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COSEWIC Assessment and Update Status Report on the Banded Killifish, Newfoundland population in Canada

Summary of Status Report

The Newfoundland populations of Banded Killifish, Fundulus diaphanus, were designated as vulnerable (species of special concern) by the Committee on the Status of Endangered Wildlife in Canada in 1989 (Houston 1990). This updated report recommends that this species be evaluated based on the following conclusions.

Banded Killifish populations in Newfoundland are very restricted in nature. In spite of 7 known population locales, the area of occurrence of these populations is less than 200 km2. In addition, these populations, with the exception of the Indian Bay watershed population, are clustered in relatively close proximity on the southwestern portion of Newfoundland, maximizing the potential of natural disturbance, urban expansion, and industrial development, on 4 of the 7 recognized Newfoundland locales.

The most likely limiting factor impacting F. diaphanus in Newfoundland is rivers with steep gradients and other obstructions to migration. This geographic feature will restrict this species to the coastal regions where it has been discovered thus far and prevent dispersal throughout the central insular waters of Newfoundland. Therefore, although appropriate habitat is abundant in these regions, much of it is inaccessible to Banded Killifish due to difficult migration routes.

The obvious habitat requirements associated with Banded Killifish throughout North America, which include dense submerged aquatic vegetation, muddy or sandy substrates, and warm water temperatures for spawning, are not limiting factors in Newfoundland. However, even in coastal watersheds that include easily passable linkages between several lakes with much habitat as described previously, Banded Killifish still remain restricted in one “isolated” geographical pocket population and do not appear to spread throughout the entire system. More information is required on the strict parameters surrounding habitat selection and use and the dispersal of Banded Killifish throughout watersheds in Newfoundland and this should be a priority for any future research on this species in Newfoundland.