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

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COSEWIC
Executive Summary

Banded Killifish
Fundulus Diaphanus
(Newfoundland Population)

Species Information

The Banded Killifish, Fundulus diaphanus (Lesueur 1817) is a member of the family Fundulidae (Nelson 1994). This species is one of only two members of the Fundulus genus found in Newfoundland, the other being the mummichog, F. heteroclitus. The Banded Killifish is described as having olive colored sides with numerous vertical bands and a contrasting dark coloration across the dorsal region. The vertical bands give rise to the common name “Banded” Killifish.

 

Distribution

The Banded Killifish is found in southeastern North America from Montana east to the Maritimes and south to south Carolina. In Canada, it is widely distributed in the Maritimes (but only from a few sites in Newfoundland) and also in suitable habitat of the St. Lawrence River valley of Quebec, through the Great Lakes watershed of southern Ontario to Lake Superior (Scott and Crossman 1973). A disjunct population is also found in Manitoba (Stewart-Hay 1954).

There are 7 known populations of Banded Killifish on the island of Newfoundland. The majority of these populations are clustered on the south and western coasts of the province. One of the most recent records of this species, from Indian Bay watershed (Backup and Third Ponds) on the northeast coast of the island is further east than previous records for this species. Initially, Fundulus diaphanus was only recognized from the very southwestern corner of Newfoundland in the Stephenville Crossing area. From 1980-1990, in addition to the Indian Bay occurrence, new population records include Freshwater Pond and the Rush Ponds (Winterland) on the Burin Peninsula, Ramea Island off the south coast, Loch Leven, and First Pond in the Grand Bay West area, near Port aux Basques.

The status of this species in Canada was first considered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1989. Newfoundland populations were considered to be the biogeographically isolated from mainland populations and were assigned a status of Special Concern due to the limited area of occupancy, limitation of potential for range expansion and potential threats from logging and other activities leading to habitat degradation.

 

Habitat

Banded Killifish in Newfoundland depend on clear water, warm water temperatures for spawning, and dense submerged aquatic vegetation with a sandy or muddy substrate. This type of habitat is abundant throughout most watersheds in Newfoundland but the species is only found in a few of these watersheds. In addition, in watersheds where Banded Killifish occur and where there are many lakes with appropriate habitat areas, Fundulus diaphanus is often found only in very restricted areas within one or two lakes. Future research priorities should concentrate on habitat selection and use. Decline in this species in the future would likely be caused by habitat degradation and wetland drainage.

 

Biology

Newfoundland Banded Killifish grow to an average length of 73-92mm and live to a maximum of 3-4 years of age. Maturity is reached at an age of 1+ years and at a length of approximately 6cm. Banded Killifish practice external fertilization and females lay eggs equipped with adhesive threads that adhere to plants, leading to them being labeled plant-spawners. Spawning occurs in July and August at water temperatures of 19-24°C (Chippett In prep.).

 

Population Sizes and Trends

Fundulus diaphanus populations in Newfoundland occur over a wide range, but local populations are restricted to very confined regions within their respective watersheds. Banded Killifish populations in Newfoundland appear to be locally abundant in representative populations that were sampled. Although yearly data is not available, population estimates indicate that over 20 000 individuals exist in the Indian Bay watershed population on the northeast coast. Population estimates are not available for other populations.

 

Limiting Factors and Threats

Any disturbance, whether natural or anthropogenic, on the southwest coast of Newfoundland, could have a devastating impact on this species due to the cluster of populations in that region. However, direct threats are not perceived in this region at this time. However, forestry practices in the Indian Bay watershed may impact on the population in that area in the next few years as much of the forest in this area is scheduled to undergo some form of clear cutting.

Suitable habitat is present island-wide but inland areas are restricted from immigration of Banded Killifish by rivers with steep gradients and other barriers to inland migration.

 

Special Significance of the Species

Fundulus diaphanus is the only freshwater fish of special concern in Newfoundland and represents this species at the eastern extent of its range. Clustered in very localized regions of the watersheds in which they occur, Banded Killifish, which rely on the invertebrate community for food, clear water for prey selection, and dense stands of macrophytes for reproduction, are an easily studied indicator species candidate for various measures of ecosystem integrity. Banded Killifish are also important forage fish for brook trout, Atlantic salmon and American eels and form portions of the diet of various waterfowl.

 

Existing Protection or Other Status Designations

The Newfoundland populations of Banded Killifish are currently listed as a species of special concern by the Committee on the Status of Endangered Wildlife in Canada. In addition, Fundulus diaphanus is one of 20 species protected under the Newfoundland and Labrador provincial government’s Endangered Species Act passed in August 2002. Aside from this protection, the only other protection is made available through the Federal Fisheries Act. The population at Grand Bay West may be included in an ecological reserve being proposed by the Parks and Natural Areas division of the Government of Newfoundland and Labrador and the Rush Ponds population on the Burin Peninsula is an Eastern Habitat Joint Venture site.

 

Summary of Status Report

Banded Killifish populations in Newfoundland are very fragmented in nature. In spite of 7 known population locales, the area of occurrence of these populations is less than 200 km2. These populations, with the exception of the Indian Bay watershed population, are clustered in relative 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 three populations surveyed directly (Indian Bay, Loch Leven, and Freshwater Pond) indicate that the species is locally abundant but actual population estimates are only available for the Indian Bay population.

The other major limiting factor impacting F. diaphanus in Newfoundland is rivers with steep gradients and other obstructions to inland migration. Habitat, in terms of substrate type and aquatic vegetation, is abundant in central regions, but is likely inaccessible to Banded Killifish due to these difficult migration routes.

The obvious habitat requirements associated with Banded Killifish throughout North America are not limiting factors in Newfoundland. However, habitat selection and use is still not fully understood and warrant further study.