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Task 2: Observations of natural spawning substrates

This report explores the observations of natural spawning substrates as part of the INTERREG IVA project, focusing on UK sites such as Selsey and Torbay. Through detailed stratification of habitats, including biotope points and habitat maps, the project employs standardized diving methodologies using circular belt and line transects to collect egg data. Preliminary results indicate significant discrepancies between estimated and actual egg counts, alongside challenges such as a lack of habitat maps and variability in survey methods. Findings will support future conservation efforts.

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Task 2: Observations of natural spawning substrates

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  1. Task 2: Observations of natural spawning substrates INTERREG IVA Project Background photo by kind permission of Paul Naylor

  2. Task 2: UK Sites Selsey Torbay

  3. Task 2:Stratification of Habitats

  4. E.g. Habitat Maps (Torbay)

  5. E.g. Biotope Points (Torbay)

  6. Task 2: Site Stratification (Torbay)

  7. Task 2: Site Stratification (Torbay)

  8. Task 2: Site Stratification (Torbay)

  9. Task 2: May & July Site Selection

  10. Task 2: Site Stratification (Selsey)

  11. Task 2: Diving Methodology (UK) • Circular belt transect (4m Radius) • An area of 50m2 surveyed • 4 replicates completed on each dive

  12. Task 2: Diving Methodology (UK) • Line Transects (12.5m in length) • An area of 50m2 surveyed • 4 replicates completed during each dive

  13. Task 2: Results and Analysis * The collection of eggs for Task 4 were recorded and collected from two sites (468 eggs) indicates the large discrepancy that may exist between estimated sampling and actual figures (1577 eggs) –Solutions?

  14. Task 2: Results and Analysis

  15. 2.1 Diving observations- Problems encountered • A lack of habitat maps for both sides of the Channel • A non standardised methodology for conducting surveys on both sides of the Channel • Issues with UK Site 2 (Selsey) seagrass restricted to Chichester Harbour. • Problems with variable estimates of eggs • Problems of variability between surveyors • Problems with data analysis of results

  16. Intertidal Natural Substrate Observations

  17. Artificial Substrate Observations

  18. Artificial substrates

  19. Artificial Substrate Deployment

  20. Monitoring • Deployed on April 20th 2010 • Monitored: • 1st July 2010 by Volunteer divers • 10th August 2010 by HSE divers • Substrates are currently still deployed to allow for all eggs to hatch prior to retrieval

  21. Preliminary Results

  22. Preliminary Results • Multifactor ANOVA shows, the factors of Time (P= 0.001) and Substrate Type (P= 0.000) and the interaction between Time and Substrate Type (P=0.000) were significant for both the number of eggs and clutches laid on each array. • Significantly more eggs were laid April-June than June-August, and in the first time period significantly more eggs were laid on the pot structures than the other substrates. • However, the factor of Site (P=0.922) and its interactions were not significant in the number of eggs and clutches laid.

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