Maltese Skate

The Maltese skate is a relatively small skate in comparison to other skates in the Rajidae family. At adulthood, the total length ranges from 14–45 cm (5.5–17.7 in) for females and 10–52 cm (3.9–20.5 in) for males. The maximum length of a Maltese skate is around 50 cm (20 in), while other Rajidae skates can grow up to 120 cm (47 in) in length. The snout on its head is short, pronounced, and pointed. The front edges of the skate’s anterior (frontal) disc margins have a wavy (undulated) outline and the pectoral fins are rounded. This allows the skate to swim efficiently by generating oscillations to glide in the water. Skates have a laterally depressed, rounded pectoral disk shape that allows it to swim near the seafloor and bury itself in mud and sand. The tail length is slightly longer than the length of the disc and lacks spines between the two dorsal fins on the tail. There are 6-8 small spines around the eyes, which are referred to as orbital thorns. On the back of the head, there are 4 nuchal thorns. Around the nape and shoulder area, there is a small triangular patch of thorns. Running along the length of the tail to the first dorsal fin on the back, there are 3 to 5 irregular parallel rows of thorns. The underside, also referred to as the ventral surface, is smooth with some prickles along the anterior disc margin, which is located along the front edge. …

Sightings of the Maltese skate are extremely rare, only recorded in 20 hauls out of 6336 total in north Mediterranean broadscale surveys. In the 2012-2015 MEDITS surveys conducted by the General Fisheries Commission for the Mediterranean (GFCM), the Maltese skate was only found in two geographic sub-areas (GSAs): GSA16 and GSA22, which is the Strait of Sicily and the Aegean areas, respectively. Maltese skates are found in a wide range of depths, from the surface of the sea to as far down as 800 metres (2,620 ft). They are commonly found on the outer continental shelves and upper slopes from 400–800 metres (1,310–2,620 ft), in addition to muddy and sandy seabeds. Although sightings of the Maltese skate have been reported on the Algerian coast previously, no specimens were available for confirmation, which led to doubt that the species resided there. This may lead to speculation that the Maltese skate only occasionally appear in this area. The Maltese skate is reported to be restricted to the continental shelf of the Mediterranean Sea, but sightings of this skate in Greece is unlikely and must have been confused with the Cuckoo ray (Leucoraja naevus). Knowledge of habitat for endemic elasmobranchs, including the Maltese skate, is still limited and unknown. …

The Maltese skate diet consists largely of small benthic invertebrates, including crustaceans and plankton. The small, pointed rows of teeth in its inferior mouth allows it to capture prey with ease. Like other skates, they use a common feeding strategy that involves burying itself partially in the sand to camouflage itself before ambushing its prey. The morphology of the Maltese skate, including the depressed body shape and the spiracles allow the skate to effectively use this feeding strategy.

Like other species in the Rajidae family, the Maltese skate is iteroparous, meaning they reproduce multiple times throughout its life cycle. Annually, females deposit around 10-56 egg cases during their breeding season, which ranges from spring to autumn.

Skate egg cases are commonly referred to as “mermaid purses” and have the general appearance of a leathery, rectangular case made out of keratin. Maltese skate egg cases are about 4–8 centimetres (1.6–3.1 in) long and 2–6 centimetres (0.79–2.36 in) wide, but it varies based upon the size of the female and region. The color of the case is yellowish with brown hues. The length of the anterior (upper) apron is longer than the posterior (lower) apron. The intersecting anterior horns are thin and about 103.9% longer than the total egg case length, which is a diagnostic feature of Maltese skate cases. The anterior horns act as an anchor to the seafloor to prevent the egg case from drifting away. The posterior horns are a moderate length with similar thickness to the anterior horns, but do not intersect. It is common for chondrichthyes egg cases to have flexible lateral keels along the outer edge as structural reinforcement, but these are not present in Maltese skate egg cases. …