Embryonic development and metabolic costs in Gulf killifish Fundulus grandis exposed to varying environmental salinities

Abstract

The Gulf killifish (Fundulus grandis) is a euryhaline fish found in coastal marsh along the entire of Gulf of Mexico and southern Atlantic of coast of the United States. The objective of this study was to investigate the effects of salinity on embryogenesis in the Gulf killifish. Four recirculation systems at salinities of 0.4, 7, 15, and 30 g/L were maintained at a static temperature with flow-through trays, containing embryos (n = 39) placed in triplicate into each system. Throughout embryogenesis, the rate of development, ammonia and urea excretion, and heart rate were monitored. Percent hatch was recorded, and morphological parameters were measured for larvae at hatch. As salinity was increased, the rate of embryogenesis decreased. Salinity significantly affected percent hatch with an 80.0% ± 2.6% for 7 g/L and 39.1 ± 4.3, 45.4 ± 4.5, and 36.3% ± 12.0% for 0.4, 15, and 30 g/L, respectively. Salinity and stage of development significantly affected production of ammonia and urea. As salinity increased, the dominate metabolite end product changed from urea to ammonia. However, the 15 g/L salinity treatment had the two highest levels of urea recorded. Heart rate was unaffected by salinity but increased throughout embryogenesis and remained constant once embryos reached stages where hatching has been recorded. While mean total length was not affected by salinity, embryos incubated in 30 g/L produced larvae with significantly thicker body depth at hatch. The 0.4, 7, and 15 g/L salinity treatments all had similar mean hours to hatch. The 30 g/L treatment resulted in a significantly longer mean time to hatch and smaller body cavity area at hatch.

Combined effects of Deepwater Horizon crude oil and environmental stressors on Fundulus grandis embryos

“…High temperatures have also been shown to significantly decrease total length and body depth of laboratory‐hatched F . grandis embryos (Brown et al ). Dissolved oxygen levels, which fluctuate in estuaries inhabited by F .…”

Diet-Induced Fatty Acid Variation in Critical Tissues of a Spawning Estuarine Fish and Consequences for Larval Fitness

“…Gulf killifish Fundulus grandis is characterized by high levels of physiological plasticity (Griffith 1974;Martínez et al 2006;Brown et al 2012;Patterson et al 2012) and creates important ecological linkages in estuaries it inhabits (Subrahmanyam and Drake 1975). Established hypotheses regarding a dietary requirement for LC-PUFAs in fishes may not be applicable for F. grandis as this euryhaline species occupies a distinctive margin between freshwater and marine systems.…”

Egg Production of Gulf Killifish Is Dependent on Broodstock Rearing Density but Not Spawning Substrate Surface Area

“…During the acclimation period, salinity was increased to 8‰ and temperature was increased by 1°C per day to 25°C for increased egg fertilization (Brown et al. ). Tanks (3,600 L; 2.3‐m diameter) used in each experiment ran on separate RASs (a total volume of 4,000 L) containing a 120‐W ultraviolet sterilizer (Smart High Output Sterilizer; Pentair Aquatic Eco‐Systems, Apopka, Florida) and a bead filter (PolyGeyser Bead Filter; Aquaculture Systems Technologies, New Orleans, Louisiana).…”