by
K. Tiews1)
National Correspondent
I FISHERY BIOLOGY AND MANAGEMENT
The re-introduction experiments with the lake trout in the Lake Schlier, Bavaria, were continued at the experimental station Wielenbach of the Bayerische Landesanstalt für Wasserforschung, as well as studies to maintain the Bavarian population of Hucho hucho. Studies on the biological settlement of substrate in the river Main were carried out at the Bundesanstalt für Gewässerkunde in Koblenz. Species composition and abundance depend on the corn size and stability of the sediment. The fish populations of the lower Elbe and the available food basis for them was studied at the Institut für Meereskunde of the University of Kiel. Several fishery biological and ecological studies in lakes and rivers of northern Germany were carried out at the Institut für Hydrobiologie und Fischereiwissenschaft of the University of Hamburg.
Stock assessment work in the Lake Constance was continued at the Institut für Seenforschung und Fischereiwesen of the Landesanstalt für Umweltschutz Baden-Württemberg in Langenargen. The size of stock of coregonids in the Lake Constance in autumn 1983 was estimated by conventional methods to have been about 7 million specimen which is nearly three times higher as a previous stock estimate carried out by an international EIFAC experiment during the same year. Contrary to previous findings the stock of coregonids does not seem to be a sensitive indicator for changes of nutrients in the lake. Stock assessment work included also perch, eel and chars. The stock of Salvelinus profundus is expanding on the cost of the local species of char, Salvelinus alpinus. The eel stock in the Lake Constance feeds at present primarily on small perches instead of on a cyprinid species as previously.
Fishery biological studies on the fish stocks of several Bavarian lakes were carried out at the Bayerische Landesanstalt für Fischerei. These included echosurveys in combination with experimental fishing to study the horizontal and vertical distribution patterns of pelagic fish species. The Institut für Fangtechnik of the Bundesforschungsanstalt für Fischerei participated in the international EIFAC experiment in the Lake Tegel, West Berlin. Also comparative fishing experiments with monofile and multi-monofile yarns for gillnets were continued, as was the standardization of netting yarns, netting and ropes. The Institut für Küsten- und Binnenfischerei of the Bundesforschungsanstalt für Fischerei completed its work on the development of electrical fish barriers. After Dr. Halsband retired, this work shall not be continued at the institute.
II FISH CULTURE AND DISEASES
The warmwater experimental station of the Institut für Küsten- und Binnenfischerei of the Bundesforschungsanstalt für Fischerei in Emden which was established to develop commercial eel farming in the heated water effluent of the Emden conventional power station has been transferred to a private enterprise, after it has completed its research task. The commercial enterprise works now with economic success. Feeding experiments with carp fry and young carps were continued at the same institute in its Ahrensburg station. Studies to assess the optimal rearing temperature for carp fry demonstrated a growth increase with increasing temperature and a growth decrease when temperature exceeds 27°C. There was no relationship between growth and the duration of illumination. In rearing experiments with the European catfish (Silurus glanis) the growth of the animals was better in cylindric containers than in rectangular ones. Studies on the influence of the day length and the growth of the catfish showed that the fish grows best in the dark and worse at permanent light. Optimal stocking densities for catfish of 400 g was obtained when the fish was kept single, respectively was kept at a stocking density of 50 specimen per m3. If permanently kept at water temperatures of 24 – 27°C, the European catfish becomes mature at a weight of 1 – 1.5 kg. A weight of 5 g was reached after 9 weeks, of 10 g after 3 months, of 100 g after 6 months, of 1000 g after 10 – 11 months. Work on the controlled reproduction of the European catfish was continued, also on the mass rearing of fry. In cooperation with Israel a highly purified hypophysis extract was developed which yielded in 31 of 32 cases spawning success in comparison to 16 of 22 cases when normal carp pituitaries were used.
The Bayerische Landesanstalt für Fischerei in Starnberg continued its work on the testing of a recirculation system with trickling filters which proved to be not profitable for the production of consumption-sized fish. Furthermore the technical and hygenic risks are high. A method for the controlled reproduction of tench, applying hypophysation and stripping respectively offering artificial spawning substrate seems to be now ready for use in practice. The production of fingerlings and spawners of indigenous stocks of lake trout and lake chars was continued. The institute continued also its work on the development of rearing methods for coregonid fry in illuminated underwater net cages kept in lakes as well as on the reproduction of endangered fish species. Also work on the development of carp feeds using various plant proteins was continued.
Work on the optimation of trout feeds were continued at the Institut für Seenforschung und Fischereiwesen of the Landesanstalt für Umweltschutz Baden-Württember in Langenargen. The main aim was the reduction of the share of phosphorus in the trout feed, in order to improve the water quality in the ponds. Feed development work included also coregonids, pike and tench. Experimental studies on tropical pond fisheries in Peru were carried out at the Institut für Meereskunde of the University of Kiel especially with regard to develop waste fed aquaculture, fish cum swine. Also studies to optimize the transport of small fish in closed containers were carried out.
The Staatliche Fisch-Seuchenbekämpfungsdienst Niedersachsen has had its 10 years' anniversary in 1986. In these 10 years 5500 examinations of fish stocks in Niedersachsen and neighbouring states of the Federal Republic of Germany were carried out. During this period 10 cases of VHS, 1 case of IPN, 18 cases of ERM, 14 cases of furunculosis, 5 cases of erythrodermatitis, 1 case of BND and 2 cases of Edwardsiellosis were detected. One has to assume a dark figure of about 30 – 70 %. In view of the increase of the redmouth disease (ERM) the vaccination program of rainbow trout stock was continued. Experimental studies included infection trials on rainbow trouts with the virus of VHS. Incubation time increases with the age of the fish and the lower the temperature is. Mortality rates were highest at temperatures of about 4°C. Other studies concern the swimbladder inflammation of the carp, the sphaerosporosis of the tench, the infection of carp fry with Sanguinicola sp., Branchiomyces, Sphaerospora Coccidia, as well as Cercaria of Bucephalus.
The Institut für Zoologie und Hydrobiologie of the Tierärztlichen Fakultät of the University of München concentrated on the study of the bacterial kidney disease, BKD, of the salmonids and with the problem of acidification of inland waters and its effect on the fish fauna. Diagnostic and therapeutic studies concerned VHS, IPN and SVC.
The Institut für Küsten- und Binnenfischerei of the Bundesforschungsanstalt für Fischerei studied in cooperation with the Landesanstalt für Fischerei Nordrhein-Westfalen in Albaum the development of nephrocalcinosis in rainbow trouts and its prevention by various feeds. It was possible to depress nephrocalcinosis caused by a Cd content of the feed of 2 ppm by increasing the Ca share in the feed by 30 % and by adding 30,000 I.U. of vitamin D3. Also the fish health studies in the river Weser were continued. An experimental study on the importance of soluble gases for fish husbandry was carried out.
Bacterial diseases of fish were studied at the Landesanstalt für Fischerei Nordrhein-Westfalen. The Institut für Seenforschung und Fischereiwesen of the Landesanstalt für Umweltschutz Baden-Württemberg in Langenargen studied the suitability of the cells of the periphere blood as auxilary mean in the diagnosis of various trout diseases. Distinct influences on the composition of the periphere blood were observed in relation to water temperature and -quality, the age of the fish and to its physiological condition. The working group on fish pathology of the Institut für Hydrobiologie und Fischereiwissenschaft of the University of Hamburg studied the reaction of fish with regard to various environmental conditions. These studies revealed that especially the gill epithel and the blood producing organs are sensitive indicators for pollution loads. The experimental station Wielenbach of the Bayerische Landesanstalt für Wasserforschung continued its ecoparasitological studies with special reference to Triaenophorosis. The storage time of medicated feeds in fish was studied at the Bayerische Landesanstalt für Fischerei. The Institut für Meereskunde of the University of Kiel continued its program on the distribution of fish stocks and fish diseases in the lower Elbe. The Tiergesundheitsdienst Bayern e.V. studied the problem of high pH values in carp ponds responsible for gill necrosis. Parasitical infections of fish were studied at the Staatliche Tierärztliche Untersuchungsamt Heidelberg and the Genetische Institut of the Justusvon-Liebig-University in Giessen studied the effect of aflatoxins on the formation of tumours in fish.
III FISH AND POLLUTED WATER
The Institut für Küsten- und Binnenfischerei of the Bundesforschungsanstalt für Fischerei assessed the distribution of chlorinated hydrocarbons in filets of artificially fed European catfish. The chemical was distributed in the filet according to the distribution of the fat content. It was highest in the tail region. The distribution pattern has to be taken into account when taking samples from individual fish for chemical analysis. The Landesanstalt für Fischerei Nordrhein-Westfalen studied in several inland waters the influence of acid rain on the embryonal and fry development of the rainbow trout and the brook trout.
The use of fish cell cultures for toxicity testing was studied at the Institut für Zoologie und Hydrobiologie of the Veterinarian Faculty of the University of München, in order to reduce respectively substitute fish tests with this method. Criteria were the study of the cell morphology, the reproduceability and the lifespan of the cells. In comparison with the animal test it could be demonstrated that the cytotoxicity test was more sensitive and has the additional advantage of savings in material, time and money.
The effects of various immissions on the surface waters in the city of Hamburg were studied at the Institut für Hydrobiologie und Fischereiwissenschaft of the University of Hamburg. The results of the studies resulted in proposals for the reduction of immissions based on toxicity studies using the Daphnia and Hydroid test in harbour waters.
IV PRODUCTION STATISTICS
Inland fishery statistics are officially collected only every 10 years. The last survey was completed in 1981. Production figures for the years in between are rough estimates by the German Fisheries Association. According to these the following fish production was made in 1985:
| Consumption rainbow trouts | 14,000 tons | = | 91 million DM |
| Consumption carps | 6,200 tons | = | 20 million DM |
| Consumption fish from river and lake fisheries | 4,000 tons | = | 16 million DM |
| Total | 24,200 tons | = | 127 million DM |
V BIBLIOGRAPHIC REFERENCES
BAUER, J.: Limnologische Untersuchungen über die Bedeutung von Makrophyten für die Selbstreinigung und den Stoffhaushalt in stehenden Gewässern. Münchn. Beitr.Abwass.-, Fisch.-Fluβbiol. 39: 431–464, 1985.
BAUER, J.; LEHMANN, R.,; SCHMITT, P.: Gewässerversauerung und ihre biologischen Auswirkungen im Landkreis Cham. Umweltbericht 1985. Landkreis Cham 1985. S. 34–38.
BAYERISCHE LANDESANSTALT FÜR WASSERFORSCHUNG - Aufgaben, Ziele, Ergebnisse. München: Bayer. Staatsministerium f. Landesentwicklung u. Umweltfragen 1985. 80 S.
BAYERISCHE LANDESANSTALT FÜR WASSERFORSCHUNG; INSTITUT FÜR BOTANIK U. MIKROBIOLOGIE DER TU MÜNCHEN: Die Bedeutung von Makrophyten für die Gewässerökologie - Vegetationsentwicklung, Einflüsse auf den Stoffhaushalt in Gewässern. München: Bayer. Landesanstalt f. Wasserforschung 1985. 345 S.
BAYER. LANDESANSTALT FÜR WASSERFORSCHUNG; INSTITUT FÜR HYDRAULIK U. GEWÄSSERKUNDE: Erfassung der Strömungsverhältnisse und des Stoffhaushaltes eines stark durchströmten voralpinen Sees; Schluβbericht. Sonderforsch.bereich 81, TU München, Teilprojekt A5, 1985.
BAYRLE, H.: Fischereiliche Bedeutung und Nutzung von kleinen Gewässern. Bayer. Fischereigespräche (5): 168–186, 1985.
BAYRLE, H.: Der Hecht. Begleitkarte zum gleichnamigen Film. Grünwald: Institut für Film und Bild 1985.
BAYRLE, H.: Karpfen, wie man ihn vorbereitet, zubereitet, iβt. 2. Aufl. Starnberg: Bayerische Landesanstalt für Fischerei 1985.
BAYRLE, H.: Sicher durch die Fischerprüfung. Rechtskunde Bayern, Gesetzesauszug. Marktredwitz: Institut für moderne Lehr- u. Lernmethodik 1985.
BAYRLE, H.; HEINTGES, F.: Natur- und Tierschutz in der Angelfischerei, Teil 1. Marktredwitz: Institut für moderne Lehr- u. Lernmethodik 1985.
BAYRLE, H.; HEINTGES, F.: Versorgen und Verwerten von Fisch. 3. u. 4. Auflage. Marktredwitz: Institut für moderne Lehr- u. Lernmethodik 1985.
BAYRLE, H.: Fischerei und fischartenschutz. Wiedereinbürgerung und Neuansiedlung. SchrReihe Arbeitsgem. dt. Fischereiverwaltungsbeamten und Fischereiwiss. 1: 57–61, 1986.
BAYRLE, H.; HEINTGES, F.: Räuchern von Angelfischen. Marktredwitz: Institut f. moderne Lehr- und Lernmethodik 1986.
BOCK, R.: Beobachtungen über das Notatmungsverhalten des neotropischen Knochenzünglers Osteoglossum bicirrhosum. Dipl.-Arb., Fachber. Biol., Univ. Hamburg 1985.
BOHL, M.: Fischproduktion und Umwelt. Aqua-Fisch, Internat. Fachausstellung Friedrichshafen, Themenblock Berufsfischerei, 1985. 16 S.
BOHL, M.: Zur Notwendigkeit von Uferstreifen. Natur Landsch. 61 (4): 134–136, 1986.
CLEMMESEN, C.: Das Verhältnis von Ribonukleinsäure (RNA) zur Desoxyribonukleinsäure (DNA) bei hungernden und gefütterten Fischlarven. Dipl.-Arb., Univ. Kiel 1985.
DITTRICH, B.: Beiträge zur Biologie und Ökologie von Hyperia galba (Montagu, 1813). Diss., Univ. Bochum 1986, 202 pp.
FISCHER, L.: Binnenfischerei. Jber.dt.Fischw. 1984/85: 31–35, 1985.
FISCHER, L.: Binnenfischerei. Jber.dt.Fischw. 1985/86: 37–41, 1986.
FRANK, F.: Seriologische Untersuchungen über die Verbreitung der bakteriellen Nierenerkrankung (BKD) im Süden Baden-Württembergs. Diss., Univ. München 1986.
HALSBAND, E.: Elektrofischen ohne Folgen? Fliegen Fischen 2: 60–67, 1985.
HEIL, M.: Untersuchungen am Chromatin von tumorfreien, tumortragenden sowie mit Aflatoxin B1 behandelten Fischen der Gattung Xiphophorus. Diss., Univ. Giessen 1985.
JENS, G.: Versauern der Fischgewässer? Allg.Forstz. (25/26): 648–650, 1985.
KUHN, G.; HOFFMANN, R.: Untersuchungen zum Aufbau des Verdauungskanals der Goldorfe (Leuciscus idus L.). Zentbl.Vet.Med., C.Anat.Histol.Embryol. 14: 365–380, 1985.
LEHMANN, J.; MONTRONE, G.; STÜRENBERG, F.-J.: Die Auswirkung von medikamentösen Behandlungen auf den Fischorganismus, insbesondere auf das haematopoetische System. Teil A: Untersuchungen des Blutes und des Serums. Bonn: Bundesmin.Forsch.Technol., Juni 1985. BMFT-FB-M 85-001: 111 S., 1985.
LEHMANN, J.; SIEGERT, K.: Die Auswirkung von medikamentösen Behandlungen auf den Fischorganismus. Teil B: Rückstandsanalysen von Antibiotika auf Proben von Muskulatur (“Filet”), Leber, Milz und Niere. Bonn: Bundesmin.Forsch.Technol., Juni 1985. BMFT-FB-M 85-002: 32 S., 1985.
LELEK, A.: Kritische Stellungnahme zur Fischfauna der hessischen Gewässer. -Natur in Hessen, Bericht zur Lage der Natur. Wiesbaden 1985. S. 144–148.
LELEK, A.; PELZ, G. R.; BERNERTH, H.; TOBIAS, W.: Neue Wege zur Erhaltung von Feuchtbiotopen: Die Sprengung als ökotechnische Maβnahme in Naturschutzgebieten. Natur Mus. 115(12): 369–396, 1985.
LELEK, A.; BARLAS, M.; MEINEL, W.; PELZ, G. R.: Das Vorkommen der Fische in Flieβgewässern des Landes Hessen. In: Natur in Hessen. Wiesbaden: Fischkataster des Hess.Min.Landwirtschaft Forsten 1986. 72 S.
LELEK, A.; PELZ, G. R.: Der untere Main und seine Fische. Schützt die Gewässer 2: 8–12, 1986.
LELEK, A.; TOBIAS, W.: Results of the Mission to the Randenigala Man-made Lake, Sri Lanka. Rep. Joint Venture Randigale, August-September 1986. p. 1–38.
LUKOWICZ, M. v.: Bayerische Landesanstalt für Fischerei. Jahresbericht 1984. Starnberg, Juli 1985, 87 S.
NELLEN, W.; DEHUS, P.: Jüngere Ergebnisse zur Situation der Süβwassrefische in Schleswig-Holstein. Schr.Naturw.Ver.Schlesw.-Holst. 55: 63–80, 1985.
NELLEN, W.; DEHUS, P.: Jüngere Ergebnisse zur Situation der Süβwassrefische in Schleswig-Holstein. SchrReihe ArbGem. dt. FischVerwaltBeamten FischWiss. 3: 81–83, 1986.
PELZ, G. R.: Fischbewegungen über verschiedenartige Fischpässe am Beispiel der Mosel. Cour. Forsch.-Inst. Senckenb. 76: 190 S., 1985.
PETERS, G.; SCHWARZER, R.: Changes in hemopoetic tissue of rainbow trout under influence of stress. Dis.Aquat.Organism 1 (1): 1–10, 1985.
REINSCH, H. H.: Zur Vorkommen der Europäischen Sumpfschildkröte (Emys orbicularis) im Elbe-Weser-Dreieck. Beitr. Naturk. Niedersachsens 37 (4): 245–247, 1984.
SCHAUNER, M.: Untersuchungen zum serologischen Nachweis der Bakteriellen Nierenerkrankung (BKD) der Salmoniden. Diss., Univ. München 1986.
SCHULZ, D.; HARTFIEL, W.: Maiskleber als Hauptproteinträger im Alleinfutter für Regenbogenforellen (Salmo gairdneri, R.). Kraftfutter 3: 102–106, 1986.
SEEL, R.: Reaktionen eines Drehtrommelreaktors auf fluktuierende Belastungen in einem Seewasser-Fischzuchtkreislauf. Dipl.-Arb., Fachhochschule Hamburg 1986. 86 S.
TOTZ, W.: Das Makrozoobenthos der Schlei - Produktion und Bedeutung als Fischnahrung. Diss., Univ. Kiel 1986.
