The sharpsnout seabream is a commercially valuable demersal member of the seabream family, the Sparidae, distributed from the Bay of Biscay and the Canary Islands through the Mediterranean and into the Black Sea. Historically more abundant in the Mediterranean, the species has been expanding northward in the Atlantic, a shift that researchers have linked to rising water temperatures. Its physiological toolkit helps explain this success: the fish tolerates water temperatures from 15 to 29 degrees Celsius and shows relative resistance to variation in oxygen availability, traits that would favor persistence under the notoriously variable conditions of the Black Sea. Reports from both the Sea of Marmara and the Black Sea in recent decades confirm that local populations are not just transient visitors but appear able to survive and reproduce in the basin, which represents the northernmost margin of the species’ known distribution.

Ecologically, D. puntazzo is typically found over rocky substrates and seagrass beds at depths from the surface down to 150 meters, though it is most common in the shallow infralittoral zone above 60 meters. Unlike some of its relatives, such as the white seabream D. sargus, which feed predominantly on benthic invertebrates, the sharpsnout seabream is omnivorous with a digestive system well adapted to herbivory. That dietary flexibility has already been on display in the southeastern Black Sea, where the species was previously observed opportunistically feeding on the egg capsules of the invasive veined rapa whelk, Rapana venosa, during the summer months. The new specimen adds a seasonal twist to that story.

Maximum body size matters in fisheries science because it underpins growth modeling, life-history assessment, and stock evaluation. Although the species can reportedly reach 60 centimeters in total length and live 10 to 18 years elsewhere, individuals exceeding 40 centimeters appear uncommon in the Black Sea. Prior regional records include a 41.6-centimeter, 1,007.2-gram specimen from Hopa, a 45.4-centimeter fish from Ordu, and a 44.5-centimeter individual from a broader morphometric study spanning Samsun to Hopa. Given the species’ growing presence in Turkish national fishery statistics, documenting rare large adults has real value for understanding regional growth potential, particularly because maximum length is closely tied to population dynamics assessments.

The methods behind the new record were deliberately rigorous. After capture, the specimen was transported to the laboratory on ice and weighed on a precision electronic balance accurate to 0.01 grams. High-resolution lateral photographs were taken with a scale reference using a Canon EOS R50 camera, and morphometric measurements were extracted digitally with ImageJ software following an established protocol. To guard against measurement error, total, fork, and standard lengths were recorded both manually and digitally, with the two approaches agreeing within 0.1 centimeters. Taxonomic identification followed standard references, sex was determined by macroscopic gonad examination, and the stomach was removed for dietary analysis. The meristic formula was recorded as D X, 14; A III, 12; P 14; V I, 6; C 20.

The numbers tell a nuanced story. The fish measured 47.6 centimeters in total length, 42.5 centimeters at the fork, and 39.5 centimeters in standard length. While the gain in length over the previous record is modest, the weight increase is substantial, and the explanation appears to be shape rather than reproduction. The specimen’s maximum body depth was 16.0 centimeters, compared with 13.6 centimeters in the earlier record fish from Ordu. Because the gonads were not prominent at the time of capture, even though November overlaps with spawning periods reported for some populations elsewhere, the researchers attribute the extra weight partly to this deeper body form and improved somatic condition rather than to ripening gonads. Regionally, the specimen surpasses maximum lengths reported from most Aegean studies and even exceeds the Adriatic maximum of 46.7 centimeters, though it remains below the Adriatic weight record of 1,545 grams.

The stomach contents delivered perhaps the most intriguing finding. Macroscopic examination revealed only macroalgae: the green alga Ulva rigida and red algae of the genus Ceramium, with no invertebrate prey at all. This late-autumn vegetarian meal contrasts sharply with the summer observations of rapa whelk egg capsule predation in the same region, suggesting that D. puntazzo exhibits genuine seasonal dietary flexibility in the Black Sea. For a recently established population, such flexibility could be a decisive advantage, allowing individuals to exploit whatever food resources are locally available as the seasons change. The authors also raise, cautiously, the possibility that coastal land reclamation and rock-fill structures along the southeastern Black Sea create artificial hard-bottom habitats offering shelter and feeding opportunities for reef-associated fishes, though they stress this interpretation remains hypothetical until dedicated habitat-use studies are done.

Equally significant is how the fish was caught. It was not taken by a trawler or a commercial net but by a recreational spearfisher, a selective method that targets individual fish. The researchers argue this hints that large specimens encountered in recreational fisheries may be underrepresented in conventional fishery records, potentially skewing our picture of the species’ true size structure in the basin. They are careful to flag the inference as preliminary, since a single opportunistic capture cannot establish how much recreational fishing contributes to total removals. Still, they call for dedicated monitoring of recreational catches, particularly spearfishing, alongside continued biological monitoring focused on size structure, habitat use, and fishery interactions rather than isolated maximum-size records alone.

The study’s limitations are clearly acknowledged. Everything rests on one specimen, so no population-level conclusions about size structure, growth rate, or abundance can be drawn. The fish’s age was not determined through otolith or scale reading, leaving its growth history and longevity unknown, and a single stomach sample reflects only recent late-autumn feeding rather than the species’ overall diet. The authors propose a research agenda to fill these gaps: systematic seasonal sampling, otolith-based age determination, quantitative diet analysis, habitat-use assessment, and monitoring of recreational catches.

Even with those caveats, the record matters. It confirms that large adult sharpsnout seabream do occur in the southeastern Black Sea, updates the regional maximum to 47.6 centimeters and 1,452 grams, and provides a biological reference point for future studies of growth potential, trophic ecology, habitat use, and fishery interactions in a species whose regional relevance is only growing. As warming waters continue to reshuffle marine communities across the Mediterranean basin and beyond, quietly tracking the giants of the fringe populations may prove one of the most informative windows into how species adapt, and thrive, at the edge of their range.

Subject of Research: New maximum size record and autumn feeding ecology of sharpsnout seabream in the Black Sea

Article Title: Unveiling the hidden stock: a new maximum size record for sharpsnout seabream ( Diplodus puntazzo ) from recreational fisheries in the Black Sea

Article References: Dokuzparmak, Ü., & Dürrani, Ö. (2026). Unveiling the hidden stock: a new maximum size record for sharpsnout seabream (Diplodus puntazzo) from recreational fisheries in the Black Sea. Scientific Annals of the Danube Delta Institute, 31, 15-23. https://doi.org/10.3897/saddi.31.196822

Image Credits: AI Generated

DOI: 10.3897/saddi.31.196822

Keywords: sharpsnout seabream, Diplodus puntazzo, Black Sea, size record, spearfishing, Sparidae, feeding ecology, macroalgae, Ulva rigida, invasive species, recreational fisheries, Trabzon