Applied Research Group

Alaska Pacific University
Students participate in research beginning with their first Marine Biology courses, as Freshman or Sophomores.  This page includes undergraduate research in the Behavior & Benthic Ecology group (often related to Alaska Octopus project) as class projects or other work (rather than as a Senior Project or Masters' Thesis).
Diversity and richness among dive sites in Resurrection Bay Alaska.
            B. Elman, J.King, K. Gates, L. Kinion, M. Naschak, M. Perlin, N. Hollenbeck, N. Kozlowski, S. Gouwens, S.  Anderson, D. Scheel.    
ABSTRACT  Comparing species abundance and water flow is a common theme in Marine Biology. The Scientific Diving Class of Alaska Pacific University set out to do just this in May 2012. They analyzed the abundance and water flow of four popular dive
sites in Resurrection Bay Alaska. They expected to find greater species abundance in the sites with higher water flow and less in areas with lesser water flow. To do this they used a swath transect survey to analyze 0.5m by 10m survey at 3 depths at each of these dive sites. Target species where sponges (Porifera), bryazoans (Phoronida), anemones (Cnidarians), and tunicates (Chordata); and mobile invertebrates such as sea stars (Echinodermata) and crabs (Arthropoda). Next they used the Berger-Parker index to compare and generate rank abundance plots. For water flow analysis they used clod cards made of Plaster of Paris to generate water flow reading from grams per hour (g/hr) lost from each clod card. They found dive site Hidden Treasure had the highest water flow and The Grotto had the least, however Shark Tooth had the highest species abundance and The Shackle had the lowest species abundance. They suspect that water flow is not the determining factor for species abundance and suggest further species research, and water flow analysis at these sites and others in the local area for a better understanding what creates high species abundance in marine ecosystems.


Fall 2011 Marine Field Work Class

K. Gates, N. Hollenbeck, M. Perlin, C. Rajčić, G. Walker, C. Creighton, A. Greszczuk, H. Hafner, E. Milano, A. Wilkinson, D. Scheel.  In prep. 2012.  Evidence of tactile camouflage in crabs.
 
ABSTRACT  The giant Pacific octopus, Enteroctopus dofleini, is speculative forager that detects prey by touch. We observed six species of small crabs common in octopus intertidal
Cancer oregonensis burying behavior.  © D. Scheel 2011.
habitat to evaluate the hypothesis that their anti-predator behavior is adapted to escape touch detection by octopuses. We observed Cancer oregonensis, Pugettia gracilis, Oregonia gracilis, Telmessus cheiragonus, Lophopanopeus bellus, and Hapalogaster mertensii and recorded their selection of resting background micro-habitat, response to visual and touch disturbance, and density in proximity to octopus habitat on tactilely matching or contrasting backgrounds. O. gracilis and P. gracilis decorate their carapaces to varying degrees; and we found that P. gracilis but not O. gracilis chose background habitat that texturally matched carapace decoration in the absence of visual cues. C. oregonensis, L. bellus, and T. cheiragonus do not decorate their carapace, although T. cheiragonus is covered in fine bristles and H. mertensii carapace and legs are covered in coarse stiff bristles. Except for O. gracilis and H. mertensii, more crabs of each species occurred on visually than texturally matching backgrounds. However, the density of the most abundant crab species (P. gracilis and L. bellus) on texturally-contrasting backgrounds was not depressed near to octopus dens compared to far from them, as we had expected on a hypothesis of tactile predation reducing Finally, we hypothesized that visually camouflaged crabs should freeze on visual disturbance and flee when touched; while the reverse would be expected of crabs maintaining crypsis to a tactile forager. The frequency of immobile, Aufbaum reflex (defensive posture) and retreat behaviors varied across species in response to visual and tactile disturbance. Except for C. oregonensis (which frequently  retreated slowly and incrementally buried itself), immobility was the most common response to visual disturbance. Thus all crabs appear adapted to visual predators. However, retreat or Aufbaum reflex behavior was proportionally more common on touch disturbance than visual for some species (P. gracilis, L. bellus, T. cheiragonus) while immobility remained the dominant response for other species (O. gracilis, H. mertensii). The habit of O. gracilis to completely cover its carapace and legs with algal and sessile invertebrate decoration and the stiff bristles of H. mertensii make these two crabs the most texturally similar to background environments, and their continued immobility on touch disturbance indicates reliance on immobility for crypsis during tactile predator encounters. Thus, our experiments demonstrate that at least some crabs are capable of using non-visual information to select backgrounds matching their carapace texture, and exhibit a behavioral strategy of immobility during tactile encounters with predators.
Keywords: Enteroctopus dofleini, Lophopanopeus bellus, Cancer oregonensis, Telmessus cheiragonus, Pugettia gracilis, Oregonia gracilis, Hapalogaster mertensii, tactile camouflage, crypsis, escape syndrome Small crabs fall prey to an array of predators (fish: Beer 1959, gulls: Coulson & Coulson 1993, Hazlett et al.
Comments