Colorado Pikeminnow

Click for a larger view. Image courtesy US FWS, J.E. Johnson, Photographer

Colorado Pikeminnow
Ptychocheilus lucius
Image courtesy US FWS,
J.E. Johnson, Photographer

One of the largest minnows in the world, the Colorado pikeminnow was once found throughout the Colorado River basin. This is no bait minnow. Also known as the Colorado squawfish, it reputedly grew to a whopping 6 feet in length with a weight topping 80 pounds and a life span of 40 years. The largest caught in recent times have been only 3 feet long and 9 pounds.

Colorado pikeminnows once flourished throughout the Colorado River and most of its major tributaries. Historically, these abundant, torpedo-shaped fish were prized for their fine flavor. They were an important food fish for Native Americans and welcomed at restaurants as far away as San Francisco. Also called white salmon by early settlers due to their migratory behavior, pikeminnows journeyed 200 miles to spawn in turbid backwaters.

Then we built dams which blocked the migratory runs of pikeminnows. Below the Grand Canyon, the last wild Colorado pikeminnow was caught in 1976. The proliferation of dams has drastically restricted their range. Moreover, reservoirs flood what was suitable river habitat, and their dams alter river flows and water temperature downstream.

The Colorado pikeminnow was one of the first fish given full protection under the Endangered Species Act in 1973. Today, there are two remaining wild populations. One resides in the upper reaches of the Colorado river system, the other in the Green River system. Efforts underway to restock Colorado pikeminnow in the San Juan River basin appear to be successful.

A broadly based coalition of partners established the Upper Colorado River Endangered Fish Recovery Program in 1988. This program focuses on 4 species of fish: humpback chub, bonytail, Colorado pikeminnow and razorback sucker. Their goal is to restore and manage stream flows and habitat, reduce competition from some non-native fish species and increase populations using hatchery raised young. If they are successful, this giant piscine predator will once again take its rightful place in the upper Colorado River ecosystem.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Photos: Courtesy US FWS, images.fws.gov
Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

wikipedia.org/wiki/Colorado_pikeminnow
http://www.fws.gov/mountain-prairie/pressrel/10-84.htm
http://www.coloradoriverrecovery.org/general-information/the-fish/colorado-pikeminnow.html
http://ndow.org/wild/animals/facts/fish_colorado_pike_minnow.shtm
http://dwrcdc.nr.utah.gov/rsgis2/search/Display.asp?FlNm=ptycluci
http://wildlife.state.co.us/Fishing/SpeciesID/Pages/FishID.aspx
http://wildlife.utah.gov/fishing/nonnative/endangeredfishfacts.pdf

Antlions and Tiger Beetles

Ant Lion pit
showing loose sides that slide victims
to awaiting jaws at the bottom

Courtesy & Copyright,
Jim Cane, Photographer

Courtesy Wikimedia
Licensed under
GNU Free Documentation License

Lions and tigers in Utah. Oh my! But fear not unless you are an insect. Ant lions and tiger beetles are fierce, diminutive predators. They are not related to each other and the adults look very different, but the larval stages behave in very similar ways. Both await their prey in earthen lairs.

The conical pits of antlions are found in dry, soft sand, frequently under trees, rock overhangs or house eaves. The larvae dig their pit by crawling backwards in a spiral, plowing with their abdomen. The slope of the sides reaches the angle of repose, which is the steepest angle that the sand can lie before it collapses from a slight disturbance. They embed themselves in the sand at the bottom of the pit with their enormous mandibles open like a bear trap. Any small insect that inadvertently steps over the edge of the pit will tumble to the bottom into waiting jaws.

Tiger beetle larvae also await their prey in a burrow, but theirs is a narrow cylinder. The adult female inserts her eggs in the soil. The young larva uses its formidable mandibles to loosen the surrounding dirt, pushing it to the surface with its head and thorax. The larva’s lower back has a prominent hump with two pairs of large hooks. With these, it anchors itself to the burrow wall, its mandibles poised at soil level. Woe to the insect that walks nearby.

The adults of these two underground predators differ in both appearance and lifestyle. The adult antlion resembles a damsel fly with two pairs of long, transparent wings and a weak, nocturnal flight. The adult does not feed and only lives about 3 weeks. Conversely, the diurnal adult tiger beetle is an aggressive, mobile predator. For its size, it is the fastest running insect. It runs so quickly that it cannot see its prey, so sprints and stops repeatedly to track its intended victim. Tiger beetles come in diverse colors and patterns including bright, iridescent greens and blues. In Utah, look for them on bare ground, such as trails in open country or on dunes.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Images: Courtesy and Copyright Jim Cane
            And Courtesy Wikimedia

Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Tiger Beetles:


http://askabiologist.asu.edu/explore/chasing-tiny-tigers

A field guide to the tiger beetles of the United States and Canada [electronic resource] : identification, natural history, and distribution of the Cicindelidae / David L. Pearson, C. Barry Knisley, and Charles J. Kazilek New York : Oxford University Press, 2005. (via Amazon) https://www.amazon.com/Field-Beetles-United-States-Canada/dp/0199367175/

http://en.wikipedia.org/wiki/Tiger_beetle

Antlions:

http://bugguide.net/node/view/137

https://www2.palomar.edu/users/warmstrong/pljuly97.htm

Scuds

Scud
Amphipod – Gammaridae
Courtesy US EPA

Scud
Great Lakes Amphipod
Courtesy USGS
David M. Knott, Photographer

Tiny scuds abound in Utah’s waters, their flattened, flea-like bodies allowing them to scramble and tumble giddily under the surface. These crustaceans in the order Amphipoda can be up to ½ inch in length. Also known as freshwater shrimp and side swimmers , scuds look like minuscule, flattened shrimp with orderly ranks of leg-like appendages. Some of these legs can grip and are used for climbing and to anchor in the water. The front 2 pairs have tiny flaps to clasp their food while dining. The middle legs are for swimming. The hindmost legs can be used to kick off against surfaces propelling the scud forward.

All this exuberant movement helps scuds dodge predators and provides them with their common name. To scud under sail is to move swiftly before a gale. The blowing foam at the crest of waves is called scud. Evasive acrobatics are vital since scuds are a favored food of many fish. Half of a trout’s annual diet can consist of scuds. No wonder anglers use lures that mimic them.

Scuds coloration matches their habitat with browns and greens most common. When newly molted they are semi-transparent and baby blue. The female has a brood sac called a marsupium where she holds her eggs for fertilization and incubation. Fertilized eggs are usually bright orange. The newly hatched young are tiny versions of their parents.

In Utah, look for scuds in still water and in the calmer water along edges of streams and rivers. Prime habitat offers an abundance of submergent vegetation for concealment and plenty of plant and animal debris on which to scavenge. Our alkaline waters are rich in dissolved calcium carbonate which scuds incorporate into their chitinous exoskeleton.

To get a good look at these fascinating acrobats, catch them with a simple aquarium net and place them in a pan of water with some vegetation.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Graphics: Courtesy US EPA and USGS
Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

http://www.epa.gov/bioiweb1/html/amphipods.html

http://www.pond-life.us/pond-life-crustaceans-1.html

http://www.troutnut.com/hatch/71/Arthropod-Amphipoda-Scuds

http://www.flyfishersrepublic.com/entomology/crustaceans/freshwater-shrimp/

A Guide to Common Freshwater Invertebrates of North America by J. Reese Voshell Jr. http://www.amazon.com/Guide-Common-Freshwater-Invertebrates-America/dp/0939923874

Field Guide to Freshwater Invertebrates of North America by James H. Thorp http://www.amazon.com/Field-Freshwater-Invertebrates-America-Academic/dp/012381426X

Guide to Aquatic Insects & Crustaceans by Izaak Walton League of America http://www.amazon.com/Aquatic-Insects-Crustaceans-Walton-America/dp/0811732452

Seed Dispersal

Maple Seeds
Courtesy & Copyright © 2011
Linda Kervin

Milkweed Seeds
Courtesy & Copyright © 2011
Jim Cane

Burdock Flower
Courtesy & Copyright 2009 Jim Cane

Burdock Hooks
Courtesy & Copyright 2009 Jim Cane

Autumn is a season of travelers. Birds migrate south. Deer, elk and antelope move to their wintering grounds. Many plants finish maturing seeds designed for transport to favorable new habitats. Seeds come in a kaleidoscope of shapes and sizes: their structure reveals their means of dispersal.

Many plants rely on the wind to loft their seed to fertile ground. Due to wind’s fickle nature, few of these seeds actually make it to a suitable site, so to compensate they are produced in abundance. Some seeds, like those of dandelion and milkweed, have a downy fluff which floats aloft with the slightest breeze. Others utilize wing-like appendages on the seed capsule, as in maple, ash and pines. The seed is heavier than the blade shaped wing, causing a spiraling motion which propels seeds farther than mere drifting.

Another strategy for seed dispersal is to entice animals to ingest the seed. Some plants like cherries, junipers and grapes do this by imbedding their seeds in a nutritious and tasty pulp. Others, like many grasses, achieve the same end by the placement of the seeds. As grazers consume the foliage, they inadvertently ingest seeds at the same time. Hopefully the seeds end up some distance from the parent plant, deposited in their own dollop of manure to aid seedling growth. Some seeds require a trip through the digestive tract, where the impervious seed coat is eroded away so that the seed can absorb water and germinate. Ants disperse seeds that have a patch of nutritious tissue, the aril, that they gnaw off before discarding the seed.

Another means of dispersal relies on a chance encounter to hitch a ride in an animal’s fur. The seed coat has clinging hooks, hairs or spines that latch onto fur or clothing. Many noxious weeds including burdock, hound’s tongue and cheatgrass use this type of dispersal, so be careful where you groom and dispose of their seed.

Grasses don’t run and pines don’t roam, but plant seeds have many tricks to gain mobility.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Images: Courtesy & Copyright Jim Cane &
            Courtesy & Copyright Linda Kervin
Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Seed Dispersal
http://andromeda.cavehill.uwi.edu/Dispersal.htm

Wind Dispersal
https://www2.palomar.edu/users/warmstrong/plfeb99.htm

Seed Dispersal by Animals
http://www.cnr.uidaho.edu/range556/…