Mark-Recapture Explained

Jan 14, 2016

Mark-Recapture ExplainedMark and recapture is a method commonly used in ecology to estimate an animal population's size. A portion of the population is captured, marked, and released. Later, another portion is captured and the number of marked individuals within the sample is counted. Wikipedia. Marked individuals within the second sample are termed 'recapture'.
 Here is an example with ants. 
In my project, "capturing" a dolphin consisted of taking a good quality picture of its dorsal fin. Many dolphins have nicks and notches on their dorsal fin, providing a natural way of identifying them individually.
In its simplest form, population size N is calculated using the formula below:
 N = marked (1st sample) * captured (2nd sample) / recapture (2nd sample)

Mark Recapture

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About This Project

Where do northern SC bottlenose dolphins go? Comparing dorsal fins to understand migration patterns.

Coastal Carolina University

In a two-year study, we found seasonal residents but no year-round dolphins off the coast off northern South Carolina. This area is described to include four overlapping stocks (one migratory, one coastal and two estuarine), yet stock boundaries and seasonal movements are not well defined. I intend to discover where northern SC dolphins go by comparing dorsal fin catalogs to neighboring areas. Defined boundaries and movements helps managers assess threats and plan to prevent population decline.