Technische Maßnahmen zur Schonung des Ostseedorschs - Gegenwärtige Ergebnisse der Selektionsforschung

Die gegenwärtige Situation der westlichen und östlichen Dorschbestände in der Ostsee wird von den Experten des Internationalen Rates für Meeresforschung, verglichen mit den 80er Jahren, als ungünstig beurteilt. Noch 1994 wurde daher kein Anlaß gesehen, trotz massiver Proteste der Praxis, die Empfehlung für eine moderate Befischung aufzuheben (Anon. 1994).

Recherches sur l'embryologie des gastropodes

(PDF contains 167 pages and 22 plates)

Producción y gestión de la industria lítica de Atxoste (Álava): Una aproximación a las sociedades Epipaleolíticas y Mesolíticas del alto Ebro

1000 p. (Anexos: 929-965 p.; bibliografía 965-1000 p.). Capítulos de discusión y conclusiones en castellano y francés.

Analyse des Fluchtverhaltens von Fischen auf Schiffsgeräusche mit hydroakustischen Methoden

Investigations on the avoidance reactions of pelagic schooling fish (herring and sprat) released by an approaching fishery vessel were carried out during the 378th cruise of FRC "Solea" from 25 September to 3 October 1995 in the Arkona Sea, southern Baltic. An echosounder system EK 500/BI500 with a 38 kHz transducer mounted on a towed body as weIl as a 120 kHz hull mounted transducer were used. Fish densities were measured synchronously as well as under the ship as at a laterally distances from the ship by the transducer of the towed body. By these means the variation of fish densities up to a certain distance from the ship is possible. The advantage of using an echo integrating system for these measurements is, that it works also for not schooling fish and under conditions where schooling fish disperse (e.g. at night).

Ist die gegenwärtig verstärkte Einwanderung südlicher Fischarten in die Nordsee schon eine Folge des Treibhauseffektes

Due to the greenhouse effect,a long term warming of the atmosphere is expected. For most people the last relative mild winters and the previous two hot summers are clear signals for such a climatic change. Changes in species compositions and the sudden arrival of southern species in the North Sea are explained as consequences of the greenhouse effect. Comparing the situation in the last decades an attempt is made in this article to show the natural variability in the occurrence and to give an answer to the above question.