Abstract:

This dataset reports fish weight, liver weight, hepatosomatic index (HSI), and pituitary weight of Gulf toadfish exposed to different Polycyclic aromatic hydrocarbons (PAHs) concentrations. The objectives of the experiments are to assess the impacts of Deepwater Horizon (DWH) oil on the vertebrate stress response and the trajectory for recovery. Our research integrates molecular, cellular, gland/organ and whole animal physiological and behavioral studies using a benthic marine teleost, the Gulf toadfish, a resident of the Gulf of Mexico. These studies evaluates multiple pathways (e.g., pituitary fatigue, reduced receptor sensitivity, disruption or overstimulation of cortisol biosynthesis) and the consequence of these changes at the whole animal level (e.g., changes in carbohydrate metabolism, immune capacity, and responses to natural stresses such as predation and social interaction). In this series of experiments, the fish weight, liver weight, and pituitary weight are evaluated during short-term exposures to DWH oil. Each exposure is followed by a complementary recovery period (i.e., no oil or PAH exposure) to assess the recovery trajectory. Experiments are done at RSMAS, University of Miami, MTLSS Building Rm. 211, during 2018.

Suggested Citation:

McDonald, M.D.; Alloy, M.M.; Cartolano, M.C.. 2018. Experiments to evaluate the impacts of acute exposure of PAHs on Gulf toadfish. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-7yxx-3448

Purpose:

Determine whether acute exposure to environmentally realistic concentrations of PAHs would have an impact on fish weight, liver weight or hepatosomatic index, which could be signs of metabolic disturbance; or pituitary weight, which could be a sign of stress axis hyperactivity.

Data Parameters and Units:

Replicate fish id (AXXX-B-C-DZ where A = treatment; X = initial sample; C = control; L = low concentration exposure; M = medium concentration exposure; H = high concentration exposure), XXX=fish id, B=trial number, C=fish state (not stressed [NS] or stressed [S]), D=time sample taken in hours (h) or days (d), z= period sample taken (either during exposure [E] or during recovery [R]), fish mass (g), liver mass (g), hepatosomatic index (HSI), empty tube (g), pituitary and tube (g), pituitary mass (g). Cells that are crossed out indicate the fish died during the experiment, “nd” means data point not determined, and data in color red means aberration in pituitary weight data (e.g., pituitary + tube weight is less than tube weight alone; pituitary weight is exceedingly high).

Methods:

Gulf toadfish were exposed to different PAH concentrations. The exact age is not known but based on their size they were likely > 2 years old. They were collected in Biscayne Bay along the Miami coastline. The fish were acclimated to the laboratory environment for at least 1 month during which time they were treated for parasites. The fish were not acclimated to the tanks associated with the exposure system since the system had to be primed with oil and we wanted to catch an acute response to the oil. So, the fish were gently moved from their acclimation tanks to the exposure system at t = 0. There were 8 tanks per concentration (control/zero, low, medium, and high PAH exposure) and 10 fish in each tank. “No stress fish” were taken out of the exposure system (one fish was taken out of four different tanks making a total of N=4 "no stress fish" removed from the exposure system per time point per concentration) and sampled immediately. “Stressed fish” were exposed to a simulated predation stress before sampling. Briefly, at each concentration and time-point, one fish was taken out of four different tanks making a total of N = 4 fish removed from the exposure system and placed into a stainless-steel bowl filled with aerated seawater. The bowl was placed at the bottom of a Cuisinart stand mixer and the head of the mixer (with the dough hook accessory attached) was lowered into the water. The stand mixer was turned on at the lowest setting for 30 secs, which prompted the fish to avoid the dough hook as they would a predator. After 30 secs, the head of the stand mixer was raised so that the dough hook was elevated (and the fish no longer had to actively avoid it) but it was kept in the upper 1/3 of the water column for 15 minutes. After 15 minutes, fish were sampled from the water every 5 minutes until all the fish were sampled. The fish were exposed to oil for up to 7 days. Samples were taken at 4h, 8h, 24 h, 3 days and 7 days during the exposure. The fish were recovered for up to 7 days. Samples were taken at 4h, 8h, 24 h, 3 days and 7 days post recovery. We did two separate trials to be able to get N = 8 fish per concentration per time point and per stress level. N = 4 fish were completed for each concentration, time point and stress level for each trial. The average sum total PAH concentration was approximately 2 micrograms/L for the high dose and decreased by an order of magnitude for each dose.

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