Intraspecific diversity in Atlantic cod drives divergent trophic cascades across a coastal food web

Intraspecific diversity can profoundly shape ecological interactions, yet its role within complex food webs remains challenging to quantify. We explored how eco-evolutionary divergence within Atlantic cod (Gadus morhua), specifically between the resident Fjord and migratory North Sea ecotypes, influences food web structure and function in a coastal marine ecosystem. Using key trait differences, including growth rate, age, and size at maturation, reproductive investment, and ontogenetic dietary shifts, we parameterized an allometric trophic network (ATN) model with empirical data from the Norwegian Skagerrak. The high-resolution network comprised 148 trophic guilds and 2054 feeding links, permitting resolution of ecotype-specific interactions. We found pronounced intraspecific divergence: North Sea cod reached higher trophic position earlier, exerting greater interspecific influence, whereas Fjord cod retained higher early-stage biomass, intensifying intraspecific competition between eco..., , , # **Intraspecific diversity in Atlantic cod drives divergent trophic cascades across a coastal food web**

[https://doi.org/10.5061/dryad.tqjq2bw6c](https://doi.org/10.5061/dryad.tqjq2bw6c)

## Description

This repository contains data files and code used to simulate, analyze, and visualize coastal marine food webs, examining the effects of Atlantic cod (*Gadus morhua*) ecotype diversity on trophic cascades. Food web dynamics were simulated using Matlab and analyzed and visualized in R.

## Simulation Data and Code

### Matlab Simulation Files

Matlab data files hosted on Zenodo include four parameterized food web matrices representing alternative Atlantic cod ecotype scenarios in the Skagerrak coastal system:

* **5_Skagerrak_2BothEcotypes.mat** – Food web including both Fjord and North Sea cod ecotypes
* **5_Skagerrak_2FCod.mat** – Food web including Fjord cod ecotype only
* **5_Skagerrak_2NSCod.mat** – Food web including North Sea cod ecotype only
* **5_Skagerrak_2NoEcotypes.mat** –...,