Cephalopods can be found in most marine habitats from shallow coastal waters (including tidepools) down to hadal depths. There are no freshwater cephalopod species, although a few such as the Atlantic brief squid (Lolliguncula brevis) can tolerate somewhat brackish conditions.
Here are some key concepts and terms for understanding cephalopod habitats.
Realms & Regions
Benthic realm - The ocean floor.
Pelagic realm - The water column above the ocean floor. Spalding et al. (2012) classified the world's upper pelagic waters (0-200m) into 37 provinces and seven biomes, which can provide useful context for understanding the global distribution patterns of many pelagic species.
Neritic region - The pelagic and benthic realms overlying the continental shelf.
Oceanic region - The pelagic and benthic realms beyond the continental shelf.
Basic Benthic Habitats
Intertidal zone - The region along the shoreline covered by the sea at high tide but exposed to air at low tide.
Continental shelf - The sea floor adjacent to a continent, extending to an average depth of about 180-200 m, where the continental slope begins. Spalding et al. (2007) classified the world's coastal and continental shelf waters into 12 realms, 62 provinces, and 232 ecoregions, which can provide useful context for understanding the global distribution patterns of many coastally occurring species.
Continental slope - The edge of the continent. The slope descends from the continental shelf and increases in depth more rapidly than the continental shelf does.
Bathyal zone - The benthic region along the upper continental slope between the edge of the continental shelf and the abyssal benthic region.
Abyssal plain - The vast expanses of soft-sediment covered seafloor, usually >2000m depth (average about 4000m worldwide).
Depth Zones
Epipelagic zone- The upper pelagic zone of the ocean. The zonation is based on the daytime distribution of animals. The depths of the zones depends on water clarity which varies between regions. In clear tropical and polar waters, the lower limit of this zone is about 350-400 m depth. Above this depth, there is enough light to make camouflage and concealment difficult, especially when animals are viewed from below.
Mesopelagic zone - The middle pelagic zone of the open ocean. In clear waters such as those near the Hawaiian Islands, the mesopelagic zone extends from about 400 m depth to 1200 m depth. The upper limit is defined by light levels which are low enough to allow animals to conceal themselves against the downwelling daylight with bioluminescence (counterillumination). The lower limit is defined as the depth limit for diel vertical migration. Sutton et al. (2017) classified the world's mesopelagic waters (approx. 200-1000m) into 33 ecoregions, which can provide useful context for understanding the global distribution patterns of many species that spend at least part of their life cycle in mesopelagic waters.
Bathypelagic zone - The deep pelagic zone of the open ocean; the zone beneath the mesopelagic zone, about 1000 to 4000m.
Abyssal zone - Deep-ocean habitats between 4000 and 6000m.
Hadal zone - The deepest pelagic and seafloor habitats, 6000 to nearly 11000m, including trenches. Among cephalopods, only the 'bigfin' squid (Magnapinna) and a few cirrate octopods have been observed at hadal depths (Jamieson & Vecchione, 2021).
REFERENCES
To cite this page: Young, R., Vecchione, M., Mangold, K., & Bolstad, K. [date page was accessed]. Cephalopod Ocean Habitats. CEPHREF. www.cephref.org/pages/cephalopod-ocean-habitats
This content has been modified from its original version on the Tree of Life web project.
References cited above:
- Jamieson, A. J., & Vecchione, M. (2022). Hadal cephalopods: first squid observation (Oegopsida, Magnapinnidae, Magnapinna sp.) and new records of finned octopods (Cirrata) at depths >6000 m in the Philippine Trench. Marine Biology, 169(1), 11.
- Spalding, M. D., Agostini, V. N., Rice, J., & Grant, S. M. (2012). Pelagic provinces of the world: A biogeographic classification of the world’s surface pelagic waters. Ocean & coastal management, 60, 19-30.
- Spalding, M. D., Fox, H. E., Allen, G. R., Davidson, N., Ferdaña, Z. A., Finlayson, M. A. X., ... & Robertson, J. (2007). Marine ecoregions of the world: a bioregionalization of coastal and shelf areas. BioScience, 57(7), 573-583.
- Sutton, T. T., Clark, M. R., Dunn, D. C., Halpin, P. N., Rogers, A. D., Guinotte, J., ... & Heino, M. (2017). A global biogeographic classification of the mesopelagic zone. Deep Sea Research Part I: Oceanographic Research Papers, 126, 85-102.