The swimming physiology of the European eel under regulable hyperbaric conditions

在SPEER（欧洲鳗在可调节高压条件下的游泳生理）中，我们的目标是在分子（rnas测序，酶活性），组织（膀胱，性腺）和有机体（呼吸）水平上研究升高的静水压力对迁徙欧洲银鳗游泳生理和能量学的影响。此外，为了更好地确定成功产卵洄游的生理要求和阈值，将审查与寄生虫感染和污染物（多氯联苯、重金属）等因素的相互作用。我们希望量化和解开影响银鳗迁徙过程中各种因素的个体风险潜力：1)利用三个新型高压游泳隧道进行短期和长期游泳试验，评估压力下银鳗的游泳能力和代谢需求。到目前为止，之前的研究调查了鳗鱼在大气压下游泳的情况，在游泳隧道中，在加压室中，或者在非常小的水量和很短的调查时间内。然而，在SPEER中，我们将使用大水量（205升）的游泳水槽来模拟大型雌鳗在静水压力下长达一个月的初始产卵迁移。此外，我们将创建多氯联苯、重金属和鳔寄生虫的单独负荷方案，以获得预测潜在迁移失败的阈值。2)在分子和生化水平上评估升高（恒定和可变）静水压力对膀胱功能的影响。目前尚不清楚在产卵迁徙过程中所遇到的高静水压力如何影响膀胱的代谢活动和性能及其作为浮力器官的作用。在此背景下，我们还将重点关注有毒物质（多氯联苯，重金属）和寄生虫（A.crassus）对膀胱组织代谢活动和膀胱基本功能的影响。3)研究长时间高压游泳对性腺成熟的影响。雌性银鳗从激素注射中获利，但通常产生低质量的卵，可以通过游泳锻炼来优化，以产生高质量的配子和卵。通过将长期游泳运动与恒定或可变的静水压力相结合，我们将创造一个更现实的环境，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.