Latin name

Ammodytes marinus

Other name

Lesser sand-eel

Identification

The Raitt's sand eel has a pointed jaw, with the lower jaw extending farther than the upper jaw. There are no scales on the median stripe in front of the dorsal fin or on the musculature at the base of the caudal fin. The scales on its belly are loosely arranged and lack chevrons. It has 65-75 vertebrae. The pores on the lateral lines are arranged in a line along unbranched channels.

Features of fish fins

Dorsal spines (total): 0; Dorsal soft rays (total): 56 - 63; Anal soft rays: 29 - 33. 

These fish have a short caudal fin with a deep bifurcation. They also have a long, low dorsal fin that runs almost along the entire body and is twice as long as the caudal fin. The edges of the dorsal and anal fins are straight with equal-length rays.

Fish colouring

Raitt's sand eels are completely silvery with darker scales on their backs. Unlike many other fish, the scales on their underside are not arranged in a distinct pattern.

Distribution

They are widespread in the northeastern Atlantic Ocean, especially in the North Sea. They inhabit both the open ocean and coastal waters. Due to climate change, the southern limit of their range is predicted to move further north in the future. These fish thrive in cooler waters and may migrate northward to escape rising sea temperatures.

Habitat

This marine benthopelagic species prefers a temperate climate and brackish waters. They live in habitats ranging from 10 to 150 meters deep, usually in the upper 10 to 15 meters. They spend most of the year hiding from predators in the sandy sediments of the seabed. They also live among rocks and in algae thickets. Sandbanks are the most important habitat because they are used for breeding, spawning, and resting. They prefer to live in rough areas of the ocean and do not go below 100 meters.

Raitt's sand eels have very specific habitat requirements. They specialize in living in waters that are high in oxygen but low in silt and clay. These requirements mean that the fish are found in isolated patches throughout the North Atlantic rather than in one continuous population.

Size

This small, elongated fish usually grows to about 20 cm in length. This species' maximum length is 25 cm.

Behavior

This gregarious species is typically territorial and burrowing. They are most active during periods of strong tidal currents, when they leave their burrows and form large swarms. In low-light conditions, such as at night or in winter, they burrow to the bottom.

They prefer to swim in open water and burrow into the sand to avoid predators. When not hiding in burrows, they live in shallow water. They spend most of the winter burrowing in bottom sediments but come out into open water between March and June to feed as prey becomes more abundant. Even during the summer months, when sand eels come out to feed, they hide in the sand at night.

Food and feeding habits

This species of fish feeds mainly on zooplankton. By consuming zooplankton, they serve as a link to predators in higher trophic levels that feed on sand eels.

Reproduction

They breed in December and January when they temporarily leave their winter burrows in the sediment. The females lay their eggs in the sand and incubate them until they hatch in February and March. The hatched sand eels live in open water above the sediment until they undergo metamorphosis. Then, they return to burrows in the sediment. Most Raitt's sand eels live only three to four years due to their high natural mortality rate.

Fishing

This species is important for commercial fishing. However, this fishery is difficult to manage due to a lack of population data and regular fluctuations in population size. Catch cannot be predicted due to the volatility of the fishery. It is harvested using a net with a very small mesh size, which often catches other larger species.

Relationship with a person

Harmless. They are used to produce fish oil and fishmeal. Their high lipid content makes them ideal for this purpose.