Option G: Ecology and Conservation

1. Option G: Ecology and Conservation G5: Population ecology (HL)

2. r and K Strategists

3. r and K Strategists • Most organisms are intermediate, exhibiting characteristics in the mid-range between r and K extremes • D. melanogaster(fruit fly) switches between strategies to suit the environmental conditions • In a predictable environment, in order to maximize fitness, it pays to invest resources in long-term development and long life (K-strategy). In an unstable environment, it is better to produce as many offspring as quickly as possible (r-strategy). Of concern is that ecological disruption favours r-strategists such as pathogens and pest species.

4. r and K strategists growth curves

5. Estimating Population Size:Capture-mark-release-recapture • Sampling technique that enables you to estimate the number of animals in an ecosystem • Steps: • Capture a sample of the population • Mark them (in an unrestrictive manner) • Release back into ecosystem • Take a second sample, some will be marked, others not • Compare the proportion of marked to unmarked

6. Capture-mark-release-recapture Mark all Individuals: Practical and ethical considerations when marking animals • How do we do this? • Colour (Paint, nail polish) • Tags, bands • Microchip • Radio transmitter • What limitations are there? • Cause no harm • Cannot make more visible to predators • Does not alter behaviour • Non-toxic

7. Lincoln Index (n3) (n1) (n2) (N) OR… Population size (N)= (n1 x n2) n3

8. n1 = # initially caught, marked, and released n2 = # caught in 2nd sample n3 = # marked in 2nd sample

10. Conservation of Fish Stocks • 5 things you need to know about our oceans: http://www.youtube.com/watch?v=s3u2ZxKhPoA Fisheries on the Brink http://www.youtube.com/watch?v=Tf1EgeHDxpA ByCatch Problems http://www.youtube.com/watch?v=B2E0QQG4Kk4 Destructive Trawling Practices http://www.youtube.com/watch?v=m2y_M40tmvg

11. Estimating Size of Commercial Fish Stocks • Studying catches – the proportion of fish stocks taken each year • Gathering information from fishers • Spawning stock biomass – the total mass of mature fish in the population • Recruitment – the number of young fish produced each year which survive to spawn • Landings – the total annual tonnage of fish landed by the fishing fleet

12. Data is collected by: • Market Sampling – landings of fish are sampled to compile information on fish length and age • Discard Sampling – the mass of fish caught and then discarded is measured • Research Vessel Surveys • Trawling • Sonar • Calculating ages • Coded wire tag detectors (capture-mark-recapture) • Mathematic modeling

13. Maximum Sustainable Yield • The maximum average catch that a stock can sustain over a long period of time without jeopardizing the maximum yield in the future • Too small=risk of over fishing • Too large=competition for food/resources • It is the optimum balance between reproductive rate and growth rate of the stock and the deaths due to harvesting and natural mortality • Harvesting at MSY requires much lower fishing rates than commonly occur in fisheries. • It takes a long series of data (>20 years) to adequately calculate a MSY value.

14. Collapse of fish populations

15. Northern Cod • Population collapse on the Atlantic Coast • Moratorium put into place in 1992 on Northern cod • Collapse due to over- • exploitation of the • stock • Meant to last 2 years, • but cod population • has not rebounded • so still closed

16. Conservation of Fish Stocks • Overfishing is a huge problem internationally. If the rate of fishing keeps up, by 2048 there will no longer be any commercial fishing. • End of the Line trailer: http://www.youtube.com/watch?v=bedirwk95Oc Fish farming http://www.youtube.com/watch?v=B77bs2aploI&feature=relmfu Bluefin tuna http://www.youtube.com/watch?v=dX4v8wyOcns&feature=relmfu

17. Cod fishery http://www.youtube.com/watch?v=-OvFpQuJHTM

19. International Measures to Promote Conservation of Fish • Monitoring stocks and reproduction rates • TAC’s (total allowable catches) and quota’s • Closed seasons (eg – breeding season) • Creation of no fish zones (exclusion zones, marine reserves) • Minimum landing size to discourage the catch of small fish • Minimum net sizes so small fish can escape • Moratoria on endangered species • Banning of drift nets which catch indiscriminately • Funding for research • Foster relationships between fishers and scientists Issues: • Enforcement is difficult in international waters and relies on trust and cooperation. • Where rules have been respected breeding stocks have recovered.

20. International Conservation Measures • Monitoring stocks and reproduction rates • TAC’s (total allowable catches) and quota’s • Closed seasons (eg – breeding season) • Creation of no fish zones • Minimum landing size to discourage the catch of small fish • Minimum net sizes so small fish can escape • Moratoria on endangered species • Banning of drift nets which catch indiscriminately • Enforcement is difficult in international waters and relies on trust and cooperation. • Where rules have been respected breeding stocks have recovered.

21. http://www.ted.com/talks/dan_barber_how_i_fell_in_love_with_a_fish.htmlhttp://www.ted.com/talks/dan_barber_how_i_fell_in_love_with_a_fish.html • http://www.ted.com/talks/barton_seaver_sustainable_seafood_let_s_get_smart.html