Home | Contact ST  

Follow ST

Marine Resources


May 2012 Issue

Ocean Acidification Linked to Hatchery's Larval Oyster Failure
Researchers have linked the collapse of oyster seed production at a commercial oyster hatchery in Oregon to an increase in ocean acidification, said a report published in April in Limnology and Oceanography. Larval growth at the hatchery declined to a level considered by the owners to be 'noneconomically viable."

The study found that increased seawater carbon dioxide (CO2) levels, resulting in more corrosive ocean water, inhibited the larval oysters from developing their shells and growing at a pace that would make commercial production cost-effective.

'This is one of the first times that we have been able to show how ocean acidification affects oyster larval development at a critical life stage,' said Burke Hales, an Oregon State University (OSU) chemical oceanographer and co-author of the paper. The owners of Whiskey Creek Shellfish Hatchery at Oregon's Netarts Bay experienced a decline in oyster seed production several years ago. Alan Barton, who works at the hatchery and is a co-author of study, was able to eliminate those potential causes and shifted his focus to ocean acidification. Barton sent samples to OSU and to NOAA's Pacific Marine Environmental Laboratory.

The results clearly linked the production failures to the CO2 levels in the water in which the larval oysters were spawned and spent their first 24 hours, which is a critical time when the oysters develop their shells.

The researchers believe that hatchery operators may be able to adapt to take advantage of periods when water quality is at its highest, such as seasonal upwelling, the tidal cycle and even times of day. The researchers also found larval oysters showed a delayed response to the water chemistry, which may cast new light on other experiments looking at the impacts of ocean acidification on shellfish.

App Created to Help Mariners Avoid Endangered Right Whales
Whale Alert, a free app launched in April for iPhone and iPad, is designed to warn mariners along the U.S. East Coast when entering areas where there is high risk of collision with endangered North Atlantic right whales.

Developed by EarthNC (Delray Beach, Florida), the app uses GPS, automatic identification system (AIS), Internet and digital nautical chart technologies to alert mariners to NOAA's right whale conservation measures that are active in their immediate vicinity.

The app displays data from near-real-time acoustic buoys that listen for right whale calls, showing the whale's presence to captains transiting the shipping lanes in and around Stellwagen Bank National Marine Sanctuary.

North Atlantic right whales, which live along North America's east coast from Nova Scotia to Florida, are estimated to have a population of approximately 350 to 550. Collision with ships is a leading cause of right whale death, said the organizations that collaborated on developing the app and system.

The buoys detect right whale vocalizations within a 5-mile radius. Once a buoy picks up a whale call, the signal is passed via satellite to Cornell University's Bioacoustics Research Program, where a technician confirms whether it is a right whale. If confirmed, Cornell will trigger a message via the AIS.

The transmitted AIS message is decoded by the app, allowing the Whale Alert buoy icon to turn yellow on the map. The Whale Alert app automatically renders the color-coded buoys in the proper geolocation over NOAA raster charts. Vessel operators using the Whale Alert app offshore can then slow down and post a lookout to avoid collision. If 24 hours pass without an additional confirmed detection, the buoy icon returns to green.

US, Russia to Conduct Aerial Surveys of Ice-Associated Seals
A U.S.-Russia team of researchers has designed a large-scale aerial survey using advanced imaging systems and statistical techniques to provide the first comprehensive estimates of abundance for ice-associated seals. The survey is to begin mid-April and wrap up in May and will include nearly 19,000 nautical miles of track lines over U.S. waters and 11,000 nautical miles over Russian waters.

This effort, supported by NOAA, the Bureau of Ocean Energy Management and Russian institutions, is the largest survey to estimate the abundance of these seal species. A second survey is planned during the same time in 2013.

Knowledge about ice-associated seals is sparse. Studying seals in the Bering Sea and Arctic waters poses many challenges that limit the ability of scientists to learn about these animals. Aerial surveys allow scientists to study ice-associated seals while covering large areas in a relatively short amount of time. The results of this study will be used to identify, evaluate and resolve conservation concerns under the Marine Mammal Protection Act, as well as assess the risk posed by loss of sea-ice habitat.

Gulf Residents Say Spill Changed Their Environmental Views
University of New Hampshire researchers have found that about one-fourth of Louisiana and Florida residents affected by the BP Deepwater Horizon oil spill said they have changed their views on other environmental issues as a result of the accident. This proportion rose to 35 percent among those most affected economically by the spill.

The results, published in April in Social Science Quarterly, are based on telephone surveys of 2,023 Gulf Coast residents conducted after the oil spill, split almost evenly between people in Louisiana's Plaquemines and Terre'bonne parishes and Florida's Bay, Gulf and Franklin counties. Most interviews took place between July and September 2010.

Louisiana residents more often reported that the spill had major effects on them and their families. They also saw more serious consequences from extreme weather and greater threats from sea level rise caused by climate change.

However, they were less likely than Florida residents to favor a moratorium on deepwater drilling, increased use of alternative energy or conservation of natural resources.


-back to top-

Sea Technology is read worldwide in more than 110 countries by management, engineers, scientists and technical personnel working in industry, government and educational research institutions. Readers are involved with oceanographic research, fisheries management, offshore oil and gas exploration and production, undersea defense including antisubmarine warfare, ocean mining and commercial diving.