Transcript PowerPoint
Project: fish Futures “Only 50 years left” for sea fish By Richard Black Environment correspondent, BBC News website There will be virtually nothing left to fish from the seas by the middle of the century if current trends continue, according to a major scientific study. Freshwater Fish Populations See Rapid Decline Emily Sohn for Discovery News | Tue Sep 1, 2009 Efforts to protect rapidly declining freshwater fish populations may not be enough. What can we do about this? Project #3: Make a flyer to educate about purchasing fish caught using sustainable methods. Examples: • How to find and use a sustainable fish chart at your grocery store or restaurant and why using it is good for the earth. • Five quick steps that anyone could take to discover whether the fish you are eating at the dining hall or at your local grocery store is sustainable. • Reproduce a sustainable fish table and make an extra improvement to the table, such as common names for these fish or names for sources like brands of fish sticks. Example: More people want to know source of food By Laura Giovanella, Media General News Service Published: September 18, 2008 “Bertini said that Wendy’s new fish sandwich - an upgrade from fish sandwiches of the past once available at some of the chain’s restaurants - is made from cod caught by fisherman in the North Pacific Ocean but did not name suppliers. An earlier version of Wendy’s fish sandwich was made of a mix of North Pacific and Atlantic cod, he said. Pacific-cod fisheries are generally sustainable, according to the Monterey Bay Aquarium’s Seafood WATCH Web site1; Atlantic cod has been over fished and should be avoided.” Convince Me • Your assignment should convince someone to learn about where their fish is caught and how. • Using Wendy’s example, come up with a list of 3 things that should have been added to better convince you. • List 1 point of evidence that should have been used to demonstrate that the fish is sustainable.2 Basic Population Dynamics Learning Objectives: 1. Review population growth curves, r, R, and K 2. Discuss factors used to calculate population growth 3. Describe the information you would need to know about a population to estimate population sizes and choose the best method to estimate population numbers for an organism 1. Population Growth Curves Question 1 These growth curves are for cod populations in 4 different fishing regions. Use what you know to determine R for each curve below. Then, use that information to choose the fishing area you would be LEAST likely to purchase sustainable fish from. A B C D 1. Population Growth Curves Biomass estimates for Pacific cod in the Gulf of Alaska 1978 – 2004 Question 2: Write a figure legend for this graph. Include claim, describe evidence 1. Population Growth Curves Question 3 The total commercial catch for Georges Bank Atlantic cod over all gear types in 2000 was 9,200 metric tons, while for Pacific Cod in the Gulf of Alaska it was 59,563 in 2010. The population growth curve for Georges Bank is shown below. What is the growth rate (R) for this population? A. 0.1 B. -0.1 C. 0.0 1. Population Growth Curves Growth Exponential: occurs when R is positive Decline But exponential growth is unrealistic- it rarely happens in nature 2. Factors influencing population growth What should we measure in a population to determine what type of growth it has? 2. Factors influencing population growth Question 4 Which of the following do you think is NOT necessary to measure to determine population growth? A. Birth rate (b)- # babies born B. Death rate (d)- # individuals that die C. Number of fish spawning (s)- # spawn D. Immigration rate (i)- # individuals that join the population E. Emigration rate (e)- # individuals that leave the population Explain 2. Factors influencing population growth Question 5 Use the elements you would measure from the last slide (b, d, s, i, e) to develop an equation that describes total population change for Atlantic cod. N = 100 Ktons in year 1 ---> N = 100 Ktons in year 2; population growth = 0 Equation: 0 = ___________________ Check your equation using the numbers for the cod described here in Ktons. (Is the population growth zero using your equation?) b = 20 d = 20 s = 20 i = 20 e = 20 2. Factors influencing population growth Question 6 Your group’s equation was: A. N = d - b + i + e B. N = i - e - s + b - d C. N = s - d + i - e D. N = b - d + i - e 2. Factors influencing population growth Question 7 The following cod population (1000 tons) has the following: b = 390 tons d = 290 tons (fishing) i = 100 tons e = 50 tons Is R +, -, or 0 for this population? Are we worried about this population? Why/why not? 2. Factors influencing population growth 3.Gathering information about populations N=b–d+i-e How do we even know the number of individuals in a population? 3.Gathering information about populations Several widely accepted methods, we will talk about three: 1. Capture/Kill 2. Census 3. Mark Recapture 3.Gathering information about populations 1. Capture/kill 3.Gathering information about populations 2. Census 3.Gathering information about populations 3. Mark recapture 3.Gathering information about populations Question 8 Which method do you think they are using in the case of cod? A. Capture/Kill B. Census C. Mark Recapture 3.Gathering information about populations Question 9 Not recommended Recommended This data shows female spawning biomass and landings and catch which includes all fish caught, even those that are caught but not retained. Write another figure legend that includes a claim, and explanation for why one population is recommended over the other. Describe this evidence. Include a description for the reader about what you see in the graphs such as the total number of the population.