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

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.

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

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn207 ◽

2009 ◽

Vol 66 (1) ◽

pp. 101-108 ◽

Cited By ~ 27

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.

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Environmental Effects on Recruitment and Implications for Biological Reference Points of Eastern Baltic Cod (Gadus morhua)

Journal of Northwest Atlantic Fishery Science ◽

10.2960/j.v41.m636 ◽

2009 ◽

Vol 41 ◽

pp. 205-220 ◽

Cited By ~ 41

Author(s):

F W Köster ◽

M Vinther ◽

B R Mackenzie ◽

M Eero ◽

M Plikshs

Keyword(s):

Environmental Effects ◽

Gadus Morhua ◽

Reference Points ◽

Eastern Baltic ◽

Baltic Cod

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The abundance and patterns of the egg and larval spatial distribution of Eastern Baltic cod Gadus morhua callarias (Gadidae) in 1931–1996

Journal of Ichthyology ◽

10.1134/s0032945213020069 ◽

2013 ◽

Vol 53 (3) ◽

pp. 199-208 ◽

Cited By ~ 2

Author(s):

E. M. Karaseva

Keyword(s):

Spatial Distribution ◽

Gadus Morhua ◽

Eastern Baltic ◽

Baltic Cod

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Robustness of egg production methods as a fishery independent alternative to assess the Eastern Baltic cod stock (Gadus morhua callarias L.)

Fisheries Research ◽

10.1016/j.fishres.2011.01.024 ◽

2012 ◽

Vol 117-118 ◽

pp. 75-85 ◽

Cited By ~ 12

Author(s):

Gerd Kraus ◽

Hans-Harald Hinrichsen ◽

Rüdiger Voss ◽

Eske Teschner ◽

Jonna Tomkiewicz ◽

...

Keyword(s):

Egg Production ◽

Gadus Morhua ◽

Production Methods ◽

Eastern Baltic ◽

Baltic Cod

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Lack of recreational fishing compliance may compromise effectiveness of Rockfish Conservation Areas in British Columbia

10.31230/osf.io/cg6k9 ◽

2018 ◽

Author(s):

Dana Haggarty ◽

Steve J.D. Martell ◽

Jonathan B. Shurin

Keyword(s):

British Columbia ◽

Protected Areas ◽

Marine Protected Areas ◽

Fishing Effort ◽

Area Ratio ◽

Recreational Fishing ◽

Conservation Areas ◽

Fish Stocks ◽

Ecological Recovery ◽

Recovery Education

Compliance with spatial fishing regulations (e.g., marine protected areas, fishing closures) is one of the most important, yet rarely measured, determinants of ecological recovery. We used aerial observations of recreational fishing events from creel surveys before, during, and after 77 Rockfish Conservation Areas (RCAs) were established in British Columbia, Canada. There was no evidence of a change in fishing effort in 83% of the RCAs, and effort in five RCAs increased after establishment. Fishing effort in open areas adjacent to the RCAs declined with time and was higher than effort in the RCAs in all 3 years. Next, we used compliance data for 105 RCAs around Vancouver Island to model the drivers of compliance. Compliance was related to the level of fishing effort around the RCA, the size and perimeter-to-area ratio of RCAs, proximity to fishing lodges, and the level of enforcement. Noncompliance in RCAs may be hampering their effectiveness and impeding rockfish recovery. Education and enforcement efforts to reduce fishing effort inside protected areas are critical to the recovery of depleted fish stocks.

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Slave to the rhythm: seasonal signals in otolith microchemistry reveal age of eastern Baltic cod (Gadus morhua)

ICES Journal of Marine Science ◽

10.1093/icesjms/fsv247 ◽

2015 ◽

Vol 73 (4) ◽

pp. 1019-1032 ◽

Cited By ~ 6

Author(s):

K. Hüssy ◽

J. Gröger ◽

F. Heidemann ◽

H.-H. Hinrichsen ◽

L. Marohn

Keyword(s):

North Sea ◽

Gadus Morhua ◽

Statistical Significance ◽

Structural Break ◽

Age Determination ◽

Element Concentrations ◽

Visual Contrast ◽

Growth Zones ◽

Eastern Baltic ◽

Baltic Cod

Abstract Annual growth zones in cod otoliths from the eastern Baltic stock are less discrete than in other cod stocks leading to biased age reading, which recently led to a failure of age-based assessment in the eastern Baltic cod stock. In this study, we explored the applicability of minor and trace element patterns in cod otoliths for age determination. By first identifying elements of interest in a stock without ageing problems, western Baltic cod, we then tested their applicability on another stock without ageing problems, North Sea cod, and finally applied this knowledge to estimate age of eastern Baltic cod. In western Baltic cod, matching patterns with respect to occurrence of minima and maxima in both otolith opacity and element concentrations were found for Cu, Zn, and Rb, and inverse patterns with Mg and Mn. No match was found for Pb, Ba, and Sr. In the test stock, the North Sea cod, the same patterns in Cu, Zn, Rb, Mg, and Mn signals occurred. All eastern Baltic cod with low visual contrast between growth zones exhibited clearly defined synchronous cycles in Cu, Zn, Rb and Pb. Using a combined finite differencing method and structural break models approach, the statistical significance of the local profile minima were identified, based on which their age could be estimated. Despite extensive environmental differences between the three areas examined, the element concentrations of Cu, Zn, and Rb were strongly correlated in all individuals with similar correlations in all three areas, suggesting that the incorporation mechanisms are the same for these elements and independent of environmental concentrations.

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Egg production of Baltic cod (Gadus morhua) in relation to variable sex ratio, maturity, and fecundity

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-159 ◽

2002 ◽

Vol 59 (12) ◽

pp. 1908-1920 ◽

Cited By ~ 65

Author(s):

Gerd Kraus ◽

Jonna Tomkiewicz ◽

Friedrich W Köster

Keyword(s):

Sex Ratio ◽

Egg Production ◽

Gadus Morhua ◽

Reproductive Potential ◽

Relative Fecundity ◽

Spawning Stock ◽

Class Strength ◽

The Difference ◽

Eastern Baltic ◽

Baltic Cod

Observed fluctuations in relative fecundity of Eastern Baltic cod (Gadus morhua L.) were related to food availability during the main feeding period and were used to develop a predictive model that explained 72% of the interannual variations in fecundity. Time series of sex ratios, maturity ogives, and relative fecundity were combined with mean weights-at-age and stock sizes from an analytical multispecies model to estimate the potential egg production (PEP). Relationships between PEP and independent estimates of realized daily and seasonal egg production from egg surveys were highly significant. The difference between estimates of potential and realized seasonal egg production was of a magnitude corresponding to the expected loss of eggs as a result of atresia, fertilization failure, and early egg mortality. The removal of interannual variability in sex ratio, maturity, and fecundity on estimates of PEP deteriorated the relationships in all three cases. PEP proved to be superior to spawning stock biomass as measure of the reproductive potential in a stock-recruitment relationship of Eastern Baltic cod. PEP in combination with the reproductive volume explained 61% of the variation in year-class strength at age 2.

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Evaluating the ecological effects of Mediterranean marine protected areas: habitat, scale and the natural variability of ecosystems

Environmental Conservation ◽

10.1017/s0376892900000199 ◽

2000 ◽

Vol 27 (2) ◽

pp. 159-178 ◽

Cited By ~ 70

Author(s):

J.A. GARCÍA CHARTON ◽

I.D. WILLIAMS ◽

A. PÉREZ RUZAFA ◽

M. MILAZZO ◽

R. CHEMELLO ◽

...

Keyword(s):

Protected Areas ◽

Marine Protected Areas ◽

Multiple Scales ◽

Natural Variability ◽

Data Sets ◽

Nested Designs ◽

Spatio Temporal ◽

Habitat Scale ◽

Physical Elements

The capability to detect and predict the responses of marine populations and communities to the establishment of marine protected areas (MPAs) depends on the ability to distinguish between the influences of management and natural variability due to the effects of factors other than protection. Thus, it is important to understand and quantify the magnitude and range of this natural variability at each scale of observation. Here we review the scale of responses of target populations and communities to protection within Mediterranean MPAs, against their ‘normal’ spatio-temporal heterogeneity, and compare those with documented cases from other temperate and tropical marine ecosystems. Additionally, we approach the problem of the relative importance of habitat structure, considered as a set of biological and physical elements of the seascape hierarchically arranged in space at multiple scales, to drive natural variability. We conclude that much more effort has to be made to characterize heterogeneity in relation to Mediterranean MPAs, and to quantify and explain relationships between target species and their habitats as sources of such variability. These studies should be based on sound sampling designs, which (1) generate long-term data sets, and would ideally (2) be based on a Mediterranean-wide comparison of a number of protected and unprotected localities, (3) be designed from a multi-scaled perspective, and (4) control for factors other than protection, in order to avoid their confounding effects. The need for appropriate spatial and temporal replication, nested designs and power analysis is advocated.

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