Density-dependent habitat use and growth of an estuarine fish.
Author(s): Bacheler, Nathan M., Jeffrey A. Buckel, and Lee M. Paramore.
NCCOS Center: CCFHR (http://coastalscience.noaa.gov/about/centers/ccfhr)
Center Team: NMFS
Publication Type: Journal Article
Journal Title: Canadian Journal of Fisheries and Aquatic Sciences
Date of Publication: 2012
Reference Information: 69(11):
Keywords: CCFHR; NOAA Fisheries; Estuaries; Resource and land use; Density dependence; Estuary; Food limitation; Spatial distribution; Competition
Abstract: Density dependence can strongly influence population dynamics by either stabilizing or destabilizing population size through negative or positive feedback controls operating over different spatial and temporal scales. While many species in a variety of different ecosystems have been shown to exhibit density dependence, the topic has received less attention in estuaries where environmental variability and larval supply are often considered to be the primary drivers of population dynamics. We used multiple long-term, fishery-independent datasets and a unique modeling approach to test the hypothesis that juvenile red drum Sciaenops ocellatus exhibit density-dependent habitat use and growth rates in estuaries in North Carolina, USA. Annual individual growth rates of age-0 and age-1 red drum were generally negatively related to the abundance of their own age classes, but evidence of density-dependent growth rates for age-2 red drum was weak to nonexistent. Additionally, age-1 red drum exhibited density-dependent habitat use after accounting for environmental and landscape variables, disproportionately increasing northward and coastward in the study area at high abundance and retracting to the southwest at low abundance. Age-2 red drum habitat use was influenced more by age-1 than age-2 abundance, suggesting that negative interactions occur among cohorts of juvenile red drum. Red drum distribution in estuaries is influenced by both local density-independent factors (e.g., depth) and large-scale density-dependent factors (e.g., overall age-1 abundance). Changes in spatial distribution of red drum when overall abundance was high did not overcome density-dependent effects on individual growth rates, setting up potential negative feedbacks on population growth.
Location URL: http://www.nrcresearchpress.com/doi/abs/10.1139/f2012-098