Environmental influences on fish cardiovascular function and control

鱼类具有真正的全球分布，生活在温度范围从-1.8到42摄氏度的沃茨中，可以含有很少或没有氧气（即，是缺氧的），并且盐含量可能显著变化（例如，河口）。此外，人类活动（包括气候变化的加速）给这些鱼类带来了更大的压力，在某些地区，这导致了物种的迁移或灭绝。如果鱼类要在这些环境变量的短期和长期变化中生存，促进向组织输送氧气的生理调整（例如，心脏泵送更多的血液，血液血红蛋白水平的增加，通气的调整，血流的重新分配）至关重要。事实上，已经有人提出，随着温度的升高，心脏功能的限制是鱼类耐热性的主要决定因素。拟议的研究将提供重要的见解：1）什么因素（2）鱼类的免疫系统、应激生理和心血管功能之间的相互作用; 3）为什么在长期低氧适应后心脏功能受损;以及4）有多少血液流向卵巢（卵子），它是否可以被控制，以及它如何受到温度，水氧水平和盐度变化的影响。后一项研究很重要，因为在不同的环境条件下，维持向卵输送氧气和营养物质可能对确保产生大量有活力的后代至关重要，从而确保鱼类种群的健康。

Fish have a truly global distribution and live in waters where temperatures range from -1.8 to 42oC, that can contain little to no oxygen (i.e., are hypoxic), and may vary dramatically in salt content (e.g., estuaries). Further, human activities (including accelerated climate change) are placing added pressures on these fish, and in some areas this has lead to the displacement or extinction of species. Physiological adjustments that promote an increase in oxygen delivery to the tissues (e.g. more blood pumped by the heart, an increase in blood haemoglobin levels, adjustments in ventilation, the redistribution of blood flow) are critical if fish are to survive short- and long-term variations in these environmental variables. Indeed, it has been suggested that limitations in cardiac function as temperatures increase are a primary determinant of a fish's thermal tolerance. The proposed research will provide important insights into: 1) what factors (mechanisms) limit heart function in fishes at high temperatures; 2) interactions between the fish's immune system, stress physiology and cardiovascular function; 3) why heart function is compromised following acclimation to prolonged hypoxia; and 4) how much blood flows to the ovaries (eggs), whether it can be controlled, and how it is impacted by changes in temperature, water oxygen levels and salinity. The latter studies are important because the maintenance of oxygen and nutrient delivery to the eggs under varied environmental conditions is likely vital to ensuring that a large number of viable offspring are produced, and thus, the health of fish populations.