Semblanzas Ictiológicas: Marcelo Gabriel Schwerdt

A través de esta serie intentaremos conocer diferentes facetas personales de los integrantes de nuestra “comunidad”. El cuestionario, además de su principal objetivo, con sus respuestas quizás nos ayude a encontrar entre nosotros puntos en común que vayan más allá de nuestros temas de trabajo y sea un aporte a futuros estudios históricos. Esperamos que esta iniciativa pueda ser otro nexo entre los ictiólogos de la región, ya que consideramos que el resultado general trascendería nuestras fronteras.

Semblanzas Ictiológicas: Gabriel Luis Paccioretti

A través de esta serie intentaremos conocer diferentes facetas personales de los integrantes de nuestra “comunidad”. El cuestionario, además de su principal objetivo, con sus respuestas quizás nos ayude a encontrar entre nosotros puntos en común que vayan más allá de nuestros temas de trabajo y sea un aporte a futuros estudios históricos. Esperamos que esta iniciativa pueda ser otro nexo entre los ictiólogos de la región, ya que consideramos que el resultado general trascendería nuestras fronteras.

Bacterial and pathological study of caudal fin rot in brood stocks of Salmo trutta caspius from the propagation and breeding center of Shahid Bahonar of Kelardasht region

In order to study caudal fin rot with emphasis on Aeromonas hydrophila and Pseudomonas fluorescens in Salmo trutta caspius from the salmonids propagation and breeding center of Shahid Bahonar of kelardasht region, One hundred and eighty brood stocks having fin damage symptoms were chosen. Two bacterial samples from each fish were cultured on Aeromonas and Pseudomonas specific media. Biochemical tests, API2OE identification system and antibiogram test using six antibiotic disks were performed for diagnosing isolates bacteria and finding suitable antibiotic. Thirty samples from caudal fin of damaged fishes were fixed in 10% formalin and 51.tm microscopic sections were prepared using standard scatological methods and then stained by Haematoxylin-Eosin staining method to observe the pathological changes and also Maccallum-Goodpasture staining method to observe the bacterial colonies. In second stage of the study, bacterial samples were taken from thirty brood stocks using similar method at the first stage of sampling. For isolation and biochemical diagnosis of Aeromonas and Pseudormonas genus, the samples were analyzed by molecular research included PCR amplification (using 16S rDNA genes of the genus pseudomonas and 16S-23S rDNA intergenic spacer of the genus Aeromonas) and restriction analysis by four restriction enzymes for each genus. The results of biochemical tests showed that isolated bacteria were belonged to Aeromonas caviae and Aeromonas hydrophila (subspecies anaerogenes), Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas alcaligenes while the results of API2OE identification system showed that the isolated bacteria belonged to Aeromonas hydrophila, Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas aeruginosa. Restriction analysis of Aeromonas samples with Hin6l, Csp6I, Taql, and Tasl revealed three samples were different from others while restriction analysis of Pseudomonas samples with Alul, Hinfl, Rsal, and Trull showed at least five species or biovars. The results of antibiogram test showed all Aeromonas samples were sensitive to Trimethoprim, Chloramphenicol and Nitrofurazone, mostly to Nalidixic acid and Chloramphenicol, while most of samples were resistant to Erythromycin and Oxytetracycline. Pseudomonas samples were only sensitive to Nitrofurazone and mostly resistant to Oxytetracycline, Nalidixic acid, Erythromycin, Trimethoprim and Chloramphenicol. The results of light microscope study showed hyperplasia and spongiosis of the malpigian cells of epidermis, increasing of melanin pigments underlying epidermis; sever necrosis in both epidermis and dermis and also sloughing the epidermis in some cases. Occurrence of clefts through the epithelium, neovascularization, hyperemia and mild inflammatory response in dermis and separation of the fin rays also were observed. No bacterial colonies were found in the sections.

Designing marine fishery reserves using passive acoustic telemetry

Marine Fishery Reserves (MFRs) are being adopted, in part, as a strategy to replenish depleted fish stocks and serve as a source for recruits to adjacent fisheries. By necessity, their design must consider the biological parameters of the species under consideration to ensure that the spawning stock is conserved while simultaneously providing propagules for dispersal. We describe how acoustic telemetry can be employed to design effective MFRs by elucidating important life-history parameters of the species under consideration, including home range, and ecological preferences, including habitat utilization. We then designed a reserve based on these parameters using data from two acoustic telemetry studies that examined two closely-linked subpopulations of queen conch (Strombus gigas) at Conch Reef in the Florida Keys. The union of the home ranges of the individual conch (aggregation home range: AgHR) within each subpopulation was used to construct a shape delineating the area within which a conch would be located with a high probability. Together with habitat utilization information acquired during both the spawning and non-spawning seasons, as well as landscape features (i.e., corridors), we designed a 66.5 ha MFR to conserve the conch population. Consideration was also given for further expansion of the population into suitable habitats.

The Effects of Salinity, Temperature, and Food on the Growth and Reproductive Output of Polydora nuchalis Woodick, 1953

Polydora nuchalis Woodwick, 1953 (Polychaeta: Spionidae) is a protandric hermaphrodite commonly inhabiting intertidal mud flats in southern California. The species exhibits lecithotrophic larval development and adelphophagia. Reproduction of P. nuchalis was monitored for a year at four sites: Catalina Harbor, San Gabriel River, Huntington Harbour, and Malibu Lagoon. Females deposited from 11 to 31 egg capsules in their tubes, with up to 230 eggs per capsule. An average of 3% of the eggs developed into larvae: the remaining were nurse eggs serving as food for the developing larvae. Reproductive output was quantified by determining the number and size of larvae and nurse eggs for individual capsules. Significant differences among the four populations were found for all the quantified variables. In addition, two size classes of nurse eggs were found to exist in capsules from all of the sites. Egg capsules were found throughout the year at San Gabriel River, but none were found during the winter months at the remaining three sites. Size/frequency data for juveniles and adults of the Catalina Harbor population indicate an annual cycle of recruitment. The laboratory experiment consisted of a 3 x 3 x 2 £actor1al design with replication testing the effects of temperature, salinity, and food supply on growth and reproduction of P. nuchalis. Increasing temperature resulted in significantly increased survivorship, growth rates, and percentage reproduction. It also produced a significant decrease in the size of the nurse eggs and the volume of food per larva. The number of egg capsules was maximum at the intermediate temperature. Increasing the salinity resulted in significant increases in survivorship and Class I nurse egg size. Increaaing food availability produced a significant increase in the percentage of worms reproducing. The interactive effect of salinity and £ood level produced significant changes in the number of larvae per capsule and the number of nurse eggs per capsule. However, the number of nurse eggs per larva did not differ significantly among the experimental treatment groups. (PDF contains 129 pages)

Neues Institut für Fischereitechnik und Fischqualität. Zusammenlegung der Institute für Fischereitechnik und Biochemie und Technologie

Entsprechend dem Rahmenkonzept für die Bundesforschungsanstalten im Geschäftsbereich des damaligen Bundesministeriums für Ernährung, Landwirtschaft und Forsten vom 12. 6. 1996 ist an der Bundesforschungsanstalt für Fischerei in Hamburg die Anzahl der Institute von fünf auf vier zu reduzieren. Das ab 1. 1. 2001 neu gebildete Institut für Fischereitechnik und Fischqualität (IFF) nimmt die Forschungsaufgaben der beiden bisherigen Institute für Fischereitechnik (IFH) sowie Biochemie und Technologie (IBT) wahr. Damit bietet sich für das aus zweivergleichsweise kleinen Instituten hervorgegangene IFF die Möglichkeit, in einem integrierten Ansatz Fische, Krebse und Weichtiere auf verschiedenen Stufen der Produktions- und Verarbeitungskette zu untersuchen und zu bewerten. Fangprozess und Folgebehandlung der Fangobjekte werden dadurch ganzheitlich betrachtet, was sich nicht zuletzt in Maßnahmen zur Qualitätserhaltung und -verbesserung von Fischen und Fischereierzeugnissen niederschlagen soll.

Weitere Selektionsuntersuchungen an Schleppnetzsteerten für den Plattfischfang in der Ostsee

The presentation includes investigations and results regarding Baltic flatfish selectivity with different trawl codend constructions. These investigations were carried out 1999/ 2000 on board of FRV “Clupea” and a commercial 17 m cutter. As could be shown, both an enlarged mesh size and another mesh form than rhombic can improve the selectivity of these fish. As flatfish catches with trawls mostly also cover cod, this mixed fishery at the southern Baltic coast should in future be managed by differentiated technical regulations for an improved selectivity. The results, also based on UW observations, current measurements, and wind tunnel tests with models, demonstrate some possible technical solutions.

Gegenüberstellung von mathematisch-physikalischer Modellierung und Messungen an geschleppten fischereitechnischen Systemen

When drafting a new model of a towed technical system for fisheries (trawl, towed TV gear or similar), and also when measuring an existing and already tested system it is not easy to foresee of practical behaviour, which depends of various parameters. The measuring programme for recording all data needs a lot of time and money, and also has some limitations. Therefore we developed for such systems mathematical-physical models, which allow a complex calculation. Their real value, however, results only from practical verification. During the cruise no. 222 of “Walther Herwig III” in November 2000 comparative investigations for 2concrete systems were carried out. This was done in cooperation with the University in Rostock, where such models are being developed and computerized. One of the systems mesasured was a pelagic herring trawl and the other one the towed TV gear for underwater observations of the Institute for Fishery Technology and Fish Quality. The correspondence between model calculation and measurements was very high for both systems.

Ostseedorschselektion - bestehende und vorgesehene neue technische Maßnahmen

Since the beginning of the nineties the situation of the Baltic cod stock is deteriorating constantly. The fishery administration (International Baltic Sea Fisheries Commission) tries to counter this by issuing new technical measures. Existing measures (raise of mesh opening from 105 to 120 mm, “Danish” and “Swedish” escape windows) and newly introduced technical measures (BACOMA codend and raise of the mesh opening in conventional codends to 130 mm) show a number of deficiencies putting their efficiency in doubt. Available well tested alternatives to the newly introduced measures without their negative side effects (codends made of netting turned by 90°, and other designs) are presently left out of regard. Models of socioeconomic effects are likewise ignored.

Konzept für eine bestandsschonendere Nutzung der Dorschvorkommen in der westlichen Ostsee

The introduction of a long-term management plan for the cod socks by the International Baltic Sea Fishery Commission (IBSFC) to ensure stable and high yields and to conserve the fish stocks of the Baltic demands certain conservation measures. One is the use of the Total Allowable Catches (TACs) based on precautionary approches. In addition the exploitation pattern and the selectivy of trawls shall be improved to increase the spawning stock biomass and to reduce the presently high discard rates. The contributation demonstrates by means of model calculations for the cod stock of the ICES Sub-divisions 22 to 24 ( Western Baltic ) the short- and long-term effects of an improvement of the trawl selectivity on stock size, yields and profit.

Selektionsuntersuchungen an Schleppnetzsteerten für den Plattfischfang in der Ostsee

The intensified trawl fishery for flounder and otherflatfishes along the German Baltic coast during summer months resulted in the problem of increased undersized bycatches and their discarding. Thereforeselectivity trials with a standard codend, a codend withenlarged meshes and a so-called multipanel codendwith partly transverse netting were investigated. Results show that improvements in selectivity are possible, and tests including UW-TV observations shouldbe continued.

Neuartige flexible Selektionseinrichtungen für Schleppnetzsteerte

Die wissenschaftlich-technische Zusammenarbeit zwischen dem Institut für Fischereitechnik (IFH) und dem russischen Institut MariNPO in Kaliningrad war 1997/98 schwerpunktmäßig auf die Entwicklung flexibler Vorrichtungen zur Größenselektion von Fischen in Schleppnetzsteerten sowie deren gemeinsame Erprobung in der Ostsee-Dorschfischerei ausgerichtet. Die Vorteile solcher flexiblen Vorrichtungen aus textilem Material verglichen mit starren, meist aus Metall gefertigten bestehen darin, daß sie bei der Handhabung keine dauerhaften Verformungen bekommen, keine Erschwernisse oder Gefährdungen der Decksbesatzung, insbesondere bei schwerem Wetter, verursachen und problemlos mit dem Netz aufgetrommelt werden können. Außerdem sind sie wesentlich billiger in den Anschaffungskosten als Metallgitter aus nichtrostendem Stahl. Ihre Installation vor dem Hievteil ermöglicht zudem ein ungestörteres Selektieren als bei Fluchtfenstern im Bereich des Steertendes, wo die Fische stark verdichtet sind und mehr oder weniger gewaltsam an bzw. durch die Maschen gepreßt werden. Der Umlauftank in Kaliningrad sowie das geschleppte, steuerbare UW-Videosystem des IFH bieten gute Voraussetzungen für eine umfassende experimentelle Untersuchung der entwickelten Vorrichtungen, über die im folgenden berichtet wird.

Fangtechnische Möglichkeiten zur Reduzierung des Beifangs von Meeresenten in der Dorschfischerei mit stationären Fanggeräten

The present contribution summarizes results of fishery investigations with gillnets and longlines in the winter cod fishery which had been carried out in the western Baltic region from 1996 to 1999 by the Bundesforschungsanstalt für Fischerei with financial aid of the country Schleswig-Holstein. The main goal of these investigations was to point out technological possibilities for a reduction of unwanted bycatches of sea ducks in gillnetting. As it is obviously impossible to reduce the local and temporal bycatch problem by means of different gillnet constructions or tactical measurements, only the temporary avoidance of fishing grounds with high abundance of ducks or the change to longlining as catch method with reduced duck bycatches may be an effective solution.

Fischereiforschungskutter "Clupea" 50 Jahre

Der seit 1. Januar 1992 vom damaligen Bundesamt für Ernährung und Forstwirtschaft, der heutigen Bundesanstalt für Landwirtschaft und Ernährung (BLE) bereederte und für Arbeiten der Bundesforschungsanstalt für Fischerei (BFAFi) verfügbare Fischereiforschungskutter (FFK) „Clupea“ wurde vor 50 Jahren am 7. November 1949 als Fischereikutter SAS 115 „Erfurt“ in Saßnitz in Dienst gestellt. Nach der Verlagerung einiger 17-m-Kutter an den Standort Karlshagen auf Usedom wurde daraus die „WOG 83“ (1955) und später die „KAR23“. Die „Erfurt“ wurde als Gespannpartner in der Heringsfischerei sowie autonom im Dorsch- und Plattfischfang mit Schleppnetzen eingesetzt.

Mechanisierte Aalfallenfischerei in Holland

Eel trapping seems to be one of the possibilities to replace the German eel trawl fishery on cutters in the Baltic with a high amount of unwanted and discarded bycatch by a more effective method. To prepare our own practical application the highly developed mechanized eel trap fishery on a commercial vessel in the Netherlands was studied. The results of this study are described in the this article.