STATUS OF THE SPRING SPAWNING CISCO POPUL ATION (COREGONUS SP) AT LACDES ECORCES

Spring spawning is very rare in the genus Coregonus. Outside of the Gr eat Lakes, it is known in Canada only in Lake des Ecorces (Quebec), fo r a population possibly linked to the Coregonus artedi complex. This p opulation is distinguished from other local stocks by differences in m eristic and morphometric characters, including a marked difference in the number of gill rakers. The abundance of the population seems to ha ve remained the same since its discovery in 1981. However, Lake des Ec orces has been undergoing rapid eutrophication during the past twenty years, and general conditions will deteriorate if no action is taken. Spawning takes place in deep water, hence the sensitivity of the eggs to oxygen depletion and increased sedimentation. The Lake Cisco is a s pecies which is generally vulnerable to predation and to the deteriora tion of the quality of its habitat. Based on these observations and on the uniqueness of the population it appears that the Spring Cisco of Lake des Ecorces is a vulnerable population in Canada.