Section 3 – Science at Work

Science Feature Stories

Every month, DFO Science presents new feature stories about its work. The following selections are from some of the most popular stories of 2005-06. Readers can subscribe to the stories, or visit the website to read more about oceanography, marine and freshwater biodiversity, hydrography, aquaculture, marine mammals, genomics, and the science and technology that is changing our understanding of the aquatic world.

Forecasting the State of the Ocean

If the land rose and fell with the wind and shifted around daily, one might hesitate to go to work in the morning. But fishermen, sailors, oil explorers, search and rescue specialists, and other seafarers must cope daily with a highly changeable ocean.

More predictability would benefit industry, science, and humanity at large. Dr. Fraser Davidson, a physical oceanographer with the Department of Fisheries and Oceans (DFO) in St. John's, Newfoundland and Labrador, is spearheading an effort to improve ocean forecasting for a major swath of the northwest Atlantic, including the Newfoundland and Labrador shelves.

Biological Station Keeps Innovating in Aquaculture

Atlantic Canada's oldest fisheries-research station is helping to shape a new industry. The St. Andrews Biological Station in Passamaquoddy Bay, New Brunswick, on the Bay of Fundy, began groundbreaking work on salmon aquaculture in the 1970's. Among highlights in following years, researchers developed new methods for farming groundfish such as haddock and halibut. Now, they are looking into the future with polyculture, in which different forms of aquaculture reinforce one another.

Charting the World's Longest Coastline

Pleasure boaters, commercial fishermen, seafarers on Canadian ships and others from around the world, all depend on a warehouse near downtown Ottawa. From this chart distribution centre, the Canadian Hydrographic Service (CHS) supplies mariners with nearly a thousand different navigational charts, covering the world's longest coastline, almost a quarter-million kilometres, in all its sinuosities and with all the details of depths, buoys, lighthouses, and hazards to navigation. CHS charts also cover the Great Lakes and other major lakes and rivers.

Does Seismic Exploration Harm Whales and Fish?

Every swimmer learns the startling efficiency of underwater sound propagation. When someone at a distance taps two rocks together, it seems to be happening next to your eardrums. Many marine creatures make and react to sounds. Whales in particular vocalize to sing, communicate, and navigate.

But what happens when man-made noises mix with those of the ocean? Millions of boat engines, the giant propellers of ships, military and commercial sonar equipment, coastal construction operations, and the drills of offshore oil rigs all pour sounds into the sea. And in recent decades, concern has mounted over oil exploration using seismic methods.

Experimental Lakes Solving Mercury Puzzles

What happens within lakes as human activities contaminate them, disrupt their surroundings, or otherwise change their environment? Laboratory experiments can suggest partial reactions, but never give the entire ecological picture. So in 1968, federal fisheries researchers got government approval to set aside, in the Pre-Cambrian shield country of northwestern Ontario, a network of lakes for environmental experiments. This was a world first, and it has yielded world benefits.

The Experimental Lakes Area (ELA) has, for example, proved how certain nutrients foster eutrophication, the over-enrichment of plankton and plant growth that consumes oxygen from lakes and shrinks their biodiversity. This led to bans on phosphorus in detergents, which helped clean up lakes in Canada and internationally. And the ELA's documentation of the alarming effects of acid rain on lake life helped create better controls on some sources of pollution.

Are Seal Herds Damaging Atlantic Fish Stocks?

Canada's northwest Atlantic holds the world's biggest populations of harp, hooded, and grey seals. Harp and hooded seals are subject to a centuries-old, now quota-controlled commercial hunt. After declines during the 18th and 19th centuries, herds have recovered to their highest abundance on record, while stocks of cod and other groundfish fell to their lowest, and still show little sign of recovery.

The Fisheries Resource Conservation Council (FRCC), an advisory group of university scientists, government and fishing-industry representatives, says that seal predation threatens the recovery of some groundfish stocks.

But how exactly do seals affect groundfish? Fisheries and Oceans Canada's Atlantic Seal Research Project has turned up significant new information through techniques old and new, some of it unprecedented and surprising, concerning populations, their habits and the extent of predation by harp, hooded and grey seals on Atlantic cod.

Fighting Invaders in the Gulf of St. Lawrence

Habitat biologists Nathalie Simard and Michel Gilbert usually researched waters of the Estuary and Gulf of St. Lawrence. Then they found themselves dropping plankton nets in a new location: the ballast tanks of a huge ore carrier plying between Europe and Quebec.

The sampling was part of the struggle to minimize the risk of non-indigenous species invading Canadian waters, via ballast water. In the Great Lakes alone, more than 160 alien organisms have taken hold. The notorious zebra mussel, perhaps transported from the Black Sea in ballast water, covers lakebeds, docks, and boat hulls like a living carpet, and has caused billions of dollars in damage.

For the most part, aquatic invaders are difficult to treat and practically impossible to eradicate. Prevention is the best hope, to keep them out or at least delay their spread, while improving knowledge and searching out methods of control.

Researching the Future of Snow Crab

Safeguarding the snow crab harvest is of vital interest to the thousands of people whose livelihoods depend on it.

For this young fishery, which began about four decades ago, many regulations apply, including quotas and seasons. But one idea in particular has shaped management: protecting female crab.

Adult females are smaller than males. The Department of Fisheries and Oceans (DFO) sets size limits and requires mesh sizes in crab traps large enough to let most adult female crab escape. Fishermen must return any remaining females to sea alive.

Pacific Salmon Research: Facing the Climate Challenge

Climate change in this century may raise temperatures only a couple of degrees on Canada's west coast, but that will mean more than wearing lighter clothes. British Columbia could suffer worse floods, droughts, and forest fires. And far-reaching changes in the Pacific Ocean will affect both fish and people.

Fighting Invaders in the Gulf of the St. Lawrence: DFO scientist Chris McKindsey with the green alga known as oyster thief or dead man's fingers (Codium fragile). Photo Credit: Philippe Archambault

The west coast's foundation fish, Pacific salmon underlay the economy, art, and culture for First Nations. They provided the resources for a great commercial industry and growing sport fishery. But they may face major disruption from climate change.

Researcing the Future of Snow Crab: Snow crab is the foundation of Canada's valuable crab fishery. DFO scientist Bernard Sainte-Marie is conducting research to learn more about snow crab reproduction. Photo Credit: DFO

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