Agenda and draft minutes

RESOLVED that the minutes of the Crustacean Deaths Collaborative Working Group held on 13 October 2023 be confirmed and signed by the Chair as a true record.

None noted.

None recorded.

Dr G Caldwell, University of Newcastle

Professor D Roberts, University of Durham

Professor D Roberts, University of Durham, Department of Geography

Professor Roberts, who was welcomed to the Group by the Chair, advised that he was working as part of the community effort as a sedimentologist with expertise in how sediment is deposited in coastal environments. Professor Robert’s interest in the area had developed over decades, particularly in relation to waste produced as a result of coal mining activity and he has extensive experience of collecting cores from coastal areas.

Professor Roberts advised that, following the mortality event, scientists have been examining dredging activity to assess how sediment may have found it’s way to the sea floor, and what the sediment may contain. Cores had been retrieved as part of a collaborative process between the scientific and fishing communities and were currently in the process of being analysed for content. Within 6 – 12 months comprehensive results relating to the characteristics of the sediment should be available.

Professor Roberts guided the Group though a presentation, and the following observations and comments were noted:

·         Plumes of sediment were released during the dredging process that were not contained. Further to this, plume is a dynamic entity which moves up and down the river with the action of the tide. For this reason, several testing points were utilised.

·         Material that is dredged and goes into suspension in the water column will slowly settle and eventually reach the sea floor, providing a record of the sediment that has been released.

·         The law of superposition states that younger sediments lie above older sediments and the most recent sediment layers sit on top of the sediment pile. Sediment tells us about the depositional processes and pollutant signals.

·         The Group noted the location of Tees core samples and were advised that sediment cores were taken to the lab for analysis, with data derived from the following processes:

o   MSCL scans to ascertain the physical properties of the core.

o   CT scans, which allowed researchers to look inside the core to define what the sediment is.

o   XRF scans which provided elemental analysis.

·         Findings from core sample analysis showed the following:

S2a (pre-dredge sediment)

·         Dark brown; muddy sand; massive; macrofauna (worms, molluscs, gastropods); bioturbated.

·         High density.

·         High magnetic susceptibility.

·         Elemental signal: Zn/Fe/Al ?; Pb/Cu/Cr/V?

S3 (pre-dredge overlain by thin dredge)

Pre-dredge

·         Dark brown, muddy sand, macrofauna (worms, molluscs, gastropods)

      Dredge

·         A thin cap of red, muddy sand on top, lacking fauna, not bioturbated, laminated.

·         Drop in Mag Sus and density.

·         Drop in elemental signal (Zn, Cu, Pb, Fe)

S7 (pre-dredge overlain by thin dredge)

Pre-dredge

·         Dark brown, muddy sand, no macrofauna

Dredge

·         10cm cap of red, mud, lacking fauna; laminated

·         Drop in Mag Sus and density.

·         Drop in elemental signa (Zn, Cu, Pb, Fe, Al)

S4 (pre dredge overlain by thin dredge)

Pre-dredge

·         Dark brown, muddy sand, no macro fauna

Dredge

·         32cm cap of red, mud, lacking fauna; laminated

·         Drop in Mag Sus and density

·         Drop in elemental signal (Fe), spikes in Cu/Zn

S5a (pre dredge overlain by thin dredge)

Pre-dredge  ...  view the full minutes text for item 46.

Members were invited to start collating ideas in preparation for the concluding meeting being held in January.

A discussion took place regarding an extension of the work beyond February 2024. Owing to purdah and the fact that the Group had already worked beyond it’s time remit, it was agreed that the work should conclude in February.

A Member suggested that the focus of the report should be on looking forward as opposed to finding causes for the mortalities.

The following actions were agreed:

·         An invitation to December’s meeting be sent to Mayor Houchen, the Environment Agency, the Marine Management Organisation and Centre for Fisheries and Aquaculture Science.

·         Request the public presentation from Dr Caldwell.

·         Organise a trip to Whitby Lobster Hatchery for members of the Working Group.

·         Friday 1 December 2023 at 10am – TBA

·         Friday 12 January 2024 at 10am - TBA

Meetings scheduled as follows:

·         7 December 2023 (moved from 8 December)  - TBA

·         12 January 2024 - TBA