overfishing

1. Global Fish
Stocks- a catastrophic
and irreversible decline?
Ashlee Maywald, Emily Megin,George River
Ellis, Maverick Penman,Nompumelelo
Mphele, & Patrick Ashton

2. How Did We Get This Far?
A history of fishing and exploitation
Image: http://www.bbc.com/future/story/20120920-are-we-running-out-of-fish

3. The Global Decline
• Globally stocks of fish have been rapidly falling since the
1980’s
Worm et al., 2006

4. Decline in Major Atlantic Fish
• Salmon
1950’s: 10 800
2010: 2 100 (20%)
• Cod
1970’s: 300 000
2010: 27 000 (10%)
• Tuna
1950’s: 34 000
2010: 9 600 (30%)

5. How Did This Happen?
• Industrialisation
With increased technology catch efficiency has
increased
• Misleading science
• Optimism ☺
Image:
http://www.portcastello.com/en/introduction/history/fishing-
business-and-industrialisation.htmlImage: http://imgbuddy.com/fish-eggs-in-water.aspImage: http://amac.us/personal-story-optimism/

6. Where Are The Fish Coming From?
● No more fish? Fish somewhere else!
EU and USA make deals with poorer nations for the right to fish
commercially in their water
● Local and artisan
fishers are the
usual losers
○ They may catch only
⅓ of what they used
to.
Image:http://www.marinelink.com/news/detained-fishing-trawler362553.aspx

8. The Tale of the North Sea
● Shallow, muddy and barren
● Evidence of historical abundance of sturgeon, houting,
and bluefin tuna
● Evidence of oyster reefs
Image: http://stock-clip.com/video-footage/sea+inhabitants/3

10. ●Bottom trawling
●Dynamite fishing of
coral reefs
●Top-down environmental
alterations
○Example: Norway cod
Habitat Destruction

11. Reduction of biodiversity
● Reduction of desired phenotypes
○ selection on length-at-age
○ selection on location
● Miniaturization
○ earlier sexual maturity

12. Destabilization of the food chain
● Predator / prey interaction
● Change in age structure
- Large reduction in biomass
- Example: tiger flathead

13. Marine pollution
●Anthropogenic
●Alters reproductive systems
●Disruption to coral reefs
●Affects entire food chain

15. Solutions

17. Safe Catch Limits
http://qsr2010.ospar.org/en/
media/chapter_pdf/QSR_Ch
08_EN.pdf

18. Safe Catch Limits
needs to be reassessed
regularly
scientifically determined
NOAA Magnuson
Stevens Fishery
Conservation &
Management Act (2007) http://wildliferesearch.org/category/overfishing/

19. Reduction of By-catch
http://www.biznews.com/green/2014/0
5/27/infographic-everything-need-
know-bycatch/

20. http://www.underwaterbaitsetter.com.a u/bait-
setter/the-baitsetter/
Gear Modifications

21. Catch Share Programs
●holds fishermen individually responsible
●helps in achieving safe catch limits
●longer fishing seasons
safer work conditions
better management performance

22. http://ww
w.edf.org/
content_i
mages/ca
tch-
shares-
world-

23. http://www.edf.org/content_images/catch-shares-world-map-hi.jpg

24. Monitoring & Enforcement Approach
enforcive legislation
data collection systems
patrol vessels
New technology: satellite & infrared tracking
subregional & regional cooperation

25. http://voices.nationalgeographic.com/2014/01/30/shark-tagging-tracking-
separating-fact-from-fiction/

26. http://www.gizmag.com/google-overfishing-global-fishing-watch/34794/

27. Marine Protected Areas
Success of MPAs in the past
Potential drawbacks of MPAs
Solution-based strategies

28. What are Marine Protected Areas?
Marine protected areas (MPAs) are protected regions of seas, oceans or
large lakes; restrict human activity to protect natural or cultural resources.
MPAs and their restrictions differ substantially between nations:
development
fishing practices and gear
fishing seasons and catch limits,
moorings and bans on removing or disrupting marine life

29. Great Barrier Reef Marine Park Authority

31. The Arrabida Marine Park, Portugal
Total Protection
No fishing or recreational activities of any kind,
navigation permitted
Partial Protection
Restricted recreational activity permitted, sport
fishing forbidden, commercial fishing very
limited
Complementary Protection
Sport fishing permitted, restricted commercial
fishing
Cunha et al. 2014

32. Improved catch
Cunha et al. 2014
MPAs implemented in 2005.
Mean daily catch measured as kg per
auction day. Increases significantly
with MPAs.

33. CPUE for three different
protection areas.
Implies a greater
abundance of target
species in areas of higher
protection.
Cunha et al. 2014

34. Positive effects of MPAs
Increase in trophic and functional diversity
Increase in top predator abundance, decrease
in herbivore abundance
Ability to target key nursery/migration regions
Spillover effects into neighbouring waters

35. Problems with MPAs
Little to no effect in areas of multiple
stable states (phase shifts)
Effectiveness decreases as
migration of species increases
Opposition from local communities
Bureaucracy - planning,
maintenance, enforcement and
review. $$$
Limited deterrence of overall fishing
pressure in some areas
Worm et al. 2009

36. MPAs: Part of the solution
Rebuilding of Kenyan small-scale
fishery with combination of measures
MPAs + gear restriction + community
cooperation led to significant
increase in commercial fishing value
Worm et al. 2009

38. Aquaculture
●How do we continue to meet the increasing
global demand for seafood?
●Aquaculture: growing aquatic species under
controlled conditions
●Real potential to reduce reliance on global
fish stocks

39. Forms of Aquaculture
● Land Based: 60% fish products
● Brackish: 32% fish products
● Offshore: 8% fish products
(Biotechnology)
(Global fishing)
(fish site)

40. Inputs
●Food
●Infrastructure
●Operational energy

41. Food
Fishmeal:
- Comprised of processed pelagic fish:
Anchovy, Sardine, Capelin, Herring
- Still marine Origins
- Key pillar of many marine foodwebs

42. Outputs
- Disease, disease deterrents
- Escapees
- Nutrients: uneaten foods, faeces

43. Management Framework
- Antibiotic/parasiticide utilisation and
environmental toxicity
- Pathogens & wild fish susceptibility
- Fish escapees
- Nutrient waste: food & faeces
- Food sources
Used to maintain standards

44. Case Study - Offshore
●Step 1:Public-Private partnership
●Step 2: Construction:
(UNH.edu)

45. Fishmeal Research and Production Facility
●Explore use of alternatives to current protein
sources
●Reduce reliance on pelagic fish species
●Trials: soya, insects, livestock carcases,
microalgae

46. Research Projects
Large scale so a number of small specific researches can
be influenced with the $3 million used in different areas.
What is the importance of research and data?
•Informs conservation management
•Effective Implementation of projects
•Increases capacity for research
•Clear results and direction from data
•Providing information

47. What Research projects have achieved
•MPA’s and zones.
•Safe catch limits.
•Reduced bycatch
•Reduced illegal fishing
•Catch share programs
•Effective aquaculture
http://www.un.org/apps/news/story.asp?NewsID=44250#.VVngUPmqqko

48. Proposed research projects
•Satellite and infrared tracking illegal fishing activity
•Fishmeal research to improve Aquaculture
•Gear modification research to reduce bycatch

49. Satellite and infrared tracking illegal fishing activity
Expected results:
Increased number of illegal fishing boats being intercepted
A more effective monitoring and tracking system
Deter illegal fishing
How this could inform management decisions:
An improved way of tracking could lead to a broader use
more research enabling more detailed and informative systems

50. Fishmeal research to improve Aquaculture
Expected results
Finding alternate fishmeal sources
Finding an environmentally economic and safe resource
How this could inform management decisions:
Would not have to enforce as it is a cheaper resource
Sustainable farming would benefit all parties involved

51. Gear modification research to reduce bycatch
Expected Results
Effective modifications reducing bycatch
Reduced bycatch by up to 30%
How this could inform management decisions:
Once proven effective it could then be applied to all fisheries using the same
technology
Reduced bycatch makes fishing practices more efficient so would be in all
interests.
http://www.nmfs.noaa.gov/by_catch/brep_2014_awards.html

52. Global fish stocks - a catastrophic
and irreversible decline?
Fig 1: Worm et al. Average catch above, exploitation below Fig 2: Influence of Aquaculture up to 2005
http://marine.rutgers.edu/~ojensen/Documents/Worm_etal_2009_Science.pdf http://www.unep.org/dewa/vitalwater/article167.html

53. References
· Clover, Charles (2006) The End of the Line: how overfishing is changing the world and what we eat. University of California
Press, California, USA
Costello, C. et al. (2012) Status and Solutions for the World’s Unassessed Fisheries. Science 338: 517-520
· Cunha, A. et al (2014) Biomares, a LIFE project to restore and manage the biodiversity of Prof. Luiz Saldanha Marine Park. J
Coast Conserv 18: 643-655
· Kurlansky, Mark (2011) World Without Fish: how could we let this happen? Workman Publishing, New York, USA
“Dire Future for Fishing.” Reporter Greg Hoy. The 7:30 Report. Australian Broadcast Corporation, 5 May 2010. TV news. Web, 19
April 2015
Takashina, N. & Mougi, A. (2014) Effects of marine protected areas on overfished fishing stocks with multiple stable states.
Journal of Theoretical Biology 341: 64-70
· Villamor, A., Becerro, M. (2012) Species, trophic, and functional diversity in marine protected and non-protected areas. Journal
of Sea Research 73: 109-116
· Voyer, M., Gladstone, W., & Goodall, H. (2014) Understanding marine park opposition: the relationship between social impacts,
environmental knowledge and motivation to fish. Aquatic Conserv: Mar. Freshw. Ecosyst. 24: 441–462
· West, C., Dytham, C., Righton, D., Pitchford. J. (2009) Preventing overexploitation of migratory fish stocks: the efficacy of
marine protected areas in a stochastic environment. ICES Journal of Marine Science, 66: 1919-1930
Worm, B. et al. (2006) Impacts of Biodiversity Loss on Ocean Ecosystem Services. Science 314: 787-790
· Worm, B. et al. (2009) Rebuilding Global Fisheries. Science 325: 578-585