Jul 7

The Galápagos archipelago is known for its extraordinarily rich abundance and diversity of native plants and animals found nowhere else in the world. However invasive species present on islands are threatening the Galápagos’ rare species, pushing many to the brink of extinction. To date, seven vertebrate species have become extinct, while 40% of the still existing 96 species are endangered – with invasive species as the primary threat.

The world’s only marine lizard, the endemic Galápagos marine iguana, is extremely vulnerable to invasive species which consume the young and even occasionally adults

Island Conservation began working to protect species in the Galápagos Archipelago in 2008. In 2011,  the Galápagos National Park, supported by Island Conservation, Charles Darwin Foundation, The Raptor Center, and Bell Laboratories, removed invasive rats from the islands of Rábida, North Plaza, three Beagle islets, and three of the Bainbridge Rocks to protect 12 unique Galápagos species considered by the International Union for Conservation of Nature to be threatened with extinction.  One success story from this project was the rediscovery of a land snail species on Rábida Island, which was presumed to be extinct as no live specimens had been observed or recorded since 1905-1906.

In 2012, work began to remove invasive species from another island in the Galápagos Archipelago, Pinzón Island. Over 150 years ago, invasive black rats invaded this island and began feeding on the defenceless eggs and hatchlings of the Pinzón giant tortoise. By the turn of the 20th century the island endemic tortoise was unable to establish its next generation of tortoises, resulting in a captive rearing program being set up.

Pinzon giant tortoise 2

Adult Pinzón giant tortoise © Island Conservation

By December 2012, the project to remove the invasive rat species from this island was completed. With the removal of the last remaining invasive vertebrate species threat, tortoise hatchlings are now emerging from native tortoises on the island and the Galápagos National Park have successfully returned 118 hatchlings to their native island home.

The removal of invasive species from these islands is part of a much larger project to restore other key Galápagos Island ecosystems to protect native plants and animals. The next major endeavour is to remove multiple invasive species from Floreana Island. Feral goats have already been removed from the island, but other invasive species remain which are a threat to the island’s rich biodiversity. This rich biodiversity includes the Critically Endangered Floreana mockingbird which has disappeared from the island, mainly as a result of invasive species. Now only surviving on two small neighbouring islets, the removal of invasive rats and cats from Floreana will allow for this bird to comeback from the brink of extinction.

The Critically Endangered Floreana mockingbird

To find out more about the great work that Island Conservation carry out, visit their website or facebook page.

Find out about more South Pacific Islands on Arkive.

May 27

Everyone remembers their first encounter with a whale shark, just as we all remember that first kiss, but experience has taught me that each encounter is in some manner just as unique as the first time.

When I first began diving the northern islands of Wolf and Darwin in the late 1980´s, we really had no idea of the species that we were going to find. Already Darwin´s Arch had begun to get the reputation as being the best dive site in Galapagos. Within days of my arrival to these distant shores I heard rumours of schooling hammerheads, Galapagos sharks and the strangely named ¨Pez Gato¨ or ¨catfish¨ as the fishermen referred to whale sharks. I later learned that the white spots on a whale shark where likened to those of the jaguar. Perhaps some of the fishermen had spent some of their formative years in the Ecuadorian Amazon jungle!

1 Whale Shark with Creole fish - Jonathan Green

Whale shark with creole fish © Jonathan Green

As time progressed we became aware that the whale sharks were aggregating on a seasonal basis, much more frequent during the cold garua season between June and November. The larger animals were thought to be males, although as with many shark species the female whale sharks are larger on average than males. It was only when we began actively checking for male claspers that it became apparent that most of the sightings were actually of females.

By the beginning of the new millennia I was already convinced that most of those whale sharks that passed by Darwin were not only adult females, but that they were also pregnant! Their distended abdomens appear to confirm this, but how could we get solid scientific evidence? It’s not so easy when they average over 10 m in length and weigh upwards of 20 tons. Researchers working with other large pelagic sharks such as tigers and great whites are able to capture the animal and carry out certain medical procedures in a controlled environment, much as we do with humans. The shark is winched onto the deck and immobilised and although there are strict time limitations, blood samples may be taken and an ultrasound test carried out.

1 Whale Shark - Jonahtan Green

Whale shark © Jonathan Green

This is simply not possible given the size and nature of the whale shark, so how do we propose to do this? Certainly a challenge as this has never been tried before. Blood samples have been taken from captive whale sharks, but never ¨on the fly¨. Picture a diver with no means of propulsion but his fins and leg muscles, chasing down an animal the size of a single decker bus with a 4 knot current in a thousand feet of water! Sound exciting?

Next season we hope to have members from the Georgia Aquarium join us in the field to attempt taking a blood sample from a whale shark in the wild, for the very first time. They already have extensive data of the blood chemistry of captive juvenile female whale sharks that are not pregnant. By comparing the blood chemistry of a female in the wild that we are 90% certain is pregnant, we may be able to determine how close to birthing she is. We also hope to try the worlds first underwater ultrasound using a waterproof prototype unit that is self contained and can record video and still images. Perhaps this will give us an indication of the stage of development of the embryos, as well as numbers of pups. Each encounter with a whale shark provides us with more information.

Alan Purton

Whale shark © Alan Purton

Developing new techniques in order to answer some of the many questions that still remain about their natural history has always held great appeal, for it is that voyage of discovery and the resulting data that may help protect whale sharks in the future, wherever in the world they roam.

If you would like to learn more about the project in Galapagos and how you can get involved, visit whalesharkappeal.co.uk.

Apr 24

Amongst the black lava rocks that line the wave-lashed edges of the Galapagos Islands, the world’s only sea-going lizard can be found.  Amblyrhynchus cristatus, the marine iguana, is a remarkable and well-known endemic reptile of the Galapagos Archipelago.  Though widespread and highly abundant on certain islands, small, declining and genetically distinct populations on other islands are causing concern for conservationists.  One population in particular, found at the very tip of the easternmost island of San Cristobal has garnered attention not only for its critically small size, but also for being highly distinctive in genetic terms.  This ‘Punta Pitt population’, named after its location, is so genetically distinct that we are investigating whether it deserves recognition as a new species or sub-species.

image 3

A marine iguana at Isla Lobos, San Cristobal Island. Larger males, like this one, swim and dive to forage on sub-tidal algae, whereas smaller individuals graze along the intertidal zone

 Since 2012 we have travelled to San Cristobal each year to collect information and new samples that will teach us more about Punta Pitt iguanas.  Before we started, iguanas on San Cristobal were known from only two colonies which seem not to interbreed with one another.  We began in 2012 by sailing around the island and sampling iguanas wherever we encountered them.  We found and sampled many new colonies, all on the west coast.  The entire eastern side of the island, wild and wave-battered, sadly eluded us.

Processing samples in the field at La Galapaguera, where Punta Pitt type iguanas are found

Processing samples in the field at La Galapaguera, where Punta Pitt type iguanas are found

image 1

Weighing a young iguana at Islotte Pitt

In 2013 we returned to San Cristobal, this time to take a closer look at Punta Pitt and investigate the threat posed by feral cats, known to eat marine iguana hatchlings.  We camped at a remote beach for seven weeks.  During this time we fitted four feral cats with GPS-enabled radio collars and followed their movements.  We also collected measurements, samples and photographs of marine iguanas in order to investigate both physical and genetic differences between iguanas on the island.  Though we were only three people at the camp, we were certainly not lonely; the resident mocking birds, as curious as they are comical, watched our every move.  Constant vigilance was needed to prevent the legion of local hermit crabs from stealing all manner of things, and most evenings provided a cascade of newly hatched green turtles on the dunes, making their way down to the sea.

The resident mocking bird, who assumed ownership of all our things at camp (especially any unguarded porridge)

The resident mocking bird, who assumed ownership of all our things at camp (especially any unguarded porridge)

Frigate birds oversee the dish washing at camp

Frigate birds oversee the dish washing at camp

IMG_0188

The finches give our packing boxes a close inspection

Galapagos_April_2013 159

Newly hatched green turtles begin their journey down the dunes to the sea at Salinas beach

We are now in the midst of the final field-season of my PhD.  This season will be shorter, and we intend to find a way to sample the East coast.  This will involve searching for safe landing sites with an experienced fisherman, and a lot of walking along lava rocks.  If we are successful, we will have surveyed and sampled almost the whole island.  Back in Germany, we are working hard to analyse the morphological and genetic data that will tell us whether or not Punta Pitt iguanas are a new species.  In any case, the information we have gathered here in San Cristobal will be a valuable contribution to assessing the conservation status of marine iguanas on this island, where their population is the smallest of any of the Galapagos Islands.

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Punta Pitt type iguanas on the headland at Playa Cafe, the white cross is a temporary mark which indicates a sampled iguana

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Amy MacLeod is in the final year of her PhD at the Technische Universität Braunschweig in Germany. You can contact her by email at ms.amymacleod@gmail.com

Nov 9
Floreana coral

Floreana coral (Tubastraea floreana)

Species: Floreana coral (Tubastraea floreana)

Status: Critically Endangered (CR)

Interesting Fact: The polyps of Floreana coral are bright pink in the water, and dark red-black when dry.

More information:

Found in the Galápagos, Floreana coral is a scleractinian coral, which means that it is a hard coral with a limestone skeleton.  Floreana coral is known as an ‘azooxanthellate’ coral, as this species does not have zooxanthellae, the algae that live inside the tissues of some corals and provide the corals with food. Corals without zooxanthellae instead feed on zooplankton, capturing these tiny aquatic animals in their outstretched tentacles. Floreana coral can be found on ledges, overhangs and the ceilings of caves, at depths of between 2 and 46 metres.

Now classified as Critically Endangered (CR) on the IUCN Red List, and listed on Appendix II of CITES, the Floreana coral is thought to have once been fairly widespread around the Galápagos Islands. However, since the El Niño event of 1982-1983, this coral has only been seen at Cousins Rocks and Gardner Islet. Despite searches specifically for this species, the Floreana coral has not been seen at Cousins Rocks since 2001. This indicates that any alterations to the water temperatures surrounding the Galápagos Islands are likely to threaten this coral and cause further mortality.

The unique biodiversity of the Galápagos Islands and the surrounding waters is recognised and valued, and the region is protected by being designated a Marine Reserve and World Heritage Site. Any international trade involving the Floreana coral is carefully regulated thanks to CITES. Unfortunately, neither of these measures protects this Critically Endangered coral from the threats of natural, or man-induced, climate change.

 

Find out more about the Floreana coral at Earth’s Endangered Species, and more about the Galápagos Islands at the Charles Darwin Foundation.

See images of the Floreana coral on ARKive.

 

Phoebe Shaw Stewart, ARKive Text Author

 

Jun 25

Lonesome George, a Galapagos giant tortoise believed to be the last of his subspecies, has died, according to Galapagos National Park officials.

Photo of male Abingdon Island tortoise - Lonesome George - resting

“Lonesome George”, the last of his subspecies

First seen by a Hungarian scientist on the Galapagos island of Pinta, or Abingdon, in 1972, Lonesome George became a symbol of the Galapagos Islands. With no other known individuals of his subspecies left, George had the unfortunate distinction of being considered the rarest animal in the world.

Giant tortoise declines

Galapagos giant tortoises were once so numerous that Spanish explorers named the Galapagos archipelago after them. However, these large reptiles were hunted by sailors and fishermen for their meat and oil, and more recently have suffered habitat loss and competition due to introduced goats and cattle. Introduced predators such as cats, dogs and rats also predate the more vulnerable juveniles.

Photo of Galapagos giant tortoise hatchling breaking out of shell

Young Galapagos giant tortoises are vulnerable to introduced predators such as cats and rats

There are a number of different subspecies of Galapagos giant tortoise, and the differences in appearance between the tortoises from different islands were among the features that helped Charles Darwin develop his theory of evolution.

Overall, around 20,000 giant tortoises are thought to now remain on the Galapagos Islands, but three subspecies have already become extinct or are extinct in the wild.

Photo of an old male Duncan Island tortoise in typical habitat

Duncan Island tortoise. Some Galapagos giant tortoise subspecies have “saddleback” shells, while in others the shell is more domed.

Failed breeding attempts

Despite efforts by conservationists to breed George with females from closely related giant tortoise subspecies, he sadly failed to reproduce successfully. With his death, the Pinta Island subspecies, also known as the Abingdon giant tortoise (Chelonoidis nigra abingdoni), is the latest giant tortoise subspecies to become extinct.

Lonesome George was estimated to be around 100 years old at his death, although Galapagos giant tortoises can potentially live up to 150 years or more. Park officials are due to carry out a post-mortem to determine the cause of his death.

Photo of male Abingdon Island tortoise - Lonesome George - feeding

Lonesome George feeding

Conservation efforts

Fortunately, conservation efforts are underway to save other Galapagos giant tortoise subspecies. For example, a programme running since the 1970s raises hatchlings in captivity until they are large and robust enough not to succumb to predators in the wild.

This programme has shown encouraging success, increasing the population of the Critically Endangered Hood Island tortoise (Chelonoidis nigra hoodensis) from just 13 individuals in the 1970s to over 1,000 in the wild today.

Read more about Lonesome George at BBC – Last Pinta giant tortoise Lonesome George dies.

View photos and videos of the Galapagos giant tortoise on ARKive.

Liz Shaw, ARKive Species Text Author

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