Lagocephalus suezensis Clark & Gohar 1953
Creators: name: Mutlu, Erhan
name: Meo, Ilaria de
name: Miglietta, Claudia
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Tetraodontiformes
Tetraodontidae
Lagocephalus
Lagocephalus suezensis

description: Lagocephalus suezensis
The most invasive species, L. suezensis, were abundant at all shelf stations with bottom depths of 10–to- 125 m (Fig. 6). Maximum average biomass was 300 kg /km 2 (Fig. 6A), and maximum abundance was 11,024 ind/km 2 (Fig. 6B). This species was abundantly present in all regions, particularly in R 4.
Regional differences were determined statistically for biomass distribution (p = 0.012). This difference was due to much higher biomass in R 4 (62.95 ± 16.31 kg /km 2) than in the other regions (2.75–10.09 ± 7.40 kg /km 2, Fig. 7A). The biomass was significantly different among seasons and bottom depths (p =0.448 and 0.269, respectively). Seasonal biomass varied from 1.59 ± 9.34 kg /km 2 in August to 19.57 ± 8.41 kg /km 2 in October (Fig. 7B). Biomasses were tended to decrease from shallower waters (24.32 -30.62 ± 10.04 kg /km 2) to deep waters (<2.00 kg/ km 2) (Fig. 7C). Depths greater than 125 m were virtually devoid of L. suezensis.
Overall, there were no significant differences in abundance among regions, seasons, and bottom depths (p = 0.084, 0.191, and 0.133, respectively, Fig. 6B). Abundance was significantly higher (2294.60 ± 762.64 ind/ km 2) in R4 than in the other regions (from 119.26 ± 355.58 ind/km 2 in R2 to 573.61 ± 334.44 ind/km 2 in R1). Maximum mean abundance occurred in October (1157.20 ± 376.87 ind/km 2), while minimum abundance occurred in August (56.24 ± 418.87 ind/km 2). Abundance decreased with bottom depth from high abundance in shallower waters (> 1000 ind/km 2 from 10 to 25 m and low abundance at greater depths (<100 ind/km 2 from 50–125 m).
Dominance of females over males did not differ among regions, seasons, and bottom depths (p = 0.611, 0.091, and 0.925, respectively). Regions R1 and R2 had sex ratios <2, whereas the ratios were higher in R3 (58.95 ± 33.85) and R4 (20.43 ± 61.79). The ratio was significantly higher (144.50 ± 49.03) in August than in the other seasons. Females predominated in bottom depths of 25 m (53.34 ± 33.82), then decreased to 0.14 ± 56.09 at 75 m; thereafter, no females were observed in the seaward direction.
Total length of L. suezensis varied between 4 cm and 18.5 cm during the year (Fig. 8A). The COST function estimated an optimum size class (bin size) of 0.52 cm for total length distribution of the species (Fig. 8B). The KDF determined five cohorts in total length: 4.0–5.5, 5.5–10.2, 10.2–14.3, 14.3–17.0, and> 17 cm (Fig. 8A). The third cohort was the dominant cohort in the population.
The lengths of the species were significantly different among regions, seasons, bottom depths, and sex (p = 1.3×10 -14, 2.5×10 -19, 2.0×10 -9, and 2.2×10 -27, respectively). The lengths were significantly shorter in R 1 (10.21 ± 0.19 cm) than the other regions (11.91 ± 0.18 to 12.44 ± 0.22 cm) (Fig. 9A). The shortest lengths differed significantly in October (10.59 ± 0.14 cm) and the longest individuals were present in February (13.01 ± 0.26 cm) (Fig. 9B). The lengths were significantly longer at bottom depths of 75 m (12.64 ± 0.44 cm) than lengths in bottom depths of 25 m (10.79 ± 0.15 cm) and 50 m (10.26 ± 1.13 cm, Fig. 9C). Females were significantly longer (12.37 ± 0.15 cm) than males (11.35 ± 0.14 cm); however, lengths of 8.35 ± 0.40 cm could not be sexed, and juveniles were 4.93 ± 0.96 cm in length (Fig. 9D).
Individual weight varied between 1.10 and 82.73 g. The weight changed significantly with the regions, seasons, bottom depths, and sex (p = 2.8×10 -11, 4.1×10 -16, 5.6×10 -6 and 7.5×10 -20, respectively). Individuals were significantly heavier in R 4 (27.50 ± 1.13 g) than in R 1 (16.88 ± 1.01 g) and R 2 (23.17 ± 1.52 g). The weight in May (25.39 ± 1.07 g) was significantly higher than in October (18.32 ± 0.75 g) and lower than in February (29.97 ± 1.35 g). Individuals were significantly lighter in weight in bottom depths of 25 m (19.59 ± 0.81 g) than at 10 m (25.64 ± 0.83 g) and 75 m (26.78 ± 2.34 g). Females were heavier (27.40 ± 0.81 g) than males on average (20.88 ± 0.75 g).
The total length relationship with weight of L. suezensis regressed significantly for the females, males, and total individuals (Fig. 10). The slopes of the regression lines were not significantly different from the isometric slope of 3 for total and female individuals, but significantly different for males (n = 522, t = -1.761; n = 280, t = -2.138; n = 239, t = -1.928, respectively) at p <0.05. This species grew in an isometric type of length-weight relationship.
Constants for the length-weight regression equations were significantly different by regions, bottom depths, and sex, including juveniles and individuals of undefined sex (p = 5.0×10 -7, 0.0022, and 0.0008, respectively); there was no significant difference among the seasons. The slopes and intercepts were not significantly different between males and females at p <0.05. The slope was significantly lower in R 2 than in the other regions, whereas they were not significant in R 1 and R 3 (Table 2). Regional differences were not estimated by post-hoc tests for length-weight relationships. Like the differences among sex (excluding undefined sex and juveniles), depth-wise differences in slopes and intercepts of length-weight relations were not significantly different; greater depths were excluded due to insufficient number of L. suezensis individuals.
description: Published as part of Mutlu, Erhan, Meo, Ilaria de & Miglietta, Claudia, 2020, Spatio-temporal distribution of pufferfish (Tetraodontidae) along the Turkish coast of the Mediterranean Sea Abstract, pp. 1-19 in Mediterranean Marine Science 22 (1) on pages 8-10, DOI: 10.12681/mms.23481, http://zenodo.org/record/12551720