Life History

The life history of this species is not well known. Surveys conducted to date were focused on finding locations where the PCC currently survives and attempting to characterize those habitats and to begin management on easements when possible. Quantitative studies of population densities and the life history were not part of the surveys, although abundance records were captured during certain years. As a result, there are only fragments of information regarding breeding seasons, seasonal occurrence of juveniles, fecundity, and population density.

Butler et al. (2003) provides an overview of crayfish of North America and generalities obtained from the study of a few of the many species of cambarid crayfishes:

  1. Generally in the southern United States, crayfish mate in the spring and the fertilized eggs adhere to the female’s swimmerets while she sequesters herself in a safe place while “in berry” (her egg mass resembles berries). Upon hatching, the young remain with the female for the first three molts before leaving for an independent existence. Brown and Gunderson (1997) stated crayfish are ectothermic, meaning their body temperature is the same as the environmental temperature. Reproduction is cued by seasonal changes (particularly temperature) and growth of juveniles tends to be during the period of maximum availability of food and optimum temperature. This is in response to seasonal changes, also. Optimum temperature for crayfish, regardless of species, is generally thought to be in the range of 68-79o F (20- 26o C).
  2. Molting or shedding of the exoskeleton provides a period for growth before the new exoskeleton hardens. This is a critical time for crayfish due to increased vulnerability to predation and pollutants.
  3. Many crayfish species have a maximum life span of 1.5 to 3.5 years. According to Hobbs (2001), cambarid crayfishes live about 2.5-3 years. The majority breed more than once, with mating among mature yearlings frequent; however, many individuals do not become sexually active until late summer or fall.
  4. Crayfish can be keystone predators in some situations. Some species of crayfish are omnivorous and feed on a wide variety of food items, including plant material, detritus, carrion, and live prey (Smith et al. 2011).
Table 2.2. Current information regarding reproduction is sparse but shows similar reproductive periods during the year for four closely related species. Slight modifications from Keppner and Keppner (2014).
Crayfish
Form I Males
Females with Eggs
Females with Young
Hatchlings Captured
P. apalachicolae April, May, June, October May & June June no data
P. econfinae(PCC) April & June March through September March through December March-April
August-December
P. hubbelli February, March, April, June April & May No data no data
P. kilbyi February-June & October-November May & June May-June (Hobbs 1942) no data

Information summarized below is more specific to the PCC and depicted in a life cycle in Figure 2.8:

  1. Males alternate between reproductively mature forms (Form I) and nonreproductive forms (Form II) through a continuous series of molts (Taylor et al. 1996, p. 27). Most breed more than once, with mating among mature yearlings frequent. PCC Form I males have been captured in April and June (Hobbs 1942, Keppner and Keppner 2014)
  2. There are multiple instances of females captured from burrows with eggs or young and even adult males in the presence of females with young (Hobbs 1942, Keppner and Keppner 2002, FWC 2017 dataset) (Table 2.2).Female PCC have been found with eggs and/or young from March through September. Juveniles are most frequently found in the summer and have been observed through December, so young appear to be produced from at least March to December. Juveniles can be carried overland by sheet flow during rainy periods, which aids in dispersal (Keppner and Keppner 2002) (Table 2.2). Juveniles about the size that just detached from the females (from 15-25 mm in length) were netted a number of times in December 2003 (Keppner and Keppner 2004). However, the number of juveniles encountered decreased from September through December (seasonal dry period)(Table 2.2). During the normal, seasonal dry conditions experienced from April through May, captures are challenging due to limited surface water. We developed a conceptualized life cycle diagram for the PCC based on available life history information but when information was lacking we relied on data available regarding another semi-terrestrial crayfish, Procambarus hayi (Figure 2.8) and general crayfish life history information (Butler et al. 2003; Longshaw and Stebbing 2016).
    PCC lifecycle
    Figure 2.8. Conceptualized PCC Crayfish Life Cycle integrated with P. hayi (Longshaw and Stebbing 2016).
  3. Adult and juvenile PCC crayfish held in captivity have often died during molting phases where neither predation nor pollutants were issues, but perhaps they lacked certain minerals to successfully complete the process (Patty Kelly pers. comm. 2017). Almost all specimens held in aquaria molted at least once during their captivity if captivity was of sufficient duration (Keppner and Keppner 2014). One juvenile molted twice within a span of two months in captivity (Patty Kelly, USFWS, pers. comm. May 2017).