NEWSLETTER
ST LAWRENCE VISION 2000
VOLUME 12– ISSUE 3 – SEPTEMBER 2001
Preceding issues

	SUMMARY
	Biodiversity The Atlantic Sturgeon is slowly yielding up the secrets of its movements in the St Lawrence
	Navigation The marine environment at your fingertips…thanks to the St Lawrence Observatory
	Human health Comparison of drinking water disinfection procedures and their effect on the health of babies in three Quebec municipalities
	News in brief

Le Fleuve is published jointly by St Lawrence Vision 2000 partners.

Co-ordination
Raymonde Goupil, Clément Dugas and Suzanne Bourget

Text
Gaétane Tardif, Environmental Consultant

Realization
Françoise Lapointe, Editor, SLV 2000

Translation from French to English
PWGSC–Translation Bureau

This Newsletter is also available in PDF format.

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The Atlantic Sturgeon is slowly yielding up the secrets of its movements in the St Lawrence [Atlantic sturgeon] The body of the Atlantic Sturgeon is covered by five rows of protective bony plates. It is the largest freshwater fish found in Quebec or anywhere on the eastern seaboard of North America. Visible here on the dorsal fin is the radio tag used to monitor the fish’s movements for the purposes of the study. (Photo: François Caron, Société de la faune et des parcs du Québec)

IN TUNE Atlantic Sturgeon: new knowledge has made it possible to improve management of the Atlantic Sturgeon, a vulnerable species in Quebec waters. St Lawrence Observatory (OSL): a scientific portal devoted to the exchange of data on and the development of the St Lawrence, a vast natural laboratory. Though two studies comparing water disinfection procedures and their effect on babies’ health were reassuring, further studies have been recommended.

In spite of its large size, the Atlantic Sturgeon in the St Lawrence has remained highly elusive. After several years of research under Phases II and III of the St Lawrence Vision 2000 Action Plan (SLV 2000), biologists from the Société de la faune et des parcs du Québec have succeeded in identifying some of the species’ essential habitat. This new knowledge has made it possible to improve management of the Atlantic Sturgeon, a vulnerable species in Quebec waters.

The Atlantic Sturgeon is found only on the east coast of North America, and its northernmost population is in the St Lawrence. It is subject to a variety of pressures: overfishing, pollution, and habitat loss as a result of dredging and damming, so that it is now found in only 25 of the 40 or so watercourses that it used to inhabit, and it almost completely disappeared from the St Lawrence in the 1970s.

The Atlantic Sturgeon spends most of its life in salt water, but migrates to fresh water to breed. Thus, the biologists of the Société first spent a decade working on the St Lawrence’s tributaries to locate and characterize the breeding grounds of the sturgeon population.

Since their searches of the tributaries proved fruitless, the biologists set their nets in the St Lawrence itself, between the western tip of Île d’Orléans and Portneuf in the summer of 1997. Thirteen breeding males were taken near Portneuf, suggesting that spawning grounds may lie close at hand. On the basis of this information, the biologists applied a strategy: by following the movements of these specimens, they might be able to pinpoint their preferred habitat.

Close on the trail in the St Lawrence

In 1998, at the start of Phase III of SLV 2000, a five-year research project was launched to locate areas where adult surgeon congregate, in particular breeding and feeding grounds. Nets were again set at Portneuf, but this time the adults taken were tagged with radio transmitters, attached at the base of the dorsal fin, so that their movements in the River could be monitored.

Most of the sturgeon tagged in fresh water were male, and only one mature female was tagged during the summer of 1998. This scarcity of females in the catches may be due to the fish’s life cycle and the different behaviour of the females during the spawning season. Males reach breeding age earlier than females and breed more often. They also arrive on the breeding grounds earlier and stay longer, whereas the females make only very short forays into fresh water, just long enough to lay their eggs, which takes only a few hours or a few days at most. As the nets were moved to brackish waters, the proportion of females taken increased.

Thus, over a three-year period, the research team tracked the movements of 69 Atlantic Sturgeon, including 21 females. To do so, they used a boat and a submersible receiver to register the presence of any tagged sturgeon within a radius of one kilometre. A fixed tracking station was also installed at the end of the Irving jetty (about one kilometre downstream from the Quebec Bridge) and now continuously monitors the passage of any sturgeon heading for the spawning grounds.

Biologists find several schooling areas

Six sites where adult Atlantic Sturgeon gather have so far been located. Three of these are in fresh water and are believed to be breeding grounds: the Richelieu Rapids, upstream from Portneuf, discovered in 1997; a section of the River off St Antoine de Tilly; and the mouth of the Chaudière River. Since the breeding grounds of most Atlantic Sturgeon stocks throughout the species’ range remain unknown, this discovery delighted biologists.

Atlantic Sturgeon do not feed while migrating to the spawning grounds, nor during spawning. Monitoring of their movements as they leave the spawning grounds has made it possible to locate three feeding areas. Initially, it was thought that these would all be in brackish waters, as was the case of the site located north of Île aux Grues and another off Sault au Cochon. Surprisingly, though, the third feeding area was in fresh water: the mouth of the St Charles River, right in Quebec harbour. Many sturgeon stop there on the way from the spawning grounds to saltier habitat to take advantage of the rich supply of invertebrates.

The monitoring of tagged specimens has also helped determine the period of the summer most conducive to breeding. In the St Lawrence, this seems to occur between late June and mid July, when the water temperature ranges between 15° and 23°C. Various other characteristics of the species have been determined, among them the weight, length, age and sex of breeding specimens. It takes males at least 16 years to reach breeding age and females even longer, and rather than breeding every year like almost all other fish, the males breed only every third of fourth year and the females at even longer intervals.

As well as yielding information on where sturgeon congregate and what they do there, the research has shed light on the migratory movements of the species. On average, sturgeon cover 11.3 km per day, but the maximum daily distance recorded is 64.8 km, eloquent testimony to the Atlantic Sturgeon’s ability to cover long distances in the St Lawrence in a short time.

There are two sturgeon species found in Quebec: the Lake Sturgeon, found exclusively in fresh water in the St Lawrence and in a number of large lakes in western and north-western Quebec, and the Atlantic Sturgeon, which spawns in the River but spends most of its life in brackish or salt water. Here, Bruno Baillargeon, wildlife technician with the Wildlife Research Branch of the Société de la faune et des parcs du Québec, stands near the largest female taken in the summer of 2000. (Photo : Daniel Hatin, Société de la faune et des parcs du Québec)

New management based on better knowledge

Thirty-five commercial fishermen operating between Quebec City and Rivière du Loup take nearly 6,000 sturgeon a year. How is it that breeding specimens have never been found in catches? The study has shown that older specimens dwell in the deeper parts of the St Lawrence, especially in the channels and trenches, and since the fishermen set their nets in shallower water, they take only fish between the ages of 4 and 20 years and not yet sexually mature.

According to François Caron, biologist with the Société de la faune et des parcs du Québec, our ignorance of the Atlantic Sturgeon’s biology and habitat has made sound management difficult, but the data that have now been gathered will enable us to implement improved management measures. For example, schooling areas can be protected. He explains that in the past such operations as dredging and spoil dumping may have compromised the integrity of essential sturgeon habitat simply because we knew so little about it; now, though, the knowledge we have gained will enable managers to make more informed decisions on where to authorize the dumping of spoil from the dredging of harbours and the shipping channel. Moreover, the SLV 2000 Biodiversity and Shipping consultative committees are currently working together on a wide-ranging study of this issue, and some schooling areas may be closed to commercial operations while breeders are present, thus protecting those individuals on which the future of the St Lawrence population depends.

What is certain is that the Atlantic Sturgeon has not yet yielded up all its secrets. Biologists now plan to pinpoint breeding areas more precisely, since sturgeon cover relatively large distances, even in fresh water. We would like to determine the breeding success rate and find the preferred habitat of young sturgeon leaving the place where they hatched.

For information:

François Caron, biologist
Wildlife Research Branch
Société de la faune et des parcs du Québec
Telephone: (418) 521-3955, local 4377
E-mail: francois.caron@fapaq.gouv.qc.ca

Source:

HATIN, D., and F. CARON. Pending. Déplacements et caractéristiques des esturgeons noirs (Acipenser oxyrinchus) adultes dans l'estuaire du fleuve Saint-Laurent en 1998 et 1999, (Movements and characteristics of adult Atlantic Sturgeon in the St Lawrence estuary in 1998 and 1999), Société de la faune et des parcs du Québec, Wildlife Research Branch.

The purpose of this newsletter is to provide recent information on projects and activities surrounding the implementation of the St Lawrence Vision 2000 Action Plan.