Biology 1229Fisheries…

or… Should fish be on the menu?

Fish on the menu…At least 2.5 Billion people

depend on fish for more than 20% of the protein in their diet

97 % of fishers are in developing countries

Why might fish be on the list?Mercury

Why might fish be on the list?Farming practices unsustainable

Shrimp farming in Mexico destroys mangrove forests

Salmon farming Escapes Parasites Eutrophication

Why might fish be on the list?Fishery unsustainable or

environmentally damaging

Bottom trawling

Bycatch from a shrimp net!

Unsustainable fisheries

How does a harvested population work?

Note: “sustainable” is economic, not based on the population!!!

It is possible to derive a MSY from population data using growth rate and harvest rate

Orange RoughyHoplostethus atlanticus Slow, ugly, demersal fish

(“Slimehead”)Mature at 20-30Live up to 156 years (depending

on who you listen to…)Harvested by bottom trawling

around sea mountsFishing, or mining?

How much of the ocean is harvested?

Fishing down the food web

How many fisheries are sustainable?

What about recreational fishing?Commercial Fishery

Recreational fishery as a %age of commercial

Including menhaden and pollock

But the vast majority of several high-value, threatened species (e.g. Red Snapper) are caught recreationally

We are catching too many fish!!

Not just fish suffer…Effects on seabirds & other top

predatorsEffects on erosion and flood

control (e.g. New Orleans)Economic effects of fishery

collapse (Newfoundland)

Top 20 countries for unsustainable fishing…1. China2. Peru3. Japan4. Chile5. USA

18. Canada

What future?Some authors predict the

collapse of ALL fisheries by 2048Sustainable management is

possible… requires Reliable data Reliable fisherman A pretty decent navy

End of oil may result in reduced fishery pressure

Ownership of fisheries prevents collapse

Number of Individual transferable quota (ITQ) fisheries

With ITQ

Without ITQ

See also

http://www.mbayaq.org/cr/seafoodwatch.asp