DOI: 10.5061/dryad.x95x69pkf
title: Data from: Evolutionary impact of size-selective harvesting on shoaling behavior: Individual-level mechanisms and possible consequences for natural and fishing mortality

description: Intensive and size-selective harvesting is an evolutionary driver of
 life-history as well as individual behavioral traits. Yet, whether and to
 what degree harvesting modifies the collective behavior of exploited
 species is largely unknown. We present a multi-generation harvest
 selection experiment with zebrafish (Danio rerio) as a model
 species to understand the effects of size-selective harvesting on shoaling
 behavior. The experimental system is based on a large-harvested (typical
 of most wild capture fisheries targeting larger size classes) and
 small-harvested (typical of specialized fisheries and gape-limited
 predators targeting smaller size classes) selection lines. By combining
 high resolution tracking of fish behavior with computational agent-based
 modeling we show that shoal cohesion changed in the direction expected by
 a trade-off between individual vigilance and the use of social cues. In
 particular, we document a decrease of individual vigilance in the
 small-harvested line, which was linked to an increase in the attention to
 social cues, favoring more cohesive shoals. Opposing outcomes were found
 for the large-harvested line, which formed less cohesive shoals. Using the
 agent-based model we outline possible consequences of changes in shoaling
 behavior for both fishing and natural mortality. The changes in shoaling
 induced by large size-selective harvesting may decrease fishing mortality,
 but increase mortality by natural predators. Our work suggests an insofar
 overlooked evolutionary mechanism by which size-selective harvesting can
 affect fishing and natural mortality of exploited fish.
description: This dataset contains data
 from a shoaling trials performed with groups of 8 adults zebrafish
 described in the paper: "Sbragaglia et al. (2021) Evolutionary impact
 of size-selective harvesting on shoaling behavior: Individual-level
 mechanisms and possible consequences for natural and fishing
 mortality". The investigates the effects of
 size selective mortality on shoaling behavior. The experimental lines of
 zebrafish have been exposed to directional size-selection for 5
 generations and then selection has been halted for further 8 generations.
 The results presented here are related to F13. We first
 tracked shoaling behavior at 150 and 190 days post fertilizatoin with
 Ethovision in order to measure group-level variable and estimates
 repeatability of shoaling bhavior between two different ontogenetic
 period. Then, we tracked shoaling behavior at 190 using
 IDtracker in order to measure individual behavior within the shoal and
 estimates the impact of size-selective harvesting on shoal cohesion,
 individual speed, and burst rate and inform an agent-based model that has
 been used to understand the effect of vigilance on shoaling behavior. The
 model has also been used to perform simulations to assess the impact of
 size selective harvesting on fishing and natural mortality.
description: The readme file contains an explanation of each of the variables
 in the dataset, its measurement units. n/a =  values not available.
 Information on how the measurements were done can be found in the
 associated manuscript referenced above.