In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27th to April 11th, and May 10th through July 27th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) model framework was utilized in this study in conjunction with (1) combined-effects calculation schemes using catch per unit effort (CPUE) data and (2) hydrodynamic model (msbCOAWST) output to determine if there was a significant impact from the 2019 BCS diversions.
The geometric mean was determined to be the best combined-effects model for estimating habitat suitability model values when considering salinity, temperature, and depth in combination (SxTxD and SxT) The results for brown shrimp and blue crabs indicated that there was a consistent significant impact from BCS outflows in response to salinity across all age classes and all critical ecological periods, while impacts in response temperature were more variable, with significantly impacts on the younger age classes (larvae) and more developed blue crabs (juvenile and adult male). The significant impacts were primarily seen in Louisiana and Mississippi in response to salinity and temperature for both species, with few significant impacts seen in Alabama.
","abstract_html":"<p>In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27<sup>th</sup> to April 11<sup>th</sup>, and May 10<sup>th</sup> through July 27<sup>th</sup>) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (<em>Farfantepenaeus aztecus </em>and<em> Callinectes sapidus</em>) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) model framework was utilized in this study in conjunction with (1) combined-effects calculation schemes using catch per unit effort (CPUE) data and (2) hydrodynamic model (msbCOAWST) output to determine if there was a significant impact from the 2019 BCS diversions.</p> <p>The geometric mean was determined to be the best combined-effects model for estimating habitat suitability model values when considering salinity, temperature, and depth in combination (<em>SxTxD </em>and <em>SxT</em>) The results for brown shrimp and blue crabs indicated that there was a consistent significant impact from BCS outflows in response to salinity across all age classes and all critical ecological periods, while impacts in response temperature were more variable, with significantly impacts on the younger age classes (larvae) and more developed blue crabs (juvenile and adult male). The significant impacts were primarily seen in Louisiana and Mississippi in response to salinity and temperature for both species, with few significant impacts seen in Alabama.</p>","abstract_has_math":false,"creators":["Dyson, Mallory"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Dr. Scott Milroy","Dr. Kim de Mutsert","Dr. Jerry Wiggert"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12-01T08:00:00Z","date_published":"2025-12-01T08:00:00Z","updated_at":"2026-07-24T05:45:55Z","subjects":["Bonnet Carré Spillway","brown shrimp","blue crab","habitat suitability","msbCOAWST","Marine Biology","Oceanography"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/1158","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Scott Milroy","Dr. Kim de Mutsert","Dr. Jerry Wiggert"]},{"key":"dc:creator","label":"Author","values":["Dyson, Mallory"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2025-10-24T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Bonnet Carré Spillway","brown shrimp","blue crab","habitat suitability","msbCOAWST","Marine Biology","Oceanography"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://aquila.usm.edu/masters_theses/1158"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27th to April 11th, and May 10th through July 27th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) model framework was utilized in this study in conjunction with (1) combined-effects calculation schemes using catch per unit effort (CPUE) data and (2) hydrodynamic model (msbCOAWST) output to determine if there was a significant impact from the 2019 BCS diversions.
The geometric mean was determined to be the best combined-effects model for estimating habitat suitability model values when considering salinity, temperature, and depth in combination (SxTxD and SxT) The results for brown shrimp and blue crabs indicated that there was a consistent significant impact from BCS outflows in response to salinity across all age classes and all critical ecological periods, while impacts in response temperature were more variable, with significantly impacts on the younger age classes (larvae) and more developed blue crabs (juvenile and adult male). The significant impacts were primarily seen in Louisiana and Mississippi in response to salinity and temperature for both species, with few significant impacts seen in Alabama.
"]},{"key":"dc:title","label":"Title","values":["Isolation of the 2019 Bonnet Carré Spillway Effects on the Habitat Suitability of Brown Shrimp (Farfantepenaeus aztecus) and Blue Crab (Callinectes sapidus) Using a Modeling Approach"]}]}],"canonical_facts":{"dc:contributor":["Dr. Scott Milroy","Dr. Kim de Mutsert","Dr. Jerry Wiggert"],"dc:creator":["Dyson, Mallory"],"dc:date.available":["2025-10-24T07:00:00Z"],"dc:description.abstract":["In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27th to April 11th, and May 10th through July 27th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) model framework was utilized in this study in conjunction with (1) combined-effects calculation schemes using catch per unit effort (CPUE) data and (2) hydrodynamic model (msbCOAWST) output to determine if there was a significant impact from the 2019 BCS diversions.
The geometric mean was determined to be the best combined-effects model for estimating habitat suitability model values when considering salinity, temperature, and depth in combination (SxTxD and SxT) The results for brown shrimp and blue crabs indicated that there was a consistent significant impact from BCS outflows in response to salinity across all age classes and all critical ecological periods, while impacts in response temperature were more variable, with significantly impacts on the younger age classes (larvae) and more developed blue crabs (juvenile and adult male). The significant impacts were primarily seen in Louisiana and Mississippi in response to salinity and temperature for both species, with few significant impacts seen in Alabama.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/1158"],"dc:subject":["Bonnet Carré Spillway","brown shrimp","blue crab","habitat suitability","msbCOAWST","Marine Biology","Oceanography"],"dc:title":["Isolation of the 2019 Bonnet Carré Spillway Effects on the Habitat Suitability of Brown Shrimp (Farfantepenaeus aztecus) and Blue Crab (Callinectes sapidus) Using a Modeling Approach"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:45:55Z"}