Guillermo Jaramillo (guillojara@yahoo.com): For hatchery folks: What is the minimum space required for natural matings of Penaeus vannamei?  I’ve seen many tank sizes and shapes, most of them large to optimize the number of broodstock, but small enough so that the mated females can be hand-captured from the sides of the tank.  Has anyone built small maturation tanks for natural mating?  What was their size and shape?

Josh Wilkenfeld (josh.wilkenfeld@gmail.com): “In the beginning”, I think that many of us tended to work with circular tanks.  The smallest size I used was about 12 feet (3.7 meters) in diameter, with a surface area of about 10.5 square meters.  Over time, as commercial hatcheries became larger and larger, construction costs and a demand for more efficient use of space moved us to bigger tanks, usually rectangular in shape, often without rounded ends, keeping at least the width limited so that workers looking for mated (open thelycum) or fully mature (closed thelycum) females could reasonably reach about halfway across the tank, working from either side.  The largest maturation tanks I’ve worked with comfortably were about 3 meters by 40 meters (120 square meters), but I think a more reasonable compromise to the goddess of cost and function would be about 3 meters by 15 meters (45 square meters).

I have not directly addressed your original question: “Has anyone built small maturation tanks for natural mating?”  It would probably help us if you would indicate the actual reason for your interest.  Knowing that one of your [Shrimp Improvement Systems, a P. vannamei broodstock company in Florida, USA, that’s owned by Indonesia’s PT Central Proteinaprima] primary objectives is development and maintenance of different species and lines of broodstock shrimp, I would guess that you are at least partly concerned with maintaining groups of animals isolated from each other, to keep them from crossbreeding, to avoid interference in studies where pheromones released in the water might affect other groups of shrimp sharing the same water, or simply for quarantine purposes.  Of course, another reason for thinking about smaller rather than larger tanks may simply be that you are working with space limitations imposed by trying to fit into an existing structure—always a frustrating experience.  In any case, here are a few things to consider when designing maturation tanks:

1. Broodstock size animals (say females of about 43 grams and males of about 37 grams) need some space to go through their chasing and mating ritual.  This can easily be disrupted if they run into right-angle corners, which they are more likely to do in smaller, but more space-efficient square or rectangular tanks.  Hence, the smaller the tank, the more important it becomes for it to be circular, or to have well rounded corners, which direct shrimp traffic around the curves.

2. Another consideration that is important in deciding tank size is the best density to work with for mating purposes.  My own experience is that the best results in terms of the percentage of females mated per night seems to be at a density of about 4-5 shrimp per square meter (using same average sizes for females and males as in #1 above), and you actually start reducing mating efficiency at densities above 8 shrimp per square meter.  For that reason, I prefer to work at about 6-7 shrimp per square meter as a compromise in use of space and mating efficiency.  Even in a situation where you prefer to work with smaller size tanks, the size of the tank may be dictated by the minimum number of spawns you need per day per tank.  A tank 12 feet in diameter with a surface area of 10.5 square meters can hold about 73 shrimp.  I usually work with a ratio of about 47.5% males and 52.5% females, so that would mean about 38 females and 35 males in 10.5-square-meter tank.  With a mating rate of about 9% females/day (a reasonable assumption for vannamei in a commercial operation), this would give about 3-4 spawns per tank per day.

3. I’m just extrapolating here, but using some of the reference numbers I’ve given above, I think you could probably work with a tank as small as 8 feet (2.44 square meters) in diameter and still get about 1.4 matings per night.

If you are not concerned about whether different groups of shrimp actually share the same water, you might consider constructing the less expensive, space-efficient, larger, raceway-type tanks and using simple but very effective dividers constructed with PVC pipe and plastic screening material.  I’ve done this on several occasions and it works very well.  Depending on the size of your compartments, you may still have to contend with the question of square corners, but this also can be dealt with through design of the dividers.

Dallas Weaver (deweaver@scientifichatcheries.com): I did some work with tanks that were five feet in diameter (about two square meters) and I think they were too small.  We got maturation, but had difficulty in getting natural mating.  We were just game playing so the information is not scientifically valid and should be viewed as one nonbiologists amateur experience.

Durwood Dugger (duggerdm@bellsouth.net): I can add a few minor comments from a cost-efficiency perspective.

If I remember correctly, the Bureau of Commercial Fisheries, which later became the National Marine Fisheries Service, in Galveston, Texas, USA, did a number of studies looking at maturation tanks in the 1960s.  As I remember, they experimentally determined that tanks 12 feet in diameter (4 square meters) were the point of diminishing returns regarding effective matings.  That became the basis for an industry norm.  Based on this work and our own, we still don’t recommend maturation tanks smaller than 4 square meters and prefer them to be at least 5 square meters.

We never recommend anything other than round maturation tanks from both a capital and operating cost point of view.  Regarding tank shape, on the basis of simple physics we believe that anything that isn’t round requires more energy and more cleaning, which disturbs and stresses the broodstock.  Consequently, as you deviate from round tank designs, you have more water quality problems, more health issues with your broodstock, and an increased risk of contaminating resulting spawns.  Circulation and self-cleaning become more hydraulically problematic when the tank isn’t round.

The increased energy inputs, labor, and maintenance costs of rectangular tanks easily offset the 15-20% loss of floor space associated with round tanks.  Not to mention that round tanks are almost always cheaper to build than straight-sided tanks because they require less material to contain equal amounts of water.  We also try to avoid concrete maturation tanks because of the sterilization difficulties associated with their typical micro-porosity and cracks, though, in some parts of the world, they are often cheaper to build.  We believe that the adaptability of portable, nonporous round tanks offer a significant premium that in the long run offsets any initial savings on round concrete tanks.  How many concrete tanks do you see moved from one area to another, or site to site?

Alfredo Medina R. (amedinar1961@yahoo.com): If my memory serves me right, the tanks constructed at a commercial installation in Mexico were 3.5 x 20, that is to say 70 square meters, and used 8 to 10 shrimp per square meter.  The mating percentage was 15%, averaging 160 thousand nauplii per female.

I really haven’t observed significant differences in the amount of sludge on the bottoms of circular and rectangular tanks,  Sludge control depends on the number of valves for incoming water and drainage.  It’s manageable.

In the case of “individual” maturation tanks or for “a single pair”, as a matter of personal opinion, I lean toward rectangular tanks of 3.5 x 7.0 meters.  As you know, there are many useful materials for constructing maturation tanks; it’s only a question of cost.

Josh Wilkenfeld (josh.wilkenfeld@gmail.com): I agree that round fiberglass tanks are ideal in many cases.

Following are some additional thoughts:

1. In some of the places that I’ve worked, obtaining fiberglass tanks of reasonable quality has turned out to be a bigger problem than one might think, and they can be considerably more expensive.  Unless what you want is an off-the-shelf product, obtaining what you want can get to be a very time consuming process including fabrication of molds, inevitable errors and shipping.  For example, when I was in Indonesia in the 1980s, we had to find a willing fabricator for elliptical/V bottom larval rearing tanks in Jakarta.  There were no capable fiberglass fabricators in the provinces where we were contracted to build five hatcheries for the government.  It took months to get the first prototypes of the various types of tanks we needed, and many more months to get them constructed and then shipped by truck/ship/truck in pieces to the hatchery sites for final assembly.  It may be easier now, but it was very difficult then.

2. As Alfredo indicated, both he and I have worked with rectangular tanks at a number of different facilities and have been satisfied with them in terms of management and productivity.  I agree that even in these non-round tanks that were designed with slopes, inlets and drains that were supposed to help keep the tank bottoms clean, we did have to siphon on an almost daily basis to keep them truly clean.

3. Portable fiberglass tanks with a one-time slick finish are indeed the ideal, but sometimes (or even many times), they don’t turn out to be a practical option.  Concrete can also be very expensive in some places, and plastered, epoxy-painted, or not, they usually turn out to be problematic in terms of a sterilizable finish.  For that reason, I almost always line tanks with HDPE liners.  When working with HDPE liners, construction with concrete hollow blocks (CHB) is often less expensive than solid concrete, and there are even less expensive solutions (banded plywood, partial sub-floor level tanks), none of which are quite as elegant as fiberglass, but sometimes, it’s necessary to make due with what is readily available.

Keep in mind that if the basic tank frame is constructed of CHB, the blocks may still need to be plaster coated before forming the HDPE liner.  Cheap blocks tend to crumble with time and/or exposure to water, and the disintegrating material can puncture the liners.  These are concerns that are also eliminated with fiberglass.  However, properly constructed lined ponds can be remarkably durable.  I visited the two SyAqua hatcheries in Mazatlán (originally the Super Shrimp hatcheries constructed in 1996 and 1997) and was pleased to find that the original HDPE liners we installed were still in use and in excellent condition.

4. With good water treatment, tank management and regular prophylactic treatments of the broodstock animals with 5 parts per million (ppm) of Copper Control (a static treatment, once every two weeks for two hours, staggering treatments so that only 25% of tanks are affected at a time), we’ve been able to keep our animals in great condition, although spawns might be reduced for about three days in the treated tanks.  We also do a quick dip of spawners in 100 ppm Argentine (followed by an immediate dip in clean seawater to avoid gill damage) before placing the shrimp in spawning tanks, and we thoroughly wash all the harvested eggs, then treat them with a 30 second dip in 50 ppm Argentine before transfer to hatching tanks, to avoid potential disease or bacterial contamination.  I don’t know if it would be possible to avoid some of this labor and handling by using round, fiberglass systems with better hydrodynamics, but I would probably take the same precautions with spawner and egg treatments in any case.

5. No doubt that siphoning is a time-consuming pain, and it does disturb the broodstock to some degree.  It’s been a long time since I’ve worked with round maturation tanks, but it seems to me that even in those tanks, it was still necessary to siphon almost daily to keep the bottoms really clean.  I agree it was probably less work (and thus less disturbing) than what has to be done in the larger rectangular tanks.

I want to make one other point regarding the percentage of mated females per night, which comes to mind after reading Alfredo’s comments.  The only time I’ve seen spawning rates of 15% a night was when we were working with a Venezuelan strain of P. stylirostris, which were truly rabbits in their reproductive capacity, especially starting with the F1 generation that we reared on site.  However, we always worked with ablated females.  During the late 1990s, Alfredo also got to work with locally pond-reared vannamei in one of the Super Shrimp hatcheries located in Mazatlán (I restricted the El-Golfo hatchery to stylirostris at that time, to maintain the virus-free status of that line of shrimp).  During my most recent work with Genitech in Mexico using virus-free, locally available strains of vannamei, I focused on production without ablation and found that at least with these shrimp (mixture of imported strains from Venezuela, Columbia, local Mexican stocks, and probably others, dating back to the late 1990s), there was virtually no difference in spawning rates, and we were actually getting more nauplii per spawn from unablated females than from ablated ones.  We averaged about 8-10% spawners per day.

Skipping off of the subject of tank size, shape, and construction materials, there are obvious advantages to working with non-ablated females, among them reduced losses from ablation mortalities, self-governing maturation frequency (better recovery of necessary reserves by females, better quality eggs and nauplii) and actual increased productivity in terms of nauplii per spawn.  It also meant that with heated and unheated water systems, we could (at least during the cooler parts of the production season), actually “turn on” some tanks by warming them to 28°C and allow others to rest by holding them at about 21°C, so that not all the females were in a constant reproductive mode.  These are things that I had hoped would be eventually achieved through hormonal inputs in the feed, so I was very happy to see that the animals in Mexico seem to have reached a state of domestication that made it possible to avoid ablation before the long-awaited breakthrough with hormonal control.

Having said this, I wouldn’t be surprised to hear that similar results have been obtained with vannamei in other places as well, and probably also with other species that have not had the same level of aquaculture attention.  I wonder if anyone has actually made significant headway in terms of controlling shrimp reproduction through feed-mediated hormonal inputs.

Guillermo Jaramillo (guillojara@yahoo.com): Thanks for all your valuable input on my question about the size and shape of vannamei maturation tanks.  The reason for my question: At Shrimp Improvement Systems, we need to maintain many lines of shrimp in our very limited maturation space.  The minimum tank size consideration is to prevent spermatophore deterioration by keeping males sexually active.  Based on your comments and with this space-limited situation, the rectangular tanks—with rounded corners—would be the best option even with all the constraints they have when compared with the “self-cleaning” round tanks.

Source: The Shrimp List (a mailing list for shrimp farmers, “shrimp-subscribe@yahoogroups.com”).  Subject: Mating area for P. vannamei.  September 6-11, 2007.

Country Reports

Bangladesh

EU Mission Will Inspect Shrimp Industry in October

A European Union Food and Veterinary Office (FVO) mission will arrive in Dhaka on October 16, 2007, to inspect hygienic conditions at every step of the shrimp farming process.  The mission is also likely to examine the operation of the liquid chromatography/mass spectrometry/mass spectrometry (LCMSMS) machine at the Department of Fisheries (DoF) laboratory in Dhaka.  The LCMSMS machine was installed at a cost of $500,000 to test shrimp for hazardous substances.  The machine went into operation on an experimental basis in June 2007 and has conducted over 15 tests so far.  The exporters, however, said the buyers might not accept the DoF tests until FVO or the USA Food and Drug Administration recognizes them as valid.

Source: The Daily Star.  Shrimps stumble in EU markets for hazardous antibiotics (http://www.thedailystar.net/story.php?nid=2627).  Abdullah Al Mahmud.  September 5, 2007.

Canada

Lobsters

The latest issue of the Lobster Newsletter (Volume 20, Number 1) is available at http://www.odu.edu/~mbutler/newsletter/index.html.  To receive an email announcement for each newsletter, contact Dr. Peter Lawton (below).

Information: Dr. Peter Lawton, Research Scientist/Director, Centre for Marine Biodiversity, Government of Canada, Department of Fisheries and Oceans, Biological Station, 531 Brandy Cove Road, St. Andrews, NB, Canada E5B 2L9 (phone 506-529-5919, fax 506-529-5862, email lawtonp@mar.dfo-mpo.gc.ca, webpage http://www.marinebiodiversity.ca).

Source: Email to Shrimp News International from Dr. Peter Lawton on September 3, 2007.

China

Feeling the Pain of the Detention

The detention of imported Chinese shrimp by the USA Food and Drug Administration in June 2007 sent shockwaves across China, with many export-oriented aquatic farm owners saying the detention might suffocate the country’s fledgling aquatic industry.  The chief of one of the largest producers of shrimp in China said: “Though there is no direct ban on the products, the high inspection imposed by the USA Customs cannot be borne by many domestic companies.  A large number of firms have been driven to the brink of bankruptcy because of the move.”  One of the hardest hit places is Zhanjiang, a port city in southern Guangdong Province, known as the “home of shrimp”.  It produces 60 percent of the province’s shrimp and 15 percent of the shrimp in all of China.  Guangzhou Hengfa Aquatic Product Company Chairman Tong Jianhui says “political friction and trade protectionism” are behind the restrictive measures.  He said: “Since China is a WTO member now, bilateral trade disputes should be solved through negotiations.  They can’t slap a ban on Chinese products directly.”

Source: China.org.cn.  Fishing Industry Battles with Troubled Waters (http://www.china.org.cn/english/business/223316.htm).  September 5, 2007.

China

The Last Supper

On August 31, 2007, The London Telegraph commented on China’s new recall system for food.  “It’s high time.  To most of Western Civilization, The Last Supper is a painting, but in China it is a frozen shrimp dinner.”

Source: Baraboo News Republic.  Opinion/Argus/Ex-astronaut cleared to appear on Jerry Springer’s show (http://www.wiscnews.com/bnr/opinion/217604).  September 5, 2007.

Malaysia

A Shrimp Farm in Malaysia

Karunanithi, manager of a tiger shrimp (Penaeus monodon) farm, submitted this report.

In August 2006, in the state of Malacca, our company, MCF Aquaculture, Sdn., Bhd., took over an abandoned shrimp farm with an area of 15 acres that including two reservoirs and ten one-acre growout ponds.

The farm is just 20 feet from the Straits of Malacca, which separate Malaysia and Indonesia.  The coastal beach and intake water is muddy.  When we took over the farm, all the pond bottoms were covered with snails feeding on the two feet of organic matter that accumulated in the pond water.  Filamentous, benthic algae and aquatic weeds clogged the ponds and reservoirs.  Iguanas had the run of the place.

At night, the scene was horrifying because that’s when the snakes, as many as 20 to 30 per pond, came out and crabs covered the dikes.  In the reservoirs, about 20 otters came fishing every night.  When we shined lights into the bushes, reflective eyes looked back at us.  Wild cats?  I don’t know.  In short, the entire farm was a replication of hell and dominated by wild beasts!

We couldn’t do much with the earthwork, but we rejuvenated the ponds and upgraded the electrical system.  When we harvested our first crop in February 2007, we got three metric tons per acre of 33-gram animals from all ten ponds.  We didn’t buy any SPF or SPR postlarvae.  We stocked PL 16s to 18s, which cost $10 per 1,000 and got a survival rate of 85%-95%.  With six feedings a day, our shrimp reached at least 25 grams in 120 days.

Due to lower prices for chilled shrimp ($5.71 a kilo for 25-gram animals), we are mainly selling to local live shrimp buyers at prices ranging from $7.71 to $8.28 a kilo.  Our production costs range between $4.85 and $5.14 per kilo.  We do two cycles a year and achieve total production of 30 metric tops per crop from ten 10 ponds.  The average salinity during the dry season is 30 parts per thousand; during the raining season, 20 ppt.  The difference in salinity has not affected shrimp growth.

During our first cycle, we used a semi-closed system, but now we are using a completely closed system.  We maintain our stocking density at 26 to 28 animals per square meter.

Our findings in the closed system ponds show reduced populations of gastropods, mollusks and barnacles compared to the previous semi-closed system.  Our 20 years experience in shrimp farming shows that smaller ponds (less than 5,000 m²) give better yields and performance than bigger ponds.

Now we are planning to further upgrade our closed system.  One of the growout ponds will be converted to a biological filtration pond where we plan to use duckweed, milkfish, mussels/oysters and bioremediation products to clean the water.  We’re focusing mainly on biosecurity measures to prevent pathogens from entering our ponds.  So far we haven’t used any chemicals.  Our shrimp are beautiful and show little size variation at harvest.

Facing decreasing prices, we are compelled to increase yields.  By increasing the stocking density up to 30 animals/m², we expect to get an additional 300 kilos per pond per crop.  We are also seriously searching for investors for a new farm at a 200-acre site.  We will joint venture with investors to explore shrimp farming anywhere in the world.

Our management team has more then 20 years experience in shrimp farming, and we provide the following services to shrimp farmers.

• Aquaculture management services

• Joint ventures

• Refurbishing of old shrimp farms

Information: Karunanithi, Taman Kekal Pengeluaran Makanan, Zon Industri Akuakultur Sempang, Lot 387, Km 20, Kampung Sempang Pantai, 77300 Merlimau, Malacca State, Malaysia (phone 606-263-2463, fax 606-263 2462, email mcf_aqua@yahoo.com.my).

Source: Email from Karunanithi to Shrimp News International on September 3, 2007.  Subject: The Beauty in the Beasts.

Mexico

Salinity Stress Test

Abstract: This review evaluates the salinity stress test (SST) as an index of postlarvae (PL) quality.  The SST is easy and does not require specialized equipment, hence its popularity.  Osmoregulation (the natural balancing of bodily fluids) in crustaceans is briefly reviewed, with particular emphasis on studies related to SST in postlarval penaeid shrimp.  Two main physiological features of osmoregulation, active ion transport through the Na+/K+-ATPase pump and fatty acid composition of membranes affecting permeability to water and ions, do not fully explain differential survival to a SST.  Other traits of the overall physiological condition appear to be involved and are not related to physiological regulation, but rather are a result of a possible increased tolerance capacity.

Source: Electronical Larviculture Newsletter (http://www.rug.ac.be/aquaculture).  Editor Gilbert Van Stappen (gilbert.vanstappen@ugent.be).  Salinity Stress Test and Its Relation to Future Performance and Different Physiological Responses in Shrimp Postlarvae.  Elena Palacios (epalacio@cibnor.mx) and Ilie S. Racotta (Centro de Investigaciones Biológicas del Noroeste, CIBNOR, Mar Bermejo 195, Col. Playa Palo de Santa Rita, La Paz, B.C.S. 23090, Mexico.  Issue 270, August 1, 2007.

Taiwan

Suspends Imports of Chinese Shrimp

On September 1, 2007, Taiwan’s Department of Health (DoH) suspended the import of Chinese frozen shrimp after detecting residues of the cancer-causing drug nitrofuran in five shipments.  In the five batches of shrimp that tested positive for nitrofuran, residues ranged from 1.1 parts per billion to 39.2 ppb.  The total amount of tainted shrimp added up to 46,000 kilograms.  Taiwan ordered the shrimp returned to China and suspended further shrimp imports until China improves its safety measures.

Taiwan bans direct trade with China, but it does conduct indirect trade through other countries, usually Hong Kong.  In the first half of 2007, Taiwan imported 2,500 tons of frozen shrimp from China.

In 2006, Taiwan suspended crab imports from China after detecting nitrofuran in a shipment.

Bureau of Food Sanitation director Cheng Huei-wen told a news conference that the DoH decided to increase its inspections of Chinese seafood from 5 percent to 50 percent of all shipments in early July 2007, after quality control issues with Chinese seafood came to light in the USA.

Sources: 1. EarthTimes.org.  Taiwan suspends import of Chinese shrimp over health concerns (http://www.earthtimes.org/articles/show/100914.html).  September 1, 2007.  2. Taipei Times.  Nitrofuran found in Chinese shrimp (http://www.taipeitimes.com/News/taiwan/archives/2007/09/02/2003376875).  Angelica Oung.  September 2, 2007.

United States

Florida—Wild Shrimp More Nutritious than Farmed Shrimp

On September 4, 2007, Wild American Shrimp (WAS) released a 13-point study that shows domestic wild shrimp is more nutritious than imported, farmed shrimp.

For the study, ABC Research of Gainesville, Florida, evaluated domestic pink, white and brown shrimp as well as farmed Pacific white shrimp from Indonesia and Thailand and black tiger shrimp from Vietnam.  Domestic wild shrimp had higher levels of iron, protein, calcium and some vitamins.  Dr. Marge Condrasky, a registered dietician and assistant professor at the Food Science and Human Nutrition Department at Clemson University, said: “A 3-ounce serving of the pink and brown wild-caught shrimp contained up to 30 percent of the recommended daily intake of vitamin B12, while the pinks had significantly higher levels of omega-3 [fatty acids].”  The study evaluated the levels of other key nutrients, including fat, carbohydrates, sodium, cholesterol, selenium, zinc and mercury.  “We know anecdotally that all shrimp are not created equally,” said WAS Executive Director Eddie Gordon.  “Now we have the science that provides further empirical evidence that wild-caught shrimp have clear benefits when it comes to taste, quality and nutrition.”

WAS is the marketing arm of the Southern Shrimp Alliance, the eight-state group of shrimp fishermen and processors that initiated the dumping case.

Source: Seafood Currents (an online newsletter from Seafood Business, www.seafoodbusiness.com).  Study says wild shrimp more nutritious than farmed (http://divcom-seafood.informz.net/admin31/content/template.asp?sid=4347&ptid=163&brandid=3138&uid=752859429&mi=182577).  September 5, 2007.

United States

Maryland—Alec Forbes, 1940–2007

From 2004 through most of 2006, Dr. Alec Forbes, a shrimp farming consultant who developed innovative shrimp farms all over the world, worked for Namibia’s (southwest Africa) Ministry of Fisheries and Marine Resources.  Alec wanted to try shrimp farming in Namibia.  In late 2006, however, he was medivacked to Bethesda Naval Hospital in Bethesda, Maryland, USA, with a severe lung problem that required a transplant.

On August 5, 2007, the Forbes family reported:

“This is Penni Forbes, Alec’s youngest daughter.  Some of you may have already been informed but for those who haven’t, I’m sorry to tell you that my father passed away on the 30th of August at 10:30 p.m.  He had some continuous problems with his recent lung transplant and the last problem was unrepairable.  A critical valve in his right lung failed on the 29th and the doctors told us that nothing could be done.  All his children flew into Virginia to be with him in his final hours.  We turned off the life support at 6 p.m., and he later passed peacefully with all his loved ones around him.  He is being cremated on Monday, the 3rd of September.  Please feel free to contact me at penniforbes@hotmail.com for more information.  He was a wonderful man and will be sorely missed by all.”

Source: Email from Penni Forbes to Shrimp News International on September 1, 2007.

United States

Virginia—Aquacultural Engineering Society

The Aquacultural Engineering Society plans to hold an “Issues Forum” ahead of the Seventh International Conference on Recirculating Aquaculture (ICRA), scheduled for Roanoke, Virginia, on July 25-27, 2008.  The Issues Forum will immediately precede the ICRA meeting.

People who want to offer sessions at the ICRA should contact Terry Rakestraw (rakestra@vt.edu) by mid-October 2007 because a more detailed announcement of ICRA sessions will be sent to press in November 2007.  Abstracts for the ICRA will be due February 1, 2008, and authors will be notified about their abstract submissions by mid to late February 2008.

Source: AES News (the online, PDF, newsletter of the Aquacultural Engineering Society, http://www.aesweb.org).  Editor, Steven Summerfelt, Ph.D.  Upcoming Events/AES Issues Forum and 7th International Conference on Recirculating Aquaculture.  Volume 10, Issue 3, Summer 2007.