Home > Explore Data & Reports > Assessing movements of three buoy line types using DSTmilli loggers: Implications for entanglements of Bottlenose dolphins in the crab pot fishery


McFee, W.E., P.L. Pennington, L.G. Burdett, J.W.B. Powell, J.H. Schwacke, and F.E. Dockery. 2007. Assessing movements of three buoy line types using DSTmilli loggers: Implications for entanglements of Bottlenose dolphins in the crab pot fishery. NOAA Technical Memorandum NOS NCCOS 67. Charleston, SC. 58 pp.

Data/Report Type:

NOAA Technical Memorandum

Related Project(s):

No posts found.


A study was conducted in October 2006 in the Charleston, South Carolina area to test the movements of three different buoy line types to determine which produced a preferred profile that could reduce the risk of dolphin entanglement. Tests on diamond-braided nylon commonly used in the crab pot fishery were compared with stiffened line of Esterpro and calf types in both shallow and deep water environments using DSTmilli data loggers. Loggers were placed at intervals along the lines to record depth, and thus movements, over a 24 hour period. Three observers viewed video animations and charts created for each of the six trial days from the collected logger data and provided their opinions on the most desirable line type that fit set criteria. A quantitative analysis (ANCOVA) of the data was conducted taking into consideration daily tidal fluctuations and logger movements. Loggers tracking the tides had an r2 value approaching 1.00 and produced little movement other than with the tides. Conversely, r2 values approaching 0.00 were less affected by tidal movement and influenced by currents that cause more erratic movement. Results from this study showed that stiffened line, in particular the medium lay Esterpro type, produced the more desirable profiles that could reduce risk of dolphin entanglement. Combining the observer’s results with the ANCOVA results, Esterpro was chosen nearly 60% of the time as opposed to the nylon line which was only chosen 10% of the time. ANCOVA results showed that the stiffened lines performed better in both the shallow and deep water environments, while the nylon line only performed better during one trial in a deep water set, most probably due to the increased current velocities experienced that day.

Note to readers with disabilities: Some scientific publications linked from this website may not conform to Section 508 accessibility standards due to the complexity of the information being presented. If you need assistance accessing this electronic content, please contact the lead/corresponding author, Primary Contact, or nccos.webcontent@noaa.gov.

Explore Similar Data/Reports
No posts found.


NCCOS delivers ecosystem science solutions for stewardship of the nation’s ocean and coastal resources to sustain thriving coastal communities and economies.

Stay Connected

Sign up for our quarterly newsletter or view our archives.

Follow us on Social

Listen to our Podcast

Check our our new podcast "Coastal Conversations"