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 the Ancient Greek word (), meaning "the depths". ...
isopod
Isopoda is an Order (biology), order of crustaceans. Members of this group are called isopods and include both Aquatic animal, aquatic species and Terrestrial animal, terrestrial species such as woodlice. All have rigid, segmented exoskeletons ...
crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
of the family Chaetiliidae. It is distributed along the coasts of the
Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...
and of the northern
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...
. It is also found in the brackish
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
, where it is considered a glacial
relict
A relict is a surviving remnant of a natural phenomenon.
Biology
A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas.
Geology and geomorphology
In geology, a r ...
. Moreover, it is present in a number of North European lakes, including Ladoga,
Vänern
Vänern ( , , ) is the largest lake in Sweden, the largest lake in the European Union and the third-largest lake in Europe after Ladoga and Onega in Russia. It is located in the provinces of Västergötland, Dalsland, and Värmland in the sou ...
and
Vättern
Vättern ( , ) is the second-largest lake in Sweden, after Vänern, and the sixth-largest lake in Europe. It is a long, finger-shaped body of fresh water in south central Sweden, to the southeast of Vänern, pointing at the tip of Scandinavia. ...
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
.
Biology
''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 (; ; ) is divided into the Bothnian Bay and the Bothnian Sea, and it is the northernmost arm of the Baltic Sea, between Finland's west coast ( East Bothnia) and the northern part of Sweden's east coast ( West Bothnia an ...
, 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
Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous ...
, but it is probably capable of iteroparity. Its lifespan is 3 years, possibly much longer.
''Saduria entomon'' is a
predator
Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...
that feeds on other benthic animals, such as ''
Monoporeia affinis
''Monoporeia affinis'', (syn. ''Pontoporeia affinis'') (, ' = Pontus (region), Pontus / Black Sea; , ' = to travel), is a small, yellowish benthos, benthic amphipod living in the Baltic Sea, the Arctic Sea and the lakes of the Nordic countries.
...
''. It is also a
scavenger
Scavengers are animals that consume Corpse decomposition, 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 he ...
and a
cannibal
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecology, ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is also well ...