Die deutsche Fischerei auf den "ozeanischen" Rotbarsch (Sebastes mentella) von 1995 bis 1998

Recently, the German redfish fishery displayed a pronounced seasonal pattern in geographic effort distribution and depth. The second and third quarters were the main season when 80 % of the effort was exerted. During the second quarter, the fleet activities were concentrated in international waters close to the Icelandic Exclusive Economic Zone (EEZ), fishing at depths exceeding 600 m. In contrast, the catches in the third quarter were taken mainly inside the Greenland EEZ at depths around 300 m. From 1995 to 1998, the annual effort ranged from 14 000 to 18 000 trawling hours, without a trend. This effort yielded about 18 000 to 21 000 t (international catch > 100 000 t) annually. Since 1996, the catch rate (CPUE) decreased during the main season. The decrease in CPUE should be interpreted as the first reaction of the stock to increased exploitation. The fish size also varied seasonally and peaked during the second quarter at depths exceeding 600 m. Here, males were bigger than females and both sexes were equally frequent. The increase of fish size with increasing depth did not contribute to the hypothesis of two separate pelagic redfish stocks above and below 500 m. In contrast, the close relation between fish size and depth point to the so-called “deeper-bigger phenomenon” which was found in numerous fish stocks. Very few redfish in the catches were immature.

Metals and pesticide levels found in fish taken from Vancouver Lake: memorandum to Steve O'Brien, dated May 19, 1977

The Vancouver Lake Pilot Dredge Study revealed concentrations of certain chemicals which could be of concern: the metals copper, zinc and mercury and the pesticides lindane and aldrin were found in significant amounts. (PDF contains 1 page)

Oceanographic, meteorological, satellite and aircraft observations for project Little Window 2: May 1971

ENGLISH: In May 1971, a joint united states - Mexican experiment, Project Little Window 2, (LW-2) involving data collected by satellite, aircraft and ship sensors was made in the southern part of the Gulf of California. LW-2 was planned as an improved and enlarged version of LW-l (conducted the previous year; Stevenson and Miller, 1971) with field work scheduled to be made within a 200 by 200 km square region in the Gulf of California. The purposes of the new field study were to determine through coordinated measurements from ships, aircraft and satellites, the utility of weather satellites to measure surface temperature features of the ocean from space and specifically to evaluate the high resolution infrared sensors aboard N~ 1, ITOS 1 and NIMBUS 4 and to estimate the magnitude of the atmospheric correction factors needed to bring the data from the spacecraft sensors into agreement with surface measurements. Due to technical problems during LW-2, however, useful data could not be obtained from ITOS 1 and NIMBUS 4 so satellite information from only NOAA-1 was available for comparison. In addition, a new purpose was added, i.e., to determine the feasibility of using an Automatic picture Transmission (APT) receiver on shore and at sea to obtain good quality infrared data for the local region. SPANISH: En mayo 1971, los Estados Unidos y México realizaron un experimento en conjunto, Proyecto Little Window 2 (LW-2), en el que se incluyen datos obtenidos mediante captadores de satélites, aviones y barcos en la parte meridional del Golfo de California. Se planeó LW-2 para mejorar y ampliar el proyecto de LW-l (conducido el año anterior; Stevenson y Miller, 1971), realizándose el trabajo experimental en una región de 200 por 200 km cuadrados, en el Golfo de California. El objeto de este nuevo estudio experimental fue determinar mediante reconocimientos coordinados de barcos, aviones y satélites la conveniencia de los satélites meteorológicos para averiguar las características de la temperatura superficial del océano desde el espacio, y especialmente, evaluar los captadores infrarrojos de alta resolución a bordo de NOAA 1, ITOS 1 Y NIMBUS 4, y estimar la magnitud de los factores de corrección atmosféricos necesarios para corregir los datos de los captadores espaciales para que concuerden con los registros de la superficie. Sin embargo, debido a problemas técnicos durante LW-2, no fue posible obtener datos adecuados de ITOS 1 y NIMBUS 4, as1 que solo se pudo disponer de la información de NOAA 1 para hacer las comparaciones. Además se quiso determinar la posibilidad de usar un receptor de Trasmisión Automático de Fotografias (APT) en el mar para obtener datos infarojos de buena calidad en la región local. (PDF contains 525 pages.)

Entgiftungsstoffwechsel der Nordsee-Kliesche (Limanda limanda)

In the framework of monitoring programmes organized under several sea protection conventions (HELSINKI Conv., OSPAR Conv.) the contracting parties are requested to develop appropriate techniques for Biological-Effect- Monitoring. In following these recommendations the Institut for Fisheries Ecology studies the 7-ethoxyresorufin- O-deethylase (EROD) activity in the liver of dab. EROD represents one enzyme of the cytochrome P-450 species, also called mixed function oxygenases (MFO), which is induced by certain organic contaminants, e.g. PCBs. On the other hand, an influence of natural factors like season, temperature or spawning on the EROD activity may be possible. The present study represents an insight into the status of the EROD activity in North Sea dab. Ultimately, we intend to decide if EROD activity is an appropriate tool to detect effects of contaminants. The EROD activity in the liver of 687 dabs, caught in the North Sea at different seasons in 1995 and 1996 with the fishery research vessel “Walther Herwig III”, has been determined and the data obtained have been statistically evaluated. The logarithmically transformed values of the EROD activity are following approximately a normal distribution. Due to the wide variation of the enzyme activities and due to the small number of samples minor differences between samples are not detectable. Nevertheless, comparing the enzyme activities at different sites of the North Sea, some significant differences have been identified. A model for the discription of seasonal variations of EROD activity, developed at the Biologische Anstalt Helgoland, could be helpful for interpretation.

Welt-Fischereierträge 1995: 112,9 Mio. Tonnen

Total world fishery production 1995, including aquaculture, of fish, shellfish, frogs and turtles – reached a new record of 112.9 million tones live weight. Marine fishery had a share of 91,9 million tonnes (+ 0.4) and freshwater fishery 21.0 million tonnes (+ 2.0). Not included in these figures are seals, whales, crocodiles and algae. Marine mammals and crocodiles are listed by number of killed individuals, and not given by weight. Algae alone represent a biomass of 7.1 million tonnes, but are not included by the FAO in the nominal „total production of the world“ either. About two thirds of the marine fishery harvest was used for human consumption, one third for industrial purposes – mainly production of fish meal and fish oil.

Frame survey of Kainji Lake, northern Nigeria, 1996

Since 1993, annual frame surveys have been conducted by the Nigerian-German Kainji Lake Fisheries Promotion Project to determine the distribution and number of fishing localities, fishing canoes and fishing gears around Kainji Lake, Nigeria. The total number of fishing localities has increased from 221 in 1993 to 286 in 1996. The fishing localities included 245 permanent fishing villages, 29 permanent fishing camps, 8 temporary fishing camps (with fishermen from Kainji Lake) and 4 temporary fishing camps (with fishermen from outside Kainji Lake area). There was an increase in the total number of fishing entrepreneurs, fishing assistants and fishing canoes over the years. A total number of 5,499 fishing entrepreneurs, 12,449 fishing assistants and 9,278 fishing canoes were recorded during the 1996 frame survey. From 1995 there was a decrease in the number of shoreline fisherfolk and a decrease in the number of transport canoes, the number of engines remained the same. During the 1996 survey, a total number of 18,655 gill nets, 1,560 drift nets, 753 beach seines, 5,548 cast nets, 7,400 longlines and 36,979 traps were recorded. The concentration of the gears (number per km shoreline) was highest in substrata 06 and 08. The total number of gill nets increased from 17,680 in 1995 to 18,655 in 1996. For the remaining 5 gear types a decrease in number was observed. Despite increasing numbers of gears on the lake, of concern is the decline recorded in all the fishing methods of the number of gears owned by individual entrepreneurs. This was most notable in the gill net and longline fisheries. These two fisheries have the lowest daily catch values and coupled with the problem of gear theft on the lake, ownership in future, may be expected to fall further. The number of larger fishing units also declined as did the number of gears new entrants enter the fishery with. The decline is particularly worrying for the beach seine fishery where diversification into other fishing methods would be beneficial in light of the present ban on seines. The group of not active fishing entrepreneurs (those who do not themselves participate in fishing activities) had the highest ownership of gears whilst the new entrants into the fishery had the lowest. There was evidence that these new entrants into the fishery were using cast nets which is worrying given the trend of using smaller mesh size of this gearSince 1993, annual frame surveys have been conducted by the Nigerian-German Kainji Lake Fisheries Promotion Project to determine the distribution and number of fishing localities, fishing canoes and fishing gears around Kainji Lake, Nigeria. The total number of fishing localities has increased from 221 in 1993 to 286 in 1996. The fishing localities included 245 permanent fishing villages, 29 permanent fishing camps, 8 temporary fishing camps (with fishermen from Kainji Lake) and 4 temporary fishing camps (with fishermen from outside Kainji Lake area). There was an increase in the total number of fishing entrepreneurs, fishing assistants and fishing canoes over the years. A total number of 5,499 fishing entrepreneurs, 12,449 fishing assistants and 9,278 fishing canoes were recorded during the 1996 frame survey. From 1995 there was a decrease in the number of shoreline fisherfolk and a decrease in the number of transport canoes, the number of engines remained the same. During the 1996 survey, a total number of 18,655 gill nets, 1,560 drift nets, 753 beach seines, 5,548 cast nets, 7,400 longlines and 36,979 traps were recorded. The concentration of the gears (number per km shoreline) was highest in substrata 06 and 08. The total number of gill nets increased from 17,680 in 1995 to 18,655 in 1996. For the remaining 5 gear types a decrease in number was observed. Despite increasing numbers of gears on the lake, of concern is the decline recorded in all the fishing methods of the number of gears owned by individual entrepreneurs. This was most notable in the gill net and longline fisheries. These two fisheries have the lowest daily catch values and coupled with the problem of gear theft on the lake, ownership in future, may be expected to fall further. The number of larger fishing units also declined as did the number of gears new entrants enter the fishery with. The decline is particularly worrying for the beach seine fishery where diversification into other fishing methods would be beneficial in light of the present ban on seines. The group of not active fishing entrepreneurs (those who do not themselves participate in fishing activities) had the highest ownership of gears whilst the new entrants into the fishery had the lowest. There was evidence that these new entrants into the fishery were using cast nets which is worrying given the trend of using smaller mesh size of this gear. (PDF contains 44 pages)

An evaluation of the pelagic primary productivity and potential fish yield of Kainji Lake, Nigeria

The environmental conditions of Kainji Lake from 1971/72 to date appear to have stabilized to a large extent, judging from the similarity of physico-chemical parameters investigated in this study over the period. Solar radiation (as reflected in variation in temperature) and pH have remained largely constant over the years, while conductivity (index of nutrient enrichment), though significantly higher in 1995/96, could be described as sporadic and needs further monitoring to ascertain its trend in the lake. While water transparency and dissolved oxygen were higher in 1971/72 compared to the other years, these increases cannot be said to be overwhelming. The lower transparency in 1995/96 was due to the exceptional flood of that year and may have also accounted for the poorer dissolved oxygen concentration compared to the other years due to its impact on photosynthesis. There is no evidence from this study to indicate that primary productivity has increased over the years. Consequently, the observed increase in fish yield by the KLFPP from CAS, which is corroborated by estimates from the MEI, cannot be supported on the basis of improved photosynthetic production. The phenomenal high levels of conductivity recorded during certain periods in 1995 (600 mu mhos cm super(-1)) are hitherto unknown in the lake and may indicate a trend towards nutrient enrichment. However, it is premature at this stage to conclude on its long-term impact on primary production and consequently, on fish yield. Secondly, the notion of overfishing in the 80s (Ita, 1993), may need to be further examined as low or dwindling catches could be due to a number of factors among which are the level of fishing effort, the type and efficiency of gears and the intensity of sampling. It would appear that with the intervention of KLFPP, the better management of the lake's fisheries would increase the current level of catch. It also needs to be examined how much of the clupeid fisheries, which is now known to account for a substantial proportion of the total fish yield in Kainji Lake, was included in the sampling of the 80s. (PDF contains 43 pages)

Sensorische Bewertung, Mikrobiologie und chemische Kenngrößen von eisgelagertem Wittling (Merlangius merlangus)

During the 160th research cruise of the FRV "Walther Herwig III" in the North Sea in May 1995 an ice-storage experiment with whiting was performed. Gutted whiting with and without spleen was stored in melting water-ice. Freshness and/or spoilage were monitored by measuring sensory, chemical, physical and microbiological indicators. It was found that besides the classical sensory assessment on the cooked sample and the EU-quality grading scheme, the microbiological counts were of major importance for the determination of the degree of freshness or spoilage. The cfu (colony forming units) of spoilage bacteria on the skin correlated significantly with time in ice. A very good correlation was also found for the cfu of spoilage bacteria with the sensory assessed odour of the cooked fillet sample. The measurement of the fish tissue with the Intellectron Fischtester VI and the determination of the creatine content in fillet are both suitable freshness and spoilage indicators. The pH-value measured in different body compartments and in musele homogenate and the ammonia content are only of limited value for freshness determination. Removal of kidney did not influence the shelf life.

Untersuchungen der Industriefischerei 1995/96

Information on the impact of industrial fishery on sandeel and sprat is given. First results of experimental fishing on board RV "Walther Herwig III" and results of studies aboard commercial vessels within the German Economic Zone are presented.

"Global Change" und das Meer als Nahrungsquelle

The potential importance of marine produetion as a protein ressource for a growing human population can hardly be overestimated. Climatic changes in the marine environment may affect marine production in a significant way. Increasing levels of UV-B may decrease primary production and thus diminish the food base for harvestable marine ressources. Direct effects on early stages of fishes may occur. Temperature changes can lead to additional mortality in the early phase of life histories of fishes. In spite of the potentially negative scenario, actual effects of global change on the ressources have not been detected so far. The marine organisms dispose of a significant level of pre-adaptation to changes of environmental factors both on a seasonal and an interannual scale. Effects on marine life may therefore be less dramatic than those on terrestrial systems, which are more directly linked with the exponentially growing human population.

Zeitweilige Schillzunahme als Voraussetzung starker Miesmuscheljahrgänge

The sandy and muddy bottom of tbe German Waddensea offers a great diversity of secondary substrates to mussel larvae ready to settle. But every substrate with the exception of dead shell material may result in very small mussel colonies only. Large mussel beds of a size up to many hectares depend on aggregations of molluscan shells covering comparably areas of ground. Such shell aggregations are created by extremely cold winters and during years with extended stormy periods.

The macroinvertebrate fauna of pools in the floodplain (fadama) of the Anambra River, Nigeria

The Anambra River is the largest tributary of the lower Niger River below Lukoja. Between the months of May and November the river is subject to seasonal flooding from heavy precipitation and land runoff into the drainage system. During the flood phase, pools form on the floodplains (known as the fadama) and these pools receive materials and biota from the main river channel. The biota often includes representatives of freshwater vertebrates (including fishes) and invertebrates. On this brief note, the authors report on the macroinvertebrates found during preliminary studies on four fadama pools during the non-flood season between December 1994 and April 1995. 523 specimens were collected, of which 86% were arthropods, 9% were annelids (mostly Tubifex and Nais) and a few leeches (Hirudo), and 5% were gastropod molluscs of the arthropods, 75% were insects particularly Hemiptera and Diptera.

Rapid changes in the vegetation of a shallow pond in Epping Forest, related to recent droughts

Over much of Britain, 1995 and 1996 have been perceived as drought years. To evaluate the impact that local climatic conditions are having upon successional changes in higher vegetation (macrophytes), Speakmans Pond in Epping Forest was surveyed and mapped in 1996. The results are related to previous vegetation surveys carried out in 1989 and 1991. In 1989 the dominant marginal vegetation was floating sweet-grass Glyceria fluitans, which also covered a major part of the main body of the pond. Other abundant species included soft rush Juncus effusus, reed mace Typha latifolia and yellow flag Iris pseudocorus. A small (central) area of open water contained bladderwort Utricularia vulgaris and white water-lily Nymphaea alba. A similar plant coverage was found in 1991, with a dominance of floating sweet-grass along the shallow eastern edge. A marked change in the pond was found during the 1996 survey of vegetation in July, when the pool was dry. The major plant cover now consisted of creeping bent Agrostis stolonifera, with isolated clumps of Yorkshire fog Holcus lanatus around the edges; both are terrestrial grasses found on land surrounding the pond. Rushes (Juncus) had increased their distribution round the margins of the pond, and the patch of yellow flag noted in 1989 and 1991 was not found in 1996. The deeper trenches were also dry, but a small patch of white water-lily remained adjacent to one of the trenches.

Use of macroinvertebrate communities to detect environmental stress in running waters

This paper presents an account of some current uses of RIVPACS (River Invertebrate Prediction and Classification System), a software package developed by the Institute of Freshwater Ecology (UK). Background information is also given on the unique data-set on which the system is based. Before discussing RIVPACS, we consider the range of environmental stresses encountered in flowing-water systems and some of the ways in which stresses may affect macroinvertebrate communities. The wide application and relevance of the RIVPACS approach was recognised when it was chosen as the biological method for use throughout the UK in the 1990 River Quality Survey (RQS). In the concluding section we list some lessons learnt both from the 1990 survey and from our own testing exercise, and we outline current developments which will lead to a new version of RIVPACS for use in the 1995 RQS.