Galiteuthis glacialis facts for kids
Quick facts for kids Galiteuthis glacialis |
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| Ventral view of an adult specimen from the Ross Sea, with a mantle length of 321 mm (12.6 in) | |
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| Illustration of paralarvae (left: dorsal view, right: ventral view) | |
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Galiteuthis
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| Species: |
glacialis
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The Galiteuthis glacialis is a type of glass squid found in the cold waters near Antarctica. It belongs to the cranchiidae family, often called "glass squids" because of their clear bodies. These squids live only in the Antarctic region, especially in the Southern Ocean, around the Weddell Sea and the South Shetland Islands.
Galiteuthis glacialis is one of the most common and widespread squid species in the Antarctic. They live deep in the open ocean, in zones called the mesopelagic and bathypelagic layers. These squids are known for their daily vertical migration, moving up and down in the water. They can grow quite large, with their main body (mantle) reaching up to 500 mm (about 0.5 meters) long.
Contents
Where Does the Glass Squid Live?
Galiteuthis glacialis is mainly found in the Southern Ocean. They are common in the northern and eastern parts of the Weddell Sea. However, you'll find fewer of them in the southernmost areas. This species prefers the open ocean and the steep slopes of the Eastern Weddell Sea. They also live around the South Shetland Islands.
As these squids grow bigger, they tend to move into deeper waters. Young squids live between 300 and 1000 meters deep. Adult squids are usually found below 700 meters.
Daily Deep-Sea Journeys
These squids also show daily vertical movement patterns. This is called diurnal vertical migration. Baby squids, called paralarvae, and young squids live closer to the surface. They stay at depths of 300–400 meters during the day. At night, they swim up to 200–300 meters.
Older squids, both adolescents and adults, live much deeper. They are found in the lower mesopelagic and bathypelagic zones, at depths of 500–2500 meters. The reason they don't swim higher is because the shallow Antarctic waters are warmer and less salty. There's also a seasonal pattern: in summer, adult squids stay deep to avoid the warmer surface water. In fall, they might venture into shallower depths.
What Does the Glass Squid Look Like?
Galiteuthis glacialis has a see-through body. Adult squids have a jelly-like texture, while younger ones feel more leathery and muscular. Their body is narrow and covered with sharp bumps near the front and middle.
Their fin is shaped like a spear, with a short, thin needle-like end. They have a small head and large eyes. Each eye has two photophores, which are organs that can produce light. However, it's not confirmed if these specific photophores actually glow. This squid has a large stomach and a small caecum. This might be because food is scarce in the deep ocean. A larger stomach helps them store partially digested food. This stored energy can be used later, helping them survive when food is hard to find. All their body parts grow at a similar rate as they get bigger.
What Does the Glass Squid Eat and Who Eats It?
This squid is a meal for many animals. Sea birds, marine mammals, and fish all prey on it. Southern elephant seals eat some G. glacialis, and they eat both male and female adults.
Albatrosses, like black-browed and grey-headed albatrosses, also prefer adult squids. However, albatrosses can't dive deep enough to catch live adults. Instead, they eat squids that float to the surface. This happens when the squids' bodies start to break down, or when deep ocean currents bring them up. Parts of G. glacialis have also been found in the stomachs of a type of icefish that lives in the Southern Ocean.
Galiteuthis glacialis are opportunistic feeders. This means they eat whatever food is available to them. They likely prey on small animals called zooplankton that live in the mesopelagic zone. These zooplankton feed on sinking organic matter. Their common prey include crustaceans, chaetognatha (arrow worms), and small fish.
Life Cycle of the Glass Squid
Baby Galiteuthis glacialis, called paralarvae, hatch in the very deep bathypelagic layer. After hatching, they slowly float up to the upper layers of the water. They then spread out in the epipelagic and mostly mesopelagic zones.
As they start to mature, they begin their daily vertical migrations, moving up and down in the water column. Female squids lay their eggs in the deep bathypelagic zone. After laying eggs, the female's body tissues start to break down. This breakdown makes them more buoyant, causing them to float all the way to the surface of the water.
Reproduction
Spawning, or laying eggs, happens in deep water. This deep location helps protect the eggs from predators.
After a female squid successfully lays her eggs, her body tissues become gelatinous and lose muscle. She also becomes less hydrated and releases her eggs. This changes her natural buoyancy, making her float upwards towards the surface. Male squids do not go through this process. It's thought that males die after mating and sink to the seafloor. This might explain why scientists catch many more mature female squids than mature males in their nets.
