scholarly journals Recruitment failure of coastal predatory fish in the Baltic Sea coincident with an offshore ecosystem regime shift

2010 ◽  
Vol 67 (8) ◽  
pp. 1587-1595 ◽  
Author(s):  
Lars Ljunggren ◽  
Alfred Sandström ◽  
Ulf Bergström ◽  
Johanna Mattila ◽  
Antti Lappalainen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Regime Shift ◽  
Early Stage ◽  
Food Limitation ◽  
Zooplankton Biomass ◽  
Predatory Fish ◽  
Zooplankton Abundance ◽  
The Baltic Sea ◽  
Recruitment Failure ◽  
The Baltic

Abstract Ljunggren, L., Sandström, A., Bergström, U., Mattila, J., Lappalainen, A., Johansson, G., Sundblad, G., Casini, M., Kaljuste, O., and Eriksson, B. K. 2010. Recruitment failure of coastal predatory fish in the Baltic Sea coincident with an offshore ecosystem regime shift. – ICES Journal of Marine Science, 67: 1587–1595. The dominant coastal predatory fish in the southwestern Baltic Sea, perch and pike, have decreased markedly in abundance during the past decade. An investigation into their recruitment at 135 coastal sites showed that both species suffered from recruitment failures, mainly in open coastal areas. A detailed study of 15 sites showed that areas with recruitment problems were also notable for mortality of early-stage larvae at the onset of exogenous food-intake. At those sites, zooplankton abundance predicted 83 and 34% of the variation in young of the year perch and pike, respectively, suggesting that the declines were caused by recruitment failure attributable to zooplankton food limitation. Incidences of recruitment failure match in time an offshore trophic cascade that generated massive increases in planktivorous sprat and decreases in zooplankton biomass in the early 1990s. Therefore, sprat biomass explained 53% of the variation in perch recruitment from 1994 to 2007 at an open coastal site, where three-spined stickleback also increased exponentially after 2002. The results indicate that the dramatic change in the offshore ecosystem may have propagated to the coast causing declines of the dominating coastal predators perch and pike followed by an increase in the abundance of small-bodied fish.

Effects of Climate Change and Fisheries on the Marine Ecosystem of the Baltic Sea

2019 ◽  
Author(s):  
Christian Möllmann
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regime Shift ◽  
Sea Water ◽  
Marine Ecosystem ◽  
Trophic Levels ◽  
Ecosystem Structure ◽  
The Baltic Sea ◽  
Recruitment Failure ◽  
The Baltic

Climate change and fisheries have significantly changed the Baltic Sea ecosystem, with the demise of Eastern Baltic cod (Gadus morhua callarias) being the signature development. Cod in the Central Baltic Sea collapsed in the late 1980s as a result of low reproductive success and overfishing. Low recruitment and hence small year-classes were not able to compensate for fishing pressures far above sustainable levels. Recruitment failure can be mainly related to the absence of North Sea water inflows to the Central Baltic deep basins. These major Baltic inflows (MBIs) occurred regularly until the 1980s, when their frequency decreased to a decadal pattern, a development attributed to changes in atmospheric circulation patterns. MBIs are needed for ventilation of otherwise stagnating Baltic deep waters, and their absence caused reduced oxygen and salinity levels in cod-spawning habitats, limiting egg and larval survival. Climate change, on the other hand, has promoted a warmer environment richer in zooplanktonic food for larval Baltic sprat (Sprattus sprattus). Resulting large year-classes and low predation by the collapsed cod stock caused an outburst of the sprat stock that cascaded down to the zoo- and phytoplankton trophic levels. Furthermore, a large sprat population controlled cod recruitment and hence hindered a recovery of the stock by predation on cod eggs, limiting cod larval food supply. The change in ecosystem structure and function caused by the collapse of the cod stock was a major part and driver of an ecosystem regime shift in the Central Baltic Sea during the period 1988 to 1993. This reorganization of ecosystem structure involved all trophic levels from piscivorous and planktivorous fish to zoo- and phytoplankton. The observed large-scale ecosystem changes displayed the characteristics of a discontinuous regime shift, initiated by climate-induced changes in the abiotic environment and stabilized by feedback loops in the food web. Discontinuous changes such as regime shifts are characteristically difficult to reverse, and the Baltic ecosystem recently rather shows signs of increasing ecological novelty for which the failed recovery of the cod stock despite a reduction in fishing pressure is a clear symptom. Unusually widespread deficient oxygen conditions in major cod-spawning areas have altered the overall productivity of the population by negatively affecting growth and recruitment. Eutrophication as a consequence of intensive agriculture is the main driver for anoxia in the Baltic Sea amplified by the effects on continuing climate change and stabilized by self-enforcing feedbacks. Developing ecological novelty in the Baltic Sea hence requires true cross-sectoral ecosystem-based management approaches that truly integrate eutrophication combatment, species conservation, and living resources management.

Stickleback increase in the Baltic Sea – A thorny issue for coastal predatory fish

2015 ◽  
Vol 163 ◽  
pp. 134-142 ◽  
Author(s):  
Ulf Bergström ◽  
Jens Olsson ◽  
Michele Casini ◽  
Britas Klemens Eriksson ◽  
Ronny Fredriksson ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Predatory Fish ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Hypoxic areas, density-dependence and food limitation drive the body condition of a heavily exploited marine fish predator

2016 ◽  
Vol 3 (10) ◽  
pp. 160416 ◽  
Author(s):  
Michele Casini ◽  
Filip Käll ◽  
Martin Hansson ◽  
Maris Plikshs ◽  
Tatjana Baranova ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Density Dependence ◽  
Body Condition ◽  
Food Limitation ◽  
Biological Data ◽  
The Body ◽  
The Baltic Sea ◽  
Fish Predator ◽  
The Past ◽  
The Baltic

Investigating the factors regulating fish condition is crucial in ecology and the management of exploited fish populations. The body condition of cod ( Gadus morhua ) in the Baltic Sea has dramatically decreased during the past two decades, with large implications for the fishery relying on this resource. Here, we statistically investigated the potential drivers of the Baltic cod condition during the past 40 years using newly compiled fishery-independent biological data and hydrological observations. We evidenced a combination of different factors operating before and after the ecological regime shift that occurred in the Baltic Sea in the early 1990s. The changes in cod condition related to feeding opportunities, driven either by density-dependence or food limitation, along the whole period investigated and to the fivefold increase in the extent of hypoxic areas in the most recent 20 years. Hypoxic areas can act on cod condition through different mechanisms related directly to species physiology, or indirectly to behaviour and trophic interactions. Our analyses found statistical evidence for an effect of the hypoxia-induced habitat compression on cod condition possibly operating via crowding and density-dependent processes. These results furnish novel insights into the population dynamics of Baltic Sea cod that can aid the management of this currently threatened population.

ECOLOGICAL EFFECTS OF OIL VERSUS OIL PLUS DISPERSANT ON THE LITTORAL ECOSYSTEM OF THE BALTIC SEA

1985 ◽  
Vol 1985 (1) ◽  
pp. 485-490 ◽  
Author(s):  
O. Linden ◽  
A. Rosemarin ◽  
A. Lindskog ◽  
C. Hoglund ◽  
S. Johansson
Keyword(s):  
Baltic Sea ◽  
Oil Spill ◽  
Heterotrophic Bacteria ◽  
Benthic Fauna ◽  
Zooplankton Abundance ◽  
Total Production ◽  
Normal Numbers ◽  
The Baltic Sea ◽  
Blue Mussels ◽  
The Baltic

ABSTRACT The effects of a North Sea oil with or without the addition of dispersant were studied in a model of the littoral ecosystem of the Baltic Sea. Experiments were carried out in six pools with a volume of 8 m3 each, with flowthrough seawater and an ecosystem of the shallow rocky Baltic archipelago. All major fauna and flora were transferred into the pools in normal numbers and proportions. Two of the pools were exposed to oil alone. The amount of oil was equivalent to 20 ppm assuming total mixture. Two other pools were exposed to the same amount of oil and an oil dispersant (Corexit 9550, Exxon), and two pools served as controls. The effects studied were those on abundance of heterotrophic bacteria, periphyton photosynthesis, growth of bladder wrack, phytoplankton growth, zooplankton abundance and diversity, benthic fauna, physiological responses of certain crustaceans and molluscs, and the growth of blue mussels. In addition, the total photosynthesis and respiration of the ecosystem was studied. Concentrations of oil in water and in blue mussels were monitored. The experiments showed that almost all the measured parameters were affected. When comparing the effects between the pools, several of the results indicated a stronger response for oil alone compared to oil and dispersant. This was particularly obvious when monitoring the total production and respiration of the ecosystems. The explanation may be that the ecosystems in the pools exposed to oil and dispersant were exposed less time compared to those in the pools where oil alone was added. The oil and dispersant mixture obviously left the system much faster due to the water exchange compared to the oil without dispersant. In the latter case the oil adhered to surfaces and detritus and thus tended to stay longer in the environment. These results may provide valuable information for decision makers faced with an oil spill in shallow waters and who have an option to use oil spill dispersant.

scholarly journals Ecosystem-based management and the wealth of ecosystems

2017 ◽  
Vol 114 (25) ◽  
pp. 6539-6544 ◽  
Author(s):  
Seong Do Yun ◽  
Barbara Hutniczak ◽  
Joshua K. Abbott ◽  
Eli P. Fenichel
Keyword(s):  
Baltic Sea ◽  
Natural Capital ◽  
Shadow Price ◽  
Market Value ◽  
Wealth Index ◽  
Predatory Fish ◽  
Shadow Prices ◽  
The Baltic Sea ◽  
Ecosystem Based Management ◽  
The Baltic

We merge inclusive wealth theory with ecosystem-based management (EBM) to address two challenges in the science of sustainable management of ecosystems. First, we generalize natural capital theory to approximate realized shadow prices for multiple interacting natural capital stocks (species) making up an ecosystem. These prices enable ecosystem components to be better included in wealth-based sustainability measures. We show that ecosystems are best envisioned as portfolios of assets, where the portfolio’s performance depends on the performance of the underlying assets influenced by their interactions. Second, changes in ecosystem wealth provide an attractive headline index for EBM, regardless of whether ecosystem wealth is ultimately included in a broader wealth index. We apply our approach to the Baltic Sea ecosystem, focusing on the interacting community of three commercially important fish species: cod, herring, and sprat. Our results incorporate supporting services embodied in the shadow price of a species through its trophic interactions. Prey fish have greater shadow prices than expected based on market value, and predatory fish have lower shadow prices than expected based on market value. These results are because correctly measured shadow prices reflect interdependence and limits to substitution. We project that ecosystem wealth in the Baltic Sea fishery ecosystem generally increases conditional on the EBM-inspired multispecies maximum sustainable yield management beginning in 2017, whereas continuing the current single-species management generally results in declining wealth.

scholarly journals Regime shift in sea-ice characteristics and impact on the spring bloom in the Baltic Sea

Oceanologia ◽  
2021 ◽  
Author(s):  
Ove Pärn ◽  
René Friedland ◽  
Jevgeni Rjazin ◽  
Adolf Stips
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Regime Shift ◽  
Spring Bloom ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Determining the Regime Shift of the Baltic Sea Ice Seasons during 1982–2016

Naše more ◽  
2020 ◽  
Vol 67 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Jevgeni Rjazin ◽  
◽  
Ove Parn
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Regime Shift ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Past and Current Trends of Coastal Predatory Fish in the Baltic Sea with a Focus on Perch, Pike, and Pikeperch

Fishes ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 7 ◽  
Author(s):  
Jens Olsson
Keyword(s):  
Baltic Sea ◽  
Species Interactions ◽  
Current Data ◽  
Predatory Fish ◽  
The Baltic Sea ◽  
Current Trends ◽  
Impacting Factors ◽  
Past Data ◽  
The Baltic ◽  
And Function

Coastal predatory fish are of key importance for the provisioning of ecosystem services in the Baltic Sea. Worldwide, however, there has been a general and sharp decline in predatory fish populations, in turn threatening the viability and function of marine ecosystems. On the basis of the literature, the past (data until the 2000s) and current (data until early and mid 2010s) trends in abundance of coastal predatory fish in the Baltic Sea are reviewed in this paper. Potentially important impacting factors behind the temporal development of the populations and measures to strengthen and restore them are also discussed. Available data from coastal fish monitoring programs suggest a stable or increasing abundance of coastal predatory fish as a functional group and for the species perch in the majority of areas assessed in the Baltic Sea. For pike and pikeperch, data to support assessments is scarce, but suggest substantial declines in the abundance of both species in most assessed areas. The impacting factors behind these patterns vary between species and areas, but include climate, habitat exploitation, fishing, and species-interactions in the coastal food web. Measures to restore and support coastal predatory fish communities should follow an ecosystem-based approach to management and include efforts to regulate fisheries sectors in combination with habitat protection and restoration.

scholarly journals Predicting the effects of eutrophication mitigation on predatory fish biomass and the value of recreational fisheries

AMBIO ◽  
2019 ◽  
Vol 49 (5) ◽  
pp. 1090-1099 ◽  
Author(s):  
Göran Sundblad ◽  
Lena Bergström ◽  
Tore Söderqvist ◽  
Ulf Bergström
Keyword(s):  
Baltic Sea ◽  
Action Plan ◽  
Water Clarity ◽  
Ecological Modelling ◽  
Predatory Fish ◽  
Reference Level ◽  
Recreational Fisheries ◽  
The Baltic Sea ◽  
Distribution Models ◽  
The Baltic

Abstract Improving water clarity is a core objective for eutrophication management in the Baltic Sea, but may influence fisheries via effects on fish habitat suitability. We apply an ensemble of species distribution models coupled with habitat productivity functions and willingness-to-pay estimates to assess these effects for two coastal predatory fish species, European perch (Perca fluviatilis) and pikeperch (Sander lucioperca). The models predicted a 37% increase in perch and 59% decrease in pikeperch biomass if reaching the reference level for water clarity in the Baltic Sea Action Plan. Reaching the target level was predicted to increase perch biomass by 13%. However, the associated economic gain for the recreational fisheries sector was countervailed by an 18% pikeperch reduction. Still, a net benefit was predicted since there are six times more fishing days for perch than pikeperch. We exemplify how ecological modelling can be combined with economic analyses to map and evaluate management alternatives.

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