Tubbataha Reefs Natural Park: the first comprehensive elasmobranch assessment reveals global hotspot for reef sharks: Fishes Checklist

A total of 113 BRUV surveys were completed throughout 2015 and 2016. The BRUV surveys documented a CMaxN of 237 elasmobranchs from 14 species and one unidentified Carcharhinid. The overall CPUE from both years was 2.09 (Table 1), with at least one elasmobranch encounter occurring in 92.03% (n = 104) of surveys. Carcharhinus amblyrhynchos, the most abundant species, with a CMaxN of 103, occurred in 54.87% of surveys, recording an overall CPUE of 0.91 (x = 0.91 +- 1.64 SD). Triaenodon obesus were also abundant, with a CMaxN of 98, and were present in 71.68% of surveys with an overall CPUE of 0.87 (x = 0.87 +- 0.84 SD). Other shark species observed during two years of sampling were, in order of decreasing CMaxN, tiger shark Galeocerdo cuvier (CMaxN = 8), blacktip reef shark Carcharhinus melanopterus (8), scalloped hammerhead shark Sphyrna lewini (7), tawny nurse shark Nebrius ferrugineus (2), thresher shark Alopias sp. (2), silky shark Carcharhinus falciformis (1), silvertip shark Carcharhinus albimarginatus (1), and whale shark Rhincodon typus (1). Batoid species observed were spotted eagle ray Aetobatus spp. (2), round ribbontail ray Taeinurops meyeni (1), bluespotted ribbontail ray Taeniura lymma (1), and a manta ray Mobula sp. (1). There was no significant difference between years in CPUE of C. amblyrhynchos in shallow habitats (PERMANOVA, p = 0.297, Pseudo-F = 1.139) and deep habitats (p = 0.48, Pseudo-F = 0.607). Similarly, no significant difference in the abundance of T. obesus; abundance was evident between years in shallow (p = 0.19, Pseudo-F = 2.122) and deep habitats (p = 0.171, Pesudo-F 2.28).本研究于2015至2016年间共完成113次诱饵远程水下视频（Baited Remote Underwater Video, BRUV）采样。本次采样共记录14种板鳃类共计237尾个体的最大相对丰度（Count MaxN, CMaxN），另包含1种未鉴定的真鲨科物种。两年整体的单位捕捞努力量渔获量（Catch Per Unit Effort, CPUE）为2.09（详见表1），且92.03%的采样（n=104）至少观测到1尾板鳃类个体。灰礁鲨（Carcharhinus amblyrhynchos）为本次采样的优势物种，其CMaxN达103，出现在54.87%的采样站位中，整体CPUE为0.91（平均值±标准差：0.91±1.64）。白顶礁鲨（Triaenodon obesus）同样丰度较高，CMaxN为98，在71.68%的采样站位中被记录，整体CPUE为0.87（平均值±标准差：0.87±0.84）。按CMaxN降序排列，两年采样期间观测到的其他鲨鱼物种依次为：鼬鲨（Galeocerdo cuvier，CMaxN=8）、乌翅真鲨（Carcharhinus melanopterus，CMaxN=8）、路氏双髻鲨（Sphyrna lewini，CMaxN=7）、锈色护士鲨（Nebrius ferrugineus，CMaxN=2）、长尾鲨属未定种（Alopias sp.，CMaxN=2）、镰状真鲨（Carcharhinus falciformis，CMaxN=1）、白边真鲨（Carcharhinus albimarginatus，CMaxN=1）及鲸鲨（Rhincodon typus，CMaxN=1）。观测到的鳐类物种包括：花点鹰鳐属未定种（Aetobatus spp.，CMaxN=2）、迈氏条尾魟（Taeniurops meyeni，CMaxN=1）、蓝斑条尾魟（Taeniura lymma，CMaxN=1）及蝠鲼属未定种（Mobula sp.，CMaxN=1）。浅海生境中灰礁鲨的CPUE在两年间无显著差异（置换多元方差分析，Permutational Multivariate Analysis of Variance, PERMANOVA，p=0.297，伪F=1.139），深海生境亦未检测到显著差异（p=0.48，伪F=0.607）。类似地，白顶礁鲨的丰度在两年间亦无显著差异：浅海生境（p=0.19，伪F=2.122）及深海生境（p=0.171，伪F=2.28）均未出现显著变化。