| 1. |
- Kotta, Jonne, et al.
(author)
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Assessing the potential for sea-based macroalgae cultivation and its application for nutrient removal in the Baltic Sea
- 2022
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 839
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Journal article (peer-reviewed)abstract
- Marine eutrophication is a pervasive and growing threat to global sustainability. Macroalgal cultivation is a promising circular economy solution to achieve nutrient reduction and food security. However, the location of production hotspots is not well known. In this paper the production potential of macroalgae of high commercial value was predicted across the Baltic Sea region. In addition, the nutrient limitation within and adjacent to macroalgal farms was investigated to suggest optimal site-specific configuration of farms. The production potential of Saccharina latissima was largely driven by salinity and the highest production yields are expected in the westernmost Baltic Sea areas where salinity is >23. The direct and interactive effects of light availability, temperature, salinity and nutrient concentrations regulated the predicted changes in the production of Ulva intestinalis and Fucus vesiculosus. The western and southern Baltic Sea exhibited the highest farming potential for these species, with promising areas also in the eastern Baltic Sea. Macroalgal farming did not induce significant nutrient limitation. The expected spatial propagation of nutrient limitation caused by macroalgal farming was less than 100–250 m. Higher propagation distances were found in areas of low nutrient and low water exchange (e.g. offshore areas in the Baltic Proper) and smaller distances in areas of high nutrient and high water exchange (e.g. western Baltic Sea and Gulf of Riga). The generated maps provide the most sought-after input to support blue growth initiatives that foster the sustainable development of macroalgal cultivation and reduction of in situ nutrient loads in the Baltic Sea.
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| 2. |
- Holmgren, Noél, et al.
(author)
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A Concept of Bayesian Regulation in Fisheries Management
- 2014
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:11
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Journal article (peer-reviewed)abstract
- Stochastic variability of biological processes and uncertainty of stock properties compel fisheries managers to look for tools to improve control over the stock. Inspired by animals exploiting hidden prey, we have taken a biomimetic approach combining catch and effort in a concept of Bayesian regulation (BR). The BR provides a real-time Bayesian stock estimate, and can operate without separate stock assessment. We compared the performance of BR with catch-only regulation (CR), alternatively operating with N-target (the stock size giving maximum sustainable yield, MSY) and F-target (the fishing mortality giving MSY) on a stock model of Baltic Sea herring. N-targeted BR gave 3% higher yields than F-targeted BR and CR, and 7% higher yields than N-targeted CR. The BRs reduced coefficient of variance (CV) in fishing mortality compared to CR by 99.6% (from 25.2 to 0.1) when operated with F-target, and by about 80% (from 158.4 to 68.4/70.1 depending on how the prior is set) in stock size when operated with N-target. Even though F-targeted fishery reduced CV in pre-harvest stock size by 19–22%, it increased the dominant period length of population fluctuations from 20 to 60–80 years. In contrast, N-targeted BR made the periodic variation more similar to white noise. We discuss the conditions when BRs can be suitable tools to achieve sustainable yields while minimizing undesirable fluctuations in stock size or fishing effort.
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| 3. |
- Holmgren, Noél M. A., et al.
(author)
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MSY-orientated management of Baltic Sea herring (Clupea harengus) during different ecosystem regimes
- 2012
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In: ICES Journal of Marine Science. - : Oxford University Press. - 1054-3139 .- 1095-9289. ; 69:2, s. 257-266
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Journal article (peer-reviewed)abstract
- The Baltic Sea ecosystem has undergone dramatic changes, so-called ecosystem regime shifts, during the past four decades. Baltic Sea herring (Clupea harengus) spawning-stock biomass has declined to a third, and weight-at-age has halved as a result of food shortages and competition with sprat (Sprattus sprattus). The management objective for the herring stock is currently in transition from precautionary to maximum sustainable yield (MSY). The main basin Baltic Sea herring was modelled under the current ecosystem regime and the effect of a recovery of the cod (Gadus morhua) stock and the availability of planktonic food to levels found in the early 1980s analysed. A target of F-MSY = 0.16 for herring, which should decline to F-MSY = 0.10 with recovery of the cod stock, is proposed. An increase in the availability of planktonic food is estimated to more than double the yield at F-MSY = 0.27, overriding the negative effects of cod predation should there be a simultaneous increase in both cod and availability of planktonic food. The estimated net increase in yield is 40% at F-MSY = 0.20. Functions are presented to calculate FMSY and to estimate the expected yield depending on the abundance of cod and food availability. Retrospective application of the functions is indicative of overfishing of herring in the 1990s and early 2000s, and a net loss in yield, with a landing value of some E440 million.
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