Monday, October 22, 2012

Can the ocean keep up with the hunt?

I watched this video in my Wildlife Ecology and Conservation class (FW104) and answer a few questions about it. I found the information to be very important, especially to a fish lover like myself. I also wanted to pass it on because, as anyone who has been following this blog or knows me will have heard me say before, it is critical for everyone to understand where their food is coming from and how it is produced. So here is the video; it's about 20 minutes:

 In case you don't have the time to view this video here are the main ideas:

Commercial Fishing

  • The ocean is what they call a biological desert. For it's size, diversity is actually very low.
  • The fish population in the open ocean is being exhausted due to over-fishing through commercial fishing operations and pirate ships (ARR!).
  • We aren't catching the same fish species for consumption as we have in past decades. As larger fish disappear, global fleets target smaller fish, lower on the food chain. This leads to further collapses in the ocean ecosystem.
  • 20 million metric tons of fish are discarded as waste annually. Untargeted fish are called bycatch. This unintended harvest is equal to a catch 4 times that of the US fishing fleet. 
 http://jonbowermaster.com/blog/2009/06/kamchatska-v-kodiak-what-a-difference-225-years-make/
  • Fishing gear that have had considerable impact on bycatch include bottom-trawling nets (nets are run along the bottom of the ocean, capturing everything they come across) and long-line fishing (thousand of lines with hooks are trailed behind ships, with no system to discriminate species). Both forms are meant to catch large amount of fish at once and are prone to catching endangered species like sharks and sea turtles, who die before they can be returned to the water.
  • Hook fisherman leave the habitat intact by one fisherman, fishing with one pole and one hook. They catch one fish, keep it if it's what they want and throw it back if it's not. No damage is done to the ecosystem but it is not practical for the vast quantities of fish demanded by the public.
  • In extreme cases, it is very hard for fish stocks to recover, especially if fishing continues at the same rate. The solutions are to either stop fishing all together or...

Aquaculture

  • The USA is the leader in aquaculture, or the practice of farming fish. The main type of fish that are farmed are tuna and salmon.
  • The problem with aquaculture, especially tuna and salmon, is that these are carnivorous fish. In order to farm these fish, we must feed them. This increases pressures on fishing, but instead of fishing for direct consumption we fish for smaller fish to feed the larger fish for indirect consumption.
  • It takes 17 pounds of fish to produce one pound of tuna; three pounds to produce one pound of salmon.
  • Tilapia, from the Nile River, is an omnivore and can be raised mostly on plant-based proteins.
  • Catfish farming in the Mississippi delta, has experienced great successes. Feeding them has gone from 10-14% fish meal to 1-2% fish meal today. 
  • Shellfish farming is also a good business. They stay quiet, they stay where you put them and they clean up the water. They also produce vast amounts of food in a small area; according to the video shellfish could be the answer to world hunger.
 http://en.wikipedia.org/wiki/Aquaculture_of_salmon
  • There are a few risks to human health associated with aquaculture due to bioaccumulation: PCBs and dioxins are two examples.
  • Natural salmon are less exposed to bioaccumulation problems because they consume mainly crustaceans whereas farm fish eat fish meal. In fact, natural salmon have pink flesh due to their diet of shrimp and crustaceans (much like flamingos), and farm salmon are dyed pink before they are sold at market. Gross!
  • With farmed fish we are concerned about disease and infection so we use antibiotics in feed as a preventative measure; this could lead to resistant bacteria. 
  • Disease and infection is more of a problem in farms than in the wild. They use this analogy to describe this: if you stood on a football field with someone who has a cold you probably won't catch it (the wild) but if you stood in an elevator with 11 people who all have colds you will probably also catch cold (fish farm).
http://blog.zintro.com/2011/05/20/there-is-a-lot-going-on-in-aquaculture/
  • Large number of escaped farm salmon may impact the integrity of the wild population by messing with thousands of years of natural selection.
  • Tropical areas have many mangrove wetland habitats (mangrove forests) that have been displaced by shrimp farming. This destroys habitat that the people and wildlife depend on (ex. crab production and medicinal plants). A particular example is salt water released from ponds contaminated fresh water aquifers.
  • Deep water aquaculture is where net cages are submerged and anchored to the sea floor. Could be better for ecosystems than near or on land aquaculture depending on implementation.
  • Improvements in vaccines have reduced antibiotic use. Improved nets and anchors have reduced escapes, land-based tanks protect wild populations from farm-waste and disease.

Want to do something?

Unfortunately, most people don't pay attention to where their food comes from. Do you think you'll pay more attention now that you have this information?

If yes, there are many resources available to you and I hope you'll check them out:

 
  • I keep this seafood watch guide in my wallet (mine's from April 2007, a friend brought it to me when she visited California's Monterey Bay Aquarium). You can print out your own from the website. 
  • Seafood watch also has and app for Apple and Android.

http://www.123rf.com/photo_13172672_healthy-food-hot-baked-salmon-piece-served-over-glass-plate-on-wood.html


Now I love salmon as much as the next person (maybe more depending on who's next) but I know I'm going to always check where my fish is coming from, what about you?