Cristian Poulson created the first resort on Heron Island in
the 1930s. Poulson was a fisherman and ran a turtle soup cannery on the island
in the 1920s. Turtle harvesting and processing was seasonal work and, as the
turtle population declined, Poulson made more money taking tourists to the
island in the off season. In 1930, he took over a failed effort to establish a
resort on Heron Island. In 1932 he opened his resort in the converted turtle
factory. It took visitors 6-8 hours to reach the island in sail-powered motor
launches; there was no harbor and passengers were ferried ashore across the
reef flat in small boats. Researchers and educators used the resort in the
1930s and the island was declared a national park in 1943. In the 1940s,
glass-bottom boats towed by motor boats allowed visitors to view the coral
reef. Passengers huddled under a blanket to view the reef through a glass
panel.
 |
| Catch of the day from the 1960s (link) |
|
|
Catalina flying boat that flew for Barrier Reef Airlines in 1947 (link) (State Library of Queensland)
|
In 1945, Poulson had the HMAS
Protector towed to Heron Island, scuttled her on the reef and then blasted
a hole in the reef that allowed small boats to reach the shore on low tides.
After WWII, Poulson began roundtrip air service from Brisbane after he cobbled
together one 28-passenger Catalina seaplane from three surplus planes that he
bought from the Royal Australian Air Force; the flight took two hours. In
November 1947 after visiting friends on a yacht anchored off Heron Island,
Poulson rowed ashore about 11:00 PM and was never heard from again; his skiff
was found south of Gladstone, but his body was never recovered. Today, about
30,000 people visit Heron Island each year, including tourists, researchers and
students (link, link).
 |
| Heron Island harbor |
 |
| Intertidal reef walkers at low tide |
The staff of Delaware North offer interpretive walks around
the island and to the Heron Island Research Station during the day, and reef
walks in the lagoon at low tide. Rande and I took the tour of the Heron Island
Research Station, which is operated by The University of Queensland (link). Established in 1951, it was the first marine research station on the Great
Barrier Reef; it burned down in 2007 and has since been rebuilt to host up to
150 researchers. We learned about research projects at the lab, including studies
of the epaulette shark, the most studied shark on the reef, which lives on reef
flats and can be stranded in tidepools at low tide. They withstand high water temperatures
and low oxygen concentrations for several hours by slowing their heart and
ventilation rates, and by sending more blood to the heart and brain (link).
Heron Island has 60% of the fish species and 72% of the coral species found
throughout the Great Barrier Reef.
 |
| Touch tank at the Heron Island Research Station |
We saw a climate change experiment in progress using
mesocosms to evaluate the impacts of climate change on the Great Barrier Reef.
Over the last century, the ocean environment has changed significantly.
Unusually high sea temperatures on the reef have triggered mass coral bleaching
and mortality events since the 1980s. Climate change is predicted to further
increase sea temperatures and acidification with or without reductions in
carbon dioxide emissions. The mesocosms experiments at the Heron Island
Research Station suggest that coral reefs have not been able to keep pace with
relatively mild environmental changes of the last century, and that the reefs
are unlikely to adapt to further increases in temperatures and acidification.
 |
| Climate change mesocosm experiment at the Heron Island Research Station |
Scientists at the Heron Research Station established 300-liter
(80-gallon) mesocosms with “nearly identical” patch reefs of sediments, live
rock, hard and soft corals, algae and fish. They ran three replicates of each
of four scenarios that manipulated carbon dioxide and temperature: present day
(control), pre-industrial, reduced emissions and business as usual (no control
on emissions) [technical details at the end this post]. They acclimated the
mesocosms for 2.5 months and ran the experiments during the austral summer (Nov
2011 – Feb 2012). Coral growth (calcification rates) was greatest under
pre-industrial conditions, followed by present day conditions; growth was
reduced, but still positive, under reduced emissions; growth under business as
usual was consistently negative. The results suggest that under business as
usual, coral reefs of the future “…will bear little resemblance to the
coral-dominated reefs of today.” Results from the pre-industrial scenario –
higher coral growth and reduced bleaching and mortality – suggest that “…key Heron
Reef assemblages…are better suited to conditions that occurred in the past than
to those of the present day” (link).
 |
| Healthy staghorn coral |
I had seen several news reports about coral bleaching on the
Great Barrier Reef in the months before we left; they referred to it as “…the worst, mass bleaching event in its
history…” (link).
Bleaching occurs when corals are stressed by increases in seawater temperatures.
They can cope with heat stress for short periods, but if the stress lasts too
long, they expel their microscopic algae (zooxanthellae), which provides them
food and gives them color, and their white skeleton shows through their transparent
tissues. If the stress is protracted, the corals starve and eventually die (link).
From February through April 2016, the
Great Barrier Reef had the highest average sea surface temperature since recordkeeping
began in 1900. I saw very little coral bleaching on my dives at Heron
Island, which was consistent with the Great Barrier Reef Marine Park Authority’s monitoring report
in June 2016 that no mortality from coral bleaching was seen in the Mackay–Capricorn Management Area. Eighty-five
percent of the mortality observed was in the northernmost 600 km (mi) of
the reef (link).
 |
| The Gantry at low tide |
Rande and I snorkeled at The Gantry on several high tides
and it didn’t disappoint. We saw green sea turtles and whitetip and blacktip
reef sharks among the patch reefs in the lagoon. Whitetips are skinny compared
to blacktips, which, according to one of the dive staff, are “proper sharks” because
they have the look and speed of larger, predatory sharks. A blacktip sporting
two remoras on its belly let me get close enough to take photos and video. One
afternoon I left The Gantry and swam to the pier into a current strong enough
to suspend sand particles and reduce the visibility. A 2-m (6 ft) lemon shark passed
me swimming with the current. I turned, followed it and managed to get a couple
pictures before it disappeared in the gloom.
 |
| Blacktip reef shark (Carcharhinidae) |
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| Lemon shark (Carcharhinidae) |
Heron Island is a major nesting site for green sea turtles;
we always saw them swimming in the lagoon, including six on one dive. We
watched while one turtle tore mouthfuls of algae from the patch reefs. Rasmus Fiedler, a snorkeler from Germany, was photographing turtles nearby and took a picture of
me doing the same. The largest turtle I saw was at The Gantry; it was a
green turtle about 2 m (6 ft) long weighing probably 100 kg (over 200 lbs). It swam
with long, deep strokes from patch reef to patch reef looking for something to
eat. It took one bite while I followed. It had a metal tag on the front left
flipper, probably a female that was tagged when she came ashore to lay eggs. In
the 1940s, turtle “racing” was popular among the guests at Heron Island. Staff
would flip female turtles over after they laid their eggs at night and guests
would ride them down to the water the next morning. Turtle riding was
prohibited in the 1960s (sign in the Visitor Center).
 |
| Green sea turtle |
 |
| Photo by Rasmus Fiedler of turtles and me |
Rande was cold after an hour and swam back to shore. I
stayed in the water and swam out to the reef flat where the corals were contiguous as far as I could see. Juvenile
fishes of many species feed on plankton in the water above the corals; when
threatened, the cloud of brightly colored fishes disappears into the corals for
protection. I passed several mixed-species groups foraging on the reef –
including parrot fishes, surgeon fishes and butterfly fishes. Smaller groups sometimes
coalesced into groups of 50-75 that foraged together for a while. Closer to the
edge of the reef, I encountered large unicorn fishes swimming in loose, polarized
schools and then diving to the bottom in unison to feed. The mixed groups of
parrotfish inshore were more compact while the unicorn fish were more spread
out. The two groups didn’t mingle, but they foraged in contiguous areas. I was on
top of the reef about far from shore when my camera turned itself off flashing “battery
exhausted” (I usually took 150-200 photos on one battery charge).
 |
| School of small parrotfishes (mostly) foraging on the reef flat |
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| Bluespine unicornfish (Acanthuridae) |
I had to cross the shallow sand flats in the lagoon on my
way to and from the reef flat, and I often circled the sand looking for skates
and rays. I was struck, by the number of fishes swimming over, or sitting on,
the sand. They were silvery-white and blended into the white sand background appearing
and disappearing like ghosts. Interestingly, the sand is produced over
millennia by parrotfishes and their relatives grazing on corals, digesting the
organic matter and excreting bits of coral skeletons that become sand – picture
that the next time you’re on a tropical island lying on a white sand beach in
what amounts to just so much fish poop.
 |
| Sea mullet (Mugilidae) |
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| Northern whiting (Sillaginidae) |
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| Blacktail grubfish (Pinguipedidae) |
One afternoon Rande and I walked around the island, which
can be done in about an hour – Heron Island is 800 m long and 300 m wide. I
stopped to take pictures at Shark Bay while Rande chatted with an older couple
from a small town near the Murray River in southeastern Australia. The woman
did all the talking – “I’m the talker in the family; my husband is a farmer and
doesn’t talk much.” They have a 4,000-hectare (10,000-acre) farm and raise
merino sheep, goats and several crops. Stately and well-educated, she wore her
long graying hair in a French twist. She asked us where we were from and where
we were going. She didn’t want to offend us, but she wanted to talk about
Donald Trump. She was “aghast” that the U.S. could nominate, let alone elect, him
for president. The couple had traveled widely, most recently in Thailand and
Vietnam. She said that one of her pleasures in traveling was meeting people
from other countries and asked us how we found Australians (friendly and
helpful). They were leaving the next day and wished us safe travels.
 |
| Shark Bay |
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| Pied oystercatchers |
I made several dives on the southwest side of Heron Island. We
had a strong current from top to bottom at a coral wall called Ledges that made
photography difficult – by the time I saw the picture I wanted, the current had
carried me beyond it and I had to circle back into the current wasting time and
air. The dive at Gorgonia started where the first dive ended. The current had
slackened because we were closer to high tide. We descended to the bottom and entered
the reef at 17 m (55 ft) through a crevasse that opened into a small canyon crowded
with bommies creating a maze-like dive.
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| Heron Island bommie |
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| Sea fans (gorgonians) and green turtle weed (alga) |
The leader knew the route and the rest of us followed single file. We saw a green sea turtle sleeping on top of a bommie. Leaving the maze, we continued along the wall of corals. I saw a white line jutting from the base of the reef wall that looked too straight to be natural, but it turned out to be one antenna of the painted rock lobster.
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| Green sea turtle sleeping on a bommie |
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| Painted rock lobster |
The coral-eating
crown-of-thorns starfish is a major cause of coral mortality on the Great Barrier Reef.
Outbreaks begin in recurrent waves that migrate from north to south over more
than a decade. Historically, outbreaks occurred in 50-80 year cycles; in the
last 50 years there have been three outbreaks. Interestingly, starfish
outbreaks on mid-shelf reefs open to fishing were almost four times higher than
in no-take zones. Coral cover was also greater after outbreaks in no-take
zones. Reserves are a management strategy that benefits reef biodiversity and
tourism. While the effects are clear, the ecological mechanism responsible for
this pattern is uncertain (link, link).
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| Crown-of-thorns starfish |
On Thursdays, the barge Curtis
Endeavor, a roll-on, roll-off ship from Gladstone, calls at Heron Island to
resupply the resort and the research station. It brings empty trash bins, tanks
of propane and large plastic carboys of gasoline, supplies for the resort’s
kitchen and gift shop and kegs of beer for the bar. It carries away full
trashcans, empty propane tanks and gasoline carboys. While all this is
happening, it pumps 15,000 liters of diesel fuel to the maintenance yard for
the three generators that power the resort and research station. The island has
some solar panels, but the birds roost (and poop) on the panels limiting their
effectiveness. The island
has no fresh water supply. A small desalination plant on the island uses
reverse osmosis to produce water for human consumption.
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| Curtis Endeavor unloading supplies at Heron Island |
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| Supplies unloaded from the Curtis Endeavor |
Occasionally, a seaplane from the mainland delivers visitors
to Heron Island. The plane, a beautiful white de Havilland Beaver buzzed the shallow water inside the reef looking for and alerting snorkelers,
landed and taxied to the beach. Three people were on the beach to meet the
plane. One man waded into the water and turned the plane around. Three people climbed
down from the cabin onto a pontoon and waded ashore. A porter carried their
luggage. It was all very efficient, if makeshift – it took 20 minutes from the
time the plane touched down until it lifted off. The fare for a one-way flight to
Heron from the mainland is about $400 AUS.
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| Seaplane unloading guests and their luggage at Heron Island |
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| Seaplane leaving Heron Island |
I made two dives the day before we left Heron Island. The
first dive was at a place called Junction where several currents meet. I was
the only diver and Josh, my guide, let me lead at my own pace; it was the
fishiest place in (numbers of species and individuals) that I dove. We were
down 55 min at 10-15 m (33-49 ft). The reef wall was incised with small canyons;
I swam into the larger ones. We saw green sea turtles and whitetip reef sharks
– I had seen so many turtles that I didn’t take any pictures. The second dive
was at Heron Bommie (40 mins at 16 m, 53 ft). I dove with Josh and a
father-daughter pair from England. I got separated from the group following a large,
silvery Spanish mackerel into deeper water. I didn’t see any bubbles when I
returned to the bommie. I looked around for a minute and then swam with the
current. When I didn’t catch them, I figured they circled the bommie a second
time; so I back-tracked slowly taking pictures. They caught up to me a couple
minutes later. Back on the boat, Josh said: “I thought we lost you.” Good thing
they didn’t, but it was my last dive and they couldn’t ban me from diving.
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| Long black sea cucumber |
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| Leopard sea cucumber and blue linckia sea star |
After diving and snorkeling Heron Island for a week, I came
to the conclusion that, after fishes, holothurians rule! Never have I seen so
many sea cucumbers – giants and dwarfs; smooth and warty; brightly colored and
drab. Sea cucumbers are echinoderms, like starfish, without obvious external five-part radial symmetry, but they have five radii running from the mouth to the anus to which their tube feet are attached. They have a head with a mouth, a tube-like digestive tract and
an anus. Most sea cucumbers consume large quantities
of sand and silt, which have a rich organic coating, and leave a characteristic
trail behind. Their tube feet adapted to crawling over the seabed, and
feeding tentacles (specialized tube feet) around the mouth collect sand
particles and pass them to the mouth. Interestingly, sea cucumbers host a
variety of symbiotic crabs, shrimp and worms in their gut. Pearlfishes
(Carapidae) live in starfishes, pearl-oysters and sea cucumbers, including the
prickly and spiny black, which are found at Heron Island.
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| Bulk carriers anchored off Gladstone |
Nearing Gladstone we passed a dozen empty bulk transports
anchored a couple miles outside the harbor. They were waiting to load bulk
minerals: aluminum ore (red), white and brown, and coal; all piled high
alongside where the ships tie up. We passed a bulk carrier coming into the
harbor. Two bright blue tugs were waiting for it; one was performing pirouettes
on its axis (you can see the circle of calm water). Maybe the skipper was
bored, or maybe he was showing off; in either case it was an impressive display
of maneuverability. There are 12 ports in or adjacent to the Great Barrier Reef
and their imports and exports are increasing. There were more than 9,600 ship
voyages through the region in 2012-2013 and that number is forecast to increase
by 2.5 times over the next 20 years. Ship groundings are uncommon (0-1 per
year), but their grounding sites can take decades to recover (link).
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| Empty bulk carrier W-Smash coming into port |
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| Tug waiting for the W-Smash |
We tied up at the dock in Gladstone, got off the Heron Islander, retrieved our luggage
and car, and left for Yeppoon, a town on the Coral Sea 160 km (100 mi) to the
north.
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| Gladstone harbor |
Health and management of the Great Barrier Reef
The Great Barrier Reef Marine Park is managed by a cross-jurisdictional
partnership between Australia’s national government and the state of Queensland’s government. “The [park] is managed to
allow a diverse range of activities, such as fishing and collecting, as well as
to protect the reef’s natural and cultural values.” The park was rezoned in
2003 “to better balance human use and conservation” to better protect natural
and cultural resources (sign in the visitor center). Thirty-three percent of
the Great Barrier Reef Marine Park has marine national park status (green zones
where fishing and collecting are not permitted) and less than one percent has
scientific research status (research zones, many with permanent research sites).
Co-management with Australia’s indigenous traditional owner groups, who harvest
turtles and dugongs, is “developing.” Impacts within the jurisdiction of the
Marine Park Authority are fisheries, tourism and shipping. Fisheries are
managed by Queensland via fisheries management plans. The Marine Park
Authority’s jurisdiction does not include the impacts of terrestrial runoff or
coastal development on water quality. Coastal habitats (freshwater wetlands,
saltmarshes, mangroves and seagrass meadows) are important in the life cycle of
some marine species; they also slow runoff from storms reducing that amount of sediments
and nutrients that reach the ocean (link).
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| Redthroat emperor (Lethrinidae) |
Questions about the health of the Great Barrier Reef have
appeared in news reports for several years. In 2003, the Australian and
Queensland governments adopted the Reef Water Quality Protection Plan to
reverse the declining quality of water entering the reef; it was updated in
2009. In 2012, UNESCO’s World Heritage Committee announced that it was
considering adding the Great Barrier Reef to the “in danger” list of World
Heritage Sites. At the request of the committee, the Australian government
commissioned an assessment to identify and manage risks to the Great Barrier
Reef, which was published in 2014. Threats include climate change (increasing
water temperatures and ocean acidification), declining water quality from
coastal development (dredge material disposal) and agricultural practices
(sediment and nutrient runoff), fishing (over-fishing, illegal fishing and
bycatch) and extreme weather (flooding and cyclones) (link).
 |
| Redtooth triggerfish (Balistidae) |
The joint Australian and Queensland governments’ 2014 Outlook
Report found that despite increasing adoption of best management practices for nutrients
and pesticides by sugar cane and crop farmers, and reduced erosion from cattle
grazing, the condition of inshore coral reefs and seagrass beds remained poor. Climate
change was identified as the most serious threat to the Great Barrier Reef. Seawater
temperatures are rising and the trend is expected to continue, increasing the
risk of mass coral bleaching. Gradual ocean acidification will reduce the
growth and survival of corals. More frequent intense weather events will
cause more damage to the reefs and give them less time to recover. Since
monitoring began in 1986, hard coral cover has declined from 28% to 14% and the
rate of decline has increased in recent years. An independent group of
scientists concluded that “…the overall outlook for the Great Barrier Reef is
poor, has worsened since 2009 and is expected to further deteriorate in the future.
Greater reductions of all threats at all levels, Reef-wide, regional and local,
are required to prevent the projected declines in the Great Barrier Reef and to
improve its capacity to recover” (link). Only five percent of the area of the Great
Barrier Reef Marine Park is coral reefs; the remaining ninety-five percent is non-reef habitats that are extraordinarily diverse, but less well studied (link).
 |
| Barrier Reef anemonefish (Pomacentridae) |
The economic value of a healthy Great Barrier Reef is $5.5
billion AUS annually, including 54,000 full-time jobs, and increasing. Tourism
is the main source of reef-based income and employment [1.9 million visitor
days in 2013 (link)];
it is 36 times greater than commercial fishing and increasing. The economic
value of recreational use (mostly fishing) is slightly more than commercial
fishing. Notably, Australia’s expenditures on management of the Great Barrier
Reef Marine Park, including zoning compliance, are less than one percent of the
annual economic value and decreasing. Recognizing that an “in danger”
determination would be disastrous for tourism, the Australian government implemented
additional plans to reduce land-based and fishery impacts to the Great Barrier
Reef. They also lobbied the World Heritage Committee nations against an “in
danger” designation. In 2015, UNESCO decided not to list the Great Barrier Reef
as “in danger” noting the progress that Australia had made in coastal
development and water quality, but said it would revisit the issue in 2017 (link, link).
 |
| Heron Island sunrise |
Heron Island
mesocosms experiments: the partial pressure of carbon dioxide (pCO2) in the
pre-industrial atmosphere was about 280 µatm; today it is about 370 µatm. The pCO2
in seawater varies geographically and seasonally from about 150 μatm to 750
μatm because of differences in biology, temperature and
ocean circulation; the average pCO2 in seawater is about 7 μatm lower than the atmosphere. When seawater pCO2 is less than
the atmosphere, the sea takes up CO2 and when it is more, it releases CO2 (link). In the Heron Island experiments, the present day (control) scenario used ambient
seawater (they didn’t report the pCO2). The pre-industrial treatment lowered the pCO2 and temperature (-104 µatm CO2, -1°C) of seawater. The reduced emissions treatment
raised pCO2 and temperature (+172 µatm CO2, +2°C) and so did the business as
usual (no control on emissions) treatment (+572 µatm CO2, +4°C) (link).
Fish identifications based on: Allen, G.R. 2009. Field Guide to Marine Fishes of Tropical Australia and Southeast Asia. Western Australia Museum, 4th ed. 287 pp.
Echinoderm identifications based on: Allen,
G.R. & R. Steene. 1994. Indo-Pacific Coral Reef Field Guide.
Singapore: Tropical Reef Research, 378 pp.
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