Myctophum asperum Richardson 1845

Anal organs 13-14; males bear 5 luminous scales in supracaudal gland, females has 1-4 scales in infracaudal gland (Ref. 39633).

Oceanodromous. Migrating within oceans typically between spawning and different feeding areas, as tunas do. Migrations should be cyclical and predictable and cover more than 100 km.

Dorsal spines (total): 0; Dorsal soft rays (total): 12 - 14; Analspines: 0; Analsoft rays: 17 - 20

Neustonic to mesopelagic (Ref. 58302). High-oceanic, nyctoepipelagic at the surface and down to 125 m. Found between 425-750 m during the day. Sexually mature from about 65 mm (Ref. 4479). Proximate analysis (excluding head) reveals that lipid content is 2.0 % in fresh body weight and wax ester is 17.2 % in total lipids (Ref. 9193).

Myctophum asperum

This is a large tropical species (to 77 mm; Nafpaktitis et al., 1977) represented in the collections by a 53 mm subadult female taken with the Engel trawl in August.

分布於世界三大洋熱帶海域。臺灣則發現於東部及東沙群島周邊水域。

一般以底拖網捕獲，不具食用經濟價值，通常做為下雜魚用。

體延長，側扁，後部略細。頭中等大。吻短，前端鈍。眼大。口大，上頜骨狹長而延伸至前鰓蓋後緣，末端略擴大；上下頜呈絨毛狀齒帶。鰓蓋後上緣圓滑，不具鋸齒狀突起。體被大而薄圓鱗，易脫落；側線平直。背鰭單一，位於體中部，具軟條12-14(通常為13)，後部另具一脂鰭；臀鰭基底略等於背鰭基底，具軟條17-19(通常為18)；尾鰭叉形，尾鰭副鰭條柔軟。各部位之發光器位置於下：鼻部背位發光器(Dn)及鼻部腹位發光器(Vn)皆小而圓形；鰓蓋位發光器(Op)2個，位於前鰓蓋後緣下方，Op1較Op2小，均在眼眶下緣縱線之下；鰓被架位發光器(Br)3個；胸鰭上方發光器(PLO)，距側線比距胸鰭基部遠；胸鰭下方發光器(PVO)2個，兩者互為斜線排列；胸部發光器(PO)5個，PO5位置略昇高，位於腹鰭基的前上方；腹部發光器(VO)4個，水平排列；腹鰭上位發光器(VLO)位於腹鰭和側線之中間；臀鰭上方發光器(SAO)3個，三者排列略呈鈍角狀，SAO1在VO3及VO4之間的上方，SAO3緊臨在側線下緣；體後側位發光器(Pol)1個，在脂鰭下方，緊臨側線下緣；臀鰭前部發光器(AOa)7個，水平排列；臀鰭後部發光器(AOp)5-6個；尾鰭前位發光器(Prc)2個。尾部發光腺，雄魚的SUGL具4-6個，雌魚的INGL具1-2個發光鱗。

大洋性中層巡游魚類，具日夜垂直分布習性，白天一般棲息深度可達425-750公尺左右，晚上則上游至水深0-125公尺附近處覓食，以浮游生物為食。