Daily Increments Research Articles

Validation of otolith daily increment formation and early growth analysis of Japanese flounder (Paralichthys olivaceus)

The Japanese flounder is a vital economic species among East Asian released and cultured fish. Here, we sought to validate daily increment formation and analyze the early morphological development of sagittal otoliths and lapillus in Japanese flounder larvae and juveniles over 50 days. Our analysis focused on the otolith shapes, the number of daily rings present, and their length and width measurements. The results revealed that sagittal otoliths and lapillus formed before the fertilized eggs hatched. During the larval and juvenile stages, sagittae evolved gradually, transforming from nearly round to oval structures, eventually adopting arrow- or pear-shaped forms. Similarly, lapillus transformed from nearly round to mussel-shaped structures. The first daily ring became evident on the 5th-day post-hatching, demonstrating a daily periodicity during the larval phase. We observed a direct relationship between incubation days (D) and the number of daily otolith increments (n), expressed as D = n + 5. This deposition trend exhibited a daily periodicity for both sagittae and lapillus. We also noted exponential correlations between the length (Ls, μm) and width (Ws, μm) of the sagittae and the total length (TL, mm). Contrastingly, the lapillus measurements demonstrated linear correlations. Furthermore, a linear relationship emerged between the sagittae and lapillus lengths: Ll = 0.3028Ls + 28.534 (R2 = 0.9366). Additionally, we found a similar linear relationship between the sagittae and lapillus widths: Wl = 0.3791Ws + 21.508 (R2 = 0.9426). The formation pattern of daily increments in lapillus was notably more distinct than that in sagittae, making it highly suitable for age identification and group recognition. This study not only contributes to the field of fish ecology but also provides a foundational understanding for future research. It can assist in reconstructing early life histories and inferences about the spawning periods and grounds of stocked Japanese flounder.

Integrating data from cold-water coral habitats increase knowledge on age and growth studies: the case of Helicolenus dactylopterus (Delaroche, 1809) in the central Mediterranean

The aim of this study is to provide new insights on the age and growth of H. dactylopterus in the north-western Ionian Sea (central Mediterranean) by using different data sets and comparing three different methods, one direct by otolith reading corroborated by two indirect methods, by means of back calculation and Length Frequency Distribution analysis (LFDa), in order to obtain robust data for use in analytical management models. A total of 1403 specimens of blackbelly rosefish were sampled from habitats explored on muddy bottoms in the depth range 106-721 m and 309 individuals caught in the cold-water coral habitat between 418 and 635 m in depth. The length-frequency distributions of blackbelly rosefish showed a polymodal pattern in both habitats explored, with medium-small individuals caught on muddy bottoms and larger ones in coral habitats and canyons. The maximum age observed in females was 13 years (315 mm TL), while in males it was 15 years (336 mm TL), and no significant difference was observed comparing age-length keys from otolith readings of females with the males. The analysis of the daily increments allowed us to validate the average length of the first year of age (approximately 90-100 mm LT) obtained from the three different methods used. No significant difference was highlighted comparing the average lengths of age class 1, calculated with the direct method and by counting the daily increments. The von Bertalanffy growth parameters were estimated for the sexes and for the whole population from otolith readings and for the entire population by LFD analysis and the back calculation method. The growth curves were comparable between the different methods and no significant difference was observed. The von Bertalanffy growth parameters estimated for the different methods were comparable (otolith readings L∞ 494 mm, k=0.06 years-1, t0=-3.00 years; back calculation method L∞ 487 mm, k=0.06 years-1, t0=-2.30 years; LFDa L∞ 415 mm, k=0.07 years-1, t0=-2.23 years), indicating a slow growth in accordance with what has already been observed in other areas of the Mediterranean.

Enhancement of PV and concentered PV panels using evaporative cooling during summer and winter seasons: A case study in Egypt

Numerous efforts are made to comprehend the performance evolution of photovoltaic (PV) panels. The elevated surface temperature causes a deterioration in PV panels' performance, hindering the expected increase in harvested energy associated with integrating solar reflectors. In this context, the year-round efficacy of cooling PV panels supported by reflective mirrors is investigated to assess the effectiveness of solar reflector implementation. A conventional PV panel, a CPV (cooled PV panel), and a CCPV (concentrated cooled PV panel) were compared side-by-side to determine their relative performance and energy productivity. Evaporative cooling pads are utilized to chill the two modified PV systems by varying the coolant flow rate during the summer and winter seasons of 2022 and 2023, respectively, in the environmental conditions of the Tenth of Ramadan City, Egypt. The findings indicate that the average daily power increment ratio (PIR) for CPV ranges from 4.7 % up to 7.4 %, while CCPV ranges from 6.7 % to 12 % for different climate conditions year-round. Finally, changing the setup configuration from CPV to CCPV increased the (PIR) 1.5 times during the summer tests and 1.7 times during the winter tests.

Research and Application of Chemical Water Plugging Technology with High Salt Resistant Gel and Immobile String

Abstract The salinity of formation water in Gasi N1-N2 reservoir is 18 × 104 mg/L, in which calcium and magnesium ions are 6300 mg/L. The conventional gel used for profile control and water plugging has poor salt resistance and is easy to dehydrate under the erosion of formation water; At the same time, the chemical water plugging of oil wells in the past needs to trip down the downhole string for many times, and the construction period is long. In order to solve the former problem, an anti-high salt organic gel suitable for Gasi N1-N21 reservoir is synthesized. The formula is 0.4 wt% SD-3000 + 0.1-0.2 wt% urotropine + 0.05 wt% resorcinol + 0.4 wt% additive. The viscosity of the gel is more than 6000 mPa.s after gelation, and no obvious dehydration phenomenon is found after aging for five months in the formation water environment of Gasi N1-N21 reservoir at 65 °C. The technology of chemical water plugging without moving the string has been innovatively developed, which does not require the operation of tubing and pump during construction. In Gasi N1-N21 reservoir, anti-high salt gel was used to carry out three well-times of chemical water plugging tests without pulling the string, which were all successful, saving 44% of the cost of measures and shortening 78% of the construction period. After water plugging, water production was obviously inhibited, and the average moisture content was reduced from 95% to 45%. The average daily oil increment of a single well was 1.8 tons, and the cumulative oil increment was 1700 tons. The results show that the chemical water plugging technology without pulling string has broad application prospects in Gasi N1-N21 reservoir in Qinghai Oilfield and similar reservoirs in China.

Age Estimation in Sepia officinalis Using Beaks and Statoliths.

Establishing the age of cephalopods is crucial for understanding their life history, which can then be used for assessment and management. This is particularly true for the common cuttlefish Sepia officinalis (Linnaeus, 1758), one of the most important resources for coastal fisheries. For this reason, an age analysis of S. officinalis was performed for the first time in the Mediterranean, using beaks and statoliths from 158 wild specimens (55-222 mm mantle length; 23-1382 g total weight) at different maturity stages (immature to mature). Growth increments were counted in the lateral wall of the upper beaks and the lateral dome of statoliths. In both cases, a good relationship was found between the counts and the sizes of the animals. The low values of coefficients of variation between the readings obtained for beaks (3.96 ± 1.87%) and statoliths (4.00 ± 1.89%) showed a high level of precision and accuracy in the readings. However, the analysis was simpler for beaks, which were all successfully analyzed, while it was more complex for statoliths, with 69% being lost due to rejection or overgrinding. Based on daily increments previously validated in statoliths, the beaks were cross-verified by comparing their counts with those from statoliths extracted from the same 83 specimens, obtaining a statistically significant relationship between the two counts, confirmed by the ANOVA test. Absolute growth rates that were assessed using both beaks and statoliths indicated that the two sexes had a higher growth rate at 122 and 182 days, which subsequently declined in older specimens. Due to the relative simplicity of its processing method, the beak was finally proposed as a suitable hard structure to study the age of S. officinalis. We also confirmed the good readability of increments in the lateral wall of the beak, which could be considered a valid alternative to the rostrum surface.

Показатели крови перепелов при скармливании муки из высушенных личинок Lucilia Caesar

The aim of the research was to study the effect of compound feed with the addition of flour from dried larvae of the Lucilia Caesar fly on the morphological and biochemical parameters of the blood of young quails. The experiment was conducted on 160 Phoenix quail at the age of 10 days, of which two groups were formed according to the principle of balanced groups. The results of the tests showed that all the studied blood parameters of the experimental bird were within the physiological norm. When feeding compound feed with a protein supplement from flour of the Lucilia Caesar larva, the content of albumins in the blood serum of quails of the second group decreased by 2.0 g/l (p≤0.05)., globulins - by 1.0 g/l (p≤0.05), urea - by 0.24 mmol/l (p≤0.01). Probably, a decrease in albumins and urea in the blood of quails of the second group indicates that they are involved in protein synthesis. Gamma-glutamyltransferase (GGT) is an enzyme involved in amino acid metabolism. Catalyzes the transfer of a gamma - glutamyl residue from a gamma-glutamyl peptide to an amino acid, another peptide, or, during hydrolysis, to water. The activity of the enzyme in the blood increases in liver diseases. In our experiment, a decrease in the GGT content by 2.66 u/l in the blood of a bird receiving flour from the larvae of the Lucilia Caesar fly probably indicates an activation of amino acid synthesis in the body, which is quite consistent with the data of the average daily increments of the experimental bird. Lactate dehydrogenase (LDH) in the blood is an enzyme localized inside cells. The composition necessarily includes zinc ions. The main function is to catalyze the oxidation of lactic acid to pyruvate. In diseases accompanied by tissue damage and cell destruction, LDH activity in the blood increases. In this regard, it is an important marker of tissue destruction. According to our data, LDH levels in the blood of the experimental bird of the second group significantly decreased by 2909.75 mmol/l (p≤0.05), which indicates an improvement in the functional activity of the liver.

Hybridization Model for Air Pollution Prediction Using Time Series Data

In recent years, data science analysis, particularly time series predictions, has been widely employed across various industrial sectors. However, time series data presents high complexity, especially in seasonal patterns such as monthly, daily, or hourly fluctuations. Irregular fluctuations and external factors increasingly challenge accurate predictions. Therefore, this research proposes a hybrid approach combining SVR-SARIMA, SVR-Prophet, LSTM-SARIMA, and LSTM-Prophet to enhance time series prediction accuracy. This study followed the OSEMN methodology approach: gathering data, cleaning data, exploring data, developing models, and interpreting crucial aspects of problem-solving. Seasonal effect predictions indicated a rise in SO2 and NO2 during dry and rainy seasons until the next two years (average daily increments of 0.0831 μg/m3 for SO2 and 0.0516 μg/m3 for NO2). Estimates suggest a decrease in the order of three particles. The evaluation showed that the SVR model performed better compared to the other three models (RMSE 7.765, MAE 5.477, and MAPE 0.261). The best-performing hybrid model was LSTM-Prophet (99.74% accuracy) with RMSE 12.319, MAE 12.057, and MAPE 0.259 values.

Intra‐annual radial growth of Quercus acutissma and its response to hydrometeorological factors in the Nandadish experimental catchment, eastern China

AbstractInvestigating the relationship between tree growth within a year and environmental factors is crucial for understanding how climate change affects seasonal tree growth patterns. In this study, high‐resolution point dendrometers were used to monitor the stem radial changes of Oak trees (Quercus acutissma) over two years (2020 and 2021) in the eastern subtropical monsoon region of China. We find that the main growth period of Oak trees spans from March to September, and air temperature significantly affects the growth onset of Oak trees but with no clear impact on their growth cessation. The observations show that precipitation substantially affects daily stem radial increment (SRI), but the frequency of precipitation days plays a more crucial role in enhancing seasonal growth than the total precipitation amount. In the growing season, the stem radius of the Oak trees shows obvious diurnal cycles with shrinkage during the day and expansion at night, reflecting a delicate balance between canopy water loss and soil water absorption. The diurnal variations of the stem radius during the cold period (January and December) show an opposite pattern to that of the growing season, due to the sap's freezing under the condition of low air temperature at night as well as no or weak transpiration in the daytime. Because the temporal dynamics and intensity of tree activities significantly affect the timing and mechanisms of carbon assimilation in terrestrial ecosystems, our results are helpful to evaluate the carbon sequestration capacity of subtropical forests under the global climate change.

The effects of solar radiation on daily and seasonal stem increment of canopy trees in European temperate old-growth forests.

It is well established that solar irradiance greatly influences tree metabolism and growth through photosynthesis, but its effects acting through individual climate metrics have not yet been well quantified. Understanding these effects is crucial for assessing the impacts of climate change on forest ecosystems. To describe the effects of solar irradiance on tree growth, we installed 110 automatic dendrometers in two old-growth mountain forest reserves in Central Europe, performed detailed terrestrial and aerial laser scanning to obtain precise tree profiles, and used these to simulate the sum of solar irradiance received by each tree on a daily basis. Generalized linear mixed-effect models were applied to simulate the probability of growth and the growth intensity over seven growing seasons. Our results demonstrated various contrasting effects of solar irradiance on the growth of canopy trees. On the one hand, the highest daily growth rates corresponded with the highest solar irradiance potentials (i.e. the longest photoperiod). Intense solar irradiance significantly decreased tree growth, through an increase in the vapor pressure deficit. These effects were consistent for all species but had different magnitude. Tree growth is the most effective on long rainy/cloudy days with low solar irradiance.

Thioredoxin promotes the regeneration and binding of elastic fibre and basement membrane.

Thioredoxin (TRX), a ubiquitous protein with strong antioxidant activity, decreases in the skin with age. A decrease in TRX is expected to induce cellular senescence, chronic inflammation, and degeneration and loss of extracellular matrix (ECM), such as collagen and elastin within the skin. In this study, we investigated the effects of TRX addition to excised skin or skin models to understand the role of TRX on cells and ECM within the skin. To evaluate its effect on skin cells, we cultured a three-dimensional (3D) skin model in a medium containing TRX. The mRNA expression levels of proteins related to elastic and collagen fibres and the basement membrane were determined. Furthermore, 3D imaging and computational analysis were performed to evaluate the effect of TRX on the elastic fibres and extending COL VII structures in excised human skin after coculturing with TRX for 1, 4, 5 and 6 days. Thioredoxin application to a 3D skin model upregulated elastin, COLI and COLVII mRNA expression. Applying TRX to the excised skin increased the number of linear elastic fibres. This effect of TRX demonstrated a daily increment in a dose-dependent manner. Thioredoxin extended the fibrous structure of COL VII into the dermis, expanding its colocalization region with elastic fibres. These structural effects were confirmed using 3D imaging and computational methods. Thioredoxin elongates elastic fibres from the dermis to the basement membrane and extends the COL VII structure from the basement membrane to the dermis in excised human skin. These findings suggest the potential of TRX to protect the skin against age-related alterations such as wrinkles and sagging.

Automated extraction of Tridacna shell growth patterns via machine learning for enhanced paleoclimate/paleoweather research

Tridacna spp. are valuable archives for paleoclimate and paleoweather research due to their distinct daily growth patterns and the sensitivity of the daily growth patterns to environment changes. However, manually identifying daily growth lines and measuring the daily growth increment width (DGIW) of Tridacna shells from Laser Scanning Confocal Microscopy (LSCM) images is a tedious task that has become a significant barrier to Tridacna studies. This paper addresses this challenge by integrating machine learning into Tridacna research for the first time to automate the calculation of the number of daily growth lines and DGIW of Tridacna shells. Specifically, we propose an unsupervised generative adversarial attention network called TriGAN to automatically recognize distinct daily growth lines of Tridacna shells from LSCM images. Utilizing modern Tridacna specimens collected from the South China Sea, our experimental results demonstrate that TriGAN can effectively reconstruct the ambiguous and blurred regions in LSCM images and produce higher quality images of daily growth patterns compared to existing image generation networks. Furthermore, the daily growth line number and DGIW of Tridacna shells can be counted automatically from the images recognized by TriGAN, which are in good agreement with the statistical results obtained manually from the original LSCM images (R = 0.7, p < 0.01 for the DGIW profile of T. gigas specimen MD1 and R = 0.6, p < 0.01 for T. derasa specimen XB10). This automated method provides an efficient solution for researching the laminar chronology of Tridacna.

Alizarin Red S Marking in Otoliths: A Study on the Growth Dynamics of Diplodus vulgaris Juveniles

This study investigates the age and growth rates of juvenile Diplodus vulgaris in the Çanakkale Strait, utilizing Alizarin Red S (ARS) marking to analyze otoliths for daily growth increments. The research aimed to validate the daily deposition of growth rings in otoliths as a reliable method for age determination in young fish. A total of 65 specimens were subjected to ARS immersion at varying concentrations to identify the optimal marking conditions that would not adversely affect the survival rates of the juveniles. Post-treatment, the fish were released into controlled environments and monitored over a period to assess the incorporation and visibility of ARS marks in the otoliths. The results demonstrated a clear correlation between fish size and age, with a consistent daily growth rate that supports the hypothesis of daily increment formation in otoliths. The mortality rate associated with ARS treatment was within acceptable limits, confirming the method's viability for non-lethal age and growth studies. This research not only underscores the effectiveness of ARS marking in studying juvenile fish growth patterns but also contributes to a better understanding of the life history of D. vulgaris in the Çanakkale Strait, offering valuable insights for fisheries management and conservation efforts.

Validation of Daily Growth Increment Deposition in Sagittal Otoliths of the Young of the Year Lithognathus mormyrus

Validation of Daily Growth Increment Deposition in Sagittal Otoliths of the Young of the Year Lithognathus mormyrus

Python farming as a flexible and efficient form of agricultural food security

Diminishing natural resources and increasing climatic volatility are impacting agri-food systems, prompting the need for sustainable and resilient alternatives. Python farming is well established in Asia but has received little attention from mainstream agricultural scientists. We measured growth rates in two species of large pythons (Malayopython reticulatus and Python bivittatus) in farms in Thailand and Vietnam and conducted feeding experiments to examine production efficiencies. Pythons grew rapidly over a 12-month period, and females grew faster than males. Food intake and growth rates early in life were strong predictors of total lifetime growth, with daily mass increments ranging from 0.24 to 19.7 g/day for M. reticulatus and 0.24 to 42.6 g/day for P. bivittatus, depending on food intake. Pythons that fasted for up to 4.2 months lost an average of 0.004% of their body mass per day, and resumed rapid growth as soon as feeding recommenced. Mean food conversion rate for dressed carcasses was 4.1%, with useable products (dressed carcass, skin, fat, gall bladder) comprising 82% of the mass of live animals. In terms of food and protein conversion ratios, pythons outperform all mainstream agricultural species studied to date. The ability of fasting pythons to regulate metabolic processes and maintain body condition enhances food security in volatile environments, suggesting that python farming may offer a flexible and efficient response to global food insecurity.

Juvenile downstream migration patterns of an anadromous fish, allis shad (Alosa alosa), before and after the population collapse in the Gironde system, France.

Diadromous fish have exhibited a dramatic decline since the end of the 20th century. The allis shad (Alosa alosa) population in the Gironde-Garonne-Dordogne (GGD) system, once considered as a reference in Europe, remains low despite a fishing ban in 2008. One hypothesis to explain this decline is that the downstream migration and growth dynamics of young stages have changed due to environmental modifications in the rivers and estuary. We retrospectively analysed juvenile growth and migration patterns using otoliths from adults caught in the GGD system 30 years apart during their spawning migration, in 1987 and 2016. We coupled otolith daily growth increments and laser ablation inductively-coupled plasma mass spectrometry measurements of Sr:Ca, Ba:Ca, and Mn:Ca ratios along the longest growth axis from hatching to an age of 100 days (i.e., during the juvenile stage). A back-calculation allowed us to estimate the size of juveniles at the entrance into the brackish estuary. Based on the geochemistry data, we distinguished four different zones that juveniles encountered during their downstream migration: freshwater, fluvial estuary, brackish estuary, and lower estuary. We identified three migration patterns during the first 100 days of their life: (a) Individuals that reached the lower estuary zone, (b) individuals that reached the brackish estuary zone, and (c) individuals that reached the fluvial estuary zone. On average, juveniles from the 1987 subsample stayed slightly longer in freshwaterthan juveniles from the 2016 subsample. In addition, juveniles from the 2016 subsample entered the brackish estuary at a smaller size. This result suggests that juveniles from the 2016 subsample might have encountered more difficult conditions during their downstream migration, which we attribute to a longer exposure to the turbid maximum zone. This assumption is supported by the microchemical analyses of the otoliths, which suggests based on wider Mn:Ca peaks that juveniles in 2010s experienced a longer period of physiological stress during their downstream migration than juveniles in 1980s. Finally, juveniles from the 2016 subsample took longer than 100 days to exit the lower estuary than we would have expected from previous studies. Adding a new marker (i.e., Ba:Ca) helped us refine the interpretation of the downstream migration for each individual.

Apremilast in Erythema Nodosum Leprosum: A Case Series

Erythema nodosum leprosum (ENL) is an immune-mediated inflammatory reaction (antigen-antibody reaction involving complement) of leprosy. Available standard treatment in the form of steroids or thalidomide does not work in all ENL patients. Apremilast is an oral phosphodiesterase-4 inhibitor with potent immunomodulatory action. At present, apremilast is approved for chronic plaque psoriasis and psoriatic arthritis, however, not in ENL. The aim of this study was to assess the effectiveness of apremilast in chronic recalcitrant ENL. It was a case series, in which apremilast was started in 10 consecutive patients with recalcitrant ENL with 10 mg morning dose with a daily increment of 10 mg until day 6, when the recommended dose of 30 mg twice daily for adults is reached. Follow-up was done every 1 month till 6 months. Three patients showed good responses. The drug was well tolerated with few side effects. The most common adverse effect reported was headache (n = 5), followed by nausea (n = 4) and diarrhea (n = 4). Apremilast has lower cost and better safety profile compared to thalidomide and may be an option with limited effectiveness for ENL.

The influence of morphological parameters of incubation eggs on the growth and development of repair young

The purpose of the research was to analyze the influence of morphometric parameters of eggs on the quality of day-old chickens, as well as the growth and development of repair young. The shape index of eggs weighing up to 55 g varied from 0.581 to 0.814, in eggs weighing - from 55g to 65 g from 0.687 to 0.805 units. All the eggs under study, having an optimal weight (55-65 g) in terms of suitability for incubation, were divided into 3 groups depending on the size of the shape index: group 1 – 0.687-0.725; group 2 – 0.726-0.764; group 3 – 0.765-0.805. The live weight of day-old chickens in the first group ranged from 31.81 g to 35.47 g, with a coefficient of variation of 3.5%, and in the second, third and fourth groups from 37.12 g to 42.81 g with a coefficient of variation of 3.8%, 4.1% and 6.2%. The weight of day-old chickens of the second group was significantly higher than in the third and fourth groups by 1.4% and 1.2%, respectively. At the age of 17 weeks, the difference in the live weight of the repair young between the second, third and fourth groups was not significant and ranged from 0.14% to 0.38%, and in average daily increments from 0.05% to 1.16%. The repair young of the first group were significantly inferior to their peers in terms of live weight by 207.48-213.94 g, and in terms of average daily gains - by 15.5-14.5%. The safety of livestock was: group 1 - 89.6%; group 2 - 98.7%; 3 - 97.3; group 4 - 97.5%. The uniformity of poultry by live weight in the groups was 80.2-85.7%.

Staining protocols affect use of otolith to estimate the demography of the damselfish sergeant major (Abudefduf vaigiensis).

This study assessed the otolith (sagittae, lapilli, and asterisci) increment deposition rate in the range-shifting damselfish, A. vaigiensis, using different concentrations of Alizain Red S and evaluated the impact of staining on increment width. Daily increment deposition was verified in all otolith types and presented clearer fluorescent markings in the lapilli and sagittae than the asterisci, with high stain concentration showing the best clarity. Higher stain concentrations were found to decrease increment width, suggesting care is needed when using stained otoliths as a proxy for growth for this species.

Optimal growth and feeding behaviour of the valuable bait Halla parthenopeia (Polychaeta: Oenonidae) in small-scale rearing systems

Commercial farming of polychaetes used as baits in recreational fishing and feed supplements for aquaculture has been regrettably limited to a few species. The rearing conditions and diet that optimize the survival and growth remain largely unknown for most species. This study aimed at improving the current knowledge on the rearing of the large bivalve-feeder polychaete Halla parthenopeia, one of the most appreciated and expensive baits by Mediterranean fishermen. We set up a laboratory rearing system for H. parthenopeia to address several management procedures and solutions aimed at improving the rearing method that has been employed so far. We also provide a detailed reconstruction of feeding behaviour and prey preferences which were unknown for the Mediterranean populations. Finally, we assessed growth when fed on commercial, intact clams or artificially opened clams. The latter fed has been never tested in previous studies on Halla species and simulates commercial waste clams, a potential low-cost resource for polychaete maintenance. The setting up of a grow-out system based on single worms maintained in small PET containers on the bottom of recirculating aquaria permitted the non-stressful manipulation of H. parthenopeia and an easy management of the aquarium system. We observed that polychaetes consumed both C. gallina and R. philippinarum, showing a nocturnal foraging behaviour consisting in three phases: searching, handling, and feeding. The duration of handling + feeding period (1–4 h) depended on bivalve size. Offering intact R. philippinarum clam, a significant positive correlation between the predator and prey size occurred i.e. the smaller the predator, the smaller the prey-size selected, probably because less time and energy were required for handling. The same behaviour was observed also for the congeneric Halla okudai and in H. parthenopeia from the Suez Canal. Polychaetes preferred feeding on open clams than intact clams, independently from clam and worm size. An increase in the daily predation rate (up to 300%) and growth increment (up to 250%) was found for H. parthenopeia feeding on open clam, maybe for the lack of energetic cost for prey handling. These results suggest that an indoor small-scale production of H. parthenopeia fed with waste clams could meet the demand of the angling community and support further biotechnological applications of this polychaete.

Predicting potential spawning areas of European bass, Dicentrarchus labrax, in the Irish and Celtic seas

Marine fish species that form spawning aggregations are often vulnerable to exploitation, such as the European bass (Dicentrarchus labrax). Information on bass spawning aggregations is not well resolved temporally and spatially. Otolith daily growth increment (DGI) counts were conducted on 0-group bass collected in July-August 2014 & 2019 from seven settlement estuaries in the Irish and Celtic seas, to estimate the timing of spawning. These timings parameterised three-dimensional hydrodynamic and Lagrangian particle tracking models, run in reverse, to identify probable spawning locations. Estimated spawning occurred between April-May (inshore and offshore) < 200 km from each settlement area. At least two broad spawning areas were predicted: the central Irish Sea that led to post-larval recruitment in north Wales and northwest England, and the southern Irish Sea/Celtic Sea that led to post-larval recruitment in south Wales. Results indicate the current seasonal closure for northern stock bass may not protect spawning events that drive recruitment into settlement sites in Wales and northwest England. Surface temperatures and wind- and tide-driven surface currents determined the connectivity between spawning and settlement sites. Atmospheric drivers are expected to change in the future and management needs to account for potential regional shifts in spawning times and locations.