Margined madtom (Noturus insignis) COSEWIC assessment and status report 2012: chapter 4

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Distribution

NorthAmerican Range

The distribution of the margined madtom throughout North America was described in the 1990 COSEWIC report (Goodchild 1990). The native U.S. range of the margined madtom includes the Finger Lakes region south towards the Appalachian Highlands and includes most of the Atlantic coastal streams from New York to Georgia (Figure 2). Individuals have also been found in New Hampshire and Michigan (Lee et al. 1980). In Pennsylvania, the margined madtom is the most commonly captured madtom species throughout the Susquehanna, Potomac, and Delaware River drainages (Gutowski and Raesly 1993).

CanadianRange

Canadian populations of the margined madtom are at the northernmost limit of the species’ natural range. The margined madtom has a disjunct distribution in Canada, restricted to a few streams, rivers, and lakes in Ontario and Quebec (Figure 3).  The first reported Canadian specimens were captured in Quebec, in a stream draining Lac à la Loutre to Lac Lapêche in Gatineau Park, 45 km northwest of Ottawa. Four specimens were captured in August 1971 and 25 more specimens were captured in November of that same year (Rubec and Coad 1974). These specimens are catalogued in the Canadian Museum of Nature (CMN), in Ottawa [NMC 73-0142, NMC 74-0004]. Elsewhere in Quebec, on 1 September 1982, two margined madtoms were captured in Rivière Lapêche, Saint-Louis-de-Masham, Gatineau County [NMC82-0572] and another specimen was captured 19 July 1983 [NMC83-0S35].

Since the original status report, several margined madtom specimens were captured from new locations in Quebec. Chabot and Caron (1996) reported that two margined madtom specimens were captured along the Quebec side of the Ottawa River, between Hull and Lochaber, Hull County and one specimen was captured between Lochaber and Montebello, Papineau County in 1996. In the Gatineau River, 12 km upstream from the confluence with the Ottawa River, Hull County, two margined madtom were captured in May and one in June 1999 by a joint project between the University of Ottawa and the Société de la faune et des parcs du Québec (SFPQ) (Richard Pariseau, SFPQ, personal communication). During 2000 or 2001, an unknown number of margined madtom specimens were collected from the Cole Lake area in Buckingham, Quebec (Michel Lepage, SFPQ, personal communication).

The first specimen found in Ontario was collected in May 1976 by the Ontario Ministry of Natural Resources (OMNR), in the Fall River, Lanark County, 85 km southwest of Ottawa. An additional 14 specimens were captured a month later at the same location. These specimens are catalogued in the Royal Ontario Museum (ROM) in Toronto [ROM 32581].

Since the original status report (Goodchild 1990), several margined madtoms have been collected from new locations in Ontario. In Bolton Creek, Hamlet of Fallbrook, Lanark County, Ontario, on 8 September 1990, one specimen was collected by OMNR [ROM 66063]. On 4 September 1997, one margined madtom was collected from the Mississippi River, Hamlet of Playfairville, Lanark County, Ontario, by the OMNR [ROM 70991]. An additional specimen was captured by the OMNR in the Mississippi River, 22 km downstream from Playfairville, in Innisville, Lanark County, Ontario in September 2000 (Shaun Thompson, OMNR, personal communication). The Fall River, Bolton Creek and Mississippi River are all interconnected and the sampling sites in this area are in relatively close proximity, within 30 km of each other.

Elsewhere in Ontario, a margined madtom was first captured in Lake Joseph, Muskoka District, Ontario, by OMNR 17 October 1988, and the following October, another specimen was captured at the same location [ROM 55839; 58161]. One margined madtom was captured in Lake Muskoka by OMNR in 1993 [ROM 68167] and one specimen was captured by OMNR in 1996 in Lake Rosseau (Alan Dextrase, OMNR, personal communication).

The disjunct distribution of the margined madtom has led to skepticism as to whether the margined madtom is a native or an introduced species. Goodchild (1990) discussed both hypotheses in the original status report and the consensus of the author and the Committee at the 1989 assessment meeting was that it was a native species. Noturus insignus may have immigrated through interconnecting post-glacial lakes 8 000 – 10 000 years ago. Margined madtom is known from several lakes, rivers and streams in separate locations in Muskoka, Lanark, Hull, and Papineau counties. Similar disjunct populations are known in the U.S. from New York State and New Hampshire. McAllister (1987) reported that the Canadian capture site in Gatineau Park, Quebec is only 130 km from the margined madtom occurrence in western New York. The closeness of this record makes it plausible that the Canadian occurrence is natural and not due to introductions.

The alternative hypothesis is that the distribution of margined madtom has expanded into Canada as a result of its use as baitfish. This fish is a popular baitfish in the United States and survives transportation well (Coad 1986). There is evidence of introduced margined madtom populations in Clark Lake, Gogebic County, Michigan [UMMZ 186551] and Merrimack River of New Hampshire (Goodchild 1990).

Since the original status report, several publications have commented on the status of the margined madtom in Canada. Crossman (1991) lists the margined madtom as a non-native species introduced via bait bucket. Mandrak and Crossman (1992) list the margined madtom as an introduced species in their checklist of Ontario freshwater fishes. Litvak and Mandrak (1993) identify the margined madtom as one of 4 exotic species that have been introduced to Ontario through use as bait. Bernatchez and Giroux (2000) were undecided as to the native status of the species.

Regardless of the restrictions on the use of madtoms as baitfish, the new areas of capture are popular angling spots making it difficult to determine if the species is introduced or native. Genetic studies would assist in distinguishing between recent introductions (no genetic drift) and colonized (genetic drift) populations. In the absence of genetic studies and invoking the precautionary principle, it is still assumed that the margined madtom is a native species.