A very large egg case, probably from a Big Skate (Raja binoculata), washed up on the beach on 5 February 2024.
Such an interesting design with those long curved ridges. Here are a couple more views:
And if you'd like to learn more, I wrote a longer post about a Big Skate egg case back in 2012 —
see "Just in case" on 7 March 2012.
Another amazing find & story, Jackie, Thank you.
ReplyDeleteWhat I don't understand:
"The egg cases are attached to the sea floor...."
So, does the gravid skate secrete some type of sticky glue when she 'births' the egg case (which preesumably is not growing any more) and the case becomes attached to the sea floor, whereupon she can swim away. This must occur in pretty deep water w/o much current or surrounding water movement if something that size needs to stay in place for 9 months. Or What??
Hi!
ReplyDeleteYes, I think that's about right. I tried to track down some info about the adhesive material, but all I could find were general references to glands that produce adhesive fibers. (Perhaps it's similar to mussel byssal threads that are released in liquid form but then stiffen quickly?)
Also true that the four prongs on the corners could help ensnare the egg case, but I'm guessing that wouldn't be enough to keep it in place.
Perhaps there's more info out there than I could find with only a quick search. If someone encounters some additional details about adhesion in skate egg cases, let us know!
:) Jackie