Weitere Untersuchungen zur Selektion des Ostseedorsches mit neuartigen Steertkonstruktionen

Trotz der 1993 getroffenen Entscheidung der Internationalen Ostseefischereikommission, die Steertmaschenmindestöffnung von 105 auf 120 mm zu erhöhen, hat sich die allgemeine Situation der Dorschbestände in der zentralen Ostsee (Ernst 1998) bisher nicht verbessert. Man muß daher fragen, warum bisher keine wirksamen technischen Maßnahmen zum Schutz der Jungfische eingeführt und durchgesetzt worden sind. Die Entscheidung zur Einführung einer erhöhten Steertmaschenöffnung wurde 1993 bereits durch Einsprüche der Praxis relativiert. Es wurde von der Fischereipraxis verlangt, alternative Steertkonstruktionen zuzulassen, die es gestatten würden, die mit einem Steertwechsel verbundene Kosten zu minimieren. Dem war mit der Maßgabe zugestimmt worden, daß für solche alternativen Steerte der Nachweis geführt wird, daß mindestens 50 % der Dorsche von 38 cm Länge noch entkommen können. Zwei neuartige Steertformen, die sogenannte "schwedische" und die "dänische" (Dahm und Thiele 1996), wurden dann - allerdings ohne solchen gesicherten Nachweis - in das Regelwerk der Ostseefischereikommission aufgenommen und als zulässig erklärt.

Die Entwicklung des atlantischen Kabeljaubestandes vor Grönland in der zweiten Hälfte des 20. Jahrhunderts

Based on the results of an analytical assessment, the Atlantic cod stock off Greenland collapsed already in the late 60s and, since then, reached rarely the 10 % level of its size in 1955. Applying the concept of a self-sustaining stock, the drastic harvesting strategy of the past four decades must be considered inadequate. The stock collapse was therefore found consistent with annual exploitation rates being not adjusted to conservative management options and exceeding the productivity of the stock by far. The results of a multiplicative model explained the following recruitment failure based on significant effects of spawning stock size as well as temperature. Certainly, cold periods have negatively affected the recruitment process and consequently contributed to the stock collapse. However, such ecological effects should not be itemized causal but must be taken into account regarding appropriate stock management. Till today, the spawning stock remained severely depleted causing a low probability of a successful recruitment and a substantial stock recovery.

Die Neustrukturierung der Übereinkommen zum Schutz der Meeresumwelt des Nordostatlantiks und der Ostsee

Das am 16. November 1994 in Kraft getretene Seerechtsübereinkommen der Vereinten Nationen (United Nations Convention on the Law of the Sea) regelt völkerrechtlich alle Nutzungsarten der Meere. Die dort erlassenen Vorschriften beschränken sich auf allgemeine Rechtsgrundsätze, seerechtliche Kompetenzregelungen und Staatenverpflichtungen zum Erlaß internationaler und nationaler Regelungen. Das Vertragswerk bezieht den marinen Umweltschutz, einen Kernbereich globaler Umweltpolitik, ausdrücklich mit ein. Wesentlich konkreter in der Umsetzung umweltpolitischer Ziele sind die internationalen Übereinkommen zum Schutz der Meeresumwelt. Für den in Abbildung 1 gezeigten Teil des Nordostatlantiks einschließlich der Nordsee existieren derartige Übereinkommen bereits seit 1972 durch das OSLO und PARIS Übereinkommen und für die gesamte Ostsee seit 1974 durch das HELSINKI Übereinkommen. Im Lichte des heutigen Umweltverständnisses und unter Berücksichtigung des weiterentwickelten Seerechts wurden beide Übereinkommen 1992 neu gefaßt. Die politischen Veränderungen haben insbesondere im Ostseeraum auch zu geographischen Erweiterungen geführt. Die mit der Novellierung der jeweiligen Übereinkommen verbundene Neuorganisation ist weiterhin selbstverständlich von den Erfahrungen aus der zwanzigjährigen Überwachungstätigkeit und dem in dieser Zeit durch die Meeresforschung gewachsenen Wissen geprägt.

Die Entwicklung wichtiger Fischbestände in der Nordsee und im Nordatlantik. Ergebnisse der Herbstsitzung des Advisory Committees for Fishery Management des internationalen Rates für Meeresforschung

The October meeting of the ACFM of ICES gave advice for a number of North-Atlantic fish stocks. The results of the most important stocks are given here from the perspective of German fishery management. The are chiefly North Sea plaice and sole, for which a reduction of 25 % of the fishing mortality (F) is recommended for 1998, North Sea saithe (minus 20 % in F), while North Sea cod is in the process of recovery and North Sea haddock is inside safe biological limits. The mackerel stock of the North Sea has not yet recovered, while the western mackerel stock as an entity has stabilised at a level of about 2.3 million t.

Neue Erkenntnisse zur Verteilung des Nordseeherings auf die Gebiete der EU und Norwegens

A study by K.R. Patterson of the Marine Lab, Aberdeen, Scottland, presented to the EU comission in June 1997, investigated the distribution of Herring in the North Sea, i. e. the zonal attachment of the stock to EU and Norwegian waters, respectively. Evaluation of data from the ICES International Bottom Trawl Surveys and Herring Acoustic Surveys conducted in the last 10 years showed a wide variation in biomass and zonal attachment, depending on the type of survey used and the season sampled. However, a mean share of 16 % was estimated to be attached to the Norwegian waters . In contrast to earlier analyses based on commercial catches there is little support that this proportion increases with increasing stock size. It is expected that this study will give rise to some discussion on the forthcoming EU-Norwegian consultations on North Sea herring.

Über die Herkunft des starken Kabeljau-Jahrgangs 1996 in der Nordsee

Cod in the North Sea is expected to reach „Safe biological limit“ due to a strong 1996 year-class. The cod fry was seen first as 5 cm fingerlings in the catches during a hydroacoustic survey in the southeastern North Sea. Back-calculations of the water drift show with high probability that the respective spawning ground was situated in the southwestern North Sea.

Zur Bedeutung des Größenunterschieds weiblicher und männlicher Nordseegarnelen für die kommerzielle Garnelenfischerei

Aiming at a better knowledge on the distribution and fecundity of hibernating Crangon crangon (L.), the R.V. "Solea" in January is sampling shrimps in the German Bight since 1991. A total of 3.000 shrimps (1.608 females and 1.392 males) have been investigated with regard to total length, to the width of the carapace and to spawning activity.

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).

Non-governmental organizations and multi-sited marine conservation science: A case study

Non-governmental organizations (NGOs) are now major players in the realm of environmental conservation. While many environmental NGOs started as national organizations focused around single-species protection, governmental advocacy, and preservation of wilderness, the largest now produce applied conservation science and work with national and international stakeholders to develop conservation solutions that work in tandem with local aspirations. Marine managed areas (MMAs) are increasingly being used as a tool to manage anthropogenic stressors on marine resources and protect marine biodiversity. However, the science of MMA is far from complete. Conservation International (CI) is concluding a 5 year, $12.5 million dollar Marine Management Area Science (MMAS) initiative. There are 45 scientific projects recently completed, with four main “nodes” of research and conservation work: Panama, Fiji, Brazil, and Belize. Research projects have included MMA ecological monitoring, socioeconomic monitoring, cultural roles monitoring, economic valuation studies, and others. MMAS has the goals of conducting marine management area research, building local capacity, and using the results of the research to promote marine conservation policy outcomes at project sites. How science is translated into policy action is a major area of interest for science and technology scholars (Cash and Clark 2001; Haas 2004; Jasanoff et al. 2002). For science to move policy there must be work across “boundaries” (Jasanoff 1987). Boundaries are defined as the “socially constructed and negotiated borders between science and policy, between disciplines, across nations, and across multiple levels” (Cash et al. 2001). Working across the science-policy boundary requires boundary organizations (Guston 1999) with accountability to both sides of the boundary, among other attributes. (Guston 1999; Clark et al. 2002). This paper provides a unique case study illustrating how there are clear advantages to collaborative science. Through the MMAS initiative, CI built accountability into both sides of the science-policy boundary primarily through having scientific projects fed through strong in-country partners and being folded into the work of ongoing conservation processes. This collaborative, boundary-spanning approach led to many advantages, including cost sharing, increased local responsiveness and input, better local capacity building, and laying a foundation for future conservation outcomes. As such, MMAS can provide strong lessons for other organizations planning to get involved in multi-site conservation science. (PDF contains 3 pages)

Recherches sur l'embryologie des gastropodes

(PDF contains 167 pages and 22 plates)

Impact of radio broadcast on fish production and conservation in Kainji Lake basin

The decline in fishermen catches of Lake kainji, which went down from 28,639.6t in 1970 to 6.048t in 1974 (Ita 1982) prompted the promulgation of fisheries edict banning beach seines and other obnoxious fishing gear by Kebbi and Niger State governments in 1997 as a measure to prevent depletion of fisheries resources in the lake. Radio as a medium of communication was adopted as the method to disseminate information in the fisheries edict to the fisherfolks in order to bring about positive changes. Radio Niger, Koro station, was involved in the broadcast. Fisherfolk listened to the broadcast 32 times a week. Frame survey data and radio impact assessment studies were used to assess the effect of the broadcast on the number of beach seines and other obnoxious fishing gears on the lake which were banned in the fisheries edicts. It was revealed that the number of beach decreased drastically from 582 in 1997 to 122 in 1999 and to only 17 in 2001

Conservation and sustainable utilization of Nigerian ornamental fishes

The paper assessed qualitatively the threat status of nigerian freshwater fishes that are presently being exported and those that have potential in aquarium trade using such criteria as rarity, size at maturity, mode of reproduction, human population density, habitat degradation, pollution and range of each species among others. For their conservation captive breeding of these fishes were proffered with information that can assist collectors, exporter and aquaculturists that wants to breed polypterids, Butterfly fish, Knife fish, Elephantfish, Pollymyrus isidori, Arnordichthys spilopterus, Nannaethiops unitaeniatus, Killifishes, Polycentropsis abbreviatta, Cichlids, Ctenpomas, Mastacembelids and Tetraodon lineatus

Impact assessment of Niger State fisheries legislation on fisheries conservation in Edozhigi local government area (L.G.A.) of Niger State

A preliminary survey was conducted among the fishermen in five selected villages in Edozhigi L.G.A. of Niger State. One hundred and fifty fishermen were randomly selected and interviewed to find out the impact of Niger State fisheries legislation on fisheries conservation resources in the area. The analysis of data collected using descriptive statistics indicated that undersized mesh of gill nets, beach seines and traps are being used unabated. Also, fenced barriers across the entrance of flood plain ponds and Ex-bow lakes from the main stream are in the area. The fisheries rules and regulations implementers are rarely seen or not seen at all in the area. The decreasing nature of fish catches was detected. It is observed that government policy on fish conversation is neglected due to inadequate or lack of funding for meaningful extension and implementation of the fisheries rules and regulations

An analysis of Nigerian freshwater fishes: those under threat and conservation options

The study assessed qualitatively the threat status of all nigerian freshwater fishes using such criteria as rarity, size at maturity, mode of reproduction, human population density, habitat degradation, pollution and range of each species among others. The biology of 48% (129n) of nigerian freshwater species is not well known. Of the 266 known freshwater fishes, 47 species represented 17% are critically endangered, 15 (5%) are endangered , 8(3%), are vulnerable while 23(8%) are near threatened. The paper suggests increased basic knowledge of threatened species and conservation policy along three lines public awareness, legislation and creation of national parks, aquaria and reserves as measures needed to ensure the conservation of the fishes

Small Indigenous Freshwater Fish Species: their Role in Poverty Alleviation, Food Security and Conservation of Biodiversity, 23-25 February 2010, Central Inland Fisheries Research Institute, Barrackpore, Kolkata, West Bengal. Workshop report

This is the report on the workshop on “Small Indigenous Freshwater Fish Species: Their Role in Poverty Alleviation, Food Security and Conservation of Biodiversity”, organized by the International Collective in Support of Fishworkers(ICSF) in collaboration with the Inland Fisheries Society of India (IFSI). The workshop was a forum for exchange of views on the role of small indigenous freshwater fish species (SIFFS) in enhancing rural food supply and livelihood security, and in conserving biodiversity. The workshop also discussed the socioeconomic and cultural contexts for the culture and capture of SIFFS, and how to enhance access—especially for women—to better incomes, livelihoods and nutritional security, through appropriate policy spaces. This report provides a fresh focus on SIFFS, usually regarded as ‘trash’ fish. It urges scientists, researchers and decisionmakers to develop policy and legislative measures to ensure the conservation and promotion of SIFFS, both in capture- and culture-fisheries systems. This report will be useful for fishworker organizations, researchers, policymakers, fish farmers, members of civil society and anyone interested in fisheries and livelihoods. (PDF contains 86 pages)