Tag Archives: Galapagos

Lionfish

Marine Invaders Threaten Galapagos

Increasing tourism and the spread of marine invasive non-native species is threatening the unique undersea life around the Galapagos Islands.

Scientists from the UK Universities of Southampton and Dundee are currently investigating the extent of the problem.

Project leader Dr Ken Collins of the National Oceanography Centre said:
“Tourism is partly to blame for the influx of invasive non-native species, due to the huge rise in ships and planes from mainland Ecuador bringing in pests. In recent years, it was realised that cargo ships were carrying disease-infected mosquitoes, which were attracted to the ship’s bright white deck lights. Simply changing from conventional filament bulbs to yellow sodium lamps, along with fumigation in the hold has substantially reduced the threat.

“We are trying to protect marine biodiversity by identifying newly arrived species to the Galapagos, assessing if they have the potential to compete for space and overcome other species of algae and native corals.”

One species causing concern, which has the potential to overwhelm natural populations, is the Indian Ocean lionfish. This fish colonised the Caribbean through accidental release from an aquarium and has spread through the entire Caribbean in the last decade. it is in equilibrium in its natural evironment, but in the southern Caribbean its rapacious appetite has led to the decimation of coral reef fish populations. Lionfish can consume prey up to two thirds of their own length and data shows that they can eat 20 small wrasses in 30 minutes. Their stomachs can expand by up to 30 times in volume when consuming a large catch. The Panama Canal could provide a short cut to Ecuador’s Pacific coast and then the Galapagos.

Preliminary evidence suggests that lionfish are less invasive where large predatory native fishes are abundant.

Prof Terry Dawson, SAGES Chair in Global Environmental Change at Dundee, says,
“Invasive species are becoming one of the greatest threats to biodiversity on a global scale. The Galapagos islands are particularly vulnerable due to the fact that much of the indigenous wildlife have evolved over millions of years in the absence of predators, competition, pests and diseases, which makes them very susceptible to the negative impacts of aggressive non-native species.

Green Turtle

Diving the Marine World Heritage Sites

Forty-five World Heritage Sites – places of “outstanding cultural or natural value” – are located in marine areas. And many are also fabulous diving spots. Jointly, marine World Heritage sites comprise one third of the planet’s marine protected areas, in 34 countries. They are designated by UNESCO, the United Nations Educational, Scientific and Cultural Organization.

The first marine Heritage Site to be listed was the Galapagos Islands, in 1978. In the Pacific Ocean some 1,000 km from the South American continent, these 19 islands and the surrounding marine reserve have been called a unique living museum and showcase of evolution. Situated at the confluence of three ocean currents, the Galapagos are a melting pot of marine species.

Next listing was Australia’s Great Barrier Reef. It contains the world’s largest collection of coral reefs, with 400 types of coral, 1500 species of fish and 4000 types of mollusc.

Dugong or Sea Cow

Australia has the most Marine World Heritage sites of any country: five. Ningaloo Coast was inscribed most recently in June 2011. Ningaloo, in Western Australia, is famous for its whale sharks. Also on the West coast is Shark Bay. This has three exceptional natural features: its vast sea-grass beds, which are the largest and richest in the world; its dugong (sea cow) population; and its stromatolites. Stromatolites are rock like structures built by microbes, similarly to how corals build reefs. Shark’s Bay stromatolites are 2000 to 3000 years old, but stromatolites have been being built for 3.5 billion years. Shark Bay is also home to five species of endangered mammals.

Further north is the Philippines’ Tubbataha Reefs Natural Park. In the middle of the Sulu Sea, Tubbataha is 128 km from inhabited islands and is dived by liveaboard from March to June. The site comprises pristine coral reef with perpendicular walls, extensive lagoons and two coral atolls.

Another fantastic diving area is the French Pacific Ocean archipelago of New Caledonia. The Lagoons provide habitat to a number of emblematic or threatened marine species such as turtles, whales and dugongs whose population here is the third largest in the world.

Dolphin

Moving to the northern hemisphere, Cocos Island National Park, 550 km off the Pacific coast of Costa Rica, is the only island in the tropical eastern Pacific with a tropical rainforest. The underwater world of the national park is one of the best places in the world to view large pelagic species such as sharks, rays, tuna and dolphins. Also listed in Costa Rica is Guanacaste.

whaleshark

Colombia boasts the Malpelo Fauna and Flora Sanctuary. This vast marine park, the largest no-fishing zone in the Eastern Tropical Pacific, provides a critical habitat for internationally threatened marine species, and is a major source of nutrients resulting in large aggregations of marine biodiversity. It is in particular a ‘reservoir’ for sharks, giant grouper and billfish and is one of the few places in the world where sightings of the short-nosed ragged-toothed shark, a deepwater shark, have been confirmed. Widely recognized as one of the top diving sites in the world, due to the presence of steep walls and caves of outstanding natural beauty, these deep waters support important populations of large predators and pelagic species (e.g. aggregations of over 200 hammerhead sharks and over 1,000 silky sharks, whale sharks and tuna have been recorded) in an undisturbed environment where they maintain natural behavioural patterns.

Finally, Europe also has diveable Marine World Heritage Sites, notably Saint Kilda in Scotland with its oceanic blue water and visibility. The only dive site in Britain which is outside the green coastal waters.

Further Reading:

World Heritage Marine Programme

Barnacle Dinner in the Galapagos

The barnacle, a key thread in the marine food web, was thought to be missing along rocky coasts dominated by upwellings. Now a research team headed by Brown University marine ecologist Jon Witman has found the opposite to be true: Barnacle populations thrive in vertical upwelling zones in moderately deep waters in the Galapagos Islands.

Working at an expansive range of underwater sites in the Galapagos, marine ecologist Jon Witman and his team found that at two sub-tidal depths, barnacle larvae had latched onto rock walls, despite the vertical currents. In fact, the stronger the vertical current, the more likely the barnacles would colonize a rocky surface.

The researchers also documented the presence of whelks and hogfish, which feast on barnacles. This predator-prey relationship shows that vertical upwelling zones are “much more dynamic ecosystems in terms of marine organisms than previously believed,” Witman said.

Scientists who study coastal marine communities had assumed that prey species such as barnacles and mussels would be largely absent in vertical upwelling areas, since the larvae, which float freely in the water as they seek a surface to attach to, would more likely be swept away in the coast-to-offshore currents. Studies of the near-surface layer of the water in rocky tidal zones confirmed that thinking. But the field work by Witman and his group, in deeper water than previous studies, told a different tale: Few barnacles were found on the plates in the weak upwelling zones, while plates at the strong upwelling sites were teeming with the crustaceans. Flourishing barnacle communities were found at both the 6-meter and 15-meter stations, the researchers reported.

The scientists think the free-floating larvae thrive in the vertical-current zones because they are constantly being bounced against the rocky walls and eventually find a tranquil spot in micro crevices in the rock to latch on to.

Further Reading
Coupling between subtidal prey and consumers along a mesoscale upwelling gradient in the Galápagos Islands. Jon D. Witman, Margarita Brandt, Franz Smith. Ecological Monographs 2010 80:1, 153-177
Brown University News, Barnacles Prefer Upwelling Currents, Enriching Food Chains in the Galapagos