Embed Size (px)
Citation preview
What is the status of fish stocks around the world and the role of fisheries management?
Ray HilbornSchool of Aquatic and Fishery Sciences
University of [email protected]
Thanks to collaborators
Thanks to unknown colleagues
Thanks to the thousands who collect the data
All fish gone by 2048
Science 2006
Science 2006
A new consensus on stock status
www.ramlegacy.org
What is in a stock assessment?• History of abundance• History of catch, recruitment, fishing mortality• Estimates of reference points
2009 Paper
Stock Coverage
Open access https://www.pnas.org/content/117/4/2218.short
Trend in abundance and harvest rate
Stock Size
Fish
ing
Pres
sure
Fully Exploited
Overfishing
Under exploited
Overfished and
overfishing
Over fished
Yield lost from fishing too hard
Yield lost by overfishing (red) and underfishing (yellow)
From Hilborn and Costello 2017. Marine Policy. The potential for blue growth in marine fisheries yield, profit and abundance of fish in the ocean.
Abundance of stocks (expert opinion)
Summary of stock status
• Some places never overfished• Some were overfished and now recovering• Some continue to be overfished• Where we don’t have assessment data we generally
believe status is poor• Even in well managed places there are stocks in
poor condition due to ineffective management and natural variability
How are fisheries managed?
Research• landings data
• body size or age data
• surveys to monitor trends in abundance
• stock assessments
Management• objectives and fishery management plan
• regulations to limit fishing pressure
• capacity to adjust regulations and fishing
pressure
Enforcement• dockside monitoring /at-sea observers
• penalties and compliance
• protection of sensitive habitats
• discarding and by-catch measures
Socioeconomics• controls on access and entry
• transparency
• community involvement
• capacity-enhancing subsidies
Intensity of fisheries management
Overall intensity of fisheries management
What do we know about the rest of the world?
Where we don’t have assessments
Source: Global Assessment Database (ramlegacy.org)
www.ramlegacy.org
Abundance of stocks (expert opinion)
West coast Malaysia from TrawlBase
Rebuilding requires reducing fishing pressure
• This can be achieved in many ways– Hard TAC’s– Reducing fishing effort– Time area closures
• BUT you have to be able to enforce the regulations
• With VMS effort is easily monitored
Take away message
• Fisheries management works if applied• We have methods that work to
– Sustainably produce food from the ocean– Protect sensitive biodiversity
• The key to producing food and protecting biodiversity is to manage 100% of the ocean– Not to close 10% 20% or 30% of the ocean to
fishing
www.ramlegacy.org
https://rayhblog.wordpress.com/
https://sustainablefisheries-uw.org/
https://sites.uw.edu/trawlingbp/
