Friday, December 22, 2006
Did Divers Drive the Black Abalone to Brink of Extinction?
The Center for Biological Diversity formally petitioned the Federal government to protect the black abalone under the Endangered Species Act. If the species is listed, it will enjoy that dubious distinction with the white abalone. The petition describes in a few short sentences the precipitous decline of the abalone along the Southern California coast and Channel Islands. The petition cites commercial and recreational overharvesting and disease as primary factors in the decline with warming ocean temperatures cited as a contributing factor among others. The petition relates that starting in 1985, dead and dying abalone were observed at Anacapa and Santa Cruz Island. Withering syndrome caused by bacteria results in tissue atrophy. An infected abalone is unable to hold onto the hard substrate and eventually dies. The document describes the spread of the disease which resulted in the disappearance of 99 percent of the population of black abalone from Anacapa Island and other locations.
I started frequently diving at Anacapa and Santa Cruz Island in the mid-1980s. In the shallows and intertidal areas, black abalones crowded about stacking on top of each other. Pink and red abalones were abundant in deeper water and occasionally a diver would find a rare white abalone approaching the edge of the sport diving depth limit. The desirability of the abalone as a food was directly proportional to its depth. Black abalones were the most abundant and easiest to find and take. They were the least desirable species because their tissue was tough with the consistency (and taste some would argue) of old shoe leather. All abalone steaks need to be tenderized using an “ab hammer” fashioned from wood or metal. One diver I knew swore that the edge of the bottom of a 12-ounce Coke bottle worked equally as well. Many of us believed the easiest and only way to tenderize a black ab steak was to run steamroller across it a few times and as a result we took very few if any, especially when other species were relatively plentiful. My favorite recipe was to coat the ab steak in Italian bread crumbs, stuff it with Monterey jack cheese and avocado and lightly fry the entire concoction.
Within a couple of years I noticed that the black abs were disappearing and that there seemed to be a lot of black ab shells in the shallows. About the same time I began to hear of an mysterious ailment that was working its way through many abalone species, not just the black abs. Called the “withering foot syndrome” there were several competing hypotheses as to its cause—warm water from the El Nino events which were just becoming to be understood at that time; some kind of a parasite; pollution from offshore oil development; bacteria from run off; or a cyclic event in the little understood natural history of the species. Many scientists at the Marine Science Institute at the University of California at Santa Barbara worked on the problem. I would hear about it in Friday afternoon get-togethers sponsored by various labs at MSI. The cause was also the subject of endless speculation among graduate students and undergraduate marine biology majors, many of whom I dived with as part of the UCSB Dive Club. Also, my best friend worked in one of the labs and we would talk about this and other trends as we traversed the southern Santa Barbara County coastline in search of new dive spots. One-by-one the possible causes of the syndrome were eliminated through solid scientific research.
I am a bit surprised that the CBD petition lists recreational take as one of the contributing factors to the abalone’s demise. That is not my experience. We took what we needed for immediate consumption, seldom taking the limit, and almost never taking blacks for the reasons cited above. But then I recall a statement by Howard Hall. “For many years I've been calling this phenomenon, the ten year syndrome. Specifically a diver's first dive in an environment becomes his baseline. Ten years later, the environment seems "dived out," a term used by divers to punish themselves for environmental degradation they largely had nothing to do with, but being ignorant of other causes, blame the degradation on the impact of divers.”
I started frequently diving at Anacapa and Santa Cruz Island in the mid-1980s. In the shallows and intertidal areas, black abalones crowded about stacking on top of each other. Pink and red abalones were abundant in deeper water and occasionally a diver would find a rare white abalone approaching the edge of the sport diving depth limit. The desirability of the abalone as a food was directly proportional to its depth. Black abalones were the most abundant and easiest to find and take. They were the least desirable species because their tissue was tough with the consistency (and taste some would argue) of old shoe leather. All abalone steaks need to be tenderized using an “ab hammer” fashioned from wood or metal. One diver I knew swore that the edge of the bottom of a 12-ounce Coke bottle worked equally as well. Many of us believed the easiest and only way to tenderize a black ab steak was to run steamroller across it a few times and as a result we took very few if any, especially when other species were relatively plentiful. My favorite recipe was to coat the ab steak in Italian bread crumbs, stuff it with Monterey jack cheese and avocado and lightly fry the entire concoction.
Within a couple of years I noticed that the black abs were disappearing and that there seemed to be a lot of black ab shells in the shallows. About the same time I began to hear of an mysterious ailment that was working its way through many abalone species, not just the black abs. Called the “withering foot syndrome” there were several competing hypotheses as to its cause—warm water from the El Nino events which were just becoming to be understood at that time; some kind of a parasite; pollution from offshore oil development; bacteria from run off; or a cyclic event in the little understood natural history of the species. Many scientists at the Marine Science Institute at the University of California at Santa Barbara worked on the problem. I would hear about it in Friday afternoon get-togethers sponsored by various labs at MSI. The cause was also the subject of endless speculation among graduate students and undergraduate marine biology majors, many of whom I dived with as part of the UCSB Dive Club. Also, my best friend worked in one of the labs and we would talk about this and other trends as we traversed the southern Santa Barbara County coastline in search of new dive spots. One-by-one the possible causes of the syndrome were eliminated through solid scientific research.
I am a bit surprised that the CBD petition lists recreational take as one of the contributing factors to the abalone’s demise. That is not my experience. We took what we needed for immediate consumption, seldom taking the limit, and almost never taking blacks for the reasons cited above. But then I recall a statement by Howard Hall. “For many years I've been calling this phenomenon, the ten year syndrome. Specifically a diver's first dive in an environment becomes his baseline. Ten years later, the environment seems "dived out," a term used by divers to punish themselves for environmental degradation they largely had nothing to do with, but being ignorant of other causes, blame the degradation on the impact of divers.”
# posted by covediver @ 10:53 PM 
