Comparative study of gonadal development of Ruditapes philippinarum (Adams and Reeve) and Ruditapes decussatus (L.) (Mollusca: Bivalvia): Influence of temperature

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14ºC the reproductive behaviour was similar, both species needing over 2 months to mature. At 18ºC, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias.Se llevaron a cabo experiencias de laboratorio para estudiar la influencia de la temperatura en el comportamiento reproductivo de dos especies de almeja, R. philippinarum y R. decussatus, en su adaptación a las condiciones térmicas en las costas de Galicia. En ambas especies la tasa de desarrollo gonadal está directamente relacionada con el incremento de temperatura. A 14ºC el comportamiento reproductivo es similar y ambas especies necesitan cerca de 2 meses para madurar. A 18ºC, la tasa de desarrollo gonadal de R. philippinarum es mayor que en R. decussatus. No obstante, los resultados de este estudio confirman que ambas especies se han adaptado perfectamente a las condiciones térmicas de las rías de Galicia, si bien, se detectan ciertas diferencias en su comportamiento reproductivo. Así, mientras R. philippinarum acumula ovocitos antes de su emisión parcial o total, en el caso e R. decussatus los gametos se liberan continuamente. En las primeras fases de su desarrollo, el aspecto de la gónada de R. philippinarum es muy heterogéneo, presentándose hasta 3 estados reproductivos simultáneamente, mientras que en R. decussatus el desarrollo gonadal es bastante más uniforme. Otra diferencia concierne al fenómeno de la reabsorción, común en R. philippinarum, pero muy raro en R. decussatus. Estas características pueden sustentar una mayor actividad reproductiva en R. philippinarum comparado con R. decussatus, y un mayor periodo reproductivo en el caso de la primera. Ello puede también representar una cierta ventaje adaptativa, de la especie foráneas (R. philippinarum) frente la especie nativa (R. decussatus), a las condiciones térmicas de las rías de Galicia

Comparative study of gonadal development of Ruditapes philippinarum (Adams and Revé) and Ruditapes decussatus (L.) (Mollusca, Bivalvia): Influence of temperature

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14°C the reproductive behaviour was similar, both species needing over 2 months to mature. At 18°C, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias

Energy balance of mussels Mytilus galloprovincialis: the effect of length and age

Clearance and ingestion rates, absorption efficiencies and respiration rates were measured in mussels Mytilus galloprovincialis Lmk of different lengths (53 to 89 mm) and age (10 to 24 mo) from cultivation rafts in the Ría de Arosa (Galicia, Spain). The experiments were carried out either in the laboratory, using monoalgal food (Isochrysis galbana) with an organic content of 91%, or under natural conditions of food availability in cultivation rafts with seston, the organic content of which ranged from 33 to 69%. Food concentrations ranged from 0.57 to 1.00 mg l-1 of total particulate matter (TPM), a load which is below the threshold for the production of pseudofaeces in Mytilus. These experiments proved that the ingestion rate (IR = mg TPM h-1) of food increases with the size of the mussel (measured as g of soft-tissue dry weight [DW]) according to the power equation IR = 12.661DW0.619, this model accounting for over 90% of the variance of the IR. Behavioural patterns that tended to maintain constant IR regardless of the density of the food were observed. Absorption efficiency (AE) is positively related to the organic content (OC) of the food according to the following hyperbolic equation: AE = 1.015 - 0.163(1/OC) (r = 0.940). AE is independent of mussel size for most of the size range used in this study, but there is a critical length around 85 mm, above which there is a noticeable decrease of AE. Metabolic expenditure, measured in terms of oxygen consumption standarized per unit of dry weight of flesh, tends to increase with the age of the mussel. The results obtained led to the conclusion that physiological traits such as the regulation of ingestion or differences in AE between groups do not explain the differences in growth between mussels of the same age. These differences must therefore be due to the limited food and space available as a result of the large numbers of mussels on the cultivation rafts and the agglomeration of mussels on the cultivation ropes.Versión de editor

Dynamics of biochemical components, lipids classes and energy values on gonadal development of R.philippinarum associated with the temperature and ingestion rate

This study evaluates the effect of temperature, coupled with ingestion rate, on the dynamics of biochemical components and lipid classes in R. philippinarum. The data are discussed with regard to sexual development and energy balance. Experimental protocol developed in the present study used two groups of the clam R. philippinarum: L (temperatures of 14 °C and 18 °C) and H (temperatures of 18 °C and 22 °C). The intra-group ingestion level was similar, although the ingestion level of the clams in the group H was 2.4 times higher than group L. We observed that R. philippinarum conditioned at 18 °C (18L) shows higher protein content, furthermore an important loss of organic weight was observed after 48 days. In such a situation, the clams use their own reserves (carbohydrates and glycogen) for sexual development while in situations without food stress (positive energy balance) and low temperature (14 °C) an accumulation of reserves is produced. Strikingly dissimilar behaviour in biochemical composition was observed for the 18H and 22H treatments, both with a positive energy balance. Despite similar protein content, the highest levels of carbohydrates were observed at the lower temperature (18 °C). Glycogen was also higher for the 18 °C treatment, although the differences were significant only in the males. Although the total lipids in R. philippinarum showed no significant differences in any treatment, they became apparent and related to sex when considering the individual lipid classes. There was no variation in lipid classes in the males between the 14L and 22H treatments despite the large disparity in the degree of sexual development. However, in the females significant differences in lipid classes (phospholipids, triglycerides) were observed. The results of this study show that a positive energy balance permits R. philippinarum gonadal development and accumulation of reserves both in low and high temperature conditions. In low temperature situations, gonadal development is slower and the energy reserves are accumulated in the form of carbohydrates. When the clams are conditioned at high temperatures, gonadal development is fast and complete, carbohydrates are consumed and lipids are accumulated.Publicado

Effects of food rations on gonadal development of the clam Ruditapes decussatus (L., 1758)

Influence of food availability on gonadal development of the clam Ruditapes decussatus (L., 1758) was studied. The clams were exposed to three rations (0.1 %, 0.05 % and 0.026 % of the microalgae Isochrysis galbana clone T-ISO) which, respectively, determined situations of positive, null, and negative energetic balances. The degree of sexual maturity was assessed by studying two nonspecific measurements, the dry weight of flesh variable and the condition index parameter, and two measurements specifically referring to the gonada tissue, gonadal occupation index and oocyte maximum diameter. Individuals reached sexual maturity on all of the rations, although both the rate at which the gametogenic development occurred and the volume of gonad generated were strongly influenced by food availability.Se estudió la influencia de la disponibilidad del alimento sobre el desarrollo gonadal de Ruditapes decussatus (L., 1758), para lo que se experimentaron distintas raciones de alimento de la microalga Isochrysis galbana clone T-ISO: 0,1 %, 0,05 % y 0,025 %, que determinaron situaciones de balance energético positivo, cero y negativo, respectivamente. El grado de madurez sexual se evaluó estudiando dos cuantificadores no específicos: el índice de condición y la variable peso seco de la carne; y otros dos cuantificadores referidos expresamente al tejido gonadal: el índice de ocupación gonadal y el diámetro máximo de ovocitos. Con todas las raciones se alcanzó la maduración sexual, si bien la velocidad con que se produjo el desarrollo gametogénico, así como la cantidad de gónada generada, estuvieron condicionadas por la disponibilidad alimenticia.Instituto Español de Oceanografí

Analyzing Key Performance Indicators for Mobility Logistics in Smart and Sustainable Cities: A Case Study Centered on Barcelona

[EN] Background: This article identifies and examines key performance indicators (KPIs) related to citizen mobility logistics in smart and sustainable urban areas. It begins with a comprehensive literature review to identify essential KPIs, offering valuable insights for both public and private stakeholders, including policymakers and mobility service providers. Drawing from various mobility projects in smart cities, the study extracts common KPIs and best practices. The focus of the paper then turns to Barcelona, Spain, where KPIs that matter most are analyzed. Methods: Using open data from the city council spanning from 2017 onwards, the study provides insights into the evolving mobility logistics landscape. KPIs from other European cities are also considered by utilizing similar open data sources. This comparative analysis provides valuable benchmarks and reveals disparities in mobility logistics. Throughout this investigation, the paper emphasizes the role of data quality in KPI selection. Results: Reliable open data significantly influence indicator choices and present challenges when comparing cities. Remarkably, the findings consistently highlight environmental data as an area requiring attention in sustainable mobility logistics. Conclusions: This paper makes contributions by identifying and examining KPIs relevant to citizen mobility logistics in smart and sustainable urban areas. It offers insights by applying these KPIs to Barcelona and conducting comparative analyses with other European cities. These findings serve as a valuable resource for policymakers, city planners, and mobility experts.This work was partially funded by the European Commission project UP2030 (HORIZONMISS-2021-CIT-02-01-101096405), the Alcoi¿s City Council (Catedra Alcoi Smart City), and the Spanish Ministry of Science and Innovation (PID2022-138860NB-I00 and RED2022-134703-T).Soriano-González, R.; Pérez Bernabeu, E.; Ahsini, Y.; Carracedo-Garnateo, P.; Camacho-García, A.; Juan-Pérez, ÁA. (2023). Analyzing Key Performance Indicators for Mobility Logistics in Smart and Sustainable Cities: A Case Study Centered on Barcelona. Logistics. 7(4). https://doi.org/10.3390/logistics70400757

Recent developments in financing and bank lending to the non-financial private sector: first half of 2021

Artículo de revistaFinancing conditions for households and firms remained accommodating in the first half of 2021. Improved macroeconomic expectations from the second quarter of the year have allowed credit standards to cease tightening, at the same time as demand for loans has picked up, particularly among households. This has contributed to an increase in the flow of loans as compared with end-2020, especially loans for house purchase. However, up to May (latest available figure) this growth in new financing has not translated into an acceleration of total outstanding household and corporate debt. In the sectors hardest hit by the pandemic, total outstanding bank lending to firms and sole proprietors grew moderately in the initial months of 2021. However, the cumulative growth since the onset of the pandemic has been sizeable as a result of the hefty liquidity needs in 2020, which were covered through increased debt. The significant adverse impact of the COVID-19 pandemic on economic activity is yet to be reflected in a broad-based increase in non-performing loans on deposit institutions’ balance sheets. However, Stage 2 credit remained on a rising trajectory in 2021 Q1, with loans to the hardest-hit sectors of economic activity accounting for the lion’s share. Non-performing loans also grew in these sectors, albeit by a lesser amount

Impact of size and food concentration on clearance and ingestion rates in the clam Ruditapes decussates (Linnaeus, 1758)

The impact of food concentration (C) and water flow on the clearance (TA) and ingestion (TI) rates of the clam Ruditapes decussates (Linnaeus, 1758) was studied, using different-sized specimens. We found no relationship between C and TA, whereas there was a significant relationship between C and TI (TI = 24.757 + 0.576 C). The relationship between TA and the clams' live weight (PV) was also significant (TA = 4.292 PV0.683). A close relationship between PV and TI was found only when food availability (AD), a parameter that includes food concentration and flow, was constant. When it was not, the equation TI = 64.089 + 0.015 PV + 0.546 AD appears to explain 96.1% of TI variability.Se estudia el efecto de la concentración de alimento (C) y el flujo sobre las tasas de aclaramiento (TA) e ingestión (TI) de Ruditapes decussatus (Linnaeus, 1758) con ejemplares de diferentes tamaños. En esta especie no se observa relación entre C y TA, mientras que entre TI y C la relación es significativa: TI = 24,757 + 0,576 C. Igualmente es significativa la relación entre TA y el peso vivo (PV): TA = 4,292 PV0,683. PV y TI guardan una estrecha relación sólo en caso de que el alimento disponible (AD), variable que engloba la concentración de alimento y el flujo, se mantenga constante. En caso contrario, se propone la utilización de la ecuación TI = 64,089 + 0,015 PV + 0,546 AD que explica el 96,1 % de la variabilidad de TI.Instituto Español de OceanografíaVersión de editor

Productive response of lambs fed Crescentia alata and Guazuma ulmifolia fruits in a tropical region of Mexico

polyethylene glycol (PEG) of the fruits of Crescentia alata and Guazuma ulmifolia was evaluated, the degradation kinetics of lamb diets with added fruit of the tree was determined, and the ration intake and growth rate of lambs fed these diets were measured. Twenty-five entire male lambs of 23.5± 0.44 kg body weight were used and distributed in treatments: T0 (control without fruit); T1 and T2, 15 and 30 % of the fruit of C. alata; and T3 and T4, 15 and 30 % of the fruit of G. ulmifoli

Energy balance of the clam Ruditapes decussatus (Linnaeus, 1758)

The effect of food ingestion and clam size on absorption efficiency, absorption rate and oxygen consumption of the clam Ruditapes decussatus (L., 1758) was studied. Absorption efficiency (AE) was related to the ingestion rate (IR) following the non-lineal equation AE = 0.836 + e-0.64/IR (P 0.01; n = 26; r² = 0.321) No significant relationship as found between AE and clam live weight, whereas there was a relationship between absorption rate (AR) and IR, following the expression AR = 0.8248 IR - 0.0344 (P 0.001; n = 26; r² = 0.964) The maintenance food ration for a 2 g (live weight) clam was estimated as 1.528 J/h, equivalent to a daily food ration of 0.08 mg organic matter/g clam live weight.Se estudia el efecto de la ingestión de alimento y el tamaño de las almejas sobre la eficiencia de absorción, la tasa de absorción y el consumo de oxígeno de Ruditapes decussatus (L., 1758). La eficiencia de absorción (EA) se relaciona con la tasa de ingestión (TI) siguiendo el modelo no lineal EA = 0,836 + e-0,64/TI (P 0,01; n = 26; r² = 0,321) Entre EA y el peso vivo de las almejas no existe una relación significativa, mientras que sí la hay entre la tasa de absorción (TA) y TI, y responde a la ecuación TA = 0,8248 TI - 0,0344 (P 0,001; n = 26; r² = 0,964) La ración de mantenimiento de una almeja de 2 g de peso vivo es de 1,528 J/h, que se corresponde con una dieta diaria de 0,08 mg de materia orgánica por gramo de peso vivo.Instituto Español de Oceanografí