#benthic arthropods

[uncharismatic-fauna]

The Novel Norway Lobster

Nephrops norvegicus, better known as the Norway lobster, the Dublin Bay lobster, or in its culinary form as langoustine or scampi, is a small lobster found all along the European coast in the Atlantic ocean, from Norway and Iceland to Portugal, as well as the Adriatic Sea. They reside in muddy seabeds at up to 800 m (0.5 mi) below the surface.

Norway lobsters spend most of their time digging, maintaining, and hiding in their burrows, which are built about 20 to 30 cm (8 to 12 in) deep in the mud. When they do leave their burrows, it is only to forage or mate. Like many lobsters, N. norvegicus is an omnivore; they feed on anything they can find, including carrion, worms, fish, jellyfish, and other crustaceans. Predators include larger crustaceans, such as shore crabs, cod, stingrays, and small spotted catsharks.

The breeding period for Dublin Bay lobsters depends on the population's location and the temperature of the water, but generally takes place in late winter or spring. Females typically mate with 2-3 males, and carries 1000-5000 eggs under her tail for 8 to 9 months. After hatching, the planktonic larvae drift through the ocean for about two months, during which time they rise to the surface at night and descend to the ocean floor during the day. After settling on the bottom, juveniles undergo a molt before becoming fully mature. Afterwards, adults typically undergo 1-2 molts every year, and can live up to 10 years in the wild.

N. norvegicus is typically pink or orange in color, with a white underbelly and a darker stripe along the upper part of the claw. Adults can reach up to 20 cm (8 in) in length including the claws, which can comprise up to half that length. Its large eyes are exceptionally sensitive to light, and Norway lobsters are rarely seen during the daytime.

Conservation status: The Dublin Bay lobster is classified as Least Concern by the IUCN. It is commonly harvested for food, and populations are monitored closely.

Photos

Sue Scott

Institute of Marine Research

Hans Hillewaert

[uncharismatic-fauna]

The Shrimp-ly Wonderful Northern Shrimp

A common sight in grocery stores worldwide, Pandalus borealis is known by many names, including the northern shrimp, the pink shrimp, the deep-sea prawn, and the coldwater prawn. In fact, the species is not a prawn but a shrimp; the difference is that shrimp have one pair of legs ending in claws while prawns have three pairs. P. borealis can be found along muddy ocean floors throughout the northern Atlantic and Pacific-- though some regard the two populations as being separate species. Within this range, they typically inhabit cold waters, from -1  °C to 6 °C (30 °F to 43 °F).

As the name implies, pink shrimp are bright pink or red in color, though parts of their bodies are somewhat translucent. Males are smaller than females, at only 12 cm (4.7 in) to their 16 cm (6 in) in length. As a decapod, they have ten legs; the first three pairs, called the maxillipeds are used as mouth parts, while the rest are adapted for swimming.  The abdomen is divided into six segments, while the head and the thorax are fused together and protected by a thick shell known as the carapace. P. borealis’ eyes are compound eyes, like those of an insect, and are excellent at detecting movement in the dim light of the deep ocean. Additionally, their long antennae allow it to smell and taste chemicals in the water, assessing the location and suitability of prey.

The coldwater prawn lives in large schools of up to several hundred, though they have no set social structure and do not defend territories. They spend most of their time on the ocean floor, feeding on plankton and carrion. In the coldest parts of the Arctic, this makes them important members of the food web as they can recycle nutrients back into the system. In addition to widespread human predation, a number of octopi, seals, and fish are known to feed on the pink shrimp where available.

P. borealis breeds once a year, from July to September. Males release pheromones as they approach females to signal they are ready to breed, and afterwards the female will carry the stored sperm for up to eight months before fertilizing her eggs. In spring, while the water is still cold, egg-carrying females will migrate close to shore and lay their eggs-- up to 5,000 in a single clutch. The hatched larvae are all male, though they will go through six molts over the course of a year before migrating back to deeper waters and becoming sexually active. They will remain reproductive males for only about a year before molting again and transitioning to female; this is a type of hermaphroditism known as protandry. Individuals will spend the rest of their lives-- typically about eight years-- as a female.

Conservation status: Though they have not been evaluated by the IUCN, the pink shrimp is considered severely overfished in many parts of its native range. Trawling in particular poses a serious threat, as parts of a school not caught will still become stressed and die before reaching maturity. Ocean warming has also damaged populations, since this species thrives only in cold water.

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Photos

David Shale

Greenland Institute of Natural Resources

Erling Svenson