{BROODSTOCK AND LARVAE NUTRITION IN GILTHEAD SEABREAM}
{EXCRETION OF JAPANESE FLOUNDER}
{JAPANESE FLOUNDER, FRY FED MICROBOUND DIET}
{CRUSTACEAN ECDYSTEROIDS AND JUVENOIDS}
{LIPID ACCUMULATION WITHIN OVARIES OF PENAEID SHRIMP}
{GROWTH OF A FRESHWATER GREEN ALGA AND A ROTIFER}
{AQUACULTURE ECOSYSTEMS COURSE}
{AQUACULTURAL DEVELOPMENT: SOCIAL DIMENSIONS}
{UKMBC'96}
{EUROPEAN CRUSTACEAN CONFERENCE}
{PHYTOPLANKTON CULTURE COURSE}
{AMERICAN FISHERIES SOCIETY LIST}
Dear Newsletter readers,
The initial problems in compiling and editing this electronic piece of literature are well past and over now. On a routine basis we're issuing our Newsletter the 1st and 15th of every month (except for extraordinary circumstances, as marriage of secretary, disease of editor, carnaval festivities...). Nearly the same day the information is also available at WWW. As not every transmission succeeds from the very first day, you might receive the NL a little bit later.
Time for some evaluation. So far, the backup that we received from our readers is rather limited. Nevertheless, we need your evaluation and suggestions. Therefore, without distributing a full questionnaire, I would appreciate some comments on the following topics :
* do you receive the NL regularly (initially there were quite some problems with doubtful email addresses) ?
* do you forward/distribute the NL to others in your institute/company or is it for your private use ?
* what about the contents : is it well balanced, too heterogeneous, not relevant, outdated etc. etc. ?
* the editing : too chaotic, satisfactory, etc. ?
* do you consult the WWW-version ?
I hope to give you an overview of your reactions in the issue of April 1st.
Another important point. In issue 3 of December 1st, Daniel Fegan, industry representative and vice chairman, opened a discussion on the role of the industry within the IWGL-group and the relationship between academic and industrial research. He formulated some interesting thoughts on this topic in order to open the platform. Up to now, he has received very little response on this issue (neither have we). If we want the IWGL not to degenerate into merely a group of people subscribing to an electronic NL, without any mutual communication or exchange of ideas, the discussion is open NOW. Formulate your thoughts via the newsletter or by email at fdaniel@ratree.psu.ac.th.
The editor.
You can find us under http://Artemia8/.
The password to get access to the Newsletter's contents is KALLISTO
______________________________________________________________
BROODSTOCK AND LARVAE NUTRITION IN GILTHEAD SEABREAM SPARUS AURATA - NEW FINDINGS ON ITS MODE OF INVOLVEMENT IN IMPROVING GROWTH, SURVIVAL AND SWIMBLADDER INFLATION
Tandler, A., M. Harel, W.M. Koven, S. Kolkovski-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):95-111
ABSTRACT:
Larvae growth and survival of gilthead seabream (Sparus aurata) can be improved through better understanding of their nutritional requirements. In the last decade or so, we dwelled mainly on the fatty acid requirements of seabream larvae. The n-3 highly unsaturated fatty acid (HUFA) requirements are age dependent, being 4 mg per g (DW) rotifer (Brachionus plicatilis) at stages up to 250 microgram DW (22 days of age). Beyond this size, the requirements increase dramatically to 29.8 mg per g (DW) Artemia nauplii, possibly because of the tripling of the Artemia lipid content. Supply of this level of n-3 HUFA in early larvae was associated with a growth acceleration of 250% as compared with a low dietary supply of 0.8 mg n-3 HUFA per g (DW) rotifer. Moreover, like other marine fish, seabream has a preference for docosahexaenoic acid (DHA) over eicosapentaenoic acid (EPA) for both growth and survival. Our studies on seabream eggs and larvae show that these essential fatty acids (EPA+DHA) are incorporated preferentially into polar lipids and particularly into phosphatidyl choline and phosphatidyl ethanolamine as part of the biomembrane.
In addition to optimizing larvae growth and survival via the larvae diet, these factors were further improved through broodstock nutrition. Larvae growth, survival and swimbladder inflation are directly affected by the composition of the diet of the broodstock. We found that both protein and lipid fractions in squid meal play an important role in improving the fecundity and egg quality. A dietary inclusion of 5 mg n-3 HUFA per g diet was associated with over 80% of the larvae having a functional swimbladder as compared with 55% in broodstock fed soy oil. A further increase to 15 mg n-3 HUFA per g diet was associated with a 30% increase in daily larvae growth. For the best response of seabream broodstock, a 49% balanced protein diet with 15 mg n-3 HUFA per g is required. Being a daily spawner, it takes no more than 15 days for seabream to fully respond to the dietary change in terms of egg composition and viability. The protein fraction of squid meal has a significant effect on the egg quality of gilthead seabream. This is because the amino acid composition of squid is similar to that of the seabream egg. The presence of a balanced composition of essential amino acids expressed itself in vitellogenin synthesis and selective uptake through receptor mediated endocytosis.
In conclusion, growth and survival of larvae are the key to future mass production of fish in mariculture. Only a combination of basic and practical research in both phases, of oocyte buildup and a larvae development, will insure it.
(National Center for Mariculture, IOLR, P.O.Box 1212, Eilat 88112, Israel)
______________________________________________________________
NITROGEN EXCRETION RATE OF JAPANESE FLOUNDER - A CRITERION FOR DESIGNING CLOSED RECIRCULATION CULTURE SYSTEMS
Kikuchi, K.-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):112-118
ABSTRACT:
The nitrogen excretion rate of juvenile (1.6 to 6.5 g), young (15 to 56 g) and immature Japanese flounder (163 to 575 g) was measured.
The ammonia and urea excretion rates of starved flounder decreased with growth and the ammonia excretion rates of juvenile fish varied more and were much higher than those of larger fish. Rates of ammonia excretion of fed fish were 2 to 3 times higher immediately after feeding than those of starved fish, reached a peak 3-6 hours after feeding, and then declined. On the other hand, the urea excretion rate peaked 6-12 or 12-24 hours from feeding. Daily rates of ammonia, urea and feces nitrogen excretion per unit weight of fed fish were much higher in smaller fish, however, the proportion of each substance to the consumed nitrogen was similar in all three development stages.
(Biology Department, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, Abiko, Chiba, 270-11, Japan)
______________________________________________________________
GROWTH, SURVIVAL AND VITALITY OF RED SEA BREAM, PAGRUS MAJOR, AND JAPANESE FLOUNDER, PARALICHTHYS OLIVACEUS, FRY FED MICROBOUND DIETS
Hayashi, M.-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):119-128
ABSTRACT:
Rearing experiments were conducted to replace live food (rotifers and brine shrimp) by microbound diets for mass-produced red sea bream, Pagrus major, and Japanese flounder, Paralichthys olivaceus fry. Four test diets, manufactured by feed companies as prototypes of commercial diets, were used in each experiment, and 67-88% of the live foods were replaced by the test diets.
In both species, all test diets promoted good survival rates after 30 days of rearing. The growth of fry fed test was comparable to that of fry fed solely live foods. Particularly, the survival rates after vitality tests were much higher in fry fed test diets than in those fed only live foods. The results clearly demonstrate that the test diets can successfully substitute live foods.
(Tsukuba Research Laboratory, Harima Chemicals, Inc., 5-9-3 Tokodai, Tsukuba, Ibaraki, 300-26 Japan)
______________________________________________________________
CRUSTACEAN ECDYSTEROIDS AND JUVENOIDS: CHEMISTRY AND PHYSIOLOGICAL ROLES IN TWO SPECIES OF PRAWN, MACROBRACHIUM ROSENBERGII AND PENAEUS JAPONICUS
Wilder, M.N., K. Aida-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):129-136
(Japan International Research Center for Agricultural Sciences, Ministry of Agriculture, Forestry and Fisheries, 1-2 Ohwashi, Tsukuba, Ibaraki 305, Japan)
______________________________________________________________
A REVIEW: DIETARY BENEFITS OF ALGAE AS AN ADDITIVE IN FISH FEED
Mustafa, M.G., H. Nakagawa-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):155-162
ABSTRACT:
Algae biomass has been tested as a protein source for fish diet. This paper reviews the results of nutritional studies on algae meal used as an additive in fish feed. Algae raised the growth rate and feed efficiency and improved physiological conditions such as protein assimilation, lipid metabolism, liver function, stress response and disease resistance. The carcass quality of cultured fish was also improved by using algae meal as a feed additive. Algae might be essential for efficacious utilization of nutrients in fish.
(Faculty of Applied Biological Science, Hiroshima University, Higashi-Hiroshima 724, Japan)
______________________________________________________________
A REVIEW: LISTONELLA ANGUILLARUM INFECTION IN AYU, PLECOGLOSSUS ALTIVELIS, AND ITS PREVENTION BY VACCINATION
Kawai, K., R. Kusuda-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):173-177
ABSTRACT:
Only one vaccine against vibriosis caused by Listonella anguillarum (formerly Vibrio anguillarum) in ayu, Plecoglossus altivelis, and rainbow trout, Oncorhynchus mykiss, is available in Japan. As vibriosis is one of the most serious diseases caused by a drug resistant bacteria, much effort has been made to develop a vaccine against this disease. Among the three different routes of administration tested (oral, spray and immersion), immersion vaccination was the best and established for practical uses. A commercially produced immersion vibriosis vaccine is used widely on ayu farms. Responses in immunized ayu have not yet been studied except for a few studies on oral and immersion immunization. The most probable mechanism of protection in the immunized fish is that attachment of the bacterium is inhibited by factors produced in the skin mucous. Lipopolysaccharide of the bacterium is a potent immunogenic substance and raises the protective response of immunized fish.
(Fish Disease Laboratory, Faculty of Agriculture, Kochi University, Nankoku, Kochi 783, Japan)
______________________________________________________________
LIPOPROTEINS AND LIPID ACCUMULATION WITHIN THE OVARIES OF PENAEID SHRIMP
Lubzens, E., M. Khayat, T. Ravid, B. Funkenstein, A. Tietz-1995
The Israeli Journal of Aquaculture-Bamidgeh 47(3-4):185-195
(Israel Oceanographic and Limnological Research, National Institute of Oceanography, P.O.Box 8030, Haifa 31080, Israel)
______________________________________________________________
COMPARISON OF THE GROWTH AND SURVIVAL OF LARVAL TURBOT IN THE ABSENCE OF CULTURABLE BACTERIA WITH THOSE IN THE PRESENCE OF VIBRIO ANGUILLARUM, VIBRIO ALGINOLYTICUS, OR A MARINE AEROMONAS SP.
Munro, P.D., A. Barbour, T.H. Birkbeck-1995
Applied and Environmental Microbiology 61(12):4425-4428
ABSTRACT:
Larval turbot (Scophthalmus maximus) were reared on rotifers (Brachionus plicatilis) in the absence of culturable bacteria for up to 14 days and exhibited growth and high rates of survival (>55% in five experiments). Low numbers of known bacteria were introduced into similar cultures by exposure of the rotifers to a suspension of bacteria prior to addition of rotifers to the larval cultures; Vibrio anguillarum 91079 caused a highly significant decrease (P<0.01) in the proportion of survivors in two separate trials. With an Aeromonas sp. previously isolated from a healthy batch of copepod-fed larvae, there was no significant difference in survival compared with control larvae, even though the density of bacteria in the water of larval cultures reached 10^7/ml. Bacteria colonized the gut of larvae exposed to Aeromonas-treated rotifers to levels similar to those in conventionally reared fish (>4x10^4 CFU per larva). Rearing of larvae in the presence of known bacteria provides a means of investigating the interaction of specific bacteria with turbot larvae and could provide a method for the selection of bacteria which may restrict the growth of opportunistic pathogens which would be harmful to turbot larvae.
(Division of Infection and Immunity, University of Glasgow, Glasgow G12 8QQ, Scotland, UK)
______________________________________________________________
EFFECT OF HUMAN EXCRETA ON THE GROWTH OF A FRESHWATER GREEN ALGA (CHLORELLA SP.) AND A ROTIFER (BRACHIONUS CALYCIFLORUS)
Dahril, T., M. Ahmad, S. Iizuka-1995
Asian Fisheries Science 8(1):41-46
ABSTRACT:
The effect of human excreta on the growth of Chlorella sp. and Brachionus calyciflorus was conducted in uni-specific and in two mixed cultures. The excreta were dried in sunlight, then put in 1 l wellwater and boiled for 2 h. The excreta were filtered. Five concentrations of human excreta (0.0, 0.5, 2.0, 3.5 and 5 g/l) were used.
The results of this study indicated that human excreta can promote the growth of Chlorella sp. The highest growth was found at 0.5 g/l of human excreta. However, the density of Chlorella sp. decreased 2 d after B. calyciflorus inoculation. Human excreta could not be used directly as feed of B. calyciflorus, but could promote the growth of Chlorella sp. as food of B. calyciflorus. The best growth of B. calyciflorus at the density of 109 ind/ml was at 0.5 g/l of human excreta.
(Faculty of Fisheries, University of Riau, Jl. Pattimura No.9, Pekanbaru, Riau, Indonesia)
______________________________________________________________
Letter from Bob Rosenberry, Editor/Publisher
I have terminated the bimonthly report Shrimp News International and will now work full-time on the directory and annual report.
Many factors contributed to this decision, but it was the drudgery of managing subscriptions in sixty countries that sealed the fate of Shrimp News. With the number of subscribers at an all time high and new subscriptions rolling in at record rates, I could no longer manage the business by myself, and I did not want to take on employees.
I am continuing to collect and edit information on shrimp, so please continue forwarding your letters, faxes, e-mails, reports, clippings, papers, announcements, offerings, notices and presentations. This information will be disseminated in the annual report and on the world wide web (free, if everything goes according to plan).
9434 Kearny Mesa Road, San Diego, CA 92126 USA
Phone 619-271-6354, Fax 619-271-0324, E-mail brosenberry@aol.com
______________________________________________________________
NEW TECHNIQUE BOOSTS MAHI-MAHI SURVIVAL
Research conducted at Hawaii's Oceanic Institute has led to a marked improvement in hatchery survival rates for mahi-mahi, (also known as dorado or dolphinfish) which are already popular on the US mainland and in Japan.
More than 40,000 fish have been produced from 128,000 eggs in a recent breakthrough at the Institute, achieving a 31 per cent survival rate. Previous rates were estimated at only about five per cent.
A new technique has been developed to enable mahi-mahi farmers to predict more certainly which spawns will produce the best larvae, although reasons for the variation in egg quality remain a mystery.
According to Dr Tony Ostrowski, head of the program, methods for screening eggs before hatching have so much improved that higher survival is assured.
"Commercial feasibility can now be demonstrated," said Dr Ostrowski. "Nevertheless there is room for improvement of grow-out procedures in a land-based ventury."
Production levels achieved at the Institute would be sufficient to supply a big mahi-mahi farm with an output target of 125 tons a year. This would take into account a loss of 50 per cent of juveniles during weaning from live to pelleted feed.
(excerpts from Fish Farming International, February 1996)
______________________________________________________________
FROZEN ZOOPLANKTON FOR FISH FRY DIETS
Frozen zooplankton for newly hatched or stressed larvae and fry is now available from British-based Aqua Company Ltd, which has worked closely with a leading producer of zooplankton and processor of its natural by-products.
According to the company's managing director Claire Stewart, the new product is 100 per cent pasteurised, preserved in its original body shape and colour, with its natural nutritional content and aroma.
"The micro crustaceans are made of up to 90-95 per cent Daphnia magna and 5-10 per cent Copepods," she explained.
"Free amino-acids are present in the frozen fluid that surrounds the zooplankton and these constitute a powerful attractant and appetite stimulant for fish, shrimp and other marine and freshwater invertebrates.
"Due to its moist content there is no danger of overfeeding. The product can be fed therefore until satiation is attained. chitin content has the same function as fibre in human diet and so will improve digestion and intestinal transit."
It is said to be suitable for culture of halibut, Arctic charr, salmon, shrimp, prawn, crayfish, and other species, including tropical fish, and can be used as a dietary supplement to more conventional dry feeds and to compound feeds such as extruded pellets. Recommended levels of incorporation before the extrusion process begins are 10 to 20 per cent by weight.
Aqua Company adds that the product can be used as feed for stressed or diseased fish which refuse other types of feeds.
"The condition of the fish is improved and mortality rates can be significantly reduced by feeding natural zooplankton as the sole or supplementary feed," said Claire Stewart.
Frozen and preserved at 18 C and packed in hermetically scaled tubes with an average weight of 2.75 to three kilos, the product must be used as soon as possible after thawing and must not be refrozen even after partial thawing.
Further information from Claire Stewart, Abbott House, 14a Hale Rd, Farnham, Surrey GU9 9QH, England, UK. Fax: (01252) 712308.
(excerpts from Fish Farming International, February 1996)
______________________________________________________________
INTERNATIONAL AQUACULTURE ECOSYSTEMS COURSE
Date: 25 Feb 1996
From: "Program in Aquaculture Ecosystems, Cal Poly Pomona"@atlas.cs.upei.ca
To: Multiple recipients of list <aqua-l@upei.ca>
Colleagues:
The Center for Regenerative Studies of California State Polytechnic University (Pomona, CA) is offering an international training course in "Aquaculture Ecosystems".
The course is an intensive hands-on training to acquire research and education in the development and management of integrated aquaculture-agriculture farming systems. Students will attend lectures, workshops and group discussions, and visit freshwater farms for tilapia, catfish, mussels and striped bass in Southern California. Special attention will be given to approaches in aquaculture farming systems diagnosis and analyses, participatory farming systems research and extension methods, and pond microbial ecology and chemistry for development of scientific aquaculture approaches.
The course will be held from 1 to 26 July 1996.
The comprehensive cost for the course is $2,500 which covers full tuition, room and board, books, and lab fees, plus three field trips, receptions, course text and reader, and certificate.
Course leader is Dr. Barry A. Costa-Pierce, Professor of Aquaculture and Coordinator of Research, Center for Regenerative Studies, California State Polytechnic University.
For more information, applications, brochures, etc. contact:
The Secretary, Program in Aquaculture Ecosystems, Center for Regenerative Studies, California State Polytechnic University, 4105 West Temple Avenue, Pomona, California 91768 USA Phone: 909-468-1705 or 468-3884; Fax: 909-468-1712 e-mail <aquaculture@csupomona.edu>
Course is limited to 30.
______________________________________________________________
AQUACULTURAL DEVELOPMENT: SOCIAL DIMENSIONS OF AN EMERGING INDUSTRY
Edited by Conner Bailey, Svein Jentoft and Peter Sinclair. Boulder, Colorado: Westview Press. 1996. US$49.85.
Contents:
Part One
Introduction
1. Social Science Contributions to Aquacultural Development
Conner Bailey, Svein Jentoft and Peter Sinclair
Part Two
Aquacultural Development in Industrialized Nations
2. The Sky Is The Limit? The Rise and Fall of Norwegian Salmon Aquaculture, 1970-1980
Petter Holm and Svein Jentoft
3. Norway's Cod Farming Industry: Adaptation, Imitation or Innovation?
Bernt Aarset and Lene Foss
4. Aquaculture in the Baltic Sea: Regional Development and Environmental Conflict
Erland Eklund
5. Along the Coast and in the State: Aquaculture Politics in Nova Scotia and New Brunswick
John Phyne
6. Paradise Under Siege: A Case of Study of Aquacultural Development in Nova Scotia
Ann Dwire
7. The Political and Social Context of Technology Transfer: Two Oyster Projects in Florida
Priscilla Weeks and Leslie Sturmer
8. Catfish in the Farming System of West Alabama
Karni Perez, Conner Bailey and Amy Waren
9. Colonizing the Coastal Frontier: Governing Marine Salmon Farming in Scotland
Jan Willem van der Schans
Part Three
Aquacultural Development in Non-Industrialized Nations
10. Shrimp Mariculture Development in Two Rural Mexican Communities
Mar=Ala L. Cruz Torres
11. Social and Environmental Impacts of Coastal Aquaculture in Indonesia
Chairul Muluk and Conner Bailey
12. Household and Community Factors Affecting Development of Small-Scale Fish Farming in Africa
Kenneth Ruddle
13. Institutional Requirements for Aquacultural Development in Africa: Lessons from Rwanda
John F. Moehl and Joseph J. Molnar
14. Cages, Controversies, and Conflict: Carp Culture in Lake Toba, Indonesia
Richard B. Pollnac and Saudara Sihombing
15. Fish, Pigs, Poultry, and Pandora's Box: Integrated Aquaculture and Human Influenza
Mike Skladany
______________________________________________________________
1st UK Maine Biotechnology Conference 1996
August 22-23 1996,
Departement of Biological Sciences
Heriot-Watt University, Edinburgh, UK
This International meeting, sponsored by the Royal Society of Chemistry (Biotechnology Group) will deal with recent advances in marine biotechnology with sessions on;
Biotechnology and the Fishing Industry
New Industrial Materials and Processes from Marine Algae and Bacteria
Chemical Diversity of Marine Natural Products
Marine Biotechnology, an International Perspective
For further information please contact the conference chairman
Dr J.G. Burgess
Department of Biological Sciences
Heriot-Watt University
Riccarton, Edinburgh EH14 4AS, UK
Tel: +44-131-451-3463
Fax: +44-131-451-3009
e-mail: bbsjgb@bonaly.hw.ac.uk
www: http://www.bio.hw.ac.uk/biotec/biotec.htm
______________________________________________________________
2nd EUROPEAN CRUSTACEAN CONFERENCE,
LIEGE (BELGIUM)
September 2-6, 1996
hosting
the 7th MEETING OF THE GEREC
the 2nd INTERNATIONAL WORKSHOP ON MAJID CRABS
the CRUSTACEAN LARVAL CONFERENCE
and an ESCPB SPECIALISED SYMPOSIUM
Address for correspondence
2nd European Crustacean Conference
General Secretariat
Quai Van Beneden 22 B-4020 Liege (Belgium)
Phone: +32-41.66.50.46 +32-41.66.50.72
+32-41.66.50.62 +32-41.66.50.98
Fax: +32-41.66.50.10 +32-41.66.50.20
A. Main Topic Sessions
Session I: Phylogeny - Palaeontology - Systematic Morphology and Evolution
Session II: Morphology
Session III: Ecology - Ecotoxicology
Session IV: Ion transport - cellular and molecular mechanisms. An ESCPB Specialised Symposium
Session V: Physiology of Endocrinology
Session VI: Metabolism and Nutrition
Session VII: Immunity and Diseases
Session VIII: Aquaculture and Fisheries:
Scientific Organiser: Aiken D. (St Andrews, New Brunswick, Canada).
Invited Speakers: Names of invited speakers and titles of lectures to be communicated in the second
announcement.
Session IX: Reproduction and Development: see Larval Conference
B. Crustacean Larval Conference
__________________________________________________________
INFOFISH-AQUATECH 96 and AQUACULTURE ASIA 96
25-28 September 1996
Kuala Lumpur, Malaysia
INFOFISH, in collaboration with Emap Heighway, UK, is staging this double event - international conference and exhibition on aquaculture.
INFOFISH-AQUATECH'96. The third in a series of international conference on aquaculture organised by INFOFISH, will focus on the latest developments in world aquaculture and its technical and economic outlook for the future.
AQUACULTURE ASIA'96 exhibition will feature the latest equipment, technology, feeds and services for the booming aquaculture business. With world aquaculture on course to produce over 30 million tonnes by the year 2000, there is a huge world-wide demand for equipment, technology and feeds, which will help achieve this target.
For information, contact INFOFISH, P.O.Box 10899, 50728 Kuala Lumpur, Malaysia.
Tel: (603)2914466
Fax: (603)2916804
E-mail: infish@pc.jaring.my
______________________________________________________________
Date:5 Mar 1996
From: Howard Dryden <100550.3100@compuserve.com>
To: Multiple recipients of list <aqua-l@upei.ca>
COMMENTS 1:
We have constructed some quite large protein skimmers measuring up to 2 metres
in diameter and 5 metres high. The units used venturi high pressure injection
systems and were coupled with ozone generators.
The equipment was used for foam fractionation of water and for ozonation, the
system will not remove ammonium directly from solution nor will the ozone
oxidise the ammonium. Fractionation also works best whenever the salinity of
the water is greater than about 17ppt, therefore it is not ideally suited to
freshwater applications.
The limitations are that if you inject air through the venturi you cause gas
supersaturation with nitrogen. This water will then cause gas embolism among
the fish unless it is degassed or if the fish are held in deep tanks such as
aquarium ocean systems. The second limitation is that if you exceed an ozone
dose rate of 0.1 to 0.3mg/l you will probably get white foam and a pure
utilisation of the ozone.
Protein skimmers can also strip out cations from the water, therefore aquariums
or marine recycle systems can have basic water chemistry problems.
On a positive note, protein skimmers can remove a tremendous amount of organic
matter from recycled water. However you should ask the question... Why is the
organic matter there in the first place... ?. The feed given to the fish must
be stable, and you should not over feed. The tanks must be self cleaning and
all fish faecal matter and feed must be removed from the water immediately it
exits the tank. If you wish to operate intensive high density systems then
conventional, tanks, filters or sedimentation tanks are not suitable.
If the above hygiene and solids removal conditions are satisfied you will
dramatically reduce the organic and protein loading on the system and there will
be no requirement for protein skimming. However there will still be a
requirement for ozonation. This task is best satisfied using counter-current
contactors operating under slight negative pressure. You can achieve
concentration up to 4mg/l of ozone in solution without any loss. This also
means you need only treat a small side stream of between 10% and 25% of the
total water flow and mix the highly ozonated water back into the main flow. The
system is simple, stable and you avoid all the problems encountered with protein
skimmers.
Regards
Howard T Dryden
Dryden Aquaculture
Butlerfield
Bonnyrigg
Edinburgh EH19 3JQ
Scotland
Tel (44) 18758 22222
Fax (44) 1875822229
COMMENTS 2:
Protein skimmers are not an effective measure for the removal of
ammonia as the theory of protein skimmers relies on the adsorption of
surface active molecules onto an air bubble. As such, protein skimming
(or foam fractionation) is suitable for long chain molecules with both a
hydrophobic and hydrophilic end, such as dissolved organics and proteins,
but not suitable for the removal of small molecules such as
ammonia.
The use of ozone within the protein skimmer is effective in
oxidizing long chain molecules into smaller molecules. The degree to
which ammonia is oxidized is however very small, due to a number of
factors. The first factor is that ammonia concentrations in aquaculture
systems are very low (or should be!). As such the chances of contact
between ammonia and the short lived ozone molecule (or O radical) is quite
low, most ozone will have reacted with more common species before an
encounter with ammonia occurs.
In addition to this is the fact that only the ammonia molecule can be
oxidised (not the NH4+ ion). In the temperature and pH ranges
characteristic of aquaculture systems only a small percentage of total
ammonia is present as the ammonia molecule, thus decreasing the chance of
an ozone-ammonia encounter even further.
The use of ozone in seawater does carry with it the chance of
oxidising elements such as bromide into toxic acids such as hydrobromous
acid. These potential hazards have not yet been quantified and
do not appear to have curbed the use of ozone in salt water systems.
Gavin Partridge.
COMMENTS 3:
Just a thought on the use of protein skimmers to remove ammonia:
My understanding is that ammonia (NH3) off-gasses relatively rapidly.
Protein skimmers may assist this process by providing a large air-water
interface contact area and substantial water turbulence that would help
dissipate NH3. Of course, you may need a large skimmer on a small volume
system to make a significant impact.
Mike Rimmer Email: michaelr@qdpit.sth.dpi.qld.gov.au
Finfish Aquaculture Research Group or: rimmerm@dpi.qld.gov.au
Northern Fisheries Centre Phone: +61-070-529809
Cairns, Queensland, Australia Fax: +61-070-351401
COMMENTS 4:
My understanding is that while mechanical filtering can remove suspended solids
(SS) down to 30 to 60 microns, one needs a foam fractioner/protein skimmer (am
I correct in assuming that they are the same thing?) to get SS smaller than
that.
So if a system did not have a protein skimmer, then the small particles <30
microns would travel through the system until:
a) they settle out or merge into bigger particles that are removed or
b) they are digested by bacteria with a byproduct of this digestion being
ammonia.
My question is this. Is this ammonia from option B, significant, and would
removing the SS (and eliminating the future production of ammonia ) with the
foam fractioner decrease the load on the biofilter, allowing for a smaller
biofilter, or does the foam fractioner merely reduce the turbidity in the water
and do very little else for water quality.
Evan Mead
_____________________________________________________________
Date:5 Mar 1996
From: Somchai Ponlasit <somchai@ait.ac.th>
To: Multiple recipients of list <aqua-l@upei.ca>
You are all welcome to visit us at our homepage to know more about the
Aquaculture program at the Asian Institute of Technology, Thailand.
URL - http://www.ait.ac.th/AIT/aqua/
Arlene S.
Aquaculture Short Course Unit
_____________________________________________________________
Date:8 Mar 1996
From: Tom Lewis <T.Lewis@agsci.utas.edu.au>
To: Multiple recipients of list <aqua-l@upei.ca>
Just a quick note to those who may be interested in the upcoming Australian
Marine Sciences Association 1996 conference, to be held at the University of
Tasmania in Hobart, Tasmania between 10 - 13 July 1996.
Information about this conference can be found via the WWW at
http://www.utas.edu.au/docs/agsci/AMSA96/amsa_'96.html.
Tom Lewis
Department of Agricultural Science
University of Tasmania
GPO Box 252C
HOBART, Tasmania 7001
AUSTRALIA
phone (002) 20 2776 fax (002) 20 2642
o'seas (+ 61 02) etc
______________________________________________________________
Date:4 Mar 1996
From: Dirk Miller <dmiller@wyoming.com>
To: Multiple recipients of list <aqua-l@upei.ca>
Fishing for Information Home Page: Guide to online resources in aquaculture,
fisheries and aquatic science.
http://www.stir.ac.uk/aqua/fishing/
Dirk Miller
dmiller@wyoming.com
Fish Population Supervisor, Wyoming Game and Fish Department
President, American Fisheries Society Computer User Section
528 S. Adams St.
Laramie, WY 82070
Voice (307) 742-6007 -- FAX (307) 742-6408
AFS Home Page
http://www.esd.ornl.gov/AFS
____________________________________________________________
Date: 1 Mar 1996
From: Field, Becky <BFIELD@Kilcom1.UCIS.Dal.Ca>
To: Multiple recipients of list <aqua-l@upei.cA>
The Aquaculture Association of Canada has over the years
recognized that students are an important and integral part of
the Annual Meeting. Students are the future of the Association
and their participation ensures that highly trained and motivated
personnel are available at all levels of the aquaculture
community. As a way of promoting student participation at the
13th Annual Meeting in Ottawa, Ontario, the AAC is pleased to
announce that both Travel and Presentation awards will be
available to students. (see next message for more information on
Aquaculture Canada'96)
For further information or to apply for the Student Travel
Awards, please contact:
Christine Hodgson
AAC Board of Directors Vice President (Awards)
Ministry of Agriculture, Fisheries and Food
2500 Cliffe Ave.
Courtenay, BC V9N 5M6
Phone: 604-334-1408
FAX: 604-334-1410
email: chodgson@galaxy.gov.bc.ca
___________________________________________________________
13th Annual Meeting of the Aquaculture Association of Canada
June 2-5, 1996 - Holiday Inn, Byward Market - Ottawa, Ontario
The Annual Meeting of the Aquaculture Association of Canada is an
opportunity for researchers, growers, suppliers and students to
get together to discuss the latest technologies and research in
aquaculture. The theme of Aquaculture Canada '96 is
"Diversification" to encompass the latest trends in the
industry. Special sessions and sessions for submitted abstracts
are planned which will include the most recent information on:
* Urchin Culture & Enhancement
* Government Industry Relations
* Human Resource Issues
* Bottlenecks in Juvenile Production
* Water Quality
* Marketing
* Federal Aquaculture Strategy Review
* Regulatory Issues
* Therapeutants
* Development in Shellfish, Salmonid and Marine Fish Culture
* Engineering
April 1, 1996 is the abstract deadline for contributed oral and
poster presentations. For more information, contact:
Aquaculture Association of Canada Office
P.O.Box 1987
St. Andrew's, NB Canada E0G 2X0
Telephone: 506-529-4766
FAX: 506-529-4274
email: aac@wolves.sta.dfo.ca
Becky Field
Coastal Resources Research Network
ISLE Secretariat
email - becky.field@dal.ca
Lester Pearson International Institute
Dalhousie University
1321 Edward Street
Halifax, NS B3H 3H5 Canada
phone 902-494-1842
FAX 902-494-1216
___________________________________________________________
Date: 29 Feb 1996
From: Stephen Walker <102002.2214@compuserve.com>
To: Multiple recipients of list <aqua-l@upei.ca>
Will someone please post a brief description of the term "green water"?.
George Eastwood
Wastewater Technology Centre
Burlington, Ontario, Canada
george.eastwood@cciw.ca
COMMENTS 1:
"Green water" is also called "background photoplankton" and is an addition of
unicellular algae to the larvae rearing system. Many researchers refer to the
use of green water in their culture systems and laud its advantages. Most claim
(without reference) to the "conditioning" of the water by the algae "probably
by removing harmful metabolites of the larvae." Later work has shown that this
is probably not why green water works. It is more likely that the green water
enhances the nutrition of live food in the tank. Also there may be a behavioral
aspect as larvae begin to rely on other than strictly visual cues to find their
food, or they may avoid tank walls more in the green water tank.
An excellent article on the subject is:
"The paradox of using background phytoplankton during the larval culture of
striped mullet, Mugil cephalus" AQUACULTURE 119 (1994) 167-174. Clyde S.
Tamaru, et al.
Stephen Walker
Curator of Aquaria
Tulsa Zoological Park
(918) 669-6249
102002.2214@Compuserve.com
COMMENTS 2:
Green water: water that turns green due to the presence of plankton, specifically phytoplankton, resulting from the addition of fertilizer and other organic matter. This system is suitable for filter feeders esp. tilapia.
Arlene S.
Programme Specialist
Asian Institute of Technology.
COMMENTS 3:
In the culture of marine fish larvae us seabream -Sparus aurata- we join microalgae (i.e. Nannocloropsis sp.) to the thanks, during the first 20-30 days, in order to maintain the rotifer feed and it seems to be beneficial to the water quality and to the ability to the larvae to find the preys. The water renewal is low (i.e. 50-100% day) and the quantity of algae is about 1-2%.
>
ppousao @mail.telepac.pt
COMMENTS 4:
Green water is used as a primer in various flatfish aquaculture operations,
particularly for winter flounder and halibut here in Southern New Brunswick,
Canada.
We use mono- and polyculture supplementation favouring Isochrysis in each of
them. You can get various starter kits from "algae banks" akin to how a
horticulturalist might get seeds from a seed bank.
The idea is that larval fish naturally develop in an environment with the
algae. Greening the water may help larval fish in seeing their food as well
as fortifying or improving the nutritional value of live feed (such as
rotifers or artemia (brine shrimp)). Some fish won't eat without it.
Since a lot of fish raising here involves flow through systems as opposed to
recirculation or static systems, "allowing" a natural bloom to occur isn't
feasible without green water supplementation.
Jonathan Trifts
jtrifts@nbnet.nb.ca
COMMENTS 5:
For the last 8 years we are pumping algae and rotifers around the hatchery
- several tons of water per day. We use pneumatics pumps and the system
is extremely reliable and cheap, just few thousands of us$ for our hatchery
that can produce 4+ millions fish fry in a year. Algae are pumped into the
rotifers tanks, rotifers enrichment tanks and larval tanks (twice day) =
"green water" culture method as we call it around the mediterranean sea.
Rotifers are pumped from the culture tanks to the concentrating tanks, to
the enrichment tank, to the feeding tank and to the larval tanks. We also
pump Artemia nauplii from hatching tanks to enrichment tanks and after the
enrichment to a feeding tanks. No damaged is caused to the live food also
the length of the pipes is more than 50m and air pressure is 2-4 Atm.
We are feeding nauplii by hand just because we are feeding it according to
the needs of A fish tank and it helps us to feel what is happening with the
fish.
Yoav Barr
ARDAG, Red Sea Mariculture, P.O. B. 1742, Eilat 88116, Israel. phone
+972 7 335111, fax +972 7 377901 e-mail: ybarr@shani.net
Date: 03/04/96
Time: 13:47:17
COMMENTS 6:
Green water is basically a algal soup mix where the algae is the feed stock for plankton, rotifers and even filter feeding fish like Tialpia.
Recent studies have been conducted which indicate that specific larval species,
usually within the first week of hatching, have genetic imprints of what is
"food" and what is not. That is, they recognize only very specific plankton as
"their food" and may even starve to death in a very rich green water soup if the
specific species is not present.
The soup mix thus needs to be species specific. This means that both the algae
and plankton species must be compatible and these must suit the larval species.
Tom Kramer
COMMENTS 7:
I have done some work with growth rates of Euphausiids in a "soup" of
Thalassiosira. The algae were too small by an order of magnitude to be
effectively taken by the Euphausiids, therefore there was no demonstrable
transfer of biomass from the soup to the crustaceans. An intermediate
organism such as a copepod species when added to the culture effectively
bridged the size gap and the primary production of the Thalassiosira was
transferred to the Euphausiids with normal conversion losses.
James Clinton
CIMS Implementation Technician
DOH
CFH 7880
Airdustrial Park
Olympia, WA 98504, USA
(360) 664-9228
jdc2303@hub.doh.wa.gov
_____________________________________________________________
THE NATIONAL SHELLFISHERIES ASSOCIATION
Date: 26 feb 1996
From: David Bushek <dbushek@belle.baruch.sc.edu>
To: Multiple recipients of list <aqua-1@upei.ca>
The National Shellfisheries Association (NSA) is an international organization of scientists, management official and members of industry that is deeply concerned and dedicated to the formulation of ideas and promotion of knowledge pertinent to the biology, ecology, production, economics and management of shellfish resources. The Association has a membership of more than 1000 from all parts of the USA, Canada, and 18 other nations; the Association strongly encourages graduate student membership and participation..
WHAT DOES IT DO?
- Sponsors an annual scientific conference.
- Published the peer-reviewed Journal of Shellfish Research.
- Produces a Quarterly Newsletter.
- Interacts with other associations and industry.
For subscription, contact Christine Hodgson, BC Ministry of Ag. and fisheries, 2500 Cliffe Avenue, Courtenay, British Colombia, CANADA V9R 5M6.
_____________________________________________________________
MARINET PHYTOPLANKTON CULTURE TECHNIQUES COURSE
Date:25 Feb 96
From: Andersen@CCMP.bigelow.org
To: shellfish@kenyon.edu
Cc: andersen@CCMP.bigelow.org
The Provasoli-Guillard National Center for Culture of Marine
Phytoplankton, Bigelow Laboratory for Ocean Sciences, will be offering an
intensive one week course on Culture Techniques. The course will be taught by
Dr. Robert R.L. Guillard and Dr. Robert A. Andersen. The practical course will
include methods for establishing or manipulating cultures of research and
aquaculture. Isolation methods will include enrichments, direct isolation by
micropipette, agar plating, isolation by phototaxis, and dilution protocols.
Purification of cultures will include antibiotic treatments, "washing" and
combinations of these and other methods. Culture media will be described,
including the composition, preparation, and sterilization of media as well as
development of new media for specific situations. Physical factors such as
light, temperature, salinity and aeration will be described. Mass culturing
will be discussed, including batch, pulsed and continous culture methods. A
brief discussion of algal systematics will be presented, including a survey of
living representatives from classes containing marine phytoplankton. The
minimum number of students will be 10 and the maximum number will be 12. For
participants interested in obtaining college credit, the University of New
England will provide one credit hour for the course (no additional cost).
The course will begin on Monday morning, May 13, at 8:30 AM and will
continue until Friday afternoon, May 17.
Tuition plus housing is $1000. A deposit of $300 dollars will be
required; the deposit is refundable until April 10. The balance of the payment
is required by May 10.
To register for the course or for further information, please contact
Robert A. Andersen at the following email address: andersen@ccmp.bigelow.org (or
reply to this message). In case of more than 12 inquiries, participants will be
chosen based upon the earliest dates on which they provide a firm verbal or
written commitment (followed by receipt of their deposit). For further
information about the CCMP, see our Home Page: http://ccmp.bigelow.org/
Robert A. Andersen
Director, Provasoli-Guillard National Center for Culture of Marine Phytoplankton
phone: 207-633-9632
fax: 207-633-9641
email: andersen@ccmp.bigelow.org
____________________________________________________________
AFS-L AMERICAN FISHERIES SOCIETY LIST
Date:21 Feb 1996
From: Dirk Miller <dmiller@wyoming.com>
To: Multiple recipients of list <aqua-l@upei.ca>
Description: The AFS list is a general discussion list just formed
for AFS members. Timely news items including job postings,
legislative activities, meeting announcements, calls for papers
and other general interest news items are posted. It is hoped that
it will envolve into a discussion forum for discussion of general
fishery management, fish culture and fishery science issues as
membership grows.
Membership: Restricted to AFS members
Messages: Unmoderated
Subscription address: majordomo@wyoming.com
Subscription message: SUBSCRIBE AFS-L YourEmailAddress
Contact person/address: Dirk Miller dmiller@wyoming.com
Dirk Miller
dmiller@wyoming.com
Fish Population Supervisor, Wyoming Game and Fish Department
President, American Fisheries Society Computer User Section
528 S. Adams St.
Laramie, WY 82070
Voice (307) 742-6007 -- FAX (307) 742-6408
_____________________________________________________________
Date:15 Feb 1996
From: John G. Woiwode <103326.2316@compuserve.com>
To: Multiple recipients of list <aqua-l@upei.ca>
We have designed, constructed and operated a zeolite "biofilter" in a
recirculating system for a large-scale, commercial prototype aquaculture
facility. The zeolite was housed in parallel fluidized beds, with one bed in
operation while the other was recharging and/or standing by. The recirculation
pathway was designed as a back-up for the volume of the 27 raceway multipass
open system, in case of power plant failure or offending water quality (6 alarm
states). Alarm states were frequent; and in operation, the system worked
flawlessly.
Recharge is a straightforward process of required bed-volumes per hour at a
defined concentration. One has to address the question of where the brine, now
with ammonium chloride, will be discharged; this can be a significant issue.
Dr. Dryden's comments regarding the recharge are true, as the zeolite tends to
be non-discriminating for cations, and actually preferential for divalent
cations. However, in the recharge procedure, we forced virtually all of the
receptor sites to accept a Na ion by the high concentration of the recharge
solution. We thus never experienced a deterioration in the performance of the
zeolite.
His comments regarding the zeolite becoming a biofilter are a point to consider
as well; one does not necessarily want to design zeolite as the media for a
fluidized bed biofilter, as this adds another variable to a dynamic process that
a biofilter design process attempts to make predictable and stable. Instead,
use coarse sand for biofilter media in a fluidized bed; use zeolite when you
want predictable, instantaneous ammonia removal.
If you would like further information on our zeolite operations and recharge
rate, you may e-mail to me direct.
Dr. John G. Woiwode
AquaMatrix International, Inc.
___________________________________________________________
BACTERIAL NITRIFICATION IN RECIRCULATING SYSTEMS
Date:14 Feb 1996
From: ermira@pl.jaring.my
To: Multiple recipients of list <aqua-l@upei.ca>
The most critical factor is the ammonia and nitrite levels present in the
culture water. This is controlled in the biofilter by the aerobic and anaerobic
bacteria cultures. The aerobic (needs oxygen) bacteria, nitrosomonas and
nitrobacter, convert the ammonia (fish piss) NH4 to nitrite (NO2) and then to
nitrate (NO3) as the main operation of biofiltration. Note small amounts of
ammonia and nitrite can be highly poisonous to fish, but nitrate is harmless
even in high concentrations.
The problem in most recircualting systems is that the nitrate concentration
continue to rise and a reverse nitrate to nitrite reaction occurs...causing
disaster. It is thus necessary to remove some of the nitrates regularly. this
is usually done through water exchanges, or as I prefer, through hydroponic
filters (plants in shallow troughs). A third method is to introduce an
anaerobic (no oxygen) digester to the biofiltration system.
Anaerobic digesters are populated by pseudomonas bacteria which convert the
nitrates to nitrogen gas and carbon dioxide and as a result require a
re-aeration before re-entry to the culture system. This loop also requires a
organic carbon source which is most frequently supplied by dripping ethanol into
the incoming flow. The amount determines the activity of this filter and the
amount of nitrates in the whole system. Also, as this is an anaerobic system,
an oxygen sparge is necessary on the inflow. This can be done with nitrogen gas
bubbled into a inflow column.
Care must also be taken in the design of these biofilters as bacterial sludge
build-up will trigger the pseudomonas bacteria to produce hydrogen sulfide gas
(which is also highly poisonous). Sludge removal is thus very important. Suck
it off regularly, dry it a bit and then grow worms in it together with feed
fines...feed the worms to the fish and the casings are used for organic farming!
Don't worry about the heterotropic bacteria. Their job is to break down the
organic matter, waste food, etc. They get their organic carbon from these
sources. The addition of carbonates are primarily to balance the pH so that the
fish, plants and bacteria survive at optimal conditions.
Things still work regardless if the biofilters work properly. I have been
running acid rainwater fed systems with "no" water exchange for 5-years and with
only occassional fistfulls of lime added. I've had no major crashes at
densities of 50-75 kgs/m3 poly-culturing 6 commercial species together in the
same tanks with attached hydroponic units. About 1/3 of the water is in the
biofilter and hydroponic portion, but this would have to be increased if
densities were increased (to perhaps 2/3's water volume) plus sterilization
after biofiltration using ozone or UV. I'm working with greenwater systems so I
don't have that extra cost. I use shallow tanks, single pumps and a cascading
effect from biofilter chambers to hydroponics then back to tanks. Falls provide
all the aeration. NO oxygen used at all. No filters just sedimentation tanks
with sludge drains to the organic gardens. and everything works fine.
If you have further design problems just e-mail or write to me:
Thomas C. Kramer
Ak-mal Holdings Sdn Bhd
(Akuakultur Malaysia)
13A Jalan Gombak 5 3/4mi.
Gombak Setia, 53100 Kuala Lumpur
Malaysia
____________________________________________________________
{#LJz1#HOME}