School of Natural Sciences (Chemistry), University of Tasmania, Locked Bag 1371, Launceston, 7250, Tasmania, Australia.
School of Natural Sciences (Chemistry), University of Tasmania, Locked Bag 1371, Launceston, 7250, Tasmania, Australia.
Environ Pollut. 2022 Jan 1;292(Pt A):118360. doi: 10.1016/j.envpol.2021.118360. Epub 2021 Oct 13.
Muscle melanisation in sand flathead is visible as black spots in the normally white flesh of fish. It is widespread in Tasmania, including at the Tamar Estuary, with increasing frequency of reporting by recreational fishers. The phenomenon is more prevalent in areas impacted by heavy metal pollution and has been linked to heavy metal accumulation. In this study, image processing software ImageJ was employed to study the phenomenon and to establish an objective rating system. A longitudinal profile plot was used to study the greying of the fillet. The degree of melanisation was rated based on the percentage surface area melanised on the surface and in transverse sections of fillets. A muscle melanisation scoring system for sand flathead was established based on visual interpretation using the macroscopic melanisation scoring criteria: melanisation scores 0 = <0.5%, 1 = 0.5-5%, 2 = 5-20%, and 3 = >20% (% = melanised surface area in proportion to the whole fillet). A refined image analysis technique was developed to quantify the percentage of melanised muscle surface area and the muscle melanisation scoring system was statistically validated. Sand flathead fillet with higher melanisation score was shown to be linked to increased intensity of greyness and greater numbers and size of black spots on the surface of fillets and within the flesh. The greying and black spots were primarily concentrated at the anterior region of fillet and around the dorsal vertebrae zone on transverse section of fillets. Overall, findings from this study established the use of image analysis techniques to validate visual inspection and to give a standardised and objective method to determine the degree of melanisation in sand flathead. As muscle melanisation appears to be linked to heavy metal pollution, the standardised scoring system would facilitate future research for environmental pollution and monitoring purposes.
肌肉黑色素沉着在沙平鲷的正常白色鱼肉中表现为黑色斑点。它在塔斯马尼亚广泛存在，包括塔马尔河口，越来越多的休闲渔民报告了这种现象。这种现象在受重金属污染影响的地区更为普遍，并且与重金属积累有关。在这项研究中，使用图像处理软件 ImageJ 来研究这一现象并建立一个客观的评分系统。使用纵向轮廓图来研究鱼片的变灰程度。根据鱼片表面和横截面上黑色素化的表面积百分比来对黑色素沉着程度进行评分。根据宏观黑色素沉着评分标准，建立了沙平鲷的肌肉黑色素沉着评分系统：黑色素沉着评分 0 = <0.5%，1 = 0.5-5%，2 = 5-20%，3 = >20%（% = 黑色素化表面面积与整个鱼片的比例）。开发了一种改进的图像分析技术来量化黑色素化肌肉表面面积的百分比，并对肌肉黑色素沉着评分系统进行了统计学验证。黑色素沉着评分较高的沙平鲷鱼片与表面和鱼肉内灰度增加、黑斑数量和大小增加有关。灰色和黑斑主要集中在鱼片的前部和横截面上的背椎区周围。总的来说，这项研究的结果确立了使用图像分析技术来验证肉眼观察，并为确定沙平鲷的黑色素沉着程度提供了一种标准化和客观的方法。由于肌肉黑色素沉着似乎与重金属污染有关，标准化评分系统将有助于未来进行环境污染和监测研究。
