Increasing biological knowledge for a better management of the Eastern Baltic Sea cod

Stock assessment is the synthesis of information on life history, fishery monitoring, and resource surveys. It is a critical management tool for monitoring the abundance of commercial fish populations, as well as for predicting the consequences of policy decisions. However, without the key biological reference parameters, e.g., growth rate and age, the estimation of spawning stock biomass and fishing mortality rate is unpredictable. During the past two decades, a number of changes in biology and ecological conditions has affected the Eastern Baltic cod stock, raising concerns among fisheries scientists and managers. Deteriorated quality of key biological parameters for stock assessment, such as true age, growth rates, and reproductive traits, in combination with changes in environmental and ecological conditions, has led the failure of the analytical stock assessment in 2014, leaving the present stock status unclear. Currently, it is unknown whether the drop in mean size and the disappearance of large individuals is due to a decrease in growth rates or by increased natural mortality. Therefore, whether the stock has suffered a decrease in productivity or an increase in mortality (fishing pressure or other natural causes) is an open dilemma, with large implication for fisheries management.  During my PhD, I will make use of results from historical tagging experiments, as well as new international tagging program to provide the necessary information on growth and mortality of Eastern Baltic cod to aid solving the issues with stock assessment. In addition, I will investigate the effects of the changes in growth and condition on cod reproductive potential. Finally, I will try to integrate all the gained biological knowledge (growth, mortality and reproductive potential) in new assessment models for a better management of the Baltic Sea cod

Analytical performance evaluation of the new GEM® Premier™ 5000 analyzer in comparison to the GEM® Premier™ 4000 and the RapidPoint® 405 systems

Abstract Aim of the study Blood gas analysis (BGA) is essential for the diagnosis and management of acid-base imbalances. We evaluated and compared the analytical characteristics of the new GEM® Premier™ 5000 (GP5000) (Instrumentation Laboratory, Bedford, MA, United States) BGA point-of-care (POC) device with those of the GEM® Premier™ 4000 (GP4000) (Instrumentation Laboratory, Bedford, MA, United States) and RapidPoint® 405 (RP405) (Siemens Healthcare, Milan, Italy) POC analyzers. The effect of sample mixing on patient results was also studied. Material and methods Quantitative measurement of pH, pCO2, pO2, Na+, K+, Cl−, iCa2+, glucose, lactate, tHb, COHb, MetHb, O2Hb, HHb and Hct were carried out. The imprecision study (IS) and method comparison study (MS) were performed according to CLSI EP guidelines, using respectively internal as well as external quality controls (IS) and whole blood samples collected from the routine analysis (MS). Results GP5000 demonstrated satisfactory characteristics in the IS showing comparable (GM4000) or even better (RP405) imprecision results than the routine POC devices. Good performance was observed in the MS both using GP4000 and RP405 as reference instruments. Pre-analytical sample management can heavily affect the accuracy of BGA results. In the specimen mixing evaluation, a significant improvement in results accuracy was observed when mixing procedures were more meticulous. Conclusions Considering the overall analytical performance observed, the ease of use of the system, the rapid time-to-results and the innovative Intelligent Quality Management technology (iQM2®), GP5000 seems suitable to be used in clinical care for safe patient management. Additionally, effective sample mixing upon draw and before analysis is strongly advisable in order to ensure the most clinically reliable BGA results

Perfil de un grupo de hipertensos: aspectos biosociales, conocimientos y adhesión al tratamiento

OBJECTIVE: To characterize a group of hypertensive patients in relation to beliefs, knowledge, attitudes and factors that could affect treatment compliance. METHODS: The data were collected by interviewing hypertensive outpatients. RESULTS: A total of 511 hypertensive patients were studied: most were women, white, with elementary education, and 53±11 years old. The patients had high levels of knowledge about hypertension and treatments. However, they interrupted the treatment due to the expensive medicines and the lack of instructions. Furthermore, they believed they had to take medicines only when they felt unwell, and they did not attend their medical appointment usually due to forgetfulness and personal problems. Regarding the attitudes against the antihypertensive treatment, hypertensive patients forgot to take the medicines, took the medication at different hours, stopped taking the medication on their own account, did not follow instructions, and did not exercise regularly. CONCLUSION: The profile of the hypertensive patients identified aspects that can hamper treatment compliance.OBJETIVO: Caracterizar um grupo de hipertensos em relação a crenças, conhecimentos, atitudes e fatores que podem interferir na adesão ao tratamento. MÉTODOS: Os dados foram coletados através de entrevista com hipertensos em seguimento ambulatorial. RESULTADOS: Foram estudados 511 hipertensos: a maioria mulheres, brancas, com escolaridade de nível fundamental, 53,0 ±11,0 anos. Foram verificados índices elevados de conhecimento sobre a doença e tratamento. Porém, o tratamento foi interrompido devido a remédios muito caros e falta de orientação e acreditavam que devem tomar os medicamentos somente quando se sentem mal, além de faltarem à consulta médica, principalmente por esquecimento e problemas particulares. Em relação às atitudes frente ao tratamento, observou-se que esquecem de tomar os remédios, não tomam no mesmo horário, deixam de tomar por conta própria, não seguem as orientações e não praticam exercícios físicos regularmente. CONCLUSÃO: A caracterização dos hipertensos identificou aspectos que podem dificultar a adesão ao tratamento.OBJETIVO: Caracterizar a un grupo de hipertensos en relación a las creencias, conocimientos, actitudes y factores que pueden interferir en la adhesión al tratamiento. MÉTODOS: Los datos fueron recolectados a través de una entrevista a hipertensos con seguimiento en consulta externa. RESULTADOS: Participaron 511 hipertensos: la mayoría mujeres, blancas, con un nivel de escolaridad primario y edad de 53,0 ±11,0 años. Fueron verificados índices elevados de conocimiento sobre la enfermedad y el tratamiento. Sin embargo, el tratamiento fue interrumpido debido a medicamentos muy caros y falta de orientación, considerando que deben tomar los medicamentos solamente cuando se sienten mal, además se identificó falta a la consulta médica, principalmente por olvido y problemas particulares. En relación a las actitudes frente al tratamiento, se observó que olvidan de tomar los remedios, no lo hacen en el mismo horario, dejan de tomar por cuenta propia, no siguen las orientaciones y no practican ejercicios físicos regularmente. CONCLUSIÓN: la caracterización de los hipertensos permitió identificar aspectos que pueden dificultar la adhesión al tratamiento

Stock connectivity patterns and indications of sub-stock component structuring of cod in the Sound in the western Baltic Sea

Sustainable management of fish stocks requires knowledge of stock structure and connectivity between spawning and feeding habitats. Cod in the Sound in the western Baltic Sea are an example of a stock component with complex connectivity patterns. Currently cod in this area are managed as part of the western Baltic cod stock, while several studies suggest potential connectivity with the neighbouring stock in Kattegat. Here we assess the degree of ecological connectivity of cod in the Sound with the neighbouring areas using historical tagging data from 1957 to 1987, and contemporary growth data from trawl surveys collected between 2007 and 2021. Furthermore, data from cod tagged outside of the Sound between 1960 and 2018 and recaptured in the Sound was used to examine immigration from outside areas. The ecological connectivity between the Sound and Kattegat appeared to be considerable, primarily during the spawning season. Furthermore, cod tagged in the northern Sound were most likely to be recaptured in Kattegat while cod tagged in the southern part of the Sound were mainly recaptured in the Sound. Only 40 out of 16,789 tagged cod released outside of the Sound were eventually recaptured inside the Sound. Overall, these results highlight the need for further examination into the current stock structure of cod in the western Baltic and adjacent areas

Increasing the biological knowledge of Baltic Sea cod: growth, movements and reproductive potential from historical and contemporary data

Knowledge about life-history traits of commercially exploited fish stocks and their possible changes over time is essential for implementing a sustainable management. Biological parameters such as growth rate, fecundity and movement patterns are in fact, underlying determinants for stock responses to environmental forcing and fishing exploitation. Historically, the Eastern Baltic cod (EBC) has been one of the most important commercial stocks in the Baltic Sea but currently is one of the most severely threatened fish stocks in Europe. During the past two decades, a number of changes in biology and ecological conditions has affected the EBC stock, raising concerns among fisheries scientists and managers. One of the main biological changes has been the contraction in the size structure of the stock towards smaller fish. However, due to the large uncertainties in age estimations, it was unclear whether this change was the result of reduced growth or increased mortality of older individuals, or a combination of both. This has led to the failure of the analytical stock assessment between 2014 and 2018. The contracted size distribution of the stock could have important implications also for its potential fecundity, affecting recruitment, and movement patters. The aim of this thesis was to increase the knowledge on key biological parameters of EBC, including growth, fecundity and movement patterns. To this end, I collated data from historical and contemporary tagging experiments, to estimate EBC individual growth using length-based methods. The results revealed that the current growth of cod is the lowest observed in the past 7 decades indicating very low productivity. These estimations have contributed to the re-establishment of the EBC analytical stock assessment since 2019. In addition, the thesis showed that the currently low growth that lead to smaller fish sizes, together with the observed decline in condition, is expected to negatively affect the fecundity and thus the reproductive output of the stock. The re-analyses of historical data confirmed the presence of different movement behaviours, stationary and migratory, with larger distances covered by cod released in the northern and central Baltic areas compared to cod released in the southern Baltic. In addition, larger fish seemed to move over larger distances than smaller fish, underlying the importance of having larger fish with higher potential of dispersion in the stock. Furthermore, data from the recent tagging experiment indicate enduring resident strategy in the southern Baltic area. This thesis presents methods and results that increased the understanding of the EBC biology, relevant for its management and that could be applied for future monitoring

Into the wild: coupling otolith and archival tag records to test assumptions underpinning otolith chemistry applications in wild fish

Chronological records of elemental concentrations in fish otoliths are a widely used tool to infer the environmental conditions experienced by individual fish. To interpret elemental signals within the otolith, it is important to understand how both external and internal factors impact ion uptake, transport and incorporation. In this study, we have combined chronological records from otoliths and archival data storage tags to quantify the influence of internal (sex, size, age, growth) and external (temperature, depth, salinity) conditions on otolith elemental chemistry of cod (Gadus morhua) in natural settings of the Baltic Sea. This study focused on elements primarily under physiological control: Phosphorus (P), magnesium (Mg) and zinc (Zn); and elements under environmental control: Strontium (Sr), barium (Ba) and manganese (Mn). Based on known spatial and temporal patterns in environmental conditions and fish size, growth, and maturity, we posed a series of hypotheses of expected otolith element patterns. Partial effects of internal and external drivers on element concentration were analyzed using a Linear Mixed Model approach with random variables (fish and year). Predicted effects of otolith concentrations of all elements under physiological control (P, Mg, Zn) showed similar trends, with distinct seasonal patterns (lowest concentration in late spring, highest concentrations in winter), and a positive correlation with water temperature, in addition to higher Zn and lower P in spawning individuals. Predicted effects of otolith concentrations of elements expected to be predominantly under environmental control showed the predicted geographic and depth-related trends based on ambient salinity (Ba) and coastal hypoxia (Mn). However, contrary to expectation, Sr was unrelated to salinity. Predicted otolith Ba, Sr and Mn concentrations also exhibited pronounced seasonal patterns that were out of phase with each other but appeared to be partly explained by spawning/feeding migrations. While performing laboratory validation studies for adult fish is typically not possible, these results highlight the importance of assessing local water chemistry and freshwater endmembers in one's study system before otolith elemental chemistry can be reliably used to reconstruct fish habitat use and environmental histories

Endocrine-Disrupting Compounds: Measurement in Tampa Bay, Removal from Sewage and Development of an Estrogen Receptor Model

The significance of endocrine-disrupting compounds (EDCs) in the environment has only recently come to the forefront of scientific research, policy debates, water utilities management and public awareness. EDCs have the ability to interfere with the normal functioning of the endocrine system of humans and other animals. Numerous chemicals are included in the class of compounds known as EDCs, and exposure is widespread. These compounds are found in a variety of environmental matrices (e.g., marine and freshwater systems, sediment, soil), transported there primarily through sewage effluent discharge and recycling of sewage sludge for topical fertilizer use. This transport to the environment serves as the primary route of exposure for aquatic and terrestrial organisms living there. Furthermore, these compounds are also found in consumer products, food and drinking water--which serve as the exposure source for human beings. Multiple examples of endocrine disruption have been documented in humans and animals, and certain EDCs have been implicated in each case. The future of public and environmental health will depend upon mitigating the effects of these chemicals. This purpose of this dissertation is to provide an initial understanding of EDC occurrence in the Tampa Bay region of south Florida, and to complement the existing body of EDC research with regards to marine systems. It focuses on estrogenic EDCs, specific compounds which target the estrogen axis of the endocrine system. Six estrogenic EDCs were chosen based on their documented prevalence in the environment, prevalence in sewage, and for their suspected endocrine-disrupting effects: estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, bisphenol-A and nonylphenol. These compounds were verified to be amenable to and detectable by gas chromatography-mass spectrometry analysis. Since the occurrence of EDCs in aquatic environments of the Tampa Bay region had not been previously characterized, the initial phase of the research focused on quantification of the six estrogenic EDCs in Tampa Bay area water, sediment, and sewage influent and effluent. All targeted EDCs were present in 89% of sewage samples, while 100% of the samples contained at least one or more EDCs. The concentrations of EDCs in marine aqueous and sediment samples tended to decrease with increasing distance from the wastewater treatment plant discharge site. The ubiquitous presence of these estrogenic EDCs in the Tampa Bay area is cause for concern with respect to endocrine disruption in local terrestrial and aquatic wildlife. Since the Tampa Bay region is home to a wide variety of marine organisms, constant exposure to EDCs could result in ecosystem-level effects, as these compounds can impair reproductive fitness and lead to other adverse health effects. This research also served to enlarge the existing scientific literature on EDC occurrence, as many marine and freshwater systems continue to be characterized globally. The very basis for expecting to find EDCs in the Tampa Bay area had come from the fact that the main source of environmental contamination is typically the effluent discharge from area wastewater treatment plants. Conventional wastewater treatment plant processes are designed to reduce the amount of organic matter, pathogens and nutrients from the incoming influent. However, the processes are not as effective in removing micropollutants, including EDCs. These compounds notoriously evade traditional wastewater treatment technologies and are found even in tertiary-treated effluent. For this reason, the second phase of the research assessed an electro-chemical technique for the removal of the same six EDCs. The removal technique was tested on a laboratory scale and has a commercial-sized counterpart which can be integrated at the level of the wastewater treatment plant. In order to test the removal efficiency, samples of influent and tertiary-treated effluent were spiked with the six EDCs. The mean concentration of each EDC component was statistically lower after treatment (removal range = 42% - 98.2%), demonstrating the effectiveness of this electro-chemical process for EDC removal from both raw and treated sewage. The significance of the results lies in the fact that if this method is implemented, then future wastewater treatment plant effluent discharge (similar to that of the Tampa Bay region) could be less impacted by EDCs and therefore cleaner for the environment into which it is being discharged. For the final phase of the research, the use of computational techniques to simulate human endogenous estrogen binding to its receptor was started as a foundation for future models to eventually predict endocrine-disrupting potential of different chemical compounds. We built an estradiol-human estrogen receptor model, and used molecular dynamic simulations to determine the binding free energy. The calculated total binding free energy of estradiol bound to the ligand binding domain of the human estrogen receptor was found to be -16.85 kcal/mol, which is in range of the experimental value of -12.40 kcal/mol. Humans are chronically exposed to low doses of EDCs every day, which makes endocrine disruption a considerable public health issue. Human exposure to EDCs is completely different from marine organism exposure, but the adverse effects are no less significant. The successful completion of this model serves as a platform for 1. Testing the human model against endocrine-disrupting compounds, 2. Subsequent models that will be developed for different species, including marine species important to Tampa Bay. Substantial data exist regarding the exposures and health risks associated with EDCs in humans and wildlife on a global scale. As the pressing issues of climate change and carbon emissions are at the top of the list of environmental concerns, it is important to note that mitigating the effects of EDCs should not be overlooked and will be an important responsibility of regulatory agencies in the near future