Abstract:
Ocean warming will continue to affect the growth, body condition and geographic distributions of marine fishes and understanding these effects is an urgent challenge for fisheries research and management. Determining how temperature is recorded in fish otolith carbonate, provides an additional chronological tool to investigate thermal histories, preferences and patterns of movement throughout an individual\'s life history. The influence of three water temperature treatments (22°C, 25°C, and 28°C) on hatchery-reared juvenile stout whiting, Sillago robusta, was tested using a controlled outdoor mesocosm system. Fish were measured for change in length and weight, and body condition was determined using bioelectrical impedance analysis. Sagittal otoliths were analysed for stable oxygen (δ18Ootolith) and carbon (δ13Cotolith) isotopes via isotope ratio mass spectrometry. Whiting kept at 22°C were significantly smaller and had diminished body condition compared to fish in 25°C and 28°C, which did not significantly differ from each other. The δ18O otolith values of stout whiting demonstrated a negative temperature-dependent fractionation relationship which was similar in slope but had a different intercept to the relationships reported for inorganic aragonite and other marine fish species. The δ13C otolith values also showed a negative relationship with water temperature, and the calculated proportion of metabolic carbon M in otoliths differed between fish reared in the coolest (22°C) and warmest (28°C) temperature treatments. Overall, the results suggest that stout whiting may have reached an upper growth threshold between 25°C and 28°C, and that growth and body condition may be optimised during warmer seasons and toward the northerly regions of their distribution. Otolith oxygen thermometry shows promise as a natural tracer of thermal life history, and species-specific fractionation equations should be utilised when possible to prevent errors in temperature reconstructions of wild-caught fish.
摘要:
海洋变暖将继续影响生长,海洋鱼类的身体状况和地理分布以及了解这些影响是渔业研究和管理的紧迫挑战。确定如何记录鱼耳石碳酸盐中的温度,提供了一个额外的按时间顺序排列的工具来调查热历史,个人生活史中的偏好和运动模式。三种水温处理的影响(22°C,25°C,和28°C)在孵化场饲养的幼年粗壮的白色上,西拉戈·罗布斯塔,使用受控的户外中观系统进行了测试。测量鱼的长度和重量的变化,并使用生物电阻抗分析确定身体状况。通过同位素比质谱法分析矢状耳石的稳定氧(δ18Ootolith)和碳(δ13Cotolith)同位素。与25°C和28°C的鱼类相比,在22°C下保持的白色鱼明显较小,并且身体状况有所下降,彼此之间没有显着差异。粗壮白垩的δ18O耳石值显示出负的温度依赖性分馏关系,其斜率相似,但截距与无机文石和其他海洋鱼类报道的关系不同。δ13C耳石值也与水温呈负相关,在最冷(22°C)和最热(28°C)温度处理下饲养的鱼之间,耳石中代谢碳M的计算比例有所不同。总的来说,结果表明,粗壮白鲸可能已经达到25°C至28°C之间的生长上限阈值,在温暖的季节和分布的偏北地区,生长和身体状况可能会得到优化。耳石氧气测温显示出有望成为热生命史的自然示踪剂,在可能的情况下,应使用特定物种的分馏方程,以防止野生捕获鱼的温度重建错误。