The Behavior and Holding Strength of Darts Used to Attach Pop-up Satellite Tags, Through the Use of Pull Out Testing
Large pelagic fish are an area of mystery; through the use of Pop-up Satellite Archival Tags (PSATs) more information can be obtained. PSATs are used for large pelagic fish data acquisition and connect information to a satellite data base. Failure by the dart anchors used to hold PSATs underneath the flesh of large pelagic fish has resulted in the loss of data and unretumed PSATs from the wild. Testing the holding force needed to anchor a PSAT into a large pelagic fish provides useful information about the behavior of the darts used and why failure is occurring. Four darts commonly used for tagging large pelagic fish were tested during this experiment: the eight prong umbrella dart, two and four prong billfish darts, and the Mike Musyl flopper dart design. The umbrella darts and the two and four prong darts were tested ten different times and the Musyi dart was tested three different times. A custom made Pull Out Apparatus (POA) applied a constant speed to each of the darts pulled out of the ballistics gelatin used as a standard medium made to simulate pelagic fish flesh. The four groups of darts all exhibited similar behaviors within the dart type. Similar pull out forces, physical damages on the dart and deformation on the gel were seen within the four dart types. A comparison between the four different dart types resulted in the PIMA four pronged dart having a stronger holding force than the PIMA two pronged dart, and the eight pronged umbrella dart exhibited a stronger holding force over time than the PIMA darts. The PIMA darts had the strongest base holding force compared to the other two darts. This experiment creates a standard and repeatable testing mechanism that can be used to make improvements on future darts manufactured for PSATs.
Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant
- The behavior and holding strength of darts used to attach pop-up satellite tags, through the use of pull out testing (2006). Stephanie Kloek, Kaitlin Hartman and Christopher Kirkland. Advisors: Ken Baldwin and Nuno Fragoso.