Full report - Conservation Gateway

Chapter 6 - Diadromous FishSelection of Target SpeciesAll diadromous fish species were initially considered forinclusion as targets, but those that are apparently stable orincreasing in number were ultimately not included. Thespecies included as primary targets show evidence of significantdecline or are already recognized as globally rare.Based on these criteria, eleven species of diadromous fishwere selected as primary targets for this assessment:• Alewife (Alosa pseudoharengus)• American eel (Anguilla rostrata)• American shad (Alosa sapidissima)• Atlantic salmon (Salmo salar)• Atlantic sturgeon (Acipencer oxyrhinchus)• Atlantic tomcod (Microgadus tomcod)• Blueback herring (Alosa aestivalis)• Hickory shad (Alosa mediocris)• Rainbow smelt (Osmerus mordax)• Sea-run brook trout (Salvelinus fontinalis)• Shortnose sturgeon (Acipencer brevirostrum)Population Status and the Importance ofNorthwest Atlantic regionThe Northwest Atlantic populations of some of these speciesare particularly important because the global range ofseven of the 11 target diadromous species is limited to theAtlantic coast of the United States and Canada.The conservation status of each of these species variesamong conservation programs (including among theInternational Union for the Conservation of Nature(IUCN), FishBase, and Natureserve programs; Table D1).The two species of sturgeon have a Natureserve globalrank of G3, considered “globally rare.” The sturgeons areconsistently recognized as highly threatened or vulnerable;shortnose sturgeon is listed as Threatened under theEndangered Species Act (ESA), and Atlantic sturgeonis a candidate for listing (currently a National Oceanicand Atmospheric Administration (NOAA) Species ofConcern, defined as a species about which the agency hasconcerns regarding status and threats but for which insufficientinformation is available to list the species under theESA). This designation does not carry any procedural orsubstantive protections under the Endangered Species Act(NMFS OPR 2009).Because of their complex history of extirpation and restocking,Atlantic salmon have a variety of legal statuseswithin the region, but they are generally regarded as imperiled.Atlantic salmon is considered stable in the northernportions of its global range in Canada and Europe,and is ranked G5, of “least concern.” However, the statusof populations within the Northwest Atlantic region insouthern Canada and the United States is poor. The onlyremaining wild Atlantic salmon populations in the U.Sare found in Maine. In 2000, all naturally reproducingremnant populations of Atlantic salmon from theKennebec River downstream of the former Edwards Damsite northward to the mouth of the St. Croix River wereadded to the Federal endangered species list as a DistinctPopulation Segment (DPS) (NMFS USFWS 2005). In2009 the Gulf of Maine DPS was expanded to includefish in the Penobscot, Kennebec, and Androscoggin riversand their tributaries (NMFS OPR 2009). The Gulfof Maine DPS has a global rank of G5T1Q, denoting thatthis population segment of the species is critically imperiled.Inner Bay of Fundy populations in New Brunswickand Nova Scotia are ranked G5TNR (not yet ranked), butthey were listed as Endangered by the Committee on theStatus of Endangered Wildlife in Canada in April 2001(COSEWIC 2008).The remaining species are all ranked G5, or “globallysecure” by Natureserve, but Fishbase vulnerability ranksvary from moderate to very high. Like Atlantic sturgeon,alewife, blueback herring, and rainbow smelt are listed byNOAA as Species of Concern. A 2004 petition to list theAmerican eel under the ESA was found to be “notwarranted” but noted numerous stressors in declines;ASMFC is currently conducting a stock assessment, due in2010 (ASMFC 2005). The American shad stock assessmentfound that stocks are currently at all-time lows anddo not appear to be recovering (ASMFC 2007). Recentdeclines of American shad were reported for Maine, NewHampshire, Rhode Island, and Georgia stocks, and forthe Hudson (New York), Susquehanna (Pennsylvania),6-2Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report