Spatio-temporal distribution of pufferfish (Tetraodontidae) along the Turkish coast of the Mediterranean Sea

Abstract

Pufferfish represent a serious threat to the marine ecosystem in the Mediterranean Sea. To better understand the population dynamics of pufferfish and their relation with ecological parameters, six pufferfish species were studied in two fishing and one non-fishing zone in one of the most oligotrophic regions of the Mediterranean Sea during 2014 and 2015, including different habitats of vegetated and non-vegetated and seasons. The results provide information on pufferfish ecological status compared with more eutrophic zones in which these species could potentially worsen their impact. Four species were common in the study area and two were rare. The dominant species was Lagocephalus suezensis, reaching abundances of 11,000 ind/km2 at 25 m in October, followed by Lagocephalus sceleratus, Lagocephalus guentheri, and Torquigener flavimaculosus. The rarest species, Tylerius spinosissimus and Sphoeroides pachygaster, reached higher abundance and biomass in October and February than the other sampling months. The riverine and meadow habitats played a crucial role for nursing and reproduction in the population dynamics of Lagocephalus species, while T. flavimaculosus was absent in these areas. Sex ratios changed depending on season and location. The occurrence of larger individuals of Lagocephalus spp. and T. flavimaculosus at greater depths evidenced an ontogenetic migration. Overall, length-weight (L-W) relationships indicate isometric growth for each of the species studied. Pufferfish populations were primarily a function of habitat and depth of seafloor and secondarily with water productivity.

The New Maximum Length and Depth of Lagocephalus guentheri Miranda Ribeiro, 1915 in the Mediterranean Sea

“…The individual is preserved in 50% ethanol solution and stored in the Istanbul University Science Faculty, Hydrobiology Museum (IUSHM 2021-1465). Mutlu et al (2021) mentioned that the length of the species shows a declining trend from shallow waters to deeper zones, and the longest individuals were observed at the depths of 75 m. It is not surprising for the individuals to reach a larger average size in such populations occurring in depths shallower than 60 m, due to the fact that there is not any industrial demersal fishing pressure in such depths, regarding the Mediterranean Sea. However, it is very unusual to obtain the species of this size from a depth of 128 m, a depth contour that is known to be under dramatic fishing pressure.…”

Nuevos registros y datos morfométricos y merísticos del conejo de hondura, Sphoeroides pachygaster (Tetraodontiformes: Tetraodontidae), en el suroeste del golfo de México

“…Por su parte, se revelan registros que corresponden a identificaciones erróneas; así, Ayala-Pérez et al (2015) mencionan a la especie en el sistema estuarino-lagunar de Palizada, Campeche; no obstante, al analizar detalladamente la figura que alude al ejemplar, esta corresponde a un juvenil de Sphoeroides parvus, que se puede reconocer por tener ojos en posición alta, las manchas y lunares de color marrón o gris, principalmente en los costados, y el lunar central de la axila pectoral de coloración menos intensa que el resto de lunares. Además, los juveniles de S. pachygaster son oceánicos y es la única especie del género Sphoeroides que tiene preferencia por aguas profundas (Mutlu et al 2021), lo cual contradice el reporte de Ayala- Pérez et al (2015).…”