Date of Award

12-2010

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Gayle Zydlewski

Second Committee Member

Teresa Johnson

Third Committee Member

Michael Kinnison

Abstract

Acoustic telemetry is a popular tool among marine and aquatic scientists for studying movements and population dynamics of a variety of species including endangered species such as shortnose sturgeon (Acipenser brevirostrum). I used acoustic telemetry to study movements and abundance of a recently rediscovered population of shortnose sturgeon in the Penobscot River, Maine. Migrations of shortnose sturgeon were generally believed to be restricted to the river and estuary of their natal watershed; however this study has documented previously unknown migration patterns, through coastal environments, and to other rivers along the Gulf of Maine. By documenting the timing and direction of these movements, I identified four migration patterns including in-river migrations and three coastal migrations. I also used acoustic telemetry to quantify the proportion of shortnose sturgeon that migrated seasonally. Observed migration was incorporated into a population model. Seasonal estimates of abundance from the best fit model ranged from 602 (95% CI: 410-911) to 1306 individuals (95% CI: 796-2176), and fluctuated by season. Discovery of coastal movements was possible through cooperation among a network of researchers who used acoustic telemetry in the region. There is currently no formal method for acoustic telemetry users to exchange information; however some researchers have developed informal cooperative groups based on their interactions with other researchers. To learn more about who participates in these informal networks and the interactions that exist among them, I developed and administered an internet survey to acoustic telemetry users in Eastern North America and the Caribbean, and used social network analysis to understand connections among researchers. I identified 150 acoustic telemetry researchers through survey responses, and had a response rate of 66%. I learned that 75% of respondents participated in cooperative telemetry groups. Users of acoustic telemetry identified several tools that would help increase participation in cooperative telemetry groups, including the development of a common system for researcher to exchange information. The documentation of shortnose sturgeon coastal migration has important implications to future management of this and other species. Cooperation among researchers enabled this discovery and future participation of researchers in cooperative networks may help to identify other such undocumented movements.

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