Incorporating the Impacts of Climate Variability on Growth in Fish Population Dynamics Models

• Main Author: Moron Correa, Giancarlo Helar
• Other Authors: Ciannelli, Lorenzo, Hurst, Thomas, Stockhausen, William, Kristiansen, Trond, Pilcher, Darren, Kotwicki, Stan, Barnett, Lewis, Fuentes, Claudio, McGilliard, Carey, College of Earth, Ocean, and Atmospheric Sciences
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Fish populations; Bering Sea
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/t148fq64j

Variations in ocean conditions influenced by climate fluctuations may impact fish populations by changing their spatial distribution, physiology, survival, and other ecological features. Somatic growth is a crucial aspect of the biology of fishes and an important contributor to biomass fluctuations. Climate variability also affects somatic growth rates along the fish life span, impacting the fish ecology and the fishery. In this dissertation, I present multiple analyses on how fish somatic growth variability may be incorporated in population dynamics models, a quantitative approach to studying climate's impacts on fish populations. Chapter 1 introduces fish somatic growth variability, population dynamics models and their importance, current strategies to incorporate growth in population dynamics models, and an introduction to the ecology of the Pacific cod in the eastern Bering Sea, fish stock used as a case study in this dissertation. Chapter 2 investigated how projected climate under two emission scenarios (RCP4.5 and RCP8.5) might impact the growth and survival of Pacific cod’s early life stages in the eastern Bering Sea. Specifically, I evaluated the impacts on the following biological variables: (1) hatch success, (2) survival probability, (3) growth, and (4) spatial distribution. I implemented a mechanistic individual-based cod larvae model that quantifies changes and the larval behavioral response to the physical and biological environment. The results indicate that, under the RCP8.5 scenario, the temperature in the larvae habitat will increase by ~ 2 C while pCO2 will triple by 2100 compared to present-day values. These changes will increase hatch success and standard length (mm); however, survival probability will decrease by ~85% and recruitment by 50%. A shallow retention area was detected in the southeast part of the eastern Bering Sea, being this area also the most vulnerable to the future climate. Chapter 3 explored how somatic growth variability impacts the age composition estimation, a critical ...