Seasonal bleaching and partial mortality of Pocillopora verrucosa corals of the coast of central Vietnam

IntroductionCoral reefs are one of the most productive yet vulnerable ecosystems on Earth. An important step in understanding the functioning of coral communities is studying the environmental impact on the state of reefs. The present study aimed to assess the impacts of the water temperature, precipitation, wave action, and population density on the seasonal bleaching, partial and complete mortality of shallow-water branching corals of Pocillopora verrucosa species complex. Materials and methodsThe present study was conducted at the Dam Bay research station (Nha Trang Bay) from 26 April 2020 to 2 April 2021. The environmental data was collected from the Dam Bay weather station and using a temperature logger planted on the nursery, coral bleaching and mortality were assessed visually using photos taken underwater. ResultsThroughout the study, the percentage of bleached coral colonies varied from 1 to 41.5% with two peaks, in autumn (October) and spring (April). Rates of the development of partial mortality varied from 0 to 10%, with a pronounced peak in December. At the end of the experiment, the percentage of coral colonies suffering from partial mortality reached 47%. Only 4,5% of experimental colonies died to the end of the study. Analysis revealed that water temperature and partial mortality are the drivers of bleaching, while wave action, temperature and bleaching are the factors with a significant impact on partial mortality.DiscussionThus, both bleaching and patrial mortality are interlinked and the effect of partial mortality on bleaching is stronger than the opposite. Both phenomena have pronounced seasonal variation, but their maximum manifestation does not coincide in time allowing corals to avoid their synergetic effect. Moreover, it was found that the impact of individual stress on mortality prevailed over the impact of seasonal bleaching and partial mortality events. The main cause of coral death was the development of algal fouling at the sites of colony lesions, which gradually spread over the entire surface of the colony

Метод виявлення малорозмірних повітряних об’єктів оглядовими радіолокаційними станціями

We proposed the introduction of an additional mode of dispersed reception and the combination of one-position and multiple reception of signals to the existing one-position observation radar. We improved the algorithm for detection of an air object at its irradiation by several transmitters. We provided compensation of a delay time and Doppler frequency in each receiving channel to a separate volume of an observation radar upgrading the algorithm. The improved algorithm for detection of an air object at its irradiation by several transmitters is reduced to: coherent processing of received signals in each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency; quadratic detection in each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency; weight summation of detector outputs for each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency.We constructed a structural diagram of the detector of an air object at its illumination by several transmitters. Each receiving channel of a signal is a multichannel for distance and speed. The diagram provides reception, coherent processing of echo signals from third-party sources, compensation of delay and Doppler frequency differences relative to a separate volume of the observation radar and incoherent weight summation.We carried out estimation of the efficiency of detection of an air object at its irradiation by several transmitters. We established that the transition from a single-channel detection of an air object to the detection of an air object at the incoherent combination of two channels results in a significant shift of detection characteristics to the left.We selected the number of receiving channels to be combined. We established that it is most effective to combine two, at most three, reception channels.We constructed a structural diagram of channels that process echo signals of an observation radar by combining the methods of one-position and differential signal reception. For combining of one-position and dispersed location modes of observation radars, we provided complexing of corresponding digital reception devices and digital signal processing systems. The main principle underlying the combination of the mentioned receiving devices is the informational supplement without violating the standard modes of operation of observation radar.Предложено введение в существующую однопозиционную обзорную РЛС дополнительного режима разнесенного приема и объединение однопозиционного и разнесенного приема сигналов. Усовершенствован алгоритм обнаружения малоразмерных воздушных объектов при его облучении несколькими передатчиками. Разработанная схема обнаружителя обеспечивает прием, согласованную обработку эхо-сигналов внешних источников, компенсацию разности в задержке и частоте Допплера относительно разрешающего объема обзорной РЛС и некогерентное весовое суммирование. Установлено, что наиболее эффективным является объединение двух, максимум трех каналов приемаЗапропоновано введення в існуючу однопозиційну оглядову РЛС додаткового режиму рознесенного прийому та об’єднання однопозиційного та рознесеного прийому сигналів. Удосконалено алгоритм виявлення повітряного об’єкта при його опроміненні декількома передавачами. Розроблена схема виявлювача забезпечує прийом, узгоджену обробку ехо-сигналів сторонніх джерел, компенсацію різниць в затримці та частоті Допплера відносно роздільного об'єму оглядової РЛС та некогерентне вагове підсумовування. Встановлено, що найбільш ефективним є об’єднання двох, максимум трьох каналів прийом

Метод виявлення малорозмірних повітряних об’єктів оглядовими радіолокаційними станціями

We proposed the introduction of an additional mode of dispersed reception and the combination of one-position and multiple reception of signals to the existing one-position observation radar. We improved the algorithm for detection of an air object at its irradiation by several transmitters. We provided compensation of a delay time and Doppler frequency in each receiving channel to a separate volume of an observation radar upgrading the algorithm. The improved algorithm for detection of an air object at its irradiation by several transmitters is reduced to: coherent processing of received signals in each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency; quadratic detection in each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency; weight summation of detector outputs for each processing channel in each element corresponding to the relevant separate volume and the relevant separate Doppler frequency.We constructed a structural diagram of the detector of an air object at its illumination by several transmitters. Each receiving channel of a signal is a multichannel for distance and speed. The diagram provides reception, coherent processing of echo signals from third-party sources, compensation of delay and Doppler frequency differences relative to a separate volume of the observation radar and incoherent weight summation.We carried out estimation of the efficiency of detection of an air object at its irradiation by several transmitters. We established that the transition from a single-channel detection of an air object to the detection of an air object at the incoherent combination of two channels results in a significant shift of detection characteristics to the left.We selected the number of receiving channels to be combined. We established that it is most effective to combine two, at most three, reception channels.We constructed a structural diagram of channels that process echo signals of an observation radar by combining the methods of one-position and differential signal reception. For combining of one-position and dispersed location modes of observation radars, we provided complexing of corresponding digital reception devices and digital signal processing systems. The main principle underlying the combination of the mentioned receiving devices is the informational supplement without violating the standard modes of operation of observation radar.Предложено введение в существующую однопозиционную обзорную РЛС дополнительного режима разнесенного приема и объединение однопозиционного и разнесенного приема сигналов. Усовершенствован алгоритм обнаружения малоразмерных воздушных объектов при его облучении несколькими передатчиками. Разработанная схема обнаружителя обеспечивает прием, согласованную обработку эхо-сигналов внешних источников, компенсацию разности в задержке и частоте Допплера относительно разрешающего объема обзорной РЛС и некогерентное весовое суммирование. Установлено, что наиболее эффективным является объединение двух, максимум трех каналов приемаЗапропоновано введення в існуючу однопозиційну оглядову РЛС додаткового режиму рознесенного прийому та об’єднання однопозиційного та рознесеного прийому сигналів. Удосконалено алгоритм виявлення повітряного об’єкта при його опроміненні декількома передавачами. Розроблена схема виявлювача забезпечує прийом, узгоджену обробку ехо-сигналів сторонніх джерел, компенсацію різниць в затримці та частоті Допплера відносно роздільного об'єму оглядової РЛС та некогерентне вагове підсумовування. Встановлено, що найбільш ефективним є об’єднання двох, максимум трьох каналів прийом

Counting stars: contribution of early career scientists to marine and fisheries sciences

Scientific careers and publishing have radically changed in recent decades creating an increasingly competitive environment for early career scientists (ECS). The lack of quantitative data available on ECS in marine and fisheries sciences prevents direct assessment of the consequences of increased competitiveness. We assessed the contributions of ECS (up to 6 years post first publication) to the field using an indirect approach by investigating the authorships of peer-reviewed articles. We analysed 118461 papers published by 184561 authors in the top 20 marine and fisheries sciences journals over the years 1991–2020. We identified a positive long-term trend in the proportion of scientific articles (co-)authored by ECS. This suggests a growing contribution by ECS to publications in the field. However, the mean proportion of ECS (co-)authors within one publication declined significantly over the study period. Subsequent tests demonstrated that articles with ECS (co-)authors receive fewer citations and that the proportion of ECS (co-)authors on an article has a significant negative effect on the number of citations. We discuss the potential causes of these inequalities and urge systematic support to ECS to achieve more balanced opportunities for funding and publishing between ECS and senior scientists

Spatial distribution of Cephalopods of the European Shelf and their associated oceanographic parameters based on occurrence in standardized demersal fishing trawls

Changing oceans impact the whole marine ecosystem in different ways. For example, rising ocean temperatures can affect the presence / absence of species, especially when local environmental conditions exceed individual species’ physiological tolerances. Accordingly, climate change has caused shifts in distribution and expansions for various cephalopods worldwide. Cephalopods play an important role in the ecosystem, especially in food webs. Consequently, spatial distribution shifts might help explain observed ecosystem changes. Therefore, maps for cephalopod distributions need to be reviewed and updated. Meanwhile, information on the associated environmental conditions will permit future occurrence of cephalopods to be modelled, which is interesting from a fishery and ecological perspective. Some information about physiological tolerances of cephalopods are known from laboratory studies and aquaculture experience, as well as from field observations. Laboratory data are often based on narrow ranges, depending on the experimental design, and can therefore provide only a limited understanding of physiological tolerances. On the other hand, field observations are also limited due to the spatial and temporal limitations of surveys, but these might provide a more realistic picture of natural tolerances. Here, we use the ICES Datras dataset to, first, describe the current distribution of cephalopods associated with the European shelf and, second, advance the knowledge regarding environmental ranges of the various species included in the analysis by combining occurrence data with in-situ oceanographic data. An additional literature review will provide information about the different environmental requirements of various life stages. The results allow us to increase the knowledge of physiological preferences of various cephalopod species within the North-East Atlantic Ocean. Finally, we will discuss and present potential future trends in cephalopod occurrence within the NE Atlantic. In order to further strengthen our knowledge of physiological tolerances of various cephalopod species more data on life history and life stages is needed to develop a more advanced mechanistic model.info:eu-repo/semantics/publishedVersio

Working group on cephalopod fisheries and life history (WGCEPH; outputs from 2019 meeting)

info:eu-repo/semantics/publishedVersio

The significance of cephalopod beaks as a research tool: An update

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960's, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed.info:eu-repo/semantics/publishedVersio

Working group on cephalopod fisheries and life history (Wgceph; outputs from 2022 meeting)

Rapports Scientifiques du CIEM. Volume 5, nº 1WGCEPH worked on six Terms of Reference. These involved reporting on the status of stocks; reviewing advances in stock identification, assessment for fisheries management and for the Ma- rine Strategy Framework Directive (MSFD), including some exploratory stock assessments; re- viewing impacts of human activities on cephalopods; developing identification guides and rec- ommendations for fishery data collection; describing the value chain and evaluating market driv- ers; and reviewing advances in research on environmental tolerance of cephalopods. ToR A is supported by an annual data call for fishery and survey data. During 2019–2021, com- pared to 1990–2020, cuttlefish remained the most important cephalopod group in terms of weight landed along the European North Atlantic coast, while loliginid squid overtook octopus as the second most important group. Short-finned squid remained the least important group in land- ings although their relative importance was almost double in 2019–2022 compared to 1992–2020. Total cephalopod landings have been fairly stable since 1992. Cuttlefish landings are towards the low end of the recent range, part of a general downward trend since 2004. Loliginid squid landings in 2019 were close to the maximum seen during the last 20 years but totals for 2020 and 2021 were lower. Annual ommastrephid squid landings are more variable than those of the other two groups and close to the maximum seen during 1992– 2021. Octopod landings have generally declined since 2002 but the amount landed in 2021 was higher than in the previous four years. Under ToR B we illustrate that the combination of genetic analysis and statolith shape analysis is a promising method to provide some stock structure information for L. forbsii. With the sum- mary of cephalopod assessments, we could illustrate that many cephalopod species could al- ready be included into the MSFD. We further provide material from two reviews in preparation, covering stock assessment methods and challenges faced for cephalopod fisheries management. Finally, we summarise trends in abundance indices, noting evidence of recent declines in cuttle- fish and some octopuses of the genus Eledone. Under ToR C, we describe progress on the reviews of (i) anthropogenic impacts on cephalopods and (ii) life history and ecology. In relation to life history, new information on Eledone cirrhosa from Portugal is included. Under ToR D we provide an update on identification guides, discuss best practice in fishery data collection in relation to maturity determination and sampling intensity for fishery monitoring. Among others, we recommend i) to include the sampling of cephalopods in any fishery that (a) targets cephalopods, (b) targets both cephalopods and demersal fishes or (c) takes cephalopods as an important bycatch, ii) Size-distribution sampling, iii) the use of standardized sampling pro- tocols, iv) an increased sampling effort in cephalopod. Work under ToR E on value chains and market drivers, in conjunction with the Cephs & Chefs INTERREG project, has resulted in two papers being submitted. Abstracts of these are in the report. Finally, progress under ToR F on environmental tolerance limits of cephalopods and climate en- velope models is discussed, noting the need to continue this work during the next cycle.info:eu-repo/semantics/publishedVersio

The significance of cephalopod beaks as a research tool: An update

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960’s, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed