Anguilla luzonensis Watanabe, Aoyama & Tsukamoto 2009

An anguillid eel with variegated color marking with broad maxillary bands of teeth that is classified into the first group of Anguilla. Predorsal-fin length 28.6-33.1% of TL; preanal length 39.6-44.8% of TL; preanal length without head length (trunk length) 26.4-31.3% of TL; distance between the verticals through the anus and origin of the dorsal fin 9.3-13.9% of TL; LG 35.5-46.9% of HL; TV 103-107; and AV 40-42.The body is elongate. Body color when fresh was mottled with yellow, olive green, and dark brown or black, but it changed after formalin fixation, with the coloration being more dark or obscured. HL 10.8-15.1% of TL, predorsal lengths without head length 15.5-19.7% of TL. Distance from perpendicular through eye-center on the margin of upper jaw to angle of gape 29.9-41.8% of LG. Caudal vertebrae 61-66. (Ref. 83381).

Catadromous. Migrating from freshwater to the sea to spawn, e.g., European eels. Subdivision of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.

Vertebrae: 103 - 106

分布於西太平洋。主要在菲律賓呂宋島附近，臺灣及中國也有紀錄。

本種在台灣主要是混生於鰻苗洄游群當中。水產試驗所淡水繁養殖研究中心曾於2009年12月至2011年7月間，利用DNA萃取及序列的比對技術檢驗分別採自宜蘭、苗栗及彰化等地7梯次共405尾的黑鰻鰻線，測定出鱸鰻371尾(佔91.7%)、短鰭鰻30尾(7.4%)、呂宋鰻3尾(0.7)與西里伯斯鰻1尾(0.2%)，可見本種數量並不多，同時在野外的成魚可能更少，但是在菲律賓原生的應該有相當大量的族群。

呂宋鰻和鱸鰻外觀極為相似，但是可以經由背鰭起點(d=吻端至背鰭起點的距離)至肛門(a=吻端至肛門的距離)之間的距離，和身體全長(t=全長)的比例[p=(d-a)/t(%)]來區分，呂宋鰻的平均比(p=11.2%；變化範圍為9.4%~12.3%，n=8)比鱸鰻的平均比值(p=16.0%；變化範圍為14.1%~18.1%，n=8)有所差異；以及背鰭起點位於脊椎骨位置，前者約第24節處，後者約第21節處。

呂宋鰻和鱸鰻同屬於體色具有許多斑塊的淡水域鰻魚。本種肉食性，幼苗於台灣北部及中部野外有採獲記錄，成鰻則於蘭嶼有發現記錄。主要是在夏季裡洄游至菲律賓沿海地區，因此推估繁殖季節應該在冬春之際。在冬季發現的鰻苗數量則較少，繁殖場所在位置仍不清楚。

The Philippine mottled eel (Anguilla luzonensis) is an eel in the family Anguillidae. It was described by Shun Watanabe, Jun Aoyama, and Katsumi Tsukamoto in 2009. It is a tropical eel known from the Pinacanauan River system on Luzon Island (from which the species epithet is derived), in the Philippines. The eels spend most of their lives in freshwater but migrate to the ocean to breed.