Modeling Fish Movement in 3-D in the Gulf of Mexico Hypoxic Zone
Authored by Elizabeth LaBone, Dubravko Justic, Kenneth Rose, Lixia Wang, Haosheng Huang
Date Published: 2019
DOI: 10.1007/s12237-019-00601-6
Sponsors:
United States National Science Foundation (NSF)
Platforms:
FVCOM
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
The hypoxic zone on the Louisiana-Texas shelf varies in its area,
volume, and vertical distribution. Vertical movement to avoid hypoxia
(dissolved oxygen (DO) concentration <2 mg/L) can be important to
understanding fish exposure to low DO. Fish movement was simulated in
2-D (bottom layer) and 3-D with movement algorithms that depended on DO
fields generated by a 3-D coupled hydrodynamic-water quality model. Fish
exposure to low DO was simulated using two alternative movement
algorithm groups, good and bad avoidance competency, and three
perception ranges for detecting DO. The algorithm groups (default and
avoidance) differed in whether the default movement included a downward
bias. Avoidance competencies differed in the degree of random variation
imposed on the avoidance movement. Fish exposures to low DO were
simulated in 2-D and 3-D for July 24 to August 2 of 2002 during which
hypoxia showed both horizontal and vertical variations. The addition of
vertical movement (3-D) resulted in mean cumulative hypoxia exposures
(days with DO<2 mg/L) typically about 8 times lower than the 2-D
movement results (e.g., similar to 0.1 days versus 0.8 days with good
avoidance), but vertical avoidance did not decrease the cumulative days
of exposure of fish to moderate hypoxia (2-4 mg/L). The differences
between the 2-D and 3-D model results, coupled with the limited data on
vertical fish movement in response to hypoxia, suggest that 3-D movement
could affect exposure to hypoxia and should be considered for spatially
complex habitats.
Tags
Individual-based model
behavior
modeling
Habitat fragmentation
Animal movement
Hypoxia
Consequences
Water-quality
Random-walk
Atlantic croaker
Croaker
Gulf of mexico
Brown shrimp
Vertical movement
Lagrangian-agent method