Location: Aquatic Animal Health Research
Project Number: 6010-32000-027-020-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2025
Objective:
Entering aquatic ecosystems via agricultural runoff, herbicides can potentially have adverse effects on a variety of taxa. However, the majority of previous studies have focused on singular effects of herbicides on animal biology or behavior. We propose an integrative study, monitoring the effects of herbicide exposure on genomic, pathophysiological, and behavioral levels in Channel Catfish (Ictalurus punctatus).
Approach:
1. After exposing mature Channel Catfish to ecologically relevant levels of commonly used herbicides, we plan to conduct transcriptomic analyses on tissues such as the brain, liver, gonad, and immune tissue samples to characterize transcriptional responses to herbicide exposure. We will also examine the extent to which herbicide exposure can influence susceptibility of catfish to industry relevant bacterial pathogens through well-established challenge models.
2. Next, we will examine the behavioral consequences of herbicide exposure on reproductive, anti-predator, and social behavior. After spawning, male Channel Catfish guard the nest and fry following hatching. Literature in other territorial fishes document declines in territorial and guarding behaviors after herbicide exposure but little is known regarding Catfish. We will record and score herbicide-exposed male guarding behaviors (nest fanning, mouthing, and defense) when faced with a potential predator attack. We will also monitor reproductive hormones in males and females exposed to herbicide during the spawning season to determine if female pheromone release and male 11-ketotestosterone production is impacted.
3. Finally, after exposing fish to herbicide(s), we will also measure the auditory sensitivity for each fish using the Auditory Brainstem Response (ABR). This objective is also highly relevant to Ictalurid catfish as they are considered hearing specialists and have more sensitive hearing relative to other fishes.
