SKATE FISH

Contents hide

1) Classification of Skate Fish

2) Geographical distribution

3) Habit and habitat

4) General Characteristics of Skate Fish

5) Economic importance

6) Special features

7) Identification

Classification of Skate Fish

Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
Group :- Craniata (Cranium with brain present.)
Sub phylum :- Vertebrata (Vertebral column present.)
Division :- Gnathostomata (Jaws and paired appendages present.)
Super Class :- Pisces (Paired fins, gills and skin with scales.)
Class :- Chondrichthyes (=Elasmobranchii) (Endoskeleton cartilaginous. Scales usually placoid. Notochord rudimentary, Spiral valve in intestine, opercula absent)
Sub-Class :- Elasmobranchii (Sharks and rays, Gills in separate clefts, cloaca present)
Order :- Rajiformes (Gills-slits ventral, Spiracles Present, Dorsal Fin on tail, if present, Vertebrae tectospondylous.)
Family :- Rajidae
Genus :- Raja (Skate)

Geographical distribution

Skate fish is found in almost all temperate sea waters. Most of the species belonging to the genus Raja are abundantly distributed in northern hemisphere, Arctic and Antarctic regions. Upper Jurassic to Recent.

Habit and habitat

Skate fish is marine, sluggish, bottom-dwelling fish. It is carnivorous, feeding on small fishes and crustaceans. They catch their prey by dropping over them and covering prey from all sides from their body and fins.

Classification of Skate Fish — Image Source Istock

General Characteristics of Skate Fish

Commonly, known as skate, measuring 2 to 3 meters n width.
Body is dorsoventrally flattened, rhomboidal and differentiated into anterior rhombic disk and a slender tail.
Colouration of upper surface resembles with sandy or gravelly environment of bottom.
Skin slender and provided with spines.
Body divided into head, trunk and tail.
Disc is made up by the head, trunk and confluent pectoral fins.
There are rows of tiny spines over the disc and a median row over the tail.
Head produced in a short snout with a pair of dorsal eyes.
Spiracles are found just below the eyes.
Ventral mouth provided with numerous sharp, rasping teeth for tearing the prey.
Slender tail distinctly demarcated from the rhombic disk. Fins-paired pectoral and pelvic fins present.
First dorsal fin and second dorsal fins near caudal fin.
Sexually dimorphic. Male is provided with a pair of claspers near the pelvic fin.
Oviparous, egg capsules four-homed.

Economic importance

Belonging to the family Rajidae, have notable economic importance due to their role in fisheries, trade, and ecological systems. Below is a detailed explanation of their economic significance:

1. Commercial Fisheries

Meat: They are harvested for their meat, which is consumed in various cuisines, particularly in Europe and Asia. The flesh is often used to make dishes such as skate wing fillets or soups.
Cartilage: The cartilage of skate fish is used in dietary supplements and traditional medicine for its purported health benefits, including joint health.
Bycatch Utilization: While often caught as bycatch, skate fish have gained commercial importance in some regions as a source of revenue.

2. Export Market

Their wings are a popular export item in the seafood industry, especially to countries with high demand for marine delicacies.
Processed skate products, such as dried or salted fish, add value to the export market.

3. Industrial Uses

Gelatin Production: The skin and cartilage of skate fish are occasionally used in the production of gelatin for food and industrial applications.
Fishmeal: Their byproducts are processed into fishmeal, which is used as feed in aquaculture and livestock industries.

4. Recreational and Ecotourism Value

Skate fish are sometimes featured in aquariums or ecotourism activities that promote marine biodiversity. Observing these unique creatures can attract visitors, contributing to local economies.

5. Scientific and Educational Value

Skate fish are commonly used in scientific research due to their relatively large size and ease of study. Research on their physiology and biology contributes to advancements in marine science, generating economic activity through research funding.

6. Cultural and Culinary Importance

In many coastal regions, skate fish are a staple of traditional diets and local markets, supporting small-scale fishers and communities.
Popular dishes, such as “raie au beurre noir” in French cuisine, highlight the culinary importance of skate fish.

Challenges and Sustainability

Overfishing and habitat degradation threaten skate populations, as they are slow to mature and reproduce. Some species are listed as vulnerable or endangered by conservation organizations.

Efforts to ensure sustainable exploitation include:

Regulated Fishing: Setting catch limits and protecting nursery areas to allow population recovery.
Marine Protected Areas: Preserving habitats to safeguard skate fish populations.
Alternative Livelihoods: Encouraging ecotourism and sustainable fisheries practices to reduce reliance on overfishing.

By balancing economic benefits with conservation measures, skate fish can continue to provide value while maintaining ecological integrity.

Special features

The pectorals tins are greatly expanded. They are endoskeletally supported and they extend along the lateral margins of the trunk from the pelvic fins upto the snout. Tail contains one median and two additional rows of small spines which inflict severe and irritating wound.