Weve been learning a lot about these chubs. In the last few years, all the fish gave the river from the Fish & & Wildlife Service fish hatchery in Dexter, NM have actually been pit-tagged. This implies they all have little social security numbers buried in their bellies.
Now when we catch fish that arent using their government-authorized pit tag number, they get tagged too. From checking out the pit tags and taking a look at the data, we know that chubs go up and down the Mimbres River Valley way more than fish biologists believed possible.
This is especially impressive given that the Mimbres River is consistently and totally diverted out of the river channel into irrigation ditches throughout the 20-mile-long valley, leaving various long, dry reach reaches. We likewise understand they are reproducing really well: small untagged fish are frequently caught.
The other thing we understand from the previous five years is that the habitat work seems to have truly assisted chub: weve been catching more fish of all sizes these past years. Of course theres the caveat that its a little sample size, simply a few years, and not statistically significant. However, weve celebrated all the fish weve caught, happy when we see the population trend line going upward.
One member of this falls sampling team, a New Mexico State University trainee Giulio Del Piccolo, will be looking for chub up and down the river for his masters thesis, doing an old-fashioned life history research study of the sort that is ending up being less fashionable to fund, however remains one of the most enjoyable sort of science to do.
He will also be developing a population design– which will likely be less enjoyable but will likely assist us understand population dynamics of the chub and increase his task skills.
A Chihuahua chub. © Brian Gratwicke/ Flickr
Where are the Fish?
So why did we capture so couple of fish this year? Its entirely possible that because we sampled later on in the season, we captured less fish, stated biologist Bryan Ferguson with NMDGF. During the regular monthly surveys, the variety of fish captured monthly of the year was highly variable.
In addition, the habitat in the repaired fall monitoring stretch isnt that excellent compared to what is up and downstream after the $2 million improvements.
I discovered this news soothing. Funny to discover some convenience in science, in data. I also relieved my distress with a dose of hope, likewise supported by proof and history: these are scrappy fish, enduring fire and flood and dry spell. Well be back next year.
Martha S. Cooper is the Southwest New Mexico and Freshwater Program Manager for The Nature Conservancy.
This is the story of the Chihuahua chub (Gila nigrescens). It was believed extinct, last seen in 1851, till a local school teacher, working for the New Mexico Department of Game and Fish (NMDGF) during the summertime, caught one in 1975. I fulfilled this gentleman a couple of years back at a regional nature conference. In my mind he was a legend; I should have asked him for his sign. He was simply a regular down-to-earth older guy, still curious about the natural word.
These chubs? Not regular. They are a Federally-listed threatened species and endemic to the Guzman Basin that stretches from southwest New Mexico not Chihuahua Mexico. The fish is treated as threatened by the State of New Mexico. The chubs best and only remaining environment is found in the 15 mile-long Mimbres River in Southwest New Mexico. The Mimbres Valley is also house to The Nature Conservancys Mimbres River Preserve, which I steward.
Fish Survey
I work hard to integrate a bit of outdoor enjoyable into my desk job, so recently I discovered myself out with the NMDGF crew surveying fish in the Mimbres River. This takes place every fall, sweeping the river by electro-shocking and seining, gathering fish to measure and weight, and keeping in mind the incidental endangered Chiricahua leopard frog.
Signing up with these annual surveys is a quite great way to meet fish, to take them up deftly with dip internet, to transfer them in containers, to determine and sit and weigh them, to photo golden, shimmery, pale- pink large chub. A bit about the color: NMGDF describes them as “dusky brown to brassy green on white and top on the tummy.” While I just dont see the green, I agree that their tender stubborn bellies are white.
Chub habitat on the Mimbres River of New Mexico. © Martha S. Cooper/ TNC
We also tape other fish we capture. The other fish we caught is longfin dace (Agosia chrysogaster), which I think of as the robin of the fish neighborhood: common and prevalent in the Gila and Mimbres watersheds.
This fall, sampling happened a couple of weeks later on in October than usual. The day was still golden warm, a still, sweet, sun-warmed NM day with a big blue sky. We had an abnormally large sampling team this year, so I thought tasting would go relatively quickly. It didnt, due to the fact that we kept having equipment failures (the really costly surprise is all set to retire or get fixed). With functional devices, we would have been carried out in record time: we caught barely any fish this year. Inexplicably. And maybe cause for distress.
However prior to going crazy, imagining that something devastating has actually happened to the chub, its practical to take the viewpoint, to think about the context, to look at the trajectory of this population in the Mimbres River over time.
Rio Grande sucker. © Martha S. Cooper/ TNC
A Future for Chubs
Every year, I enjoy to reveal up for these tasting days, taking photographs of actually big chub took out of deep undercut banks, and quietly feeling happy that The Nature Conservancy has such wonderful chub habitat. That didnt occur this year: no big fish, few little fish, no gloating over our fantastic habitat.
In 2017 NM Game and fish worked truly tough to improve chub environment, investing $1M on their residential or commercial property and $1M on our Mimbres Preserve to make pools and bury logs in the bank, increasing the deep holes in undercut banks, favored environment for chub. Part of this task involved capturing and moving as many fish as possible from the reach where heavy devices would be working. It also implied surveying them when a month for several months in a row as part of a monitoring requirement.
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Signing up with these annual surveys is a quite great way to fulfill fish, to nab them up deftly with dip nets, to transfer them in pails, to sit and determine and weigh them, to picture golden, shimmery, pale- pink big chub. The other fish we caught is longfin dace (Agosia chrysogaster), which I think of as the robin of the fish community: prevalent and typical in the Gila and Mimbres watersheds. In 2017 NM Game and fish worked actually tough to enhance chub habitat, investing $1M on their property and $1M on our Mimbres Preserve to make pools and bury logs in the bank, increasing the deep holes in undercut banks, preferred habitat for chub. The other thing we understand from the past five years is that the environment work appears to have actually helped chub: weve been capturing more fish of all sizes these past years. Throughout the month-to-month surveys, the number of fish captured each month of the year was highly variable.