- labial
- lachrymal plate
- LACM
- lagoon
- lake
- lamella
- lampridiformes
- lanceolate
- lanternfishes
- larva
- laterad
- lateral
- lateral line
- lateroventrally
- lectotype
- length
- leptocephalus
- life history
- life-cycle
- ligament
- limb
- limes
- lip
- lipids
- littoral
- lobate
- lobe
- local
- longitudinal
- LS
- luminescent
- luminous organs
- lunate