How Wayfinders Modulate Dispersal Kernels and Population Connectivity - A Modeling Perspective

Mobile marine species are able to navigate in their environment, making use of a range of cues to accomplish distinct tasks, such as to locate forage or breeding grounds. Movement to a stimulus, or taxis, can influence group migration, colonization of new areas, and ultimately, the organization of the population. Thus, the understanding of navigation is fundamental to understand population dynamics, demographics, and ecology. Taxis is not only performed by adults, but also by their young. Amounting evidence shows that both fish and invertebrate larvae have an active role in their dispersal in the ocean, and are sentient to environmental stimuli, such as olfactory, acoustic, visual, and magnetic, using cues to guide their movement. Despite the fundamental role that behavior, particularly taxis, can exert on the extent of larval dispersal, survivorship and successful recruitment, orientation behavior is not typically considered in stochastic Lagrangian models developed for the study of larval transport pathways. In this study, we present new orientation modules developed within the open-source Connectivity Modeling System (CMS), suited to represent realistic three-dimensional dispersal and navigation of the early life history stages of fish in the ocean. We further derive dispersal kernels and connectivity networks for larval fish species with distinct traits using a series of external cues for navigation and examine how their taxis may influence the population dynamics. The capacity of CMS in simulating with accuracy complex Lagrangian and biological processes, provides a benchmark for reassessing the biophysical mechanisms driving the structure of marine populations and the consequences of altered environmental cues on their resilience.