Stephanie Guyotte, UR- Skate break

Raja eglanteria (clearnose skate) (from google)

Raja eglanteria or the clearnose skate is a common skate found off the east coast of the U.S. from Massachusetts to Florida. R. eglanteria migrate down to the warmer waters in the winter to escape to cold and to reproduce. R. eglanteria are oviparous meaning they lay eggs. during mating the male will bite the females pectoral fin to get a grip then will bend its beneath himself and the female, then we all know what happens next. The process can take up to four hours due to the consistence of the males sperm and the fact that the female can store sperm in their shell-secreting oviducal glands for up to tree months for later use. Two eggs are fertilized at once and are released when ready; the second will come out anywhere from minutes to hours after the first. The eggs of R. eglanteria will then plant themselves in the mud below but not fully submerged for after the blastodisc stage small "air" hole(s) open in the shell of the egg and R. eglanteria will circulate the water thru the egg with its forming tail. When R. eglanteria is ready or becomes too big (about 12 weeks) they will rip through the shell and be fully formed. The egg casing then get washed up on shore. The clearnose skate eggs are laid between December and May and a single female can produce up to 66 eggs in one season. Water temperature must be 20 degrees C or the eggs will not survive. Salinity must be 12ppt-35ppt (for adult for sure not sure about eggs).

Formation of blastodisc (b), cleavage(c-e), start of head
formation (f) (source2)  

Last stages of formation (source2)

Almost all of the information gathered about reproduction and skate eggs was obtained in captivity, this is because the clearnose skate in particular just make good specimens to study for their size, availability, and they are easily maintained. The thing is there is not much information about where clearnose skates lay eggs (other than off the coast of Florida) in the wild. I am going to try and see if there is a particular area where they like to lay eggs or if they just let them drop where they are. I have two possible methods; go out and find eggs and note location then clear them from the beach ( I will do this at several different beach locations) then go back the next day at the same time to the same area and try and find new eggs. This will tell me that those eggs have only been there no more than 24 hours, then taking into account tides, currents, and other factors try and calculate how far that egg could have traveled in 24 hours. I could then fish for clearnose skates in this area or muck around and try to find eggs in the water (without disturbing the eggs if possible). This approach has many variables that could make this very inaccurate such as the fact that the egg could have been in the water for days before washing ashore and just trying to calculate something moving through water is very difficult. My other approach is very similar but instead of trying to calculate where they came from, I could look at where the eggs are and are not found on the beach and see if a larger concentration is found in one area over another and again look at tides and currents then trace them back that way, then fish again. Looks like I will be having a beach filled spring break!





References:
1. http://www.flmnh.ufl.edu/index.php?cID=2110
2. https://link-springer-com.db06.linccweb.org/article/10.1007/s10641-007-9219-4