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    • Water lettuce and water spinach as potential feed ingredients for Nile tilapia Oreochromis niloticus

      Manuel, Eljhon; Gutierreez, Regie; Naorbe, Marissa (2020-07-01)
      Nile tilapia (Oreochromis niloticus) is an omnivore and is considered as one of the important aquaculture commodities. Different plant-based ingredients like corn, “ipil-ipil” leaves and even micro and macroalgae were already tested to reduce the cost on the use of animalbased protein source. This preliminary study therefore, is an attempt to assess the potential of water lettuce and water spinach as feed ingredients through average body weight (ABW), specific growth rate (SGR), survival rate and feed conversion ratio (FCR) of juvenile O. niloticus. Three treatments [water lettuce (WL), water spinach (WS), water lettuce and water spinach (WL+WS)] were prepared in the form of three different diets [Diet 1 (1:1 water lettuce: fish meal), Diet 2 (1:1 water spinach: fish meal) and Diet 3 (1:0.5:0.5) (fish meal: water lettuce: water spinach)] each replicated thrice and fed to tilapia for 60 days. Tilapia growth showed no significant differences in all diets. The diet with water spinach (Ipomoea aquatica) significantly improved the SGR. Based on the result, the I. aquatica could be included both in a simple or complex diet together with water lettuce (Pistia stratiotes). It took 30 days for O. niloticus to adjust to the introduced diets as reflected to their survival rate but the FCR was higher when fed with the test diets compared to the recorded commercially-fed tilapia. Overall, I. aquatica has an excellent performance for O. niloticus culture.
    • Note on the availability of Philippine Forest Turtle Siebenrockiella leytensis in online reptile markets

      Janssen, Jordi; Sy, Emerson (2020-07-01)
      The Philippine Forest Turtle Siebenrockiella leytensis is a critically endangered species endemic to the Palawan group of islands, where it is better known under the English name of Palawan Forest Turtle. No permits have been issued by the Philippine authorities to collect and/or trade in native live wild-caught reptiles since 2001, yet, the trade of captive-bred individuals is allowed. Regardless, evidence of this species breeding in captivity is very scarce and limited to two documented events. Although strictly protected, illegal trade seems to continue with sightings of this species in China, USA, and Europe. Here we report the results of a six-month survey in nine countries/regions carried out to estimate the availability of this species in the online pet trade. We monitored over 60 social media platforms (e.g. Facebook groups, MeWe) and reptile classified websites in Europe, United States of America, Malaysia, Japan, China, Taiwan, South Korea, Hong Kong SAR and the Philippines between 1 February 2019 and 31 July 2019. Only one advertisement offering two Philippine Forest Turtles was observed during the study period. On 30 June 2019, two adult Philippine Forest Turtles were offered for sale in a Japanese pet store. In addition, an advertisement was found outside the study period in Hong Kong, suggesting that there is still international demand for this critically endangered species.
    • First record of Thalassina kelanang (Crustacea: Decapoda: Thalassinidae) from the Philippines

      Albarico, Frank Paolo Jay; Gacutan, Rogelio; Bedi, Agatha Maxine (2020-07-01)
      The first record of mud lobster Thalassina kelanang (Moh and Chong, 2009) from the Philippines was documented in the mangrove forest of Suyac Island, Sagay City, Province of Negros Occidental. The male specimen with a total length of 16.5 cm and 4.5 cm carapace width was found surfacing the mangrove substrate in January 2019. Further survey yielded two more specimens. The specimens had an obtuse rostrum, and a deep median sulcus, which extends posteriorly, nearly the same length but behind the adrostral carinae. The slenderly elongate petasma bears conspicuous spines in the proximal lateral margin. The mounds of T. kelanang with heights ranging from 5 to 15 cm were smaller compared to those of Thalassina anomala. This is the fourth Thalassina species reported from the Philippines.
    • Antimicrobial property of the epidermal mucus of Tilapia Oreochromis spp.

      Sajorne, Recca; Mabuhay-Omar, Jhonamie (2020-07-01)
      This study was conducted to determine and compare the antimicrobial property of the epidermal mucus of Tilapia (Oreochromis spp.) from two environmental conditions, the fish tank and fishpond. The antimicrobial property was determined using Filter Paper Disc Diffusion Method with Amoxicillin and Nystatin as the positive controls and distilled water as the negative control. Results showed significant differences in the effects of the treatments when tested against Escherichia coli, Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger and Aspergillus flavus (p<0.05). The Duncan’s Multiple Range Test further proved that the mucus of Tilapia from fishpond was significantly higher in terms of antibacterial property compared to mucus of Tilapia from fish tank. On the other hand, both of the epidermal mucus of Tilapia from fishpond and fish tank did not show any inhibitory effect against P. aeruginosa and A. niger. The epidermal mucus of Tilapia showed bacteriostatic, fungistatic and bactericidal effects against test microorganisms. Based on the results, the mucus of Oreochromis spp. from fishpond and fish tank are potential sources of antimicrobial compounds.
    • High density of Tridacna crocea in Rita Island, Puerto Princesa City, Palawan, Philippines

      Daño, Jemima; Villanueva, Elmer; Dolorosa, Roger (2020-07-01)
      In spite of being a protected species in the Philippines, the Tridacna crocea or crocus clam, the smallest among eight known giant clam species in the country, is getting rare in most reef areas of Palawan. However, a high density of this species has recently been noted in Rita Island, Ulugan Bay. A total of 44 photos with known dimensions having a total area of 13.26 m2 suitable habitats with clams were analyzed for size structure and density of T. crocea. In total, 215 T. crocea were noted with 84.91 (±25.6) mm average shell length (±sd). The average density (±sd) was 16.22 (±15.75) individual (ind)∙m-2 but the clams had occurred up to 17 individuals in 0.28 m2 or 59.91 ind∙m-2. This high density of T. crocea could be due to suitable environment and the absence of exploitation within the vicinity of the island resort. The importance of other resorts in biodiversity conservation may be investigated.
    • Commonly gleaned macro-benthic invertebrates in a small offshore island of Cawili, Cagayancillo, Palawan, Philippines

      Ardines, Randy; Mecha, Niño Jess Mar; Dolorosa, Roger (2020-07-01)
      The inhabitants of small offshore islands are highly dependent on the health and availability of their resources. However, pieces of information about the commonly gleaned species in some remote areas are sparsely documented. In this study, we inventoried the species composition of the widely gleaned macro-benthic invertebrates such as gastropods, bivalves, and sea cucumbers in Cawili Island, a small inhabited island in the middle of the Sulu Sea in Palawan, Philippines. The samples obtained from fishers and snorkeling activities in shallow areas revealed a total of 85 species belonging to 27 families. Most of these were gastropods, composed of 68 species under 20 families. The list includes nine protected species (four gastropods, two bivalves, and three sea cucumbers). Gastropods and bivalves were mostly used for food and display in the house of the fishermen (souvenir), while the sea cucumbers were exclusively harvested for trade. Sustainable fishery activities are needed in this small offshore island where people heavily rely on their marine resources.
    • Teset

      Teset; Test (2020)
    • Ocean science, data, and services for the UN 2030 Sustainable Development Goals.

      Schuckmann, Karina von; Holland, Elisabeth; Haugan, Peter; Thomson, Peter (2020)
      Relating the Sustainable Development Goal (SDG) 14 for Ocean and Life Below Water to the 16 remaining SDGs in the UN 2030 sustainable development agenda. A holistic approach that embraces sustainable Ocean stewardship informed by best available science, data and services to support society and the economy is required to create the ‘Future We Want’. The UN Decade of Ocean Science for Sustainable Development is an essential foundation to achieve this objective.
    • Drivers of spatio-temporal dissimilarity in community composition: temporal changes in land use and environmental heterogeneity.

      Peláez Zapata, Oscar Eduardo (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2020)
      Biodiversity encompasses multiple aspects or facets changing in space and time. Before a loss of biodiversity in response to anthropogenic impacts it is of the utmost importance to determine what facets of biodiversity are altered and the determinants of such changes. By using information from species abundance, their evolutionary relatedness, and ecological traits we determine how the dissimilarity in composition of fish communities is influenced by temporal changes in land use and changes in environmental heterogeneity across space. In the first approach, we can see that changes in land use over time affected mainly the substitution of evolutionary lineages and functional traits. In the second approach, we find evidence of taxonomic and functional homogenization over time, likely following a decrease in diversity of traits related to habitat use. Furthermore, we found that ecological traits contributed differently to the changes in functional composition as well in their response to environmental heterogeneity. These results support recently evidence showing that anthropogenic impacts are driving changes in biological communities through a taxonomic and functional homogenization.
    • Variáveis relacionadas com a distribuição regional, dominância e estruturação de comunidades de peixes em riachos.

      Oliveira, Fagner Junior Machado de (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2020)
      Different ecological processes (e.g., rescue effect, environmental filtering, limiting similarity and dispersal) shape the structure of ecological communities. These processes, which are related to the theories of metapopulation and metacommunities, guided this study. For this purpose, data from fish communities in streams in the Upper Araguaia river basin (Mato Grosso and the Goiás States, Brazil) were used. It was observed that the regional distribution of fish species was modelled according to niche attributes (position and breadth), body size, trophic position, and swimming capacity. The results indicated that average abundance, niche position and niche amplitude predict the regional distribution of the species. Taken together, these results suggest the importance of metapopulation dynamics and niche-based processes explaining the regional distribution of species in the studied system. At another time, it was tested whether the abundance of subordinate species (i.e., any species that are not dominant in a local community) was correlated with the functional distance between dominant and subordinate species. In the results, a negative relationship between these quantities and that the subordinate species had larger body sizes compared to the dominant species in the local communities. These results also suggest that species filtering is more important than the interspecific competition to explain the patterns of species abundance distribution. In this study, was analyzed the relative importance of local environmental, landscape and spatial variables in structuring fish communities in streams of “veredas” (small wetlands in the Cerrado). The local environmental variables, after controlling the effect of space, were clearly more important than those obtained at the landscape scale. In view of the observations, it is concluded that the use of landscape data, in studies seeking environmental correlates of local community structure, should not occur at the expense of obtaining local variables (mainly those related to the habitat structure). The results of the three investigations in this study shown the predominant role of local environmental filters in the structuring of the fish communities analyzed. Species with high niche amplitude tend to have wide regional distributions and small-bodied ones tend to be locally dominant.
    • Predação e estruturação de habitat por macrófitas modificam a diversidade taxonômica e funcional do zooplâncton.

      Deosti, Sabrina (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2020)
      In Neotropical rivers the predation by fish and the structuring of the habitat by macrophytes influence the dynamics of the zooplankton community, altering the richness and composition of species and the richness and functional composition of the zooplankton and thus the functioning of the ecosystem. We analyzed the influence of macrophytes bank structure and predation by forage fish species on taxonomic and functional zooplankton diversity, estimated by different diversity indices (taxonomic and functional richness, taxonomic beta diversity and functional beta diversity). Thus, we assume that different levels of macrophytes structure and fish predation will alter the taxonomic and functional composition of the zooplankton (alpha and beta) between the analyzed points. Beta diversity was split into two distinct components, turnover and nesting. The zooplankton species richness was positively associated with the macrophytes richness and the macrophytes diversity. In turn, the functional richness of zooplankton had a positive association with fish richness and macrophytes richness. For the variation of total taxonomic beta diversity of zooplankton, the Generalized Dissimilarity Modeling (GDM) explained 32.58% of the total among the predictor variables. The macrophytes biomass represented the taxonomic turnover. The variation in total functional beta diversity of the zooplankton explained 9.98% by the GDM model. The abundance of fish represented the functional nesting. Macrophytes structure represented the taxonomic components and predation represented the functional components. The limnological heterogeneity of the coastal region of the Bay River made possible the colonization by multispecies macrophytes banks, influencing the alteration of the fish and zooplankton community and the more heterogeneous the environmental conditions, the greater is the capacity of colonization of different species, which can present different functional traits. The results indicate the importance of maintaining heterogeneous locations, the need to preserve the tributaries in river floodplain systems as they serve as nursery for fish spawning and contribute to a greater richness of fish, which causes an increase in the functional diversity of zooplankton.
    • Effects of dam operation on stability, species interactions, and the mechanisms underlying the synchrony of fish in reservoirs.

      Baumgartner, Matheus Tenório (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2020)
      The construction of dams is among the main anthropogenic impacts in natural freshwater systems. The first consequence of impoundments is the formation of reservoirs upstream, which represents a completely new environment compared to the natural river. In addition to this primary impact, the variations in the reservoir water level may be considered another facet of disturbances. Although several studies investigated the processes that occur in reservoirs, there is a shortfall regarding the effects of the dam operation scheme on ecosystem health. Most dams are designed to operate under two almost contrasting schemes: storage (STR) and run-of-river (ROR). These alternative operation schemes result in very different temporal variations, with STR reservoirs presenting rapid fluctuations while ROR reservoirs have a relatively constant volume. Likewise, this difference in the temporal dynamics of water level likely affects the stability of these ecosystems. In order to investigate how the dam operation scheme could affect the temporal stability of freshwater ecosystems, we used the fish communities from two reservoirs in the Iguaçu River that operate under contrasting schemes. The hypothesis was that the STR reservoir would be less stable, considering the environmental heterogeneity created by frequent water level variations, and the interactions among species would be less important for the structure of the resident fish community. In the first approach, the focus was on stability in terms of the ability to resist and recover (i.e., resistance and resilience) to disturbances. In the second approach, empirical data and simulations were used to assess which mechanism (species interactions, environmental or demographic stochasticity) underlie the synchrony of fish communities. Contrary to the expectation, the results showed the ROR reservoir as less stable than the STR, and the mechanisms underlying species synchrony coincided between reservoirs but played opposite roles. More specifically, the temporal dynamics imposed by ROR operation may have weakened the species-environment relationships, which led to a less stable community. Although the results were consistent, they were only primary evidence and such cause-effect relationships between dam operation and its effects on ecosystem stability require further investigations.
    • Abordagem multimétrica na avaliação da integridade ecológica : fundamentos conceituais e aplicações.

      Ruaro, Renata (Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais., 2019)
      The use of multimetric indices (MMIs) to assess ecological conditions in aquatic environments has been applied globally. These indices are practical tools that incorporate various biotic metrics at different levels of biological organization. However, criticism has been directed to the use of MMIs, especially regarding the methodological criteria applied in the process such as related to metric selection and scoring and identification of reference conditions that consider all sources of ecological integrity disturbance. A review of the scientific literature was carried out to evaluate processes of creation and validation of MMIs worldwide. The criteria used by scientists to identify reference conditions, metric selection and scoring, the main metrics globally used in MMIs, and the challenges in applying these indices were verified. It was identified whether nonnative species have been considered as a source of degradation of ecological integrity in the MMIs application. The results indicated that there are no common criteria for determining reference conditions, for metric selection and scoring, which makes it difficult to compare different programs and regions, and to develop or improve future MMIs. The results showed that metrics related to species richness were most frequently used in MMIs applied worldwide, thus, it represents a consistent response pattern in the assessment of ecological conditions. The results also indicate that differentiating natural variability from anthropogenic impacts was evidenced as the major challenge in the MMIs creation and application. The review of the scientific literature indicated that biological invasions are neglected in ecological integrity assessments, as nonnative species are rarely considered as a disturbing factor in identifying reference conditions and species origin metrics are not widely used in MMIs. The results presented in this review may promote the advancement and improvement of MMIs as bioassessment tools.
    • Assessment of water and bottom sediment pollution with heavy metals and arsenic in the Caucasus Region of the Black Sea at the present time

      Evseeva, A.I.; Korablina, I.V.; Gevorkyan, Zh.V.; Katalevsky, N.I.; Gorgola, L.G.; Bragina, T.M. (2020)
      The content of nine heavy metals (Fe, Mn, Zn, Cr, Cu, Pb, Cd, Hg, Ni) and arsenic in the water and bottom sediments of the North-Eastern Black Sea at the present time (2018–2019) has been estimated, and the results of this investigation are presented. The analyses of samples, collected during the multi-purpose expeditions of the Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”) in the spring – early summer and summer – early autumn seasons, are summarized. Altogether, 204 water samples and 60 bottom sediment samples have been collected. Estimation of mass concentrations of heavy metals and arsenic has been conducted according to the methods, developed and adopted by the Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”). Pollution levels in the habitat of aquatic living resources have been assessed based on the standards for maximum allowable concentrations (MAC) of harmful substances in water bodies of fisheries importance and on the average long-term values. In some areas, subjected to the increased anthropogenic pressure, exceedance in MAC of iron, manganese, zinc, and nickel is recorded. It is shown that, at present, the revealed content of heavy metals and arsenic in the water and bottom sediments of the investigated area of the Caucasus Region of the Black Sea does not pose a threat for the aquatic living resources.
    • Specific features of the change in the statistical characteristics of the horizontal structure of the salinity field of the Azov Sea waters

      Panov, B.N.; Spiridonova, E.O.; Bragina, T.M. (2020)
      The work is based on the data from 49 spring, summer and autumn oceanographic surveys carried out by the Azov-Black Sea Branch of FSBSI “VNIRO” (“AzNIIRKH”) in the Azov Sea from 2001 to 2016. As characteristics of the horizontal structure of the salinity field, the radii of the concentration region of the spatial correlation function of the field in the zonal and meridional directions in the surface and bottom horizons were calculated, as well as their ratio reflecting the prevailing direction of water exchange. The average size of meridional radii was 42 km, and for the zonal one it was equal to 46 km. It is shown that, in the surface layer, the radii are maximum in summer and minimum in spring; in the bottom layer they decrease mainly from spring to autumn. The zonal radius prevails in the surface layer of the sea, whereas the meridional one prevails in the bottom. In the trends of long-term changes in the surface layer, the sizes of the meridional radii have increased. In the bottom layer, the zonal radii were decreasing. The years of predominance of zonal radii in the structure of the salinity field were attended with a decrease in the average salinity of the sea, and the predominance of meridional radii was associated with its increase. An almost complete absence of statistically significant relationships between the characteristics of the field, both in seasonal and in average annual values, was noted.
    • Status of the Chamelea gallina and Pitar rudis communities in the North-Eastern Black Sea in the autumn of 2019

      Frolenko, L.N.; Zhivoglyadova, L.A.; Bragina, T.M. (2020)
      Spatial distribution and quantitative characteristics of the main bottom communities in the North- Eastern Black Sea, characterized by the prevalence of the native bivalve species Chamelea gallina and Pitar rudis, have been considered for the autumn season of 2019. Within the investigated region, at the depth of 18 m,the largest area of sandy biotopes with silt and shell admixture was occupied by a community dominated by the bivalve mollusc Ch. gallina. At the depth of 30 m, a community of the pelophilic bivalve mollusc P. rudis was observed on silty substrate with shells and, at times, sand admixture. In the Chamelea community, molluscs were the most prominent group in terms of abundance and biomass. In the Pitar community, polychaetes were the most abundant in the benthic community, while molluscs prevailed in terms of their biomass. If compared with the data of the 1960s, the contemporary analysis of the materials presented indicates a decrease in the biomass of the macrozoobenthos down to 93 g/m2 and of the dominant species down to 41 g/m2 in the Chamelea community, which is associated with the predominance of small individuals in the mollusc populations. In the autumn of 2019, despite the appearance of invading species, the native species prevailed in the main regional biocoenoses.
    • Dynamics of water quality in the Temernik River considering the toxicity levels based on the data of the biotest battery

      Bakaeva, E.N.; Taradayko, M.N.; Ignatova, N.A.; Zaporozhtseva, A.Yu.; Bragina, T.M. (2020)
      The urbanized section of the Temernik River (Rostov-on-Don, Southern Federal District) is subjected to anthropogenic pressure. During the investigation of water toxicity by means of the bioassay method, an obvious disadvantage of using one biotest was revealed. Recently, a biotests battery has been used. However, assessing toxicity based on only one, most sensitive biotest, is untenable. The toxicity assessment has been carried out according to the scale developed by the authors. The scale considers the results of the assessment of toxicity level according to each biotest, and classifies water quality in concordance with the classes adopted in hydrochemistry. The water quality of the Temernik River has been assessed by means of the bioassay method according to a set of practices, taking into account the toxicity levels for each of the applied biotests. The studies were carried out in 2017–2019. The cultures of Chlorella vulgaris, Raphanus sativus (phytotest), and Daphnia magna were used. The water of the Temernik River showed a wide range of toxicity from “low” toxic (2 “a” class) to “extremely” toxic (5 class). The dynamics of water quality was characterized by the increase in toxicity from 2017 to 2019. The highest degree of water toxicity was recorded at the mouth of the Temernik River, in the Don River downstream from the mouth of the Temernik River, and near the Botanical Garden of the Southern Federal University at the storage site for extracted bottom sediments. Biotest data are confirmed by the analytical data on water pollution.
    • Assessment of caesium-137 accumulation in the bottom sediments and aquatic bioresources of the Azov Sea at the present time

      Mkhitaryan, I.D.; Korablina, I.V.; Bragina, T.M. (2020)
      The results of radioecological investigation of the bottom sediments in the Azov Sea are given for 2017–2019. Pollution of the Azov Sea bottom sediments during the period under study has been detected sporadically and is determined by redistribution of predominately post-Chernobyl fallout. The level of caesuim-137 pollution of the bottom sediments has been evaluated in comparison with its long-term average values. The results of monitoring of radiocaesium content in the main commercial fish species of the Azov Sea are presented for the same period. Comparison of caesium-137 content in the fish muscle tissues according to the sanitary and epidemiological regulations and standards, currently in force in the Russian Federation, is made. It is shown that the content of caesium-137 in the aquatic biological resources of the Azov Sea is much lower than the maximum permissible content of this isotope in fish and does not pose a radiation threat. For the investigated period, the state of the Azov Sea environment in terms of radiation does not give cause for concern pertaining to the accumulation of caesium-137 isotope. Radioecological monitoring of the Azov Sea area in 2017–2019 has revealed that Chernobyl trace remains the main source of radiation pollution.
    • Characterization of the allometric growth of soft-shell clam (Mya arenaria Linnaeus, 1758) in the Southern Azov Sea

      Zolotnitsky, A.P.; Sytnik, N.A.; Bragina, T.M. (2020)
      Allometric growth in the soft-shell clam, or sand gaper (Mya arenaria L.) population, inhabiting the Southern Azov Sea, is investigated. Quantitative characterization of relationship between the height (H, mm), depth (D, mm) and length (L, mm) of the shell of this mollusc, as it is based on the equations of linear (Y=a+b·X) and power (Y=a·Xb) functions, is presented. Shell shape parameters in the process of soft-shell clam growth, namely, elongation (H/L), and sagittal (D/L) and frontal (D/H) curvatures, have been studied. The relationship between mollusc length and its live body weight (W, g) is identified; it is approximated by a power function with the coefficient of proportionality (a) 1.64·10-4 and the coefficient of regression (b) 2.90. By means of the linear function, the new data on the relationship between shell weight (Wr), wet (Wm) and dry (Ws) weight of soft tissues, liquid held in the mollusc mantle (Wmj), siphon weight (Ws) and the total (live body) weight of soft-shell clam have been obtained. It is shown that several morphological characteristics of this species inhabiting the Azov Sea are similar in terms of their parameters to the ones of soft-shell clam populations in the White and Baltic Seas, although there exist certain distinctions.
    • Estimation of the meat yield of veined rapa whelk during its processing

      Esina, L.M.; Gorbenko, L.A.; Bragina, T.M. (2020)
      Technological standardization of the product yield after processing of aquatic bioresources is conducted to facilitate their rational management and the control over their exploitation; it also provides the means to plan out the product output and consumption of raw materials. At present, the standards for wastes, losses and meat yield are absent for the processing of a major fishing target in the Azov and Black Sea Fishery Basin, namely, veined rapa whelk Rapana venosa. In this article, the results of development and control work on standardization of wastes, losses and meat yield for veined rapa whelk, conducted in the processing environment and in the laboratory setting, are presented. The yield of veined rapa whelk meat was assessed as a proportion of the total weight of raw material incoming for processing. It is shown that the meat yield depends on the month when veined rapa whelk was harvested. The highest yield was recorded for May and June; in July and August, a decrease in the yield of veined rapa whelk meat was observed, which resulted from the growth of egg cases on the mollusc shell. For the individuals, on which shells egg cases are absent, or have been removed, a unified standard of meat yield for the entire course of harvesting season should be adopted. The meat yield for the individuals, which shells have not been cleaned of egg cases, is recommended to be regulated separately. A relation between meat yield and shell length has not been found. Statistical analysis of the data obtained on the yield of veined rapa whelk meat has shown their adherence to the law of Gaussian distribution.