A comprehensive understanding of how interactions between catchments and downstream lakes affect fish growth rate is lacking for many species and systems, yet is necessary for predicting impacts of environmental change on productivity of freshwater fish populations. We investigated among-lake variability in growth rate of Northern Pike (Esox lucius), a fish species of widespread subsistence and commercial importance. Northern Pike were captured from 11 subarctic lakes that span 60,000 km² and four ecoregions in the Dehcho Region of the Northwest Territories, Canada. Growth rates were related to stable isotope ratios and to lake and catchment physicochemistry. Growth, modelled using increment widths (n = 2953) measured on cleithra (n = 432), was significantly slower (p < 0.001, adj. r² = 0.78) in lakes subject to greater inferred catchment influence, which was quantified using a combination of lake and catchment characteristics. While Northern Pike growth rate was not related to δ¹⁵N, it was positively related to δ¹³C (p < 0.001, adj. r² = 0.75). Further analyses revealed that benthic invertebrates in lakes subject to greater inferred catchment influence had more depleted δ¹³C ratios, and we posit that Northern Pike growth is slower in these lakes because terrestrially derived organic matter has relatively lower nutritional value and bioaccessibility, but further research is necessary. By linking current among-lake variability in Northern Pike growth to trophic ecology and to both lake and catchment physicochemical data, results inform predictions of how future changes to subarctic lakes and catchments may affect fish growth and productivity.

许多物种和系统缺乏对集水区和下游湖泊之间的相互作用如何影响鱼类生长速度的全面了解，但对于预测环境变化对淡水鱼类种群生产力的影响是必要的。我们调查了北梭鱼( Esox lucius )生长速率的湖间变异性，这是一种具有广泛生存和商业重要性的鱼类。Northern Pike 是从加拿大西北地区 Dehcho 地区跨越 60,000 公里^{2 的}11 个亚北极湖泊和四个生态区捕获的。增长率与稳定同位素比率以及湖泊和集水区的物理化学有关。生长，使用增量宽度 ( n  = 2953)建模，在 cleithra ( n = 432）， 在受更大推断集水区影响的湖泊中明显更慢（p  < 0.001，调整r ² = 0.78），这是使用湖泊和集水区特征的组合进行量化的。虽然北梭鱼生长率与 δ ¹⁵ N无关，但与 δ ¹³ C呈正相关（p  < 0.001，调整后r ²  = 0.75）。进一步的分析表明，受推断集水区影响较大的湖泊中的底栖无脊椎动物具有更多的 δ ¹³消耗C 比率，我们假设北梭鱼在这些湖泊中的生长速度较慢，因为陆源有机质的营养价值和生物可及性相对较低，但需要进一步研究。通过将北梭鱼生长的当前湖间变异与营养生态以及湖泊和集水区的物理化学数据联系起来，结果可以预测亚北极湖泊和集水区的未来变化可能如何影响鱼类生长和生产力。