Lee C G, Farrell A P, Lotto A, MacNutt M J, Hinch S G, Healey M C
Biological Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
J Exp Biol. 2003 Sep;206(Pt 18):3239-51. doi: 10.1242/jeb.00547.
Our knowledge of the swimming capabilities and metabolic rates of adult salmon, and particularly the influence of temperature on them, is extremely limited, and yet this information is critical to understanding the remarkable upstream migrations that these fish can make. To remedy this situation, we examined the effects of temperature on swimming performance and metabolic rates of 107 adult fish taken from three stocks of sockeye salmon Oncorhynchus nerka and one stock of coho salmon O. kisutch at various field and laboratory locations, using large, portable, swim tunnels. The salmon stocks were selected because of differences in their ambient water temperature (ranging from 5 degrees C to 20 degrees C) and the total distance of their in-river migrations (ranging from approximately 100 km for coastal stocks to approximately 1100 km for interior stocks). As anticipated, differences in routine metabolic rate observed among salmon stocks were largely explained by an exponential dependence on ambient water temperature. However, the relationship between water temperature and maximum oxygen consumption (MO2max), i.e. the MO2 measured at the critical swimming speed (Ucrit), revealed temperature optima for MO2max that were stock-specific. These temperature optima were very similar to the average ambient water temperatures for the natal stream of a given stock. Furthermore, at a comparable water temperature, the salmon stocks that experienced a long and energetically costly in-river migration were characterized by a higher MO2max, a higher scope for activity, a higher Ucrit and, in some cases, a higher cost of transport, relative to the coastal salmon stocks that experience a short in-river migration. We conclude that high-caliber respirometry can be performed in a field setting and that stock-specific differences in swimming performance of adult salmon may be important for understanding upstream migration energetics and abilities.
我们对成年鲑鱼游泳能力和代谢率的了解，尤其是温度对它们的影响，极其有限，然而这些信息对于理解这些鱼类能够进行的非凡溯河洄游至关重要。为了改善这种情况，我们使用大型便携式游泳隧道，在不同的野外和实验室地点，研究了温度对取自三种红大马哈鱼（Oncorhynchus nerka）种群和一种银大马哈鱼（O. kisutch）种群的107条成年鱼游泳性能和代谢率的影响。选择这些鲑鱼种群是因为它们的环境水温不同（范围从5摄氏度到20摄氏度）以及它们在河流中洄游的总距离不同（沿海种群约为100公里，内陆种群约为1100公里）。正如预期的那样，鲑鱼种群之间观察到的常规代谢率差异在很大程度上可以用对环境水温的指数依赖性来解释。然而，水温与最大耗氧量（MO2max）之间的关系，即在临界游泳速度（Ucrit）下测量的MO2，显示出MO2max的温度最适值是种群特异性的。这些温度最适值与特定种群的出生河流的平均环境水温非常相似。此外，在可比水温下，经历了漫长且耗能高的河流洄游的鲑鱼种群，相对于经历短河流洄游的沿海鲑鱼种群，其特征是具有更高的MO2max、更高的活动范围、更高的Ucrit，在某些情况下，还有更高的运输成本。我们得出结论，在野外环境中可以进行高精度的呼吸测量，并且成年鲑鱼游泳性能的种群特异性差异对于理解溯河洄游的能量学和能力可能很重要。
