- Scientific name: Faxonius limosus
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
Description
Spinycheek crayfish
The spinycheek crayfish is a medium-sized crayfish in the crustacean order Decapoda. Adults tend to be brownish-tan or olive-green in color and typically with brown-reddish bands on the abdominal segments. This species is named after its generally smooth carapace with hepatic spines on it sides. The rostrum (a projection between the eyes) with marginal spines and distinctly pointed acumen. Their relatively small, smooth, and robust claws typically have orange tips and black bands. Males and females are distinguished by the presence in males of highly modified pleopods (abdominal appendages) on the first two abdominal segments. The pleopods are unmodified in females. The tips of the first pair of pleopods or gonopods in reproductive males (form 1 males) are divergent.
Other species similar in morphology include other species of Faxonius including nonnative and invasive species rusty crayfish (F. rusticus) and virile crayfish (F. virilis). Spinycheek crayfish is differs in the shape of its gonopods and is the only species with hepatic spines. See identification keys for descriptive and illustrated differences (e.g., Hobbs 1989, Smith 2000).
Life cycle and behavior
Little is known of the life cycle of spinycheek crayfish in Massachusetts, but other populations have been studied in its range. Mature females lay their eggs and attach to their abdomen in April to May and hatch in May into June (Momot 1988). Hatched young stay with the female until they grow large enough to be free-living juveniles later in the summer months. Sexual maturity is reached in the second year after several molts and reproduce in following years (Hamr 2002). Mating typically takes place in spring and early summer (Momot 1988). Not all fully grown males can engage in sexual activity at a specific time because males of all species in the family Cambaridae undergo cyclic changes in the reproductive morphology. During the inactive phase, the sexual organs of the male are reduced and become non-functional. Once breeding has occurred, females become very inactive and find a location that will successfully conceal them during the egg-laying and brooding period. This is species has an average life span of 2 years but can reach 4 years (Hamr 2002). The species is considered a tertiary burrower.
Distribution and abundance
The spinycheek crayfish ranges from Virginia to Canada along Atlantic slope watersheds. The species is considered nonnative in portions of Canada. In Massachusetts, spinycheek crayfish has been recorded in every major watershed. In the past 25 years, the species has been found in the Housatonic, Connecticut, Taunton, and Cape Cod watersheds but likely reflects limited survey effort.
The status of F. limosus is uncertain in Massachusetts. The species is considered native to most Massachusetts watersheds including the Housatonic, Connecticut, and Quinebaug Rivers. Occurrences in the Merrimack, Charles, and southeastern Massachusetts watersheds may represent accidental introductions (Smith 2000). However, this has not been confirmed.
Habitat
The spinycheek crayfish inhabits medium to large sized streams with low to moderate flow and lentic habitats including lakes and ponds (Smith 2000). Substrates range from silt and mud to more rocky conditions.
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Low gradient, moderate-sized stream habitat typical for spinycheek crayfish.
Threats
Threats to spinkycheek crayfish include invasive crayfish species (F. rusticus, Procambarus clarkii) via competition, chemical pollutants, accelerated eutrophication, road salts, channelization, and habitat fragmentation by dams.
Conservation
Survey and monitoring
Standardized surveys are needed to update the status of this species in Massachusetts. Crayfish-specific surveys have not been applied for more 30+ years. Efforts should target the species statewide including potentially introduced watersheds.
Management
Preventing the introduction and spread of invasive crayfish and protecting historical stream habitat is critical for the spinycheek crayfish. Controls over invasive species vectors including live fish bait shops, improper storage and disposal in educational environments (i.e., school classrooms), and the pet trade, should be put into place for Massachusetts. Preservation of riparian forests, restoration of channelized stream reaches, dam removal (in some cases), and reduction of chemical runoff from roads and industrial discharge will benefit this species.
Research needs
Baseline distribution and trend data does not exist for this species. Surveys should target historical but also new streams to better understand its distribution and population status in Massachusetts. Further, surveys are needed to understand the distribution of non-native and potentially invasive crayfish species that may co-occur with spinycheek crayfish at the watershed-scale. Population genetic analysis is needed across watersheds to determine native and potentially introduced populations of spinycheek crayfish. Data can inform species risk assessments.
References
Hobbs H.H. 1989. An illustrated checklist of the American Crayfishes (Decapoda: Astacidae, Cambaridae and Parastacidae). Smithsonian Institution Press, Washington D.C.
Hamr P (2002) Orconectes. In: Holdich DM (ed), Biology of freshwater crayfish. Blackwell Science, Oxford, pp 585- 608
Momot WT (1988) Orconectes in North America and elsewhere. In: Holdich DM, Lowery RS (eds), Biology of freshwater crayfish: biology, management and exploitation. Croom Helm, London and Sydney, pp 262-282
Smith, D. G. 2000. Keys to the freshwater macroinvertebrates of southern New England. Published by author. Sunderland, MA. 243 pp.
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| Date published: | April 9, 2025 |
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