Data from: Empirical verification of feeding selectivity of larval and juvenile pelagic fishes using in situ zooplankton communities
Data files
Jun 10, 2024 version files 20.06 KB
Abstract
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.
README: 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.
Methods
Data were collected from feeding experiment using larval japanese anchovy and juvenile chub mackerel.