For the latest issue of Edible San Francisco — “The Fish Issue” — I contributed some interesting and revealing statistics about seafood in general and abalone in particular. For example, about one-third of the wild fish harvest is used to make animal and fish feed (the source of this figure is at the bottom of the post). The fish are generally ground up, mixed with other ingredients to make pellets or a granular substance, then fed to farmed fish, hogs, chickens and other animals.
The abalone numbers are an ‘infobox’ in an article about abalone farming by Marcia Gagliardi (author of the Tablehopper e-newsletter). Marcia writes about abalone biology, recreational abalone hunting, and the abalone farming industry. It turns out that farmed abalone is one of the few aquaculture products that you can feel good about eating — it’s a low input animal (they eat kelp, which grow at alarmingly fast rates, perhaps a foot a day) and produce little waste. But it takes a long time for abalone to reach market size, so when they appear on restaurant menus or fish counters the price can be as shocking as the water off the coast of Mendocino County (one of the best places to hunt for abalone).
Numbers alone do a decent job of showing how California abalone stocks were destroyed in the 20th century, but a graph is much clearer (worth a thousand numbers, so to speak). The figure below shows the annual commercial harvest from 1920 to 1996 using data from a 2003 report from the California Department of Fish and Game. (click on the graph to see a larger version)
Without any regulations to slow them down, harvesters caught abalone as fast as they could, decimating the population in a few decades. The large dip in the 1930s and early 1940s is the result of the Great Depression and World War II (most of the abalone fishermen were of Japanese descent and were imprisoned by the U.S. government soon after Pearl Harbor). It’s worth noting that abalone are somewhat more vulnerable to overharvesting because they spend their entire lives in a relatively small area attached to coastal rocks.
As a comparison, consider the Dungeness crab. Thanks to careful management of the fishery by state regulators, good behavior by the crabbers (observing the limits, taking only male crabs, etc.), and the nature of the crab (they are caught in traps, not hand harvested), the population is relatively stable.
“Effect of Aquaculture on World Fish Supplies,” R.L. Naylor, R. J. Goldburg, et al. (2000), Nature, volume 405, pp. 1017-1024.