introduction of rainbow trout into the streams to which they were not native has tended to have a negative effect on remaining native fish populations, including here in New Mexico. Rainbow trout bred with the native species such as cutthroat and the Gila trout of Southwestern New Mexico, creating a hybrid trout. This diluted the gene pool of the native species. Introduced rainbow trout would also prey heavily on native fish, insects and amphibians, disrupting the ecology of the streams.
The popularity of the fish, the ease with which it was raised in hatcheries and the sport it provided to anglers outweighed the negative effects, which were not totally understood in the early days of trout stocking.
In New Mexico, over two million rainbow trout were stocked in 2009, including over one million of catchable size, according to Roddy Gallegos, of the state Game and Fish Department. New Mexico currently has three federal fish hatcheries and six state fish hatcheries.
The only fish hatchery in Rio Arriba County is Los Ojos in the northern part of the County. It was formerly called the Parkview Hatchery. This hatchery has undergone an extensive change in recent years. Back in 1976, I went to the hatchery, then called Parkview, to do a college project on how a hatchery operates. At that time, the hatchery raised rainbow trout to a catchable size (about nine inches). Once they reached this size, they were released into streams, lakes and rivers.
I took pictures as female trout were stripped of their eggs, done by gently squeezing their bellies towards their tails. The eggs were then fertilized with milt from male trout, which was obtained in the same way as the eggs. The fertilized eggs were then taken inside the hatchery building, where they were hatched in long trays of cool flowing water. Naturally, trout breed where there is flowing water and the eggs need it to hatch.
Once the fish became too big to be raised inside the hatchery, they were transferred to concrete race ways outdoors, where they were fed pelletized food until they reached catchable size.
However, it was discovered the hatchery was infested with whirling disease in 1999. Whirling disease attacks the cartilage in trout’s backbones and causes them to swim in circles, hence the name. It is particularly destructive to rainbow trout. The disease is natural to Europe and it is believed to have been brought to the United States by hatchery fish from Europe. Once established in a stream, it is impossible to eradicate.
Attempts to eradicate whirling disease at the hatchery initially failed, so Los Ojos was shut down in 2003. All the trout in it were killed and the facilities thoroughly cleaned and disinfected. The spring water that Los Ojos uses has been thoroughly tested and found to be free of whirling disease, so it was believed that the contamination came from the outside by predators like ospreys and raccoons. The outdoor concrete raceways are now enclosed in an impressively large building to prevent that.
Right now, Los Ojos is raising a test batch of rainbow trout, called sentinels, to see if they remain free of whirling disease. If all goes well, it will be back on line raising trout to stock in the waters of New Mexico.
There are those who put down hatchery fish and certainly mistakes were made in the early days of fish stocking, with different species of fish being introduced all over the United States and the world without much thought or knowledge as to what the impact would be on the native species, the local ecology or whether the fish would even survive in their new environment. Trout and salmon were even stocked in the Mississippi River. They did not survive.
Recently, there has been renewed interest in reestablishing populations of indigenous species back into their native habitat. The Rio Grande cutthroat and the Gila trout are now being raised in hatcheries and reintroduced into some of their native streams. Hatcheries are providing the means to bring back these native fish.
Hatchery trout have provided anglers with countless hours of fishing fun and plenty of good meals. For me, it’s fun to catch different species of fish that without hatcheries I wouldn’t be able to fish for in New Mexico.