Stock mapping, size structure and biological parameters of the clam Polititapes aureus in the shellfish production area of the southern Tunisian waters (Central Mediterranean)
and | Jun 05, 2021
About this article
Article Category: Original research paper
Published Online: Jun 05, 2021
Page range: 128 - 136
Received: Oct 27, 2020
Accepted: Nov 17, 2020
DOI: https://doi.org/10.2478/oandhs-2021-0012
Keywords
© 2021 Abdelkarim Derbali et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Surface area, the number of transects and replicates and stock levels (means ± SE) of Polititapes aureus in the shellfish production area of Sfax (south Tunisia)
| Sites | Surface (ha) | % of total surface | Number of transects | Number of replicates | Mean density (ind. m−2) ± SE | Mean biomass (g m−2) ± SE |
|---|---|---|---|---|---|---|
| Site 1 | 505 | 12.08 | 18 | 130 | 0.92 ± 0.3 | 2.74 ± 1.0 |
| Site 2 | 265 | 6.34 | 11 | 62 | 1.68 ± 0.7 | 6.12 ± 2.9 |
| Site 3 | 146 | 3.49 | 12 | 50 | 0 | 0 |
| Site 4 | 379 | 9.06 | 16 | 82 | 1.32 ± 0.4 | 5.38 ± 1.5 |
| Site 5 | 535 | 12.79 | 24 | 168 | 0.90 ± 0.2 | 1.34 ± 0.3 |
| Site 6 | 310 | 7.41 | 9 | 62 | 1.61 ± 0.4 | 3.08 ± 0.9 |
| Site 7 | 960 | 22.95 | 11 | 72 | 3.83 ± 1.8 | 6.28 ± 1.9 |
| Site 8 | 600 | 14.35 | 6 | 42 | 1.24 ± 0.5 | 4.07 ± 1.7 |
| Site 9 | 87 | 2.08 | 8 | 72 | 1.0 ± 0.4 | 2.80 ± 1.0 |
| Site 10 | 395 | 9.45 | 28 | 226 | 5.65 ± 1.3 | 11.88 ± 3.1 |
| Total | 4182 | 100 | 143 | 966 | 2.34 ± 0.4 | 5.28 ± 0.8 |
Sediment type and organic matter content recorded in the shellfish production area of Sfax (south Tunisia)
| Sites | % Gravel | % Coarse | % Medium sand | % Fine sand | % Silt/clay | Organic matter content (%) |
|---|---|---|---|---|---|---|
| Site 1 | 0 | 5.68 | 22.31 | 62.08 | 9.93 | 14.02 |
| Site 2 | 0.03 | 3.62 | 25.82 | 63.12 | 7.41 | 11.03 |
| Site 3 | 0.42 | 4.72 | 26.06 | 68.02 | 0.78 | 19.27 |
| Site 4 | 0.11 | 7.52 | 27.63 | 61.17 | 3.57 | 18.11 |
| Site 5 | 1.11 | 11.53 | 26.02 | 50.05 | 11.29 | 16.01 |
| Site 6 | 4.71 | 12.97 | 24.19 | 38.72 | 19.41 | 8.54 |
| Site 7 | 2.42 | 9.82 | 28.02 | 46.48 | 13.26 | 19.01 |
| Site 8 | 4.82 | 10.93 | 28.30 | 41.81 | 14.14 | 6.72 |
| Site 9 | 0.10 | 1.52 | 19.12 | 79.18 | 0.08 | 22.13 |
| Site 10 | 0.09 | 2.54 | 38.15 | 57.19 | 2.03 | 17.14 |
Polititapes aureus. Variability of minimum (Min.), maximum (Max), average (Mean), standard error (SE) and mode values of shell length (SL) in the shellfish production area of Sfax (south Tunisia), N (number of harvested specimens)
| Sites | N | Min. SL (mm) | Max SL (mm) | Mean SL (mm) | SE | Mode |
|---|---|---|---|---|---|---|
| Site 1 | 30 | 8.30 | 29.15 | 23.82 | 0.86 | 27.00 |
| Site 2 | 26 | 21.30 | 29.80 | 26.10 | 0.43 | 27.00 |
| Site 3 | 0 | 0 | 0 | 0 | 0 | 0 |
| Site 4 | 27 | 6.70 | 32.65 | 25.06 | 1.11 | 25.00 |
| Site 5 | 38 | 6.70 | 27.10 | 18.41 | 1.14 | 10.00 |
| Site 6 | 25 | 9.50 | 30.70 | 20.43 | 1.21 | 19.00 |
| Site 7 | 69 | 8.15 | 30.25 | 19.16 | 0.79 | 24.00 |
| Site 8 | 13 | 14.00 | 30.50 | 25.95 | 1.15 | 26.00 |
| Site 9 | 18 | 17.50 | 29.45 | 23.85 | 0.93 | 27.00 |
| Site 10 | 319 | 4.90 | 35.34 | 22.34 | 0.26 | 23.00 |