By all accounts, there aren’t ‘that’ many mermaids from Braintree, Massachusetts; a folksy, 40,000-strong municipality just south of Boston, on America’s mostly chilly east coast. In fact, when the winter temperatures regularly dip below freezing, most Bay Staters are sooner found skating atop the nearby lakes and ponds, rather than daydreaming about the depths below.
But the Reef Authority’s own (former) resident Bostonian, Dr Jess Stella, who grew up skiing the nearby slopes of New Hampshire and Vermont, seems to have broken the mould.
Today, as the Assistant Director of Reef Health Surveillance and Innovation based in tropical North Queensland – where summer temperatures rarely dip below 30 degrees Celsius - she readily admits she’ll take any opportunity for a deep dive below the surface.
“I first tried scuba diving many years ago when I was on holiday in the US Virgin Islands,” Jess recalls fondly.
“I just remember feeling completely at ease and thinking ‘this is my home environment’. I always wanted to be a mermaid as a kid and that was my opportunity! I was just really blown away by how different the environment is; you can move in a 3D manner and the animals want to interact with you, so I felt like I was just really part of the environment.”
And, with the warmer summer months now well and truly upon us, Jess says there is often no better time to don the goggles for a dive, specifically from October through to December, when the Reef literally explodes into life.
Some corals, known as brooding corals, reproduce by releasing fully developed coral larvae into the water, on a year-round basis.
But, for those lucky enough to witness it, mass or broadcast coral spawning is the greatest reproductive show on earth. It only happens once a year, after a full moon, and only when water temperatures can stimulate the maturation of reproductive cells within the adult corals.
“There’s no Tinder for corals,” Jess says with a laugh. “They can’t move around or go to bars and meet potential mates. So, a lot of species will reproduce through broadcast spawning, where millions of bundles of coral sperm and eggs, or gametes, are released into the water column.
“And it’s here that the real magic happens when these bundles of spectacular yellows, pinks, and oranges meet other sperm or eggs of the same species and fertilisation occurs to bring about new coral larvae.”
Corals rely on their chemosensory ability – similar to a sense of smell – which they use to detect their environment. They use it to determine which coral species are nearby and when spawning conditions are just right. Fun fact: The mood usually strikes two to six nights after a full moon, and always under the cover of darkness.
“It’s usually about four hours after sunset which keeps predation down as well because coral gametes are food for many species on the Reef including planktivorous fish and invertebrates,” Jess says.
“These species will eat every bit of plankton that comes on to a reef. Any little particle is up for grabs. So, essentially they spawn at night when the predators are sleeping.”
And rightfully so; coral larvae face often insurmountable odds, the least of which involves avoiding predators. If fertilisation is successful and the new coral survives a week or so floating along currents, it needs to find a suitable location on the ocean floor that is not only clear of algae and sediment, but also receives enough sunlight to nourish and help them grow into a mature coral. Thus, with so many obstacles to overcome, it’s no surprise that – on average – only one in a million will survive to maturity.
But they do, and have done, for millions of years!
Although it was only in the 1980’s that researchers from James Cook University documented this spectacular natural phenomenon, just off the coast of Magnetic Island.
“It’s one of those things where you have to be at the right place at the right time,” Jess says.
“The first time that I witnessed it was with a friend diving off Magnetic Island and we had the whole place to ourselves. It was very special.”
Herein, Jess says, lies the beauty of the Great Barrier Reef and the critical role that the Reef Authority plays as the lead management agency of Australia’s greatest natural wonder to help ensure it continues for future generations.
A large part of Jess and her Reef Health Surveillance and Innovation team’s responsibility involves monitoring the Reef for crucial signs that the Reef is healthy and regenerating, particularly as it faces growing pressure from human-driven climate change.
“I don't run around with a spy camera, so surveillance in the title is a bit misleading,” she says wryly. “Essentially what it means is surveying the Reef, often through aerial surveys or in-water surveys. What we do throughout the year, and especially leading into summer, is monitor environmental conditions. So, if there's any increase in sea surface temperatures for example, it might indicate a marine heatwave is happening and that could put corals and a lot of other marine life under stress.”
This includes monitoring the risk of more visible natural disasters, such as cyclones, which can also be more difficult to predict.
“If we have a La Niña year, which is often associated with heavier rainfall, we might have flood plumes that carry excess sediment and nutrients to the Reef and can smother coral and cause outbreaks of coral disease. So, it's looking at the likelihood of these events happening and then formulating a plan,” she says.
“Obviously we can't stop any of these natural disasters; we can't go out and protect a reef from a cyclone or stop bleaching once it happens. So that surveillance part comes in and we actually monitor the health of the reef to see how it fares through each of these events; whether it can withstand the impacts, and whether there are measures we can take to further build resilience.”
And on top of that list, not surprisingly, is addressing the threat of climate change.
“We at the Reef Authority can't limit emissions for the entire globe,” Jess says. “That is going to require a concerted global effort. One of things we can do is enforce our compliance on Marine Park Zoning Laws, making sure everyone is doing the right thing in the right areas when they are out enjoying the Reef.”
Zoning laws have proven to help the Reef build natural resilience which is pivotal to ensuring this cultural and ecological icon can be enjoyed sustainably for generations to come… especially when the lights go out!
“Coral spawning is the Reef literally regenerating before our eyes,” Jess says.
“I think everyone should have it on their bucket list because it really is just magical.”