Scuba-diver scientists from the U.S. Geological Survey, with support teams from the U.S. Environmental Protection Agency, the Lower Elwha Klallam Tribe, and Washington Sea Grant, are returning to the mouth of Washington’s Elwha River this week to explore and catalogue the effect of released sediment on marine life following the nation’s largest dam removal effort.

The underwater survey is taking place downstream of the Elwha and Glines Canyon Dams, which are nearing the one-year anniversary of the start of their removal, a gradual process that officials expect to be finished in 2013. The dive survey is helping scientists understand how underwater plant and animal life react and adapt to the downstream effects of dam removal and providing scientists a more detailed and complete picture of the ecological restoration.

“For nearly 100 years, sediment delivery to the lower reaches of the Elwha River and its mouth has been starved, with that material accumulating behind dams, affecting both the form of the beach and the nearshore marine communities,” said USGS Director Marcia McNutt. “With the recent initiation of dam removal, the sediment supply to the coast has literally gone from famine to feast, presenting a rare scientific opportunity to document ecosystem response to a large sediment pulse and the gradual recovery to the natural, pre-dam state.”

Scientists expect dam removal to cause short-term adverse effects to marine life, followed by large-scale ecosystem resurgence once the river’s sediment load returns to a more normal state.

The dive teams established and surveyed marked transects spread throughout the area around the Elwha River mouth, as well as at reference sites far from the Elwha River mouth that were installed last summer before the dam removal process began. These same strips of seafloor will continue to be monitored during and after dam removal to see how fish, kelp, and invertebrate populations respond to changes in deposited and suspended sediments.

“Research gained in this project will be vital to EPA’s Puget Sound Initiative and will inform future dam removals,” said Kate Kelly, Director of EPA’s Ecosystem, Tribal and Public Affairs office in Seattle. “With this removal well underway, it’s time to begin analyzing the effect of the recent sediment plume and its impact on underwater health.”

More than 24 million cubic yards of sediment, enough to fill an NFL football stadium eight times, had accumulated behind the Elwha River dams. USGS scientists estimate that as of July, about 400,000 cubic yards of sediment has been released, with the majority of sediment expected to be released when the upstream Glines Canyon Dam is completely decommissioned.

As the dams are removed, sediment is carried downstream, changing the structure of the riverbed. The estuary complex where the river meets the Strait of Juan de Fuca and the nearshore seabed is also being impacted. USGS studies indicate that high concentrations of sediment will create turbid conditions in the river and coastal waters for about five years, a process scientists are monitoring.

The Elwha River Restoration Project, created by an Act of Congress in 1992, aims at the full restoration of the Elwha River ecosystem and its native anadromous fisheries.

written by Ecosystem and Ecography

Must we triage the world’s biodiversity? An ecologist asks if it’s worth trying to save a species caught in an ‘extinction vortex,’ in this case monk seals, by culling Galapagos sharks that have their own survival issues.

The “extinction vortex” is all too familiar in the world of endangered species: Extremely small populations often become vulnerable to new threats, precipitating a downward spiral toward extinction. But in a world of limited resources, I wonder about society’s obligation to intervene where there is little chance for reversing downward trends. A case in point is the critically endangered monk seal, which is declining toward extinction in one of the most pristine marine wilderness areas on earth.

The Papahānaumokuākea Marine National Monument in the northwest Hawaiian Islands is the largest marine protected area in the US. The monument, established in 2006 by President George W. Bush, has been heralded as a conservation success and the reserve teems with a diversity of marine organisms.

With this intact ecosystem has come the recovery of top predators—sharks. But in an unintended consequence, shark predation has been implicated as a primary cause of the decline of the monk seal.

Most of the remaining 1,000 Hawaiian monk seals live in the monument, and their numbers are in precipitous decline. Their populations became so small that sex ratios skewed towards males, creating social dysfunction and male aggression. That aggression seemed to peak in 1997, which was also the first time researchers observed sharks eating an intriguing new source of food that they continue to rely on today—drowned seal pups in the water.

Should humans intervene to reverse this extinction vortex and to help monk seals recover within their “restored” habitat? This raises a clear question about “conservation triage”: Do we want an ecosystem with a viable population of monk seals, or do we want to maintain the virtues of having a marine ecosystem with a full complement of apex predators?

In its answer to that question, the National Marine Fisheries Service is proposing to cull Galapagos sharks in areas of the monument with a particular problem, such as the French Frigate Shoals. The rationale is that removing a few “nuisance” sharks who have learned to hunt for monk seals will reduce early mortality of monk seals, which is very high in their first two years of life. The hope is that this would stabilize monk seal populations—and still maintain a viable shark population and a diverse community structure within the monument.

Is it scientifically and ethically defensible to kill a few sharks to save monk seals from extinction?

Without intervention, monk seals will likely become extinct before my children grow up to see them. On the other hand, there is no guarantee that culling sharks will lead to the seals’ recovery. A sustained program to remove sharks likely will reduce their take in localized areas, perhaps enough for juvenile monk seals to survive. But, there also is a chance that culling will hurt the viability of the shark population, which is already suffering globally through bycatch.

While scientists hypothesize that only a few sharks&mdashthose “nuisance animals”—are eating monk seals, supporting data are sparse, and other species such as tiger sharks are known to prey upon monk seals. This build-up of predators in the Northwestern Hawaiian Islands and the complexity of the ecosystem may make controlling shark predation impractical.

A careful evaluation of the costs and benefits of different management options (e.g., shark predation mitigation, translocation or captive breeding of monk seals) is needed to identify the greatest likelihood of success given societal preferences, logistical, and financial constraints.

As a society, are we prepared to accept that our proverbial Noah’s ark is perhaps not large enough to bring all of the world’s species into the future of our children? More importantly, do we have the proper ethical code in place to justly triage the planet’s declining biodiversity?

written by Ecosystem and Ecography

One hundred and fifty years ago, the British colonial administration in India proposed a shipping canal project that would allow cargo vessels, commercial liners and large ships to cut through the Gulf of Mannar Marine National Park in the Palk Straits between India and Sri Lanka, thereby slashing 424 nautical miles (about 780 kilometres) off the traditional shipping route around Sri Lanka to the Far East.

Opposition based on ecological concerns, fear of heightened seismic activity in the region and cultural sensitivities stalled the project for over a century but it forced its way back onto the negotiating table.

The Indian Prime Minister finally inaugurated the Sethusamudram Shipping Canal Project (SSSCP) on Jul. 2, 2005 but it was contested in the Indian Supreme Court, which stayed the project in September 2007.

Earlier this month an expert committee headed by R.K. Pachauri, chairman of The Energy Research Institute (TERI), submitted a report to the Indian Supreme Court stating that alternative routes to the controversial SSSCP, which cuts through the historic Adam’s Bride in the Gulf of Mannar, are not viable.

The SSSCP will cleave through the protected Gulf of Mannar Marine National Park, allowing a shorter travel route for shipping tankers plying between the Middle East and the Far East through the Indian Ocean and the Bay of Bengal.

The area in white depicts the deep sea where no dredging is necessary for the shipping canal. The area in blue, south of the Adam’s Bridge, indicates the shallow waters of the Gulf of Mannar Marine National Park. Credit: Captain S. Viswakarma

It is estimated that ships from Europe and Africa sailing to the Far East may save up to 5000 dollars per voyage if they use the canal.

The shorter shipping canal is also expected to give a tremendous economic boost to small Indian ports like Tuticorin, Kanya Kumari, Nagapatnam, Ennore, Cuddalore, Thondi and the temple town of Rameshwaram.

Risks abound

More than 2000 ships will transit through the canal carrying more than 15 million tonnes of crude oil, and other internationally tradable commodities, leaving the marine park very vulnerable to oil spills.

“An important aspect of risk management relates to the possibility of oil spills which, even with the most stringent measures and precautions, would be difficult to rule out completely. The study clearly finds that oil spills could possibly pose a risk to the biosphere reserve, which needs to be protected under all conditions,” the expert committee report stated.

Staunch opponents of the project claim that dredging can destroy the shallow sea floor, disturb the shoal ecosystem, and ruin the habitat of rare and endangered species. The ecosystem in the National Park is comprised of shifting sand banks under the rocks, shoals and underwater reefs, all of which could be destroyed by the shipping canal.

In addition, there are no guarantees that the canal will survive another tsunami that could easily be triggered off the volatile coast of Sumatra, Indonesia.

Adam’s Bridge also has cultural and religious value, as Hindus believe that Lord Rama crossed it to rescue his kidnapped wife, Sita, from Ravanna in Sri Lanka. The so-called ‘bridge’ is comprised of a chain of limestone sand banks connecting India and Sri Lanka and has, over the years, been submerged by rising seas.

written by Ecosystem and Ecography