Abstract：
Disproportional changes (i.e. allometry) in shark morphology relative to increasing body size have been attributed to shifts in function associated with niche shifts in life history, such as in habitat and diet. Photographs of blue sharks (Prionace glauca, 26-145 kg) were used to analyze changes in parameters of body and fin morphology with increasing mass that are fundamental to swimming and feeding. We hypothesized that blue sharks would demonstrate proportional changes (i.e. isometry) in morphology with increasing mass because they do not undergo profound changes in prey and habitat type; accordingly, due to geometric scaling laws, we predicted that blue sharks would grow into bodies with greater turning inertias and smaller frontal and surface areas, in addition to smaller spans and areas of the fins relative to mass, which are parameters that are associated with the swimming performance in sharks. Many aspects of morphology increased with isometry. However, blue sharks demonstrated negative allometry in body density, whereas surface area, volume and roll inertia of the body, area, span and aspect ratio of both dorsal fins, span and aspect ratio of the ventral caudal fin, and span, length and area of the mouth increased with positive allometry. The dataset was divided in half based on mass to form two groups: smaller and larger sharks. Besides area of both dorsal fins, relative to mass, larger sharks had bodies with significantly greater turning inertia and smaller frontal and surface areas, in addition to fins with smaller spans and areas, compared to smaller sharks. In conclusion, isometric scaling does not necessarily imply functional similarity, and allometric scaling may sometimes be critical in maintaining, rather than shifting, function relative to mass in animals that swim through the water column.
摘要：
鲨鱼形态相对于体型增加的不成比例变化（即异速变化）归因于与生活史中的生态位变化相关的功能变化。比如栖息地和饮食。蓝鲨鱼的照片(Prionaceglauca，26-145kg）用于分析身体和鳍形态参数随质量增加的变化，这是游泳和进食的基础。我们假设，随着质量的增加，蓝鲨的形态会呈现成比例的变化（即等距），因为它们不会在猎物和栖息地类型上发生深刻的变化；因此，由于几何尺度定律，我们预测，蓝鲨将长成具有更大的转向惯性和更小的额叶和表面积的身体，除了鳍的跨度和面积相对于质量较小之外，它们是与鲨鱼游泳性能相关的参数。形态学的许多方面随着等轴测量而增加。然而,蓝鲨鱼的身体密度显示为负异速变化，而表面积，身体的体积和滚动惯性，area,两个背鳍的跨度和纵横比，腹侧尾鳍的跨度和纵横比，和跨度，口腔的长度和面积随正异速变化而增加。数据集根据质量分为两半，形成两组：更小和更大的鲨鱼。除了两个背鳍的面积，相对于质量，较大的鲨鱼的身体具有更大的旋转惯性和更小的正面和表面区域，除了具有较小跨度和面积的鳍，与小鲨鱼相比。总之,等距缩放不一定意味着功能相似性，异速缩放有时可能对维持至关重要，而不是转移，相对于游过水柱的动物的质量。
