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HomeMy WebLinkAboutNC0004979_Balanced & Indigneous Populations Review_20100105i i 'x - January 5, 2010 Memorandum To: From: Eric Fleek Subject: Balanced and Indigenous Populations Review—Benthos Communities. Lake Wylie Near Allen Steam Station (NPDES Permit No. NC0004979) I have reviewed the subject document and offer the following comments and changes for future documents: 1) For future reports, (in addition to Tables 4-2, 4-3, 4-4) include a taxonomic table comparing taxa occurrences for the current sampling year for EACH station so that a direct side-by-side comparison for each taxon by each station for the sample year can be more easily conducted. Please see Table 1 below as an example. Table 1. Waterbody: LICKLOG BR Date: 8/9/2007 Location: SR 1706 County: Jackson Taxon EPHEMEROPTERA ACENTRELLA SPP PLAUDITUS DUBIUS GP C BAETIS FLAVISTRIGA BAETIS INTERCALARIS BAETIS PLUTO PSEUDOCLOEON PROPINQUUM SUGARLOAF CR SCOTT CR 8/9/2007 8/9/2007 OFF SR 1708 OFF SR 1556 Jackson Jackson 2) For future reports, (in addition to Figures 4-1, 4-2, 4-3, 4-4, and 4-5) include the following graphs for each station and year (in the same format as currently presented) for the following groups: Non-Chironomid Diptera, Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, Odonata, Megaloptera, Crustacea, and Mollusca. Again, this will allow for a more direct side-by-side comparison for each station and each taxonomic group. In addition, EPT taxa richness and EPT density should also be reported for each station going forward. These metrics can be reported in accordance with current graphical formats. 3) As can be seen in Figure 1, there appears to be a very large discrepancy in the mean and total abundance of the burrowing mayfly Hexagenia spp. between Station A (Upstream of Allen Steam Station), Station B (at Allen Steam Station), and Station C (Below Allen Steam Station). Indeed, Hexagenia spp. were collected at every sampling effort from 2000-2008 at Station A (Upstream) but only collected twice (2000 and 2006) at Station B, and on four occasions (2001, 2004, 2005, and 2007) at Station C. Hexagenia spp. have been reliably demonstrated to be sensitive to low dissolved oxygen (Britt 1955, Beeton 1961, Beeton 1969, Verduin 1964, Carr and Hiltunen 1965, Krieger et al. 1996, Edsall et al. 1999, Edsall 2001, Edsall and Phillips, 2006) as well as being sensitive to metals and petroleum products (Edsall et al. 1991, and Schloesser et al. 1991) and have long been recognized as pollution intolerant organisms and reliable indicators of overall healthy aquatic conditions (Bertram and Statler-Salt 1998, Edsall 2001). Therefore, the discrepancy in the densities of these organism between stations is concerning and requires additional explanation since it appears that these discrepancies are not the result of seasonal, depth, or substrate differences between sites. t, _. l +'�A �y I Figure 1. Annual, Mean, and Total Hexagenia spp. Density by Station: Lake Wylie, Near Allen Steam Station. 2000 2001 2002 2003 2004 2005 2006 2007 2008 MEAN TOTAL DENSITY DENSITY Station A (Uptake of Allen Stream Station) m Station B (At Allen Steam Station) ❑ Station C (Downlake of Allen Steam Station) References Cited Beeton, A.M. 1961. Environmental changes in Lake Erie. Trans. Am. Fish. Soc. (90): 153-159. Beeton, A.M. 1969. Changes in the environment and biota of the Great Lakes. In: Eutrophication: Causes, Consequences, and Correctives. National Academy of Sciences. Washington, D.C., pp. 150-187. Bertram, P. and N. Statler-Salt. 1998. Selection of indicators for Great Lakes basin ecosystem health. State of the Lakes Ecosystem Conference 1998. Buffalo, New York. U.S. Environ. Protect. Agency, Chicago, Ill., and Environment Canada, Burlington, Ont. Britt, N.W. 1955. Stratification in western Lake Erie in summer 1953: effects on the Hexagenia (Ephemeroptera) population. Ecology (36): 39-244. Carr, J.F. and J.K. Hiltunen. 1965. Changes in the bottom fauna of western Lake Erie from 1950 to 1961. Limnol Oceanogr. (10): 551-569. .,�,� t :: :., i