Prognostic factors of progressive fibrotic hypersensitivity pneumonitis: a large, retrospective, multicentre, observational cohort study.

Background: Fibrotic hypersensitivity pneumonitis (fHP) is an immune-mediated interstitial lung disease caused by sensitisation to chronic allergen inhalation. This study aimed to determine prognostic indicators of progression and mortality in fHP. Methods: This was a retrospective, multicentre, observational, cross-sectional cohort study of consecutive patients diagnosed with fHP from 1 January 2012 to 31 December 2021. Multivariate Cox regression analyses were used to calculate hazard ratios (HRs) with 95% confidence intervals for predictors of progression and survival. Results: A total of 403 patients were diagnosed with fHP: median (interquartile range) age 66.5 (14.0) years, 51.9% females and 55.1% never-smokers. The cause of fHP was mainly fungal (39.7%) or avian (41.4%). Lung biopsy was performed in 269 cases (66.7%). In the whole cohort the variables that were related to mortality or lung transplant were older age (HR 1.08; p<0.001), percentage predicted forced vital capacity (HR 0.96; p=0.001), lymphocytosis in bronchoalveolar lavage (BAL) (HR 0.93; p=0.001), presence of acute exacerbation during follow-up (HR 3.04; p=0.001) and GAP (gender, age and lung physiology) index (HR 1.96; p<0.01). In the group of biopsied patients, the presence of fibroblastic foci at biopsy (HR 8.39; p<0.001) stands out in multivariate Cox regression analyses as a highly significant predictor for increased mortality or lung transplant. GAP index (HR 1.26; p=0.009), lymphocytosis in BAL (HR 0.97; p=0.018) and age (HR 1.03; p=0.018) are also predictors of progression. Conclusions: The study identified several prognostic factors for progression and/or survival in fHP. The presence of fibroblastic foci at biopsy was a consistent predictor for increased mortality and the presence of lymphocytosis in BAL was inversely related to mortality.

Temperature and prey density drive growth and otolith formation of the world's most valuable fish stock.

Peruvian anchovy (Engraulis ringens) represents the largest single-species fishery worldwide. Knowledge on how temperature and prey availability influences growth and age estimation during marine fish early life stages is critical for predicting bottom-up processes impacting stock productivity under changing environmental conditions. We reared Peruvian anchovy larvae at two temperatures (14.5 and 18.5 °C) and prey concentrations [high (HF), and low (LF)] from 6 to 30 days post-hatch (dph) to measure growth rate and examine daily deposition of otolith increments. Peruvian anchovy larvae grew faster at 18.5 °C compared to 14.5 °C. Larvae reared at low prey concentration (18.5-LF) and low temperature (14.5-HF) grew 61 and 35% slower, respectively, than those at high prey and warm temperature (18.5-HF). Age and growth rates of larvae were well depicted in the otolith microstructure of well-fed larvae at 18.5 °C. However, larvae reared at 18.5-LF or 14.5-HF, had only 55 and 49% of the expected number of daily otolith increments. Our results suggest caution when attempting to explore how ocean processes regulate small pelagic stocks, the productivity of which are largely driven by changes in the survival and growth of young larvae.

[Highlights of the 55th SEPAR Congress]. / Highlights del 55.° Congreso SEPAR.

The 55th SEPAR Congress was held in Pamplona from 2 to 4 of June 2022. Once again, it was the referral scientific meeting for specialists in pulmonology, thoracic surgery, nursing, physiotherapy, paediatric respiratory diseases and other disciplines involved in respiratory care. The Spanish Society of Pulmonology and Thoracic Surgery showed its national and international leadership in the management of respiratory diseases, which was reflected in a program with an excellent content and a high scientific level. In this review, we offer a summary of some notable aspects covered in six selected areas of interest: pulmonary vascular diseases, non-invasive mechanical ventilation and sleep disorders, asthma, chronic obstructive pulmonary disease (COPD), interstitial lung diseases (ILD), and interventional pulmonolgy and lung transplant.

Intravenous cyclophosphamide improves functional outcomes in interstitial lung disease related to idiopathic inflammatory myopathies.

OBJECTIVE: To compare the efficacy, toxicity and glucocorticoid (GC)-sparing effects of intravenous cyclophosphamide (iv CYC) with other immunosuppressive regimes as the induction treatment for Idiopathic Inflammatory Myopathy-Related Interstitial Lung Disease (IIM-ILD). METHODS: Observational comparative study of patients with IIM-ILD from the EPIMAR and Cruces cohorts. The main efficacy outcome was a 6 to 12-month improvement >10% in the forced vital capacity (FVC) from baseline. RESULTS: Overall, 47 patients were included: 22 (47%) in the CYC group and 25 (53%) in the non-CYC group (32% azathioprine, 28% GC alone, 20% mycophenolate, 16% calcineurin-inhibitors and methotrexate and 4% rituximab). 81% patients were female with a mean age of 50.4 years. FVC improvement was achieved by 64% patients in the CYC group vs. 32% in the non-CYC group (p = 0.03). In the logistic regression model, CYC was identified as the only independent predictor of FVC improvement (OR=3.97, 95% CI 1.07-14.75). Patients in the CYC group received more methyl-prednisolone pulses (MP) (59% vs. 28% in the non-CYC group, p = 0.03), less initial GCs doses >30 mg/d (19% vs. 77%, p = 0.001) and lower 6-month average doses of prednisone (11 mg/d vs. 31.1 mg/d, p = 0.001). CONCLUSION: iv CYC showed better functional outcomes than other immunosuppressants in IIM-ILD. The additional use of MP is likely to potentiate the effects of CYC and allows lowering prednisone doses. Therefore, CYC in combination with MP could be considered as the first line induction therapy in IIM-ILD, without limiting its use to rapidly progressive, life-threatening or refractory disease.

Desarrollo de una solución integrada para pacientes con dolor crónico portadores de neuroestimulador en tiempos del COVID-19: una aplicación para móvil con centro de soporte / Development of an integrated solution for patients with neurostimulator for chronic pain in times of COVID-19: A mobile application with a support center

Introducción El dolor crónico es una de las afecciones más prevalentes en el mundo. El tratamiento con neuroestimuladores se realiza en los casos más extremos tras una cuidadosa selección, y demanda una gran inversión de recursos en su seguimiento. En estos momentos de pandemia por la COVID-19, presentamos una solución integrada para el seguimiento de estos de pacientes, que incluye el desarrollo de una aplicación para dispositivos móviles y un centro de soporte para seguimiento remoto (CSSR). Material y metodología El proyecto se ha desarrollado basándose en evidencia científica en las siguientes fases: 1) Aprobación de la idea en sesión clínica multidisciplinar de implantes para dolor crónico, 2) Formación de un grupo de expertos, 3) Adaptación del protocolo para el seguimiento de los pacientes con dolor crónico a las características del entorno de un smartphone, 4) Adaptación de la plataforma tecnológica al protocolo clínico (entorno tecnológico y flujo de trabajo entre el hospital y el CSSR) y 5) Evaluación de la calidad mediante encuesta (cuantitativa y cualitativa) con una pequeña muestra de pacientes. Resultados La aplicación de paciente se evaluó solicitando opiniones de los usuarios sobre el diseño y la utilidad de la misma entre los primeros pacientes implantados que la usaron. Se realizaron algunos ajustes menores en relación con el material para descargar, y sobre el texto y el color de la pantalla. Conclusiones El proceso de creación de una solución integrada debe estar basado en principios científicos y acorde con los protocolos establecidos. Un centro de soporte permite asegurar una mayor adherencia al seguimiento y una mejor atención a los pacientes (AU)

Introduction Chronic pain is one of the most prevalent pathologies in the world. Treatment with neurostimulators is carried out in the most extreme cases and requires a large investment of resources. In these times of COVID-19 pandemic, we present a comprehensive solution for monitoring this kind of patient, this solution includes the development of a mobile application and a support center for remote monitoring (SCRM). MMaterial and methodology The project was developed according to the scientific evidence in the following phases: (1) approval in a multidisciplinary clinical committee of implants for chronic pain, (2) setting up a group of experts, (3) protocol adaptation for the follow-up of patients with chronic pain to the Smartphone environment, (4) technology platform adaptation to the clinical protocol (technological environment and workflow between the hospital and the SCRM), and (5) quality evaluation by survey (quantitative and qualitative) of a small series of patients. Results The application was evaluated by asking for user opinions about design and usefulness with the first implanted patients. Some minor adjustments were made concerning downloadable material and screen color and text. Conclusions Developing a comprehensive solution should be based on scientific principles and in accordance with established protocols. A support center ensures greater adherence for follow-up and better patient care (AU)

[Development of an integrated solution for patients with neurostimulator for chronic pain in times of COVID-19: A mobile application with a support center]. / Desarrollo de una solución integrada para pacientes con dolor crónico portadores de neuroestimulador en tiempos del COVID-19: una aplicación para móvil con centro de soporte.

Introduction: Chronic pain is one of the most prevalent pathologies in the world. Treatment with neurostimulators is carried out in the most extreme cases and requires a large investment of resources. In these times of COVID-19 pandemic, we present a comprehensive solution for monitoring this kind of patient, this solution includes the development of a mobile application and a support center for remote monitoring (SCRM). MMaterial and methodology: The project was developed according to the scientific evidence in the following phases: (1) approval in a multidisciplinary clinical committee of implants for chronic pain, (2) setting up a group of experts, (3) protocol adaptation for the follow-up of patients with chronic pain to the Smartphone environment, (4) technology platform adaptation to the clinical protocol (technological environment and workflow between the hospital and the SCRM), and (5) quality evaluation by survey (quantitative and qualitative) of a small series of patients. Results: The application was evaluated by asking for user opinions about design and usefulness with the first implanted patients. Some minor adjustments were made concerning downloadable material and screen color and text. Conclusions: Developing a comprehensive solution should be based on scientific principles and in accordance with established protocols. A support center ensures greater adherence for follow-up and better patient care.

Do Antiangiogenics Promote Clot Instability? Data from the TESEO Prospective Registry and Caravaggio Clinical Trial.

BACKGROUND: Venous thromboembolism (VTE) is a common complication in cancer patients. Much of its morbidity stems from the development of fatal pulmonary embolisms (PE). Little is known about the factors involved in clot stability, with angiogenesis possibly being implicated. METHODS: The database is from the TESEO prospective registry that recruits cancer patients with VTE from 41 Spanish hospitals. Independent validation was conducted in a cohort from the Caravaggio trial. The objective is to evaluate the association between exposure to antiangiogenic therapies and the PE/VTE proportion in oncological patients. RESULTS: In total, 1,536 subjects were evaluated; 58.4% (n = 894) had a PE and 7% (n = 108) received antiangiogenic therapy (bevacizumab in 75%). The PE/VTE proportion among antiangiogenic-treated individuals was 77/108 (71.3%) versus 817/1,428 (57.2%) among those receiving other alternative therapies (p = 0.004). The effect of the antiangiogenics on the PE/VTE proportion held up across all subgroups except for active smokers or those with chronic obstructive pulmonary disease. Exposure to antiangiogenics was associated with increased PEs, odds ratio (OR) 2.27 (95% CI, 1.42-3.63). In the Caravaggio trial, PE was present in 67% of the individuals treated with antiangiogenics, 50% of those who received chemotherapy without antiangiogenic treatment, and 60% without active therapy (p = 0.0016). CONCLUSION: Antiangiogenics are associated with increased proportion of PE in oncological patients with VTE. If an effect on clot stability is confirmed, the concept of thrombotic risk in cancer patients should be reconsidered in qualitative terms.

Effects of ocean acidification over successive generations decrease resilience of larval European sea bass to ocean acidification and warming but juveniles could benefit from higher temperatures in the NE Atlantic.

European sea bass (Dicentrarchus labrax) is a large, economically important fish species with a long generation time whose long-term resilience to ocean acidification (OA) and warming (OW) is not clear. We incubated sea bass from Brittany (France) for two generations (>5 years in total) under ambient and predicted OA conditions (PCO2: 650 and 1700 µatm) crossed with ambient and predicted OW conditions in F1 (temperature: 15-18°C and 20-23°C) to investigate the effects of climate change on larval and juvenile growth and metabolic rate. We found that in F1, OA as a single stressor at ambient temperature did not affect larval or juvenile growth and OW increased developmental time and growth rate, but OAW decreased larval size at metamorphosis. Larval routine and juvenile standard metabolic rate were significantly lower in cold compared with warm conditioned fish and also lower in F0 compared with F1 fish. We did not find any effect of OA as a single stressor on metabolic rate. Juvenile PO2,crit was not affected by OA or OAW in both generations. We discuss the potential underlying mechanisms resulting in the resilience of F0 and F1 larvae and juveniles to OA and in the beneficial effects of OW on F1 larval growth and metabolic rate, but contrastingly in the vulnerability of F1, but not F0 larvae to OAW. With regard to the ecological perspective, we conclude that recruitment of larvae and early juveniles to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures.

FishSizer: Software solution for efficiently measuring larval fish size.

Length and depth of fish larvae are part of the fundamental measurements in many marine ecology studies involving early fish life history. Until now, obtaining these measurements has required intensive manual labor and the risk of inter- and intra-observer variability.We developed an open-source software solution to semi-automate the measurement process and thereby reduce both time consumption and technical variability. Using contrast-based edge detection, the software segments images of a fish larva into "larva" and "background." Length and depth are extracted from the "larva" segmentation while taking curvature of the larva into consideration. The graphical user interface optimizes workflow and ease of usage, thereby reducing time consumption for both training and analysis. The software allows for visual verification of all measurements.A comparison of measurement methods on a set of larva images showed that this software reduces measurement time by 66%-78% relative to commonly used software.Using this software instead of the commonly used manual approach has the potential to save researchers from many hours of monotonous work. No adjustment was necessary for 89% of the images regarding length (70% for depth). Hence, the only workload on most images was the visual inspection. As the visual inspection and manual dimension extraction works in the same way as currently used software, we expect no loss in accuracy.

Development of an integrated solution for patients with neurostimulator for chronic pain in times of COVID-19: A mobile application with a support center.

INTRODUCTION: Chronic pain is one of the most prevalent pathologies in the world. Treatment with neurostimulators is carried out in the most extreme cases and requires a large investment of resources. In these times of the COVID19 pandemic, we present a comprehensive solution for monitoring this kind of patient, this solution includes the development of a mobile application and a support center for remote monitoring (SCRM). MATERIAL AND METHODOLOGY: The project was developed according to the scientific evidence in the following phases: (1) Approval in a multidisciplinary clinical committee of implants for chronic pain, (2) Setting up a group of experts, (3) Protocol adaptation for the follow-up of patients with chronic pain to the Smartphone environment, (4) Technology platform adaptation to the clinical protocol (technological environment and workflow between the hospital and the SCRM), and (5) Quality evaluation by survey (quantitative and qualitative) of a small series of patients. RESULTS: The application was evaluated by asking for user opinions about design and usefulness with the first implanted patients. Some minor adjustments were made concerning downloadable material and screen color and text. CONCLUSIONS: Developing a comprehensive solution should be based on scientific principles and in accordance with established protocols. A support center ensures greater adherence for follow-up and better patient care.

Lung Transplant Improves Survival and Quality of Life Regardless of Telomere Dysfunction.

Introduction: Fibrotic interstitial lung diseases (ILDs) are the first indication for lung transplantation (LT). Telomere dysfunction has been associated with poor post-transplant outcomes. The aim of the study was to evaluate the morbi-mortality and quality of life in fibrotic ILDs after lung transplant depending on telomere biology. Methods: Fibrotic ILD patients that underwent lung transplant were allocated to two arms; with or without telomere dysfunction at diagnosis based on the telomere length and telomerase related gene mutations revealed by whole-exome sequencing. Post-transplant evaluation included: (1) short and long-term mortality and complications and (2) quality of life. Results: Fifty-five percent of patients that underwent LT carried rare coding mutations in telomerase-related genes. Patients with telomere shortening more frequently needed extracorporeal circulation and presented a higher rate of early post-transplant hematological complications, longer stay in the intensive care unit (ICU), and a higher number of long-term hospital admissions. However, post-transplant 1-year survival was higher than 80% regardless of telomere dysfunction, with improvement in the quality of life and oxygen therapy withdrawal. Conclusions: Post-transplant morbidity is higher in patients with telomere dysfunction and differs according to elapsed time from transplantation. However, lung transplant improves survival and quality of life and the associated complications are manageable.

Diagnostic delay of associated interstitial lung disease increases mortality in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease whose main extra-articular organ affected is the lung, sometimes in the form of diffuse interstitial lung disease (ILD) and conditions the prognosis. A multicenter, observational, descriptive and cross-sectional study of consecutive patients diagnosed with RA-ILD. Demographic, analytical, respiratory functional and evolution characteristics were analyzed to evaluate the predictors of progression and mortality. 106 patients were included. The multivariate analysis showed that the diagnostic delay was an independent predictor of mortality (HR 1.11, CI 1.01-1.23, p = 0.035). Also, age (HR 1.33, 95% CI 1.09-1.62, p = 0.0045), DLCO (%) (HR 0.85, 95% CI 0.73-0.98, p = 0.0246), and final SatO2 (%) in the 6MWT (HR 0.62, 95% CI 0.39-0.99, p = 0.0465) were independent predictor variables of mortality, as well as GAP index (HR 4.65, 95% CI 1.59-13.54, p = 0.0051) and CPI index (HR 1.12, 95% CI 1.03-1.22, p = 0.0092). The withdrawal of MTX or LFN after ILD diagnosis was associated with disease progression in the COX analysis (HR 2.18, 95% CI 1.14-4.18, p = 0.019). This is the first study that highlights the diagnostic delay in RA-ILD is associated with an increased mortality just like happens in IPF.

First estimates of metabolic rate in Atlantic bluefin tuna larvae.

Atlantic bluefin tuna is an iconic scombrid species with a high commercial and ecological value. Despite their importance, many physiological aspects, especially during the larval stages, are still unknown. Metabolic rates are one of the understudied aspects in scombrid larvae, likely due to challenges associated to larval handling before and during respirometry trials. Gaining reliable estimates of metabolic rates is essential to understand how larvae balance their high growth needs and activity and other physiological functions, which can be very useful for fisheries ecology and aquaculture. This is the first study to (a) estimate the relationship between routine metabolic rate (RMR) and larval dry weight (DW) (mass scaling exponent) at a constant temperature of 26°C, (b) measure the RMR under light and darkness and (c) test whether the interindividual differences in the RMR are related to larval nutritional status (RNA/DNA and DNA/DW). The RMR scaled nearly isometrically with body size (b = 0.99, 0.60-31.56 mg DW) in contrast to the allometric relationship observed in most fish larvae (average b = 0.87). The results show no significant differences in larval RMR under light and darkness, suggesting similar larval activity levels in both conditions. The size explained most of the variability in RMR (97%), and nutritional condition was unrelated to the interindividual differences in routine metabolism. This is the first study to report the metabolic rates of Atlantic bluefin tuna larvae and discuss the challenges of performing bioenergetic studies with early life stages of scombrids.

Food availability modulates the combined effects of ocean acidification and warming on fish growth.

When organisms are unable to feed ad libitum they may be more susceptible to negative effects of environmental stressors such as ocean acidification and warming (OAW). We reared sea bass (Dicentrarchus labrax) at 15 or 20 °C and at ambient or high PCO2 (650 versus 1750 µatm PCO2; pH = 8.1 or 7.6) at ad libitum feeding and observed no discernible effect of PCO2 on the size-at-age of juveniles after 277 (20 °C) and 367 (15 °C) days. Feeding trials were then conducted including a restricted ration (25% ad libitum). At 15 °C, growth rate increased with ration but was unaffected by PCO2. At 20 °C, acidification and warming acted antagonistically and low feeding level enhanced PCO2 effects. Differences in growth were not merely a consequence of lower food intake but also linked to changes in digestive efficiency. The specific activity of digestive enzymes (amylase, trypsin, phosphatase alkaline and aminopeptidase N) at 20 °C was lower at the higher PCO2 level. Our study highlights the importance of incorporating restricted feeding into experimental designs examining OAW and suggests that ad libitum feeding used in the majority of the studies to date may not have been suitable to detect impacts of ecological significance.

Combined effects of ocean acidification and temperature on larval and juvenile growth, development and swimming performance of European sea bass (Dicentrarchus labrax).

Ocean acidification and ocean warming (OAW) are simultaneously occurring and could pose ecological challenges to marine life, particularly early life stages of fish that, although they are internal calcifiers, may have poorly developed acid-base regulation. This study assessed the effect of projected OAW on key fitness traits (growth, development and swimming ability) in European sea bass (Dicentrarchus labrax) larvae and juveniles. Starting at 2 days post-hatch (dph), larvae were exposed to one of three levels of PCO2 (650, 1150, 1700 µatm; pH 8.0, 7.8, 7.6) at either a cold (15°C) or warm (20°C) temperature. Growth rate, development stage and critical swimming speed (Ucrit) were repeatedly measured as sea bass grew from 0.6 to ~10.0 (cold) or ~14.0 (warm) cm body length. Exposure to different levels of PCO2 had no significant effect on growth, development or Ucrit of larvae and juveniles. At the warmer temperature, larvae displayed faster growth and deeper bodies. Notochord flexion occurred at 0.8 and 1.2 cm and metamorphosis was completed at an age of ~45 and ~60 days post-hatch for sea bass in the warm and cold treatments, respectively. Swimming performance increased rapidly with larval development but better swimmers were observed in the cold treatment, reflecting a potential trade-off between fast grow and swimming ability. A comparison of the results of this and other studies on marine fish indicates that the effects of OAW on the growth, development and swimming ability of early life stages are species-specific and that generalizing the impacts of climate-driven warming or ocean acidification is not warranted.

Effects of warming rate, acclimation temperature and ontogeny on the critical thermal maximum of temperate marine fish larvae.

Most of the thermal tolerance studies on fish have been performed on juveniles and adults, whereas limited information is available for larvae, a stage which may have a particularly narrow range in tolerable temperatures. Moreover, previous studies on thermal limits for marine and freshwater fish larvae (53 studies reviewed here) applied a wide range of methodologies (e.g. the static or dynamic method, different exposure times), making it challenging to compare across taxa. We measured the Critical Thermal Maximum (CTmax) of Atlantic herring (Clupea harengus) and European seabass (Dicentrarchus labrax) larvae using the dynamic method (ramping assay) and assessed the effect of warming rate (0.5 to 9°C h-1) and acclimation temperature. The larvae of herring had a lower CTmax (lowest and highest values among 222 individual larvae, 13.1-27.0°C) than seabass (lowest and highest values among 90 individual larvae, 24.2-34.3°C). At faster rates of warming, larval CTmax significantly increased in herring, whereas no effect was observed in seabass. Higher acclimation temperatures led to higher CTmax in herring larvae (2.7 ± 0.9°C increase) with increases more pronounced at lower warming rates. Pre-trials testing the effects of warming rate are recommended. Our results for these two temperate marine fishes suggest using a warming rate of 3-6°C h-1: CTmax is highest in trials of relatively short duration, as has been suggested for larger fish. Additionally, time-dependent thermal tolerance was observed in herring larvae, where a difference of up to 8°C was observed in the upper thermal limit between a 0.5- or 24-h exposure to temperatures >18°C. The present study constitutes a first step towards a standard protocol for measuring thermal tolerance in larval fish.

Short-term molecular and physiological responses to heat stress in neritic copepods Acartia tonsa and Eurytemora affinis.

Invertebrates inhabiting shallow water habitats represent particularly appropriate organisms for studying the acclimation potential to environmental stress, since they naturally experience large fluctuations in key abiotic factors such as temperature and salinity. We quantified the biochemical- (mRNA transcripts of 78-kDa glucose-regulated protein (grp78), 70-kDa heat shock protein (hsp70), 90-kDa heat shock protein (hsp90), protein synthesis of HSP70) and organismal- (oxygen consumption rates) level responses to acute heat stress on two neritic copepods (Acartia tonsa and Eurytemora affinis) with special emphasis on the role of short-term acclimation. Transcripts of hsp increased with increasing acute temperature exposure and protein quantities (HSP70) were detectable for 30h. In A. tonsa, HSP70 synthesis was also associated with handling stress. In E. affinis, heat-dependent responses were detected in hsp90, grp78 (mRNA) and HSP70 (protein) expression. Acclimation to a warmer temperature significantly decreased the heat stress response in both species. In A. tonsa, short-term acclimation to heat was not detected at the organismal level via metabolic rate. This study reveals interspecific differences in both the gene expression of stress molecules (e.g. hsp90) as well as the stress factors needed to evoke a stress response (heat vs. handling). We demonstrate that cellular stress markers can be useful measures of short-term thermal acclimation in copepods, which may remain undetected by organismal-level measures.

Thermal impacts on the growth, development and ontogeny of critical swimming speed in Atlantic herring larvae.

Increases in swimming ability have a profound influence on larval fish growth and survival by increasing foraging success, predator avoidance and the ability to favorably influence transport. Understanding how development and environmental factors combine to influence swimming performance in aquatic organisms is particularly important during the transition from viscous to inertial environments. We measured the growth, development and ontogenetic changes in critical swimming speed (Ucrit) in Atlantic herring (Clupea harengus) larvae reared at three temperatures (7, 11, 15°C). Temperature had a significant effect on growth rates (from 0.21 at 7°C to 0.34mm·d(-1) at 15°C), and larval morphology-at-length (increased dry weight (DW), body height and developmental rate at warmer temperatures). Temperature-dependent differences in morphology influenced swimming performance (e.g. the exponential increase in Ucrit with increasing body size was faster at warmer temperatures). Larvae entered the transition to an inertial environment (Reynolds numbers ≥300) at body lengths between 15 (15°C) and 17mm (7°C). Inter-individual differences in Ucrit were not related to nutritional condition (RNA·DNA(-1) or DNA·DW(-1)), but were negatively correlated to length-at-age, suggesting a trade-off between growth rate and locomotor activity. The Ucrit data from this and previously published studies suggest that Atlantic herring pass through four activity phases: 1) yolk-sac (<0.6cm·s(-1)), 2) pre-flexion (0.6-3.0cm·s(-1), temperature effect changes with body size), 3) post-flexion (up to 6-8cm·s(-1), Q10~1.8-2.0), 4) juvenile-adult period (20-170cm·s(-1)).

Projected habitat loss for Atlantic herring in the Baltic Sea.

Projected, climate-driven changes in rainfall patterns are expected to alter the salinity (S) of estuaries and larger brackish water bodies, such as the Baltic Sea. Some marine fish larvae are potentially more sensitive to low salinity than older stages, hence we compared the low salinity tolerance of Atlantic herring (Clupea harengus) larvae at the individual and population levels including four populations in the North and Baltic Seas. Acute low salinity tolerance was similar (S = 1.9-2.7) across populations and increased with increasing body size. Based on this physiological threshold and a regionally down-scaled climate model, spawning habitats in the northern and eastern Baltic Sea are projected to be largely unsuitable for herring by 2100. Although adaptive mechanisms may attenuate the effect in some species, the limited physiological tolerance of fish larvae will remain an important bottleneck for the persistence of marine fish populations in brackish waters undergoing climate-driven freshening.

Direct Effects of Microalgae and Protists on Herring (Clupea harengus) Yolk Sac Larvae.

This study investigated effects of microalgae (Rhodomonas baltica) and heterotrophic protists (Oxyrrhis marina) on the daily growth, activity, condition and feeding success of Atlantic herring (Clupea harengus) larvae from hatch, through the end of the endogenous (yolk sac) period. Yolk sac larvae were reared in the presence and absence of microplankton and, each day, groups of larvae were provided access to copepods. Larvae reared with microalgae and protists exhibited precocious (2 days earlier) and ≥ 60% increased feeding incidence on copepods compared to larvae reared in only seawater (SW). In the absence and presence of microalgae and protists, life span and growth trajectories of yolk sac larvae were similar and digestive enzyme activity (trypsin) and nutritional condition (RNA-DNA ratio) markedly declined in all larvae directly after yolk sac depletion. Thus, microplankton promoted early feeding but was not sufficient to alter life span and growth during the yolk sac phase. Given the importance of early feeding, field programs should place greater emphasis on the protozooplankton-ichthyoplankton link to better understand match-mismatch dynamics and bottom-up drivers of year class success in marine fish.