IMIS - Marine Onderzoeksgroepen

The dolphins appear as individuals or pairs in April and May, with group size increasing in June to a peak mean of 29 animals sighted per encounter. Group size then decreases in October and November. Probability of encountering dolphins ranges from 0% during the winter and early spring to over 80% in July, tapering off towards fall. Activity patterns show greatest diversity in July and August, with travel constituting the main activity early and late. Despite a peak of births in the area in May-June, there is little mating until July, with the incidence of sexual activity peaking in September.
Purpose: To better understand the seasonality and behavior of bottlenose dolphins in the lower Chesapeake Bay.

Data were originally collected by Mr. Kevin Foss at Christopher Newport University during field seasons from 2000-2006. Data were subsequently acquired by the U.S. Navy in 2013.
[2015-03-24] A few records had a wrong animal count of zero. The value is replaced with a blank representing species presence only. These data are the result of small boat transects with focal group follows, so that sightings were recorded at regular intervals. Therefore, there may be sightings of the same individuals at different times.
Records that originally estimated a range for the number of adults were attributed with the median number to be conservative.
Three records on land were excluded.