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Resources by Louis A. Helfrich

Title Available As Summary Date ID Author
Sustaining America's Aquatic Biodiversity - What Is Aquatic Biodiversity; Why Is it Important?
Aquatic biodiversity is the rich and wonderful variety of plants and animals—from crayfish to catfish, from mussels to mayflies, from tadpoles to trout—that live in watery habitats. It is the number of different native species, or species richness.
Dec 18, 2019 420-520 (CNRE-77P)
Sustaining America's Aquatic Biodiversity - Why Is Aquatic Biodiversity Declining?
When a species goes extinct, all the genetic information carried by individuals of that species is lost forever, never to be reproduced again. Extinction is a terrible waste of life and a loss of potential solutions to future problems such as possible cures to disease and solutions for survival in a changing world.
Jan 7, 2020 420-521 (CNRE-78P)
Sustaining America's Aquatic Biodiversity - Aquatic Habitats: Homes for Aquatic Animals
Natural aquatic habitats include ponds, lakes, rivers, streams, springs, estuaries, bays, and various types of wetlands. Some of these habitats are shallow and others deep, some are cold-water and others warm-water, some are freshwater and others saltwater, and some have high oxygen levels and others little oxygen.
Feb 11, 2020 420-522 (CNRE-79P)
Sustaining America's Aquatic Biodiversity - Freshwater Mussel Biodiversity and Conservation
Nearly 300 species of mussels inhabit freshwater rivers, streams, and lakes in the United States. This is the richest diversity of mussels found in the world and an extraordinary natural heritage that needs protection. Because of the lustrous, pearl-like interior of the shells, some of these pearly mussels have important commercial value in the cultured pearl and jewelry industry.
Jan 7, 2020 420-523 (CNRE-80P)
Sustaining America's Aquatic Biodiversity - Crayfish Biodiversity and Conservation
Of the approximately 500 crayfishes (some times called crawdads or crawfish) found on earth, about 400 crayfish species live in waters in North America, and about 353, nearly 70 percent of the world’s total species, inhabit waters in the United States.
Mar 24, 2020 420-524 (CNRE-82P)
Sustaining America's Aquatic Biodiversity - Freshwater Fish Biodiversity and Conservation
Nearly 800 native fish species in 36 families inhabit the freshwater rivers, streams, and lakes of the United States and Canada. North America has the most diverse temperate freshwater fish fauna in the world.
Feb 11, 2020 420-525 (CNRE-83P)
Sustaining America's Aquatic Biodiversity - Selected Freshwater Fish Families
This is the largest and most ecologically diverse family of freshwater fishes in the world. Minnows are exclusively freshwater, although some species stray into brackish, tidal waters. Over 290 species of minnows occur in North America.
Feb 12, 2020 420-526 (CNRE-90P)
Understanding Fish Nutrition, Feeds, and Feeding Jul 5, 2017 420-256 (FST-269P)