Sebastes schlegelii Hilgendorf, 1880

Iftime, Alexandru & Oţel, Vasile, 2025, An annotated systematical checklist of the Romanian ichthyofauna, Zootaxa 5654 (1), pp. 1-64 : 36-38

Sebastes schlegelii Hilgendorf, 1880

A non-native native marine species, spread to Romanian Black Sea waters from introductions beyond the country (with ballast water or, likelier in our opinion, together with the oyster Magallana gigas , brought in for aquaculture 1 — Karpova et al. 2021; Ivanova et al. 2024); firstly found in 2022 when a juvenile specimen was photographed underwater (Marcoci, V., 2022 via Ichthyology of Romania Facebook group; Iftime id 2.; Fig. 10 ) then in 2023 when several specimens were captured ca. 2 miles off the harbour of Constanţa (Gherghe, M., 2023, via Marcoci, V., Ichthyology of Romania Facebook group; Marcoci & Iftime id.; Fig. 11 ) then in February 2024 in the Pescărie cove between Constanța and Mamaia (Bîlbă, A., 2024, via Ichthyology of Romania Facebook group; Niță & Oțel id.).

1 See, e.g., Krapal et al. 2019 for the introduction of Magallana gigas in the Black Sea.

2 Our first identification of this was as Epinephelus coioides (Hamilton, 1822) , but enhanced images and better available comparative images of juvenile S. schlegelii made us change our mind. See also Karpova et al. 2019 for a similar mistake (where S. schlegelii was taken for Epinephelus caninus ).

Fam. Gasterosteidae

Gasterosteus aculeatus Linnaeus, 1758

A native euryhaline species, found along all Romanian Black Sea waters, as well as in the Danube Delta, Razim lagoon complex, some littoral lakes and some inner waters (the Danube ca. 100 km upstream; the Siret up to Piscu, Galați county; the Prut). It migrates from the sea to coastal lakes, lagoons, Danube mouths etc., but also includes sedentary lacustrine populations ( Băcescu & Mayer 1956; Bănărescu 1964; Oțel 2007; Radu et al. 2008; Yankova et al. 2014; Țoțoiu et al. 2018; Cocan & MireȘan 2018; Niță et al. 2022). Nowadays rare in the sea (Oțel 2007 gives it as absent, but see Țoțoiu et al. 2018, and Niță et al. 2022, who still give it as present in the recent years), and recently not found in the Razim complex (Năstase et al. 2022). There are differences in morphology between the marine populations and some of the lacustrine ones ( Băcescu & Mayer 1956; Bănărescu 1964; Denys et al. 2015)—such is the case of Gasterosteus crenobiontus Băcescu et Mayer, 1956 , an endemic putative species, previously found in and area of freshwater springs at the inland end of lake Tekirghiol, isolated from the sea (and from marine G. aculeatus ) by the hypersaline waters of the lake. Described as a form of G. aculeatus ( Băcescu & Mayer 1956) , then treated as a subspecies ( Bănărescu 1964; Bănărescu 1994) then as a full species ( Kottelat 1997; Nalbant 2003; Kottelat & Freyhof 2007; Cocan & MireȘan 2018). However, this population was put in contact with the marine G. aculeatus when the Tekirghiol was freshened by irrigation outflows (presumably, in the 1970s-1980s), and it was merged into the marine-origin, typical-form G. aculeatus by massive crossing, showing biological conspecificity and erasing distinctness ( Bănărescu 1994; Bănărescu 2007 [does not mention crenobiontus , but only G. aculeatus ]).

Figures

FIGURE 10. Sebastes schlegelii, juvenile/subadult, photographed underwater at Mamaia, Black Sea, 2022, photo Valentin Marcoci (used here with permission).

FIGURE 11. Sebastes schlegelii, captured off Constanţa, Black Sea, 2023. A: detail of two specimens, photo Marian Gherghe (used here with permission). B: two specimens with associated capture, still frame from film by Marian Gherghe (used here with permission).