Лимнология и биология пресноводных экосистем

New report of Craspedacusta sowerbii (Lankester, 1880) medusae in Belgium

Pajak, Joanne — 2026-02-19

The jellyfish Craspedacusta sowerbii (Lankester, 1880) is known to be an invasive species in freshwater worldwide, except in Antarctica. In Belgium, C. sowerbii was first recorded in 1939 by Damas in the River Meuse. Since then, few further Belgian observations of this species have been made. Here, we report the presence and determine the gender of C. sowerbii medusae in an artificial pond in Forrières, in southern Belgium. This is the first record of this species in the province of Luxembourg. Our findings suggest that the population consists exclusively of females.

Assessing the effects of dietary and waterborne commercial salt on the performance and welfare of common carp

Хама, Шамаль — 2026-02-19

This study investigated the effects of salt additives in water and diet on the physiological and health parameters of common carp (Cyprinus carpio L.). Fingerlings (~50 g) were divided into seven groups: a control group (G1), three water treatment groups (G2_A–_C; 4, 8, and 12 g L⁻¹ salt), and three diet treatment groups (G3_A–_C; 5, 10, and 15 g kg⁻¹ dietary salt). All fish were fed a standard diet containing 28% crude protein at 3% body weight per day. Results revealed that G1 had the highest values for lymphocyte and monocyte counts, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL), albumin, total protein, and several somatic indices. G2_B exhibited significantly higher potassium and sodium levels, while G3_A showed elevated white blood cell (WBC), granulocytes, liver enzyme activities (Alanine aminotransferase activity (ALT), aspartate aminotransferase activity (AST)), creatinine, glucose, chloride, and various somatic indices. G2_A and G2_Bgroups had increased red blood cells (RBC), hemoglobin, hematocrit, and body weight index. The findings indicate that using 12 g L⁻¹ salt in rearing water and 15 g kg⁻¹ salt in the diet can enhance growth and health performance in Cyprinus carpio. This study provides important insights into salt-induced physiological responses in carp and offers practical recommendations for aquaculture practices.

Influence of sex and body size on selected morphometric traits of Metopograpsus frontalis (Miers, 1880) from Southern Vietnam

Nguyen, Phuong — 2026-02-19

A total of 167 specimens of Metopograpsus frontalis (105 males and 62 females) were collected monthly from intertidal mudflats in Ganh Hao, Ca Mau Province, Southern Vietnam, from July to October 2025. Selected morphometric traits, including carapace width from left to right (CW_L–R), carapace width from right to left (CW_R–L), manus width (MW2, MW3), pollex width (PW5), and dactyl width (DW7), were measured with a 0.01-mm vernier caliper. Generalized linear models were fitted to evaluate the effects of sex and body size, using Gaussian models for CW and Gamma models with a log link for MW, PW, and DW. We found no significant sex-related differences in CW_L–Rand CW_R–L (p > 0.05), whereas MW2, MW3, PW5, and DW7 were significantly larger in males (p<0.001). Sex coefficients (β=0.156–0.257) corresponded to rate ratios (RR) of 1.17–1.29, indicating that male claws were 17–29% larger after adjusting for CW_L–R and CW_R–L. Both CW variables had strong positive effects (β=0.054–0.070; RR=1.06–1.07; and p<0.001). All Gamma models showed χ²/df<1, confirming good model fit without overdispersion. These results provide quantitative evidence of sex-related variation in morphometric traits of M. frontalis and establish a morphometric baseline for future ecological and evolutionary studies of mangrove crabs in the Mekong Delta.

Nanozinc as an emerging nanopollutant: sublethal effects on the invasive freshwater bivalve Limnoperna fortunei (Dunker, 1857)

Ale, Analía — 2026-02-19

Zinc oxide nanoparticles (ZnONP) are among the most widely produced nanomaterials worldwide given their unique properties, despite their nanotoxicity has been poorly addressed. In parallel, environmental concern has risen because of increasing amounts of them reaching the environmental matrices, whereas the aquatic ones are one of the main final sinks. As key non-target species, we aimed to expose the invasive freshwater bivalve Limnoperna fortunei to sublethal concentrations of ZnONP (0, 0.025, 0.25, and 2.5 mg/L) to evaluate tissue damage and oxidative stress-related markers in the soft tissue. After a 96 h-exposure, the alkaline phosphatase enzyme activity increased after 0.025 mg/L, and the alanine aminotransferase activity decreased at 2.5 mg/L. Aspartate aminotransferase enzyme activity also decreased at 0.25 and 2.5 mg/L. In terms of oxidative stress, only superoxide dismutase activity increased after exposure to the lowest nanozinc concentration. We concluded that nanozinc may pose a threat to the aquatic biota in a context that lacks proper regulation and control for nanopollutants, and that the toxicity mechanisms in this species are mainly related to tissue damage, even at environmentally relevant concentrations, as the lowest one tested.

Morphometric analysis of selected claw traits in Tubuca forcipata (Ocypodidae) from Southern Vietnam

Dai, Vinh — 2026-02-19

A total of 233 specimens of the fiddler crab Tubuca forcipata (189 males and 44 females) were collected monthly from intertidal mudflats in Dam Doi and Hoa Binh, Ca Mau Province, Southern Vietnam, from July to October 2025. Selected morphometric traits, comprising the carapace width left-to-right (CW_L–R), the carapace width right-to-left (CW_R–L), the manus widths (MW2 and MW3), the pollex width (PW5), and the dactyl width (DW7), were measured to 0.01 mm. Generalized linear models with a gamma distribution and log link were used for trait comparisons; cheliped traits were analyzed with sex and the carapace width (CW_L–R or CW_R–L) as predictors. The carapace width did not differ by sex (p > 0.05), whereas MW2, MW3, PW5, and DW7 were significantly larger in males after adjusting for the carapace width (β_sex = 0.156–0.257; rate ratios (RR) = 1.17–1.29; p < 0.001). The carapace width had strong positive effects on all cheliped traits (β_CW = 0.054–0.070; RR ≈ 1.06–1.07; p < 0.001). Model diagnostics showed χ²/df < 1, indicating no overdispersion. These results demonstrate pronounced sex-linked functional dimorphism in the chelae of T. forcipata despite similar overall body size, providing a quantitative morphometric baseline for ecological and evolutionary studies of mangrove crabs in the Mekong Delta.

Изменчивость плодовитости пеляди Coregonus peled (Gmelin, 1789) Средней Оби (Западная Сибирь) и влияние на нее температуры окружающей среды

Mishakin, Alexander — 2026-02-19

Пелядь Coregonus peled – широко распространенный представитель сем. Coregonidae в Северной Евразии, численность которого до сих пор относительно высока на всех участках бассейна Оби. Вид отличается экологической пластичностью, его плодовитость варьирует в очень широких пределах, различаясь как в разных водных объектах, так и в одном и том же в разные периоды наблюдений. Известно, что на воспроизводительную способность данного вида оказывает влияние гидрологический режим – в многоводные годы она выше. Целью данной работы был анализ плодовитости пеляди, поднимающейся для естественного воспроизводства в пределы Средней Оби, и поиск связи ее колебаний с температурой среды. Выявлено, что половая зрелость среднеобского стада пеляди начинает наступать в трехлетнем возрасте, однако его основу составляют пяти–шестилетние экземпляры, суммарно составляющие до 70 % производителей. Показатели воспроизводительной способности вида весьма изменчивы. Индивидуальная абсолютная плодовитость составляет от 11,3 до 58,0 тыс. икринок, увеличиваясь с возрастом, промысловой длиной, общей массой, массой тела без внутренностей, упитанностью по Фультону и по Кларк. Индивидуальная относительная плодовитость колеблется от 36 до 103 икринок на грамм массы тела и коррелирует с общей массой рыб и упитанностью по Фультону. При этом показатели воспроизводительной способности пеляди существенно различаются в разные годы. В целом в настоящее время индивидуальная относительная плодовитость данного вида в возрастных группах 5+ и старше по сравнению с серединой ХХ века снизилось на 41–47 %. Отмечена связь воспроизводительной способности пеляди, поднимающейся на нерест в Среднюю Обь, с температурой среды в Нижней Оби, где происходит нагул производителей перед началом нерестовой миграции – относительно высокие температуры июля ассоциированы с более низкими показателями ИАП наиболее многочисленных возрастных групп. Таким образом, потепление климата может отрицательно сказаться на воспроизводительной способности пеляди в бассейне Оби.

Trophic structure and functional feeding groups of macroinvertebrates in a section of the Gallinazo tropical stream

Saldaña Escorcia, Rossember — 2026-02-19

Aquatic macroinvertebrates play crucial roles in ecosystem processes such as grazing, decomposition, and mineralization. Classifying these organisms into functional feeding groups (FFGs) enables a more comprehensive understanding of energy and matter flow through trait-based approaches, complementing traditional taxonomic methods. The study analyzed the trophic structure and FFG variation of aquatic macroinvertebrates in a section of a tropical stream, located in the municipality of Aguachica, Colombia. Sampling was carried out during the rainy season in May and the dry season in July 2024, during which the composition and abundance of macroinvertebrate feeding groups were analyzed. Physical and chemical parameters were measured both in situ and ex situ at strategically selected stations based on accessibility and location. Macroinvertebrates were collected using Surber and D-type nets and identified to the family level. They were then assigned to functional feeding groups. Ecological indices and multivariate statistical analyses were applied to evaluate ecosystem attributes. Results revealed seasonal variations in water parameters, including lower dissolved oxygen and higher chemical oxygen demand during the dry season, suggesting potential organic pollution. Macroinvertebrate richness was higher during the dry season, with Caenis sp. and Tanypodinae sp. being dominant, while Drepanotrema sp. and Physa sp. were more abundant during the rainy season, reflecting eutrophic conditions. The P/R index indicated heterotrophic dominance, and low CPOM/FPOM ratios pointed to limited riparian cover. These findings underscore the importance of implementing conservation strategies to mitigate anthropogenic pressures and preserve the ecological integrity of freshwater ecosystems.

Bioactivities of freshwater sponges and their associated bacteria: a review

Adkar, Unmesh — 2026-02-19

This review aims to provide an overview of the biological activities of freshwater sponges and their microbes associated with them. Freshwater sponges, despite their ecological significance and potential as reservoirs of bioactive compounds, remain underexplored compared to their marine counterparts. This review highlights the bioactivities of eight freshwater sponge extracts, among them being Ochridaspongia rotunda (Arndt,1937), Ephydatia fluviatilis (Linnaeus,1759), Oncosclera asiatica (Manconi & Ruengsawan,2012), Metania reticulata (Bowerbank,1863), Drulia browni (Bowerbank,1863), Drulia cristata (Weltner,1895), Drulia uruguayensis (Bonetto & Ezcurra de Drago,1969), and Eunapius carteri (Bowerbank,1863).Various extracts, including those obtained using methanol, acetone, aqueous, ethyl acetate, and methylene chloride, were employed in previous studies to evaluate a range of bioactivities. Observed bioactivities include antibacterial, antifungal, anti-quorum sensing, antiplasmodial, acetylcholinesterase inhibition, and anticancer properties, which are determined either from the crude extracts of the sponges themselves or by their associated microbes.