Population-Level Differences in Growth and Immunity in Response to Crude Oil Exposure in Threespine Stickleback

Crude oil causes many harmful effects in fish, including increased mortality, reduced growth, morphological abnormalities, and immunotoxicity. Despite the well-detailed effects that crude oil has on many fish, how threespine stickleback (Gasterosteus aculeatus) are impacted by crude oil, especially as juveniles, is not well known. Studies on early life stages are essential as oil is known to cause developmental abnormalities that significantly impact survival. Oil impacts on stickleback could have resounding impacts on the food chain. They are a ubiquitous sentinel species in the northern hemisphere and food source for many fish. Effects may not be the same across populations; however, as they exhibit intra- and inter-population genetic diversity and have freshwater, anadromous, and marine phenotypes. This study aimed to assess the population-level effects of crude oil exposure on juvenile threespine stickleback. The first experiment examined a single population, and the second compared four populations (one anadromous and three freshwater). In each experiment, fish were exposed to 10 ppm of Alaska North Slope crude oil at seven days post-fertilization and then depurated from 14-28 days post-fertilization. Oil exposure effects on growth and immunity were measured at 14 and 28 days post-fertilization. Population-level differences in growth and immunity were observed in response to exposure suggesting that the impacts of oil on a single population may not be translatable to other populations. Overall, stickleback were somewhat resilient to oil exposure, as mortality did not increase; however, oil exposure significantly impacted some populations, suggesting some populations may be less tolerant of oil exposure