We need you to help:If you see any of the species mentioned below, send your record to [email protected]
Please include the following information in your message and if possible an image/photo:
- Include the of organism (if known) you have seen (see guide below on fish, invertebrates and algae)
- Send us a photo it is very important to allow us to verify the species, or in cases where you are unsure of the species name for our team to complete the identification on your behalf.
- Location (name and/or geographic coordinates, whether it is in coastal waters, offshore, stranded)
- Abundance (the number you sighted)
- When you observed the organism (while fishing, sailing, diving, swimming, walking)
We look forward to receiving your sightings of invasive species, thank you for your cooperation and contribution towards the database of invasive species in the Aegean Sea is greatly appreciated!
List of Species
1. Shrimp Scad (Alepes Djedaba)
Ellipsoid, compressed body; caudal fin yellow; black spot on upper margin of operculum
Habitat: pelagic, inshore waters
Size: Up to 40 cm, commonly around 25 cm
Impact: Form large schools and have few predators thus they create competition.
Origin: Indo-Pacific
2. Apogonichthyoides Pharaonis
Two distinct dorsal fins, three vertical black bars cross the gray-brown background, characteristic black 'eye-spot' on the flank, within the first bar
Habitat: Nocturnal, during the day hiding in caves and among seagrass
Size: Up to 10 cm
Impact: No evidence of competition, daily migration movements in and out of caves impact cave-associated invertebrate fauna.
Origin: Western Indian Ocean
3. Red Sea Hardyhead Silverside (Atherinomorus forskalii)
Broad silvery, mid-lateral band runs from the upper margin of the pectoral fin to the base of the tail fin. (Similar to Antherina boyeri)
Habitat: Shallow waters, close to the coast, near the surface, large schools
Size: Up to 15 cm, commonly 2-10 cm
Impact: Could have a positive impact as prey for larger species. Possible negative impact on crustaceans.
Origin: Red Sea
4. Blue-spotted Cornefish (Fistularia commersonii)
Elongated body, smooth skin, long tubular mouth with highly serrate ridges; grey body often with blue spots
Habitat: On sandy bottom, above seagrass meadows, always adjaent to rocky reef areas
Size: 115-120 cm
Impact: Voracious predator and aggressive in fish schools, may influence local fish communities.
Origin: Indo-Pacific, central Pacific
5. Silver-cheeked Toadfish (Lagocephalus sceleratus)
Elongated, slightly laterally compressed body; regular black dots on silvery grey back, white bottom; Inflate their bodies when threatened.
Habitat: Coastal habitats, on sandy bottoms and seagrass meadows, to a depth of 100 m
Size: Up to 110 cm, commonly 20-60 cm
Impact: Make up a huge amount of the fish biomass in Posidonia oceanica meadows and sandy areas in Rohodes. Poisonous flesh, thus health risk to the consumer.
Origin: Tropical Indo-West Pacific
6. Half-smooth Golden Putterfish (Lagocephalus spadiceus)
Elongated, slightly laterally compressed body; regular black dots on silvery grey back, white bottom; Inflate their bodies when threatened.
Habitat: Coastal habitats, on sandy bottoms and seagrass meadows, to a depth of 100 m
Size: Up to 40 cm, commonly 5-30 cm
Impact: Make up a huge amount of the fish biomass in Posidonia oceanica meadows and sandy areas in Rohodes. Poisonous flesh, thus health risk to the consumer.
Origin: Tropical Indo-West Pacific
7. Lagocephalus suezensis
Elongated, slightly laterally compressed body; regular black dots on silvery grey back, white bottom; Inflate their bodies when threatened.
Habitat: Coastal habitats, on sandy bottoms and seagrass meadows, to a depth of 100 m
Size: Up to 18 cm, commonly 7-15 cm
Impact: Make up a huge amount of the fish biomass in Posidonia oceanica meadows and sandy areas in Rohodes. Poisonous flesh, thus health risk to the consumer.
Origin: Tropical Indo-West Pacific
8. Randall's Threadfin Ream (Nemipterus randalli)
Ellipsoid, slightly compressed body; pinkish body; 3-4 pale yellow stripes along the sides; golden dot on pectoral base.
Habitat: Sandy and muddy sea beds, mainly found at 30-80 m depth
Size: Up to 30 cm, commonly 5-20 cm
Impact: Feeds on small benthic invertebrate, thus impact on abundance of invertebrates and their predators. Caught in large numbers by trawling.
Origin: Western Indian Ocean, including the Read Sea and the East African coast
9. African Sailfin Flyingfish (Parexocoetus mento)
Elongated body, compressed and rounded ventrally; blue back, silvery white belly; large greyish pectoral fins; can leap out of the water and glide the surface.
Habitat: In large schools in near.shore waters; never spreads to the open ocean.
Size: Up to 12 cm, commonly 7-10 cm
Impact: Unknown.
Origin: Indo-Pacific widespread from East Africa to Australia
10. Vanikoro Sweeper (Pempheris vanicolensis)
Body strongly compressed, triangular belly and large eyes. Brown bronze in colour with greenish sheen over the back. Pectoral fins yellow without black basal spot, tip of dorsal fin is black, and the base of the anal fin is often black.
Size: Up to 20 cm
Impact: Daily migration out of the cave impacts cave-associated invertebrate fauna.
Origin: Indo-West Pacific.
11. Striped Eel Catfish (Plotosus lineatus)
Body long and cylindrical, with eel-like tail. Brown with two narrow white stripes along each side: one above the eye and the other below. The belly is white.
Habitat: Prefers estuaries, lagoons and open coasts with sandy and muddy bottoms.
Size: 10-25 cm
Impact: Feeds mostly on benthic invertebrates, changing native community structure.
Origin: Indo-Pacific
12. Lionfish (Pterois miles)
Dorsal fin with long, strong, feathery spines. Wing-like side fins. Color varies from reddish to tan or grey with thin dark bars on the head and body. Fins spines are highly venomous.
Habitat: Areas with crevices or lagoons, often on the outer slopes of coral reefs.
Size: Up to 35 cm
Impact: These fish are able to spread quickly due to their long lifespan (15 years) and repetitive spawning (every four days)
Origin: Western Indo-Pacific
13. Redcoat (Sargocentron rubrum)
Alternating brownish red and silvery white stripes of equal width. Tail fin is deeply forked and the leading edge is red. Has one venomous spine on its cheek, and 1-2 spines level with the eye.
Habitat: Rocky areas and protected habitats at depths from 10-40 m. Nocturnal, spending most daylight hours in rock crevices.
Size: Usually 12-25 cm
Impact: Correlated with a decrease in numbers of native groupers and sparids.
Origin: Indo-West Pacific
14. Brushtooth Lizardfish (Saurida undosquamis)
Slender cylindrical body with large mouth and long jaws. Brown-beige with silvery white belly, and has a series of dark spots on the first dorsal fin ray and the upper edge of the tail fin.
Habitat: Sandy or muddy bottoms of coastal waters from 30-70 m, though down to 100 m deep.
Size: Normally 15-35 cm, though up to 50 cm.
Impact: Voracious predator, may compete for prey with native lizardfish.
Origin: Indo-West Pacific
15. Dusky Spinefoot (Siganus luridus)
Body is compressed and ellipsoid, with small scales. Dark brown to olive green with a touch of yellow on the fins. Has venomous spines on dorsal, anal, and pelvic fins.
Habitat: Occurs in small schools in shallow water, preferring hard bottoms of compacted sand with rock.
Size: 5-20 cm, max 30 cm
Impact: Can result in drastic decrease in seaweed formations due to herbivory
Origin: Western Indian Ocean and Red Sea
16. Marbled Spinefoot (Siganus rivulatus)
Ellipsoidal, compressed body covered in small scales. Body colour is brown to grey green and light-brown to yellow on the belly. Often has fine, faint yellow-gold stripes on the lower half of the body.
Habitat: Shallow waters, preferring hard bottoms of compacted sand with rock.
Size: 5-25 cm.
Impact: Can result in drastic decrease in seaweed formations due to herbivory
Origin: Western Indian Ocean and Red Sea
17. Reticulated Leatherjacket (Stephanolepis diaspros)
Highly compressed body with brown to olive green-grey colouring and darker markings.
Habitat: Lives in small groups in coastal rocky habitats usually covered in vegetation. Young individuals also feed in open waters on sandy and muddy substrates.
Size: 7-15 cm, though up to 25 cm
Impact: Habitat and prey preference overlaps with native species, therefore causing competition. Also, as an herbivore, S. diaspros impacts local faunal diversity
Origin: Western Indian Ocean
18. Yellowspotted Puffer (Torquigener flavimaculosus)
Grey-brown to olive green coloration and interweaving olive-grey patterns.
Habitat: Shallow waters over sandy substate where seagrass grows.
Size: 5-11 cm.
Impact: Competes with native species
Origin: Western Indian Ocean
19. Goldband Goatfish (Upeneus mollucensis)
Elongated, moderately compressed body. Has a rounded snout with two short, thin barbels. Dorsal colour is pinkish-red, and belly is white. One longitudinal yellow stripe runs from the eye to the tail.
Habitat: Coastal waters with muddy and sandy substrates at depths of 20-130 m. Forms large schools.
Size: 7-18 cm
Impact: Competes with native Mullidae species
Origin: Indo-West Pacific
20. Por's Goatfish (Upeneus pori)
Elongated, moderately compressed body. Has a rounded snout with two short, thin barbels. The back and sides of ths goatfish are mottled reddish-brown and the belly is white.
Habitat: Sandy, gravel and muddy seabeds up to 50 m deep.
Size: 5-14 cm.
Impact: Competes with native Mullidae species.
Origin: Western Indian Ocean
List of Species
1. Acrothamnion preissii
Loose clumps, rose-red in colour and highly branched. Attached to substrate by rhizoids.
Habitat: Seagrasses from shallow subtidal zones to nearly 40 m deep.
Size: From 0.5 to 1.5 cm
Impact: Largely unknown, but may outcompete or replace native algal species
Origin: Indo-Pacific
2. Harpoon Weed (Asparagopsis armata)
Has two morphologically different stages: the gametophyte stage is pale purplish-red, while the tetrasporophyte stage is brownish-red, filamentous, and highly branched.
Habitat: Epiphytic to algae, especially Corallina spp
Size: Up to 200 mm
Impact: Outcompetes native species for space and light.
Origin: Western Australia
3. Supreme Limu ( Asparagopsis taxiformis)
Is a species of red algae, with cosmopolitan distribution in tropical to warm temperate waters.
Habitat: A tropical/subtropical species
Size: No information
Impact: Unknown
Origin: Unknown
4. Grape Sand Moss (Caulerpa racemosa var. cylindracea)
One main stolon with coarse branchlike structures bearing clusters of miniature grapelike appendages.
Habitat: Intertidal zone to over 60 m deep
Size: From 5 to 30 cm
Impact: It out-competes native species and alters ecosystem structures.
Origin: South-western Australia
5. Killer Algae (Caulerpa taxifolia)
One main stolon with upright, feather-like fronds.
Habitat: Rocky, sandy, or muddy bottoms from surface to 80 m deep
Size: Up to 10 cm
Impact: Areas invaded by Caulerpa taxifolia have shown declines in overall biodiversity and fish biomass.
Origin: Indian Ocean
6. Green Sea Fingers(Codium fragile sp. fragile)
Consists of one to several erect fronds with cylindrical, spongy branches. Attached to substrate by spongy basal disc.
Habitat: Intertidal and shallow subtidal rocky bottoms, sheltered habitats such as harbours and bays
Size: From 15 to 20 cm
Impact: Traps sediments and eventually changes the nature of the substrate. Structure does not provide refuge for fish.
Origin: North Pacific Ocean and Japan
7. Lophocladia lallemandii
Red filaments, usually matted and intertwined with other algae.
Habitat: Epiphyte found on macroalgae, Posidonia oceanica, rock, coralligenous communities.
Size: Up to 15 cm
Impact: Aggressive growth leads to decrease in P. oceanica density, and can result in death of the seagrass.
Origin: Red See
8. Stypopodium schimperi
Thin, fan-shaped appendages with longitudinal divisions. Almost transpartent, with slight brown coloration
Habitat: Rocky substrates from 0-20 m deep, though sometimes down to 80 m
Size: Up to 30 cm
Impact: Unknown, though this algae has no known predators and tolerates varied local conditions.
Origin: Indian Ocean
9. Wormersleyella setacea
Filamentous and rose-red to brownish. Usually epiphytic and forms dense tufts.
Habitat: Below 15 m, prefers dimly lit habitats and can be found near coralligenous outcrops.
Size: Up to 1 cm high
Impact: Outcompetes macroalgae and invertebrates. Traps sediments, hindering settlement of native species and consequently reducing biodiversity and composition of local algal communities.
Origin: Hawaiian Islands
10. Halophila seagrass (Halophila stipulacea)
Rhizomes fixed to sand by roots, bearing pairs of leaves at regular intervals. Leaves have a serrated edge.
Habitat: Sand and mud substrates, tolerates wide range of environmental conditions
Size: Leaves are 3-6 cm long and 2.5-8 mm wide.
Impact: Can displace native seagrass such as Posidonia oceanica and Cymodocea nodosa.
Origin: Indian Ocean
List of Species
1. Nomad Jellyfish (Rhopilema nomadica)
Light blue with tiny granules on the bell. Hanging from the centre are eight large mouth-arms divided at mid-length into two ramifications with numerous long filaments.
Habitat: Dense aggregations in coastal areas during summer months, although it can also appear all year round.
Size: 40-60 cm.
Impact: Voracious predator that consumes vast amounts of shrimp, mollusc and fish larvae, and can cause major trophic cascades in the marine food web, with a resulting impact on biodiversity.
Origin: Indigenous to tropical warm waters of Indian and Pacific Oceans. Since 1970's it has been also found in Mediterranean Sea, where it entered via the Suez Canal
2. Spotted Sea Hare (Aplysia dactylomela)
Large sea slug without an external shell. Smooth, soft, pale green or yellow body with blacks rings
Habitat: Rocky and sandy substrates at depths of up to 40 m found in shallow waters with dense algal build-up
Size: up to 410 mm
Impact: The species is a grazer of algae and this may influence the composition and diversity of algal communities in a given location.
Origin: Atlantic origin: it spread naturally through the Gibraltar Strait
3. Asian Date Mussel (Arcuatula senhousia)
The surface of the shell is marked with red lines that look like rays extending toward the edge. The longest side of the shells is slightly concave. The shell is shiny and pale olive-green with purple concentric stripes that sometimes are also visible inside.
Habitat: Muddy bottoms of bays and estuaries, preferably in sheltered areas from the intertidal zone down to a depth of 20 m
Size: Adults can reach up to 3cm in length and 1cm in width.
Impact: Can change the physical structure of the bottom, dominating benthic communities and outcompeting other filter-feeding bivalves for food
Origin: Originally from the south-western Pacific, The main pathway of introduction is through transfer with bivalve seed stock for aquaculture purposes; this species can also be spread by ship’s ballast waters
4. Indo-Pacific Mussel (Brachidontes pharaonis)
Externally dark brown-black and internally tinged violet-black.
Habitat: Shallow and sheltered marine areas and in hypersaline waters (> 45 PSU).
Size: bivalve with a 40 mm shell
Impact: This species can deplete the phytoplankton concentration in the water column, constraining the growth of other filter-feeding animals.
Origin: From the Red Sea and Indian Ocean that was introduced into the Mediterranean after the opening of the Suez Canal in 1869
5. Ragged Sea Hare (Bursatella leachii)
Numerous long, branching, white papillae. A key distinctive feature is its grey-brown body with dark brown blotches on the white papillae and bright blue eye- spots scattered over the body
Habitat: Shallow, sheltered waters, often on sandy or muddy bottoms with Caulerpa prolifera.
Size: more than 10 cm
Impact: They are believed to adversely affect commercial shrimping operations.
Origin: Originally found in warm temperate and tropical waters throughout the world, this species was probably introduced into the Mediterranean through the Suez Canal
6. Jewel Box (Chama pacifica)
The shell is usually thick and irregularly rounded. The external valve surface bears short spines that curve out from the surface.
Habitat: Rocky shores and hard substrates, usually on exposed sites from the intertidal zone down to a few metres’ depth
Size: Up to 70 mm in height
Impact: Singly can form dense aggregations, producing solid reefs at some sites and completely replacing native species such as the European thorny oyster, Spondylus gaederopus.
Origin: Widespread in the Indo-West Pacific, its presence in the Mediterranean is due to the opening of the Suez Canal
7. Pacific Oyster (Crassostrea gigas)
Rough and irregular and usually elongated. The two valves are unequal with large, irregular, rounded radial folds.
Habitat: Rocky and muddy bottoms from the intertidal zone down to a depth of about 15 m in shallow, sheltered bays.
Size: 10-15 cm
Impact: Colonization by the Pacific oyster has resulted in ecological competition with native species in many places.
Origin: Native to the north-western Pacific. Introduced to north-western Europe by aquaculture during the industry’s boom in the 1960s
8. Common Slipper Shell (Crepidula fornicata)
Smooth, oval-shaped shell with irregular concentric growth lines. White, cream, yellow or pinkish with brown or red veins or spots
Habitat: Within sheltered coastal bays and estuaries. It settles on other shells or hard substrates on mud and sand-gravel bottoms down to depths of about 30m
Size: Up to 3 cm
Impact: High-density colonies have major effects on the macro-benthic fauna and flora, as they compete for food with other filter-feeding invertebrates and increase carbon release
Origin: Originally from the western Atlantic, spread via boat or in association with culture oyster spat
9. Black Pygmy Mussel (Xenostrobus securis)
Thin, elongated shell, almost triangular in shape, formed of two valves of similar shape and size. Shiny and smooth shell, with a sculpture of fine concentric lines
Habitat: Found exclusively in estuaries and lagoons, on any kind of submerged or partially emergent hard substratum or oyster shells
Size: Up to 2–3 cm length
Impact: Considered to be one of the worst invasive alien species in Europe, it can smother the native infaunal communities, may affect nutrient cycling, reducing the food available to other filter-feeders
Origin: Originally from the south-eastern Pacific, accidentally introduced with seed bivalves for aquaculture purposes, but it can also be spread in ships’ ballast waters
10. Rayed Pearl Oyster (Pinctada imbricata radiata)
Shell rounded and irregular in shape, the two valves being flattened and developing obliquely in one direction. On the upper surface irregular concentric ribs and along the edge are scaly spines
Habitat: Found at depths of 5–25 m attached to hard surfaces: rocks, nets, buoys and docks, as well as in seagrass meadows on sandy-muddy sediments
Size: Shell length is usually 5–6cm, sometimes up to 10cm
Impact: It can modify the structure of habitats and native communities. It may also potentially outcompete other filter-feeding native organisms for food and space
Origin: Originally from the eastern Indian Ocean, Arabian Gulf and Red Sea. The primary pathway of introduction was the opening of the Suez Canal
11. Veined Rapa Whelk (Rapana venosa)
Has a heavy, short, sculptured shell with a large inflated body whorl that gives it a spherical appearance. It is nearly as wide as it is long
Habitat: Lives at depths of 2–40 m on sandy and rocky mixed bottoms in marine and brackish estuarine
Size: 11–13 cm
Impact: It is a voracious predator of bivalve molluscs and may also compete with native species for space
Origin: Originally from Sea of Japan, Yellow Sea and East China Sea. Larvae are likely to have arrived in ships’ ballast water, while young whelks could also have been hidden amongst commercial bivalve seeds and been transferred to new farm seedling areas
12. Red Thorny Oyster (Spondylus spinosus)
Lower valve cemented to a hard surface. The upper valve is flat and covered with fine short spines. The outline of the shell is oval and irregular
Habitat: Occurs on rocky bottoms at depths of 2–40m
Size: Adults can be up to 12cm in width
Impact: It can completely replace native oyster species
Origin: Native to the Indo-Pacific and Red Sea, arrived via the Suez Canal and its further dissemination was assisted by ships
13. Japanese Carpet Shell ( Ruditapes philippinarum)
Shell formed of two valves of equal shape and size. Oval shell in outline, thick, and longer than high. Surface shows evident radial ribs, while the inside shell is smooth
Habitat: Generally found in estuaries and lagoons, on sandy and muddy bottoms, from the surface to a few metres’ depth
Size: Adults can reach up to 5cm in shell length
Impact: It can have a major impact on the macro- benthic fauna and flora, since it competes for food and space with other filter-feeding invertebrates
Origin: Native to the Indo-Pacific region, it was introduced for farming along the Atlantic coast of France to replace the native clam Ruditapes decussatus in 1972
14. Red-throated Ascidian (Herdmania momus)
Large, translucent, pink or red- coloured ascidian. Tiny calcareous spicules lie under the surface of the outer tunic and internal structures
Habitat: Smooth artificial substrates such as breakwaters, jetties and artificial reefs down to depths of 20 m
Size: Can grow up to 18cm in height
Impact: Like other ascidians, it can be a nuisance fouler on ships, recreational vessels and other submerged man-made structures
Origin: Tropical Indo-West Pacific species, common also in the Red Sea, including the Gulf of Suez and the Suez Canal
15. Blunt-spined Microcosmus (Microcosmus squamiger)
A globular tube with two short openings (siphons) on the top. It attaches to a hard substrate by a stalk
Habitat: Shallow littoral rocky habitats, particularly inside marinas, harbours and aquaculture facilities. It can also spread locally and colonize nearby natural rocky habitats
Size: 4 cm in height
Impact: Can form dense aggregations, becoming a major structure that colonizes all the available substrate, altering the native communities in the process
Origin: Native to south-east Australia and has now spread to temperate waters worldwide. Given its presence in harbours, marinas and aquaculture farms.
16. Kuruma Shrimp (Marsupenaeus japonicus)
Pale pink or blue; carapace is smooth and glossy without hairs; brownish transverse bars on the upper side of the abdomen
Habitat: Bays and inland seas, from the coastline to depths of about 90 m; on sandy, sandy-mud bottoms
Size: Males up to 17 cm Females up to 24 cm
Impact:Can intruduce parasites to native species
Origin: Indian and Western Pacific ocean
17. Specled Shrimp (Metapenaeus monoceros)
Covered with short hair like structures; pale grey body with dark brown spots; orange-red antennae
Habitat: Found up to a depth of 170 m, commonly in 10-30 m depth, on sandy, sandy-mud bottoms
Size: Males up to 15 cm Females up to 20 cm
Impact: Outcompetes native species for food and territory. Commercally important, caught by trawlers and beach seines
Origin: Western Indo-Pacific
18. Peregrine Shrimp (Metapenaeus stebbingi)
Smooth, cream coloured carapace speckled with rust-coloured spots; reddish antenna and tail margins
Habitat: Found up to a depth of 90 m, juveniles in shallow coastal waters; on sandy, sandy-mud bottoms;buried in the substrate in daytime and foraging at night
Size: Males up to 11 cm Females up to 14 cm
Impact: Competing for food resources, thus affecting native species
Origin: Western Indo-Pacific
19. Sally Lightfoot Crab (Percnon gibbesi)
Flat, square-shaped body with a smooth surface; brownish green carapace; long flattened legs banded with golden yellow rings; small claws in females, large unequal claws in males
Habitat: On rocky shorelines, in the crevices of rocks
Size: up to 3 cm across
Impact: Unclear
Origin: West and east coast of America, estern Atlantic