Orconectes (Procericambarus) rusticus (Girard, 1852)

Loughman, Zachary J. & Simon, Thomas P., 2011, Zoogeography, taxonomy, and conservation of West Virginia's Ohio River floodplain crayfishes (Decapoda, Cambaridae), ZooKeys 74, pp. 1-78 : 39-42

Orconectes (Procericambarus) rusticus (Girard, 1852)

Cambarus rusticus Girard 1852:88. Faxon 1885:108, fig. 8.

Cambarus juvenilis Hagen 1870:66, figs. 29-33, 157.

Cambarus (Faxonius) rusticus Ortmann 1905b:112.

Faxonius rusticus Williamson 1907:753. Creaser 1933a:5.

Cambarus (Faxonius) rusticus rusticus Ortmann 1931:82.

Cambarus (Faxonius) juvenilis Ortmann 1931:84 [in part].

Faxonius (Faxonius) rusticus rusticus Creaser 1933b:21.

Orconectes rusticus rusticus Hobbs 1942a:352. Fitzpatrick 1963:61.

Orconectes (Orconectes) juvenilis Hobbs 1942b:154.

Orconectes rusticus Pennak 1953:465. Hobbs 1972:92, figs. 74c, 75 b–d. Page 1985:412, figs 145-147. Taylor et al. 1996:31. Taylor et al. 2007:385.

Procambarus rusticus Huner 1978:4.

Orconectes (Procericambarus) rusticus Fitzpatrick 1987:58. Hobbs and Jass 1988:66-78, figs. 46 a– 46m, 47-49. Hobbs 1989:49, fig. 174. Jezerinac et al. 1995:52-58, figs 23 a– 23h. Taylor 2000:132. Taylor and Shuster 2004:192-195, figs. 163, 164 A– 164G.

Diagnosis.

Rostrum with concave margins, not thickened, with spines or tubercles; median carina absent; mandible with smooth cutting edge. Cephalothorax oval, slightly dorsoventrally compressed in profile. Areola 4.6-19.4 times longer than wide, comprising 36-39% of TCL, with 2-3 rows of punctations across narrowest region; branchiostegal spine poorly developed; suborbital angle obsolete or poorly developed. Chelae robust; mesial surface of palm with two rows of defined tubercles, first row with 5-9 tubercles; second row with 4-9 tubercles of smaller diameter. First form male gonopods long, comprising 26% of TCL, with 2 straight terminal elements; central projection comprising 56% of gonopod length; well developed shoulder at cephalic base of central projection. Second form male gonopod non-corneous, straight, mesial process slightly subequal in length to central projection, blunt, shoulder not evident. Annulus ventralis rhomboid in shape, fossa moderately large, cephlolateral prominences well developed, trough narrow, sinus evident on caudal surface.

Color in life.

Carapace and abdomen dark green or brown; large rusty lateral blotch present on each side of posterior margin of carapace; fixed finger of propodus and dactyl with red tips and black band; ventral surfaces cream or white.

Specimens examined.

Orconectes rusticus were only collected from Marshall County at two locations in the current study, as listed below.

MARSHALL COUNTY: PPG Wildlife Management Area adjacent to RT 2 S, 39.736244 -80.84638; 21 March 2006 - (WLU 06032103), 1 I♂; 18 April 2006 - (WLU 06041802) 4 I♂. WETZEL COUNTY: Ohio River backwater at Marshall/Wetzel County line, 39.717846 -80.514959; 2 April 2004 - (WLU 04040203), 4 I♂, 3 O♀; 11 April 2004 - (WLU 04041101), 3 I♂, 3 O♀; 21 March 2006 - (WLU 06032101), 10 I♂, 1 O♀; 18 April 2006 - (WLU 06041801) 9 I♂, 3 ♀.

Distribution.

Orconectes rusticus (Figure 23)is native to lower and central portions of the Ohio River system in Kentucky, Ohio, and Indiana north to western portions of Lake Erie in southeastern Michigan and north western Ohio ( Taylor 2000.), and is one of two invasive crayfish species in West Virginia. Prior to this survey, it appeared to be limited to Four Pole Creek in Huntington, and isolated sections of the Kanawha and Little Kanawha River systems. Both floodplain populations are allied with the upper Ohio River South basin in the northern panhandle (Figure 10) and are associated with Ohio River embayments adjacent to industrial sites. Additional investigators discovered Orconectes rusticus populations throughout the Kanawha River system in recent years (Casey Swecker, Marshall University, personal communication).

The Upper Ohio South basin is the only basin within the floodplain that currently harbors Orconectes rusticus populations. Bayer Chemical Plant and Pittsburgh Paint and Glass (PPG) Chemical Plant both possess embayments connected to the Ohio River mainstem that contain Orconectes rusticus populations. The PPG population is present in a “pond” with a connection to the Ohio River mainstem. The Bayer population is present in a series of backwaters with mainstem connections. Trapping results show that the Bayer population has higher densities than the PPG population.

Why Orconectes rusticus is limited to these two backwaters despite its presence in the Ohio River mainstem needs furthur investigation. Populations present in the mainstem could operate as sources for future invasions into new watersheds. The extent of the range of Orconectes rusticus within the mainstem is also in need of future work. Given the Ohio River’s manipulation into a series of non-contiguous pools, investigations into those pools that harbor Orconectes rusticus populations and those pools that do not is a proactive move to understand basins at risk of future invasions.

Morphometrics.

Forty-four Orconectes rusticus were collected from two sites. The largest individual was an ovigerous female 44.1 mm TCL. The largest male was a 38.4 mm TCL form I male from PPG Wildlife Management Lake. Mean Orconectes rusticus TCL was 31.0 mm (n = 41, SE = 6.12). Nine females were ovigerous and had a mean carapace length of 30.1 mm. Morphometrics data for Orconectes rusticus is presented in Table 12.

Habitat and natural history.

In West Virginia’s Ohio River floodplain, Orconectes rusticus inhabits two Ohio River back- waters (Figure 10). Both embayments are nutrient rich, shallow, lentic systems with an abundance of detritus and algae. Nutrient-rich environments are preferred habitats of Orconectes rusticus and Ohio River backwaters provide ideal conditions for the species ( Hobbs et al. 1989; Lodge et al. 2000a). All Orconectes rusticus collected in this study were trapped in late winter and early spring. Very little natural behavior was observed.

Life history parameters of the Bayer population were determined from specimens and a review of the literature. All males captured in traps in March and April were form I and possessed heavily encrusted carapaces. The level of encrustation is directly proportional to the length of time between molts ( Hobbs 1981). Given the conditions of collected males, which in many instances were black and encrusted, individuals likely molted into form I the previous fall. Other Orconectes rusticus populations undergo a late summer/fall mating season, and it is likely that this population may mate during the fall as well ( Jezerinac et al. 1995, Taylor and Schuster 2004).

Ovigerous females were collected on 2, 14, and 18 April 2006 (Table 9). Seventy percent of females were ovigerous at this time. Egg counts increased with female size and ranged from 75 ova for 26.5 mm TCL to 356 for a 35.9 mm TCL female. Mean egg diameter was 1.8 mm. There was not a correlation between egg number and TCL (r2 = 0.18, n = 7); however, this could possibly be an artifact from small sample size. Date of egg extrusion and counts are similar to native Kentucky populations at similar latitudes (Prins 1968). Females likely mate in the fall, hold active sperm inside spermatheca throughout the winter, and extrude eggs in late-March. Orconectes rusticus in previous life history studies were noted to undergo the typical Orconectes life history cycle, which has been explained in the Orconectes obscurus natural history section (Prins 1968; Capelli 1982; Jezerinac 1982).

Orconectes rusticus expansion into new territory was observed at the Bayer site. A headwater stream that was not connected to the Bayer series of backwaters became connected to this system in the spring of 2004. At this time extensive survey efforts were undertaken to determine if Orconectes rusticus was present within the stream; none were found. Ten months after initial surveys of this stream, Orconectes rusticus had migrated 2 km upstream.

Conservation status within study area.

Given the aggressive natureof this invasive species, annual monitoring efforts are warranted. The impact of this species on native crayfish communities in northern West Virginia is unknown and should be determined as soon as possible.