Workpackage 5 aims to examine the factors affecting scavengers feeding on jelly-falls. This is important as previous work has shown that scavengers play a major role in utilizing and removing jelly-falls in the benthic fjord environment. We will focus on two research questions:
1. Are scavengers deterred from consuming very large jellyfalls due to a high concentration of noxious sulphides and ammonium released by decaying jelly-falls?
2. What is the impact of organic food supply on the scavenging of jelly-falls?
Findings will determine under which conditions the removal of jelly-falls by scavengers are maximized. Understanding this in relation to fish farms stresses will be particularly valuable to manage the placement of fish farms to help minimize jelly-fall impacts.
The scavenger studies will be conducted using a deep sea lander equipped with a Nikon D7100 SLR contained in a deep sea underwater housing viewing a jelly-fall bait. The camera will take time lapse images of scavengers feeding on the bait.
The scavenger camera lander was assembled at IRIS to determine the appropriate camera settings and also the image field of view within which the jelly-fall bait will be placed. Some lander deployments will use a large mass of jellies (10 – 20 kg) to simulate an extensive jelly-fall event.