Journal Articles
http://hdl.handle.net/1834/9431
2024-03-29T09:06:38ZModel uncertainty and simulated multispecies fisheries management advice in the Baltic Sea.
http://hdl.handle.net/1834/15431
Model uncertainty and simulated multispecies fisheries management advice in the Baltic Sea.
Bauer, Barbara; Horbowy, Jan; Rahikainen, Mika; Kulatska, Nataliia; Müller-Karulis, Barbel; Tomczak, Maciej T.; Bartolino, Valerio
Different ecosystem models often provide contrasting predictions (model uncertainty), which is perceived to be a major challenge impeding their use to support ecosystem-based fisheries management (EBFM). The focus of this manuscript is to examine the extent of model disagreements which could impact management advice for EBFM in the central Baltic Sea. We compare how much three models (EwE, Gadget and a multispecies stock production model) differ in 1) their estimates of fishing mortality rates (Fs) satisfying alternative hypothetical management scenario objectives and 2) the outcomes of those scenarios in terms of performance indicators (spawning stock biomasses, catches, profits). Uncertainty in future environmental conditions affecting fish was taken into account by considering two seal population growth scenarios and two nutrient load scenarios. Differences in the development of the stocks, yields and profits exist among the models but the general patterns are also sufficiently similar to appear promising in the context of strategic fishery advice. Thus, we suggest that disagreements among the ecosystem models will not impede their use for providing strategic advice on how to reach management objectives that go beyond the traditional maximum yield targets and for informing on the potential consequences of pursuing such objectives. This is especially true for scenarios aiming at exploiting forage fish sprat and herring, for which the agreement was the largest among our models. However, the quantitative response to altering fishing pressure differed among models. This was due to the diverse environmental covariates and the different number of trophic relationships and their functional forms considered in the models. This suggests that ecosystem models can be used to provide quantitative advice only after more targeted research is conducted to gain a deeper understanding into the relationship between trophic links and fish population dynamics in the Baltic Sea.
2019-01-01T00:00:00ZSize assessment in polychaete worms-application of morphometric correlations for common North Atlantic taxa.
http://hdl.handle.net/1834/15430
Size assessment in polychaete worms-application of morphometric correlations for common North Atlantic taxa.
Górska, Barbara; Gromisz, Sławomira; Włodarska-Kowalczuk, Maria
Body size is a basic animal feature that defines its functioning in multispecies assemblages. Polychaetes arenumerically dominant components of marine macrobenthos, playing a key role in benthic productivity. Theyare also the most problematic group regarding body-size assessments due to common fragmentation of fragilebodies during sample processing that inhibits direct assessments of their size and biomass. Here, we presentquantified relationships that allow an estimation of the total-body length based on morphometric features(widths of thoracic chaetigers) that remain intact after standard macrobenthic sample treatment. The best-fittedregression equations (p< 0.001,rfrom 0.41 to 0.99) were selected for 28 polychaete families, six orders, twoinfraclasses, and one subclass based on the measurements on 3580 complete individuals collected in the NorthAtlantic (Norwegian and Spitsbergen fjords and continental margin). In Capitellidae, Cirratulidae, Oweniidae,and Trichobranchidae, the shapes of the relationships differed among dominant species/genera, and so, specificformula was proposed. The method has been applied to assess the size spectra of macrozoobenthos based on18 van Veen grab samples collected at six stations in two Spitsbergen fjords. The percentage contribution ofcomplete individuals in polychaete biomass and abundance in size classes varied between 0% and 43%, withthe lowest percentages noted in two dominant families—Cirratulidae and Lumbrineridae. The presentedmethod is likely to be widely applied in studies requiring polychaete individual size assessments (e.g., benthicbiomass size spectra, population dynamics, and secondary production).
2019-01-01T00:00:00ZPolycyclic aromatic hydrocarbon contamination of Polish smoked fish: Assessment of dietary exposure.
http://hdl.handle.net/1834/15429
Polycyclic aromatic hydrocarbon contamination of Polish smoked fish: Assessment of dietary exposure.
Malesa-Ciećwierz, Małgorzata; Szulecka, Olga; Adamczyk, Maria
The aim of the study was to determine if the smoked fish being produced in Poland complies with the new, stricter limits set for BaP and PAH4. The effect of sample position in the smoking chamber was also studied. The margin of exposure (MoE) approach was used for assessing the risk of dietary exposure to PAHs from smoked fish products. The study material comprised of sprat, herring, mackerel, and salmon from a fish processing plant equipped with smoking chambers with external smoke generators. None of the smoked fish products studied exceeded the new, stricter limits set for BaP and PAH4. The MoE indicators far exceed the limit of 10,000 (values lower than this indicate a potential risk to consumer health). The sensory analysis identified significant differences among the products studied that indicate the high quality of cold‐smoked salmon fillets and the statistically significant lower quality of a smoked salmon abdominal parts.
2019-01-01T00:00:00ZFeeding by two closely related species of Chironomus (Diptera: Chironomidae) in south Baltic lagoons, with implications for competitive interactions and resource partitioning.
http://hdl.handle.net/1834/15391
Feeding by two closely related species of Chironomus (Diptera: Chironomidae) in south Baltic lagoons, with implications for competitive interactions and resource partitioning.
Kornijów, Ryszard; Markiyanova, Marina; Lange, Evgenia
Four major categories of food items were determined in the gut content of chironomid larvae collected in the Curonian and Vistula Lagoons in the spring–summer period of 2009–2011. These were detritus (range from 88 to 92% of the gut content, by volume), matter of plant (2–7%) and animal origin (0.2–0.5%), and mineral particles (3–7%). Plant matter comprised pine pollen, conidia of fungi, cyanobacteria, green algae and diatoms. Matter of animal origin consisted of remnants of oligochaetes and rotifers. Food content was more diverse in the larvae inhabiting the Curonian Lagoon. The size of mineral particles in gut contents was significantly higher in C. balatonicus, although the distance between the bases of the maxillas, as a predictor of the size of the particles being eaten, was larger in C. plumosus. The gut content analysis suggested lack of clear food selectivity which potentially may lead to interspecific competition for food. However, the strength of interaction can be substantially weakened by several factors: (1) exceptionally favourable food conditions for benthic chironomids in both highly eutrophic lagoons, (2) the ability to occupy areas differing in salinity, (3) different feeding behaviour and (4) the ability to swallow particles of different size spectra.
2019-01-01T00:00:00Z