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Competition and predator-prey interactions in aquatic ecosystems

Project Abstract: 
Sensory ecology is designed to understand how organisms use environmental cues and signals to extract meaningful information about their environment. My lab focuses primarily on the role of chemical cues and signals in the aquatic realm to mediate these interactions. We are focusing on competition and predator-prey interactions between fish species as well as between fish and invertebrates. Our system includes largemouth bass, pumpkinseed, bluegill, and crayfish along with macrophytes, snails, and detritus as food sources. Using the stream lab and artificial streams, we can create mesocosms to isolate different sensory stimuli to understand the role of information in mediating ecological interactions.
Status of Research Project: 
Years Active: 
Four flow-through stream mesocosms (162.56 x 121.92 x 40.64 cm: l x w x d) were constructed using cinderblocks lined with 4-mil black polyethylene sheeting (Figure 1). Water was delivered to each of the mesocosms by a 208 L plastic drums which served as a constant head tank. The constant head tank was fed with unfiltered water from the East Branch of the Maple River and the same water was used to house the crayfish and bass. Water entered the drums via 7.6 cm PVC pipes which were fitted with nylon stockings to filter out macroinvertebrates. Water was fed from the drum to mesocosms through two garden hoses per mesocosm for a total of eight hoses on a single drum. The garden hoses had diameters of 1.9 cm (flow rate = 0.1 ± 0.05 L/sec [mean ± SEM]). Largemouth bass are present within the Maple River, but previous work has shown that using unfiltered and unaltered Maple River water in control situations is applicable as a control. The concentration of predatory cues as altered in the experimental set up results in a significant change in anti-predatory behavior (Beattie and Moore, 2018). Each mesocosm was comprised of two identically sized sections: a predator arena and a prey arena. Predator arenas were located upstream of the prey arena and were covered with mesh sheeting to prevent bass escape. The predator and prey arenas of all mesocosms were each measured at 81.28 x 60.96 x 40.64 cm (l x w x d). The predator section had no substrate, while the prey section was lined with a sand substrate to a depth of 7.6 cm. This same construction technique has been used successfully in previous predator-prey experiments (Wood et al. 2018; Wagner and Moore 2022). Water flowed into the upstream predator section of each mesocosm before overflowing through a screened opening (28 x 12 cm opening with 1 x 1 mm screening) in a partial wall into the downstream prey section. The wall served to separate the prey from the predator and removed any visual or mechanical signals (Wood and Moore 2020). A wooden frame sat on top of the mesocosms and held an infrared DVR camera (Zosi ZR08ZN10) 1.1 m above the water surface of each mesocosm to record crayfish nocturnal behaviors. Each camera was set at a frame rate of 30 fps which is high enough to capture crayfish movement (Moore et al. 2021). A single low intensity red light bulb (Great Value brand: Model A19045 LED Lamp, 9 W, 145 mA, 120 V, 60 Hz, RED) was used to illuminate two of the mesocosms that allowed analysis of the crayfish behavior. The presence of red light does not impact crayfish behavior (Cronin and Goldsmith 1982; Bruski and Dunham, 1987).