The Hidden Beauty of the Neosho Midget Crayfish

If there’s a group of animals that gets my complete affection without reservation it is the crayfish. I’m a alum of David Lodge’s lab at the University of Notre Dame, and although David has now moved very strongly into the realm of scientifically informing policy, back in the day he was a huge crayfish guy. Several members of his lab still work pretty exclusively on Orconectes rusticus (the dreaded Rusty Crayfish), and so I spent a lot of my graduate career thinking about crayfish. Plus they are just awesome.

The Neosho Midget Crayfish (Orconectes macrus [Greek, meaning long, in reference to long gonopods]) is a small crayfish found exclusively in the Neosho River Basin, and really almost exclusively in the Spring River Basin (Pflieger 1996). The historic range was probably more extensive, but despite its name, I think it is unlikely this crayfish occurred throughout the greater Neosho River Basin. In Kansas, this species occurs in the Spring River basin, although apparently very rarely. Beasley and Branson (1971) found these crayfish in the Missouri portion of the Spring River, but no where else in the drainage basin. Pflieger (1996) describes the species as “common…in most streams of the Neosho drainage except for North Fork of Spring River in Jasper and Barton counties.” I don’t want to suggest Pflieger is wrong, but if this is accurate, these are the only places on Earth the crayfish is common. Durbian et al. (1994) surveyed crayfish in Cherokee County Kansas (including the Spring River) and found no individuals of this species. Taylor et al. (2004) in their review of Oklahoma crayfish referred to the species as rare or uncommon and did not find it in the Spring or Neosho main-stem. The Kansas Department of Wildlife and Parks did find two individuals in the Spring River in 1996 (Ghedotti 1998), at a location they had been found at historically, but this apparently was the result of considerable sampling effort. More recently, consultants sampling around a power plant in the Spring River collected 12 individuals labeled O. rusticus. Further inspection of a voucher specimen revealed it to be O. macrus (whew!), so the species does still occur in Kansas (KDWP, pers. comm).

The Neosho Midget Crayfish is a Species in Need of Conservation (SINC) in Kansas, which means selling or take of this species are illegal, but does not afford it the kind of protection granted Threatened and Endangered species. For example, projects occurring in the habitat of Neosho Midget Crayfish do not require a Kansas Department of Wildlife and Parks (KDWP) Action Permit. However, KDWP does devote some special consideration to research projects involving SINC species, and we happen to know of a graduate student at Fort Hays State who is conducting a state-wide crayfish survey with some special emphasis on this species (or at least this area).

Like most crayfish, this species is considered to be opportunistic omnivores who will eat decaying vegetation and animal matter, as well as predate on invertebrates and small fish. According to Pflieger (1996) the species behaves more like Cambarus spp. in Missouri than like other Orconectes spp. Having not worked with Cambarus spp. in the past, I’m not really sure what he means, but this species appears to be pretty sedentary, spending most of its time under rocks or in tunnels. According to Pflieger “…not an agile or strong swimmer, and seldom takes evasive action when attempts are made to capture it by hand.” Reproduction apparently occurs in March or early April, and females virtually disappear from sampling collections during April (presumably because they were sequestered in burrows and thus unable to be collected).

The Spring River in Kansas has been the brunt of some fairly severe pollution impacts over the course of its history. The EPA has a 115 mile square Superfund site in this county (see here and here .pdf) from a history of heavy zinc and lead mining, and the Spring River is heavily polluted. Likely due to this pollution history and some fairly extensive development in SE Kansas, a number of species have become endangered or rare from the Spring River drainage. The Neosho Midget Crayfish appears to consist of several isolated populations in tributary streams that are kept disconnected by poor quality habitat in the main-stem of the Neosho and Spring Rivers. In particular, my feeling is that the Spring River in Kansas is a particularly crucial connection between apparently abundant subpopulations in Missouri and isolated populations in Arkansas, Oklahoma and Kansas. Without a strong avenue to re-connect these isolated populations, the entire species is at risk from localized impacts and genetic drift.

Lit cited:

Beasley and Branson. 1971. A partial biological survey of the Spring River drainage in Kansas, Oklahoma, and Missouri Part III. The Crayfishes. Transactions of the Kansas Academy of Science 74:228-233.

Durbian, F.E., B.J. Frey, and D.W. Moore. 1994. Crayfish species from creeks and rivers of Cherokee County, Kansas. Transactions of the Kansas Academy of Science 97:13-17.

Ghedotti, M.J. 1998. An annotated list of the crayfishes of Kansas with first records of Orconectes macrus and Procambarus acutus in Kansas. Transactions of the Kansas Academy of Science 101:54-57.

Pflieger, W.L. 1996. The Crayfishes of Missouri. Missouri Department of Conservation. 152 pp.

Taylor, C.A., S.N. Jones, and E.A. Bergey. 2004. Crayfishes of Oklahoma revisited: New state records and checklist of species. The Southwestern Naturalist 49:250-255.