Dynamic self‐thinning model for sessile animal populations with multilayered distribution

Abstract

The main drawback of the traditional self-thinning model is how time is handled. Self-thinning (ST) has been formally recognized as a dynamic process, while the current ST models have not included the temporal effect. This restricts the analysis to the average competitive behaviour of the population and produces a biased estimation of the self-thinning parameters. In this study, we extend the dynamic ST model introduced by Roderick and Barnes (2004) to the analysis of multilayered sessile animal populations. For this purpose, we incorporate the number of layers and the density per layer into the dynamical approach. The performance of the dynamic model was checked and compared with the classical ST model through the analysis of mussel populations grown at different density treatments. Unlike the traditional model, the dynamical approach detected the effect of culture density on the competitive behaviour of individuals and allowed to analyse the temporal evolution of intraspecific competition by estimating the ST exponent trajectory. Moreover, this approach provided an ecological interpretation of any possible value of the ST exponent. Thus, our results support the use of the dynamic model in the analysis of selfthinning in sessile animal multilayered populations. The estimation of the ST exponent trajectory reflects the dynamic nature of the ST process, providing a more realistic description of population dynamics than the traditional model.

A bioeconomic approach to optimize mussel culture production

“…This study shows that both parametric (SFPF) and nonparametric (Malmquist indices) approaches reflect the effect of mussel population dynamics (intraspecific competition, mussel growth and mortality) on production. Population dynamics were previously described on the same data set by Cubillo et al (2012b) and Fuentes-Santos et al (2014). The former found a negative effect of stocking rate on mussel growth rates, and the later found significant mussel losses at higher density (>500 ind m À1 ), being 1150 ind m À1 the treatment with the highest mortality.…”

“…() and Fuentes‐Santos et al . (). The former found a negative effect of stocking rate on mussel growth rates, and the later found significant mussel losses at higher density (>500 ind m −1 ), being 1150 ind m −1 the treatment with the highest mortality.…”

“…indicated an underuse of the available resources. The relative efficiency of 1150 ind m À1 , which suffered the strongest competition effects on mussel growth and survivorship (Cubillo et al 2012a;Fuentes-Santos et al 2014), indicates that this density exceeded the carrying capacity of the rope, with the subsequent economic losses. Mussel mortality also implies a higher organic loading beneath culture leases that may alter the physical and chemical conditions of the bottom sediments and affect benthic biodiversity (Callier et al 2009;Soto 2009;Ysebaert et al 2009).…”

“…; Fuentes‐Santos et al . ), indicates that this density exceeded the carrying capacity of the rope, with the subsequent economic losses. Mussel mortality also implies a higher organic loading beneath culture leases that may alter the physical and chemical conditions of the bottom sediments and affect benthic biodiversity (Callier et al .…”

Efectos de la densidad de siembra y el desdoble sobre el crecimiento y la supervivencia en un cultivo suspendido experimental del mejillón Mytilus platensis d’Orbigny, 1842, en el Golfo San Jorge, Argentina

“…m -1 ) en el desarrollo de un cultivo suspendido de mejillón (Alunno-Bruscia et al 2000;Cubillo et al 2012a;Pérez-Camacho et al 2013;Bordon et al 2014). Altas densidades iniciales generan competencia por espacio y/o alimentos (Fréchette y Lefaivre 1990), así como mortalidad asociada a la competencia intraespecífica a medida que los animales se desarrollan (Fréchette et al 1996;Fréchette y Bacher 1998;Alunno-Bruscia et al 2000;Guiñez 2005;Fréchette et al 2011;Fuentes-Santos et al 2014). Se han registrado también efectos densodependientes sobre el desarrollo individual y el aumento en las pérdidas por desprendimiento (Lauzon-Guay et al 2005a;Cubillo et al 2012aCubillo et al , 2012b.…”