QUADRAT DTP CASE: Acoustic detection & characterisation of cod in the north east Atlantic

After decades of overexploitation in the 20th century, most fish stocks in the North east Atlantic are now sustainably fished and showing strong signs of recovery (Fernandes and Cook, 2013). However, there are still some stocks which have been slow to recover and others which are subject to new problems such as discarding (Fernandes et al., 2011). Certain cod stocks, in particular, are prone to these ongoing problems: these include the cod stocks in the Irish Sea, North sea and west of Scotland. This project aims to use intelligence and data gathered from fishermen to understand how cod hotspots can be detected using acoustic methods. This will enable acoustic surveys for cod, to determine sustainable exploitation regimes, as well as mitigating for discarding. Both of these elements contribute to the Sustainable development Goal of “Life below water” which aims to ”Conserve and sustainably use the oceans, seas and marine resources for sustainable development”, specifically targets 14.4 Sustainable Fishing) and 14.A (Increase Scientific Knowledge, Research and Technology for Ocean Health).

Acoustics are used extensively to detect pelagic (midwater) fish, but have hitherto been difficult to use for demersal species such as cod. However, as they recover, the ability to detect demersal fish with acoustic devices will improve as they school in larger numbers. This has been shown to occur in the great Canadian Northern cod stock, where (Rose and Rowe, 2015) used acoustic devices to quantify massive schooling behaviour of cod and estimate the population size to have recovered to levels not seen since the collapse in 1992.

Fishermen in Northern Ireland are now reporting similar schooling behaviour, which they attribute to cod.

The project has three principal objectives, which would form putative thesis chapters:

1) Characterise cod hotspot echograms from the Irish Sea. This will be achieved by collecting paired datasets of echograms from the cod hotspot, determined by fishermen as being cod, and associated biological ground truth data, from trawl catches from the hotspot. Echograms are high resolution two dimensional (2D) representations of scattering in the water column, effectively, 2D quantitative images.

2) Develop an algorithm to detect cod hotspots from echosounder data. This will be achieved by applying signal processing techniques from at least two different echosounder frequencies along with image analysis techniques. User friendly software (Sonardata Echoview) will facilitate this development.

3)Compare cod echograms in the Irish Sea with those from other areas, namely the west of Scotland and the North Sea. A Scottish fisherman with similar interests and claims, has agreed to provide additional data.

4)Investigate echograms from other species to determine if these too can be characterised. Other species such as haddock and whiting will also be caught and these catches will be associated with echograms to determine if they can be characterised too.

The studentship provides a student with an excellent interdisciplinary opportunity to combine physics, engineering and biology, to learn about fisheries acoustics. This is a globally recognised state of the art technique to study the abundance, distribution and behaviour of fish and other marine resources.

This project is supported by AFBI as a CASE partner.

ELIGIBILITY

Candidates should have (or expect to achieve) a minimum of a 2.1 Honours degree in a relevant subject. Applicants with a minimum of a 2.2 Honours degree may be considered providing they have a Distinction at Master’s level.

APPLICATION PROCEDURE:

• Apply for Degree of Doctor of Philosophy in Biological Science
• State name of the lead supervisor as ‘Name of Proposed Supervisor’ on application
• State ‘QUADRAT DTP’ as Intended Source of Funding
• Select the ‘Visit Website’ to apply now