Thursday, November 16, 2017

The Secret Lives of Coral Reef Fish

Anjani Ganase, marine biologist, looks into the world of coral reefs at some of the residents in these undersea cities. Down there, she says, it’s noisier than you think!

When we dive along coral reefs, we glimpse moments in the lives of the fish and marine creatures bustling about on their daily routines in underwater coral cities. At first glance, movements may appear arbitrary, but as you observe for a minute or two we start to recognise the activity the fish is carrying out, whether it is foraging or simply hiding out. However, for more rare activities or seasonal movements, such as at dawn or dusk or during mating season, this would require longer, more consistent times spent looking into the secret lives of fish. Here are a few observations of some reef fish behaviours:

Hunting buddies, the grouper and the moray eel

Grouper (Plectropomus pessuliferus) and Giant Moray Eel (Gymnothorax javanicus) make an excellent partnership for hunting on the coral reefs. How this partnership came about is not clear but it appears that the different strategies of the grouper and the moray eel compliment each other and therefore make for highly successful cooperative hunting of prey. Groupers tend to cruise over the coral reefs during the day, hunting fish that have strayed a bit too far off the reef. Moray eels are able to weave in between the reef framework, bombarding fish and backing them into tight corners. Morays also prefer to hunt at night, where low visibility gives them an advantage.

The grouper often initiates the hunting partnership, which is more likely to occur after an unsuccessful hunt when the grouper is hungry. The grouper will swim to a known resting spot of a moray eel, near to where it may have lost its prey. The grouper will then gesture to the eel in the form of a rapid shaking of the head in front of the eel’s face. The eel responds by swimming out on to the reef together with the grouper. If the uncaught prey is nearby, the grouper will then attempt to guide the eel to the location, usually a hole, where the prey previously escaped. The eel then uses its method of hunting. For the prey to escape the moray it may head to open water, where the grouper will be waiting. Alternatively, if the eel corners the prey, then the eel will have it for itself. Researchers have found that the grouper and moray eel could spend over half an hour hunting together, and both the grouper and the eel still benefitted overall from these arrangements, even though they did not share the meals (Bshary et al. 2006). On the occasions where the eel fed on the prey, the grouper did not appear to act aggressively towards the eel. Further research may be needed to determine whether the grouper will approach the same eel in the future. Groupers have also been observed gesturing for the aid of other predators. In an area of the reef where the prey is hiding, the grouper will remain near the opening and perform a headstand and shake its head to signal to others. Predators, such as napoleon wrasses, groupers and even moray eels may come over to assist in the hunt (Bshary et al. 2006).

Close up of a giant moray eel on Opal Reef, The Great Barrier Reef. Photo by Richard Vevers, The Ocean Agency, XL Catlin Seaview Survey.

Tool use by the wrasses

Only recently, certain species of wrasses, such as the black spot Tuskfish (Choerodon schoenleinii), yellowhead wrasse and sixbar wrasse, were recorded using corals as anvils to the crack the shells of cockles (Jones and Gardner 2011; Bernardi 2011). Tool use in the wild is associated with complex problem solving that extends the use of something other than a body part. The wrasses would uncover a bivalve, such as a cockle, by wafting the sand away with its fins. The wrasse would then pick the bivalve up using its mouth, swim over to a coral boulder and then pitch the bivalve towards the coral through sideways movement of its head. This action would be repeated multiple times until the shell of the bivalve is cracked and the fish could eat the insides (Bernardi 2011)


A school of Bumphead parrotfish hovers over a coral reef bommie. Photo by Richard Vevers, The Ocean Agency, XL Catlin Seaview Survey
Head butting bumphead parrotfish

On almost every dive along the northern Great Barrier Reef we would encounter schools of bumphead parrotfish, cruising along the shallows and foraging on corals. These fish may look intimidating with their bulbous head and chicklet smile but generally are not aggressive fish. Despite the frequent encounters, I’ve never experienced bumphead head-butting each other to win the favour of a female. This was the experience of scientist Roldan Muñoz and others, while diving in a remote marine reserve in the western Pacific: male bumpheads were observed repeatedly head-butting each other in an epic battle for the right to mate. The sounds that are produced from these repeated head bumps were quite loud and metallic. Encountering this aggressive behaviour also suggested that the marine reserve was also a spawning ground for bumphead parrotfish (Muñoz et al. 2012).

Perfect flatmates – the pistol shrimp and the goby

Living at the sandy edges of coral reefs, the goby sits beside a hole keeping a watch for predators. Meanwhile, his roommate, the pistol shrimp, busily maintains the burrow that they both share, by relocating sand and setting up coral and shell reinforcements along the sides and the opening of the burrow. The pistol shrimp is blind and therefore relies on movements of the Goby’s tail nearby to let it know when danger is around so that it can retreat back into the hole. The pistol shrimp has an enlarged claw that acts as another line of defence. When the claw clamps down, it sounds like a pistol blast, making it the noisiest animal in the ocean (relative to its size), beating even the sounds of whales and other large marine animals. The goby feeds on organisms, such as crustaceans and amphipods that live among the sand particulates stirred up by the shrimp. The shrimp, on the other hand, feeds on mostly detritus, some of it from cleaning the goby. After sunset, both shrimp and goby retreat back into the burrow, which becomes closed in by the end of the night either intentionally, or just from lack of maintenance overnight. In the morning, the goby pushes through the sediment and both goby and shrimp each begin their job of look out and excavator. The survival of the Goby and the shrimp is dependent on due diligence by the two creatures.

References:
Bshary R, Hohner A, Ait-el-Djoudi K, Fricke H (2006) Interspecific Communicative and Coordinated Hunting between Groupers and Giant Moray Eels in the Red Sea. PLoS Biol4(12): e431. https://doi.org/10.1371/journal.pbio.0040431

Jones, A.M., Brown, C. & Gardner, S. Coral Reefs (2011) 30: 865. https://doi.org/10.1007/s00338-011-0790-y

Karplus, I. (1987), The Association between Gobiid fishes and burrowing alpheid shrimps. Oceanogr. Mar. Biol. Ann. Rev., 25, 507 562

Muñoz RC, Zgliczynski BJ, Laughlin JL, Teer BZ (2012) Extraordinary Aggressive Behavior from the Giant Coral Reef Fish, Bolbometopon muricatum, in a
Remote Marine Reserve. PLoS ONE 7(6): e38120. doi:10.1371/journal.pone.0038120



Thursday, November 9, 2017

Do you know where your seafood comes from?


Anjani Ganase, marine biologist, alerts us to the risks in eating seafood of unknown origins. These are some of the questions she suggests that we ask before we purchase.

Growing up in Trinidad and Tobago, I’ve had the luxury of eating freshly caught fish straight off the fisherman’s boat or caught by a family member or friend. We learned to identify the common species of fish that live in our local waters, identify their flavours and how to cook the different fish species. Other countries and cities are not as fortunate as fish is brought from great distances and often pre-packaged and frozen. Unfortunately, more and more fish are being bought in the supermarkets with fewer visits to the local fish depot; and there are fewer occasions of a friend handing over a fresh catch.

It may be that this is still happening. But, according to the FAO (Food and Agriculture Organization of the United Nations) since 2002, the import of fish to Trinidad and Tobago began to exceed local catch and exports. In 2014, we spent about 52.5 million USD to import seafood, which is almost four times the amount earned from our local fisheries (FAO). With more people eating imported fish, there is a need to understand the global fishing industry and how it affects you and your local economy and environment. Here are questions that you should ask about the fish that you eat.

What is it? 

A study done by Oceana revealed that globally, 1 in 25 fish being sold is mislabelled, where the mislabelling can occur at any level along the chain of supply until it reaches the consumer. There are severe consequences to this, especially among fish species that have very different life histories. Knowing what you eat is better for multiple reasons.

Firstly, your health. Consider the higher diversity of fish and other marine life in the ocean: the diets and habits of the fish in the ocean are just as varied - if not more so - as land animals. The top predators – the lions and tigers of the ocean – are the sharks, tunas and swordfish, to name a few, which have very different lifestyles and feed on different prey. Being on top of the food chain, these species of fish build up a significant storage of toxins and organic chemicals that were passed up the food chain. Methylmercury is one of the chemicals that bio-accumulates in the fatty tissues. Health officials have warned that long-term consumption of these fish species can also lead to a build up in your body over time and result in mercury poisoning; symptoms include tremors, numbness or pain in parts of your body, changes in vision and hearing. Species of fish that are high in mercury and should not be consumed include: swordfish, shark, king mackerel, Spanish mackerel, grouper, marlin and Chilean sea bass. There are many other fish species that have low mercury content and are still rich in the necessary fatty acids.

Sustaining fish stocks goes hand in hand with being selective about what you eat. Much of the fish species that are longer-lived predators usually take four to five years to reach maturity and become reproductive. The rapid rates at which humans are removing these fish put them at great risk of a rapid population crash. The biomass of predator fish globally has declined by two thirds over the last 100 years with the majority of this loss occurring in the last forty years (Christensen et al 2014). Furthermore, many fish that are mislabelled turn out to be species that are already overfished and therefore threatened with extinction. For example, an overfished rockfish species was being sold as Pacific Red Snapper in California (Logan et al. 2008). This mislabelling does not help consumers that are trying to do the right thing.

Trinbagonians – as well as others - need to avoid the complacency of not knowing the type of fish we eat. In Australia, for example, the basic term “white fish” is often accepted when purchasing fish from a fish and chips shop. This is a general term where the flesh of the fish is white. Think about this for a second: if you are given a meat pie and you ask what meat is inside, and the response is"red meat," how do you feel?


A fishing net draped over a coral reef is used to catch the fish we eat but it also entraps other marine organisms and damages the surrounding habitat. Fishing practices need to be more sustainable, targeting only the seafood that we want without destroying the habitat or other ecologically important marine life.

 


Where is it from?

When we buy fish straight off the boats near a beach or at fish markets, we are usually assured of fish that is fresh from our coastal and offshore waters. In the freezer department of the supermarket, however, what fish is available? Where is it from?

Fish farms have been growing in numbers over the last decade to balance the demand of fish with the decline in stocks of fish worldwide. The quality of the fish farms depends on the species of fish and how well they do in captivity and the amount of antibiotics being used to to prevent disease. Over the years, the technology behind of fish farms has improved dramatically; the farms can be set up to be environmental friendly and sustainable.

The best quality seafood farms are those dedicated to rearing crustaceans, such as oysters, clams, mussels and scallops. These sedentary filter feeders strain out particulates from the surrounding water column. The majority of these filter feeders are farmed in coastal bay areas, where they are suspended so the concerns you should have will be related to the run off from the land and the pollution in the water column. It is crucial that these farming habitats are regulated to maintain healthy conditions. Of all the farmed seafood these have the lowest environmental impacts as they simply feed on the plankton already existing in the water column and it is the preferred purchase by environmentally conscientious consumers.

If caught in the wild, then how was it caught?

There are many pros and cons to wild caught fish, with the biggest con being the lack of regulation resulting in the rapid depletion of fish stocks. Although some countries have regulations governing pelagic fish, there is no global regulation on what can be caught and how much. The methods used to fish can also be devastating to the marine ecology. The most detrimental of all is shrimp trawling. This method involves collecting shrimp by scraping the bottom habitats and gathering everything into a net. The method destroys the whole ecosystem that is home to the shrimp as well as many other organisms. This includes fish species (mostly inedible), sea turtles, dolphins, corals and other benthic invertebrates. Most of the shrimp trawling for Trinidad occurs in the Gulf of Paria. A study done in 1991 estimated that for every kilo of shrimp being caught, at least 20 kg of demersal fish were caught and discarded. An estimated total of 1,500,000 kg of by-catch, which included demersal fish and other invertebrate life, were estimated to be discarded over the ten-month study period (Maharaj and Recksiek, 1991). Ironically, the Gulf has been a growing industrial coastline over the last thirty years with a considerable amount of pollution run off. I wonder how much viable catch is collected today.

In Tobago, fishing takes place from relatively small-scaled artisanal craft, with significant cultural value to the local communities. While choosing local is always the preferred choice for a greener future, it is also imperative that consumers demand sustainable practices.  For the sake of our health, we must insist that fishermen and consumers alike be educated about the seafood we eat; and the ecological roles they have in maintaining our ecosystems (our surroundings) in the long-term.

References:
Christensen, V., Coll, M., Piroddi, C., Steenbeek, J., Buszowski, J., & Pauly, D. (2014). A century of fish biomass decline in the ocean. Marine Ecology Progress Series, 512, 155-166.

Maharaj, Vishwanie and Recksiek, Conrad (1991) The By-catch From the Artisanal Shrimp Trawl Fishery, Gulf of Paria, Trinidad.Marine Fisheries Review, 53(2), pp. 9-15.

Cheryl A. Logan, C. A., Alter, S. E., Haupt, A. J., Tomalty, K., Palumbi, S. R. (2008) An impediment to consumer choice: Overfished species are sold as Pacific red snapper. Biological Conservation, 141, 1591 – 1599.
FAO website: www.fao.org/fi/oldsite/FCP/en/tto/profile.htm

More information on Oceana seafood fraud campaign:
oceana.org/our-campaigns/seafood_fraud/campaign


Thursday, November 2, 2017

Changing our perception of Sharks

Anjani Ganase, marine biologist, proposes greater respect and a different understanding of the place of sharks in ocean ecosystems

When we think of sharks, we imagine them as bloodthirsty creatures, roaming the deep blue seas for unsuspecting beach-goers and swimmers. Growing up, movies such as Jaws and Deep Blue Sea instilled fear in people and children. Yes, sharks are top predators, but they don’t hunt people; and are important in keeping our marine environments in balance.

Sharks are part of a diverse sub-class, known as Elasmobranchii, which also include skates and rays. Being part of the class chondrichthyes, this means that their structure is made up of cartilage rather than bones. A lighter cartilage skeleton and a tough outer skin makes for lightweight and efficient movement through the water column. There are over 400 species of sharks globally, much higher than breeds of dogs (~340), yet we only hear of the larger, more dangerous species. Here in the Caribbean, we have a subset of species with the most commonly encountered sharks being the Caribbean reef shark, which are shy and smaller than the typical apex predator shark. Caribbean reef sharks are about 1.5 m in length and reside along coral reefs. Other common sharks include the Nurse sharks, which are also residents near coral reefs and have very small teeth (they are suction feeders, so are more likely to give you a hickey than a bite!), and Silky sharks (aka Grey Whalers) that inhabit the open ocean and are very common in the tropics. Finally whale sharks are the gentle giants of the shark species, they can get up to 10 m in length and they roam the open tropical oceans feeding on plankton. Attacks by these common shark species in the Caribbean are extremely rare, and their protection is vital to our healthy ocean and reefs.
Juvenile Caribbean reef shark in Bahamas gets in close to investigate the camera. Photo by Anjani Ganase

Growing up, my irrational fear of sharks prompted me to avoid cross-harbour swims or any open water events. By the time I learned to dive, I hardly got the chance to engage or observe shark behaviour, because of the low number of sharks living among Caribbean reefs after generations of overfishing. But when I moved to Australia to study coral reefs that were protected, I had more shark encounters. Reef sharks are predators but they also compete with other meso-predator fish species, altering their feeding behaviour. Therefore changes in the shark population may shift prey choices of their competitors, which in turn influences the benthic community composition (Roff et al. 2016). A high diversity of shark and fish species indicates a healthy reef. These reefs may be more ecologically stable, meaning that following any disturbance, there are higher numbers of species that can refill functional roles (Roff et al 2016). Sharks also benefit from coral reefs, as reefs provide a diverse foraging habitat for sharks, as well as act as nursery habitats. Unfortunately, in many Caribbean reef systems, sharks and other meso-predators are scarce because of over-fishing.

The first day I snorkelled in the Southern Great Barrier Reef, I was fearful, for I knew I would encounter sharks, even though shark attacks on these reefs were extremely rare. The first shark I met while snorkelling on the reef flat was a Black tip reef shark; and I quickly came to realise that the shark met me with the same fear and curiosity. Most of the sharks I encountered while living on Heron Island came up when I would swim laps in the harbour after work. Swimming up and down this natural pool, I would see sharks seeking shelter from strong currents, escaping the receding tide by dashing off the reef flat into the deeper harbour water, and even chasing fish through the bait ball that gathered at the edge of the wreck.

Whenever I approached the shark, it always kept a safe distance. At times they would come up to investigate and swim away once their interest was met. Four years later, every encounter I’ve had with a shark underwater has been one of cautious curiosity – including a bull shark and an oceanic white tip accompanying us on our dive safety stops; a hammerhead cruising by as if humans were old news; and schools of silver tips, waiting for us as we rolled back for each dive. (All these dives were done in crystal clear and calm waters during daylight hours).

When I surveyed the Caribbean in 2013, there was a stark contrast to Australia’s Great Barrier Reef. The lack of protection over generations essentially meant that sharks were a rarity on Caribbean reefs. The only places frequented by sharks were in Bahamas, which banned long line fishing since the early 1990s (over 25 years), as well as actively protected their habitats. Shark protection has given good returns to Bahamas, as the country earns about 114 million USD annually from tourism based on sharks. Shark diving is the main activity for viewing reef sharks; while swimming and snorkelling with stingrays, and film and television production and research also add to the profits (Haas et al 2017). Sharks are worth much more to the Bahamians alive than as food.

This industry offers bigger benefits to the smaller communities present on more remote islands (Haas et al. 2017). Tourist divers mainly view Caribbean reef sharks; and only at specific locations, such as around the Bimini islands, where the great hammerhead, Oceanic white tip and Tiger sharks congregate (Haas et al. 2017). Globally, shark watching (including whale sharks, great white sharks, tiger sharks and reef sharks) is expanding and soon the economic value of keeping sharks alive, especially along marine protected areas, will outweigh the value of sharks that are killed in fisheries, a trend that may be declining or eventually outlawed. The development of more marine sanctuaries for sharks at Caribbean islands, such as St. Maarten, the Cayman Islands, Grenada and Curaçao means that the shift in the perception of sharks as bad beasts is changing.

Here, in Trinidad and Tobago we also need to change our relationship with sharks. Shark is a known local food delicacy, but this tradition is not sustainable. Traditions have changed in the past through education and understanding that conditions of our ocean have changed. To adapt means to survive, especially with the changing economy of Trinidad and Tobago and our waning natural resource of oil and gas. It is more crucial than ever to change our ways, just as other Caribbean and Pacific Island nations have done. It is time for us to become stewards of our lands and oceans rather than consumers. This is crucial for our children and future generations.
Surveying reefs dominated by reef sharks, Osprey reef 2012. Photo by Richard Vevers, The Ocean Agency/XL Catlin Seaview Survey.

SAFETY AGAINST SHARK ATTACKS
Being educated on the behaviour of sharks and their hunting regimes will significantly reduce your already slim chance of being bitten by a shark.

1. Fishing and spearfishing activities automatically increase your chances of being bitten by a shark, if you are in the water. These are provoked attacks, as sharks are highly stimulated by fish blood and struggling fish.

2. Avoid swimming in areas where there is a lot of baitfish as these also attract sharks.

3. Do not swim at night or at sunset and sunrise; sharks are more active during these times.

4. Avoid murky waters or strong surf as sharks can bump into and mistake people for fish and then can accidentally bite.

5. Shiny jewellery can resemble silver baitfish underwater so remove all jewellery before swimming.

6. Follow all the typical safety rules when swimming by a beach or as indicated by lifeguards.

REFERENCES
Roff, G., Doropoulos, C., Rogers, A., Bozec, Y.M., Krueck, N.C., Aurellado, E., Priest, M., Birrell, C., Mumby, P. J. The Ecological Role of Sharks on Coral Reefs, In Trends in Ecology & Evolution, Volume 31, Issue 5, 2016, Pages 395-407,

Haas, A. R., Fedler, T., Brooks, E. J. The contemporary economic value of elasmobranchs in The Bahamas: Reaping the rewards of 25 years of stewardship and conservation, In Biological Conservation, Volume 207, 2017, Pages 55-63.

Thursday, October 26, 2017

Guests of Honour in Tobago

Faraaz Abdool is an avid wildlife photographer and conservationist. His passion is to record and share the beauty of nature in the hope that future generations would be able to also enjoy the beauty of Mother Earth. In this feature, he asks that we ensure the safety and survival of some very special visitors to Tobago's shores, by preserving the healthy ecosystems on our shoreline and beaches. All photos courtesy Faraaz Abdool

What if I told you that each year, our shores are hosts to hundreds – maybe thousands – of extreme long distance travelers. None of these intrepid voyagers travel by plane, boat or bus. Many of them weigh no more than a few ounces. And all of them have feathers.

Ruddy Turnstones have a short, thick bill that is designed not for probing in the sand, but for flipping stones and small rocks to reveal what’s hiding underneath
These feathered friends are on the run, escaping the cold fingers of the northern winter. They are collectively known as “shorebirds” – unsurprisingly they are usually found near water. That thin line between land and sea is their main habitat. Shorebirds don’t eat a wide variety of food – all of their nutrition comes from various invertebrates they find by probing with their long bills in the mud and sand. This means that they can only eat from very specific locations – sort of like a picky person who will only eat from a certain restaurant. They don’t swim, so they can’t venture into deep water. They don’t dig their prey out of the ground, so they can’t eat where the ground is too dry and hard. This is precisely why coasts and waterways are of such great importance to these migratory birds.

The long legs of the Greater Yellowlegs allow it to wade in deeper waters than other shorebirds
Shorebirds can be found around Tobago, on beaches from Pigeon Point to Charlotteville, as well as  on the banks of slow moving bodies of freshwater. The wetlands of Bon Accord are among their most preferred sites. They can be found from late August to March each year, wintering in the tropics.
A shorebird’s life begins high in the Arctic; many are hatched in the late spring on the tundra of the north. As flowers bloom and food is plentiful, the ground is also soft and rich with food for these tiny birds. Shorebirds are precocial – meaning that from the time they hatch they are already in an advanced state of development – most of them can run around from a few hours after hatching! Such is their level of independence that many of their parents begin their southward migration not long after the eggs hatch. This may seem cruel, but in fact it is to reduce competition for food, ensuring that the young birds have enough to eat to survive on their maiden journeys.

Shorebirds have built-in GPS and impeccable memory. Once they leave the Arctic, they make several stops along the way at what are termed “stop-over-sites”. These locations are not unlike a rest stop and gas station rolled into one; a place where they can rest their wings, refuel, sleep and resume their journey after a few days.

By the time August draws to a close, the first shorebirds start arriving. Of course, the adults arrive first.  The juvenile birds stay a little longer in their Arctic breeding grounds fattening up and growing their first set of feathers for a journey of a lifetime. The young birds know exactly where to go, without a single adult to show them the way. Flying day and night, some of them arrive at the verge of starvation! Before long, areas that were once devoid of birds are now filled with scores of brown and white birds scampering everywhere.

A pair of Sanderlings chases the receding surf
Superficially, they are all very similar. This is because they all occupy a similar place in the ecosystem. They all poke around in the soft mud and sand for invertebrates. They are all painted with various shades of brown, russet and white. Their coloration ensures that they blend in perfectly with the landscape to avoid detection by would-be predators. But as one examines closer, the differences start to appear. Some are big, some are small. Some have extra long legs, some have short legs. Some have short, cute bills, others have very long bills. These finer details give an extra insight into their individual lives. Long-legged birds can afford to wade into deeper water than their short-legged cousins. Shorebirds with short bills will catch food close to and even on the surface of the mud, while longer-billed species can afford to reach deeper into the mud.

Beach specialists like the Sanderling have adapted to a lifestyle of being on the go – these are the birds that seem to madly chase each wave as it breaks on the shore. Every time a wave breaks, tiny invertebrates hidden in the sand emerge for a brief moment in the water. As the wave recedes, there is a tiny window where the little creatures would still be visible – a tiny window which the Sanderling capitalizes upon with a mad dash to the water’s edge. In fact, it’s been running at full speed for so many generations that it has lost its hind toe entirely!

White-rumped Sandpipers have excessively long wings that extend far beyond the tail.
Some species of shorebird spend the entire winter here, in the tropics; others use our available habitats as stop-over-sites on their way further south. In fact, every year some species of shorebird such as the White-rumped Sandpiper migrate from the Arctic to the southernmost tip of South America – and back again! This pole-to-pole migration means that this species in particular undertakes one of the longest animal migrations in the world. How special we must be that this bird will grace us with its presence, albeit for a few weeks each year! This small bird has unusually long wings for its extra-long journey.

Well-camouflaged, this Wilson’s Snipe crouches in the grass. This is the only species of Snipe found on Tobago.
They may seem dull, drab or even inconspicuous, they don’t have the flair of the Motmot or the song of the Wren – but they are most intriguing pieces in the puzzle of life. They are true citizens of Mother Earth herself, and we should be honoured that they choose our shores to spend some time. The preservation of the habitats they feed in is completely essential to their survival as a species – their finicky nature has made them extremely vulnerable to extinction. In fact, the shorebird family has suffered the highest rate of extinction in recent history among avian families. Developments of beachfront as well as tidal lagoons have proven to be detrimental to the survival of these very unique and special birds. Let us all help to ensure that these tiny travelers complete their epic journeys and return safely to their breeding grounds. We can make them at home every year by preserving their feeding grounds.

A Whimbrel manipulates a prey item before consuming it. All photos courtesy Faraaz Abdool

Thursday, October 19, 2017

Oh, Frigate!

Faraaz Abdool is an avid wildlife photographer and conservationist. His passion is to record and share the beauty of nature as art in the hope that future generations would be able to also enjoy the beauty of Mother Earth. Here, he asks us to cherish Trinidad and Tobago’s colony of Magnificent Frigatebirds as he mourns the loss of Barbuda’s colony. (The original version of this feature was first published here: http://faraazabdool.com/2017/09/10/oh-frigates/ )

With the recent obliteration of Barbuda as a result of Hurricane Irma, there is a major concern about the fate of the island’s bird population. Many migratory birds such as sparrows and shorebirds can sense differences in barometric pressure, and either change their migratory route or delay/expedite their travels to suit. Some others may skirt around the storms, and a few intrepid individuals decide to brave the storm itself. In fact, there is a well-known record of a GPS-enabled Whimbrel – a type of shorebird – named Chinquapin that flew directly into Hurricane Irene in 2011.

But what about birds that live in the path of a monstrous hurricane such as Irma? For the endemic Barbuda Warbler, there was nowhere to hide from the hours of howling 180mph winds. Already classified as Near Threatened according to the IUCN – due to habitat loss, its already low population and use of remaining suitable habitat for grazing of domesticated animals – this recent event might have been  the end. However, the Barbuda Warbler has been found in post-Irma surveys; though official numbers are yet to emerge.

Also on Barbuda was the largest breeding colony of Magnificent Frigatebirds in the entire western hemisphere. Estimated at around 100,000 birds, they converge around Codrington Lagoon to nest, raise young and then eventually drift westward toward the Galapagos Islands and elsewhere. I have to say “was” as Irma’s winds reduced to nothing the mangrove islands upon which they usually nest. The lagoon itself has completely flooded out. I’m sure it will regenerate in time. But do the Frigatebirds have the time? The nesting season usually begins in September. So given the time of year, this means that most female Magnificent Frigatebirds (national bird of Antigua and Barbuda) would either have just laid their eggs, or were about to do so.  (At the time of publication, October 19, 2017, we are told that the Barbuda birds are returning to the Lagoon.)

Juvenile Magnificent Frigatebird “practising” the art of picking fish from the surface of the water, using a small twig as a dummy fish. (All photos by Faraaz Abdool)

My heart goes out to not only the affected people, but these magnificent Magnificent Frigatebirds that also stared directly at the beast. It is likely that many of the birds knew what was coming and high-tailed it out of there – except for the ones that had already started to incubate. A comprehensive census must be conducted in due course.

Perhaps some of them may choose to visit our very own colony – if there is any room for newcomers. T&T houses a reasonable breeding population of Magnificent Frigatebirds on the islands of Saint Giles. These islands form the northernmost land mass that belongs to Trinidad and Tobago, and they are home to a few hundred pairs of Magnificent Frigatebirds, as well as other seabird species.
Magnificent Frigatebirds are mostly black with a distinctive angular silhouette. Of the five members of the Frigatebird family, Magnificent Frigatebirds are the largest. They are graceful masters of the air and open ocean as they are able to soar effortlessly for hours without expending much energy flapping their wings. This is because they have the largest wingspan to body length ratio of any bird – this means that they have tremendously large wings for a relatively small bodies. This trait allows them to be very skilful on the wing – something that is necessary for a bird that eats fish but can’t afford to get wet!
Female Magnificent Frigatebird perched. Tobago’s offshore islands are the only place within T&T one would be able to see a perched Magnificent Frigatebird.

Magnificent Frigatebirds live over the ocean, eat fish but if they ever land on the surface of the water, they become waterlogged and drown. Their feathers do not have the waterproofing that other seabirds have. Furthermore, they would be unable to flap their huge wings properly to enable a takeoff from the water. So how do they get their food?

Their high level of maneuverability lets them fly down to the water and deftly pick floating morsels off the surface –  fish or discarded offal from a fishing vessel. They have also been known to eat flying fish that have taken to the air to escape a predator underwater. A now famous clip of the flying fish’s predicament was filmed by the BBC a couple years ago just off St Giles.
What makes them most infamous – and what has given rise to their various names – is their habit of stealing food from other seabirds. Boobies, Terns and Tropicbirds are all smaller than the gigantic Frigatebirds, and once the pirates realize there’s booty to be had, it’s all out war. Harassment can range from simply blocking the flight path to outright attacks; Frigatebirds have been known to grab the tails of the smaller birds until they regurgitate their catch. It is for this reason they are called “Man-o-war” – and even their official name is derived from the word “frigate”, which is a type of fast warship.
Male Magnificent Frigatebird with red gular sac visible, sitting among three adult female Magnificent Frigatebirds.

Magnificent Frigatebirds are generally easy to tell apart from each other. Adult females are the largest, they are all black overall with an easily seen white throat patch. Adult males have no white, but they do have a spectacular red throat that they puff up during courtship. Unlike the female’s white throat which is feathered, this red throat of adult males is actually featherless and is referred to as a gular sac. Young Magnificent Frigatebirds start their lives off completely white, and gradually get their black adult feathers as they mature. Immature birds retain a pure white head until they reach adulthood.

Magnificent Frigatebirds occupy a special niche in the ecosystem of the New World Tropics, and most people have only seen them soaring in the sky, not unlike the illustrations of prehistoric flying reptiles. There are few places in the world where they perch – and our very own islands of St Giles is one of those very special places.

Thursday, October 12, 2017

Living in a warming world

Climate change scientists are monitoring and adjusting the predictions of global temperature rise upward. While the countries that signed to the Paris Agreement of 2015 are working to keep global temperature rise under 2 degrees Centigrade (3.6 degrees Fahrenheit), it is already anticipated that the rise may be higher.

Those monitoring the changing climate have observed that for even one-degree rise, the effects – increased precipitation, stronger deadlier storms forming over warming oceans - seem to be growing exponentially. This year’s hurricane season in the Atlantic may be considered evidence, although scientists are slow to conclude that one season may be part of a trend.

Ordinary citizens, however, must come to decisions about their homes, their livelihoods and protections for their families, in the face of higher storm events, greater flooding, and the effects these will surely have on coastal landscapes. It may seem that an individual, or community, even a country, by itself, is “farting against thunder” to believe that his/ her action might have an effect. However, the actions of individuals can coalesce into collective consciousness and inspire change.  

It is also hard to know whether the warming trend can actually be reversed, or only slowed. Even if we reduced or halted all major carbon producing activities, removed all plastics from our waste stream, do we know whether we have already passed the threshold of safety from deadly storms? Or will the earth, Mother Nature, whatever you call this planetary eco-system of which we are part, require time to assimilate the changes?

The question for the individual remains: how to survive in a world where there is increased incidence of severe storms and flooding; where there may be scarcities of fresh water and food. God may be a Tobagonian, but all it takes is one hurricane, one severe flood, one earthquake to take away our homes, to deprive us of shelter, food, water, safety and security.
Picturesque Charlotteville, north-west Tobago, was badly damaged by hurricane Flora in 1963.

In 1963, 54 years ago – outside the life span of half the population of Trinidad and Tobago - Flora passed over Tobago on its way to becoming a category 3 hurricane. In those days of limited detection (by radar) and even lower communications capability, the tropical storm which started off the coast of Africa (September 26) in the mid Atlantic, crossed Tobago late on September 30. Flora caused tides five to seven feet over normal, sank ships in Scarborough harbor, and brought rainfall so heavy that there was a mud slide from Mt Dillon to Castara. It is estimated the one third of the housing stock of Tobago was destroyed and 75% of forest trees in the Main Ridge Reserve were felled. Agriculture – especially cocoa and tree crops – were devastated and abandoned; a few of these cocoa estates are only now being rehabilitated. 

Flora went on to drop some of the heaviest rainfall ever recorded in the islands of the Greater Antilles: Haiti and the Dominican Republic, Jamaica and Cuba.

Tobago knows the damage that can be inflicted by a one-in-a-hundred-years storm. Even though we may lie outside the statistical path of hurricanes, all it took was one outlier storm a few degrees south of the path to knock down the trees of the Main Ridge Reserve so that it would take another 25 years for the treeline to re-grow.

So what can we do for ourselves? What can we do collectively, as a community, an island, a nation? Should we consider different architecture (roofs that would not lift off in high winds for instance)? How should we protect the shoreline? Should we be thinking of bigger lifestyle changes? Here are some basic notes in case of storms and flooding. What more should we consider, and how should we now act.

CREATE A PLAN
A family plan includes:
Brief all members of your family about what they should do in an emergency: storm, earthquake or other disaster. If members are likely to be away from the home, what should they do. Figure out whether they might be safer in a school or public building than trying to return home. Make an emergency communication plan: what low tech methods might you have to use.

Assess the risk in and around your home: is the location prone to flooding? Are there tall trees around: ensure that branches are trimmed and maintained on a regular basis) Maintain your surroundings and the integrity of your house: clear drains and surrounding bush.
Identify a safe room: on the ground floor, is there a room (a bathroom for instance) that might be a place of safety.

Ensure that the plan includes the animals and pets in the household.

KNOW THE RISKS IN YOUR COMMUNITY
Do you live near the shore? On a hillside? Is there a building (school or church or solid structure) central to the community that might be safer than your home or the beach? Are there elderly persons in your home that might be better relocated before the storm?

DESIGNATE EMERGENCY SHELTERS
If evacuation is necessary, where should the emergency shelters in your village or community be located? Get together with neighbours and determine your safe spots.

HAVE AN EMERGENCY KIT
Create such a kit in a backpack or waterproof bag. Include flashlight, batteries, first aid supplies, critical documents (or copies), medications, cash. Update the kit on a regular basis.





Thursday, October 5, 2017

The Great Barrier Reef observed over five years

Anjani Ganase, marine biologist, returns to the Great Barrier Reef in Australia. In this feature, she warns that we ignore climate change to our peril.

In about week’s time, I’ll be heading out by boat on my final expedition to survey the Great Barrier Reef (GBR) before I return to the Caribbean. This will be the fourth time exploring the GBR, since I first came to Australia five years ago.

The GBR was my first home in Australia. I lived on a research station on tiny Heron Island, located in the southern GBR. I lived on Heron Island for about six months, working on experiments to see the effect of extreme temperatures on corals. During this time, I explored the reefs, viewed migrating whales and followed nesting and hatching turtles on the beach, where the GBR is also their home.

After Heron, I got the dream job as part of a research expedition, surveying the rest of the Great Barrier Reef. Over the next four months my home became a boat and my office the largest coral reef ecosystem in the world. 2300 km in length covering an area of about 344,400 km2, the GBR sits just within the tropical latitudes along the northeastern tip of Australia. In 2012, our team made the amazing effort to survey and map about 1000 km2 of reefs over four months, still less than 1 % of its total area. The first time I explored these reefs in 2012, many sections of reefs seemed almost picture perfect - vibrant and colourful coral cities bustling with fish and marine life. As we steamed north to more remote locations, it appeared as if these healthy sections of reef became more extensive, away from coastal development, ports and agricultural lands. Some reefs are so faraway that sharks and fish approach divers with a curiosity as if they have never engaged with a human and are unafraid of being fished.
Healthy hard coral in the far northern Great Barrier Reef, 2010. Photo by The Ocean Agency / XL Catlin Seaview Survey.

Although the expedition in 2012 was my baseline for observing change on the Great Barrier Reef, the GBR has been home to great scientific research for generations and has been monitored broadly for coral reef health since the 1980s. A compilation of these assessments, released in 2012 while we were doing our own survey, stated that there was a 50 % loss in hard coral cover on the shallow reefs (6 – 9 m depth) of the Great Barrier Reef over the last 27 years (De’ath et al. 2012). Most of this loss was a result of Crown of Thorns outbreak, potentially linked to increased water nutrient pollution (runoff from agriculture), cyclone damage and coral bleaching (De’ath et al. 2012). It was also noted that this decline was not evenly distributed across the GBR; the central and southern regions of the GBR declined significantly more than the northern section, which had a relatively stable hard coral cover over the years (De’ath et al 2012). This statistic overlapped with much of our observations, where the healthiest reefs with the highest coral cover were indeed more common on remote far north GBR reefs. It was necessary for me to adjust my first view observations and judgements, so that I can imagine what these impacted reefs may have looked like 27 years ago.

I was able to visit the GBR two more times since 2012, but most of the subsequent visits followed major disturbance events. In 2014, we specifically visited outer reef sites just off Lizard Island, which were in the direct path of Cyclone Ita, to assess the immediate damage of the surrounding reefs. One week after the cyclone, we witnessed parts of the Ribbon Reef not just stripped of coral but with infrastructure completely turned over; and parts where the framework had avalanched on to deeper parts of the reef. Also apparent was the absence of the usual marine chatter that typically inhabited the living corals.

At the end of 2014, we resurveyed many of our original our surveys from 2012 to assess how reefs changed from two year before. It was clear the impacts that Cyclone Ita had affected, not only in the sections of the reef directly in its path, but reefs much farther away. Within this short time, I was already witnessing significant degradation to reefs I had been introduced to, only two years ago.

In 2016, sections of the GBR again suffered from a different natural disaster, this time it was one of the longest and most severe coral bleaching ever recorded. Overall, higher than average water temperatures resulted in the bleaching being up to four times more severe compared to 1998 bleaching (Hughes et al. 2017). The bleaching event extended to more offshore reefs and the northern sections of the GBR with the southern section being saved by the winds of tropical Cyclone Winston that stirred up the water column. Surveys carried out on the GBR in the months following bleaching found that the heat stress alone was so severe that it was the main prevailing factor for bleaching and death of the corals, even across reefs of varying anthropogenic stress, protection and bleaching history (Hughes et al 2017).  This time, it was clear that climate change driven coral bleaching was the culprit.
Documenting the dead coral overgrown by cyanobacteria after the bleaching event at Lizard Island on the Great Barrier Reef in May 2016. Photo by The Ocean Agency / XL Catlin Seaview Survey.

Considering that many corals may take several decades to recover depending on the species; and there is a predicted increase in temperature anomalies and bleaching events under future scenarios of climate change, the decline in coral cover will likely continue, and even increase in its rate of decline. Local management may not be able to significantly improve the recovery of coral reefs, without active reduction in our carbon dioxide emissions and global warming.

As we survey GBR over the next two weeks, we hope to reveal the cumulative effects of these disturbances over the last five years and taking into account the historical disturbances. We may be able to identify why some reefs continue to prevail while other communities lose following one or other, or multiple, disturbance. I suspect that many of the once pristine reefs that I have observed might be unrecognisable and in a state that is unlikely to recover in my lifetime. It also makes me think about my mentors and their mentors who have been observing changes in the reefs for much longer, over forty years, and I cannot fathom how many reefs that they have witnessed degrade over the years. However I’m also comforted that these experiences only make their drive to present their work to change the minds of citizens, influencing policies and laws, only stronger. I hope that I would be able to do the same, because to resign means to fail our future generations.

De’ath, Glenn, et al. "The 27–year decline of coral cover on the Great Barrier Reef and its causes." Proceedings of the National Academy of Sciences 109.44 (2012): 17995-17999.

Hughes, Terry P., et al. "Global warming and recurrent mass bleaching of corals." Nature 543.7645 (2017): 373-377.

Thursday, September 28, 2017

Meet the Lizards of Tobago's Main Ridge

Amy Deacon, Lecturer in the Department of Life Sciences at The University of the West Indies, St Augustine and Secretary of the Trinidad and Tobago Field Naturalists’ Club continues her series on the biodiversity of the Main Ridge Reserve (MRR). She teams up with herpetologist Renoir Auguste once again; this time to introduce us to the lizards of the MRR. 



 The beautifully patterned Ocellated Gecko is endemic to Tobago. Photo by Renoir Auguste
 
There are at least 17 different species of lizard on Tobago. The majority of this diversity lies within the Main Ridge Reserve. Here, we will meet three of the species most associated with the Main Ridge: the stunningly beautiful ocellated gecko which is found nowhere else in the world; the elusive hex-scaled bachia, a species you probably never knew existed until now; and finally the prehistoric-looking green iguana.

We’ll start by introducing the endemic ocellated gecko. Geckos are a type of lizard, known for their climbing abilities; six species of gecko are found in Tobago but the ocellated gecko is the only one that is unique to Tobago. It is a small species (reaching around 7cm) and undoubtedly wins the title of ‘most colourful lizard on the island’. Males are especially vibrant, sporting a beautiful yellow head, patterned with black and orange spots reminiscent of the markings of a jaguar or ocelot, and bordered by a bright yellow neck ring. The ‘ocellated’ part of their name derives from the pairs of dazzling pale blue eye-spots along the side of their body, which ends in a rusty orange tail. This showy outfit is most likely an attempt to impress females, which have a much more subtle patterning to prevent them from being seen by predators, such as birds. After mating with a suitably attractive male, females will lay a single egg under a layer of bark, although it is common for several different females to lay their eggs in the same place for added protection.

In the MRR, the ocellated gecko is most often seen on stream-side tree trunks, but it may also be spotted in less pristine settings outside the reserve, for example it is frequently seen scuttling around deserted buildings. If you sit and watch one for a few minutes, it becomes clear that males are very territorial, and tend to inhabit and defend a particular area with one or more females nearby. It is diurnal (active in the daytime) and is considered an ambush predator, pouncing upon unsuspecting insects and land snails that come a little too close.
This strange looking lizard is the Hex-Scaled Bachia, which makes its home in the leaf litter of the Main Ridge Forest. Photo by Renoir Auguste

It is unlikely that many readers will have heard of the strangely-named hex-scaled bachia lizard, let alone seen one. Even if you are lucky enough to catch a glimpse of this bizarre-looking creature, at first glance it could be confused with a worm or small snake. It has a slender body with surprisingly short limbs relative to its body length (reaching about 16cm long). It is named after the distinctive hexagonal shaped scales on its back; yet another lizard named after its morphological features. Like the ocellated gecko, the hex-scaled bachia lizard is diurnal and feeds on a variety of small leaf-litter invertebrates, although its favourite food is termites. As a result, this species makes its home in the leaf litter and soil of the forest floor, where it can find plentiful food and a safe place to nest. Given that bachia lizards appear to spend the majority of their life hidden under the leaves, is not surprising that they are rarely seen!

A lizard that everyone will be familiar with is the green iguana – although not everyone realises that it is officially the largest lizard in the western hemisphere! This lizard can reach up to 2 metres long at maturity and has a wide distribution in the region, from Mexico to Brazil. Juveniles and females are an incredible bright green colour, while adult males may be silvery grey, and can turn red-orange during breeding season. Females construct nesting burrows to lay their eggs in. Here, they are sometimes predated on by another lizard – the tegu, also known as the matte. It is not just their eggs that are vulnerable to predation; juveniles and adults may be preyed upon by snakes, raptors, cats, and especially humans. Indeed, iguanas are perhaps the most hunted reptile in the country. Of course, it is illegal to hunt iguana (or any animal) inside the MRR at any time of year. However, with a permit, iguanas can be legally hunted outside of the MRR during open season (October –February).
Green iguanas can be found almost anywhere on Tobago, from the primary evergreen forest of the MRR, to mangrove swamps and urban parks and gardens. As they are active during the day they are often seen wandering around or basking in the sun. Unlike most of Tobago’s lizards, which prey upon insects and other small creatures, iguanas are strict vegetarians. In fact, they have a specialized digestive system for processing difficult-to-digest plant material. They are also surprisingly good swimmers and are known to dive into water to avoid potential predation when disturbed.

The majestic Green Iguana. Photo by Renoir Auguste
Despite being closely related to snakes (both snakes and lizards are reptiles of the order Squamata), for some reason lizards seem to provoke less fear in people, and have an easier time being liked – apparently we are less suspicious of creatures with legs! Legs or no legs, our reptilian neighbours play an important role in the ecosystem by acting as predator and prey to a variety of animals – not to mention the role that iguanas play in dispersing seeds that they do not digest. We should also be grateful for the lizards that share our gardens and homes, providing a natural pest-control service for mosquitoes and cockroaches. In return, we should take care with the chemicals we use in the house and garden so as to encourage this mutually beneficial arrangement, and ensure that their forest home in the MRR continues to be preserved for many years to come.

Thursday, September 21, 2017

The effects of hurricanes on coral reefs


Anjani Ganase, marine biologist, looks at how hurricanes affect coral reef ecosystems

Coral reef ecosystems are shaped by their surroundings. The amount of light they receive, the temperature of the water column, even the movement of the water (currents) all govern whether a coral species can survive and reproduce. As corals are only mobile during their larval phase, the spot where they choose to settle and grow becomes a very important choice; not too hot or cold, just enough light and shelter. As a result, we find shifts in coral reef types as environments change. However, despite a coral’s ability to adapt to long-term environmental conditions, similar to us on land, coral reefs can also be devastated by large disturbances that bring destruction or death. One example is hurricanes.

Hurricane force winds uproot trees and damage infrastructure on land. These same winds drive intense wave surges along coastlines, causing violent and irregular water movement that can be felt at great depths. Water movement is a part of a coral’s life, especially those living in the shallows, where the shape and size of the coral might be determined by the rhythmic movement of the water. However, the powerful waves generated by the hurricane can break and overturn even the hardest coral structure. Damage at greater depths is two-fold, directly breaking corals because of surging water; and secondly, from debris falling from the shallows.

Apart from the physical stress that the surging waters exert on the reef benthos, the turmoil of water movement from hurricanes also tends to mix the upper portions of the ocean’s water column, homogenising water conditions to the depths. Usually, seawater becomes naturally colder and saltier with depth; and organisms pick and choose the depth that best satisfies their needs. Drastic changes in temperature, salinities, oxygen concentrations and other conditions can result in death of small fish and invertebrates, such as lobsters that are unable to tolerate the extremely low salinities as a result of the excess rainfall. Larger mobile creatures, including bigger fish, sharks and marine mammals can escape the hurricane by moving to other areas. One study on black tip sharks observed that they moved away from the reef when hurricanes approached and returned following the storm, and suggested that the sharks were able to detect changes in the surrounding pressures driven by the storm (Heupel et al. 2003).


BEFORE: A healthy coral reef on the Great Barrier Reef before being hit by a category 5 cyclone (Cyclone Ita). Photo by XL Catlin Seaview Survey
AFTER: The same coral reef after being hit by a category 5 cyclone (Cyclone Ita). Photo by XL Catlin Seaview Survey

The effects of hurricanes may still be felt days after the storm has moved on. Waters can continue to surge days after a hurricane. In addition, the runoff from the land can carry sediment down to the coastal ecosystems, burying corals and muddying the water column blocking out the sunlight. The large amount of fresh water run off from the rivers also continues to reduce salinity. The recovery of the corals and associated marine life, greatly depends on subsequent disturbances, whether it is another hurricane or man-made, as well as whether the long-term environmental conditions continue to promote coral recruitment and growth.

On longer time scales, the frequency of hurricanes experienced in an area also governs the resultant community composition of coral reefs. Some locations in the Caribbean are hit more frequently by hurricanes, such as the Bahamas, which is impacted by hurricanes almost annually. In contrast, Trinidad and Tobago, the southernmost islands in the Caribbean, have a history of very low hurricane disturbance. The time between hurricane impacts on coral reefs in the Bahamas is much shorter compared to that in Trinidad and Tobago. This means that coral reefs in the Bahamas are likely to be very different to Tobago’s. Bahamian reefs are therefore likely to be composed of species that have faster growth rate, and therefore able to recover quickly between storms.

Studies have shown that full recovery of coral reefs (regrowth of corals) following a hurricane can be as quick as five years if no other storm hits. However, it has also been shown that overall Caribbean reefs have become impaired in their ability to recover from hurricanes; they recover at a slower rate (> 8 years) if at all, to their pre-disturbed states (Gardner 2005). Sometimes the recovery is too slow to allow sufficient regrowth of coral skeleton before another hurricane passes. This recovery impairment of corals can be related to additional stressors that are experienced by the corals. Interestingly, the impacts of hurricanes on coral reefs were more intense during the 1980s, but this does not mean that hurricanes have become less damaging to coral reefs (in fact, we know that hurricanes have become more intense over the last forty years); rather coral reefs are being more damaged by other disturbances at a greater rate. These other disturbances are typically man-made, which alter the long-term living conditions of the reef environment making it less suitable for corals. 

On top of the standard management of coral reefs that is important to sustain long-term coral health, there is need for a recovery management plan for reefs following significant disturbance events. If a coral reef has been badly damaged following a hurricane, areas of severe coral loss should be temporarily closed to fisheries and recreational use in the following years. This will reduce the number and frequency of stressors acting on the reef and help the reef to recover. Furthermore, any nearby land-based activity that may affect the reef should also be limited and monitored closely until the reef has recovered to a state where it can once again act as a buffer to other disturbances.

References:
Gardner, T. A., Cote, I. M., Gill, J. A., Grant, A., & Watkinson, A. R. (2005). Hurricanes and Caribbean coral reefs: impacts, recovery patterns, and role in long‐term decline. Ecology, 86(1), 174-184.

Heupel, M. R., Simpfendorfer, C. A., & Hueter, R. E. (2003). Running before the storm: blacktip sharks respond to falling barometric pressure associated with Tropical Storm Gabrielle. Journal of fish biology, 63(5), 1357-1363.

Thursday, September 14, 2017

Climate change, like hurricanes, calls for non-partisan policy and responses


Anjani Ganase, marine biologist, discusses the response of small island states to extreme events like hurricane Irma. This feature was first published in the Tobago Newsday, September 14, 2017

In the wake of hurricane Irma, the strongest hurricane ever recorded in the Atlantic basin closely followed by hurricane Jose, the question of whether climate change is affecting the frequency and intensity of hurricanes in the Caribbean has once again come into question. Unfortunately, at the moment there is no certainty of whether the intense and frequent hurricanes of a single year are a result of human induced trends. Only future observations over multiple years and a better historical cyclone record will allow us to determine whether these trends are part of a long-term natural cycle or the result of a warming planet. What we do know, based on the climate assessment reports provided by the intergovernmental panel on climate change, (IPCC) is that cyclone activity in the Atlantic basin has been increasing since the 1970s. It is also predicted (although unlikely to be detected at the moment) that the frequency of more intense hurricanes is likely to grow as a result of warmer sea surface temperatures (IPCC Report 2013). Warmer water results in more water vapour, which fuels the hurricane system.
 
The NOAA satellite captures a geocolor image of Hurricane Irma as it passes the eastern end of Cuba. Photo credit: NOAA/CIRA
The IPCC predicts the effects of warmer atmospheric temperatures on small-island nations, some of which will certainly occur over the next 100 years. One major problem is sea-level rise, and the myriad issues that come with it, including coastal erosion, especially during periods of storm surge and high wave activity. Seawater will undermine infrastructure; contaminate ground water and sewerage systems, as well as freshwater ecosystems. Current observations show that the Caribbean has a mean sea-level rise rate of 1.8mm/ year, which is similar to the global average, while sea-level rise around the Pacific islands is increasing at a much faster rate. In regard to other weather patterns, under both future scenarios (business as usual carbon emissions and reduced carbon emissions), it is expected that warmer atmospheric temperatures will result in extended dry seasons and droughts in the southern Caribbean, while there will be more rainfall during the wet season in the northern Caribbean. All these changes will have direct impacts on the ecosystems – watersheds, agricultural lands, wetlands, mangroves and coral reefs - that we rely on for our livelihoods.

It is virtually certain that global mean sea level rise rates are accelerating.  Projected increases to the year 2100 (RCP4.5: 0.35 m to 0.70 m) superimposed on extreme sea level events (e.g. swell waves, storm surges, El Niño-Southern Oscillation) present severe sea flood and erosion risks for low-lying coastal areas and atoll islands (high confidence).- IPCC

Other ecological impacts from warmer conditions include the potential increase in the transmission of diseases, including vector borne diseases such as Zika, Chikungunya and Dengue that infect our population, as well as other diseases that can infect flora and fauna. Furthermore, cases of respiratory illnesses, such as asthma and allergies related to the dust clouds originating from a more arid Sahara basin and travel across the Atlantic to the eastern Caribbean is also expected to increase  (IPCC Report 2014).

WHAT DO WE NEED TO DO?
Adaptation to climate change generates larger benefit to small islands when delivered in conjunction with other development activities, such as disaster risk reduction and community-based approaches to development (medium confidence). Addressing the critical social, economic, and environmental issues of the day, raising awareness, and communicating future risks to local communities will likely increase human and environmental resilience to the longer-term impacts of climate change.” – Recommendation by the IPCC

Whether it is stronger hurricanes, sea level rise, drought or biological invasion, it is crucial that governments heed these warnings and work out transparent plans to reduce the risk of impact. Trinidad and Tobago has been fortunate to have a stable economy from the oil and gas industry but there is need for major investments into mitigating impacts. This should be done with transparency and with community engagement, so that climate awareness and action enter our homes and lives. While maintaining infrastructure and instilling stricter policies on housing and business development (especially development near important ecosystems and along coastlines and river ways) will help reduce economic damage, much of the future relies on the protection of our natural ecosystems and community awareness.

Most of our major towns in Trinidad and Tobago – Scarborough, Port of Spain and San Fernando - lie on the coasts. The Caroni and Nariva swamps collect much of the water from rainfall and will buffer the inundation events of the sea during storms. Keeping these waterways clear will help flood-prone areas. Preserving mangrove areas will reduce the damaging effects of storm surge. Coral reefs also act as natural wave breaks against storm surge, and the protection of the reefs from over-exploitation and pollution will give them the best chance to adapt to changing climate conditions and therefore to continue to serve their important economic roles. Preserving the rainforest, stricter laws on deforestation and squatting on watershed areas, will increase the storage capacity of water reserves and reduce wasted water, especially important during times of drought.

Another major problem noted by the IPCC is: the inaction inherent in the mismatch of the short-term time scale on which government decisions are generally taken compared with the long-term time scale required for decisions related to climate change. Governments need to implement policies that mandate climate change infrastructure; on the understanding that such policies must be non-partisan by nature, so that policies cannot be overturned from one government administration to the next.
 
Low lying islands, such as Malé the capital of the Maldives in the Indian Ocean, are under threat of rising sea levels. Photo credit: Shahee Ilyas (https://creativecommons.org/licenses/by-sa/3.0/)
Link to the latest IPCC Reports: