Ontogenetic shifts in morphology and resource use of cisco Coregonus artedi.
Ontogenetic shifts in morphology and resource use of cisco Coregonus artedi.
复制标题
cisco Coregonus artedi 形态和资源利用的个体发生变化。
作者：
A. Muir;P. Vecsei;T. Pratt;C. Krueger;M. Power;J. Reist
先前描述的两种来自加拿大北部大奴湖的湖泊cisco Coregonus spp. morphs[即小（<300 mm叉长，L(F)），低鳃耙（≤44）形态和大（≥300 mm L(F)），高鳃耙（≥45）形态]被发现与cisco Coregonus artedi同义。两种体型之间的几何形状没有差异，也不能通过24种尺寸校正的线性测量来区分，这表明两组具有相似的表型。几何质心大小（鱼体长、质量和年龄的复合变量）与所有线性性状均呈显著正相关，表明鱼体形态随年龄的增长而变化。刺鱼总数量（N(GR)）随L(F)的增大而增大，N(GR) = 36.3 + 0.034L(F)。刺鱼的数量和表型随年龄和大小的变化可以用生境和营养资源利用的变化来解释。在0- 30m、30- 60m、60- 90m和bb0 - 90m深度的地层中，不同大小类别的相对丰度不同，这表明随着鱼类年龄的增长，它们的栖息地发生了变化。大型artidi的δ(13)C较低，δ(15)N略高，表明其对远洋猎物资源（即更多或更大的浮游动物，如Mysis spp.）的依赖程度高于小型artidi，而小型artidi对底栖猎物的依赖程度略高。鳃棘形状和数量一直是冠状碱分类中的关键诊断特征；根据这里提出的发现，个体发生的变化应该在分类中考虑。
Two previously described lacustrine cisco Coregonus spp. morphs [i.e. a small (<300 mm fork length, L(F)), low-gillraker (≤44) morph and a large (≥300 mm L(F) ), high-gillraker (≥45) morph] from Great Slave Lake, NT, Canada, were found to be synonymous with cisco Coregonus artedi. Geometric body shape did not differ between the two size classes nor could they be differentiated by 24 size-corrected linear measurements, indicating that the two groups had similar phenotypes. Strong, positive correlations between all linear characters and geometric centroid size (a composite variable of fish body length, mass and age) suggested that body morphology changed with age as fish grew. Total gillraker number (N(GR)) increased with L(F) according to: N(GR) = 36.3 + 0.034L(F). Differences in gillraker number and phenotype with age and size were explained by shifts in habitat and trophic resource use. Relative abundance within 0-30, 30-60, 60-90 and >90 m depth strata differed between size classes suggesting that morphology changed when fish shifted their habitat as they grew older. Large C. artedi had lower δ(13)C and slightly higher δ(15)N, indicating greater reliance on pelagic prey resources (i.e. more or larger zooplankton, such as Mysis spp.), compared to small C. artedi, which relied slightly more on benthic prey. Gillraker shape and number have always been used as key diagnostic characters in coregonine taxonomy; based on the findings presented here, ontogenetic shifts should be accounted for in resulting classifications.