Date of Award

5-2026

Access Control

Open Access

Degree Name

Master of Arts (MA)

Department

Biology

Advisor

Christopher Pennuto Ph.D.

Department Home page

https://biology.buffalostate.edu/

First Reader

Christopher Pennuto, Ph.D.

Second Reader

Gavin Leighton, Ph.D.

Third Reader

Robert Warren, Ph.D.

Abstract

Aquatic invasive species pose a significant threat to native biodiversity, water quality, and local economies. The Laurentian Great Lakes are especially at risk with over 180 established non-native species. In particular, the red swamp crayfish (Procambarus clarkii) is a recent invader to the Lake Erie eastern watershed and requires sustained management to prevent its spread further into the region. This thesis explores a multi-faceted approach to managing this species via a habitat manipulation study and a laboratory behavior experiment.

I assessed the outcomes of winter stream dewatering on population catch per unit effort (CPUE), mean animal size, and population sex ratio in a small, man-made stream system near Buffalo, NY. Crayfish catch per trap night (CPUE), animal size, and sex ratio were compared following a winter dewatering manipulation. The study stream was dewatered from December to April, in the winter of 2024-2025, exposing crayfish to sub-freezing temperatures. Results showed a reduction in crayfish CPUE post-dewatering in the stream habitat, while catch remained stable in the adjacent pond. Surviving crayfish in the stream exhibited an increase in body size between years, likely due to density-dependent effects from reduced intraspecific competition. The population sex ratio remained unchanged between pre- and post-dewatering years. These results suggest that winter dewatering can alter red swamp crayfish populations in cold climates outside of their native range.

I also assessed whether crayfish transferred learned predator scents to unfamiliar fish species under varying conditions of food availability and how this differed between native white river crayfish (Procambarus acutus) and invasive red swamp crayfish. Crayfish were conditioned to fear largemouth bass (Micropterus salmoides) and then exposed to control, largemouth bass, bullhead catfish (Ameiurus melas) or rock bass (Ambloplites rupestris) scents in experimental arenas. Time outside of refuge, movement, and location in the arena were all documented to assess crayfish responses to predator and food treatment. Contrary to my hypothesis, there was no clear difference between crayfish species when exposed to different predator scents, however white river crayfish were generally more bold than red swamp crayfish. Exposure to largemouth bass and bullhead catfish reduced bold behavior in both species, whereas exposure to rock bass resulted in increased bold behavior. Time outside of refuge decreased following exposure to largemouth bass, whereas exposure to the other treatments and control decreased time outside of refuge. These results suggest that transference of learned predator avoidance may not differ between red swamp crayfish and white river crayfish, and, thus, may not play an important role in invasion success.

Together, these studies highlight the potential of exploiting life-history vulnerabilities and understanding behavioral mechanisms to improve management of red swamp crayfish. Winter stream dewatering may be a viable management strategy in cold climates. However, no clear differences were observed in predator avoidance between invasive red swamp crayfish and native white river crayfish after exposure to a range of predator and food scents.

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