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Many deep‐water fish populations, being k‐selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (M. dypterygia) and Mediterranean or Spanish ling (M. macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, in order to shed light on the challenges these deep water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which we analyze here has been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepatosomatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the Northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most of the populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the Northeastern Atlantic and the Mediterranean suggest that only some populations located in the north Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, our results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions., Sí

The Obligation of Sustainable Fisheries Management: Review of Endured Failures and Challenges in Exploitation of the Living Sea

The comparison of VIT model results with those of the virtual population analysis assessment of the cod stock in the Skagerrak, North Sea and Eastern Channel established by the International Council for the Exploration of the Sea (ICES) reveal that overall trends in fishing mortality and stock size are well captured over a period of three decades (1963-1992). However, the implications of the equilibrium assumption (steady state) made by the VIT model are enormous, as it forces strong inter-annual variations in the estimated fishing mortality, especially in years when the age composition shows strong year class effects. Estimated VIT output parameters should be carefully interpreted when the assessed stock suffers from reduction in abundance and high exploitation, as this condition is likely to deviate from steady state. The VIT estimates of the virgin stock biomass appear very variable, extremely high and fairly dependent on annual stock size estimates. Their use in fisheries management as a realistic biological stock biomass reference is not recommended. The VIT estimates of F0.1 and Fmax are found to be in line with the ICES estimates. Therefore, model results should allow qualitative conclusions regarding the status of marine living resources in relation to a target reference of exploitation rate. Quantitative conclusions regarding the assessment of the exploitation status are only recommended when the model is applied to short time series of consecutive annual data and the resulting variation in the estimated stock parameters appears reasonably low. As such, the model results may form the basis for scientifically sound fisheries management advice covering the actual state of the stock as well as medium-term forecasts of catch and biomass under different options., Las comparaciones de los resultados del modelo VITcon los del método de VPA, empleado para la evaluación del stock de bacalao en el Skagerrak, Mar del Norte y la parte oriental del Canal de la Mancha, muestran que las tendencias generales de la mortalidad por pesca y del tamaño del stock aparecen bien representadas en un período de tres décadas (1963-1992). No obstante las implicaciones de la asunción de equilibrio (estado estacionario) del modelo VITson muy grandes y fuerzan importantes variaciones interanuales de la mortalidad por pesca, especialmente en aquellos años en que la composición de edades muestra el efecto de clases anuales fuertes. Los parámetros estimados por VIT deben ser cuidadosamente interpretados cuando el stock evaluado presenta una fuerte reducción de su abundancia y una elevada explotación ya que esta condición lo aleja del estado estacionario. Las estimaciones de la biomasa virgen son muy variables, extremadamente altas y dependientes de las estimaciones del stock. No se recomienda su uso como punto de referencia de una biomasa realista en un contexto de gestión pesquera. Las estimaciones de F0.1 y Fmax son similares a las estimaciones de ICES. Los resultados del modelo permiten la obtención de conclusiones más bien cualitativas sobre el estado de los recursos marinos en referencia a la tasa de explotación. Las conclusiones cuantitativas sobre la evaluación del estado de explotación son recomendables solamente en el caso de que se aplique el modelo a una serie corta de datos anuales consecutivos y cuando la variación de los parámetros estimados sea razonablemente baja. Los resultados del modelo pueden fundamentar las bases de un correcto asesoramiento del estado real del stock así como predicciones de biomasa, bajo diversas alternativas de gestión, a corto y medio plazo.

The cod stock in the Western Baltic Sea is assessed to be overfished regarding the definitions of the UN World Summit on Sustainable Development at Johannesburg in 2002. Thus, the European Fisheries Council enforced a multi-annual management plan in 2007. Our medium term simulations over the future 10 years assume similar stock productivity as compared with the past four decades and indicate that the goals of the management plan can be achieved through TAC and consistent effort regulations. Taking account of the uncertainty in the recruitment patterns, the target average fishing mortality of age groups 3 – 6 years of F = 0.6 per year as defined in the management plan is indicated to exceed sustainable levels consistent with high long term yields and low risk of depletion. The stipulated constraint of the annual TAC variations of ±15% will dominate future fisheries management and implies a high recovery potential of the stock through continued reductions in fishing mortality. The scientific assessment of sustainable levels of exploitation and consideration in the plan is stronglyadvised, taking account of uncertainties attributed to environmental and biological effects. We recommend our study to be complemented with economic impact assessments including effects on by-catch species, which have been disregarded in this study. It is further demonstrated, that the goals of the management plan can alternatively be achieved by mesh size adaptations. An alternative technical option of mesh size increases to realize the required reductions in fishing mortality provides avoidance of discards of undersized fish after a few years by means of improved selectivity, another important element of the Common Fisheries Policy. However, it is emphasized that technical regulations since 1990 failed to affect the by-catch and discards of juvenile cod. In any way, the meaningful implementation of the multiannual management plan through stringent control and enforcement appears critical. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung - Information Fishery research in 2010. European Commission, Joint Research Centre, Institute for Protection and Security of the Citizen, Maritime Affairs Unit G.04; Johann Heinrich von Thünen-Institut, Institut für Seefischerei; Johann Heinrich von Thünen-Institut, Institut für Ostseefischerei

The pressure of users other than shipping and fishery on the national EEZs for territorial claims has increased in recent years. So it becomes necessary to carry out a spatial planning for which all users have to indicate their recent and planned future activities. For the German waters in the North Sea a first attempt was made to calculate the mean international landings for the commercially important fish and crustacean species on the spatial scale of ICES-rectangles. The relationships between the German and international landings per species are listed in a table and the distribution of the landings for each species within the area are shown in 13 figures. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung - Information Fishery Research in 2010. Johann Heinrich von Thünen-Institut, Institut für Seefischerei

Cod, haddock, whiting, saithe, plaice, sole and Norway lobster are 7 main target species of the demersal mixed fisheries in the North Sea, Skagerrak and Eastern Channel. Gadoids and Norway lobsters are mainly taken in the nor-thern North Sea by towed gears except beam trawls while the flatfish fisheries are conducted in the southern North Sea mainly using beam trawls. Recently, the central North Sea appears less fished by demersal gears. Towed nets including seines and beam trawls equipped with meshes of more than 100 mm resp. more than 80 mm were identified as the main gears effecting the depleted cod and reduced plaice stocks. The saithe sector, using towed nets with meshes of more than110 mm, longlines, gill nets and others, appears to affect the 7 species to a lesser extend. These results support the interim effort limitations by gear types, vessel and month as enforced by the European Commission since 2003. TAC regulations alone are considered inefficient to sustainably harvest stocks by mixed fisheries. A fleet-effort management method is developed estimating the fleets’ effects based on the sum of partial exploitation rates of the species in mixed fisheries weighted by the ratio of the precautionary reference Bpa and the actual SSB size as ecological quality objective. Applying such fleet effort management could result in increased catch possibilities of some stocks by fleets selecting mainly few and non-overexploited stocks while respecting precautionary management constraints in minimum SSB or maximum exploitation rates at the same time. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.

The European Commission has claimed a fundamental revision of the European Common Fisheries Policy in its Green Paper (EC 2001) by highlighting the reasons of continued overfishing of a number of valuable demersal fish stocks. Quotas in excess of scientific recommendations, fleet over capacities and poor enforcement of management decisions were identified causal for major stock and yield reductions while gaps in scientific advices were also criticized. The depleted cod stock in the North Sea, Skagerrak and Eastern Channel is the most prominent example. Existing and proposed management regulations were analysed by an expert group which met with fishing industry consultations in Brussels during 28 April – 7 May 2003. Depending on compliance with new technical regulations since 2000, the cod stock and its exploitation was found only marginally effected, while whiting displayed immediately significant losses in yield over long term and short term losses in haddock yields were reversed in substantial gains, also in SSB. However, reduction in fishing effort was found more effective in recovery potential than technical changes including closed areas, for which detailed information about variation in distribution of the stocks and the fisheries are required. Such effort reductions would reduce not only landings but also unregulated discarding, which is believed to be a major reason of the failure of the management measures in mixed fisheries. Recent trends in fishing effort of European fleets could not be quantified due to persistent data deficiencies. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.

Since 1999, the ICES Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak assesses the saithe stock in the North Sea, Skagerrak and west of Scotland as a single stock unit. The sampling, evaluation and role of biological data from the German saithe fishery in the assessment are described. The German data showed similar trends as observed in French and Norwegian series. Based on these estimates, the spawning stock recovered to more than 200 000 t due to reductions in quotas and exploitation rates. Thus, the production of the stock increased also in combination with good recruitment and positive trends in spawning stock size and landings were projected for 2002. The biological data derived from the German saithe fishery dominated the assessment of stock size, structure and exploitation. This fact encourages a continuation of the described analyses based on sampling onboard fishing vessels and fish markets by the Institute for Sea Fisheries. The successful collaboration with the saithe fishing industry is judged as an important contribution to the sustainable management of fish stocks. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.

A comparative analysis of the fish condition (Fulton’s K) of 11 cod stocks in the North Atlantic in relation to the temperature of their habitat and their reproductive potential is presented. It is shown that the cod stocks in the North Atlantic display different levels of mean condition, which are partly due to the different temperature regimes of their habitats. Cod stocks living in colder waters, e.g. Southern Gulf of St Lawrence, Greenland and Grand Bank cod stocks, were more poorly-conditioned than cod stocks living in warmer waters, e.g. North Sea and Irish Sea. The a-coefficient obtained from a standardised Ricker’s recruitment-spawning stock biomass (SSB) relationship represents the function’s slope at the origin and was defined as an indicator for the recruitment potential of a given stock. The a-coefficients were found to be correlated with the mean condition factors of the stocks in 9 of the 11 cod stocks analysed. This indicates that stocks consisting of poorly-conditioned individuals appear to be very susceptible to reduced recruitment at low SSB, while the stocks which consist of well conditioned fish seem to behave more robust with a higher probability of good recruitment at low SSB. The positive effect of the cod condition on their reproductive potential generally implies that the well-conditioned stocks in the Northeast Atlantic can sustain higher exploitation rates than the poorly-conditioned stocks in the Northwest Atlantic. This implication is confirmed by a positive relationship between the estimated biological management reference points Fmed and the mean cod condition factors of the stocks.

Recently, the German redfish fishery displayed a pronouncedseasonal 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. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.

6 pages, 2 figures, 1 table, Based on recent studies wich highling the dominating influence of the North Atlantic Oscillation (NAO) on climatic changes in the North Atlantic Ocean, and their potential influences on biotic processes in the ocean, the paper analyses existing time series of recuitment of cod (Gadus morhua) off Greenland, air temperatures of Nuuk/West Greenland,... [...]

7 pages, 7 figures, 3 tables, Based on reasonable relations between recuitment, spawing stocks biomass, and temperature, stock developments were simulated under different conventionally applied management reference points in order to investigate their applicability. [...]

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. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.

At present, the severe decline of the fishery off Greenland is being discussed controversially. In contrast to overfishing, climate changes and emigration are itemized causal. Available German data on commercial catches and research cruises are presented for clarification. A few years after the beginning of heavy exploitation during the early sixties, the stocks of cod, golden and beaked redfish reflected a significant rejuvenescence based on catch analysis. Regular scientific surveys• for stock assessment purposes commenced in 1982 when the productivity of the stocks was already adversely affected due to low spawning stocks and extremely irregular recruitment. From this point of view, the results of the latest survey in 1995 showing stagnant fish biomass at record low level since 1991 are not surprising. The status of the cod stock is still considered severely depleted. Taking the high abundance of juvenile redfish into account, recovery of the groundfish stocks is unlikely in short term and depends on the non-predictable recruitment only. Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.

Since 1991, the aggregate biomass of fish stocks inhabiting the West Greenland shelf stagnates at the lowest level. The latest survey results of cruise no. 152 conducted by FRV 'Walther Herwig III' do not indicate any improvements in state of the stocks, although no fishing effort was recently directed towards groundfish. The cod stock showed again a record low and is presently dominated by recruitsof the year classes 1991 and 1993. Both year classes are considered to be weak and the cod stock is beyond the 'minimum biologically acceptable level'. Consequently, an increase in stock abundance is not expected either in short or long term. Other ecologically or economically important fish species, American plaice, redfish, wolffish and starry skate, were also found to have minimum stock abundances. By-catch estimates of juvenile groundfish taken by the shrimp fishery, operating at traditional grounds of cod and redfish fisheries, are indispensible. Analysis of climatological data from Nuuk/West Greenland indicates that climate during the past fourty years was characterized by two decades of anomalous warm conditions, and cooling whichdominates the dimate since 1969. Anomalous cold events were encountered during 1983, 1984 and during 1992, 1993. Similar to the air temperature anomalies, autumn temperatures of the ocean surface layer indicate cold and warm periods during the past thirty years. In contrast to the colder than normal atmospheric conditions during the early nineties, however, the ocean conditions indicateintermediate warming. Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010

Die gravierenden Änderungen in der Produktivität der westgrönländischen Fischbestände, die in der jüngsten Vergangenheit zu erheblichen Ertragseinbußen führten, scheinen im wesentlichen von den Rekrutierungsprozessen des Kabeljau und den fischereilichen Aktivitäten gesteuert zu sein. Ein multiplikatives Produktionsmodell, das allein auf der Anzahl der dreijährigen Rekruten und dem geleisteten Fischereiaufwand basiert, erklärt 87 % der gemessenen Variabilität und prognostiziert für 1994 bei minimalem Aufwand auf niedrigstem Niveau stagnierende Bestandsgrößen. Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fischery research in 2010

Nach dem Zusammenbruch der Kabeljaufischerei vor Westgrönland im Jahre 1990 erreichte der Bestand im Herbst 1991 seine geringste Bestandsgröße seit 1982. Im Vergleich zum Vorjahr verringerte sich der Bestand bis zum Dezember 1992 nochmals deutlich. Das regelmäßige aber geringe Vorkommen von Jungfischen deutet auf eine nur mäßige Rekrutierung. Einige ökologisch wichtige aber fischereilich nicht interessante Fischarten weisen auf niedrigem Niveau stagnierende oder schwach zunehmende Bestandszahlen auf. Die Einrichtung umfassender Schonmaßnahmen für den Kabeljau erscheint dringend geboten. Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010

Die Kenntnisse über die wichtigsten Merkmale der Biologie der 5 Rotbarscharten des Nordatlantiks für die bewirtschaftung ihrer Bestände werden kurz dargestellt und die historischen und rezenten Entwicklungen der Fanggerträge von 8 für die deutsche Fischwirtschaft bedeutungsvollen Rotbarschbestände beschrieben. Mögliche Schwerpunkte der künftigen Rotbarschforschung durch das Institut für Seefischerei werden unter Berücksichtigung der Schwirigkeiten bei der Identifizierung der Arten, der Berechnung der Wachstumsraten und der Abschätzung der Rekrutierungsprozesse diskutiert. Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010

Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010

Johann Heinrich von Thünen-Institut, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010