benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
isopod
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...
Chaetiliidae
The Chaetiliidae are a family of isopod crustaceans in the suborder Valvifera
The Valvifera are marine isopod crustaceans. Valviferans are distinguished, however, by the flat, valve-like uropods which hinge laterally and fold inward beneath ...
. It is distributed along the coasts of the Arctic Ocean and of the northern Pacific Ocean. It is also found in the brackish Baltic Sea, where it is considered a glacial relict. Moreover, it is present in a number of North European lakes, including Ladoga, Vänern and Vättern. It has been introduced into the Black Sea.
''Saduria entomon'' is one of the largest crustaceans in the Baltic Sea. The largest ones are found in the depths of the
Gulf of Bothnia
The Gulf of Bothnia (; fi, Pohjanlahti; sv, Bottniska viken) is divided into the Bothnian Bay and Bothnian Sea, and it is the northernmost arm of the Baltic Sea, between Finland's west coast ( East Bothnia) and the Sweden's east coast (West ...
, reaching a maximum length of nearly . ''S. entomon'' are sexually dimorphic, with males growing larger and maturing at larger sizes than females. Most individuals die after reproduction, and the species might be functionally semelparous, but it is probably capable of
iteroparity
Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characteri ...
. Its lifespan is 3 years, possibly much longer.
''Saduria entomon'' is a predator that feeds on other benthic animals, such as ''
Monoporeia affinis
''Monoporeia affinis'', formerly referred to as ''Pontoporeia affinis'' ( el, Πόντος, ' = Pontus / Black Sea; , ' = to travel), is a small, yellowish benthic amphipod living in the Baltic Sea, the Arctic Sea and the lakes of the Nordic cou ...
''. It is also a
scavenger
Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...