{"id":4937,"date":"2013-11-05T13:11:31","date_gmt":"2013-11-05T13:11:31","guid":{"rendered":"http:\/\/bvblog.wpengine.com\/?p=4937"},"modified":"2014-04-25T12:36:54","modified_gmt":"2014-04-25T11:36:54","slug":"coral-spawning-madagascar-search-elusive-mass-spawning-event","status":"publish","type":"post","link":"https:\/\/blog.blueventures.org\/en\/coral-spawning-madagascar-search-elusive-mass-spawning-event\/","title":{"rendered":"In search of the elusive event: coral spawning in Madagascar"},"content":{"rendered":"

By Erika Gress, Field Scientist, Madagascar<\/em><\/p>\n

One of nature\u2019s most unusual, mysterious and least witnessed events happens in the ocean; coral spawning. Despite years of data collection and night snorkelling trips, for the BV Madagascar team, this rare sight has proven to be elusive.<\/p>\n

For coral reefs and me it was love at first sight, so I didn\u2019t think twice about trading a few nights of sleep for the chance of witnessing such a rare and magical event.<\/p>\n

\"coral

Watching and waiting for the corals to spawn<\/p><\/div>\n

But how do we know when to anticipate the corals in Andavadoaka to spawn? Previous field scientists began researching the phenomenon in 2008 and more work was done in 2012. Spawning was documented (28-29 November 2008 and 5-6 October 2012) but sadly not witnessed due to unfavourable weather conditions. We used their research as a starting point, along with a number of published studies, and direct reproductive condition assessment of Acropora<\/em> colonies when we were diving. From this we set out a predicted timetable of potential spawning events. In mid-August, 19 colonies of Acropora<\/em> were tagged in one of the dive sites we survey regularly with the help of a team of our volunteers<\/a>.<\/p>\n

\"coral

The tiny coral eggs<\/p><\/div>\n

Acropora<\/em> is one of the only two genera in which eggs are visible to the naked eye, and in most cases the presence of gametes, their colour and size gives you an idea of their maturity and thus how close they are to spawning .<\/p>\n

After following the maturation process of the eggs, studying information from other locations where more data about spawning events is available, and taking into consideration a number of local conditions such as tides, the phase of the moon, night and day length, water temperature, etc. we began nightly snorkelling trips on the 9th of September.<\/p>\n

\"coral

Erika with the important collected samples<\/p><\/div>\n

Sampling on a nightly basis not only increases your chances of observing a spawning event but also, through observing a sudden absence of eggs, can indicate the night of spawning in the unfortunate event that we missed it. Studies suggest most species spawn between dusk and midnight, so we dutifully arrived at our tagged colonies just before 9pm and split into buddy pairs to duck dive and observe the corals. I happily volunteered to jump in first, accompanied by Patty, a local fisher who\u2019s been assisting our research over the past year. We jokingly informed our Dive Managers, Bill Thomson and Lisa Crews, who were waiting on the boat, that the code for spawning would be \u2018It\u2019s happeninggggggg!!\u2019. In truth we had very little anticipation that we would actually get lucky on our first attempt.<\/p>\n