Fish

 

Note

Fishing is allowed, with a current Utah State fishing license required for everyone 12 or older. However, it is a far more successful recreational activity at the multiple nearby reservoirs instead of within the national park. [There are no documented reports of people becoming sick after eating fish caught during a cyanobacteria bloom. The toxins caused by the bacteria are known to build up in the tissues of fish.]

 

Flannelmouth Sucker (Catostomus latipinnis)

Zion National Park Photo

 

The Virgin River Habitat

Flowing through Zion National Park are the North and East forks of the Virgin River and their various tributaries. These streams are all part of the Virgin River drainage, which is part of the larger Colorado River Basin. There are six fish species native to the Virgin River Basin, four of which reach the headwaters where Zion is located. Three of the six species are found widely in the Colorado River system, and three are found only in the Virgin River.

The rivers of Zion National Park retain their full complement of four species of native fish in healthy populations. Such a statement cannot be made for any other comparable river system in the southwest U.S. This rare and desirable condition is only possible because stream flow in the park is essentially natural, with all of the floods, sediment transport and periods of low flow that have always occurred.

The fish of the Virgin River drainage have evolved adaptations to the unique local conditions, including heavy silt loads, frequent floods, and wide fluctuations in water temperature and discharge.

Unfortunately, outside of the park the native fish of the Virgin River have experienced population declines due to habitat fragmentation and the introduction of non-native species. Efforts are currently underway to protect rivers that provide good habitat, and restore areas of lost or degraded habitat to provide for the recovery and protection of the native fish.

 

Native Fish of Zion

There are four species of native fish found in the Virgin River and its tributaries within Zion National Park’s boundaries. Identifying these species can be accomplished through observing characteristics such as size, color, geographic and spatial location in the river, feeding behavior, and eye or mouth shape and placement.

The native fish are able to live in this harsh environment with the right adaptations. They all share dark coloring on top and light coloring below, more likely to blend in with sediment-laden waters. Their torpedo-shaped bodies and large fins allow them to move more quickly through faster waters. They exhibit benthic behaviors, spending time on the river bottom—especially the suckers. The suckers may also be larger, but they are thermally labile, able to handle great changes in water temperature. All four native fish generally breed when the river is higher from winter and spring snowmelt, but before summer monsoon rains can commonly create flash floods. The native fish populations will decline after flash flood events, but their numbers do not suffer to the extent that invasive fish populations do. The populations of all four species are all currently understood to be healthy.

 

Virgin River Spinedace (Lepidomeda mollispinis) 

Zion National Park Photo

Virgin River Spinedace

(Lepidomeda mollispinis)

Description: 4-6 inches long with a shiny silver body. 3 year lifespan. Within Zion, they are found in the North Fork and East Fork of the Virgin River.

Diet: Opportunistic omnivore, but primarily insectivorous.

Fun Fact: Named for the Virgin River running through Zion National Park and the Narrows, these Spinedace are endemic to the Virgin River drainage.

 

Speckled Dace (Rhinichthys osculus)

NPS Photo

Speckled Dace

(Rhinichthys osculus)

Description: 2-3 inches long, olive/yellow side and back with dark flecks. 3 year lifespan. Located in all of Zion’s waters with some fish.

Diet: Feeds on mostly insects, some plant material and zooplankton.

Fun Fact: Both the lower Colorado River and Sevier River genotypes of Speckled Dace are present in Zion National Park. This indicates that both watersheds crossed through this area at some point in the past.

 

Desert Sucker (Catostomus clarkia) 

Zion National Park Photo

Desert Sucker

(Catostomus clarkia)

Description: 8-15 inches long with brown/green backs transitioning to silver/tan/yellow stomachs. Large variation in coloring. 8-10 year lifespan. Found in all of Zion’s waters with some fish.

Diet: Feed on diatoms and algae (including any animal material in the algae).

Fun Fact: Desert Suckers utilize a hard, protruding ridge in their lower lip made of cartilage to scrape rocks along the stream bed for algae.

 

Flannelmouth Sucker (Catostomus latipinnis) 

Zion National Park Photo

Flannelmouth Sucker

(Catostomus latipinnis)

Description: 12-25 inches long. Dark brown/green back, yellow/orange side, and white underside. 10 year lifespan. Located in the North Fork, East Fork, and North Creek in Zion National Park.

Diet: Mostly eat algae, as well as some invertebrates and plant material.

Fun Fact: Flannelmouth Suckers also feed on algae like Desert suckers, but instead have a fleshy lower lip that is split into two lobes down the middle. Their lips extend out and have taste buds on the surface to help find food.

 

Non-Native Fish of Zion

There are five documented invasive species, with the most common being Rainbow Trout. Other rare invasive fish include Bonneville Cutthroat, Brook, and Brown Trout, as well as Channel Catfish. None of these invasives can survive in high numbers because they are not adapted to the Virgin River with its steep grade, high sediment load, and flash floods.

Zion (all present in low numbers):

Rainbow Trout - Oncorhynchus mykiss
Cutthroat Trout - Oncorhynchus clarki
Brown Trout - Salmo trutta
Channel Catfish - Ictalurus punctatus
Brook Trout - Salvelinus fontinalis

 

Virgin River Program Fish Monitoring, 2012

Zion National Park Photo

Conservation Efforts

Zion National Park works in conjunction with the Virgin River Program. The Virgin River Program is a large cooperative with National Park Service, Utah Department of Natural Resources, U.S. Fish and Wildlife Service including others. The program helps Zion to monitor fish species within the park's waterways, controlling non-native fish populations, and assisting in watershed planning measures.

Despite their resilience in Zion, not all of our native fish are doing well elsewhere. The Virgin River Spinedace and the Flannelmouth Sucker are both managed under conservation agreements as their populations are declining across their native habitat. But the Virgin River above Zion National Park has not been dammed, and still experiences natural patterns of water flow and sedimentation. The other areas where these fish are found have been unnaturally altered, and the native fish are suffering for it. Zion is an important haven to these fish that are key examples of survival and preservation.