Re: NANFA-- conservation status of SE fishes

Christopher Scharpf (
Mon, 09 Oct 2000 09:52:24 -0400

>This article states that the southern U.S. has more native fishes than any
>other area of comparative size north of Mexico.

In the abstract, the text reads: "The southern United States supports more
native fishes than any area of comparable size on the North American continent
north of Mexico..."

Notice that it says "more native fishes" as opposed to "more native fish
species." Is this sentence referring to abundance or diversity? The context
indicates diversity, but a literal reading of the sentence indicates abundance.
Either way, it's ambiguously stated.

After the abstract, the first sentence reads: "The southern United States has
the richest fish diversity and highest number of endemic fishes in North America
north of Mexico (Burr and Mayden 1992; Warren et al. 1997)."

Okay, this sentence is clearly about diversity, and endemism...but the ways it's
written suggests that Mexico has a higher fish diversity and rate of endemism.
Is this accurate? I checked the two sources cited in the text.

Warren et al. 1997 state: "The southeastern United States harbors the richest
freshwater fish fauna on the North American continent north of Mexico (Burr and
Mayden, 1992)..."

Not much help there. So I turned to Burr and Mayden but found no comparable
statement. However, Mexico appears to have a higher rate of endemism, with
around 212 endemic species. The southeast U.S. has far fewer, probably less than
100. (Note: the Fisheries article defines the "southeast" more broadly than Burr
& Mayden.)

However, a 1993 checklist of Mexican fishes lists 448 native species, far fewer
than the 600+ found in the southeast U.S. So it appears to me that the U.S. is
indeed the most diverse fish region on the continent, both inclusive and
exclusive of Mexico. Why the authors of the Fisheries article worded their
assessment so conservatively is anyone's guess. Since Mexico's fish fauna is not
as well studied as in the States, perhaps many new species await discovery.
Maybe Dave Neely can run down the hall and ask Rick Mayden about this.

>What then is the part of
>North America (the Nearctic part) which has the most native fishes? Obviously
>it's in Mexico,but which part; northern or central? Just curious about which
>part of North America has the most native fish species.

According to Burr & Mayden (p. 26):

Mississippi faunal province -- 31 genera, 375 species, 34% endemic
Southeastern faunal province -- 31 genera, 268 species, 29% endemic
Central Mexico faunal province -- 25 genera, 205 species, 63% endemic
Central Appalachian faunal province -- 28 genera, 177 species, 25% endemic
Great Lakes faunal province -- 27 genera, 168 species, 0.03% endemic
Rio Grande faunal province -- 21 genera, 134 species, 50% endemic
Western Gulf faunal province -- 24 genera, 132 species, 0.06% endemic
Northern Appalachian faunal province -- 27 genera, 106 species, 0.001% endemic
Hudson Bay faunal province -- 19 genera, 101 species, 0% endemic
Great Basin-Baja-Klamath-Sacramento faunal province -- 16 genera, 98 species,
58% endemic
Yukon-Mackenzie faunal province -- 14 genera, 64 species, 0% endemic
Cascadia faunal province -- 11 genera, 60 species, 25% endemic
Sonoran-Sinloan faunal province -- 15 genera, 45 species, 36% endemic
Colorado faunal province -- 7 genera, 32 species, 69% endemic
Arctic Archipelago faunal province -- 3 genera, 8 species, 0% endemic

Note: The Fisheries article defines the southeast to include all of the
southeastern faunal province, and parts of central Appalachian, Mississippi, and
Western Gulf slope.

Chris Scharpf

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