Researchers have found that not all marine prey animals are equal when it comes to nutritional value, despite being the same size.
The team from the University of California, San Diego studied a mass starvation event along the coast of California.
The study showed that prey can vary massively in terms of the nutritional value they provide to predators, even among animals of the same size and weight and from the same species. The team found that this variance can prompt predators to adjust their foraging behavior to accommodate it. The new study sheds light and improves our understanding of the complex food webs in our oceans.
Commenting on the study, co-author Stephanie Nehasil stated:
“We were surprised by how much variation there was within a single species. You could have two fish side-by-side that are the same size but have a huge range of variation in the amount of energy they provide. In some cases, predators would need to consume tens of thousands of the smaller, lower-quality fish to survive, and that’s just not possible.”
Discussing how their interest in the study was aroused, she added:
“We saw a lot of mortality, which led us to question whether prey abundance or availability had changed during the event. Looking more closely at shifts at the base of the food web, we began to wonder whether it wasn’t just the amount of food that had changed, but the quality as well. You have to use the currency of energy value to inform bioenergetics models. To help us predict what will happen as our climate and oceans change we need this baseline ecosystem data, especially to understand prey dynamics and how predators are going to respond.”
While fellow co-author Professor Carolyn Kurle, who is affiliated with the Southwest Fisheries Science Center (NOAA) and UC Santa Cruz, as well as being a faculty member in the Department of Ecology, Behavior, and Evolution, added:
“This is another piece of information to help inform our models to get a better understanding of how these ecosystems work, so we can recognize subtle dynamics that might otherwise be overlooked and respond more thoughtfully to environmental shifts. This information will help us understand the complexity of these ecosystems that so many care about, especially the fishers and others who use the ecosystem.”
Krule added:
“We all want to have healthy ecosystems and there are many stakeholders who want these systems to succeed. We want everyone to have the best data possible to make important analyses and estimations. Anytime we can provide a little more understanding of ecosystem complexity it’s valuable and important.”
