DOI: 10.5061/dryad.82gg4
title: Data from: Modeling of the larval response of green sea urchins to thermal stratification using a random walk approach

description: Larval transport in the ocean can be affected by their vertical position
 in the water column. In biophysical models that are often used to predict
 larval horizontal dispersal, generally larval vertical positions are
 either ignored or incorporated as static parameters. Here, we evaluate the
 ability of one dimensional random walk based model to predict larval
 vertical distribution of Strongylocentrotus droebachiensis in response to
 thermal stratification. Vertical swimming velocities were recorded at
 various temperatures and used to parameterize the model. Data from a
 previous laboratory study on the effects of thermal stratification on
 larval vertical distribution of S. droebachiensis were compared to the
 model results to evaluate the predictive ability of the model. The model
 predicts general trends in vertical distribution fairly well, but has a
 systematic bias which can be explained by un-quantified larval behaviors
 at the boundaries of the experimental water column. Overall, our
 behavioral model successfully reproduces the mechanism which regulates
 larval vertical distribution in response to thermal structure.
 Collectively, the findings suggest that simple behavioral models
 parameterized using simple lab experiments can prove useful in estimating
 the vertical distributions of invertebrate larvae in the laboratory and
 likely in the ocean. Such models can then be linked to bio-physical models
 to more accurately predict larval dispersal.
description: autocorrelationTo quantify larval swimming, still images were extracted every 2.5 s for the entire 60-min video recording, and larval positions (x, z co-ordinates) were measured using ImageJ. To obtain w and s for each replicate, all individuals in focus from 20 pairs of frames (frames in a pair were 2.5 s apart) were used, each pair being separated by 3-min intervals.To analyze the temporal covariance of vertical swimming velocities, the position of 20 randomly selected larvae (1 every 3 min) was recorded over time (t) for as long as possible (i.e. until it crossed paths with another larva, or moved out of frame or out of focus). The covariance of each larva's vertical swimming velocity was calculated for time lags from 0 to 60 s. Data set includes larval rearing temperature (°C), experimental temperature (°C), replicate number, larvae number, x (horizontal) and z (vertical) positions within the frame (mm), time since introduction of larvae (min:s:ms or decimal s), and vertical swimming velocities (mm s-1)velocityTo quantify larval swimming, still images were extracted every 2.5 s for the entire 60-min video recording, and larval positions (x, z co-ordinates) were measured using ImageJ. To obtain w and s for each replicate, all individuals in focus from 20 pairs of frames (frames in a pair were 2.5 s apart) were used, each pair being separated by 3-min intervals. Data set includes larval rearing temperature (°C), experimental temperature (°C), replicate number, time since introduction of larvae (min:s:ms or decimal s), larvae number, x (horizontal) and z (vertical) positions within the frame (mm), and vertical swimming velocities (mm s-1)