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La Paz County, Arizona

Information provided for informational purposes only

Note: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.

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Pesticide Table for the Desert Pupfish and the Gila (Yaqui) Topminnow
Pesticide Table for the Yuma Clapper Rail | About the Desert Pupfish | About the Gila (Yaqui) Topminnow | About the Yuma Clapper Rail
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LaPaz County, Arizona

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Desert Pupfish and the Gila (Yaqui) Topminnow

Table of Pesticide Active Ingredients

Active Ingredient Code TAR*
ALDICARB 2a  
AZINPHOS-METHYL 2a  
BENOMYL 2a  
BENSULIDE 2a  
CAPTAN 1a  
CARBARYL 3a  
CARBOFURAN 2a  
CHLOROTHALONIL 2a  
CHLORPYRIFOS   
Alfalfa
43a  
All Other Uses Except
as a Termiticide
3a  
COPPER SULFATE (all salts) 2a  
DIAZINON  
Granular Formulations and
Soil-incorporated Liquids
2a  
Liquids not Soil-incorporated
3a  
DICOFOL 2a  
DICROTOPHOS 2a  
DISULFOTON 2a  
ENDOSULFAN 2a  
ETHION 2a  
ETHOPROP 2a  
FENAMIPHOS 2a  
FONOFOS 2a  
ISOFENPHOS 2a 
MALATHION 3a. 5a  
MANCOZEB 2a  
METHIDATHION 2a  
METHOMYL 5a, 196 0.2
METHYL PARATHION 3a, 5a  
NALED 5a, 396 2.0
OXAMYL 2a  
OXYDEMETON-METHYL 2a  
OXYFLUORFEN 2a  
PARATHION (ethyl) 2a  
PENDIMETHALIN 2a  
PHORATE 2a  
PHOSMET 2a  
PROFENOFOS 2a  
PROPACHLOR (granular) 296 1.3
PROPACHLOR (non-granular) 396 0.4
PROPARGITE 2a  
PYRETHRINS 1a, 5a  
SULPROFOS 2a  
TERBUFOS 2a  
THIODICARB 2a  
THIOPHANATE-METHYL 2a  
TRIBUFOS (DEF) 2a  
TRICHLORFON (granular) 2a  
TRICHLORFON (non-granular) 396 3.5
TRIFLURALIN 2a  

* TAR = Threshold Application Rate (Pounds of active ingredient per acre per applications)
Code Limitations
1a Within the area described under the Shading Key, do not apply this pesticide within 20 yards from the edge of water for ground applications, nor within 100 yards for aerial applications.
2a Within the area described under the Shading Key, do not apply this pesticide within 40 yards from the edge of water for ground applications, nor within 200 yards for aerial applications.
3a Within the area described under the Shading Key, do not apply this pesticide within 100 yards from the edge of water for ground applications, nor within 1/4 mile for aerial applications.
5a Do not apply ultra low volume (ULV) applications within 1 mile from the edge of water within the area described under the Shading Key.
43a Within the area described under the Shading Key, do not apply this pesticide within 100 yards from the edge of water for ground applications, nor within 1/4 mile for aerial applications.
196 Within the area described under the Shading Key, do not apply this pesticide above the threshold application rate (TAR) indicated within 20 yards from the edge of water for ground applications, nor within 100 yards for aerial applications.
296 Within the area described under the Shading Key, do not apply this pesticide above the threshold application rate (TAR) indicated within 40 yards from the edge of water for ground applications, nor within 200 yards for aerial applications.
396 Within the area described under the Shading Key, do not apply this pesticide above the threshold application rate (TAR) indicated within 100 yards from the edge of water for ground applications, nor within 1/4 mile for aerial applications.

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Yuma Clapper Rail

Table of Pesticide Active Ingredients

Active Ingredient Code
METHYL PARATHION 20c
TEMEPHOS 20c
Code Limitations
20c Do not apply directly to water within the species habitat (described under the Shading Key).

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Desert pupfish [Cyprinodon macularius]

The Desert pupfish is a tiny, skinny fish with a smoothly rounded body. The male rarely grows larger than 7.5 centimeters (3 in). Like many other fishes in the family Cyprinodontidae, males don bright breeding colors during the mating season to attract females. With the Desert pupfish, the males turn bright blue on the head and sides, and yellow on the tail. Females and juveniles usually have tan to olive backs and silvery sides. The narrow, vertical, dark bars on the sides of adults are often interrupted and give the curious impression of a disjunct, lateral band along the fish.

In its life of about one year, the Desert pupfish matures rapidly and propagates often, producing up to three generations during its short existence. Spawning occurs throughout the spring and summer months. Females lay their eggs on submerged plants in shallow water, and males will defend the eggs up to three days until they hatch. Within hours of birth, the young begin to feed themselves on small plants and insects.

The Desert pupfish is adapted to live in the extreme climate of a harsh desert environment. This species is capable of living in water with temperatures in excess of 43 degrees C (110 F). This fish was first described in 1853 when it was collected in the San Pedro River of Arizona. It has recently been divided into two named subspecies, with possibly a third, undescribed subpecies in Mexico. It was once common in many of the desert springs, marshes, and tributary streams of Arizona, California, and Mexico. Today, the Colorado River subspecies, C. macularius macularius, is found in several Salton Sea tributaries in California, as well as associated shoreline pools and irrigation drains. In Arizona, the subspecies C. macularius eremus lives in the Quitobaquito Spring within the Organ Pipe Cactus National Monument. The species is also thought to inhabit adjacent waters in Mexico.

The largest impacts on the Desert pupfish were the groundwater pumping and the construction of dams on the Gila, Colorado, and Salt Rivers. The dams block the water flow to the lower areas of the rivers, eliminating many of the marshy pools in which the pupfish breeds. As a result, the fish are forced into mainstream channels, where they are quickly preyed upon by larger predators, many of which are fish species introduced for recreational purposes. Although it is a resilient and hardy species in many respects, the tiny Desert pupfish is unable to adequately compete and defend itself in foreign waters populated by non-native fish.

Currently, with the irrevocable loss of so much suitable habitat, the Desert pupfish is being bred in captivity for the purpose of reintroduction into the environment. At the present time, it is unclear how successful the reintroduction programs have been. However, it is clear that there are many human obstacles which will continue to make the survival of the Desert pupfish difficult.

Matthews, J.R. (ed.). 1990. The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 825-826.

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Gila and Yaqui topminnow [Poeciliopsis occidentalis]

The Gila topminnow consists of two subspecies, the Gila (Poeciliopsis occidentalis occidentalis) and the Yaqui (P. occidentalis sonoriensis), both of which are federally listed as endangered. This topminow is included in the same family as the domesticated aquarium guppy, and is similar to the guppy in many aspects. This tiny fish averages 3 to 4 centimeters (1.2 to 1.6 in) in length. It is tan to olive on the upper portions of its body and white below. Similar to other fish, the body colors of breeding males will become more vibrant in order to entice the females. Breeding male topminnows darken to jet black and develop bright yellow fins and golden tints along their midsections.

Although the lifespan of the Gila topminnow is only about one year, the species is a prolific breeder. Gestation varies from 24 to 28 days for the Gila topminnow and 12 to 14 days for the Yaqui subspecies. Unlike most other fish, the topminnow gives birth to live young, as opposed to laying eggs. The onset of breeding is affected by water temperature, daylight, and food availability.

Topminnows are able to exist in a broad range of habitats. Though they prefer shallow, warm, and fairly quiet waters, these fish are also found in moderate currents and depths up to 1 meter (3.3 ft). They make their homes in permanent and intermittent streams, marshes, and river banks, where they seek dense mats of algae and debris with sandy substrates for their preferred living environment.

Historically, this topminnow was abundant throughout the Gila River system and Rio Yaqui drainage in Arizona, New Mexico, and northern Sonora and Chihuahua, Mexico. The current severe reductions of population and suitable habitat are reasons for grave concern for the survival of the this species. The Gila Topminnow still occurs in natural populations at only eight isolated locations in the Santa Cruz River System. It is believed that extensive groundwater pumping and diversion of water for the irrigation of agriculture in Mexico have annihilated the species from that country. The Yaqui topminnow is found only at eight US locations within the Yaqui River headwaters, but is more abundant in Mexico.

Water projects such as dam building and crop irrigation transformed all free-flowing southwestern rivers into intermittent, deeply cut streams or broad, sandy washes, reducing the topminnow populations to a fraction of their pre-1860's range. As with other species of fish found in Arizona, the topminnow is also threatened by aggressive and predatory, non-native fish which have been introduced for recreational purposes. Other introduced species like the related mosquitofish harass adult topminnows and feed on the young, and are a major obstacle to the continuing survival of these fish. Only when a habitat is sufficiently large can these two species coexist.

Some of the topminnow populations are found on National Wildlife Refuges and are well protected. The species is also successfully reared in captivity and has been reintroduced into the wild. However, even with the gifted fertility of this fish, it is clear that the Gila and Yaqui topminnows need large, stable habitats to ensure their survival.

Matthews, J.R. (ed.). 1990. The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 928-929.

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Yuma clapper rail [Rallus longirostris yumanensis]

The Yuma clapper rail is one of seven North American subspecies of the clapper rail, a henlike marsh bird. The Yuma subspecies is graybrown with a tawny breast, a white throat and undertail, and bars across its flanks. The Yuma clapper rail is a large bird, measuring 36 to 42 centimeters (14 to 16 in) in length.

Clapper rails feed on crayfish, small fish, clams, isopods, and a variety of insects. The birds remain on their US breeding grounds from mid-April to mid-September, when they migrate south to Mexico for the winter. The Yuma clapper cail is a mysterious creature in its breeding and nesting practices. It is thought that the bird lays about six eggs. They construct their various types of nests on dry hammocks or in small shrubs amid dense cattails, just above water level.

In the United States, the Yuma clapper rail seeks out nesting sites among tall cattails and bulrushes along the margins of shallow, stable ponds of freshwater marshes. Western clapper rails range from northern California to central Mexico. It is possible that the Yuma subspecies did not exist in the US along the lower Colorado River area until larger marshes were formed following dam construction. Today, the estimated 1,700-2,000 birds occur in the freshwater marshes along the lower Gila River, the Salton Sea, and along the Colorado River from Needles, CA southward.

Water control projects on the Colorado River have built dams which altered the nature of this free-flowing body of water. Some backwaters were eliminated, but the dams created much new habitat for the birds by allowing sedimentation, which in turn allowed cattail and bulrush marshes to emerge. However, other suitable rail habitat has been lost through dredging and channelization projects along the Colorado River. In addition, the Salton Sea, while providing a significant amount of habitat, is becoming very salty. Regular outbreaks of botulism there have killed numerous birds, including rails.

Although the rail population appears stable, there is no denial that its fate is directly related to the various water projects along the Colorado River. It is clear that the key to preserving the Yuma clapper rail is the maintenance of early growth stages of cattail marsh by creating shallow water areas. The mats of dead cattails in the shallows will eventually provide nesting cover for the rails.

Matthews, J.R. (ed.). 1990. The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 690-691.

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