Ausbau der Unterwasser-Beobachtungstechnik im Institut für Fischereitechnik der Bundesforschungsanstalt für Fischerei, Hamburg

Die Unterwasser-Beobachtungstechnik mit Hilfe von Videokameras wurde nach 1945 entwickelt und erzielte in den 50er Jahren ihre ersten aufsehenerregenden Erfolge auf dem Gebiet der Wracksuche. Versuche mit der neuen Technik in der Fischereiforschung ließen gleichzeitig die Grenzen bei der Beobachtung von fischereilichen Fanggeräten und -objekten erkennen: die geringe Lichtstärke der verfügbaren Kameras erforderte den Einsatz von Kunstlicht, d.h. eine Beobachtung des Fangprozesses unter "natürlichen" Bedingungen ohne Zusatzbeleuchtung war nicht möglich. Diese Einschränkung sowie die am Beginn jeder technischen Entwicklung unvermeidlichen Kinderkrankheiten verhinderten zu dieser Zeit die allgemeine Einführung der Unterwasser-Beobachtungstechnik mit Video-Kameras in der Fischereiforschung.

Length-weight relationships of demersal fishes from the Gulf of Salamanca, Colombia: [part 2]

The parameters a and b of the length-weight relationship of the form W=aL super(b) are presented for 37 fish species, belonging to 17 families, caught during a demersal trawl survey over the period December 1995 to March 1998 in the Gulf of Salamanca, Colombia

Length-weight relationships of demersal fishes from the Gulf of Salamanca, Colombia

The parameters a and b of the length-weight relationship of the form W=a L super(b) were computed for 46 species caught in a series of demersal trawl hauls over the period 1995-1997 in the Gulf of Salamanca, Colombia.

Ökonomische Betrachtungen zu kurz- und langfristigen Maßnahmen in der Fischerei. Vorstellung von drei Forschungsprojekten

At present, there is practically no research on fisheries economics in Germany. Due to special interest of a research assistant in the field of land economics at the Institute of Botany of the University of Greifswald two projects on fisheries economics are being carried out, and a Ph. D. thesis on this topic has been finished. Basically two levels must be distinguished: business level and economics. Business economics relate mainly to operational and market analysis, but also to consequences of political measures for a single company. Economical considerations relate to long-term measures. It is important to find a compromise between short-term economical success and stable long-term conditions for the fishery.

Biologie de Penaeus duorarum (Burkenroad) en Côte d'Ivoire: croissance

The Petersen method was used to make growth assessments from experimental data collected during 1966-67 and 1969-70. The parameters K and L ∞ were calculated from the Von Bertalanffy growth curve. There was very little difference between the two years although growth in 1969 appeared slightly greater. A comparison of our results in Côte d'Ivoire with those from Senegal and Gulf of Mexico showed that the greatest growth occured on the west African coast and especially off the Côte d'Ivoire.

Biologie de Penaeus duorarum notialis en Côte d'Ivoire. 5 - Nouvelle étude de la croissance

Von Bertalanffy's growth curve parameters K, L∞ and t'o have been estimated for female Penaeus duorarum by modal progression analysis, using the "successive maximums method" of Gheno and Le Guen (1968) for the polymodal size frequency curves analysis and the Tomlinson and Abrahamson's least squares method for parameters computations. For the male the authors used an original method to get an age/length key. The parameters were calculated by Gulland's graphical method (1969).

Simulation stochastique des structures démographiques. Application aux populations d'albacores, Thunnus albacares

A computer program has been written in order to generate a population of fishes following a Von Bertalanffy growth curve with a random Gaussian variability for birth dates and growth parameters K and L ∞. Standard deviations for these 3 parameters are chosen separately for each run. Fishing and natural mortalities are applied to this population. Using as an input parameters usually taken for yellowfin in the eastern Atlantic, the simulation suggests a standard deviation between 1 and 2 months for the birth dates in this population. It also indicates that increasing levels of fishing mortalities must produce a better agreement between age and length for the larger fish.

Biologie de la phase lagunaire de Penaeus duorarum en Côte d'Ivoire: biométrie et croissance.

Principal biometric relations have been calculated for juvenile pink shrimp Penaeus duorarum, of Côte d'Ivoire lagoons. Growth has been studied from weekly sampling using Petersen's method and Von Bertalanffy's equation. Results are very similar to those obtained by the authors working in the same environmental conditions, especially concerning temperature.

Food conversion efficiency and the von Bertalanffy growth function. Part II and conclusion: Extension of the new model to the generalized von Bertalanffy growth function

The simple model relating food conversion efficiency (K sub(1)) to body weight derived from the theoretical concepts behind von Bertalanffy's growth model, is extended here in the context of Pauly's generalization of that model. The exponent, which was fixed to 1/3 in the simple model, is in the extended model equivalent to 1-d, with d being the weight exponent of the anabolism term in Pauly's growth model. This makes the model applicable to fish for which the assumptions of the original (special) version of von Bertalanffy's growth model are violated.