Cued by a temperature change?

  

Eric was doing an end-of-day check on some tanks in the lab last night and noticed some sea urchins spawning!  Above, a male Purple Sea Urchin (Strongylocentrotus purpuratus) with clouds of sperm being released from the gonopores on the upper surface.  

Looking around, we eventually noticed a few female Purple Sea Urchins releasing eggs (more yellow-orange in color):

 

Our guess is that warmer ocean temperatures during the past couple of days triggered spawning.  There's been a lot of upwelling this year, with water temperatures as low as ~8.8°C (~47°F).  But winds calmed down at the end of the week and temperatures rose to ~12°C (~54°F).

There were also a couple of other echinoderms spawning.  Here's a male Red Sea Urchin (Mesocentrotus franciscanus) releasing sperm:

 

 

 

And a female Ochre Sea Star (Pisaster ochraceus) releasing eggs:

 

 

 

What's that saying, "Spring is in the water"?  ;)

So egg-citing!

  

So cool!  This is a female Ochre Sea Star (Pisaster ochraceus) spawning.

We had to work a little late tonight, but it paid off because just before we were getting ready to leave, Eric noticed that a few sea stars were spawning in one of the tanks at the lab!

It's possible they were triggered by the recent change in the weather.  When the NW winds are strong, seawater temperatures are usually cool; then when the winds calm down, seawater temperatures often rise.  Yesterday the seawater temperature was 9°C (48°F), but it increased to 13°C (55°F) today. 

Here's an even closer view where you can see a large number of eggs being released through pores in the surface of the sea star:

 

 

Some of the eggs gathered on a piece of kelp below:

 

 

 

 

We were curious about whether other animals might also be triggered to spawn, so we checked another nearby tank and...voilà!

 

 

 

This is a male Red Abalone (Haliotis rufescens) releasing sperm.  The raised pores in the shell act like little volcanoes when the abalone is spawning:

 

 

 

 

 

We don't get to see sea stars and abalone spawning that often, so it was a fun way to end the day!

 

Eggs in neon

  

After field work this morning, I noticed a couple of Giant Green Anemones (Anthopleura xanthogrammica) were spawning, so I took a couple of quick photos for the record.

Sometimes spawning is triggered by a large change in water temperature.  During the past week we saw extremely cold temperatures  of ~8.5°C (~47°F), and then when the winds dropped temperatures rose to ~12.5°C (~54.5°F). 

Here's a close-up of the eggs:

 

 

 

And a zoomed out view of the entire female anemone with the beige eggs accumulated on the lower edge of her oral disc:

 

 

 

 
There were a few males spawning, too:

 

 

 

P.S.  I haven't seen anemones spawning that often, but I wrote about another observation back in 2013.  See "Fortuitous" on 28 June 2013 and "Little narwhals" on 23 July 2013 (the latter includes photos of anemone larvae).