American Shad after Spawning (image) North Carolina State University Share Print E-Mail Caption American shad swim upstream in freshwater rivers to spawn. The fish don't feed while spawning, leading to significant weight loss (as seen here). Anything that delays their spawning journey can cause shad to lose so much weight that they die. Credit Joshua Raabe Usage Restrictions Photo credit must be given. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.