Data from: Common bottlenose dolphin (Tursiops truncatus) behavior in an active narrow seaport

The Galveston Ship Channel (GSC) is a narrow, congested waterway that
supports large-scale shipping, commercial fishing, dolphin tourism, and
recreation. Human activity and common bottlenose dolphins (Tursiops
truncatus) converge in the GSC with potentially negative consequences on
the dolphins. Elevated land-based tracking and behavioral observation of
dolphins and vessels were conducted along the GSC in June-August 2013
using a digital theodolite. Positional information was used to calculate
dolphin movement patterns and proximity to vessels. Log-likelihood ratio
and Chi-square contingency tests were used to assess behavioral states,
and generalized additive models were used to analyze movement patterns
(i.e., swimming speed, reorientation rate, and linearity) relative to
endogenous and exogenous factors and vessel presence. Dolphins regularly
use the GSC to forage (57% of observed behavioral states) and socialize
(27%), and it is not a travel corridor for accessing other favorable sites
(traveling=5%). Dolphin behavior varied significantly based on time of
day, group size, calf presence, and general boat presence. When boats were
present, the proportion of time dolphins spent socializing and foraging
was significantly less than expected by chance. Swimming speeds increased
significantly in the presence of small recreational boats,
dolphin-watching tour boats, shrimp trawlers, and when tour boats and
shrimp trawlers were both present. Reorientation rate increased
significantly in the presence of tour boats and trawlers. Dolphin
behavioral responses to vessel presence may result in decreased energy
consumption due to disrupted foraging activity. Without proper management,
the observed behavioral changes may be detrimental to individuals within
this population in the short term, with potential long-term consequences
to health and survivorship.