scholarly journals Identifying eastern Baltic cod nursery grounds using hydrodynamic modelling: knowledge for the design of Marine Protected Areas

2009 ◽  
Vol 66 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Hans-Harald Hinrichsen ◽  
Gerd Kraus ◽  
Uwe Böttcher ◽  
Fritz Köster
Keyword(s):  
Baltic Sea ◽  
Protected Areas ◽  
Marine Protected Areas ◽  
Dynamic Models ◽  
Hydrodynamic Modelling ◽  
Atmospheric Conditions ◽  
Decadal Climate Variability ◽  
Nursery Grounds ◽  
Eastern Baltic ◽  
Baltic Cod

Abstract Hinrichsen, H-H., Kraus, G., Böttcher, U., and Köster, F. 2009. Identifying eastern Baltic cod nursery grounds using hydrodynamic modelling: knowledge for the design of Marine Protected Areas. – ICES Journal of Marine Science, 66: 101–108. Knowledge of the spatial and temporal distribution of juvenile cod is essential to closing the life cycle in population dynamic models, and it is a prerequisite for the design of Marine Protected Areas (MPAs) aiming at the protection of juveniles. In this study, we use a hydrodynamic model to examine the spatial distribution of eastern Baltic cod larvae and early juveniles. The transport patterns of the larvae spawned at the three major spawning grounds in the central Baltic Sea were investigated by drift model simulations for the period 1979–2004. We analysed potential habitats for their suitability for juvenile settlement, i.e. the change from pelagic to demersal life. The results revealed a clear dependence of the probability for successful settling on wind-induced drift of larval cod, which is controlled by the local atmospheric conditions over the Baltic Sea. Furthermore, we found evidence that the final destinations of juvenile cod drift routes are affected by decadal climate variability. Application of the methodology to MPA design is discussed, e.g. identifying the overlap of areas with a high probability of successful juvenile cod settlement and regions of high fishing effort in small-meshed fisheries targeting sprat and herring.

scholarly journals A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.)

2008 ◽  
Vol 66 (1) ◽  
pp. 109-121 ◽  
Author(s):  
Gerd Kraus ◽  
Dominique Pelletier ◽  
Julien Dubreuil ◽  
Christian Möllmann ◽  
Hans-Harald Hinrichsen ◽  
...  
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Gadus Morhua ◽  
Environmental Variability ◽  
Fishing Effort ◽  
Biological Knowledge ◽  
Model Based ◽  
Spatio Temporal ◽  
Eastern Baltic ◽  
Baltic Cod

Abstract Kraus, G., Pelletier, D., Dubreuil, J., Möllmann, C., Hinrichsen, H-H., Bastardie, F., Vermard, Y., and Mahévas, S. 2009. A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.). – ICES Journal of Marine Science, 66: 109–121. The eastern Baltic cod stock collapsed as a consequence of climate-driven adverse hydrographic conditions and overfishing and has remained at historically low levels. Spatio-temporal fishing closures [Marine Protected Areas (MPAs)] have been implemented since 1995, to protect and restore the spawning stock. However, no signs of recovery have been observed yet, either suggesting that MPAs are an inappropriate management measure or pointing towards suboptimal closure design. We used the spatially explicit fishery simulation model ISIS-Fish to evaluate proposed and implemented fishery closures, combining an age-structured population module with a multifleet exploitation module and a management module in a single model environment. The model is parameterized based on (i) the large amount of biological knowledge available for cod and (ii) an analysis of existing spatially disaggregated fishery data. As the population dynamics of eastern Baltic cod depend strongly on the climate-driven hydrographic regime, we considered two production regimes of the stock. MPAs were only effective for stock recovery when they reduced overall fishing effort. The performance of MPAs needs to be evaluated relative to environmental regimes, especially for stocks facing strong environmental variability.

scholarly journals Models and indicators for assessing conservation and fisheries-related effects of marine protected areas

2008 ◽  
Vol 65 (4) ◽  
pp. 765-779 ◽  
Author(s):  
Dominique Pelletier ◽  
Joachim Claudet ◽  
Jocelyne Ferraris ◽  
Lisandro Benedetti-Cecchi ◽  
José Antonio Garcìa-Charton
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Statistical Models ◽  
Dynamic Models ◽  
Statistical Modelling ◽  
Recent Developments ◽  
Management Policies ◽  
The Impact ◽  
Support Decision Making ◽  
Dynamics Of Populations

Two kinds of approaches have been used for assessing conservation and fisheries-related effects of marine protected areas (MPAs): (i) statistical modelling based on field data and (ii) mathematical modelling quantifying the consequences of MPAs on the dynamics of populations, communities, and fisheries. Statistical models provide a diagnostic on the impact of MPAs on the ecosystem and resources; they are also needed for devising and assessing sampling designs for monitoring programs. Dynamic models enable exploration of the consequences of MPA designs and other management policies. We briefly review how each of these approaches has been implemented up to now in the literature and identify potential indicators of MPA effects that can be obtained from each approach to provide scientific advice for managers. Methodological gaps that impede the assessment of MPA effects and the construction of appropriate indicators are then discussed, and recent developments in this respect are presented. We finally propose ways to reconcile the two approaches based on their complementarity to derive suitable indicators to support decision making. In this respect, we suggest in addition that MPA managers should be associated from the beginning to the design and construction of indicators.

scholarly journals Changes in population depth distribution and oxygen stratification are involved in the current low condition of the eastern Baltic Sea cod (<i>Gadus morhua</i>)

2021 ◽  
Vol 18 (4) ◽  
pp. 1321-1331
Author(s):  
Michele Casini ◽  
Martin Hansson ◽  
Alessandro Orio ◽  
Karin Limburg
Keyword(s):  
Baltic Sea ◽  
Body Condition ◽  
Gadus Morhua ◽  
Depth Distribution ◽  
Low Oxygen ◽  
Commercial Fish ◽  
Spatial Overlap ◽  
The Past ◽  
Eastern Baltic ◽  
Baltic Cod

Abstract. During the past 20 years, hypoxic areas have expanded rapidly in the Baltic Sea, which has become one of the largest marine “dead zones” in the world. At the same time, the most important commercial fish population of the region, the eastern Baltic cod, has experienced a drastic reduction in mean body condition, but the processes behind the relation between deoxygenation and condition remain elusive. Here we use extensive long-term monitoring data on cod biology and distribution as well as on hydrological variations to investigate the processes that relate deoxygenation and cod condition during the autumn season. Our results show that the depth distribution of cod has increased during the past 4 decades at the same time of the expansion, and shallowing, of waters with oxygen concentrations detrimental to cod performance. This has resulted in a progressively increasing spatial overlap between the cod population and low-oxygenated waters after the mid-1990s. This spatial overlap and the actual oxygen concentration experienced by cod therein statistically explained a large proportion of the changes in cod condition over the years. These results complement previous analyses on fish otolith microchemistry that also revealed that since the mid-1990s, cod individuals with low condition were exposed to low-oxygen waters during their life. This study helps to shed light on the processes that have led to a decline of the eastern Baltic cod body condition, which can aid the management of this population currently in distress. Further studies should focus on understanding why the cod population has moved to deeper waters in autumn and on analyzing the overlap with low-oxygen waters in other seasons to quantify the potential effects of the variations in physical properties on cod biology throughout the year.

Fishermen responses on marine protected areas in the Baltic cod fishery

Marine Policy ◽  
2010 ◽  
Vol 34 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Petri Suuronen ◽  
Pekka Jounela ◽  
Vesa Tschernij
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
The Baltic ◽  
Baltic Cod

scholarly journals Ecological coherence of Marine Protected Areas: New tools applied to the Baltic Sea network

2020 ◽  
Vol 30 (4) ◽  
pp. 743-760 ◽  
Author(s):  
Per R. Jonsson ◽  
Per‐Olav Moksnes ◽  
Hanna Corell ◽  
Erik Bonsdorff ◽  
Martin Nilsson Jacobi
Keyword(s):  
Baltic Sea ◽  
Protected Areas ◽  
Marine Protected Areas ◽  
The Baltic Sea ◽  
The Baltic ◽  
Ecological Coherence

scholarly journals Climate-driven long-term trends in Baltic Sea oxygen concentrations and the potential consequences for eastern Baltic cod (Gadus morhua)

2011 ◽  
Vol 68 (10) ◽  
pp. 2019-2028 ◽  
Author(s):  
Hans-Harald Hinrichsen ◽  
Bastian Huwer ◽  
Andrejs Makarchouk ◽  
Christoph Petereit ◽  
Matthias Schaber ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Field Data ◽  
Gadus Morhua ◽  
The Baltic Sea ◽  
Oxygen Conditions ◽  
Long Term Trends ◽  
The Baltic ◽  
Eastern Baltic ◽  
Baltic Cod

Abstract Hinrichsen, H-H., Huwer, B., Makarchouk, A., Petereit, C., Schaber, M., and Voss, R. 2011. Climate-driven long-term trends in Baltic Sea oxygen concentrations and the potential consequences for eastern Baltic cod (Gadus morhua). – ICES Journal of Marine Science, 68: 2019–2028. Variations in oxygen conditions in the Baltic are influenced by several mechanisms. Generally, the frequency and magnitude of major inflows have been identified as the most crucial process for the renewal of oxygen-depleted water masses in the Baltic Sea. Furthermore, enhanced degradation of suspended organic matter by bacteria over the past few decades has increased oxygen consumption. Finally, the effects of large-scale climate warming are causing long-term variations in oxygen content and saturation as an observed increase in temperature has led to a general decrease in oxygen solubility of water masses. Oxygen-dependent relationships based on field data and laboratory experiments were used to analyse the impact of the observed decrease in oxygen content on eastern Baltic cod (Gadus morhua) stock-specific processes (e.g. survival rates of eggs, settlement probability of juveniles, habitat utilization of spawning fish, age structure of successful spawners, food consumption rates of adult fish). The observed long-term decline in oxygen conditions in the Baltic Sea has had a seemingly generally negative impact on oxygen-related processes for the different life stages of eastern Baltic cod. Experimentally derived results of oxygen-driven processes were validated by field data.

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