Sharks and Rays in Aquariums Gaining an understanding of how to keep these fishes in captive saltwater systems    New Print and eBook on Amazon   by Robert (Bob) Fenner

Trick question? Re Batoid hybridization 2/1/07 Hi I have a blue dot whiptail ray (MALE) and a round Stingray ( FEMALE) can they Have Babies? Love mom <Yes, but not with/by each other. BobF>

Manta ray eggs on Oregon coast? Hi, Answer People! <Whassup, question person?!?> My friend found an egg sac on the Oregon central coast last weekend. She was told it was a Manta Ray egg.   <Ha! Did her date tell her this trying to impress her with the size of his... brain (for lack of a Lincoln with black tinted windows... Ha!)? I sure hope not for his sake... Manta rays are ovoviparous... that is to say: live-bearing. All of the big Elasmobranchs essentially are. Smaller sharks and rays practice oviparity (egg-laying)> She cut open an obviously dead one, and there was albumen-y stuff  with little mushy things that looked like they had yolks inside.  Was it a Manta Ray? <likely a smaller skate or stingray... the egg capsules are rather common certain times of the year. Fascinating reproductive strategy. Tell her to dry out the egg case and make a bizarre amulet out of it <G>> Thanks! Lanita <best regards, Anthony>

Stingray babies Hi Mr. Fenner....... Just a few lines to let you know that work on the public aquarium here in Mauritius is progressing and we hope to open early in the new year. We have started to collect some specimens which are currently in quarantine. We were pleasantly surprised this morning to find that our stingray ( Torpedo sinuspersici ) had given birth to 6 baby rays of about 3 inches in length. <Neat> The baby rays have been separated from the mother ( she has not eaten for about 3 weeks)...... What should we feed the baby rays on......... Are there any special needs for the rays ( mother and babies) in general? Thanks for all your help and advice. Michael. <Do wait a few days... make sure any "yolk sac" food is absorbed before trying mouth-size (or smaller) chunks of meaty foods (shrimps, scallops, fish...) placed down near the young. Bob Fenner>

Big Skate Egg Cases Hi, I recently set up my 125 gal. cold water aquarium. <cool, hoping to set up my own in the next few months> Exactly one day after installing the chiller I found three Raja binoculata egg cases on the beach (I live on the northern Oregon coast).  I have found these in the past and have cut them open to determine if the embryos are alive. <why not just place the capsules back into sandy/muddy substrate where the female had deposited in the first place?> All but one of the embryos were intact and all seem to be doing well now.  I have placed the egg cases in an inverted position because I made the cut on the bottom. Do you think this will have an impact on their development? <Most likely yes, the "Cases" are actually Egg Capsules, which typically hold 3-4 eggs in there.  This is there to protect the developing skate not only from predators, but from other harmful parasites and free floating micro fauna that could attack them. It takes about 9 full months after being released from the female for the capsules to release the hatchlings. This fish evolved to have this protective capsule for a reason. If you are asking if the inverted position will have an impact.. an inverted position won't have much of an impact on an intact egg capsule if it is suspended and allowed clean water to give the eggs the oxygen they need. > Do you think hermit crabs will be tempted to crawl into the cases? <doesn't take much for hermits or any other of the clean-up crew to want to do something like that.  all it needs is to smell tasty, and developing eggs most assuredly have the "come and eat me" smell for a hermit.  I'm still not sure why you would want these eggs in your tank.  Aptly named the "big" skate, this species will grow, in about 5 years time, larger than 6 feet in length and weigh 200 pounds.  One of those fish best left were it is found.> Thanks, Cheryl <good luck with the 125 coldwater tank. -Magnus>
Big Skate Egg Cases, Follow-up Magnus, thanks for the help.  In the past I have only rarely found the embryos still intact and alive after the egg case has been washed ashore. Most definitely I would return the egg cases to the ocean if possible. Getting out beyond the surf at this time of year is very difficult, and I don't have a boat at the present.  They would just get washed up again onto the beach without being able to tuck them somewhere safe in deeper water. <I understand, sorry if I came across a bit harsh on the subject.  I had just been in a rather lengthy discussion with a young man about why he shouldn't just keep taking animals out of the wild and placing them in his tanks.  No use putting yourself in harms way to place the eggs back at sea.  Especially with the way Oregon's coast can be this time of year.> I plan to return the skates to the wild if I am successful in keeping them alive for the 8 months or so they have to go.  I do not see this as taking a living marine creature from the wild, but rather saving the eggs that would have perished on the beach, with the intention of raising them in captivity and releasing them after they have left the capsule. <I'm all for helping animals, I've raised a few baby birds, and random critters to health before releasing them.  Just be careful of what your local laws say on this matter.  Here in NY there are very strict rules on local fish being in your home aquarium.  Hate to see you get into trouble (and possibly heavy fines) for having a caring heart.  If you do manage to have the skates survive and hatch out be sure to record what you did, and other information for possible use later one.  I realize Skates are found up and down the northern pacific shorelines, but it never hurts to have more info on species now a days. Good Luck. -Magnus>

Sharks and Rays in Aquariums Gaining an understanding of how to keep these fishes in captive saltwater systems    New Print and eBook on Amazon   by Robert (Bob) Fenner