EFFECTS OF FLOW VELOCITY AND SETTLEMENT LOCATION ON GROWTH RATES OF EARLY JUVENILES OF THE PEDUNCULATE BARNACLE, POLLICIPES POLYMERUS, SOWERBY 1833
| dc.contributor.author | Everson, Hannah N. | |
| dc.date.accessioned | 2021-12-04T01:21:03Z | |
| dc.date.available | 2021-12-04T01:21:03Z | |
| dc.date.issued | 2021-11-10 | |
| dc.description | 18 pages | en_US |
| dc.description.abstract | The intertidal lepadomorph barnacle, Pollicipes polymerus, is known for its propensity to aggregate in rosette-shaped or irregular clusters. The gregarious lifestyle is ensured by the species’ settlement preference. Cyprids of P. polymerus settle almost exclusively on the peduncle of adult conspecifics, while settlement in cracks and crevices and on acorn barnacles is rare. For gregarious settlement behavior to evolve and persist, individuals should gain some benefit that would otherwise not be achieved with a solitary lifestyle - such as defense against predators (Riipi et al. 2001) or to facilitate cross-fertilization (Wu 1981) Due to increasing demand for P. polymerus in culinary markets, the gregarious settlement behavior makes them particularly susceptible to overharvesting. This study examines whether gregarious settlement results in higher growth rates of juveniles compared to growth of solitary individuals. I asked if and how P. polymerus gains in overall fitness from gregarious settlement. I address two questions: 1) Is the growth rate of early juveniles dependent on the velocity of water in which they feed? and 2) Does settlement on conspecifics benefit early juveniles by increasing growth rate? Two treatment groups (solitary and gregarious) were studied, with individuals ranging in size from 1mm - 3mm rostro-carinal length. An apparatus, utilizing a rotating disc, was constructed to create a range of experimental velocities. For two trials carried out in a marina environment (trial 1 and 2), growth rates ranged from 0.1mm - 1.2mm/wk at any given velocity. For two trials in a tank environment (trials 3 and 4) individual growth never exceeded 0.6mm/wk. Overall results indicate that neither current velocity nor settlement location had consistent effects on early juvenile growth rates. In the tank environment, where food concentrations were lower, velocity had a significant negative effect on the growth rate of gregarious but not solitary juveniles. In only 1 of 4 trials, settlement on a conspecific had a significant positive effect on average juvenile growth. The absence of consistent trends within and across trials together with few significant results indicate that velocity and settlement location for early juveniles may not be primary factors in gregarious settlement of this barnacle. Other factors or these factors at different life stages may account for settlement behavior. My findings also suggest that aquaculture of these barnacles does not require specific flow speeds or adult substrata to cultivate newly settled barnacles. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/26919 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of Oregon | en_US |
| dc.rights | Creative Commons BY-NC-ND 4.0-US | en_US |
| dc.title | EFFECTS OF FLOW VELOCITY AND SETTLEMENT LOCATION ON GROWTH RATES OF EARLY JUVENILES OF THE PEDUNCULATE BARNACLE, POLLICIPES POLYMERUS, SOWERBY 1833 | en_US |
| dc.type | Thesis / Dissertation | en_US |