Ew! There’s Sperm on my Shoe!!!

16 11 2012

Recap: I now have 14 red abalone adjusting to life in Seattle in the basement at UW (unfortunately, two didn’t survive the adjustment – Seattlites have to be a little tougher than those Californians!).  Once they are comfortable with their new home, I’m going to practice spawning them so I’m able to use live gametes in my field experiments.  But before I can spawn them, I need to learn how. 

Pinto abalone sperm under 80x magnification (B. Blaud)

Apparently there’s more to spawning abalone than putting on soft music and chilling a bottle of Riesling in front of a romantic fireplace.  Although their tastes are a little different from ours on what gets them in the mood to make babies, they are still very particular and can be temperamental.

 

I was invited to participate in spawning pinto abalone up at the hatchery at the NOAA Research Facility in Mukilteo, located 20 miles north of Seattle.  Pinto abalone are declining at a rapid rate in Washington, and are functionally extinct in Puget Sound.  In efforts to reinstate this amazing species, ongoing restoration projects focus on spawning, raising, and outplanting young abalone, and monitoring sites for population growth and recruitment.

 

Pinto abalone (J. Bouma)

     Some basic facts about pinto abalone:

Range from Sitka, Alaska to California

Are relatively small (4 to 6 inches)

Live in waters up to 35 feet deep (10m)

Spawn between May and October.

 

I mentioned before that it can be rather difficult to get abalone to spawn, but I didn’t mention how hard.  It is a little easier to get males to spawn (big surprise there), so a lot of focus goes towards getting the females ready.  Although the typical spawning season is between May and October and it’s already November, the pinto in the hatchery hadn’t spawned yet.  Researchers have been trying for months with no success, so no one anticipated big results on this spawning attempt either, but it’s worth a try.

 

Set up for spawning pinto abalone (B. Blaud)

Several methods are used to set the mood and induce spawning, which affect each species differently and vary in success.  Temperature increases and exposing abalone to air naturally stress the animals, making them more inclined to spawn, but curiously, the exposure to UV-light irradiated water and diluted hydrogen also induce spawning.  For successful fertilization, one of the key requirements is synchronicity in spawning, where eggs and sperm must be released in the same location and same time.  To cue neighboring abalone that someone is spawning, a chemical called prostaglandin, aptly named after the location of its discovery – in the human prostate, is released into the external environment whenever an abalone spawns.  Both the UV-irradiated water and hydrogen peroxide stimulate the production and release of prostaglandin, which in turn excites abalone, effectively setting the mood and getting them to spawn.  It’s not really my preferred romantic setting.  I prefer more wine and a little less hydrogen peroxide, myself.

 

For spawning pinto abalone, we used a combination of stimulants: we increased the temperature of their water by 3 degrees Celsius and added diluted hydrogen peroxide to their water.  Ideally, we let them sit in the water for 3 hours and when they are put into clean seawater, they spawn shortly after.  During those 3 hours, we check periodically for early spawners and get them into clean water ASAP if they start spawning – hydrogen peroxide damages the eggs and sperm.

 

Spawned female pinto abalone (B. Blaud)

Until spawning begins, it’s a waiting game and a good time to get coffee and hang out.  Once spawning begins, things get busy!  All the abalone have their own buckets to spawn in so all fertilization crosses can be controlled to preserve genetic diversity in later crosses.  Sperm is collected and examined under a microscope to measure sperm count.  Similarly, eggs are put in clean seawater and counted for density.  Overall, we had two males and four females spawn, producing over 3 million eggs.

 

When all counts are known, fancy arithmetic with large numbers is done to determine how much sperm is required to fertilize a bucket full of eggs.  The desired concentration is approximately 500 sperm to each egg.  Surprisingly, this included adding less than 10mL of sperm to a bucket containing ~500,000 eggs.  After letting them marinate for 15 minutes, the eggs are washed and put into a tank where they will develop for 12 to 24 hours before hatching.

 

And that is the miracle leading to abalone babies!!!

 

Morse, D.E., H. Duncan, N. Hooker, and A. Morse.  1977.  Hydrogen peroxide induces spawning in mollusks, with activation of prostaglandin endoperoxide synthetase.  Science, 196(4287): 298-300

Advertisements

Actions

Information

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




%d bloggers like this: