AT A GLANCE
- Common Name: Thicklip Grey Mullet
- Scientific Name: Chelon labrosus
- Category: Fish
- Subcategory: Bony Fishes
- Range: Northeastern Atlantic Ocean from southwestern Norway and the British Isles south to Senegal, and throughout the Mediterranean and Black Seas
- Habitat Type: Coastal inshore waters, rocky breakwaters, harbor walls, shallow sandy estuaries, brackish lagoons, and lower freshwater river stretches
- IUCN Red List Status: Least Concern
- Lifespan: 20 to 25 years (exceptionally slow-growing and long-lived inshore fish)
- Diet: Herbivorous/Detritivorous (microscopic benthic algae, diatoms, epilithic biofilms, detritus, and small benthic invertebrates scraped from surfaces)
- Average Size/Weight: Length 40 to 60 cm (maximum up to 80 cm); weight 1.5 to 4.5 kg
- Key Defining Feature: Muscular, torpedo-shaped silvery inshore fish with large glistening scales and a famously deep, fleshy, tuberculated upper lip used to vacuum algae off rocks and harbor walls
Overview
The Thicklip Grey Mullet (Chelon labrosus) is a robust, silvery coastal teleost belonging to the mullet family Mugilidae. Abundant along the rocky coastlines, busy harbors, and brackish estuaries of western Europe and the Mediterranean, this powerful, torpedo-shaped fish is renowned for its wariness, intelligence, and remarkable dietary specializations. Equipped with a thick, rubbery upper lip and a muscular, gizzard-like stomach, it grazes on microscopic algal biofilms and organic silt like an underwater sheep.
Biology and Physical Characteristics
Chelon labrosus possesses an elongated, cylindrical, muscular body covered in large, firm, silvery cycloid scales that gleam with a metallic steel-blue sheen on the back and bright silver on the flanks, adorned with subtle, dark grey longitudinal lines. Its head is broad and dorsoventrally flattened. Its primary diagnostic hallmark is its heavy, fleshy, protruding upper lip, which is conspicuously thick and covered in several rows of tiny, sensitive sensory papillae or tubercles. The mouth is toothless, and the digestive system is modified for processing gritty plant matter: it possesses a heavily muscled, grinding stomach (gizzard) and an extraordinarily long digestive tract lined with spiral valves.
Behavior and Ecology
Thicklip Grey Mullets are highly gregarious inshore schooling fish that frequent shallow coastal water, harbor marinas, and tidal estuaries during warm summer months, often swimming with their dorsal fins cutting the surface. They feed by scraping epilithic algae, diatoms, and organic biofilms off concrete pier walls, rocky reefs, and muddy tidal flats using their thick, rubbery lips. They inhale mouthfuls of sediment, sift out nutritious organic matter using comb-like gill rakers, and expel indigestible sand and gravel out through their gill slits. Renowned for their exceptional speed and agility, they easily leap over floating obstacles and fishing nets when pursued.
Conservation and Human Impact
The Thicklip Grey Mullet is evaluated as Least Concern by the IUCN. It is abundant across the northeastern Atlantic and Mediterranean. Although widely targeted by commercial gillnetters and highly prized by European sport anglers for its immense fighting power on light tackle, its slow growth rate and late maturity make local stocks sensitive to over-exploitation in restricted estuarine nurseries.
Interesting Factoid
The Thicklip Grey Mullet has a muscular, stone-grinding gizzard inside its stomach just like a chicken, which it uses to pulverize sand grains and scrape nourishing green algae off harbor concrete walls.