ABSTRACT: As feed-additive aquaculture expands to open ocean areas, there is concern that ecologically important habitats may be adversely impacted by sedimentation of farm wastes. In this study, we investigated assimilation of salmon faecal wastes by an ecosystem engineering bivalve that occurs in open ocean environments (Atrina zelandica), as well as effects on physiology and fatty acid metabolism. A. zelandica were subjected to one of 3 treatment diets (fish faeces, 1:1 mix of algae:faeces and algae) in a 51 d laboratory trial. We found a diet-related response in fatty acid composition, including increased prevalence of oleic acid (OA) in digestive tissues of A. zelandica fed on both the fish faeces diet and the mixed diet, indicating fish wastes were assimilated in both treatments. Fish waste consumption was related to a more marked reduction in fatty acid content of digestive gland, as well as lower proportions of long-chain polyunsaturated fatty acids (LC-PUFA) in digestive tissues. Fatty acid composition in gonad and muscle tissues was more strongly influenced by sex. Regardless of dietary treatment, females accumulated C₁₈ fatty acids in gonad tissues, particularly OA, which may preclude the use of OA as a fish waste tracer in this organ. The accumulation of specific fatty acids according to sex may indicate a capacity for preferential selection and retention or biosynthesis of biologically important fatty acids. If present, these mechanisms may increase resilience of A. zelandica to stress from deficiencies in LC-PUFA when using fish wastes as a trophic subsidy.

中文翻译：

---

生态系统工程双壳类 Atrina zelandica 对养鱼场废物的同化

摘要：随着饲料添加剂水产养殖扩展到公海区域，人们担心具有重要生态意义的栖息地可能会因农场废物的沉积而受到不利影响。在这项研究中，我们研究了开放海洋环境中的生态系统工程双壳类动物（Atrina zelandica）对鲑鱼粪便废物的同化，以及对生理和脂肪酸代谢的影响。在一项为期 51 天的实验室试验中， A. zelandica接受了 3 种治疗饮食中的一种（鱼粪便、藻类：粪便和藻类 1:1 的混合物）。我们发现脂肪酸组成存在与饮食相关的反应，包括以鱼粪便饮食和混合饮食喂养的泽兰鱼消化组织中油酸（OA）的患病率增加，表明鱼的废物在两种处理中都被同化了。鱼类废物的消耗与消化腺脂肪酸含量更显着减少以及消化组织中长链多不饱和脂肪酸（LC-PUFA）比例降低有关。性腺和肌肉组织中的脂肪酸组成受性别的影响更大。无论饮食治疗如何，雌性都会在性腺组织中积累 C ₁₈脂肪酸，特别是 OA，这可能会妨碍使用 OA 作为该器官中的鱼类废物示踪剂。根据性别的特定脂肪酸的积累可能表明优先选择和保留或生物合成生物学上重要的脂肪酸的能力。如果存在，这些机制可能会提高泽兰鱼在使用鱼类废物作为营养补贴时对缺乏 LC-PUFA 造成的压力的恢复能力。