Endangered Animals: Invertebrates

Endangered Animals: Invertebrates — page 5 — EW Broad Sea Fan EX CR EN VU NT LC O Eunicella verrucosa The sea fan is a type of coral made up of many simple polyps joined together to form a colony in a fanlike pattern In common with a number of other marine invertebrates sea fans are beautiful and often form major attractions in submarine gardens A slow growing animal it is now under threat from overcollection Sea Sea fans are found in most of the world’s seas and oceans They may grow from shallow water down to the edge of the continental shelves and beyond they are even found at depths of about 13,000 feet 4,000 m in some parts of the world The broad sea fan occurs in the northeastern Atlantic and in the Mediterranean Sea Sea fans are attractive to souvenir hunters and thoughtless collecting by divers has recently reduced their populations around European coasts Sea fans are colonial that is they are made up of many individual polyps or zooids cylindrical forms joined together to form a colony Such a lifestyle is not DATA PANEL only Individual polyps arranged in double rows Diet Minute drifting plankton Breeding Details not well known planula free swimming larva results from fertilization of eggs attaches itself to a new substrate develops into a new colony which produces new zooids Related endangered species Probably many including red coral Corallium rubrum Status IUCN VU Broad sea fan Eunicella verrucosa Family Anthozoa World population Unknown Distribution Mediterranean Sea northeastern Atlantic off coasts of France Ireland U K Mauritania Morocco Portugal and Spain Habitat Rocks and hard surfaces from 49 ft 15 m downward to about 984 ft 300 m Size Colony grows to 11 8 in 30 cm in height Form Plantlike pink or white colony made up of polyps cylindrical sessile attached forms branches in 1 plane 8 unusual in the phylum Cnidaria to which they belong In the broad sea fan the polyps are arranged in two rows along the top and bottom of the branches Each polyp is a miniature animal in its own right and has its own mouth that also serves as its anus The mouth is surrounded by eight minute branching tentacles that are armed with stinging cells The tentacle form is a feature of the order Gorgonacea horny corals and is ideal for sieving the passing water currents to trap microscopic plankton Once collected the prey is manipulated into the gastric cavity via the mouth The gastric cavity extends into a number of tubes that increase the surface area for absorption and digestion of food products Many species of sea fan are virtually two dimensional and they grow so that the colony faces the prevailing currents at right angles thus maximizing their ability to catch prey Growth is slow so some sea fans are very old The colony is supported by an internal horny skeleton made up of a substance called gorgonin The tissue from which the polyps are made is further supported and protected by crystals of calcium carbonate that are embedded within it

Endangered Animals: Invertebrates — page 6 — BROAD SEA FAN Sperms and eggs develop inside the polyps and fertilization results in the development of a planula free swimming larva which escapes from the parent via its mouth and swims into the sea The planula has a simple structure and is covered with microscopic beating filaments cilia that drive it through the water However the planula can detect a suitable substratum usually rock on which to settle and develop into a new colony producing at first a founder polyp The polyp grows and produces more individual polyps and the necessary skeleton so that a colony structure is developed once again Vulnerability The emerging interest in marine conservation has led to an increased awareness of the effects of overcollection and human disturbance on some marine animals and plants Although it has not been significantly at risk in the past threats to the broad Sea fans come in a variety of colors from deep red yellow and orange to pink and white The polyps spread out their tentacles forming a net with which they catch plankton sea fan have risen recently with the increase in popularity of scuba diving The broad sea fan and its Mediterranean relative red coral Corallium rubrum are both slow growing so they are potentially more vulnerable Unlike the broad sea fan Corallium has been collected for centuries certainly since classical times A rich red color it was considered semiprecious and made into jewelry by the Greeks and Romans it was also thought to be able to ward off illnesses Corallium is now scarce in the Mediterranean and is found only at great depths Collection of the animal seems as yet to be poorly regulated 9

Endangered Animals: Invertebrates — page 7 — EX NT LC EW Giant Gippsland Earthworm CR EN Megascolides australis VU One of the largest earthworms in the world the giant Gippsland earthworm was discovered in 1878 Its large size and secretive habits have made it vulnerable to changes in land use resulting from the development of agricultural land from natural forest O the the giant Gippsland earthworm belongs to the Phylum Annelida the segmented worms which includes earthworms ragworms and leeches Named after the area of Australia that is its home it is found only in Gippsland a fertile region of southeastern Victoria that extends along the coast from Melbourne to the New South Wales border The giant Gippsland earthworm lives in permanent and elaborate burrows spending all its life underground There it feeds on the roots of plants and on other organic matter in the soil Most earthworm species deposit their waste material as obvious casts on the surface but this species leaves its cast material below ground Wales New South As a result of its exclusively underground life the giant Gippsland earthworm is difficult to study Consequently many aspects of its biology are unknown We do know that its body is Victoria AUSTRALIA divided up into between 300 to 500 visible segments The head and front third of the body are a dark purple color while the remainder behind the saddle is a pinkish gray Giant Gippsland earthworms are not easily kept in captivity and because of their large size and fragility they are easily damaged or killed by scientists and farmers alike Patchy Distribution The distribution of the giant Gippsland earthworm was previously much wider than it is today When European settlers arrived in the 18th century they transformed large areas of native forest into pasture for the dairy industry The disturbances associated with this proved very damaging to the worms Today giant Gippsland earthworms tend to be restricted to steep hillsides and valleys where the soils cannot be plowed Any activities that affect the moisture content and drainage of the soil can also be Tasmania Giant Gippsland earthworm Megascolides australis Family Megascolecidae World population Unknown Distribution Restricted to about 40 square miles 100 sq km of land in Gippsland Victoria Australia Habitat Burrows in organically rich soils DATA PANEL Size Length 31 in 80 cm diameter 0 8 in 2 cm Form Typical segmented worm a definite head and 300 500 segments each with chaetae bristles well developed respiratory and vascular system Diet Plant tissue and organic matter in soil Breeding Worms are hermaphrodite but 2 individuals are required for fertilization to occur Mating takes place in spring and early summer Individuals lay a single amber colored egg capsule containing 1 embryo which takes about 12 months to hatch The earthworms are presumed to reach adulthood about 4 5 years after hatching Adults may be long lived Related endangered species Washington giant earthworm Driloleirus americanus VU Oregon giant earthworm D macelfreshi VU Status IUCN VU 10

Endangered Animals: Invertebrates — page 8 — GIANT GIPPSLAND EARTHWORM The giant Gippsland earthworm like other earthworms is beneficial to the fertility of soil However more needs to be known about this elusive and fragile creature so that it can be protected bad news for the worms Building roads and dams trenching and laying cables are all damaging activities Natural seasonal fluctuations of moisture content govern the normal movement of the worms within the soil Recent surveys of southern and western Gippsland have shown that the giant earthworm is restricted to about 40 square miles 100 sq km of land in an area bounded approximately by Loch Korumburra and Warragul Much of this land is unsuitable and the giant earthworm’s distribution is very patchy The population density of the adult worms within the acceptable areas is usually low about two individuals per 35 cubic feet two per cubic meter The worms are mostly found in blue gray clay soils on flats by the banks of streams or along ditches and watercourses where the slopes face a southwesterly direction Like all earthworms the giant Gippsland worms have beneficial effects on the quality of the soil in which they live contributing to an increase in its organic content and assisting aeration and increasing fertility The giant Gippsland earthworm has become part of the folklore of southern Gippsland and many landowners speak with pride about its presence on their properties Conservation Conserving the giant Gippsland earthworm is difficult Retaining natural vegetation alongside streams as well as on steep slopes and in valleys and keeping out livestock by fencing the remaining earthworm habitats are both thought to be helpful measures However such strategies rely heavily on the cooperation of private landowners and farmers who may need help in identifying the parts of their properties that accommodate the giant earthworms One issue that has recently made this more difficult is the splitting up of larger properties into smaller ones used for small scale farming 11

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