The submission was prepared to accompany the publication Haberle, Hackenberger et al. "Effects of climate change on gilthead seabream aquaculture in the Mediterranean" in Aquaculture (https://doi.org/10.1016/j.aquaculture.2023.740052). The simulations source code is available through GitHub repository at: https://github.com/QuantEcoLab/SparusSim_Haberle_et_al_2023 The Zanodo archive contains GeoTIFF images underlying the figures in the publication, with the corresponding description in the Readme file.

Due to high anthropogenic pressures, science-based coastal management required to ensure the sustainable use of coastal areas highly depends on environmental indicators used for decision-making. In this paper, we argue for the inclusion of Vibrio spp. abundance as a supplemental indicator of water quality for science-based coastal management by examining the environmental and bacterial indicators at a fish farm and a control site in Mali Ston Bay in the Adriatic Sea. Unexpectedly, heterotrophic bacteria, enterococci and Vibrio spp. were more abundant in the cold season, while E. coli and total coliforms, following a more traditional pattern, were more abundant in the warm season. Each of the currently used indicators has a specific purpose: heterotrophic bacteria indicate the presence of both nonpathogenic and pathogenic bacteria, while enterococci are pathogenic bacteria indicating fecal pollution. Vibrio spp. abundance additionally represents a non-fecal bacteria that can cause vibriosis in humans and aquatic organisms. Since vibriosis is the leading cause of disease-related fish mortality in aquaculture, pathogenic Vibrio spp. have large health and economic implications. These implications, as well as the added interpretative value when compared to other bacterial indicators, make Vibrio spp. abundance a good candidate as a water quality indicator. Significant dependence of the abundance on depth further differentiates Vibrio spp. from other indicators, thus bolstering the candidacy - especially in aquaculture areas. Before inclusion of any Vibrio spp. indicators into legislature, further research is needed particularly into (i) abundance thresholds characterizing water quality, and (ii) identification of species whose abundance should be monitored for best estimate of the disease risks.

The microalgae of the genus Pseudochloris/Picochlorum are characterized by fast growth, and wide nutrient (type and concentration) and salinity tolerance, all contributing towards exploration of their use in high-density biomass production and wastewater bioremediation. In this study, removal of nitrogen and phosphorus nutrients from oil refinery wastewater was monitored during growth of the marine eukaryotic microalgae Pseudochloris wilhelmii, with emphasis on biochemical analyses of its biomass quality to evaluate suitability for biodiesel production. A series of growth experiments under various nutrient and light regimes were performed in a temperature range of 20-30°C to evaluate nutrient removal and biomass growth dependence on temperature. The highest removal rate of dissolved inorganic nitrogen reached under the given experimental conditions was 0.823 mmol/(gday) accompanied by the corresponding biomass productivity of 115.2 mg/(Lday). Depending on light and temperature, the final lipid concentration ranged 181.5 – 319.8 mg/L. Furthermore, increase in nutrient load decreased the maximum specific growth rate by 25%, and the maximum specific removal rate of the dissolved inorganic nitrogen by 19%, whereas the duration of bioremediation process was nearly doubled. In contrast, constant light exposure expedited the nitrogen removal, i.e. bioremediation process, by almost 40%, while supporting over three times higher biomass productivity and the highest maximum specific growth rate of 0.528 g/(gday). The conditions favoring the highest nitrogen removal and highest toxicity reduction in oil refinery wastewater are met at 24°C and 130 µmol phot/(m2s). The highest proportion of carbon-binding to the P. wilhelmii biomass was noticed under the same conditions, thus indicating them as the most favorable conditions for hydrocarbon removal as well as for CO2 sequestration. Pseudochloris wilhelmii therefore represents a promising candidate for oil refinery wastewater remediation and valuable biomass cogeneration on a large-scale.

Managing the disturbance of visitors due to crowding is an important management task in protected areas with high use levels. To achieve this, managers need to know how the use level affects the perceived disturbance due to crowding. Here we present a method to predict the level of disturbance as a function of use level measured by number of visitors. In contrast to the visual approach where subjects are asked to evaluate acceptability of use levels from manipulated images of scenery, our approach uses data gathered from actual experiences: actual (measured) use levels and concurrent on-site data on levels of disturbance experienced by visitors. Using the example of Nature Park Telašćica, we show how these data can be acquired with limited resources (a smart-phone and short, time-stamped questionnaires), and demonstrate the subsequent analysis and model fitting. The resulting model estimates the probability that a visitor experiencing a given use level will report certain level of disturbance. We suggest a way of using the probability density functions to define an inherent limit of acceptable disturbance (LAD) due to crowding; the LAD can also be set to a desired value by management. Regardless of the definition, LAD can be used to determine the maximum acceptable use level as dictated by crowding considerations. The method gives predictions consistent with previous literature and can be used even when data are collected at low use levels.

Frequency, severity, and geographic range of harmful blooms caused by a dinoflagellate Prorocentrum minimum have been increasing significantly over the past few decades. The ability to adapt nutrient quotas and carbon content to a wide range of environmental conditions is one of the key factors for the proliferation of P. minimum. Understanding the limits of stoichiometric variability in terms of nutrient quotas and carbon content would help explain the observed trends and assist in P. minimum growth model creation. This manuscript aggregates information from 15 studies to investigate variability in nutrient quotas and carbon content for a broad range of P. minimum isolates and clonal lines. Nitrogen quota, phosphorus quota, and carbon content in the studies varied between 11-107.5pgNcell-1, 1.45-17.58pgPcell-1, and 70-656.36pgCcell-1, respectively. Regression analysis was used to estimate average nitrogen and phosphorus quotas as functions of carbon, and to show that carbon content variability explains 55% of nitrogen and 23% of phosphorus quota variability. Confidence intervals for data (CID) found during the analysis were used to define maximal and minimal nutrient quotas as functions of carbon content. The ratios of the upper and lower CID ranges can, therefore, be used to estimate nutrient storage capacity as a function of carbon content. The new results and comparison with other species show that, at least for P. minimum, carbon-based quotas are more suitable for modelling than cell-based quotas. Finally, results indicate that environmental nutrient availability affects quotas more than light does: while quota variability due to light remains within 80% CID, nutrient variability covers the 95% CID.

The decomposition of the organic matter, in the form of excess feed and excreted faeces, introduced to the environment by aquaculture can endanger living organisms by lowering oxygen levels. To increase the accuracy of the oxygen utilization assessment, we developed linear (L-MOD) and non-linear models (NL-MOD) for the dynamics of decomposition and accumulation of the organic matter, oxygen utilization and ammonium production. The models are based on mass-balance stoichiometric reactions for conversion of organic matter into bacterial biomass under aerobic conditions. Organic matter is represented by a general chemical formula sensitive to protein, carbohydrate and lipid content. The mass of organic matter is expressed in chemical oxygen demand (COD) units, providing more convenient tracking of oxygen utilization. Degradable part of the organic matter is distinguished from a non-degradable part. The model results are compared with the data sets from simulated aquaculture pond experiment.

With intent to help fisherman catch the most fish in the long run and to protect fish populations from extinction, major world fisheries regulation agencies have passed recommendations to implement sustainability in fisheries through the application of “maximum sustainable yield” (MSY). We show that application of MSY policy will lead to extinction of a large number of fish species in most ecosystems. More precisely, we show: approaching MSY in ecosystems means that most likely fish species will be driven to extinction in every fishery that includes exploitation of at least one trophic level which is directly or indirectly used as food for a higher trophic level. Because such single and multispecies fisheries make up a great majority of existing fisheries, attempts to reach MSY should be discouraged instead of being legally prescribed as a goal. Based on our result, we offer a simple prescription for managing a fishery in agreement with the Convention on Biological Diversity.

The Commission of the European Communities passed a resolution in 2006 to implement sustainability in EU fisheries through application of the maximum sustainable yield (MSY) based policy. It is shown here that attempts to reach MSY will lead towards extinction of species for every fishery that includes fishing of at least one trophic level which is directly or indirectly used as food for a higher trophic level. Because this condition is met by most single and multispecies fisheries, attempts to reach MSY should be discouraged instead of being legally prescribed as a goal. Based upon above result advice is given on how to manage a fishery which will not drive species to extinction.

A sediment trap validation study was conducted near the commercial sea bass and sea bream fish farm in order to assess the predictive capability of a particle tracking deposition model. The validation procedure consisted of two distinct phases. First, the deposition of particulate waste (i.e. fecal pellets and excess feed) was measured near a single net pen containing 19 tons of sea bass. Afterwards, the model quality was determined by statistical comparison of predicted and observed values.Goodness of fit analysis indicates that the model successfully accounts for more than 75% of variance in the observed deposition. At 5% significance level, predictions do not underestimate or overestimate observations and there is no bias. Mean absolute relative error of +/- 48.9% compares favorably to other published deposition models. Obtained results affirm the reliability of particle tracking techniques in modeling the aquaculture-derived benthic organic enrichment. (C) 2009 Elsevier B.V. All rights reserved.

Based on Santojanni et al. [Santojanni, A., Arneri, E., Barry, C., Belardinelli, A., Cingolani, N., Giannetti, G., Kirkwood, G., 2003. Trends of anchovy (Engraulis encrasicolus, L.) biomass in the northern and central Adriatic Sea. Sci. Mar. 67(3), 327–340] stock size estimates for the period from 1975 to 1996, we constructed a model to investigate population dynamics of anchovies. Using numeric simulations we calculate the maximum sustainable catch (MSC) as well as the optimum level of spawning stock to maintain the MSC. By comparing computed levels with Santojanni et al. estimates, we find that the anchovy population is below the optimum level, i.e. overfished since 1982. We find evidence of overfishing in 1982, 1985, 1986 and 1988. We claim the large catch in 1985 was more responsible for the collapse of anchovy fisheries in 1987 than low recruitment levels. We investigate possible ways of fishing using the two stage model by considering three fishing scenarios: the whole stock is fished with equal effort, only mature individuals are fished, mature and immature individuals are fished with unequal effort. We show that the best strategy is to fish only the spawning stock.