Full ecoregional plan - Conservation Gateway

merrlowctcapeupctmidct3E-03100Native Fish and G1-3 Mussels by EDUDistance (Objective Function)4.4E-028.6E-021.3E-01Information Remaining (%)7550251.7E-010A Sorensen Similarity Distance Index analysis using all native fish and G1-G3 musseldistribution (current and historical presence/absence) showed the distribution of species withinthe Saco-Merrrimack-Charles EDU and Lower Connecticut EDU are extremely similar. TheLower Connecticut EDU and Saco-Merrimack-Charles EDU shared 40 of 47 species. The onlydifferences was that satinfin shiner, gizzard shad, rainwater killifish, sheepshead minnow did notoccur in the Saco-Merrimack-Charles and lake trout, lake whitefish, and northern redbelly dacedid not occur in the Lower Connecticut. The satinfin shiner, rainwater killifish, sheepsheadminnow, and gizzard shad appear to be at the northeastern limit of its range. The satinfin shineroccurs in only the Saugatuck watershed within the Lower Connecticut EDU, but its distributionextends extensively south to North Carolina. The sheepshead minnow, rainwater killifish, andgizzard shad occur in coastal estuarine areas from Cape Cod to Texas but do not appear to havebeen able to colonize north of the Cape (Williams 2002). Lake trout and lake whitefish are likelyabsent from the Lower Connecticut EDU as they prefer cold deep lakes and cold large rivers thatare lacking in the Lower Connecticut EDU. Northern redbelly dace prefer colder boggy waterand sluggish mud bottom creeks and boggy ponds that are also absent in the Lower ConnecticutEDU.The next most similar EDU to the Lower Connecticut and Saco-Merrimack-Charles is the CapeCod EDU. These three EDUs share 29 of the total 53 fish species . All fish in the Cape Cod EDUalso occured in the Lower Connecticut EDU, and 27 of the 29 Cape fish also occurred in theSaco-Merrimack-Charles EDU (Sheepshead minnow and rainwater killifish were missing fromthe Saco-Merrimack-Charles, per above distribution limit discussion.) The fish fauna of the Capethus appears to be a subset of the fauna of the Lower Connecticut and Saco-Merrimack-Charlesedu. Native Fish that occurred in all EDUs except for the Cape Cod EDU included lake trout,spottail shiner, lake chub, longnose sucker, atlantic salmon, slimy sculpin, creek chub, longnosedace, redbreast sunfish, and blacknose dace. As mentioned previously, the Cape Cod EDU lacksany rivers greater than size 2 and has quite uniform low gradient physical habitat throughout andthis limited physical habitat diversity likely limits the number of species that can find adequatehabitat in this EDU.The Upper Connecticut EDU and Middle Connecticut EDU show greater divergence from theCape, Lower Connecticut, and Saco-Merrimack-Charles EDUs. The Upper Connecticut andMiddle Connecticut EDUs share 26 species of their 38 total species. One species, eastern silveryminnow, occurred in both the Middle Connecticut and Upper Connecticut but was missing fromthe Lower Connecticut, Cape, and Saco-Merrimack-Charles. Eight fish species (alewife,American brook lamprey, fourspine stickleback, hickory shad, ninespine stickleback, stripedbass, swamp darter, and threespine stickleback) occurred in the Lower Connecticut, Cape, andSaco-Merrimack-Charles but did not occur in either the Upper or Middle Connecticut EDU.REVISED 6/2003AQUA-RESULTS-8