Harvesting in discrete-time predator-prey systems

Area of Science:

• Ecology
• Fisheries Science
• Mathematical Biology

Background:

• Fisheries often involve interacting species with seasonal recruitment in temperate and boreal oceans.
• Discrete-time difference-equation models are useful for analyzing such exploited systems.

Purpose of the Study:

• To examine the dynamic behavior of discrete-time models for exploited predator-prey systems.
• To contrast the stability and dynamic properties of aggregate production and age-structured models under harvesting.
• To define the joint effects of harvesting and interspecific interactions on system stability.

Main Methods:

• Utilized discrete-time difference-equation models.
• Compared an aggregate production model with an age-structured model.
• Analyzed the impact of harvesting juveniles versus adults on system dynamics.

Main Results:

• Harvesting can stabilize exploited predator-prey systems, particularly when juveniles are harvested.
• The magnitude of predator-prey interaction significantly affects stabilization levels.
• Harvesting adults only can be destabilizing, leading to complex dynamics, with stronger interactions expanding stable parameter space.
• Exploitation reduces population growth rates; this effect is amplified in prey with high predation mortality.

Conclusions:

• Harvesting strategies, including targeting juveniles, can influence the stability of exploited predator-prey systems.
• Predator-prey interactions are critical in determining sustainable exploitation levels.
• Fisheries management must consider trade-offs between yield, variability, and the role of interspecific interactions.