Species point records from 1986 Bishop Scilly Isles Echinus population study

Echinus esculentus, normally the subject of a small scale commercial fishery in the Isles of Scilly during the winter months, was not collected during the winter of 1985/86. This report presents the results of the third survey of selected Echinus esculentus populations in the Isles of Scilly, which took place during September 1986. These are compared with data from the same sites obtained during September 1984 and 1985. Seven areas were sampled, four of which are classified as unfished and three as fished sites. Within each of the seven areas, sampling sites were located as closely as possible to those studied in the 1985 survey. The mean density of urchins ranges from 0.05/m2 to 0.49/m2. Within the precision of the methodology, these figures compare exactly to the range measured in 1985 (0.05/m2 to 0.40/m2). There is no significant difference in the density of urchins between fished and unfished sites. The mean diameter of E. esculentus ranged from 95 mm to 122 mm with an overall site mean of 105+2 mm (n = 12). This compares with a slightly lower and smaller range of 92 mm to 112 mm during 1985, but a similar overall site mean of 104+2 mm (n = 10). The mean diameter of urchins at unfished sites was smaller than that of fished sites (98+1, n = 4 and 107.6+2, n = 8 respectively), which was also true in both 1984 and 1985. No major physical changes have affected the sites since 1984, and the dominant fauna and flora appear to be unchanged. There is still no evidence of juvenile or young adult individuals (size <5 cm diameter) at the monitoring sites, although it is believed that juveniles are present at deeper sites which cannot be dived or remotely sampled within the remit of the present contract.

棘皮鱼（Echinus esculentus），通常为斯凯利恩群岛冬季小规模商业渔业的主题，但在1985/86年的冬季并未被采集。本报告展示了在1986年9月进行的斯凯利恩群岛选定棘皮鱼种群第三次调查的结果。这些数据与1984年9月和1985年同期同一地点获得的数据进行了比较。共对七个区域进行了采样，其中四个被划分为未捕捞区域，三个为捕捞区域。在每个七个区域中，采样点尽可能地位于1985年调查研究的点附近。海胆的平均密度介于0.05/m²至0.49/m²之间。在方法论的精度范围内，这些数据与1985年测量的范围（0.05/m²至0.40/m²）完全一致。在捕捞和未捕捞区域之间，海胆的密度没有显著差异。棘皮鱼的平均直径介于95毫米至122毫米之间，整体区域平均直径为105±2毫米（n = 12）。这与1985年的略低和更小的范围（92毫米至112毫米）相比，但整体区域平均直径相似，为104±2毫米（n = 10）。未捕捞区域海胆的平均直径小于捕捞区域（分别为98±1毫米，n = 4和107.6±2毫米，n = 8），这一点在1984年和1985年也都成立。自1984年以来，这些地点没有发生重大的物理变化，优势生物群落和植被似乎保持不变。监测站点至今仍未发现幼年或年轻成年个体（直径小于5厘米），尽管据信在更深的水域存在幼体，而这些水域超出了当前合同潜水或远程采样的范围。