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The role of temperature and salinity on Paracentrotus lividus aquaculture: determination of threshold values for cultivation
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Abstract(s)
O ouriƧo-do-mar pĆŗrpura europeu Paracentrotus lividus (Lamarck, 1816) Ć© uma espĆ©cie abundante nas costas rochosas de Portugal. As colheitas regulares de ouriƧo-do-mar para a indĆŗstria alimentar aumentaram consideravelmente em Portugal nos Ćŗltimos anos, devido ao elevado valor econĆ³mico das suas ovas, o que sem regulamentaĆ§Ć£o apropriada pode levar a uma sobrexploraĆ§Ć£o das populaƧƵes naturais. A definiĆ§Ć£o de um plano de gestĆ£o sustentĆ”vel requer conhecimentos de base acerca da resposta da populaĆ§Ć£o a diferentes condiƧƵes ambientais, o que Ć© particularmente importante no contexto das alteraƧƵes climĆ”ticas, uma vez que o aumento das temperaturas pode afetar o metabolismo dos organismos ectotĆ©rmicos. Por outro lado, o desenvolvimento de sistemas de produĆ§Ć£o em aquacultura eficientes para a produĆ§Ć£o de P. lividus poderĆ” contribuir para uma diminuiĆ§Ć£o da pressĆ£o sobre os stocks naturais.
Neste estudo, foi avaliado o desempenho de adultos de ouriƧo-do-mar europeu, considerando o Ćndice de atividade, mortalidade, crescimento, concentraĆ§Ć£o de proteĆnas e atividade de GST (Glutathione-S-transferase), em seis salinidades constantes (de 10 a 35) num primeiro ensaio experimental, e, num segundo ensaio, em seis temperaturas constantes (de 18ĀŗC a 28ĀŗC). Para alcanƧar os objetivos, foram feitas observaƧƵes regulares durante o ensaio (12h) ao longo de 168h para o ensaio da salinidade e de 204h para o ensaio da temperatura e, no final, avaliados parĆ¢metros biomĆ©tricos, concentraĆ§Ć£o de proteĆnas e do biomarcador de stress oxidativo (atividade de GST).
No ensaio de salinidade observou-se que os tratamentos com salinidade mais baixa (10, 15 e 20) apresentaram valores mais baixos do Ćndice de atividade e valores de mortalidade mais elevados do que nos tratamentos com salinidade mais elevada (25, 30 e 35). Os valores de Lt50 obtidos para a salinidade 10 e 20 foram de 139.42 e 146.13 horas de exposiĆ§Ć£o contĆnua e para a salinidade 15 de 134.60 horas. Os valores de concentraĆ§Ć£o de proteĆnas foram mais elevados nos organismos nos tratamentos de salinidade 25 e 30, semelhante ao registado nos organismos colhidos no campo.
Em relaĆ§Ć£o ao teste de temperatura, os maiores valores do Ćndice de atividade foram registados nos tratamentos a 22ĀŗC e 24ĀŗC, e ao longo do teste houve tambĆ©m respostas diferentes em relaĆ§Ć£o aos tempos de observaĆ§Ć£o. Neste caso, os tratamentos que apresentaram mortalidade mais elevada foram os de 26Āŗ e 28ĀŗC, havendo, no entanto, mortalidade em todos os tratamentos no final do ensaio. Os valores Lt foram calculados para as temperaturas de 26ĀŗC e 28ĀŗC em que o valor Lt50 foi de 161.73 e 166.84 horas de exposiĆ§Ć£o, respetivamente. O tratamento que apresentou o valor mais elevado de concentraĆ§Ć£o de proteĆnas foi a temperatura de 22ĀŗC, que foi maior do que o valor encontrado nos organismos recolhidos no campo. O registo da atividade do GST foi mais elevado nas temperaturas de 18ĀŗC e 20ĀŗC, o valor obtido para os organismos recolhidos no campo foi semelhante ao encontrado nos organismos no tratamento da temperatura de 22ĀŗC.
De uma forma geral, P. lividus responde melhor a salinidades mais elevadas, sofrendo maior impacto de salinidades baixas, a apresenta uma melhor performance a 22ĀŗC, sofrendo impactos significativos a temperaturas mais elevadas (> 26ĀŗC).
The European purple sea urchin Paracentrotus lividus (Lamarck, 1816) is an abundant species on the rocky coasts of Portugal. The regular harvesting of sea urchins for the food industry has increased considerably in Portugal in recent years, due to the high economic value of their roe, which without appropriate regulation may lead to a depletion of natural populations. The definition of a sustainable management plan requires basic knowledge about the response of the population to different environmental conditions, which is particularly important in the context of climate change, since rising temperatures can affect the metabolism of ectothermic organisms. On the other hand, the development of efficient aquaculture production systems could contribute to a decrease in the pressure on natural stocks. In this study, the performance of the adults european sea urchin was investigated, assessing activity index, mortality, growth, protein concentration, and GST activity under six distinct salinity treatments (10 to 35), in a first experimental assay, and under six temperature treatments (18ĀŗC to 28ĀŗC), in a second assay. To achieve our objectives, observations were made every 12 h, over 168h for the salinity assay and 204h for the temperature assay and at the end of the assays biometric parameters, protein concentration and oxidative stress biomarker (GST activity) were evaluated. In the salinity test it was observed that the treatments with lower salinity (10, 15 and 20) showed lower values of the activity index and higher mortality values than the treatments with higher salinity (25, 30 and 35). The Lt50 values obtained for salinity 10 and 20 were 139.42 and 146.13 hours of continuous exposure and for salinity 15 the 134.60 hours. Protein concentration values were higher in organisms in salinity treatments 25 and 30, similar to that recorded in organisms collected in the field. Regarding the temperature test, the highest values of the activity index were recorded in the treatments at 22ĀŗC and 24ĀŗC, and throughout the test there were also different responses regarding observation times. In this case, the treatments that presented the highest mortality were those at 26ĀŗC and 28ĀŗC. However, there was mortality in all treatments at the end of the test. Lt values were calculated for the temperatures of 26ĀŗC and 28ĀŗC where Lt50 value was 161.73 and 166.84 hours of exposure, respectively. The treatment that presented the highest value of protein concentration was the temperature of 22ĀŗC, which was higher than the value found in the organisms collected in the field. The record of GST activity was higher in the temperatures of 18ĀŗC and 20ĀŗC, the value obtained for the organisms collected in the field was similar to that found in the organisms in the 22ĀŗC temperature treatment. In general, P. lividus responds better to higher salinities, suffering greater impact at low salinities, and performs better at 22ĀŗC, suffering significant impact at higher temperatures (> 26ĀŗC).
The European purple sea urchin Paracentrotus lividus (Lamarck, 1816) is an abundant species on the rocky coasts of Portugal. The regular harvesting of sea urchins for the food industry has increased considerably in Portugal in recent years, due to the high economic value of their roe, which without appropriate regulation may lead to a depletion of natural populations. The definition of a sustainable management plan requires basic knowledge about the response of the population to different environmental conditions, which is particularly important in the context of climate change, since rising temperatures can affect the metabolism of ectothermic organisms. On the other hand, the development of efficient aquaculture production systems could contribute to a decrease in the pressure on natural stocks. In this study, the performance of the adults european sea urchin was investigated, assessing activity index, mortality, growth, protein concentration, and GST activity under six distinct salinity treatments (10 to 35), in a first experimental assay, and under six temperature treatments (18ĀŗC to 28ĀŗC), in a second assay. To achieve our objectives, observations were made every 12 h, over 168h for the salinity assay and 204h for the temperature assay and at the end of the assays biometric parameters, protein concentration and oxidative stress biomarker (GST activity) were evaluated. In the salinity test it was observed that the treatments with lower salinity (10, 15 and 20) showed lower values of the activity index and higher mortality values than the treatments with higher salinity (25, 30 and 35). The Lt50 values obtained for salinity 10 and 20 were 139.42 and 146.13 hours of continuous exposure and for salinity 15 the 134.60 hours. Protein concentration values were higher in organisms in salinity treatments 25 and 30, similar to that recorded in organisms collected in the field. Regarding the temperature test, the highest values of the activity index were recorded in the treatments at 22ĀŗC and 24ĀŗC, and throughout the test there were also different responses regarding observation times. In this case, the treatments that presented the highest mortality were those at 26ĀŗC and 28ĀŗC. However, there was mortality in all treatments at the end of the test. Lt values were calculated for the temperatures of 26ĀŗC and 28ĀŗC where Lt50 value was 161.73 and 166.84 hours of exposure, respectively. The treatment that presented the highest value of protein concentration was the temperature of 22ĀŗC, which was higher than the value found in the organisms collected in the field. The record of GST activity was higher in the temperatures of 18ĀŗC and 20ĀŗC, the value obtained for the organisms collected in the field was similar to that found in the organisms in the 22ĀŗC temperature treatment. In general, P. lividus responds better to higher salinities, suffering greater impact at low salinities, and performs better at 22ĀŗC, suffering significant impact at higher temperatures (> 26ĀŗC).
Description
Keywords
P. lividus Aquacultura Temperatura Salinidade Ćndice de atividade Tempo letal Paracentrotus lividus Aquaculture Temperature Salinity Lethal time