International Council for the Exploration of the Sea, Charlottenlund Slot, 2920 Charlottenlund, Denmark

This paper not to be cited without prior reference to the Council *) t INTERNATIONAL COUNCIL FOR THE C.M. 1975/B: 3 EXPLORATION OF THE SEA Gear and Behaviour Committee. Ref. Fislieries Improvement Committee. REPORT OF THE AD HOC MEETING ON DESIGN AND PRACTICAL OPERATION OF RESEARCH AQUARIUM SYSTEMS, HELD AT TEXEL, THE NETHERLANDS, FROM 7 to 10 APRIL 1975. *) General Secretary, International Council for the Exploration of the Sea, Charlottenlund Slot, 2920 Charlottenlund, Denmark. This paper not to be cited without prior reference to the author. INTERNATIONAL COUNCIL FOR C.M.1975/B:3 THE EXPLORATION OF THE Gear and Behaviour Committee. SEA. Ref. Fisheries Improvement Committee. REPORT OF THE AD HOC MEETING ON DESIGN AND PRACTICAL OPERATION OF RESEARCH AQUARIUM SYSTEMS HELD AT THE MUSSEL EXPERIMENTAL STATION TEXEL, THE NETHERLANDS FROM APRIL 7TH - 10TH 1975. BY KIND INVI TATION OF MR. A.C. DRINKWAARD. ================================================================= This working group was convened as a result of resolution number C. Res. 1974/2: 8. which stated since there was a need to con sider the more fundamental aspects of research aquarium design and operation, particularly for fish behaviour studies and since this broader subject was important also for aquaculture, an ad hoc meeting should be convened at a time to be agreed, pre ferably at a place havins modernBquarium facilities Ce.g. TexeI, Netherlands), to discuss and recommend guidelines for the design and practical operation of research aquarium systems: Dr. S.J. de Groot convened the meeting with Mr. P. Anthony as rapporteur and with the following people in attendance: List of Participants Dr. H. Ackefors - Institute of Marine Research S- 45300 - Lysekil - Sweden. K. Albrechtsen - Danmarks Fiskeri og Havunder s~gelser Charlottenlund Slot 2920 Charlottenlund,Denmark. Mr. P. Anthony - Marine Laboratory P.O.B. 101 Victoria Rd Aberdeen. Scotland (U.K.) Dr. J.H.S. Blaxter - Dunstaffnage Marine Research , Laboratory P.O.B. 3, Oban, Argyll, Scotland (U.K.) Mr. J.W. de Blok - Netherlands lnst. of Sea Research Texel - the Netherlands. - 2 - - 2 - Mr. O. Cendrero - Instituto Espanol de Oceano grafia,Laboratorio Oceanografico o ,. Lealtad 13, 5 Santander Spain. Mr. K. Christensen - Milj~styrelsens Fiskerilab. Jaegersborg Alle 1 2920 Charlottenlund - Denmark Dr. J. Dahl - Danmarks Fiskeri - og Havunders~gelser Charlottenlund Slot 2920 Charlottenlund, Denmark. Mr. A.C. Drinkwaard - Mosselproefstation RIVO 't Horntje, TexeI, The Netherlands. Mr. D.G. Ellis - Research Development Directorate Halifax Laboratory, P.O.B. 429 Halifax, Nova Scotia, Canada Dr. Ir. F.H. Fockens - Technical University, Mekelweg 2, Delft The Netherlands. Dr. M. Fonds - Netherlands Inst. of Sea Research Texel - The Netherlands. Mr. F. de Graaf - Artis Aquarium Plantage Middenlaan 45 Amsterdam,The Netherlands. Dr. S.J. de Groot - Netherlands Inst. for '.Fishery Investigations P.O.B. 68, Ymuiden, The Netherlands. Mr. E. Hoffmann - Danmarks Fiskeri - og Havunderss~gelser Charlottenlund Slot, 2920 Charlottenlund Denmark. Dr. R. Kirk Ave de Mai, 257 1200 Bruxelles. Belgium. Dr. V. Labordus - Dept. of Zoology University of Utrecht Padualaan 8 - Utrecht The Netherlands. Mr. L. Noort - T.F.D.L. Mansholtlaan 12 Wageningen,The Netherlands. Dr. W.R. Penrose - Biological Station, 3 Water St., St. John's New Foundland - Canada, AlC 258. - 3 - Dr. P. Sorgeloos - Lab. Biologisch Onderzoek van Milieuverontreiniging Jozef Plateaustraat 22 B- 9000 Gent - Belgium. Mr. H. Talloen - Lab. Biologisch Onderzoek van Milieuverontreiniging Jozef Plateaustraat 22 B- 9000 Gent - Belgium. Mr. R. Van Thielen - Institut für Meereskunde Aquarium 23 Kiel Düsternbrookerweg - W. Germany. Dr. J.C. Wallace - Institute of Biology and Geology, University of Tromsö N- 9001 Tromsö P.O.B. 790 Norway. Dr. P. de Wilde - Netherlands Institute of Sea Research Texel - The Netherlands. Dr. M. Zahn - Löbbecke Museum und Aquarium 4 Düsseldorf 1 Postfach 1120, W. Germany The meeting continued with contributions as listed in appendix 1. Several subjects were put forward for special consideration by the meeting. 1. Dr. R. Kirk emphasised that the Commision of the Environmen tal Council of the EEC was looking for ways to help scien tists in EEC and other countries in the harmonisation of :sci~ntific programmes. He asked that the meeting should con- sider the merits of different ideas such as the EEC:- a) paying for the organisation of meetings; setting up a library of videotapes; circulating a newsletter. b) circulating lists of manufacturers of items of aquarium in terest c) preparing a multilanguage dictionary of terms used in ma rine science. 2. Dr. J. Wallace explained that Tromsö University have the problem of siting a new Marine Aquarium. The choice is be tween a facility on the site of an old marine station with access to good seawater and boats but 3 km from the Univer sity or a site in the University campus with a long'pipe line to the sea. After some discussion the meeting was re quested to vote on the alternatives and the vote was 19 to 2 in favour of staying close to the sea. Discussions then took place under the following headings: 1. Location of facilitiesjStrategy of design. The analogy was drawn between the design of research veoscls and aquaria and it was thought that consideration should be given to designing relativcly simple buildings with'a finite life. .4- - 4 - It was emphasised that there should always be the closest cooperation between architects: design engineers, builders and the future users if design faults are to be avoided. 2. Water Sources Careful comparison of costs should be made of the various methods of obtaining seawater such as by research vessels, tankers, pipelines or preparation of synthetic seawater. When a closed system is necessary one must calculate wether it is not cheaper to use artificial sea water. The materials are obtainable ready-mixed and are easy to prepare. Pipelines for open systems are expensive to install and maintain and obtaining water by tanker can also be expensive and time-consuming. By the time natural sea water has been pumped and stored the organic matter will have changed and its possible advantageous properties may have been lost. Artificial sea water has a predictable composition and with its use there is no danger of introducing pollutants from the sea. Artificial sea water can also bc seeded \..,i th micro orga nisms and treated with EDTA to improve itG quality. Experience from inland sea water aquaria shows that the more delicate in vertebrates will breed in such conditions. Interest was ex pressed in the method of obtaining pre-filtered sea water from under the seabed. (e.g. the sub-sand extraction system of Sea Water Supplies Ltd. Skegness, Lincolnshire, England. , '" .. .. 3. Water Quality. A. The relative merits of open versus closed systems are as shown below: Closed Cheaper More expensive No danger of spoiling Danger of spoiling Danger of pollution from open sea No danger of pollution from open sea No accumulation of metabolites Accumulation of metabolites Danger of fouling No danger of fouling Food from water No food in water Less stability Greater water stability Spread of disease unlikely Spread of disease likely The meeting concluded that a dual system was preferable especially where sedimentation tanks or other means of excluding fouling or ganisms could be included. Even with an open system there should be sufficient reservoir capacity to switch to a closed system in an emergency. B. Filtration ~lE~.:. The relative merits of dry trickling filters and wet sand filters were discussed; It was emphasised that a large surface are is required for biological filtration and therefore trickling fil ters have a much higher effective capacity especially when using such materials as anthracitc lavalite, and/er dead shell. .. !3 .. - 5 - Ideally filtration should be carried out in two stages - firstly mechanical and secondly biological. Area of filters. r Depending on stocking density and head of water available on effec tive wet filter could be expected to have a maximum filtering rate of 2 to 3 m3/m/hr. A dry trickling filter could be expected to achieve a higher rate. With an aerated filter the total filter volume need not exceed 10% of the volume of the stocked tankes) even at a high stocking density. Aeration of filters. It was stressed that aerobic conditions should be present through out the depth of a filter bed and that this condition can be best achieved by aeration of a wet filter bed or by use of a dry trick ling filter. Sand in a wet filter will tend to aggregate and so the paths for aeration will be reduced. It is therefore better to use a light non-clurrping material with a large internal surface area such as lavalite. ~~~~!~~~~~~~-~!_!~~~~~~~ The possibility for backflushing of a filter or the first in a series of filters should be included in any new system. C. Supersaturation and degassing. Supersatuation is most likely to occur by leakage in pump system or by warming. Degassing is best carried out by degassing towers, cascades or strong aeration. Accurate measurement of supersaturation is difficult and the use of a saturometer is recom mended. (see appendix 5). D. Effluent control. It was recognized that a problem can exist in controlling pol lutants and disease organisms in the effluent from experimental aquaria. 4. Volume of System / Turnover Rates. In closed systems the minimum ratio between volume of reservoir and holding tanks should be 4: 1 with a turnover rate of one tank volume per hour at normal stocking densities. 5. Materials and Coatings. Metals apart from cast iron should be avoided wherever possible, and all materials including plastics should be tested for toxi city especially with delicate invertcb~atbs. Re-inforced con crete should be sealed as a precaution against corrosion of the reinforcement.

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