### MEMORANDUM

Tetra Tech, Inc. 400 Red Brook Blvd., Suite 200 Owings Mills, MD 21117 phone 410
- 356
- 8993 fax 410
- 356
- 9005

DATE: March 2 0 , 2008
TO : Paul Shriner, EPA
FROM : Henry

L atimer , Blaine Snyder , and Chris Millard
SUBJECT: Taxonomically

- based fish species grouping scheme

As part of a larger effort to interpret potential impingement mortality and entrainment (IM&E) effects, it is desirable to organize fish species into groups with similar IM&E vulnerabilities. I deall y, these groups wou ld comprise fish species with similar characteristics (e.g., swim speed, schooling behavior, reproductive and life history characteristics) as well as habitat preferences (e.g., benthi c vs. pelagic, river vs. lake, freshwater vs. estuarine). However, give n the number of fish species potentially exposed to IM&E and the effort required to summarize relevant information to be used in grouping these species, a first effort based simply on taxonomy

has been undertaken. The goals of this effort are to 1) help d efine the scope of the species grouping effort and 2) better understand the ty pes of information required to successfully assemble species into meaningful groups. There are currently

3,694 fish species in North America (Nelson et al

. 2004). Functionall y , man y of these species are not likely to be exposed to cooling water intake structures (CWI S) in the U.S., either because they occur onl y in Mexico or Canada or are pelagic marine species that are unlikel y to occur in near

- shore waters. The list of North American fish species was screened to eliminate those that do not occur in the U.S. and those that are unlikel y to occur in near

- shore waters. Following this screening, 1,279 species remain that could reasonabl y be expected to occur in the U.S. in the vi cinity of CWI Ss and be exposed to IM&E related to those CWI Ss. This list includes all freshwaterand most (if not all) estuarine fish. Future , comprehensive species grouping efforts will

require that marine species be reviewed in greater depth to determi ne which species should be considered to be reasonabl y vulnerable to IM&E. To minimize the number of fish species groups, the taxonomic level selected for use as a basis for groupings must be fairl y general, but specific enough to capture meaningful morph ological and habitat

- specific differences among the various species. For this exercise, we selected Family as the appropriate level for use as the basis in establishing groups. Dividing the groups based on Class was determined to result in species groupi ngs that lumped clearl y dissimilar species together. Groups based on Genera would be preferable in terms of lumping more similar species together, however such an approach yi elds so many

groups ( 278) as to limit the utility of a grouping approach. The family

- level evaluation yi elds 72 different groups (see attached spreadsheet ). It is likely that in refining this approach , similarities among some Families will be identified that will allow for several of these distinct groups to be combined. However, it is also known that variations in morphology and preferred habitat within some Families will require that those groupings be further sub

- divided. Based on a brief anal ys is, i t is possible that some species from differing families could be combined. For example, some members of the sculpin Family ( Cottidae ) would be able to be combined with some members of the Perc h Family ( e.g., darters), in that some species within each group exhibit similar, benthic habitat preferences. However, f urther investigation into habitat preferences, geographic ranges, and swim speed analy ses is required before such groupings can be made. It is also likely that some, more diverse Families would require further division to more accurately represent the IM&E vulnerabilities of these groups. For instance, the minnow family ( Cy prinidae ) which contains carp, minnows, and pike minnows would likely have to be divided into at least three groups that are reflective of the diverse body sizes, habitats, and swim speeds of fish within th is family

. Thus, while a taxonomically

- based species grouping effort is a reasonable initial step in grouping fish species in terms of IM&E vulnerability , there are clear shortcomings of this approach. To assemble larger and more inclusive species grou ps , the scientific literature must be evaluated to gather data on species

- specific habitat preferences, geographic range, and swim speeds. Such information is required to determine whether the groupings based on potential IM&E vulnerability are similar to existing taxonomic groupings and, if not, how such groupings could be refined. Further, information should be assembled for more than one life

- stage to ensure that the IM&E vulnerability of potentially

more sensitive (but less well

- studied) life stages ( e.g., egg) are adequatel y addressed. Itis likel y that the scientific literature does not contain complete, relevant information for the majority (possibly the vast majority) of species. Itis expected that this more in depth approach would be able to pr opose IM&E vulnerability values for a subset of all fish species. These values would then be extrapolated and applied to all taxonomically

similar species within each group . The scientific validit y of the finalproposed grouping schemes would be directl y dependent upon the amount of available

species

- specific data available in the literature. An alternative approach would be to refine the species list (currently 1,279 for freshwater and estuarine in the U.S. and 3,694 if all North American fish are inc luded) based upon those fish that can reasonably be expected to be subject to IM&E. A judgment as to which species can reasonably be expected to be subject to IM&E could be made based upon an anal ys is of those fish species actually impinged and entrained through CWI Ss at representative facilities (e.g., encompassing intake ty pes, sizes, and locations) throughout the U.S. Such data from facilities located in all geographic (e.g., Northeast, Southwest, Midwest) areas and water body t yp es (e.g., river, lake, Great Lakes, estuary, marine) have alread y been collected and are available in state and/or EPA records. Evaluation of assembled impingement and entrainment (I&E) data would be expected to yield a much more limited list of species which are demonstrably subject to IM&E in the U.S. A list of species that are actuall y subject to IM&E would be useful for a variety of reasons. This list would be expected to represent a small percentage of all species in the U.S., thus enabling species grouping efforts to be streamlined, more relevant, and likely more scientificall y defensible. Such a list would also reveal real

- world data that is directly relevant to species specific IM&E vulnerability which may

be more useful that literature

- derived data that may have qu estionable application in determining IM&E vulnerability

. The resulting list would also allow alternative approaches to be explored to evaluat e and regulat e IM &E. Further, this list would allow EPA to make more informed decisions as to how IM&E regulatio ns should be applied to various water body t ypes and how the various water body t ypes could reasonably be combined (e.g., address whether separation of lakes and rivers is appropriate or necessary). We are optimistic that some ty pe of species grouping sch eme is possible. However, we believe that inclusion of actual I&E data is a necessary step to screen the list of all possible fish species to assemble a list of fish species that can reasonably be expected to be subject to IM&E. Using this revised list, a more appropriate and defensible IM&E vulnerabi lity

assessment could be made of each species, and reasonable species groupings could then be assembled with a fairly high degree of confidence.
Literature Cited Nelson, J.S., E.J. Crossman, H. Espinosa

- Per ez, L .T. Findley , C.R. Gilbert, R.N. L ea, and J.D. Williams. 2004. Common and scientific names of fishes from the Unites States, Canada, and Mexico. American Fisheries Society , Special Publication 29, Bethesda, Maryland.