Marine Resource Issues
Sabellid Infestations of California's Aquaculture Facilities

From Ray Fields:

An Aquaculturist's Perspective

As promised in my last post that forwarded a response from a CDFG researcher (Carolyn Friedman) to a letter signed by 40+ scientists concerning the Sabellid worm and it's introduction to California waters via aquaculture, I am forwarding the response received from the president of a California aquaculture facility (with his permission). The delay in forwarding this information was caused by a need for me to repackage the text from one file format to one compatible with e-mail. In the process, some text was lost. My apologies are extended in advance for any inaccuracies that may be unintentionally introduced as a result.

Rocky Daniels
norcadiver@sonic.net

Dear Mr. Daniels,

I have enjoyed your posts on the ABNET regarding the poaching and legislative issues regarding abalone. It is obvious that you have devoted a significant amount of time and effort to following these issues. Now that you are giving the sabellid worm your attention, I think it is important that you get some information from someone other than Mr. Cohen. While it is true that Mr. Cohen may be a recognized expert on introduced marine species, I am willing to bet that he has never even seen a sabellid worm. We have corresponded several times, and I have repeatedly invited him to visit our facility (an invitation that I am happy to extend to you also) in order to better understand the sabellid problem and the steps the abalone aquaculture industry has taken to combat it. He has so far declined these invitations.

I would like to address several points contained in Mr. Cohens letter, but first let me offer a little background information on the sabellid problem in abalone aquaculture. In the late 1980's, a small number of our cultured abalone exhibited deformed shells and reduced growth rates. One of our employees suspected that it was being caused by a native species of polychaete that is known to inhabit abalone shells. As you are well aware, abalone and other gastropod shells are home to many different organisms, from polychates to sponges to boring clams. One of these deformed shells was sent to a recognized expert on this organism, and he responded that we did indeed have polydora in the abalone. Over the next several years we attempted to quarantine the deformed shelled abalone, and we also began to hear of other farms experiencing similar problems.

It wasn't until 1994 that another grower sent a sample to another scientist, who discovered that the problem was being caused by an organism that was completely unknown at that time. He was able to determine that it was a polychaete of the sabellid type, due to the presence of the brachial crown. At that point, our research scientist, Dr. George Trevelyan, discovered the method of the worms reproduction and spread. It became obvious that our efforts at culling the deformed abalone, which we had been attempting for years, were futile as the deformation of the shell does not occur until many hundreds or thousands of these worms exist on a single abalone. George was now able to identify abalone that were host to very small numbers of worms, although it did require killing the abalone to examine the inside of the shell.

Using this new information, we proceeded to destroy in excess of 500,000 of our juvenile abalone that were host to previously undetectable levels of worms. We also had to change virtually every aspect of our husbandry procedures to allow the now clean juvenile population to remain quarantined from the remainder of the abalone. We also hosted a meeting at our farm for all interested abalone growers in order to share this vital information. The abalone industry formed the Abalone Sabellid Worm Advisory Committee, made up of representatives of the abalone aquaculture industry, to try and obtain research funding and facilitate the sharing of any information obtained amongst the growers. Professor Kuris of UCSB began to study the worm, and together with support from the abalone aquaculturists, was able to secure Sea Grant funding to study this problem. Many of us in the industry also donated funding to support their research before the Sea Grant funds became available. A co-worker and I wrote a paper on what we new about the sabellid at that time, with drawings by Dr. Trevelyan, and we presented it at the 2nd International Abalone Symposium in Hobart, Australia. At this time, the worm was still a completely unknown species.

Shortly after the symposium, I received an e-mail from Kevin Ruck in S. Africa. He was attempting to culture the S. African abalone, and had been experiencing problems with deformed shells. He had heard about our presentation at the symposium, and we exchanged shell samples. All the parties involved came to the conclusion that they were indeed caused by the same organism, and that it was native to S. Africa. Thus, it was not until 8+ years after we began experiencing problems that everyone involved became certain that we were dealing with an introduced species.

Regarding Mr. Cohen's letter, it is very easy to sit back with 20/20 hindsight and criticize the parties involved. Obviously, if we knew in 1988 what we know now, we could have avoided virtually all the problems associated with this pest. I think it is especially ironic that Prof. Kuris and Carrie Culver are attacking CDFG's response as inadequate, since CDFG'S regulations are exactly those that Prof. Kuris and Ms. Culver recommended in November 1996. I also feel that CDFG has taken a balanced approach that realistically addresses the risk associated with this pest. It is very important to note that all of the problems caused by the sabellid have only been observed in the aquaculture environment. There has never been an instance of any visible impacts on any gastropod outside an aquaculture facility. While the letter states that high abundance of worms have been seen in S. Africa, it does not go on to point out that, while it may be present in many species, it dose not visibly interfere with the host. The only negative impacts in S. African abalone are in the aquaculture facilities, undoubtedly due to the high crowding and food density available.

I think it is very pertinent that this organism was not even discovered until we had problems with it, despite its presence in the S. African abalone, a species that has been exhaustively studied for many years. As far as its presence in any organisms in California waters, it takes a trained person with a microscope to find any evidence of its existence. There is no free swimming larval phase to allow for widespread disbursement of the larvae, and most abalone farms are geographically isolated from any significant abalone populations.

Again, I feel that CDFG has taken the correct action by allowing the farms some time to get rid of their infested stocks. At our facility, the number of severely affected abalone has been reduced from in excess of 2.5 million to about 400,000. We hope to have these abalone marketed by year end. If all the farms were to be required to immediately dispose of all their affected stocks, it could very easily kill the entire nascent industry.

You be assured that no one is more interested in eliminating this pest than the growers, at it poses a very significant threat to our survival. However, we are confident that we have it under control at our facility. We have eliminated it from our juvenile seed stocks, and we are able to keep the abalone sabellid free in our growout tanks. As far as the discharge of larval worms, the screens have been very effective in eliminating the shells and debris that used to wash down the drain. As Prof. Kuris has stated, this debris posed the greatest threat to the environment. The very fact that we have 6 times fewer infested abalone than we did just 1-2 years ago would argue that the risk of contamination by larvae in the discharge has been similarly reduced.

The letter also states several principles that the signers believe aquaculture management should be based upon. I think that you will find most of the abalone aquaculturists share these same sentiments, and I believe that abalone aquaculture here in California has been based upon most of these principles. For example, it is based on a native stock. To my knowledge, very few (maybe 1) abalone growers have imported any non-native species. The only significant movement between farms is when producers buy their seed from hatcheries. This seed is required to be inspected by CDFG now. It is true that it was not in the past, but it is also unlikely that such action would have prevented the problems we now face as no one may have noticed a previously unknown, virtually microscopic organism. I am sure that most of the growers who received seed abalone that were host to the sabellid had no idea that their seed could have ever been exposed to non-indigenous organisms. As aquaculture operations by definition require water to grow their crops, it is perhaps unreasonable to hold CDFG responsible if these crops become exposed to any of the many non-indigenous species released into our waters by other acts of man, i.e. the bilge water from foreign ships.end to you also) in order to bes pest. I think it is especial

The CDFG has inspected every abalone facility at least once to verify the level of infestations and to address compliance with the new regulations. Upon repeat inspections, some growers have already been shown to have eradicated the worm from their facilities. We all need to learn from this experience and not repeat any mistakes that may have been made in the past. To the point that Mr. Cohen's letter address this concern I am in complete agreement. However, we need to deal with the sabellid worm as the situation is now, not as what we could have done in the past. The abalone growers and the CDFG agree on that point, and are both working diligently to eradicate the pest from aquaculture facilities and prevent any damage to the environment.

Again, I would like to extend an open invitation to you to visit our farm. I don't know where you are located, but I presume it is in N. Calif. I know that we are quite some distance away, but I am sure that you would find our operation very interesting. With the recent closure of the Calif. commercial abalone harvest, and the reductions or closures of virtually every other abalone fishery throughout the world, aquaculture may be the only source of commercially available abalone some day. I only hope that the industry here in the US is given a chance to survive and be apart of it.

Sincerely,
Ray Fields, President, The Abalone Farm