A few weeks ago I wrote about food chains and food webs, and why overly finicky eaters in the marine world could lead to less stable ecosystems. There's one marine food web that is of great importance to human beings... the one that includes us! I'm not referring to surfers or bathers that, on those rare occasions, get nibbled on by sharks. I'm referring to the food webs where we are the top carnivore!
Seafood makes up an increasing percentage of the American diet. Just a few years ago 4.2 BILLION pounds of it were consumed in the USA alone! My share was less than 100 pounds, most of which was plankton I swallowed underwater. We eat more than 375 million tons of tunafish alone... and that doesn't include the ones processed for catfood. Occasionally we don't even bother to cook it based on the popularity of sushi and sashimi restaurants in the US.
To quench our hunger for seafood, the commercial fishing industry has employed modern technologies including satellite imagery, sonar and aircraft not to mention huge nets and long lines that stretch 50 miles. No longer do we have to salt local catch to preserve them for later meals as our ancestors did. Modern transportation has allowed Americans to feed on species from Indonesia, Antarctica or South America within days of its catch... taking food resources away from the local residents in the process. Although many are quick to blame the commercial fishermen, WE are the ones who often make the choices regarding what goes to market.
Most of my readers are aware of the declines in many of our local species. Just 100 years ago schools of yellowtail plied the waters of Avalon Bay "forcing" ministers to leave churches and join their congregations casting fishing lines where the Pleasure Pier or Cabrillo Mole now stand. The abalone are largely gone. Both white and black seabass might have joined them had stricter laws not been passed to protect them and conservationists not worked hard to introduce new stock (including the white sea bass raised here in Catalina waters).
Our take of the world's marine resources is phenomenal. Yet we must add to the portion we eat, the portion that is killed as "bycatch." These are fish and invertebrates accidentally taken in nets or on hooks with the target species, and often discarded. The overall bycatch is estimated at 25%. When I spent a day on a shrimp boat off mainland Mexico 30 years ago, the bycatch far exceeded the actual catch of shrimp. Although my students and I collected part of it for the Los Angeles County Museum of Natural History, much of it was tossed back in the sea.
The commercial fishing practices of bottom trawling and dredging not only capture such bycatch, but also destroy much of the habitat required to support future generations to replenish what was taken. The bottom is literally scraped by the trawl thereby dislodging rocks, disturbing the upper sediment, killing sponges and other marine life that provide homes for the young fish that escape the trawl.
In June of 2003 the Pew Charitable Trust published a report on the state of our oceans. Its findings were startling, especially since the commission included not just environmentalists, but commercial fishers and corporate representatives and all agreed with the findings. Many of the fisheries we have come to depend upon are simply not sustainable at current rates of harvest. We have greatly simplified the marine food webs and in the process introduced instability.
In addition, farming of marine species such as Atlantic salmon and shrimp was found to have sufficient negative impacts on the environment that these aquaculture practices should be curtailed. Currently farming and other aquaculture efforts produce 25% of the seafood we eat.
I have dispensed with much of my usual humor while writing on this subject. If we want our children and grandchildren to eat seafood other than barnacles and jellyfish, WE all need to do something. Individuals with rod and reel catching fish locally are not the problem, as long as they follow appropriate Fish & Game laws. We as consumers must make wiser choices regarding the fish we buy in grocery stores or eat in restaurants.
Many of my friends have started carrying wallet cards like those provided on the Monterey Bay Aquarium (http://mbayaq.org/cr/cr_seafoodwatch/sfw_regional.asp) and Audubon Society (http://audubon.org/campaign/lo/seafood/cards.html) websites. Then you'll know why you should avoid Atlantic salmon, Atlantic swordfish (one of my favorites), "Chilean" sea bass and orange roughey and choose Alaskan wild salmon, Pacific halibut, albacore tuna and white seabass instead. Bon appetite!
© 2003 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays.
Image caption: Examples of "bad" and "good" seafood
farm-raised Atlantic salmon and wild Alaskan salmon
This document maintained by
Dr. Bill Bushing.
Material © 2003 Star Thrower Educational Multimedia