Harvesting, predation and competition effects on a red coral population

• Published in: Netherlands Journal of Sea Research [NETH. J. SEA RES.]. 1992 Vol. 30; pp. 219 - 228
• Main Authors: Abbiati, M., Buffoni, G., Caforio, G., Di Cola, G., Santangelo, G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Den Helder Elsevier B.V 1992; Netherlands Institute for Sea Research
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Corallium rubrum; Demecology; Fundamental and applied biological sciences. Psychology; Marine; Protozoa. Invertebrata; Mediterranean Sea; West Mediterranean; MED, Ligurian Sea; MED, Italy, Liguria; Population exploitation; Population structure; Perturbation; Marine environment; Coelenterata; Simulation; Cnidaria; Population recruitment; Intraspecific competition; Density dependence; Population dynamics; Simulation model; Predation; Invertebrata; Colonization
• ISSN: 0077-7579
• DOI: 10.1016/0077-7579(92)90060-R

A Corallium rubrum population, dwelling in the Ligurian Sea, has been under observation since 1987. Biometric descriptors of colonies (base diameter, weight, number of polyps, number of growth rings) have been recorded and correlated. The population size structure was obtained by distributing the colonies into diameter classes, each size class representing the average annual increment of diameter growth. The population was divided into ten classes, including a recruitment class. This size structure showed a fairly regular trend in the first four classes. The irregularity of survival in the older classes agreed with field observations on harvesting and predation. Demographic parameters such as survival, growth plasticity and natality coefficients were estimated from the experimental data. On this basis a discrete nonlinear model was implemented. The model is based on a kind of density-dependent Leslie matrix, where the feedback term only occurs in survival of the first class; the recruitment function is assumed to be dependent on the total biomass and related to inhibiting effects due to competitive interactions. Stability analysis was applied to steady-state solutions. Numerical simulations of population evolution were carried out under different conditions. The dynamics of settlement and the effects of disturbances such as harvesting, predation and environmental variability were studied.