Skate Fish Introduction, Morphology & it's Characteristics.

Skate fish, also known simply as skates, are cartilaginous fish belonging to the family Rajidae. They are found in oceans worldwide, primarily in temperate and cold waters. Skates have a flattened body with large pectoral fins that resemble wings, allowing them to "fly" gracefully through the water. They are bottom-dwellers, often found on sandy or muddy seabeds, where they feed on small fish, crustaceans, and mollusks. Skates are known for their unique reproductive strategy, with females laying eggs in leathery egg cases known as mermaids' purses. They are commercially fished for their meat, which is firm and white, resembling that of other types of seafood like scallops or crab. However, some species of skates are vulnerable to overfishing and habitat degradation, highlighting the need for sustainable management practices.

1. University of Chakwal, Pakistan

2. DEPARTMENT OF ZOOLOGY
PRESENTED BY: ALISHBA BATOOL
REG NO: 20M-UOC/ZOL-21
BS-ZOOLOGY
SESSION 2020-2024
COURSE TITLE: ICHTHYOLOGY
SUBMITTED TO: DR. SYEDA NADIA AHMAD
TOPIC: RAJIDAE (SKATES FISH)

3. THE SKATE
FISH
ALISHBA BATOOL

4. CONTENTS
1 2 3 4 5
Taxonomy Distribution Importance Interesting
Facts
Unique Facts
6
Morphology
7
Behavior

5. Introduction
Skatefishesarecartilaginousfishes
belongingtothefamilyRajidae.They
arecloselyrelatedtoraysandsharks.
Skateshaveaflatbodywithwing-like
fins,andtheytypicallyinhabitsandyor
muddybottomsincoastalwaters.

6. Taxonomy of Skate
Fishes
•Kingdom: Animalia
•Phylum: Chordata
•Class: Chondrichthyes
•Subclass: Elasmobranchii
•Order: Rajiformes
•Family: Rajidae

7. Distribution of Skate Fishes
•GlobalReach:Skatesarecosmopolitan,meaningthey'refoundinmost
partsoftheworld'soceans.
•SaltyOnly:Skatesareexclusivelysaltwaterfish.
•Temperature:Skatestendtofavorcoolerwaters.Theyaremorediverse
inhigherlatitudesanddeeperwaters,withapreferenceforcoolwaters.
•Habitat:Skatesarebottom-dwellingfish,meaningtheyliveonthe
seafloor.Differentskatespeciescanbefoundinavarietyofhabitats
includingsoft-sedimentseafloors,rockyreefs,andkelpforests.

8. Importance of Skate Fishes
•Ecological Importance
•Scientific Importance
•Economic Importance
•Research and Significance
•Cultural Significance
•Nutrient Cycling

9. Interesting Facts
•They are electrical Communicators.
•They have more species than you think.
•They are Deep-sea dwellers.
•They are underwater detectives.
•They have fashionable foodies.
•They have layers on their eggs.

10. Unique Facts
•Lumbering Liver
•Mermaid's Purse
•Thorny Defense
•Masters of Disguise
•Elegant Gliders

11. Morphology of Skate Fishes
President Chief Executive Officer Chief Operations Officer VP Marketing
•Mouth
•Scales
•Fins

12. Scales
•Develop winning strategies to keep ahead of the competition
•Capitalize on low-hanging fruit to identify a ballpark value
Skateshaveplacoidscales.Thesescalesarehomologoustoteeth,
Eachplacoidscalehasaflattenedbaseembeddedintheskinanda
pointedcuspthatprojectsoutwards.Thecuspsareangledbackwards,
creatingaroughtexturethathelpsprotecttheskatefrompredatorsand
abrasionsasitglidesacrosstheseafloor.

13. Mouth
The mouth of a skate is located on the ventral side of the body The mouth is
lined with small, sharp teeth that help skates crush and tear through their prey.
There are some additional interesting features of a skate's mouth
•Sensory Pits: Around the mouth, skates have clusters of small pits called
electroreceptors. These pits can detect weak electric fields emitted by buried
prey, aiding skates in locating food.
•Labial Cartilages: Projecting flaps of cartilage around the mouth help
channel food towards the mouth.

14. Fins
The fins on a skate are:
•First and Second Dorsal Fins: Located on the back of the skate
these fins help with stability and maneuvering.
•Caudal Fin: The tail fin, used for steering and propulsion.
•Pelvic Fins: Paired fins located on the underside of the body,
near the vent.
These fins aid in and stability.

15. Behavior of Skate Fishes
•Parental Behavior
•Migratory Behavior

16. Parental Behavior
Skatesareoviparous,meaningtheylayeggs.Theeggsarefertilizedinternallyandthen
depositedontheseafloorinaleatherycasingoftencalledamermaid'spurse.Theembryo
developsinsidethepurseforseveralmonths,upto15monthsinsomespecies,beforehatching.
Unlikemanyfishthatsimplyscattertheireggsandleavethemtofendforthemselves,skate
eggshaveastickyfilamentthatallowsthemtoattachtoseaweedorotherobjectsonthe
seabed.Thishelpstoprotectthemfrompredatorsandensurestheystayinasuitable
environmentfordevelopment.Oncehatched,theyoungskatesareminiatureversionsofthe
adultsandareindependentfromthemomenttheyemergefromtheeggcase.

17. Migratory Behavior
•Unliketheircloserelativesthestingrays,skatesarenothighlymigratoryfish.They
tendtostayclosetotheseabedintheareastheyinhabit.However,somespeciesdo
exhibitseasonalmovements.Forexample,thebarndoorskate(Dipturuslaevis)is
knowntomigratetodeeperwatersinthewintertoreproduce.
•Skatesusetheirwing-likepectoralfinsto"fly"throughthewater,buttheyarenotthe
strongestswimmers.Thisiswhytheytendtostayclosetothebottomwheretheycan
restandavoidpredators.

18. 18
Conclusion
Skatefishesareadiversegroupknownfortheirflattenedbodies
anduniquereproductivestrategies.Inconclusion,thesefascinating
creaturesplayimportantrolesinmarineecosystems,servingas
bothpredatorsandprey.However,manyskatespeciesfacethreats
fromoverfishingandhabitatdestruction,highlightingtheneedfor
conservationeffortstoensuretheirsurvivalandthehealthof
marineecosystems.

19. References
•Ebert,D.A.,&Sulikowski,J.A.(2019).Preface:Distributionofskates.Distribution
ofSkates,1-4.
•Serra-Pereira,B.,Erzini,K.,Maia,C.,&Figueiredo,I.(2020).Importanceofessential
fishskatesbasedonfishers’knowledge.Environmentalmanagement,53,985-998.
•Ebert,D.A.,&Compagno,L.J.(2021).Biodiversityandsystematicsofskates
(Chondrichthyes:Rajiformes:Rajoidei).Biologyofskates,5-18.
•Soares,K.D.,Moreira,R.A.,&Gomes,U.L.(2021).PhylogenyofthetribeRiorajini
withcommentsonthemorphologicalcharacterevolutionwithinRajiformes
(Chondrichthyes,Batoidea).ZoologicaScripta,52(6),606-628.
•Mulas,A.,Bellodi,A.,Cannas,R.,Cau,A.,Cuccu,D.,Marongiu,M.F.,...&Follesa,
M.C.(2020).DietandbehaviouroflongnosedskatefishesJournalofFishBiology,
86(1),121-138.