Marine Science Chapters


Seaweed Mariculture

by Genevieve (Genny) Anderson, Biological Sciences Department, Santa Barbara City College

In the 1860s to the 1960s along parts of the Central California rocky coast there was a practice of the mariculturing of seaweed by Chinese. The seaweed farmers would actually burn all of the seaweed off the intertidal rocks, at low tide, in winter. Then they would wait until new seaweed would grow. (These historical images were on display, without image credit, at Rancho Marino - Ken Norris UC Reserve in Cambria, CA.)

Sea Lettuce collection at the beach
The seaweed called sea lettuce (Ulva) was one of the prized edible seaweeds and is one of the first to colonize the burned rocks. It grows very quickly and in a matter of months is ready to be harvested in the summer. Collecting would be done with a pair of baskets. (GA image)

Sea Lettuce brought up cliff in double baskets
The sites that were used for this were widely spaced and operated by one or two men (or a family), sometimes for generations. Most of the coastline where this was happening had a 20-30 foot cliff face. The seaweed was brought to the top of the cliff in the baskets. (GA image)

Sea Lettuce spread in the sun to dry
The baskets and pole (left) were set down and the prized seaweed was then spread out in the sun to dry. (GA image)

Sea Lettuce 'cakes' ready for sale
The 'cakes' of dried seaweed were packed in burlap bags and sold to brokers in San Francisco’s Chinatown. Some was shipped to China. This little known mariculture operation went on for about 100 years (1860-1960) in Central California. Now the areas are protected by State law and it is no longer legal to clear off the existing algal growth in order to encourage the growth of the prized sea lettuce. Sea lettuce is still found in the intertidal but it is only one of several dozen species found there year after year. Without the burning of the intertidal to open up space for the quick colonizers, this mariculture operation is no longer possible as there is not enough natural sea lettuce to collect, dry and sell. (GA image)

 Copyright and Credits
(Revised 31 October 2007)
 Page Back  Top  Page Forward