海鷂魚[ei] ray (fish)
井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
一天四海[ittenshikai] the world
雲海[unkai] sea of clouds
沿海[enkai] coast

遠海[enkai] deep sea
黄海[koukai] Yellow Sea
温海[atsumi] warm sea
海の幸[uminosachi] seafood

弁鰓類[bensairui] lamellibranches (i.e. bivalves)
鰓呼吸[erakokyuu] branchial respiration (breathing using gills)
鰓蓋[erabuta] gill cover
鰓孔[eraana] gill slit
鰓裂[sairetsu] gill slit

腸鰓類[chousairui] enteropneusts (hemichordates of class Enteropneusta)
翼鰓類[yokusairui] pterobranchs (hemichordates of class Pterobranchia)
海鰓[umiera] sea pen (any coelenterate of the family Pennatulidae or related families)
板鰓類[bansairui] elasmobranchs