Aldabra Expeditions - Eco and Dive cruise with Silhouette Cruises Ltd

1. Sharks are vital to the ocean food chain, and in keeping the overall population healthy with weeding out sick or injured animals. They are also key elements in maintaining the right ratio between species.

2. Sharks can also boost tourism. Ok, not in the Hollywood movies, but in real life shark diving is a growing industry.

3. Sharks are perfectly-engineered. Scientists study sharks for several reasons: for their efficient moving in the water, their skin, and even bacteria-resistant surfaces.

4. Sharks can help reduce carbon in seas by eating dead fish that collect on the seafloor.

+1. They are one of the earthlings, and part of the biodiversity. :)

We eliminated one of the points as it was about eating sharks, as in our opinion this is absolutely unacceptable.

Two tropicbirds, a red-tailed and a white-tailed incubating their eggs.

When it comes to breeding site, Red-Tailed and White-Tailed Tropicbirds prefers Aldabra... The two species nest mainly on islets in Passe Femme, south of Picard. The collected information in the past 7 years' monitoring program helps to investigate the factors that influence breeding success and why they might be different for each species.

Source: SIF FB

Under the #timingiseveything a new photo collage was posted on the SIF Aldabra Reserach Team's FB page. The post reminds us how fragile a turtle population is.

The number of eggs in a nest (clutch) varies by species. On average, turtles lay 110 eggs in a nest. The largest clutches are laid by hawksbills, which may lay over 200 eggs in a nest. Once the female completed the nesting, she never returns to it. 

The nest's temperature determines the hatchling's gender. Warmer temperature produces mostly females, and cooler temperature produces a majority of males. (Another unfortunate side effect of global warming can be it's result on future population's gender rate.) Turtle eggs look like ping-pong balls, with a soft shell.  
Mortality rates for turtle eggs are high due to predation by ghost crabs or humans. Some nests are laid to close to the tide line and if not relocated will be lost.

When the time comes and hatchlings break free from their shell inside the egg chamber, they stimulate the others to emerge from their eggs too. Once most hatchlings have emerged from their shells, they climb on top of each other and the discarded eggshells til they reach the top of the chamber. They emerge either en masse or in small groups, but emerging together increases the chance of survival. Sea turtles are attracted to light, therefore they are guided by the moonlight reflecting on the sea. As a result of light pollution (street lights, house & hotel lights) they may become victims of predators or accident. If hatchlings delay in emerging from the nest, the heat of the sun also may harm them. On the way to the sea
The dangers are not over,  on their way to the sea, predators as crabs, birds, fish and sharks are waiting for them. If they survive all these, human caused threats as fishing gear (long line), ingestion of marine debris, boat strikes, trash on beaches and pollution also harms the population.
As a result, only one hatchling in a thousand make it to adulthood (15-25 yrs).

In Aldabra itself, crabs, crows and herons are waiting for the newly emerged hatchlings on the shore, and many blacktip reef sharks in the shallows. Only a very lucky few reach the open sea's "safety".

Source: Sea Turtle Conservancy
Photo: SIF Aldabra FB page

For many years we are aware of it, that most chemicals are harmful for underwater life, but the study, that even one drop of sunscreen is enough to damage fragile coral reef systems is only known since the past years.

Above we are talking about one drop, but in reality some 14,000 tons of sunscreen lotions wind up in coral reefs around the world each year. The ingredient oxybenzone is causing coral bleaching, and it can also disrupt the development of fish and other wildlife.

Scientists conducted the study in the U.S. Virgin Islands, Hawaii and Israel, but the results are worldwide. Reefs are in general at risk, due to destructive fishing, pollution, global warming and development all pose threats to the coral reef.
"The use of oxybenzone-containing products needs to be seriously deliberated in islands and areas where coral reef conservation is a critical issue," co-author Craig Downs said according to the Washington Post. "Any small effort to reduce oxybenzone pollution could mean that a coral reef survives a long, hot summer, or that a degraded area recovers."

Local economies, as ours in Seychelles depend on the tourism that coral reefs attract. As a result, we shall completely ban the use of harmful sunscreen in their waters. There are good examples, in Akumal, Mexico, an area known for its reefs and sea turtles, visitors are warned against wearing sunscreen and are restricted to certain areas to prevent too much disruption of reef life.

Damaging sunscreen from beachgoers is just part of the concern. When people wear sunscreen, it is anyway going to end up in the waterways, after cleaning it off, just like other chemicals used by in household cleaning products. These are all washed down into the sewage systems.
"People come inside and step into the shower. People forget it goes somewhere," co-author John Fauth told the Post.

To avoid harming coral reefs, use "reef friendly" sunscreen (those made with titanium oxide or zinc oxide, which are natural mineral ingredients) and wear clothing and hats to protect the skin from the sun.