Striped bass (Morone saxatilis) COSEWIC assessment and status report: chapter 4

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Distribution

Global range

The natural range of the striped bass extends along the Atlantic coast of North America from the St. Lawrence Estuary to the St. Johns River in northern Florida. Native striped bass populations have existed in the tributaries of the Gulf of Mexico, from the Suwannee River in northwestern Florida to Lake Pontchartrain in Louisiana (Lee et al. 1980; Bain and Bain 1982).

The species was introduced into the estuary of the Sacramento and San Joaquin rivers in California in 1879 (Bonn et al. 1976). From this initial group, populations gradually became established in rivers on the U.S. Pacific coast (Hart 1973; Lee et al. 1980; Setzler et al. 1980).

The species can live and, in some cases, complete its life cycle in freshwater (Scruggs 1957). It has been introduced, as a sport fishery species, into several lakes and reservoirs in the United States, Russia, France and Portugal, with varying success (Lee et al. 1980; Setzler et al. 1980). At some locations, naturally reproducing populations have become established. Elsewhere, bass grows well but cannot reproduce. Ongoing stocking programs are therefore required to support fishing activity (Lee et al. 1980).

Canadian range

This status report covers the only known native striped bass populations, which spawned in five rivers in eastern Canada: the St. Lawrence, Miramichi, Shubenacadie, Annapolis and Saint John rivers (Figure 2). Catches of immature or adult striped bass have been reported at several locations in the Maritime provinces (Table 1). However, the presence of these individuals does not necessarily mean that distinct local populations occur and reproduce at each location. The presence of eggs or larvae is the most common indicator of spawning.

Figure 2.  Location of five rivers in Eastern Canadathat have supported spawning striped bass populations. 

The filled-in circles indicate extant populations and the open circles indicate rivers for which no spawning activity has been observed for 20 years or more. The dotted line defines the probable extent of occurrence, or at least the known part of it. In the case of Bay of Fundy populations, striped bass catch records are not enough to define the extent of occurrence in the bay, because it is also used by bass from U.S. rivers. On the south shore of the St Lawrence Estuary, about 200 specimens were collected between 1975 and 1994 (depicted by the “+” symbols in the figure). These are believed to be vagrants that originated from the Miramichi River.

Canadian striped bass populations occur in the northern portion of the species’ range. They form three groups: 1) the Bay of Fundy group, 2) the southern Gulf of St. Lawrence group, and 3) the St. Lawrence Estuary group. The Bay of Fundy group comprises three spawning populations: those of the Saint John, Annapolis and Shubenacadie rivers. In summer, the three populations fed in the Bay of Fundy and contact between them may have been possible. They also used waters in which migratory bass from U.S. rivers were present. The simultaneous presence of bass of Canadian and U.S. origin in the Bay of Fundy has been demonstrated by analysis of meristic and morphometric characters, recaptures of tagged specimens, the frequency of certain parasites, blood protein electrophoresis and DNA analysis (Melvin 1978; Dadswell et al. 1984; Hogans 1984; Harris and Rulifson 1988; Waldman et al. 1988; Wirgin et al. 1993, 1995; Diaz et al. 1997; Robinson 2000).

There is only one known spawning population in the southern Gulf, that of the Miramichi River. Striped bass have been captured in several New Brunswick estuaries that flow into the southern Gulf of St. Lawrence, e.g., the estuaries of the Nepisiguit, Miramichi, Kouchibouguac, Kouchibouguacis (Saint-Louis), Tabusintac, Tracadie and Richibucto rivers (Melvin 1991). However, these fish all seem to originate in the Miramichi River, where the only known striped bass spawning ground in the entire southern Gulf is found (Bradford et al. 1995; Robichaud-LeBlanc et al. 1996; Douglas et al. 2003). The southern Gulf population is believed to be isolated both from Bay of Fundy populations and from migratory bass from U.S. rivers. All recaptures of striped bass tagged in the southern Gulf were reported in this sector, except for one in Maryland (Hogans and Melvin 1984).

The population in the St. Lawrence Estuary, occurred in a roughly 300 km stretch of the fluvial and estuarine portion of the river between Sorel and Kamouraska. According to all available data, the St. Lawrence striped bass were isolated from the other Atlantic coast populations. There have been no reports of recaptures downstream from Kamouraska of bass tagged in the St. Lawrence (Beaulieu 1962; Robitaille 2001). This does not rule out the possibility of contacts, but they appear to be the exception. In the early 1980s, the capture of several dozen bass around the Gaspé Peninsula and in the middle St. Lawrence Estuary suggested the recovery of the local population. It appears that the fish were actually Miramichi River bass (R. Bradford, Department of Fisheries and Oceans, Science Branch, Maritimes Region, P.O. Box 1006, Dartmouth, Nova Scotia, B2Y 4A2, pers. comm.; Bradford and Chaput 1996; Douglas et al. 2003).

There are no known freshwater striped bass populations in Canada.