Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint® Lectures for Biology: Concepts and Connections, Fifth Edition – Campbell, Reece, Taylor, and Simon Essential Biology, Second Edition – Campbell, Reece, and Simon Essential Biology with Physiology – Campbell, Reece, and Simon Lectures by Chris Romero, Front Range Community College Counting the Last Fish Current Issues in Biology, Volume 1 Scientific American

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish New studies have shown that fisheries worldwide are in danger of collapsing from overfishing. However, many people still view the ocean as a limitless resource. Concept Review

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Concept Review Before 1982, the ocean fishing industry was unregulated. - In 1982, the United Nations adopted the Convention on the of the Sea, which regulated fishing to within 200 miles of a country’s shoreline.

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Concept Review Despite these regulations, populations of oceanic fish continue to drop significantly. One of the causes of the population depletions is a phenomenon called “fishing down the food web.”

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Food webs are characterized by trophic levels. - These levels “rank” how far removed an individual organism is from the primary production at the base of the food web. Concept Review

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Concept Review “Fishing down” occurs when fishers deplete large predator fish and then begin to target smaller species that would usually be eaten by the large fish.

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish This overfishing has caused the complexity of the food chains in important fisheries to drop by more than one trophic level. Concept Review

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Research has shown that industrial fishing fleets take only a few decades to reduce the biomass of a previously unfished stocked by a factor of 10. The popularity in the U.S. of fish as nutritious foods has undoubtedly contributed to the decline in their natural stocks. Concept Review

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Resolving the difficulties now besetting the world’s fisheries is complex and involves many solutions. - Ecosystem-based management - Creating no-take zones - Conservation of species Concept Review

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Which of the following statements is true concerning commercial fishing today? a) The size of hauls is decreasing. b) The sizes of fish being caught are decreasing. c) More immature fish are being caught. d) All of the above. Testing Your Comprehension

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Testing Your Comprehension Which of the following statements is true concerning commercial fishing today? d) All of the above.

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Generally speaking, how does overfishing affect food webs? a) It increases the number of connections in the web. b) It decreases the number of connections in the web. c) It decreases the number of trophic levels. d) It increases the number of trophic levels. Testing Your Comprehension

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Testing Your Comprehension Generally speaking, how does overfishing affect food webs? c) It decreases the number of trophic levels.

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Which of the following types of marine organisms have been most affected by overfishing? a) phytoplankton b) zooplankton c) small pelagic fish d) large predatory fish Testing Your Comprehension

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Testing Your Comprehension Which of the following types of marine organisms have been most affected by overfishing? d) large predatory fish

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish The Audobon Society has ranked fish by the danger they face from overfishing. Would these rankings affect your choice of fish to buy or eat? Strongly Agree Strongly Disagree A. E. C. B. D. Biology In Society

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Biology In Society Do you agree with the United Nations agreement that every maritime country should have exclusive fishing rights in the oceans within 200 miles of their shoreline? Strongly Agree Strongly Disagree A. E. C. B. D.

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish By analyzing this graph, which population has had the largest increase in annual catch? a)small pelagic fish b)large pelagic fish c)invertebrates d)groundfish Thinking About Science

Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings Counting the Last Fish Thinking About Science By analyzing this graph, which population has had the largest increase in annual catch? c)invertebrates