Abstract There is increased commercial interest in the production of lumpfish (Cyclopterus lumpus) as a biological control against sea lice infections in Atlantic salmon farming. To ensure a sustainable supply of lumpfish, reliable captive reproduction is required however, optimal husbandry and conditions for captive broodstock performance remain unknown. Artificial fertilisation of gametes remains the preferred management strategy for lumpfish, but this requires an effective milt management protocol. The present study tested several milt extender solutions for short term cold storage and validated sperm concentration assessment of lumpfish milt. Results demonstrated lumpfish sperm has a long motility survival time (motile for up to 3 h) when compared to other marine teleosts. Importantly, all extenders used in the study were non-activating on dilution of the milt. Lumpfish milt was successfully stored at 4 °C in Modified Turbot Extender (MTE), Herring Ringers Solution and Aquaboost SpermCoat (Cryogenetics, Norway) for up to 14 days post stripping. MTE performed more effectively with regards to maintenance of sperm activation time in comparison to the other tested extenders. There was a significant positive correlation between sperm concentration identified through cell counts using a haemocytometer and both packed cell volume (spermatocrit) and measured optical density at 640 nm (r2 = 97.42 ± 2.14). This suggests both packed cell volume and spectrophotometric measurements can be effective methods for rapidly assessing sperm concentration in lumpfish. This study validated several options for quantifying sperm concentration and short-term cold storage of lumpfish milt that can be used for hatchery management in lumpfish aquaculture.

中文翻译：

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鲽鱼（Cyclopteruslumpus.L）Milt的短期冷藏和精子浓度评估

摘要 在大西洋鲑鱼养殖中，生产鲳鱼（Cyclopteruslumpus）作为一种生物防治海虱感染的方法引起了越来越多的商业兴趣。为了确保块鱼的可持续供应，需要可靠的圈养繁殖，然而，圈养亲体性能的最佳饲养和条件仍然未知。配子的人工受精仍然是块鱼的首选管理策略，但这需要有效的鱼米管理协议。本研究测试了几种用于短期冷藏的鱼精补充剂解决方案，并验证了鲱鱼鱼精的精子浓度评估。结果表明，与其他海洋硬骨鱼相比，鲽鱼精子具有较长的运动存活时间（运动时间长达 3 小时）。重要的，研究中使用的所有增量剂在稀释精液时均未激活。在 4 °C 下成功地将鱼鲱鱼精储存在改良的 Turbot Extender (MTE)、Herring Ringers 溶液和 Aquaboost SpermCoat（Cryogenetics，挪威）中，在剥离后长达 14 天。与其他测试的延长剂相比，MTE 在维持精子激活时间方面表现得更有效。使用血细胞计数器通过细胞计数确定的精子浓度与压实细胞体积（精子比容）和 640 nm 处测量的光密度之间存在显着的正相关（r2 = 97.42 ± 2.14）。这表明压实细胞体积和分光光度法测量都可以成为快速评估肿块鱼精子浓度的有效方法。