DigiJel - Development of an in situ optical system for assessment of jellyfish populations in the open ocean

Jellyfish occur sporadically and in very high numbers causing large economic losses to fisheries and aquaculture. They can damage industrial plants (for example by clogging power station cooling systems), and injure recreational swimmers and impact tourism. It has been suggested that jellyfish will replace the fish-dominated food webs in a future warmer ocean with higher CO2 levels. Despite these potentially large socio-economic impacts and the likely trends over the coming decades, we know surprisingly little about the abundance and distribution of jellyfish. This is largely because sampling of gelatinous organisms is notoriously difficult owing to their fragile nature and, in addition, temporal and spatial variability is particularly high for this group of organisms.

A new generation of optical systems has the potential to transform the way in which the abundance and characteristics of this group of organisms can be assessed. There are several systems commercially available but none are suitable to quantify jellyfish abundance and characteristics over time, as typically the water volume sampled is too small. This PhD project aims to develop and test an in situ imaging device which enables to quantify jellyfish in the ocean.

The rapid advance of camera and computing technologies now allows the production of cheap and potentially disposable camera systems that could be installed at strategic monitoring sites. The student will review current available technologies and techniques, identify the best approach to imaging jellyfish, and build a prototype system targeted to jellyfish. We have recently developed a stereo camera system to allow imaging larger volumes of water and retrieve size information, which could be used as a starting point. The student will test a prototype in the lab and in a nearby lake, which has a year-round population of Moon jellyfish. The successful prototype will then be deployed at the open ocean long-term monitoring site, the PAP Observatory (Porcupine Abyssal Plain). Besides the engineering aspects, you will develop the image analysis so that automation of the data gathering can ultimately be achieved. The collected data can then be used to investigate jellyfish population dynamics.

The NEXUSS CDT provides state-of-the-art, highly experiential training in the application and development of cutting-edge Smart and Autonomous Observing Systems for the environmental sciences, alongside comprehensive personal and professional development. There will be extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial / government / policy partners. The student will be registered at the University of Southampton, and hosted at the National Oceanography Centre. Specific training will include:

- development and calibration of an underwater imaging system to provide data on the size, abundance and temporal variability of large jellyfish targets.

- ruggedization of prototype for application in aquatic settings including choice of suitable materials, health and safety aspects and user-friendliness

- familiarization with environmental monitoring techniques and the importance of spatial and temporal scales

- 3D image analysis techniques

- automatic image analysis

- statistics for analyzing environmental data