Thursday, May 29, 2014

grunion greeting, 2014 #3

prejuvenile spotted cusk-eel

While we were out on the nighttime beach looking for grunion, it quickly became all about the cusk-eel for J and me.  Armed with a flashlight under the complete darkness of the clear skies and new moon, we eventually found 4 or 5 after waves washed out (we had different counts, and we didn't even need a 2nd hand to count - ha!).  They seemed a bit lethargic, kind of like the grunion I observed on May 15 (Something weird is going on, because even in SoCal the grunion are inexplicably beaching themselves and not in a good way.)  One cusk-eel we found wiggled its entire body down, tail first, not too dissimilar to what a grunion does when she lays eggs, except the cusk-eel completely disappeared into the sand.  We also noticed numerous mini-craters that noisily bubbled water as the waves receded.  J kept saying, "It totally sounds like a spa!"  Ya, the waves were relatively calm this night for us to hear the bubbling.  We're wondering if all the cratered holes were created by the freshly dug cusk-eels?  There were also a handful of cancer crabs and sand crabs digging down in the sand, but nothing thin enough to make a drill-like hole.

It's thanks to Dr. Guacamole (that's not his real name, btw) for alerting me to the fact my crappy photo "eel" from July 9, 2013 was a cusk-eel, but all I could recall to tell J this night was that it wasn't a real eel and was actually a fish.  Dr. Martin also chimed in and eventually I was able to get "retired" CDFW Bob Lea's expert ID down to species.  He cowrote the technical report Checklist of Fishes Known to Occur in Monterey Bay National Marine Sanctuary with Erica Burton last year.  And thankfully, considering I'm bugging some very busy people with my ID questions, they were glad to get my observations and photos.  I'm guessing not a lot of people report cusk-eel sightings.  This is only the second time I've ever seen them in all my grunion nights.  I've seen grunion more times than cusk-eels, and that might be saying something. 

I found the burrowing tail first to be fascinating, especially in the exact same spot we've seen the grunion lay eggs.  What makes this beach so great for these sand-loving fish?  The extremely calm waters and fine sand?  With Bob's permission, this is what he said about my photo above, "The cusk-eel is a prejuvenile Spotted Cusk-eel, Chilara taylori.  At this size the spots have not yet developed; I am guessing the fish in photo is ca. 5 to 6 inches in length.  Cusk-eels enter the substrate tail first and their caudal structure is modified, fusion of bony elements, enabling them to do this.  There have been several papers discussing tail-standing and burrowing in cusk-eels and I can send you the references if you are interested.  Chilara taylori was originally described from the beach at Monterey in 1858.  We encountered prejuvenile fish last year (July or August) solving a puzzle that I did not know the answer to until then.  Also, the prejuvenile stage is nektonic and the fish you saw are in the transition process of changing from a pelagic to benthic existence.  Good to get your observation."  Man, it's been forever since I've seen someone use "ca." - no offense to Bob.  Fortunately, after having watched Bob measure grunion last year, I thought to throw down my lined-note pad next to the cusk-eel for a photo and then later the lined-note pad with a ruler to get an accurate read of size (I don't take my favorite ruler out for fear of losing it in the waves).  So, I sent a second set of photos.  The one shown above is only ~3 3/4" long, which turns out to be in the typical 70 to 100mm range.  Bob collected 20 specimens last year, and they're now housed at CalAcademy (CAS 236552).  I wonder how long they live?  Holes and infrequent sightings make me think of periodical cicadas which develop en masse every 13 or 17 years.

I should mention that I had a very difficult time finding an ID match online a couple weeks back when I was updating my July 9, 2013 post, but that's not surprising for marine life.  Little did I know the cusk-eels I've seen aren't the fully spotted adults yet.  Ha!  There are several SCUBA divers' community groups that share wonderful photos of marine animals.  Makes me wonder if any of them have ever seen grunion, because so little is known about their behavior off the sand and in the water.



I'm always entertained by Charlie.  Over the course of half an hour 3 Charlies showed up and were unusually friendly with us as we stood at the water line with them.  I think they snatched up a couple tiny cusk-eels.

(CDFW)

Eh, we only saw 2 waves of 6 grunion each (whippee) not too far from the cement structure down the beach.  I reported it as a W-1, because Dr. Martin instructed me that any sighting at all is significant for the Monterey Bay.  It was a mellow night, good to be out with J, and always fun to find new things.  Oh!  We also quickly stopped at San Carlos Beach on our way home.  No grunion there.

05/28/14 full moon 11:43am
05/29/14 high tide 11:18pm 5.52 ft
beaches: Municipal, San Carlos
Charlies: 3 + 3 western gulls
others: J, Steve the Fisherman (yes, he was there - I should recruit him!)
my observation time: 10:27pm - 12:10pm
W-1, 2 sets of 6 (same individuals?) near cement structure down beach 11:33-11:38pm.

5 comments:

Jennifer said...

It's interesting to see how it varies in different years. I looked back to your may 26, 2013 post and was amazed at the huge amount of grunion that showed up. Wow!

Brent Morgan said...

How very cool to observe a seeming rarity like the cusk eel. Congrats!

Katie (Nature ID) said...

Jennifer, I've really enjoyed seeing the variations of the nighttime beach at regular intervals, with or without grunion.

Thanks, Brent. Cusk-eels are probably not all that rare (I actually don't know), but catching them in this transition stage might be very hard to find.

Keith E said...

why do the cusk eels come on shore?

Katie (Nature ID) said...

Keith, re-read Bob's quote in this blog post, again. Contact him if you want more information. Most likely, this shore stage is not well understood by anyone.