Biodiversity Data Journal :
Research Article
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Corresponding author: Ghollame Ellah Yacine Khames (khamesyacine@gmail.com)
Academic editor: Dimitris Poursanidis
Received: 10 Feb 2023 | Accepted: 22 Apr 2023 | Published: 16 May 2023
© 2023 Ghollame Ellah Yacine Khames, Aldjia Kherchouche, Zakia Alioua, Aziz Hafferssas
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Khames GEY, Kherchouche A, Alioua Z, Hafferssas A (2023) Temporal patterns of gelatinous zooplankton distribution and environmental drivers in the south-western Mediterranean Sea. Biodiversity Data Journal 11: e101790. https://doi.org/10.3897/BDJ.11.e101790
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This study aims to investigate the distribution of gelatinous zooplankton in relation to environmental parameters along the coastal regions of Algeria in the south-western Mediterranean Sea. A total of 48 species were recorded from nine sampling stations located in the central (Sidi Fredj) and western (Habibas Islands) sectors of the Algerian coast. The results showed that the seasonal distribution of gelatinous species exhibits significant variations. Amongst cnidarians, P. noctiluca, M. atlantica and A. tetragona are the most abundant species. Chaetognaths are primarily represented by F. enflata and P. friderici. Tunicates display high diversity, with T. democratica, O. longicauda and D. nationalis as the most abundant species. Lastly, in molluscs, H. inflatus and L. trochiformis are the most abundant species. The nMDS and ANOSIM analysis reveal significant differences in the ecological community structures between the Habibas Islands and Sidi Fredj. Redundancy analysis results show relationships between different marine species and environmental variables, such as temperature, chlorophyll a and salinity. The studied species exhibit positive or negative correlations with these variables, suggesting an influence of these factors on their abundance and distribution. This study enhances our understanding of the factors that govern the distribution and dispersal of gelatinous zooplankton in the Mediterranean Sea and has significant implications for predicting changes in the distribution of these species under future environmental scenarios.
coastal Algeria, pelagic ecology, gelatinous species, environmental parameters, distribution and dispersal, Mediterranean Sea
Gelatinous zooplankton, including Ctenophora, hydromedusae, scyphomedusae, Siphonophora, Chaetognatha Appendicularia, Doliolida and Salpida, are amongst the most abundant planktonic organisms in marine food webs (
Understanding how gelatinous zooplankton communities are influenced by environmental factors, such as local hydrography and physical forcing, can have important implications for fisheries and higher trophic predators (
Research on gelatinous zooplankton in Algerian waters is limited and incomplete, with a primary focus on copepods (
This study aims to address these gaps in knowledge by characterising the gelatinous zooplankton communities in two regions of the central and western sectors of Algeria, including the Habibas Islands, an important marine protected area and Sidi Fredj, a highly valued coastal zone. Two regions of the central and western sectors of Algeria were chosen for this investigation. In the west, the Habibas Islands are an important biological hotspot of marine and terrestrial biodiversity, classified as Specially Protected Areas under the Barcelona Convention framework (
In the western sector of the Algerian coast, the Habibas Islands (HI) are located 26 miles (41.8 km) from Cape Figalo west of Oran, 10 miles (16.1 km) from the port of Bouzedjar and 5.8 miles (9.3 km) from the nearest continental point at Madagh II. Sidi Fredj (SF) is located at the central sector of Algeria. It is exposed to strong demographic expansions and the coastal development of tourism activity and recreational ports (Fig.
The study involved collecting a total of 24 biological samples from two locations: Sidi Fredj and Habibas Islands. At Sidi Fredj, three samples were taken from each of the three stations during autumn, winter, spring and summer, resulting in a total of 12 samples. At Habibas, six samples were collected from each of the six stations during spring and summer, resulting in another 12 samples (Table
Areas |
Stations |
Longitudes |
Latitudes |
Season |
Sampling dates |
Habibas Islands |
HI1 |
1°10'W |
35°37'42'' |
Spring |
13/05/2012 |
Summer |
12/07/2012 |
||||
HI2 |
35°40'00" |
Spring |
13/05/2012 |
||
Summer |
12/07/2012 |
||||
HI3 |
35°41'00'' |
Spring |
13/05/2012 |
||
Summer |
12/07/2012 |
||||
HI4 |
1°8'W |
35°44'30" |
Spring |
13/05/2012 |
|
Summer |
12/07/2012 |
||||
HI5 |
35°44'48'' |
Spring |
13/05/2012 |
||
Summer |
12/07/2012 |
||||
HI6 |
35°45'24'' |
Spring |
13/05/2012 |
||
Summer |
12/07/2012 |
||||
Sidi Fredj |
SF1 |
2°50'E |
36°47'24'' |
Autumn |
18/11/2012 |
Winter |
04/03/2013 |
||||
Spring |
16/04/2013 |
||||
Summer |
11/07/2013 |
||||
SF2 |
36°48'12'' |
Autumn |
18/11/2012 |
||
Winter |
04/03/2013 |
||||
Spring |
16/04/2013 |
||||
Summer |
11/07/2013 |
||||
SF3 |
36°49'10'' |
Autumn |
18/11/2012 |
||
Winter |
04/03/2013 |
||||
Spring |
16/04/2013 |
||||
Summer |
11/07/2013 |
Under a Zeiss Stemi SV 6 (Germany) microscope, specimens were carefully examined and identified, based on appropriate taxonomic literature, including works by
Environmental parameters, including temperature, salinity and chlorophyll a, were mesured at a depth of 0 to 50 metres during zooplankton collections using a Niskin bottle. Temperature and salinity were measured at each sample using a multiparameter instrument (HI 9828-12202/Romania) at four depths (5, 15, 30 and 50 metres). However, we conducted the chlorophyll a assay in the laboratory using the Lorenzen technique (
The statistical analysis of the collected data was performed using R version 4.1.3 (
The first step was to apply the non-metric Multidimensional Scaling ordination (nMDS) to show the distribution of gelatinous zooplankton samples on the Algerian coast in both regions. This was followed by a non-parametric analysis of similarities (ANOSIM) on species abundance to test whether there was a significant difference between the studied regions (Sidi Fredj and Habibas Islands) and the sampling periods (months, seasons) (
To determine how the zooplankton community has changed over time relative to environmental variables, multivariate methods were used (
In May, the sea surface temperatures around the Habibas Islands were observed to fluctuate between 15.2°C and 19.9°C, while in July, they ranged from 17.1°C to 24.5°C. As for Sidi Fredj, the sea surface temperatures were relatively low during March (ranging from 15.3°C to 16°C) and April (ranging from 15.5°C to 16.4°C) and comparatively high in July (ranging from 17.9°C to 22.8°C) and November (ranging from 15.2°C to 18.5°C).
Regarding the sea surface salinity, values in the Habibas Islands ranged between 34 psu and 34.9 psu in May, while in July, they varied from 34.7 psu to 35.2 psu. In Sidi Fredj, the surface salinity was measured to be between 35.9 psu and 36.4 psu in March and between 35.8 psu and 36.1 psu in April, with a range of 35.7 psu to 36.5 psu in November. The maximum salinity was recorded in July, ranging from 36 psu to 36.7 psu.
Chlorophyll a recorded a maximum value at the Habibas Islands in May (ranging between 0.17 mg.m-3 and 0.37 mg.m-3). However, values were low in July (ranging between 0.008 mg.m-3 and 0.22 mg.m-3). At Sidi Fredj, chlorophyll a was highest in March (ranging between 0.22 mg.m-3 and 0.32 mg.m-3) and April (ranging between 0.01 mg.m-3 and 0.25 mg.m-3), followed by November (ranging between 0.11 mg.m-3 and 0.14 mg.m-3). The minimum chlorophyll a was registered in July with lower values (fluctuating between 0.01 mg.m-3 and 0.15 mg.m-3) (Fig.
The Habibas Islands and Sidi Fredj were found to harbour a total of 48 species of gelatinous zooplankton, belonging to five Chetognatha, six Mollusca, 13 Tunicata and 24 Cnidaria taxa (Table
Gelatinous zooplankton mean abundance (Abd) ind.m−3 and standard deviation (± SD) in Habibas Islands (HI) and Sidi Fredj (SF)
Taxa |
Habibas Islands |
Sidi Fredj |
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May |
July |
November |
March |
April |
July |
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Cnidaria |
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Abylopsis tetragona (Otto, 1823) |
5.4 ± 6. 37 |
7.98 ± 2.01 |
7.87 ± 4.54 |
15.1 ± 7.47 |
7.4 ± 2.6 |
3.97 ± 3.25 |
Agalma elegans (Sars, 1846) |
1 ± 1.73 |
0.4 ± 0.69 |
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Aglaura hemistoma Péron & Lesueur, 1810 |
0.55 ± 0.25 |
0.27 ± 0.46 |
0.16 ± 0.14 |
1.23 ± 1.36 |
0.21 ± 0.05 |
|
Chelophyes appendiculata (Eschscholtz, 1829) |
0.2 ± 0.35 |
1 ± 1.25 |
||||
Clytia hemisphaerica (Linnaeus, 1767) |
0.19 ± 0.31 |
0.27 ± 0.46 |
||||
Clytia spp Lamouroux, 1812 |
0.8 ± 1.06 |
0.27 ± 0.46 |
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Eucheilota paradoxica Mayer, 1900 |
0.27 ± 0.46 |
|||||
Hydractinia sp Van Beneden, 1844 |
0.27 ± 0.46 |
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Lensia subtilis (Chun, 1886) |
2.12 ± 2.38 |
0.9 ± 0.6 |
5 ± 1.82 |
18.17 ± 7.53 |
24.07 ± 14.99 |
|
Lensia subtiloides (Lens & van Riemsdijk, 1908) |
6.27 ± 9.78 |
2.27 ± 1.59 |
0.3 ± 0.3 |
0.8 ± 1.39 |
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Liriope tetraphylla (Chamisso & Eysenhardt, 1821) |
0.32 ± 0.42 |
0.64 ± 0.28 |
0.27 ± 0.46 |
|||
Lizzia blondina Forbes, 1848 |
2.16 ± 3.7 |
0.53 ± 0.46 |
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Mitrocomium cirratum Haeckel, 1879 |
0.13 ± 0.33 |
0.13 ± 0.33 |
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Muggiaea atlantica Cunningham, 1892 |
27.27 ± 21.02 |
4.12 ± 3.15 |
0.9 ± 0.52 |
44.17 ± 26.05 |
63.53 ± 14.56 |
22.7 ± 11.06 |
Muggiaea kochii (Will, 1844) |
1.18 ± 1.78 |
0.2 ± 0.35 |
0.2 ± 0.35 |
0.4 ± 0.69 |
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Nanomia bijuga (Delle Chiaje, 1844) |
4.9 ± 0.69 |
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Obelia spp Péron & Lesueur, 1810 |
0.4 ± 0.32 |
0.27 ± 0.46 |
0.61 ± 0.32 |
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Pelagia noctiluca (Forsskål, 1775) |
24.53 ± 57.82 |
3.85 ± 4.4 |
1.95 ± 2.09 |
10.93 ± 18.94 |
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Phialella quadrata (Forbes, 1848) |
0.27 ± 0.46 |
|||||
Proboscidactyla ornata (McCrady, 1859) |
0.27 ± 0.46 |
|||||
Rhopalonema velatum Gegenbaur, 1857 |
0.13 ± 0.33 |
0.45 ± 0.31 |
0.29 ± 0.12 |
0.93 ± 1.62 |
0.4 ± 0.21 |
0.45 ± 0.32 |
Solmaris sp Haeckel, 1879 |
||||||
Solmundella bitentaculata (Quoy & Gaimard, 1833) |
0.48 ± 0.26 |
0.29 ± 0.28 |
0.27 ± 0.46 |
0.37 ± 0.4 |
1.23 ± 0.88 |
0.27 ± 0.46 |
Sphaeronectes irregularis (Claus, 1873) |
1.7 ± 1.49 |
0.3 ± 0.52 |
1 ± 0.92 |
0.9 ± 0.79 |
2.8 ± 0.92 |
|
Chaetognatha |
||||||
Flaccisagitta enflata (Grassi, 1881) |
15.37 ± 12.47 |
24.75 ± 18.11 |
25.8 ± 13.25 |
61.07 ± 30.64 |
76.17 ± 49.93 |
122.67 ± 35.5 |
Mesosagitta minima (Grassi, 1881) |
0.03 ± 0.06 |
|||||
Parasagitta friderici (Ritter-Záhony, 1911) |
0.95 ± 1.11 |
2.65 ± 1.98 |
1.4 ± 1.42 |
11.43 ± 1.67 |
8.27 ± 3.71 |
23.07 ± 24.09 |
Pseudosagitta lyra (Krohn, 1853) |
0.07 ± 0.12 |
|||||
Pterosagitta draco (Krohn, 1853) |
0.1 ± 0.17 |
|||||
Tunicata |
||||||
Cyclosalpa affinis (Chamisso, 1819) |
0.05 ± 0.12 |
|||||
Doliolina krohni Herdman, 1888 |
7.05 ± 5.36 |
0.6 ± 0.52 |
0.6 ± 0.6 |
39.73 ± 47.61 |
8.5 ± 11.62 |
|
Doliolum nationalis Borgert, 1893 |
21.88 ± 7.27 |
23.27 ± 16.88 |
4.63 ± 1.96 |
12.73 ± 2.05 |
175.47 ± 23.67 |
66.07 ± 67.49 |
Fritillaria formica tuberculata Lohmann in Lohmann & Buckmann, 1926 |
3.85 ± 7.13 |
1.17 ± 1.04 |
0.1 ± 0.17 |
0.2 ± 0.35 |
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Fritillaria fraudax Lohmann, 1896 |
0.1 ± 0.17 |
|||||
Fritillaria pellucida (Busch, 1851) |
32.73 ± 13.19 |
3.38 ± 4.85 |
0.2 ± 0.35 |
23.63 ± 26.88 |
98.6 ± 27.37 |
2.6 ± 1.25 |
Kowalevskia oceanica Lohmann, 1899 |
0.6 ± 1.04 |
|||||
Oikopleura dioica Fol, 1872 |
18.42 ± 14.61 |
1.6 ± 1.26 |
2.3 ± 0.62 |
2.97 ± 4.63 |
5.03 ± 2.54 |
1.2 ± 1.04 |
Oikopleura fusiformis Fol, 1872 |
43.57 ± 30.1 |
1.55 ± 1.95 |
1.4 ± 1.65 |
0.1 ± 0.17 |
4.83 ± 2.8 |
12.03 ± 15.28 |
Oikopleura intermedia Lohmann, 1896 |
0.4 ± 0.46 |
2.77 ± 2.46 |
||||
Oikopleura longicauda (Vogt, 1854) |
75.35 ± 42.86 |
15.22 ± 12.75 |
6.3 ± 0.69 |
2.37 ± 3.06 |
30.4 ± 14.57 |
35.5 ± 50.29 |
Oikopleura rufescens Fol, 1872 |
0.95 ± 1.33 |
1.8 ± 1.83 |
2.6 ± 0.46 |
0.8 ± 0.92 |
0.4 ± 0.46 |
2.17 ± 3.25 |
Salpa fusiformis Cuvier, 1804 |
5.78 ± 10.43 |
0.4 ± 0.35 |
0.1 ± 0.17 |
|||
Thalia democratica (Forskål, 1775) |
88.92 ± 109.21 |
2.27 ± 2.44 |
3.57 ± 3.55 |
0.4 ± 0.69 |
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Mollusca |
||||||
Cavolinia inflexa (Lesueur, 1813) |
0.1 ± 0.24 |
|||||
Clio polita Pelseneer, 1888 |
0.8 ± 0.98 |
|||||
Creseis virgula (Rang, 1828) |
0.3 ± 0.5 |
0.8 ± 0.92 |
0.1 ± 0.17 |
|||
Heliconoides inflatus (d'Orbigny, 1835) |
2.38 ± 1.23 |
0.53 ± 0.43 |
0.5 ± 0.46 |
2.27 ± 2.15 |
6.5 ± 4.62 |
10.7 ± 12.3 |
Limacina bulimoides (d'Orbigny, 1835) |
0.6 ± 0.79 |
|||||
Limacina trochiformis (d'Orbigny, 1835) |
3.17 ± 2.61 |
6.7 ± 6.33 |
1.3 ± 1.35 |
4.07 ± 2.39 |
26.23 ± 8.95 |
8.3 ± 6.58 |
In the Habibas Islands, different abundances of marine organisms were observed depending on the taxonomic groups and seasons. For Tunicata, a minimum abundance of 126 ind.m-3 (HI6) and a maximum abundance of 468 ind.m-3 (HI4) were exhibited in May. In July, the minimum abundance was 19 ind.m-3 (HI4) and the maximum abundance was 93 ind.m-3 (HI6). The ANOVA showed a statistically significant difference between seasons for Tunicata (P < 0.05). In May, Chaetognatha showed a minimum abundance of 1 ind.m-3 (HI6) and a maximum abundance of 36 ind.m-3 (HI2). In July, the minimum abundance of Chaetognatha was 10 ind.m-3 (HI2) and the maximum abundance was 58 ind.m-3 (HI3). The ANOVA showed that there was no statistically significant difference in the abundance of Chaetognatha between seasons (P > 0.05). Regarding Cnidaria, in May, their minimum abundance was 15 ind.m-3 (HI6) and the maximum abundance was 160 ind.m-3 (HI1). In July, a minimum abundance of 13 ind.m-3 (HI1) and a maximum abundance of 25 ind.m-3 (HI6) were noted. The ANOVA showed a statistically significant difference between seasons for Cnidaria (P < 0.05). For Mollusca, in May, the minimum abundance was 4 ind.m-3 (HI4) and the maximum abundance was 12 ind.m-3 (HI2). In July, the minimum abundance was 2 ind.m-3 (HI2) and the maximum abundance was 16 ind.m-3 (HI3). The ANOVA showed that there was no statistically significant difference in the abundance of Mollusca between seasons (P > 0.05) (Fig.
At Sidi Fredj, a comprehensive analysis of the abundances of various groups across seasons demonstrated significant variations. ANOVA tests revealed significant differences (P < 0.05) in abundances between seasons within each group. For Chaetognatha, the highest abundance occurred in July at SF1 (202 ind.m-3), while the lowest was in November at SF2 (19 ind.m-3). In the case of Cnidaria, the peak abundance was observed in April at SF1 (118 ind.m-3), while the lowest occurred in November at SF3 (7 ind.m-3). For Mollusca, the maximum abundance took place in April at SF3 (46 ind.m-3) and the minimum was observed in November at SF3 (2 ind.m-3). Lastly, for Tunicata, the greatest abundance was observed in April at SF1 (406 ind.m-3), while the smallest was in November at SF2 (16 ind.m-3) (Fig.
At Habibas Islands, amongst the cnidarians, Pelagia noctiluca had the highest abundance with 24.53 (± 57.82) ind.m-3 in spring and 3.85 (± 4.4) ind.m-3 in summer (Table
Amongst the chaetognaths, Flaccisagitta enflata had a higher abundance of 15.37 (± 12.47) ind.m-3 in spring and 24.75 (± 18.11) ind.m-3 in summer. In contrast, Parasagitta friderici displayed an abundance of 0.95 (± 1.11) ind.m-3 in spring and 2.65 (± 1.98) ind.m-3 in summer.
Amongst the tunicates, Thalia democratica displayed a high abundance of 88.92 (± 109.21) ind.m-3 in May. In addition, Oikopleura longicauda had an abundance of 75.35 (± 42.86) ind.m-3 in May and 15.22 (± 12.75) ind.m-3 in July. Similarly, Doliolum nationalis showed a high abundance with 21.88 (± 7.27) ind.m-3 in May and 23.27 (± 16.88) ind.m-3 in July. Oikopleura fusiformis exhibited an abundance of 43.57 (± 30.1) ind.m-3 in May and 1.55 (± 1.95) ind.m-3 in July. Oikopleura dioica displayed an abundance of 18.42 (± 14.61) ind.m-3 in May and 1.6 (± 1.26) ind.m-3 in July. Moreover, Fritillaria pellucida had an abundance of 32.73 (± 13.19) ind.m-3 in May and 3.38 (± 4.85) ind.m-3 in July. Lastly, Fritillaria formica showed an abundance of 3.85 (± 7.13) ind.m-3 in May and 1.17 (± 1.04) ind.m-3 in July.
Amongst the Mollusca, Heliconoides inflatus exhibited the highest abundance with 2.38 (± 1.23) ind.m-3 in spring and 0.53 (± 0.43) ind.m-3 in summer. Following, Limacina trochiformis showed an abundance of 3.17 (± 2.61) ind.m-3 in spring and 6.7 (± 6.33) ind.m-3 in summer. In contrast, Cavolinia inflexa and Creseis virgula presented lower abundances of 0.1 (± 0.24) ind.m-3 and 0.3 (± 0.5) ind.m-3 in spring, respectively and were not observed in summer. Additionally, Clio polita showed an abundance of 0.8 (± 0.98) ind.m-3 in spring and was not observed in summer. Overall, the Mollusca showed lower abundances compared to other groups, with Heliconoides inflatus and Limacina trochiformis being the most abundant species.
At Sidi Fredj, significant seasonal variations were observed in cnidarian species abundances (Table
The Chaetognatha group showed varying abundance levels amongst the different species studied at Sidi Fredj. Flaccisagitta enflata emerged as the most abundant species, with its abundance increasing from 25.8 (± 13.25) ind.m-3 in November to 122.67 (± 35.5) ind.m-3 in July. Parasagitta friderici was the second most abundant species, with numbers ranging between 1.4 (± 1.42) ind.m-3 in November and 23.07 (± 24.09) ind.m-3 in July. In comparison, the other species, such as Mesosagitta minima, Pterosagitta draco and Pseudosagitta lyra, exhibited much lower abundances.
The Tunicata group exhibited a range of abundance levels for the various species studied. Doliolum nationalis was the most abundant species, with its abundance increasing from 4.63 (± 1.96) ind.m-3 in November to 66.07 (± 67.49) ind.m-3 in July. Fritillaria pellucida was another abundant species, with numbers ranging from 23.63 (± 26.88) ind.m-3 in March to 98.6 (± 27.37) ind.m-3 in April. Oikopleura longicauda also showed a significant presence, with its abundance increasing from 6.3 (± 0.69) ind.m-3 in November to 35.5 (± 50.29) ind.m-3 in July. Other species, such as Fritillaria formica, Fritillaria fraudax and Oikopleura rufescens, showed relatively lower abundances in comparison to the aforementioned species.
In the Mollusca group, a range of abundance levels was observed amongst the different species. Limacina trochiformis stood out as the most abundant species, with its abundance increasing from 1.3 (± 1.35) ind.m-3 in November to 26.23 (± 8.95) ind.m-3 in April and then decreasing to 8.3 (± 6.58) ind.m-3 in July. Heliconoides inflatus ranked as the second most abundant species, with its abundance ranging from 0.5 (± 0.46) ind.m-3 in November to 10.7 (± 12.3) ind.m-3 in July. The other species, such as Cavolinia inflexa, Clio polita and Creseis virgula, had much lower abundances in comparison (Table
The nMDS analysis emphasises the distinct groupings and unveils the dissimilarity between the Habibas Islands and Sidi Fredj (Fig.
ANOSIM pairwise comparison of gelatinous zooplankton abundance in the Algerian coast significance levels; *: <0.05 **: < 0.01; ***: < 0.001)
Regions |
Months |
Seasons |
R statistic |
Significance level % |
Habibas islands - Habibas islands |
May - July |
Spring- Summer |
1 |
0.002 *** |
Sidi Fredj - Sidi Fredj |
Mars - April |
Winter - Spring |
1 |
0.1 ns |
Sidi Fredj - Sidi Fredj |
Mars - July |
Winter - Summer |
0.704 |
0.1 ns |
Sidi Fredj - Sidi Fredj |
Mars - November |
Winter - Autumn |
1 |
0.1 ns |
Sidi Fredj - Sidi Fredj |
April - July |
Spring - Summer |
0.519 |
0.1 ns |
Sidi Fredj - Sidi Fredj |
April - November |
Spring - Autumn |
1 |
0.1 ns |
Sidi Fredj - Sidi Fredj |
July - November |
Summer - Autumn |
0.778 |
0.1 ns |
Habibas islands - Sidi Fredj |
May - March |
Spring - Winter |
0.981 |
0.012 ** |
Habibas islands - Sidi Fredj |
May - April |
Spring - Spring |
0.994 |
0.012 ** |
Habibas islands - Sidi Fredj |
May - July |
Spring - Summer |
1 |
0.012 ** |
Habibas islands - Sidi Fredj |
May - November |
Spring - Autumn |
0.981 |
0.012 ** |
Habibas islands - Sidi Fredj |
July - March |
Summer - Winter |
1 |
0.012 ** |
Habibas islands - Sidi Fredj |
July - April |
Summer - Winter |
0.988 |
0.012 ** |
Habibas islands - Sidi Fredj |
July - July |
Summer - Summer |
0.938 |
0.012 ** |
Habibas islands - Sidi Fredj |
July - November |
Summer - Autumn |
0.981 |
0.012 ** |
In the Habibas Islands (Fig.
In Sidi Fredj (Fig.
The purpose of this research was to broaden our understanding of gelatinous zooplankton along the central and western Algerian coast. This was achieved by examining the temporal patterns, taxonomy, occurrence and community structure of these organisms in the Habibas Islands and Sidi Fredj region, taking into account environmental factors. In total, 48 gelatinous zooplankton species were identified, most of which have been previously reported along the Algerian coast and in the western Mediterranean. This diverse group of species represents a cosmopolitan fauna, with some species being characteristic of Atlantic waters, such as M. atlantica and L. subtiloides (
Total abundances of zoological groups at Habibas Islands and Sidi Fredj vary from one month to another, not exceeding 500 ind.m-3, due to specific environmental factors in the region. The sampling stations are located in the Algerian Basin, where the Atlantic surface waters are offset by a westward countercurrent of deep Mediterranean waters (
In this study, redundancy analysis highlights a strong correlation between gelatinous zooplankton and temperature. As a result, temperature emerges as the most influential explanatory variable for certain cnidarian species. High water temperatures positively impact various stages of cnidarian reproduction, which can lead to rapid population growth and persistence throughout the winter season (
The warming of the epipelagic layer waters has been identified as having an impact on the behaviour of thaliaceans. D. nationalis is one of the species that exemplifies this trend, as noted by
Numerous studies (
The recently conducted study sheds light on the gelatinous zooplankton communities present along the Algerian coast. The research indicates that the Habibas Islands and Sidi Fredj exhibit a diverse range of species, with seasonal variations in both species richness and abundance. The study also emphasises the role of abiotic environmental conditions, including temperature, salinity and chlorophyll a levels, in regulating the population dynamics of these communities. The results underscore the significance of these factors in shaping the distribution and abundance of gelatinous zooplankton, which are essential components of marine ecosystems. This study contributes to a better understanding of the dynamics of gelatinous zooplankton communities in the south-western Mediterranean Sea, emphasising the importance of continued monitoring of these communities.
The implications of this study are critical for various stakeholders, including government officials, managers and fisheries scientists. The findings provide valuable information for designing policies and management strategies for sustainable fisheries, taking into account seasonal variations in zooplankton abundance and diversity. Government officials can use the results to create policies that aim to conserve the seasonal abundance of zooplankton and maintain healthy fish populations. Managers of fisheries can use this information to develop sustainable fishing practices that consider the seasonal variations in zooplankton abundance. Protective measures could be put in place during periods when zooplankton abundance is low to ensure adequate reproduction and growth of fish populations. These policies could include fishing quotas, marine protected areas or seasonal fishing restrictions.
Finally, our study may also benefit the scientific community studying fish. By understanding seasonal patterns in zooplankton abundance, researchers can better understand trophic interactions between fish and their prey, as well as the impacts of climate and environmental changes on marine ecosystems.