DOI: 10.5061/dryad.hmgqnk9qd
title: Data from: Empirical verification of feeding selectivity of larval and juvenile pelagic fishes using in situ zooplankton communities

description: Most studies on the feeding ecology of larvae and juveniles of
 commercially important pelagic fishes have used field-based approaches.
 However, due to possible biases related to net sampling, it is uncertain
 whether the results obtained from those studies truly represent the
 situation of live fish in the sea. Here we investigated the feeding
 ecology of pelagic fishes through a laboratory experiment minimizing the
 biases inherent in field net sampling. In the experiment, hatchery-reared
 juvenile chub mackerel (Scomber japonicus) and larval/juvenile Japanese
 anchovy (Engraulis japonicus) were fed with wild-caught zooplankton
 assemblages collected from around Hakatajima Island in the Seto Inland
 Sea, Japan. The relationships between fish size and prey number in the
 gut, and the selectivity on each prey organism were determined. As a
 result, in both species, prey number and size increased with body size,
 and the fish showed strong selectivity for crustaceans including
 copepodites and adults of copepods. Our data has also clearly indicated
 that both species can selectively prey on preferred foods that are rare
 while avoiding non-preferred foods that are abundant. These results, which
 substantially accord with reports from previous field studies, will not
 only help field scientists make a convincing interpretation of their data,
 but also open the possibility of further laboratory studies on detailed
 mechanisms of the feeding selectivity of larval/juvenile pelagic fishes.
description: Data were collected from feeding experiment using larval japanese
 anchovy and juvenile chub mackerel.
description: # Empirical verification of feeding selectivity of larval and juvenile
 pelagic fishes using in situ zooplankton communities Description of
 uploaded data mackerel_juvenile_size_prey_relationship.csv
 anchovy_larvae_size_prey_relationship.csv These files include data of;
 individual ID (as id), the standard length of individuals in mm (as
 Standard_length_mm), taxonomical category of the ingested prey (as
 taxonomical_category), length and width of each prey item, the condition
 of each preys (as class; C: the morphology of prey individuals were almost
 completely maintained, PB: morphology was partly broken but still could
 measure width and length precisely, B: morphology has largely broken so
 could not measure width and length), prey numbers in the gut of each
 tested fishes and trial (representing from which of three trials samples
 were obtained from). These data were used for determining the i)
 relationships between prey number in the gut and standard length and ii)
 relationships between prey size (length and width) in the gut and standard
 length of each species. Four following codes were used for above mentioned
 analysis for both species. mackerelSL_preyNUMBER_GLM.R
 mackerelSL_preySIZE_GLMM.R anchovySL_preyNUMBER_GLM.R
 anchovySL_preySIZE_GLMM.R To generate (a) in Figures 4 and 5, following
 data were used. anchovy_prey_length_inWATER.csv
 mackerel_prey_length_inWATER.csv To generate (b) and (c) in Figures 4 and
 5, following data were used. Anchovy_preySelectivity_waterRatio.csv
 Mackerel_preySelectivity_waterRatio.csv ratio in these files represents
 prey selectivity of each prey category for group=selectivity, and
 represents ratio of each prey category contained in the experimental water
 for group=water.