Scientists of the Research Chair in exploited species of the Universite du Quebec a Chicoutimi (UQAC) have made further hauls smelt larvae in the north of Lac Saint-Jean, to document the production capacity of this area more precisely in the construction of artificial spawning grounds in the winter of 2017.
The team of Professor Pascal Sirois has seen fit to enjoy the postponement of a year of construction of rocky islets to improve its database of the area selected for the project of spawning grounds. These figures take all their importance when the islets have been erected and the rainbow smelt, rainbow, primary power source for landlocked salmon, or have not used these structures for breeding.
“The trawling we have made further confirm the presence of smelt larvae in the area of the island aux Pins just south of the mouth of the Mistassini River. It is not possible to specify the importance of the number of larvae, but the sector is still productive, “says biologist Pascal Sirois.
The decision to install the mounds of rocks in the area of Lake Saint-Jean stems trawling smelt have demonstrated the presence of small fish in the area during periods when the rainbow smelt was at its lowest . Project officials have concluded that the presence of stem and other pieces of wood on the sandy bottom offered smelt egg stronger structures to hook and hatch the sand.
“It was therefore an additional year of data confirming that in addition the area is interesting. We will have readings for a year without structure that will allow for comparisons. We also conducted trawls which confirmed the presence of larvae in the area of the mouth of the Peribonka River, “says the biologist.
The presence of smelt larvae in both areas tends to confirm the hypothesis of scientists to the effect that there is reproduction of smelt in several areas of Lake Saint-Jean when stocks are rising. This year, the indicators confirm that we are in a growth cycle.
Scientific knowledge, however, not possible to ascertain the exact reproduction sites. This is the case of the Péribonka River. Hauls of the past show that smelt spawns in the river or its mouth, but the precise location is not identified as is the case for Pine Island.
Students will conduct laboratory tests on smelt larvae collected during trawling. The evidence found on the specimens will help determine the age of the larva and thus to obtain a clearer picture of its outbreak.
Smelt swim on the surface and drop the eggs into the bottom of Lake Saint-Jean. The eggs cling mostly to sand grains and are therefore more at risk. The development of spawning grounds is to have mounds of rocks to allow the eggs clinging to the stone. According to Pascal Sirois, an increase of only a few percentage points of hatchability would have major positive implications for the stabilization of smelt stocks and limit the differences in the cycles of abundance and scarcity of landlocked salmon.