Depth
Maja · Marine Life

Lesser Spider Crab

Maja crispata

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Reef & Open
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Genus Maja
Species crispata

Crustacean

Identification & Biology

  • IdentificationSimilar to the European spider crab but smaller, with a more rounded, less elongated carapace. Covered in fine hairs used to attach camouflage material. Legs are long and slender relative to body size. Reddish-brown to yellowish.
  • SizeCarapace length up to 8 cm. Leg span up to 25 cm.
  • Social HabitMostly solitary. Decorates its shell with algae and sponge fragments for camouflage, similar to its larger relative.
  • HabitatRocky reefs, seagrass meadows, and mixed substrates with algal cover. More tolerant of varied habitats than the larger spider crab.
  • Depth0 to 100 m. Common in the shallows to about 30 m.
  • Feeds OnAlgae, detritus, and small invertebrates. Primarily a grazer.
  • DistributionMediterranean Sea and adjacent eastern Atlantic coast. Common in Maltese waters.
  • DescriptionMaja crispata is frequently encountered on rocky reefs in Malta, often so well camouflaged with attached algae and sponge that it is almost invisible against the reef. It is smaller and more commonly seen than the European spider crab. Look carefully at what appears to be a small clump of algae on the reef and you may find it looking back at you.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting reef & open environments. Active from the surface down to 40m depth.

Where Malta divers have spotted this species

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Sightings are logged by divers using our What Did You See? dive-log tool. View the full live sightings map.

Detail

Preferred Environment

Reef & Open habitats, typically at depths of 0-40m. Most commonly encountered by divers at the shallower end of its range.

Encounter Tips

Best approached slowly and calmly. Avoid casting shadows directly over the animal. Neutral buoyancy and patience increase encounter success significantly.

Lesser Spider Crab species card

Biology

Behaviour & Diet

Feeding Strategy

Omnivore that feeds on algae, detritus, and small encrusting organisms. Uses its slender chelipeds to pick food from rocky surfaces and Posidonia beds.

Omnivorous picker

Reproduction

Females produce small egg clutches carried beneath the abdomen. Breeding occurs primarily during spring and summer in the Mediterranean.

Seasonal spawning

Behaviour & Defence

A master of decoration, it attaches living algae and other organisms to the hooked setae on its carapace to break up its outline. Remains motionless when disturbed, relying on this camouflage.

Decorator camouflage

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Maja crispata. All are accessible on a guided dive with diveshack.

5-30m
North Malta

Cirkewwa

Rocky reef with caves, arches and ledges hosting a rich diversity of reef species.

View dive site ›
5-50m
Gozo

Blue Hole

One of the Med's most famous reef dive sites. Rocky walls and archways covered in life.

View dive site ›
18-36m
South Malta

Um El Faroud

The wreck lies on a sandy bottom surrounded by rocky reef -- a diverse habitat attracting reef species.

View dive site ›
IUCN Red List Least Concern

Conservation Status

This species is assessed as Least Concern on the IUCN Red List. Mediterranean populations face ongoing pressure from fishing activity, habitat degradation, and climate-driven changes to prey availability.

Source: iNaturalist Guide #888
by Lesley Clements (CC BY-SA)
diveshack Mediterranean Marine Life guide