VanderWright Wade J, Bigman Jennifer S, Elcombe Cayley F, Dulvy Nicholas K
Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada.
Conserv Physiol. 2020 Dec 4;8(1):coaa102. doi: 10.1093/conphys/coaa102. eCollection 2020.
Metabolically important traits, such as gill surface area and metabolic rate, underpin life histories, population dynamics and extinction risk, as they govern the availability of energy for growth, survival and reproduction. Estimating both gill surface area and metabolic rate can be challenging, especially when working with large-bodied, threatened species. Ideally, these traits, and respiratory physiology in general, could be inferred from external morphology using a faster, non-lethal method. Gill slit height is quick to measure on live organisms and is anatomically connected to the gill arch. Here, we relate gill slit height and gill surface area for five Carcharhiniform sharks. We compared both total and parabranchial gill surface area to mean and individual gill slit height in physical specimens. We also compared empirical measurements of relative gill slit height (i.e. in proportion to total length) to those estimated from field guide illustrations to examine the potential of using anatomical drawings to measure gill slit height. We find strong positive relationships between gill slit height and gill surface area at two scales: (i) for total gill surface area and mean gill slit height across species and (ii) for parabranchial gill surface area and individual gill slit height within and across species. We also find that gill slit height is a consistent proportion of the fork length of physical specimens. Consequently, relative gill slit height measured from field guide illustrations proved to be surprisingly comparable to those measured from physical specimens. While the generality of our findings needs to be evaluated across a wider range of taxonomy and ecological lifestyles, they offer the opportunity that we might only need to go to the library and measure field guide illustrations to yield a non-lethal, first-order approximation of the respiratory physiology of sharks.
代谢重要特征，如鳃表面积和代谢率，支撑着生物的生活史、种群动态和灭绝风险，因为它们决定了用于生长、生存和繁殖的能量供应。估算鳃表面积和代谢率可能具有挑战性，尤其是在研究大型濒危物种时。理想情况下，这些特征以及一般的呼吸生理学特征，可以通过一种更快、非致命的方法从外部形态推断出来。鳃裂高度在活体生物上易于测量，并且在解剖学上与鳃弓相连。在这里，我们研究了五种真鲨科鲨鱼的鳃裂高度和鳃表面积之间的关系。我们在物理标本中将总鳃表面积和鳃小片表面积与平均鳃裂高度和个体鳃裂高度进行了比较。我们还将相对鳃裂高度的实测值（即与全长的比例）与从野外指南插图估计的值进行了比较，以检验使用解剖图测量鳃裂高度的潜力。我们发现在两个尺度上鳃裂高度与鳃表面积之间存在很强的正相关关系：（i）跨物种的总鳃表面积与平均鳃裂高度之间，以及（ii）物种内和物种间的鳃小片表面积与个体鳃裂高度之间。我们还发现鳃裂高度在物理标本的叉长中所占比例是一致的。因此，从野外指南插图测量的相对鳃裂高度被证明与从物理标本测量的高度惊人地可比。虽然我们的研究结果的普遍性需要在更广泛的分类学和生态生活方式中进行评估，但它们提供了一个机会，即我们可能只需要去图书馆测量野外指南插图，就能得出鲨鱼呼吸生理学的非致命一阶近似值。
