1Productivity per unit area (m2)Total Productivity (global)Chapter 25 Conservation• Important concepts: Biodiversity and Fishery Stocks.• Looked at lot of diversity in class – what is happening to it and why?• Biodiversity – variety of live forms and processesChapter 25 Conservation• Extinction in fishes – IUCN 596 Fish species listed as imperiled; 24 extinct but many more really• Estimated NA - 40 taxa extinct, 365 need special protection• 20% of ALL FISH expected to go extinct in next 25-50 years• Extinction rates increasing dramatically last 50 years –1000x average and 10-100 > mass extinctions• Normal extinction rates of animals = 9%/million years (1 or 2 per year) – Humans have accelerated these greatly • Of 9000 species freshwater about 1800 (20%) extinct or serious decline – marine not as threatened as freshwater2IUCN Red Listed SpeciesChapter 25 Conservation• Status of marine and freshwater fish faunas• Freshwater – vast majority of threatened and endangered fish live in freshwater - e.g. –freshwater as islands or as ribbons of water• Pollution – point source, sediment, run-off etc.• Water diversion – water taken for human useChapter 25 Conservation• Estuaries and inland seas– resilient species but sites of major coastal cities, freshwater diverted, ballast water (introduced species) – BUT few estuary species are endangered in spite of highly altered ecosystems. High levels of toxicity in fish• Inland Seas– Caspian and Black Seas – among most endangered ecosystems in world.3Chapter 25 Conservation• Marine – Few endangered marine species but changing rapidly – technology and fishing • Also – continental shelves – fish concentrated and human influences spreading• Coral reefs – high diversity; fishing, dynamite, poison, coral mining, sediments and pollution etc • By catch harvest • Fishing down marine trophic food webs – in ScienceChapter 25 Conservation• Characteristics of regions with most endangered fishes• Highly developed countries• Small isolated bodies of water• High endemism• Arid or Mediterranean climates• Big rivers• Big lakes• SW United States – Colorado dammed and diverted – what is left has salts and pollutants (including exotic species) Chapter 25 Conservation• Causes:• 1) Habitat Loss and Modification– Modification of bottom type – dredging, log removal, coral or gravel mining– Channelization and Dam building – flow, movement and sediment– Watershed perturbation – temperature, siltation– Competition for water4Chapter 25 Conservation• Causes:• 2) Species Introductions• Introduction – range extension based on human action; Transplant within country of origin; Exotic into new country• Introduction of nonnative species – want to improve fishery BUT often opposite effect is trueChapter 25 Conservation• Causes:• 2) Species Introductions (consequences)• Predators - Nile Perch, Peacock cichlid, Lamprey in Great Lakes• Competition - Tilapia inhibit largemouth bass, Oreochromis niloticusin Lake Victoria • Hybridization and introgression (hybrid offspring w/ parental genotypes) - Pupfish, Chubs and Tilapia • Parasites and diseases (bacterial and virsus = Furunculosis (trout bacteria) – Whirling disease (protozoan – immune in Europe; effects NA), ICH, Asian tapeworm• Ballast water introductions – ruffe, round goby, zebra muscles5Chapter 25 Conservation• Causes:• 3) Pollution - chemical, nutrient and sediment –Acid rain– Agricultural chemicals– Heavy metals – Indicators of Environmental Health – “Quality of fishing reflects the quality of living” American Sportfishing Association– Linkages between aquatic and terrestrial ecosystemsChapter 25 Conservation• Causes:• 4) Commercial Exploitation• Overfishing – About 40% commercial marine fishes exploited at unsustainable levels. “Commercial extinction” and genotypic and phenotypic changes– Pacific sardine, Peruvian anchovetas, Giant totoaba, Tuna, sharks, swordfish, Orange roughy, etc.– Cod, Haddock, flounder off Georges Bank – closed w/ hopes of recovery– Caspian Sea – 3 spp sturgeon and species flock of shadChapter 25 Conservation• Causes:• 4) Commercial Exploitation• By-catch – reduce stocks (Red Snapper, Spanish mackeral, etc.) – 1:1 to 3:1 Fish shrimp – can be 130:1 – New paper – Alaska lowest, shrimp worst 4:1• Aquarium fishes - cyanide6Chapter 25 Conservation• Causes:• 5) Global Climate Change - weather and temperatureChapter 25 Conservation• What Can Be Done?– Level at which effort addressed– Biological Preserves– Restoration– Captive Breeding– Education Chapter 25 Conservation• Conservation Biology as a new approach in fish conservation• 4) Values and fish conservation• Economic values• Ecosystem values• Existence values• Intergenerational values• Non-economic