The swimming physiology of the European eel under regulable hyperbaric conditions

在SPEER（The swimming physiology of the European eel under regulable hyperbaric conditions）中，我们旨在从分子（RNA测序、酶活性）、组织（鱼鳔、性腺）和有机体（呼吸）水平上研究静水压力升高对欧洲银鳗迁移的游泳生理和能量学的影响。此外，寄生虫感染和污染物（多氯联苯，重金属）等因素的相互作用将进行检查，以更好地确定生理要求和阈值成功产卵迁移。我们希望通过以下方式量化和理清影响银鳗迁移的各种因素的个体风险潜力：1） 利用三个新颖的高压游泳隧道进行短期至长期的游泳试验，以评估银鳗在压力下的游泳能力和代谢需求。到目前为止，以前的研究已经调查了鳗鱼在游泳隧道中的大气压下游泳，在加压室中游泳，或者在很小的水量和很短的调查时间内游泳。然而，在SPEER中，我们将使用具有较大水量（205 l）的游泳水槽来模拟静水压力下大雌性鳗鱼的初始产卵迁移，时间长达一个月。此外，我们还将创建多氯联苯、重金属和鱼鳔寄生虫的单独负载方案，以获得预测潜在迁移失败的阈值。（二） 在分子和生物化学水平上评估静水压力升高（恒定和可变）对鱼鳔功能的影响。目前尚不清楚在产卵迁移过程中遇到的静水压力升高如何影响代谢活动和鱼鳔的性能及其作为浮力器官的作用。在这种情况下，我们也将集中有毒物质（多氯联苯，重金属）和寄生虫（A.crassus）对鳔组织的代谢活动和鳔的基本功能的影响。第三章 探讨长时间加压游泳对性腺成熟的影响。雌性银鳗从激素注射中获益，但通常产生低质量的卵子，这些卵子可以通过游泳运动来优化，以产生高质量的配子和卵子。通过将长期的游泳运动与恒定或可变的静水压力相结合，我们将创造一个更真实的环境，有助于产生高质量的配子，并加速欧洲鳗鱼的生命周期关闭。

In SPEER (The swimming physiology of the European eel under regulable hyperbaric conditions) we aim at investigating the effect of elevated hydrostatic pressure on the swimming physiology and energetics of migrating European silver eel at molecular (RNAsequencing, enzyme activities), tissue (swimbladder, gonads) and organismal (respiration) levels. Moreover, the interaction with factors such as parasitic infestation and pollutants (PCBs, heavy metals) will be examined in order to better define physiological requirements and thresholds for a successful spawning migration. We want to quantify and disentangle the individual risk potentials of the various factors affecting silver eels during their migration by:1) Performing short- to long-term swimming trials using three novel hyperbaric swimming tunnels to assess the swimming capacity and metabolic requirements of silver eels under pressure. So far, previous studies have investigated swimming in eels either at atmospheric pressure in swim tunnels, in pressurized chambers or, when combined, in very small water volumes and with short investigation periods. In SPEER, however, we will use swimming flumes with a large water volume (205 l) to simulate the initial spawning migration of large female eels under hydrostatic pressure for time periods up to a month. Additionally, we will create individual load schemes of PCBs, heavy metals and swimbladder parasites, to gain threshold values for projecting potential migration failure. 2) Assessing the effect of elevated (constant and variable) hydrostatic pressure on the functioning of the swimbladder at the molecular and biochemical level. It is currently unknown how the elevated hydrostatic pressure encountered during the spawning migration affects metabolic activity and performance of the swimbladder and its role as buoyancy organ. In this context we will also focus of the effect of toxicants (PCBs, heavy metals) and parasites (A.crassus) on metabolic activity of swimbladder tissue and the fundamental functioning of the swimbladder. 3) Investigating the effect of prolonged swimming under pressure on gonadal maturation. Female silver eels profit from hormone injections but often produce low quality eggs, which could be optimized by swimming exercise to create high quality gametes and eggs. By combining long-term swimming exercise with constant or variable hydrostatic pressure, we will create a more realistic environment that could help produce high quality gametes and accelerate the life-cycle closure of the European eel.