17:15 〜 19:15
[BBG01-P04] Relationship between size and weight of a Japanese precious coral skeleton, Corallium japonicum
キーワード：宝石サンゴ、アカサンゴ、骨格
Japanese precious coral is highly valued internationally, however, there are concerns about a decrease in the number of individuals due to overfishing and poaching. To achieve the conservation of resources and species, basic information on populations is required, but information on Japanese coral that lives in relatively deep water at depths of 80 m or more is limited. This study aimed to clarify the relationship between the morphological characteristics of the skeletons of a Japanese precious coral, Corallium japonicum, and their weight.
We used a total of 137 coral skeletons that were exhibited at the 2019 official auction. This measurement was conducted with the cooperation of the NGO The Precious Coral Protection and Development Association. Three size parameters: the height from the base (height), the width in the direction perpendicular to the height (width), the diameter of the base (diameter), were measured using sample photographs taken with a scale by Image J, and compared the weight measured on site.
As a result of comparing each size parameter and weight, all size parameters showed a positive correlation with weight, but the best correlation was with width. In the Mediterranean coral, Corallium rubrum, which inhabits shallower waters than Japanese corals and for which basic research on populations has progressed, it has been reported that the diameter and weight showed the best correlation, while there is no significant correlation between height and weight (Ref 1, 2). In this study, the diameter of the base was likely underestimated compared to previous studies because the fragments were collected by dredging, but these differences may reflect differences in species and habitat. The results of this study could provide basic information for accurately estimating the weight of precious corals observed in ROV surveys and for formulating effective resource protection measures.
Reference
[1] Rossi et al. (2008) Marine Biology, 154:533-545.
[2] Priori et al. (2013) Estuarine, Coastal and Shelf Science, 118: 43-49.
We used a total of 137 coral skeletons that were exhibited at the 2019 official auction. This measurement was conducted with the cooperation of the NGO The Precious Coral Protection and Development Association. Three size parameters: the height from the base (height), the width in the direction perpendicular to the height (width), the diameter of the base (diameter), were measured using sample photographs taken with a scale by Image J, and compared the weight measured on site.
As a result of comparing each size parameter and weight, all size parameters showed a positive correlation with weight, but the best correlation was with width. In the Mediterranean coral, Corallium rubrum, which inhabits shallower waters than Japanese corals and for which basic research on populations has progressed, it has been reported that the diameter and weight showed the best correlation, while there is no significant correlation between height and weight (Ref 1, 2). In this study, the diameter of the base was likely underestimated compared to previous studies because the fragments were collected by dredging, but these differences may reflect differences in species and habitat. The results of this study could provide basic information for accurately estimating the weight of precious corals observed in ROV surveys and for formulating effective resource protection measures.
Reference
[1] Rossi et al. (2008) Marine Biology, 154:533-545.
[2] Priori et al. (2013) Estuarine, Coastal and Shelf Science, 118: 43-49.