| Ecophysiology | Ecophysiology |
| Ectoparasitic | Ectoparasitic |
| EggClutchLocation | Egg, egg mass or clutch location |
| EggPropaguleSize | Egg or propagule size |
| EggSac | Egg sac |
| Eggs | Eggs |
| Elevation | Elevation |
| EnclosedCoast | Enclosed coast or embayment |
| Encrusting | Encrusting |
| Endangered | Endangered (EN) |
| Endoparasitic | Endoparasitic |
| Endophytic | Endophytic |
| Endoskeleton | Endoskeleton |
| Endozoic | Endozoic |
| Environment | Environment |
| EnvironmentalPosition | Environmental position |
| Ephyra | Ephyra |
| Epibenthic | Epibenthic |
| Epifaunal | Epifaunal |
| Epifloral | Epifloral |
| Epilithic | Epilithic |
| Epipelagic | Epipelagic (0-200 m) |
| Epipelic | Epipelic |
| Epiphytic | Epiphytic |
| Epizooic | Epizooic |
| Eradicated | Eradicated |
| Eradication unconfirmed | Eradication unconfirmed |
| Erect | Erect |
| Established | Established |
| Established and expanding | Established and expanding |
| Established and stable | Established and stable |
| Estuary | Estuary |
| Eulittoral | Littoral |
| EversiblePharynx | Eversible pharynx |
| Exoskeleton | Exoskeleton (including shells) |
| Exposed | Exposed |
| ExtentOfPhysicalDamageToPredominantAndSpecialHabitats | Extent of Physical Damage to Predominant and Special Habitats (BH3) |
| External | External |
| ExternalTube | External Tube |
| Extinct | Extinct (EX) |
| ExtinctInTheWild | Extinct in the Wild (EW) |
| Extirpated | Extirpated |
| ExtremelyExposed | Extremely exposed |
| ExtremelySheltered | Extremely sheltered |
| FAOASFISSpeciesForFisheryStatisticsPurposes | FAO-ASFIS: Species for Fishery Statistics Purposes |
| FaunalBeds | Faunal beds |
| FeaturesOther | Features or other substratum |
| Fecundity | Fecundity |
| Feeding | Feeding |
| FeedingApparatus | Feeding apparatus |
| FeedingMethodBehaviour | Feeding Method/Behaviour |
| Fertilization | Fertilization |
| FilerBasket | Filter basket |
| Filiform | Filiform |
| FineCleanSand | Fine clean sand |
| Fisheries: accidental as bait | Fisheries: accidental as bait |
| Fisheries: accidental with deliberate translocations of fish or shellfish | Fisheries: accidental with deliberate translocations of fish or shellfish |
| Fisheries: accidental with fishery products, packing or substrate | Fisheries: accidental with fishery products, packing or substrate |
| Fisheries: deliberate translocations of fish or shellfish to establish or support fishery | Fisheries: deliberate translocations of fish or shellfish to establish or support fishery |
| Fission | Fission |
| Flabellate | Flabellate |
| Flaccid | Flaccid |
| FlattenedEllipsoid | Flattened Ellipsoid |
| Flexibility | Flexibility |
| Floating | Floating |
| Fluctuating | Fluctuating |
| FlyerFlight | Flyer (Flight) |
| Foliose | Foliose |
| FollowingFishingBoats | Following Fishing Boats |
| FoodPiracy | Food Piracy |
| FoodTypeDiet | Food Type/Diet |
| FootPaddling | Foot Paddling |
| FootStirring | Foot Stirring |
| Forest | Forest |
| ForestForming | Forest-forming |
| ForkLength | Fork length (FL) |
| Fragile | Fragile |
| Fragility | Fragility |
| FreeLiving | Free living |
| FreeWaterColumn | Free or water column |
| Freshwater | Freshwater |
| FreshwaterSalinity | Freshwater |
| FunnelShaped | Funnel Shaped |
| GameteType | Gamete type |
| GenerationTime | Generation time |
| Genetic impacts: hybridisation and introgression | Genetic impacts: hybridisation and introgression |
| GillRakers | Gill rakers |
| Gills | Gills |
| Glider | Glider |
| Globose | Globose |
| Glochidium | Glochidium |
| GoettesLarva | Goette's larva |
| Gonochoristic | Gonochorisitc (dioecious) |
| Gorgonin | Gorgonin |
| Grasping | Grasping |
| GraspingClaws | Grasping claws |
| GraspingPaws | Grasping paws, hands, feet |
| GravelShingle | Gravel or shingle |
| GravellyMud | Gravelly mud |
| GravellyMuddySand | Gravelly muddy sand |
| GravellySand | Gravelly sand |
| Grazer | Grazer |
| GrazerBrowser | Grazer/Browser |
| GrazerFrondsBlades | Grazer (fronds/blades) |
| GrazerGrainsParticles | Grazer (grains / particles) |
| GrazerSurfaceSubstratum | Grazer (surface/substratum) |
| Gregarious | Gregarious |
| GreySealPupProduction | Grey seal pup production (M5) |
| GroundForaging | Ground Foraging |
| GrowthForm | Growth form (or type) |
| GrowthRate | Growth Rate |
| Habitat | Habitat |
| HabitatModification | Habitat modification |
| HabitatPreferences | Habitat Preferences |
| HabitatsDirective | Habitats Directive |
| HabitatsDirectiveAnnexI | Habitats Directive Annex I |
| HabitatsDirectiveAnnexII | Habitats Directive Annex II |
| HabitatsDirectiveAnnexIII | Habitats Directive Annex III |
| HabitatsDirectiveAnnexIV | Habitats Directive Annex IV |
| HabitatsDirectiveAnnexV | Habitats Directive Annex V |
| HabitatsDirectiveAnnexVI | Habitats Directive Annex VI |
| Hadobenthic | Hadobenthic (Hadal) |
| Hadopelagic | Hadopelagic (>6000 m) |
| HalfCone | Half cone |
| HalfConeFlattenedEllipsoid | Half cone with flattened ellipsoid |
| HalfParallelepiped | Half parallelepiped |
| HalfSphereDome | Half sphere (dome) |
| HaploidDiploid | Haploid-diploid (haplodiplontic) |
| Haplontic | Haplontic |
| Hard | Hard |
| HardImmobile | Immobile hard |
| HardMobile | Mobile hard |
| HardSubstrata | Rock (hard substrata) |
| Hawking | Hawking |
| HeightAboveSubstratum | Height (above substratum) |
| Herbivore | Herbivore |
| Heteromorphic | Heteromorphic |
| Heterotroph | Heterotroph |
| HighMagnesiumCalcite | High Magnesium Calcite |
| Host | Host |
| HoverDipping | Hover dipping |
| Hovering | Hovering |
| Human health | Human health |
| Hydrostatic | Hydrostatic skeleton |
| HyperSaline | Hyper-saline |
| Hyperbenthic | Hyperbenthic |
| IUCNRedList | IUCN Red List |
| IceAssociated | Ice-Associated |
| Impact | Impact |
| In captivity/cultivated | In captivity/cultivated |
| Independant (Free living) | Independant (free living) |
| Individual release: accidental release by individuals | Individual release: accidental release by individuals |
| Individual release: deliberate release by individuals | Individual release: deliberate release by individuals |
| Induces novel behavioural or eco-physiological responses | Induces novel behavioural or eco-physiological responses |
| Infaunal | Infaunal |
| Infralittoral | Infralittoral |
| InhalentSiphon | Inhalent siphon |
| Inquilinist | Inquilinist |
| Instar | Instar |
| Intermediary | Intermediary |
| Internal | Internal |
| Interstitial | Interstitial |
| Introduced Species Catalog | Introduced Species Catalog |
| Introduced country and/or sea area | Introduced country and/or sea area |
| Introduction unverified | Introduction unverified |
| Introvert | Introvert |
| Invasive | Invasive |
| Invasiveness | Invasiveness |
| Invasiveness Not specified | Invasiveness Not specified |
| Invasiveness Uncertain | Invasiveness Uncertain |
| Isogamous | Isogamous |
| Isomorphic | Isomorphic |
| Iteroparous | Iteroparous (polytely) |
| JetPropulsion | Jet propulsion |
| Jumper/Hopper | Jumper/Hopper |
| Juvenile | Juvenile |
| Juveniles | Juveniles |
| Keratinous | Keratinous |
| Kleptoparasitism | Kleptoparasitism |
| Lagoon | Isolated saline water (lagoon) |
| Lanceolate | Lanceolate |
| LargeBoulders | Large or very large boulders |
| LargeInsectColonies | Large (insect colonies) |
| Larva | Larva |
| LarvalJuvenileDevelopment | Larval and juvenile development |
| LarvalSettlement | Larval settlement period |
| LarvalStageDuration | Duration of larval stage |
| LarvalSttlementSubstratum | Larval settlement substratum |
| LeastConcern | Least Concern (LC) |
| Lecithotrophic | Lecithotrophic |
| LifeCycle | Life cycle |
| LifeSpan | Life span |
| Lifehistory | Life history |
| Lifestage | Life stages |
| Lithotomous | Lithotomous |
| Locally common | Locally common |
| Location Type | Location Type |
| Lophophore | Lophophore |
| Loss of aquaculture/commercial/recreational harvest or gain | Loss of aquaculture/commercial/recreational harvest or gain |
| Loss of public/tourist amenity | Loss of public/tourist amenity |
