Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

ENVIRONMENTAL HYPOXIA IN ECOLOGICALLY IMPORTANT ESTUARIES AND ITS EFFECTS ON NATIVE FISH SPECIES DURING EARLY DEVELOPMENT

Magaleate Kostelnik*, Bing Ouyang, Paul S. Wills, and Sahar Mejri

 

Harbor Branch Oceanographic Institute , Florida Atlantic University (HBOI-FAU)

5600 US 1 North , Fort Pierce, FL 34946

 Email: mkostelnik2022@fau.edu

 



Estuaries like th ose in the Gulf of Mexico and the Indian River Lagoon (IRL)  host some of the  most species-diverse ecosystems in North America. However, the distribution and intensity of hypoxia (low dissolved oxygen, DO) is increasing due  to  eutrophication, ‘dead zones’,  and algal blooms. Effects of coastal hypoxia is well-studied in adult fish, yet gaps of information remain in terms of fish  early life stages,  including potential consequences to early  development, hatching success, and ultimately recruitment of economically important native species, including the  Florida Pompano (Trachinotus carolinus) and Red Drum (Sciaenops ocellatus) . To test the effects of hypoxia ,  fertilized eggs were incubated in two treatments  of severe and moderate hypoxia (20 and 50% DO saturation , 1.4 mg/L and 3.3 mg/L, respectively )  and one treatment of normoxia (100% DO saturation, 7 mg/L) in a recirculating aquaculture system (Fig.1) .  Treatments  were  run in triplicates (n=3).  Eggs and larvae were sampled at 24- and 48-hours post-fertilization to assess  embryonic and larval development, survival, and fatty acid lipids use .  Lipids were extracted from each sample and separated into neutral (used for energetic purposes) and polar (used for membranous development) fatty acids. The concentration of these fatty acids informs us of the potential effects of severe hypoxia on energy demand and membrane  permeability (i.e., homeostatis mechanism) .  Changes in hatch success, survival, and overall development will be presented . This project enhances the understanding of marine ecosystem function  where hypoxic zones are prevalent  in areas like in the IRL, and the Gulf of Mexico. Investigating the potential impacts of hypoxia on early larval stages improves conservation and management strategies for recruitment of these species.