Fisheries Myths. Ray Hilborn School of Aquatic and Fishery Sciences University of Washington

Fisheries Myths Ray Hilborn School of Aquatic and Fishery Sciences University of Washington

Thanks to collaborators

Full disclosure of funding

Myths to be addressed Stocks worldwide are declining Eating fish is bad for the environment The act of fishing destroys the environment

Take away message The status of fish stocks and the sustainability of fisheries is variable some places good, some places bad Fish are generally produced at a much lower environmental cost than alternative forms of protein Bottom trawling impacts are highly concentrated most benthic biota are not particularly impacted some benthic species are very sensitive and those need to be identified and managed

The history of Gloom and Doom Science Magazine 1993 Fish stocks are inevitably overexploited before effective management is initiated

Global catch MTL Pauly s 1998 Fishing down food webs Pauly et al. (1998)

Nature 2003

All fish gone by 2048 Science 2006

Source: Time magazine, November 2006

What the public believes Stocks worldwide are declining Eating fish is bad for the environment The act of fishing destroys the environment

A new consensus on stock status

www.ramlegacy.org

Most assessed stocks in North America, South America, Europe and Oceania Source: Global Assessment Database (ramlegacy.org) www.ramlegacy.org

Are there plenty of fish in the sea? By country Particularly good: US, Iceland, Norway, New Zealand Improving rapidly: European Atlantic Of concern: Japan, Latin America Particularly bad: Mediterranean, NW Africa Unknown but probably bad: Most of S and SE Asia

Looking at 75% of the stocks

Abundance of harvested species

All stocks

Were the Prophets of Doom correct? Ludwig Hilborn and Walters 1993 For much of the world yes, overexploitation was the norm before management was imposed BUT there were exceptions, New Zealand and Alaska stand out as regions that absorbed the lessons of the rest of the world, and because they developed industrial fishing much later avoided any systematic overfishing

Global catch MTL Fishing down food webs Current data Pauly et al. (1998) Branch et al. (2010) Nature 468:431-435

Demise of world tuna stocks From Juan-Jorda et al. 2011. PNAS.

Past icons of fisheries failure that are now success stories Patagonia toothfish MSC certified Orange rough in New Zealand recommended for MSC certification Atlantic bluefin tuna - rapidly rebuilding

What the public believes At least Daily Star readers Experts have warned that cod are all but extinct

North Atlantic Cod abundance 9,000,000 8,000,000 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000,000-1970 1975 1980 1985 1990 1995 2000 2005 2010

Should you eat fish? What is the environmental cost of the alternative?

CO 2 per 40 g protein

Nutrient release per 40 g protein

Imagine you could produce high quality protein Without draining our rivers and aquifers Without polluting rivers with fertilizers Without antibiotics Without causing soil erosion Without chopping down rain forests

Organic vegetable field my wife farmed

Total loss of native biodiversity in this organic vegetable field

My son modifying biodiversity

Trawling footprint is growing

Motivation and funding Walton Foundation and Packard Foundation proposed the study in consultation with National Fisheries Institute We assembled the international team Funding for 4 meetings, and 2 post-docs Additional funding from CSIRO (3 year post-doc), NOAA, FAO, ICES and 10 fishing companies.

20 million tons of fish caught by trawling An important element in food security, and employment in many countries

Phase I Trawl Footprints

Collecting the data - Vessel Monitoring System - Logbook data - Effort timeseries

High resolution mapping of trawling global footprint

Global footprint of trawling

Trends in effort

What have we learned so far? Trawl effort is highly concentrated with many areas untrawled, some areas have high trawl pressure 90% of effort takes place on small portion of the bottom In fisheries where we have data, trawl effort is declining Scale distorts estimate, fine scale best Footprint is variable among regions

Phase II

50 0-50 Global distribution of comparative studies Control-Impact Gradient Single commercial trawl event -100 0 100 200 30 38 40 40 42 44 50 46 60 48 50-200 Figure by Jan Hiddink -72-70 -68-66 -64-10 -5 0 5 10 15

Aggregated effects of different fishing gears across all habitat types. A rank order of impact emerges: 1. Scallop dredging 2. Beam trawling 3. Otter trawling Figure by Jan Hiddink sqrt Relative abundance or biomass Sqrt relative abundance or biomass 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 sqrt Trawling frequency ( y 1 ) Otter trawling OT Beam trawling BT Biogenic Gravel TD Sand Sandy mud & Muddy sand Mud Scallop dredging Sqrt trawling frequency per year

Phase III. Net impacts on biota Data sources Trawl Footprint Phase I Mortality from net passage Phase II Recovery time Phase II Habitat maps from DBSeabed Result Depletion of each taxa relative to a no-trawl case

Phase III: Net impact on biota

Phase IV: ecosystem impacts on target species Evidence that epibenthos is important for some species thus theory that reducing epibenthos reduces production of some species Some experimental evidence that trawling improves productivity of flatfish Areas of most concern are places with lots of epibenthos how much of the bottom has this, what is the strength of impact? No real empirical evidence for population level impact heavily trawled areas continue to produce strong year classes of dependent species

Phase V Best Practices Evaluate but not recommend Freeze trawl footprint Prohibition by gear type (e.g. rockhopper gear) Gear modifications Benthic biota by-catch quotas Habitat impact quotas Broad scale habitat management Small scale sensitive habitat protection Rolling hotspots Effort reduction

Trawl Conclusions Trawling footprint is highly concentrated with some places intensively fished, many places not fished Most benthic species are not sensitive to occasional trawl contact -- but some are Overall most benthos largely unchanged by trawling Most concern is about the relatively small amount of sensitive species and their habitat

Myths Conclusions The status of fish stocks and the sustainability of fisheries is variable some places good, some places bad Most developed countries are stable or increasing Developing countries without effective management systems are where most problems occur Fish are generally produced at a much lower environmental cost than alternative forms of protein Bottom trawling impacts are highly concentrated most benthic biota are not particularly impacted some benthic species are very sensitive and those need to be identified and managed