Open AccessDensity-dependent consequences of size-selective induced life-history changes to population fitness in medaka (Oryzias latipes)
Author(s) -
Charlotte Evangelista,
Leif Asbjørn Vøllestad,
Beatriz Díaz Pauli,
Éric Édeline
Publication year - 2020
Publication title -
canadian journal of fisheries and aquatic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 153
eISSN - 1205-7533
pISSN - 0706-652X
DOI - 10.1139/cjfas-2019-0406
Subject(s) - oryzias , biology , population , density dependence , population size , longevity , growth rate , selection (genetic algorithm) , truncation (statistics) , population density , life history , zoology , fish <actinopterygii> , ecology , demography , statistics , mathematics , genetics , fishery , geometry , artificial intelligence , sociology , computer science
There is an increasing concern about the potential for size-selective harvest to impair population persistence. Yet little is known about the relative contribution of the evolutionary (shifts in life history) and demographic effects (decreased population density and size truncation) of harvesting to changes in fitness. Using medaka (Oryzias latipes), we experimentally investigated the fitness consequences of antagonistic size-dependent selection under contrasted levels of density (low versus high) and size structure (uniform versus truncated). The size-dependent selection generated large- and small-breeder lines with fast growth and late maturity versus slow growth and early maturity life histories, respectively. A decrease in density had a positive effect on almost all fitness components, while size truncation only had a positive effect on fish growth. Small-breeder fish grew slower and had a greater probability of reproducing, at least when considering small-sized females. The number of larvae and juveniles did not differ between the two lines. Finally, the positive effect of decreased density on population asymptotic growth rate was less pronounced in small-breeders than in large-breeders of medaka. These findings stress the importance of considering the ramifications of fishing-adapted life history to population persistence in the light of density-dependent population dynamics.