AquaDocs
Not a member yet
36984 research outputs found
Sort by
Morphological variation and haplotype diversity of Halimeda macroloba and H. opuntia (Chlorophyta: Halimedaceae) from Southern Vietnam
No full textPlasticity in morphology is a common phenomenon of aquatic plants. Halimeda (Chlorophyta: Halimedaceae) is usually supersaturated with calcium carbonate and is found in tropical and subtropical regions. Among members of Halimeda, both species including Halimeda macroloba and H. opuntia, often occur in different habitats. Haplotype diversity and network of Halimeda were reported in the different sea and oceanic systems. However, there are no reports of the genetic diversity of Halimeda in Vietnamese waters. This present study carried out sample collections along the coast of Southern Viet Nam, including the coast sites, offshore islands, and Spratly (Truong Sa) islands. External morphological and anatomical characteristics of two dominant species, Halimeda macroloba and H. opuntia, were caparisoned. The genetic marker tufA was applied to find the haplotype diversity and network among Vietnamese and worldwide populations. The results showed that high morphology exists in both species. In contrast, the genetic variation in H. macroloba is very low, and H. opuntia tends to form a distinct group. We suggest that more samples of two species from other locations in Northern Vietnam be included.PublishedReferee
Зоопланктон озерной части Мингечeвирского водохранилища и его залива Ханабад (Азербайджан)
No full textThis paper presents the results of zooplankton studies, conducted in the lake part of the Mingachevir Reservoir and in the Khanabad Gulf (Azerbaijan) in 2021. The taxonomic composition of the zooplankton community has been investigated, and 25 species and one subspecies have been identified. It has been found that all of them are typical species for the inland freshwater bodies of Azerbaijan, occurring both in mixohaline (brackish) and fresh waters. Ecological and zoogeographical characterization of the identified species is given, as well as their saprobity, and the seasonal dynamics of the community development is presented. The core of the community in terms of abundance and biomass was formed by cladocerans and copepods. In the lake part of the reservoir, the highest abundance was recorded in March and the highest biomass was recorded in June. In the Khanabad Gulf, the highest values of abundance and biomass were recorded in June. The Khanabad Gulf was characterized by the highest zooplankton productivity.В работе приведены результаты исследований зоопланктона, проведенных в 2021 г. в озерной части Мингечевирского водохранилища и в заливе Ханабад (Азербайджан). Исследован таксономический состав сообщества зоопланктона, идентифицировано 25 видов и один подвид. Установлено, что все они являются характерными для фауны внутренних водоемов Азербайджана и встречаются как в миксогалинных (солоноватых), так и в пресных водах. Даны экологозоогеографическая характеристика и сапробность идентифицированных видов, приведена сезонная динамика развития сообщества. Основу численности и биомассы формировали ветвистоусые и веслоногие ракообразные. В озерной части водохранилища максимум численности отмечался в марте, а биомассы — в июне. В заливе Ханабад самые высокие значения численности и биомассы зарегистрированы в июне. Наибольшей продуктивностью зоопланктона характеризовался залив Ханабад.PublishedReferee
Estimation of population structure, growth and condition of Lates calcarifer (Bloch, 1790) in the Bay of Bengal
No full textThe current study illustrates the life-history traits; including length frequency distribution (LFD), length-weight and length-length relationship (LWR and LLR), condition factors (allometric, KA; Fulton’s, KF; relative condition, KR; relative weight, WR), and natural mortality (Mw) of Lates calcarifer from the Bay of Bengal, Bangladesh. A total of 103 individuals were randomly collected from January to December 2021 using traditional fishing gear including Koral net and gill net. For each individual, total length (TL), standard length (SL), and total body weight (BW) were measured with measuring scale to 0.1 cm and digital balance to 0.1 g precision, respectively. The TL size class 84.0 cm was a numerically dominant group in the population. The b value of LWR (TL vs. BW) indicated positive allometric growth (b=3.28) pattern in the Bay of Bengal. Likewise, the b value of LLR indicated also the same growth pattern. Among the four types of condition factors, KF is the best-suited tool for evaluating the well-being of L. calcarifer. Additionally, WR exhibited significant divergence from 100 (P< 0.0001), defining an imbalanced habitat. The calculated Mw was 0.23 year-1 for L. calcarifer. Therefore, these findings would be used in the future for the improved management of this species in the Bay of Bengal as well as for connecting ecosystems.PublishedReferee
"Protected" but exactly from what? An overview on environmental monitoring insights, upcoming conservation purposes and outreach priorities from recent field-based experiences aimed at the SCUBA diving sector.
No full textUN Decade of Ocean Sciences, Sustainable Development Goals (SDGs) and forthcoming conservation issues, a new global framework for biodiversity resulting from COP15 negotiations, public engagement sessions and much more, but which kind of goals are we really going to pursue? The latest initiatives, supported also by the Spanish National Agency in the framework of an Erasmus+ initiative, are part of the personally promoted project “FINS INTO THE WATER OCEAN LITERACY INTO PRACTICE”. At first this initiative has been set on a voluntary basis, subsequently, the engagement of other partners at national level and across Europe, sharing some working goals also within the EMSEA Med regional working group and with some of the leading representatives of SCUBA diving sector (teaching agencies and private sector professionals), made possible the development of teaching resources in order to significantly contribute to the aforementioned gap filling. Despite some formal hostilities occurred over the years from institutional representatives toward some field-engaged professionals, there is a great willingness among these people to be actively engaged in conservation goals concerning their daily working environment. This contribution is a tangible proof of this shared attitude and highlights the need to address properly conceived multidisciplinary educational sessions [1;2;3;4;5]. According to FAIR data principles all the observations and field data obtained so far will be publicly shared within the next few months even on other digital platforms, in order to contribute to the baseline research and ameliorate the upcoming steps necessary to successfully fulfill marine conservation and coastal management duties.PublishedNot Know
Scientific, Technical and Economic Committee for Fisheries (STECF) – Stock Assessments: demersal stocks in Adriatic, Ionian and Aegean Seas and straits of Sicily (STECF-22-16).
No full textCommission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report documents the outcomes of STECF Expert Working Group 22-16: 2022 stock assessments of demersal stocks in the Adtiat ic, Ionian and Aegean Seas from the meeting held in Rome from 17th to 23th October 2022. A total of 16 fish stocks were considered and 15 were fully evaluated. The EWG reports age based assessments, target Fs, with short term forecasts for 9 stocks of the remaining 6 stocks, four of these do not have short term forecasts as he assessments are not suitable, and one is given ICES category 3 advice. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 based advice for those without assessments. The report contains the full stock assessment reports for the 14 assessments, the exploration of assessments and category 3 evaluations for the remaining stock. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2022.European UnionPublishedReferee
Population Parameters of Shortfin scad Decapterus macrosoma (Bleeker, 1851) in Antique, Philippines
No full textGrowth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off Antique province, Philippines, were investigated based on the length-frequency data collected from April 2019 until March 2020. Using the FISAT-II software, D. macrosoma growth parameters were computed as follows: L∞ = 26.18 cm TL, K = 1.00 yr-1, ø' = 2.836 yr-1, and an estimated life span of 3 years. Mortality values were estimated as: total mortality (Z) = 4.66 yr-1; natural mortality (M) = 1.88 yr-1; and fishing mortality (F) = 2.78 yr-1. The exploitation rate (E) was computed as 0.60 while Emax was 0.42 yr-1. The length at first capture Lc/L50 was estimated at 11.96 cm TL. There were two recruitment events in one year: July and December. D. macrosoma in Antique was growing isometrically and in good condition with the relative condition factor (Kn) values ranging from 0.99 to 3.39. The computed exploitation rate suggested that D. macrosoma faces a high level of exploitation in Antique waters. These results offer valuable information on the utilization, conservation, and management of D. macrosoma in the East Sulu Sea area.PublishedReferee
Population parameters of opportunistic fish from the upper Paraná River floodplain : influences of the El Niño-Southern Ocillation – ENSO.
No full textThe occurrences of El Niño - Southern Oscillation – ENSO climate events promote alterations in the global hydrological cycle, so that the precipitation pattern results in periods of extreme drought and floods in certain continental regions. The irregularity of rainfall inconstantly changes the hydrometric level of aquatic bodies, the flood pulse and the river discharge, which in turn alter the limnological variables, the primary productivity and the availability of resources and habitat for the aquatic organisms, possibly affecting their growth and reproduction patterns. Therefore, the population parameters (such as sex ratio, size at first sexual maturity, weight-length ratio and somatic growth) of the short-lived icthyofauna (CVC) in the upper Paraná River floodplain (PIARP) were evaluated and compared in different climate periods (El Niño, La Niña and Neutral) through statistical modeling, under Bayesian perspective. The population parameters were estimated for the Hyphessobrycon eques species, for it was one of the selected species that presented traits of opportunistic strategy, being so characterized as a short life cycle species. The results found partially corroborated with the predictions, that the highest sex ratio found was for the La Niña period (2.7 females for one male), followed by Neutral (2.3) and El Niño (1.3) periods. For the first maturity sizes (L50), estimated for both sexes, they were smaller in the La Niña period (23.87mm for females and 23.35mm for males), followed by the El Niño period (25.89 mm for females and 28.75mm for males) and Neutral period (25.97mm females/ 29.92mm males). The weight-length ratio showed that the male body shape (α) had a slightly higher body biomass (α) average than females in the Neutral and La Niña periods. However, in the El Niño period, the opposite of the other periods was observed. The estimated parameters for the female body shape (α) were higher in Neutral, followed, respectively, by the El Niño and La Niña period, though, for males, the body shape (α) was higher in Neutral, followed by the La Niña and El Niño period. The estimated median lengths for the ages are moderately longer in males than females. Furthermore, the estimated median lengths are relatively longer in extreme periods (La Niña and El Niño) for the initial ages (3 and 6 months) when compared to the Neutral period, both for males or females. For females, the estimated median lengths are comparably longer in the El Niño period than in the La Niña period, while the opposite is observed for males. For that reason, the reproductive tactics of H. eques presented in the La Niña period can be a population level’s response, used for the optimization of the reproductive success and for the maintenance of the species in the environment.As ocorrências dos eventos climáticos El Niño-Southern Ocillation – ENSO promovem alterações no ciclo hidrológico global, de forma que o padrão de precipitação resulte em períodos de seca e cheia extremos em determinadas regiões continentais. Essa irregularidade das chuvas altera o nível hidrométrico dos corpos aquáticos, pulso de inundação e descarga fluvial de forma não previsível, que por sua vez altera as variáveis limnológicas, produtividade primária, a disponibilidade de recursos e habitat para os organismos aquáticos, podendo afetar seus padrões de crescimento e reprodução. Desta forma, avaliou-se e comparou-se os parâmetros populacionais (como razão sexual, tamanho de primeira maturação, relação peso-comprimento e crescimento somático) da ictiofauna de ciclo de vida curto (CVC) nos diferentes períodos climáticos (El Niño, La Niña e Neutro) na planície de inundação do alto rio Paraná (PIARP) por meio de modelagem estatística, sob a perspectiva Bayesiana. Estimou-se os parâmetros populacionais para a espécie Hyphessobrycon eques, de estratégia oportunista, caracterizando como uma espécie de ciclo de vida curto. Os resultados indicaram a maior razão sexual encontrada para o período de La Niña (2,7 fêmeas para um macho), seguidos dos períodos Neutro (2,3) e El Niño (1,3). Para os tamanhos de primeira maturação (L50), estimados para ambos os sexos, foram menores nos períodos de La Niña (23,87mm para fêmeas e 23,35mm para machos), seguido dos períodos de El Niño (25,89mm para fêmeas e 28,75mm para machos) e Neutro (25,97mm para fêmeas e 29,92mm para machos). A relação peso-comprimento demonstrou que forma do corpo (α) dos machos apresentaram uma média de biomassa corporal (α) ligeiramente maior do que as fêmeas nos períodos Neutro e de La Niña. Todavia, no período de El Niño foi observado o contrário dos outros períodos. Os parâmetros estimados para a forma do corpo (α) da fêmea foi maior no Neutro, seguido do período de El Niño e La Niña. Enquanto para os machos a forma do corpo (α) foi maior no Neutro, seguido do período de La Niña e El Niño. Os comprimentos medianos estimados para as idades são ligeiramente maiores nos machos do que os comprimentos medianos esperados para as fêmeas. Ademais, os comprimentos medianos estimados são relativamente maiores nos períodos extremos (La Niña e El Niño, respectivamente) para as idades iniciais (3 e 6 meses) em relação ao período Neutro, tanto para os machos quanto para as fêmeas. Para as fêmeas, os comprimentos medianos estimados são relativamente maiores no período de El Niño do que no período de La Niña, enquanto para os machos, o inverso é observado. Desta forma, as táticas reprodutivas de H. eques apresentadas nos períodos de La Niña, podem ser uma resposta a nível de população, utilizada na otimização do sucesso reprodutivo e na manutenção da espécie no ambiente.Master
Alteration in nutrient concentration caused by P. ambrosettii affects relationship between invasive macrophyte H. verticillata and native E. najas: an experimental approach.
No full textNon native species can negatively affect the invaded environment. Often, these species have biological characteristics that benefit other non natives and facilitate their invasion, so knowing the facilitation mechanisms between invaders are useful to mitigate their damage to the ecosystem. Thus, in this study we tested the hypothesis that Pterygoplichthys ambrosettii, a non native catfish, has habits that can alter nutrient concentrations (phosphorus and nitrogen) in the water column, and positively affect the growth of an invasive macrophyte species in detriment of a native one, characterizing ecological facilitation among invasive species. Therefore, an experiment was conducted with six treatments and four replicas, using the invasive macrophyte Hydrilla verticillata and the native Egeria najas, in the presence and absence of P. ambrosettii, all with occurrence recorded in the upper Paraná River floodplain. The results showed that the treatments with P. ambrosettii had a lower amount of dissolved oxygen, higher electrical conductivity, higher concentration of chlorophyll-a, total phosphorus (TP) and inorganic nitrogen (NI). Macrophyte biomass was significantly higher in monoculture treatments with fish, with this effect being more intense for H. verticillata. When in the same treatment, in the absence of P. ambrosettii, H. verticillata showed greater biomass than E. najas, but with the fish presence, the macrophyte species did not differ in their biomass, indicating that the high concentration of nutrients makes the coexistence of these macrophytes possible. The results found will be useful for future actions to manage invasive species, especially in habitats where they co-occur.Espécies invasoras podem impactar negativamente o ambiente invadido. Frequentemente, estas espécies possuem características biológicas que beneficiam outras não nativas e facilitam sua invasão, portanto conhecer os mecanismos de facilitação entre invasoras é essencial para mitigar os danos ao ecossistema. Desta forma, neste estudo testamos a hipótese de que Pterygoplichthys ambrosettii, um cascudo invasor, com hábitos que podem alterar as concentrações de nutrientes (fósforo e nitrogênio) na coluna d'água, afeta positivamente o crescimento de uma espécie de macrófita invasora em detrimento de uma nativa, caracterizando a facilitação ecológica entre espécies invasoras. Para isso um experimento foi conduzido, utilizando a macrófita invasora Hydrilla verticillata e a nativa Egeria najas, na presença e ausência de P. ambrosettii (bem como ambas coocorrendo na presença e ausência do peixe), todos com ocorrência registrada na planície de inundação do alto rio Paraná. Os tratamentos com P. ambrosettii apresentaram menor quantidade de oxigênio dissolvido, maiores valores para a condutividade elétrica, clorofila-a, fósforo total (TP) e nitrogênio inorgânico (NI). A biomassa das macrófitas foi significativamente maior nos tratamentos de monocultura com peixe, sendo este efeito mais intenso para H. verticillata. Quando juntas na ausência de P ambrosettii, H. verticillata apresentou maior biomassa que E. najas, mas com a presença do peixe, as espécies não diferiram em sua biomassa, sugerindo que a alta concentração de nutrientes torna possível a coexistência das macrófitas. Os resultados encontrados se mostram úteis para o conhecimento da biologia destas espécies invasoras, assim como para futuras ações de manejo em pequenos habitats onde estas coocorrem.Master
Molluscans species diversity and protein expression analysis in Lunella coronate spp of family Turbinidae from the Manora Channel Karachi, Pakistan.
No full textManora rocky shore characterize as a shore having moderate to strong wave exposure, zonation pattern characterize by intertidal habit, different communities of invertebrates and algae bands dominated by molluscan diversity and associated fauna. The current study contribute the species diversity of molluscs from the Manora rocky ledge, coast of Pakistan. A total of 11 species were recorded pertaining to 9 families and 11 genera including family Turbinidae: Turbo bruneus, Lunella coronata, family Cerithiidae: Cerithium caeruleum, family Babyloniidae: Babylonia spirata, family Neritidae: Nerita albicilla, family: Chilodontaidae Euchelus asper, family Veneridae: Circenita callipyga, family Arcidae: Barbatia obliquata. Family Pectinidae, Mimachlamys townsendi, family Chamidae: Chama sp, family Littorinidae and Sub family Trachycardiinae V. assimile. In addition, Protein expression analysis of L. cornata was also observed through Polyacrylamide gel electrophoretic. L. coronata was previously reported from the coastal water of Pakistan with some morphological variation in the shell shape and the results reveled that electrophoretic patterns of proteins in L. cornata spp 1 and L. cornata spp2 differentiate from each as seen in morphological characters.PublishedReferee
Benthic assemblages for ecological evaluation of Lake Borollus, Mediterranean Sea, Egypt.
No full textLake Borollus is one of the largest and oldest Egyptian lakes, whereas it is located in the far north of the Delta and mediates between the two branches of Rosetta and Damietta. It is connected to the Mediterranean Sea through Boghaz El Borollus and to the Nile through the Bermbal Canal, which was established in 1926 to feed the lake with abundant quantities of Nile water and Nile fish. Central coordinates: latitude 31°30' N and longitude 30°49' E with an area has decreased from 160,000 acres to 108,000 acres. The present work provides an ecological study on the regional and temporal distribution of benthic communities in particular along the wetlands lakes waters. Indicated that, the effective sediment and water variables which significantly correlated with the distribution and abundance of the identified benthos assemblages of vegetation and animal’s groups include sediments structure, water quality (pH, S%, DO, BOD, temperature. Overall, 10 taxa and 27 species of macroinvertebrates were identified. They were exclusively associated with submerged vascular plants Potamogeton pectinatus while only 10 were alive forms and the rest were represented by calcareous shells of molluscs. The benthic flora and fauna were estimated in the Lake Botollus, Egypt is subjected to the influx of sewage effluents, agriculture drainages and industrial wastes. Also considerable amounts of drain water are constantly discharged along the southern drains. Quantitative hauls were performed at the different habitats during winter and summer, 2017 covering 12 sampling sites and 9 drains discharged directly to the lake which bottom sampling was collected by grab sampler were selected to represent the covering the different environments. The dredged area per each station was 225 cm2 per haul. Results illustrated that the distribution of benthos in the estimated area is greatly affected by the degree of pollution as well as the prevailing hydrological conditions. The aquatic submerged vascular plants Potamogeton pectinatus appeared as the most common species in the lake in addition the bottom animals appeared more- sensitive to pollution than submerged vascular; thus, their lowest counts were recorded at the most sites and the fauna was mainly represented by the Nematoda, Oligochaeta, Polychaeta, Insects larvae, Ostracoda, Amphipoda, Barnacles, and juvenile larvae of Mollusca. Sediments in some areas consist of organic materials (sludge) is composed of waste sewage and agricultural and industrial and others of sandy silt (silt), calcareous shells are mainly of molluscs’ and therefore it can determine some environments prevailing in the lake. Results indicated for examining configuration qualitative benthic macro during the study period were recorded 27 species, including 9 species of living benthic macro organisms include one type of aquatic submerged vascular plants of species Potamogeton pectinatus. Although higher values of taxonomic richness, the Shannon and index (H`) and evenness (J`) were obtained with the water Potamogeton pectinatus habitat as well as Ostracoda Sclerochilus contortus were most abundant.PublishedReferee