AT A GLANCE
- Common Name: Grey Gurnard
- Scientific Name: Eutrigla gurnardus
- Category: Fish
- Subcategory: Bony Fishes
- Range: Eastern Atlantic Ocean, from Iceland, northern Norway, and the Baltic Sea south around the British Isles to Morocco, and throughout the Mediterranean and Black Seas
- Habitat Type: Demersal coastal waters, sandy seabeds, gravel plains, and muddy continental shelves from shallow coastal bays down to 150 meters depth
- IUCN Red List Status: Least Concern
- Lifespan: 6 to 10 years
- Diet: Carnivorous/Benthic (small bottom-dwelling crustaceans such as brown shrimps and crabs, alongside sandeels, gobies, and marine worms)
- Average Size/Weight: Length 20 to 30 cm (maximum up to 45 cm); weight 200 to 800 g
- Key Defining Feature: Armored bottom-dwelling marine fish with a large spiny head, large wing-like pectoral fins, and three free finger-like walking rays used to literally walk along the seabed and feel for food
Overview
The Grey Gurnard (Eutrigla gurnardus) is a bizarre and fascinating bottom-dwelling teleost belonging to the gurnard or sea robin family Triglidae. Abundant across the sandy coastal shelves of the northeastern Atlantic and Mediterranean, this extraordinary armored fish looks like an underwater creature from science fiction. Equipped with a heavily armored bony head, enormous translucent pectoral fins that fan out like wings, and three modified ‘walking fingers’ on each side, it literally walks along the sandy ocean floor while probing for buried food and grunting audibly like a pig.
Biology and Physical Characteristics
Eutrigla gurnardus has a tapered, elongated body encased in small ctenoid scales with a distinct, sharply spiny lateral line. Its head is massive, triangular, and completely encased in rough bony armor plates armed with sharp spines. Its pectoral fins are divided into two distinct components: the upper portion forms a large, fan-shaped wing used for gliding above the sand, while the lower three rays are completely detached, thickened, and mobile, functioning as independent ‘walking legs.’ These finger rays are densely packed with chemosensory cells that taste and smell the seabed as the fish walks. Coloration is typically dull greyish-brown to olive-tan on the back, speckled with fine white dots, with a pale white belly.
Behavior and Ecology
Grey Gurnards are benthic hunters that walk methodically across sandy and gravelly seabeds using their finger-like rays. As they walk, they probe the sediment; the moment a walking ray touches a hidden brown shrimp or sandeel, the fish pounces forward and engulfs it in its wide mouth. Gurnards are famous for mechanical grunting, croaking, or barking sounds, which gave them the old French name ‘gournard’ (the grunter).
Conservation and Human Impact
The Grey Gurnard is classified as Least Concern on the IUCN Red List. It is one of the most abundant benthic fish species in the North Sea and Celtic Sea, with a biomass numbering in the hundreds of millions. Historically discarded as bycatch by commercial trawlers targeting cod and plaice, it is increasingly marketed as a sustainable, firm-fleshed seafood choice in European markets.
Interesting Factoid
The Grey Gurnard can literally walk across the seabed using three finger-like leg rays on each side of its body, and when lifted out of the water, it vibrates its swim bladder to make loud, indignant grunting sounds like a miniature pig.