First long-term trajectory of an ocean sunfish (Mola mola L.) from the northwestern Mediterranean.

The ocean sunfish is a large fish for which many aspects of its ecology and biology are still poorly known. Electronic tagging was used to provide the first information on the movements of an ocean sunfish from the northwestern Mediterranean. The sunfish moved towards the Gibraltar strait over the year and displayed substantial movements in the water column. The potential of the tagging technique employed for studying its behavior and long-term migratory dynamics, and assessing the post-release survival of ocean sunfish is highlighted.

New northerly limit for the sharptail mola in the northeast Atlantic: first sighting of Masturus lanceolatus in the northeast Irish Sea.

The ocean sunfishes are currently represented by five species within three genera: Mola mola (Linnaeus, 1758), Mola alexandrini (Ranzani, 1839), Mola tecta (Nyegaard, Sawai, Gemmell, Gillum, Loneragan, Yamanoue & Stewart, 2017) (Sawai et al., 2018), Masturus lanceolatus (Lienard, 1840), and Ranzania laevis (Pennant, 1776). Growing conservation concerns have led to an ongoing re-examination of their classification status on the International Union for the Conservation of Nature Red Lists, a process requiring the latest data to best support their conservation management on a global scale. Here we report the first sighting of Masturus lanceolatus in the northeast Irish Sea, representing a new northerly range limit for this species in the northeast Atlantic. The species is more commonly reported in tropical seas, and in the Western Atlantic they occur from North Carolina in the United States to southeast Brazil. This sighting increases the most northerly range limit by 2610 km, providing additional insight into the ecology and potentially changing distribution of this generally considered tropical megafaunal species.

[Risdiplam for the treatment of spinal muscular atrophy]. / Risdiplam pri lechenii spinal'noi myshechnoi atrofii.

Spinal muscular atrophy (SMA) is a devastating disease that is the leading genetic cause of death in infants and young children. It includes a broad spectrum of phenotypes that are classified into clinical groups based on the age of onset and maximum motor function achieved. The most common form of SMA is due to a defect in the survival motor neuron 1 gene (SMN1) localized to 5q11.2-q13.3. The development of clinical symptoms and disease progression is thought to be due to decreased levels of survival motor neuron (SMN) protein. SMA type 1 results in almost inevitable mortality within the first 2 years of life. The first two drugs approved globally for the treatment of SMA were the antisense oligonucleotide nusinersen (Spinraza), and the gene therapy onasemnogene abeparvovec-xioi (Zolgensma). Both interventions have approval and restrictions on use in different countries around the world. Despite these approved therapies, the medical unmet need in SMA (the majority of patients with SMA are not on a disease-modifying therapy) remains high with therapies in the pipeline to address some of the remaining limitations. The third and more recently approved drug for SMA is risdiplam (Evrysdi), an orally administered, centrally and peripherally distributed small molecule that modulates SMN2 pre-mRNA splicing toward the production of full-length SMN2 mRNA to increase functional SMN protein levels. In Russia the drug risdiplam was approved for use on November 26, 2020 with indications for the treatment of SMA in patients aged 2 months and older, and in 2023 the indications were expanded - use is allowed starting from the birth. Risdiplam is widely distributed into the CNS and peripheral tissues including muscles. Following risdiplam administration, SMN protein levels compared with baseline levels increase between 2- and 6-fold depending on the SMA phenotype treated. The risdiplam clinical development program currently has four ongoing clinical trials assessing its safety and efficacy. Clinical trials included more than 450 patients receiving risdiplam to date, has been well tolerated and no treatment-related safety findings leading to study withdrawal have been observed. Data from real clinical practice - more than 11.000 patients worldwide receive therapy with risdiplam, also confirm the safety and good tolerability of the drug.

First evidence of microplastic ingestion in the ocean giant sunfish (Mola mola).

Mola mola is the largest teleost inhabiting our ocean and the presence of microplastics (MP) in this flagship species was, before this study, never described. Thus, this investigation focused on analysing MP ingestion in 53 ocean giant sunfish in the Northeast Atlantic Ocean. A total of 116 MP were found in 79% of the specimens, with a median of 1 MP.ind-1, ranging from 0 to 11 MP.ind-1. Seasonal differences were observed, with more fibers registered in specimens caught in autumn. Among the different size classes observed, the smallest category (<300 µm) was the most frequent (43%). Blue (43%) was the most prevalent color, followed by green (29%) and black (10%). The majority of fragments were styrene acrylic copolymer (53%), while most fibers were rayon (78%). These findings emphasize that the ocean sunfish population crossing the southern waters of Portugal is exposed to microplastic pollution and highlight the need for effective management policies to address plastic pollution in marine ecosystems.

Monogenoidea Communities Differ Between Male Morphotypes of Bluegill Sunfish (Lepomis macrochirus).

PURPOSE: Bluegill sunfish (Lepomis macrochirus) are a North American sport fish that exhibit two different male morphotypes. Alpha-males are large, colorful, territorial, and have significant parental investment, while ß-males are small, drab, and have two reproductive phenotypes, neither of which involves parental investment. Due to the two different reproductive strategies, the level of interaction between congenerics varies, which may impact parasites that are spread via close contact, such as Monogenoidea that infect the gills. Monogeneans are ectoparasites on the gills and skin of fish hosts that may cause significant pathology in high numbers and be an indicator of host behavior and interaction between hosts. METHODS: In this study, 328 L. macrochirus (106 α-males, 92 ß-males, and 130 females) were necropsied from 8 lakes and ponds in northwestern Virginia to identify and enumerate monogenean parasites from the gills. RESULTS: Alpha-males had a significantly greater parasite abundance and species richness compared to ß-males. This may be due to the increased size and surface area of gills in α-males, increased interaction with females during mating, and stationary behavior when guarding nests, which enhanced the chances of α-males contracting the parasites. This also led to significant differences in the monogenean communities infecting the two morphotypes, which were also significantly influenced by the size of the hosts. CONCLUSIONS: It is important in future studies regarding parasitism that behavioral morphotypes within a sex, such as α-male and ß-male L. macrochirus in this study, be treated separately as behavioral and morphometric differences between them can potentially lead to differences in parasitism.

Two-year efficacy and safety of risdiplam in patients with type 2 or non-ambulant type 3 spinal muscular atrophy (SMA).

Risdiplam is an oral, survival of motor neuron 2 (SMN2) pre-mRNA splicing modifier approved for the treatment of spinal muscular atrophy (SMA). SUNFISH (NCT02908685) Part 2, a Phase 3, randomized, double-blind, placebo-controlled study, investigated the efficacy and safety of risdiplam in type 2 and non­ambulant type 3 SMA. The primary endpoint was met: a significantly greater change from baseline in 32-item Motor Function Measure (MFM32) total score was observed with risdiplam compared with placebo at month 12. After 12 months, all participants received risdiplam while preserving initial treatment blinding. We report 24-month efficacy and safety results in this population. Month 24 exploratory endpoints included change from baseline in MFM32 and safety. MFM­derived results were compared with an external comparator. At month 24 of risdiplam treatment, 32% of patients demonstrated improvement (a change of ≥ 3) from baseline in MFM32 total score; 58% showed stabilization (a change of ≥ 0). Compared with an external comparator, a treatment difference of 3.12 (95% confidence interval [CI] 1.67-4.57) in favor of risdiplam was observed in MFM-derived scores. Overall, gains in motor function at month 12 were maintained or improved upon at month 24. In patients initially receiving placebo, MFM32 remained stable compared with baseline (0.31 [95% CI - 0.65 to 1.28]) after 12 months of risdiplam; 16% of patients improved their score and 59% exhibited stabilization. The safety profile after 24 months was consistent with that observed after 12 months. Risdiplam over 24 months resulted in further improvement or stabilization in motor function, confirming the benefit of longer-term treatment.

A reference genome for Bluegill (Centrarchidae: Lepomis macrochirus).

North American sunfishes (Family Centrarchidae) are among the most popular sportfish throughout the United States and Canada. Despite the popularity of sunfishes, their ecological importance, and their extensive stocking and aquacultural history, few molecular studies have examined the evolutionary relationships and species boundaries among members of this group, many of which are known to hybridize. Here, we describe a chromosome-scale genome assembly representing Bluegill (Lepomis macrochirus), one of the most widespread centrarchid species. By combining long-read, Oxford Nanopore sequencing data with short-insert, whole-genome and HiC sequence reads, we produced an assembly (Lm_LA_1.1) having a total length of 889 Mb including 1,841 scaffolds and having a scaffold N50 of 36 Mb, L50 of 12, N90 of 29 Mb, and L90 of 22. We detected 99% (eukaryota_odb10) and 98% (actinopterygii_odb10) universal single-copy orthologs (BUSCOs), and ab initio gene prediction performed using this new assembly identified a set of 17,233 genes that were supported by external (OrthoDB v10) data. This new assembly provides an important addition to the growing set of assemblies already available for spiny-rayed fishes (Acanthomorpha), and it will serve as a resource for future studies that focus on the complex evolutionary history of centrarchids.

Differential Strigeid Infection Patterns in Male Morphotypes of Bluegill Sunfish (Lepomis macrochirus).

PURPOSE: Behavioral variation among conspecific organisms can have substantial ecological impacts, particularly affecting parasite infection. Bluegill sunfish (Lepomis macrochirus) exhibit multiple male reproductive morphotypes that differ in their size, feeding dynamics, and reproductive behavior. This study investigated how these morphological and ecological differences contribute to the patterns of infection by strigeid trematodes. METHODS: A total of 1961 L. macrochirus was collected from 14 lakes and ponds in northwestern Virginia, USA, and were necropsied to identify and enumerate three common strigeid parasites, white grub (Posthodiplostoum spp.), black grub (Uvulifer ambloplitis), and yellow grub (Clinostomum marginatum) infecting the fish and determine if there were different infection patterns among sexes and morphotypes. RESULTS: Strigeid infections in L. macrochirus α-males were in greater abundance compared to females and ß-males. Additionally, α-males had greater strigeid infection in the kidneys and fins, while females and ß-males accumulated more parasites in the liver and body tissues. CONCLUSIONS: Increased nesting responsibilities and potential interaction with snail intermediate hosts by α-males may lead to the differences in infection patterns. The distinction of morphotypes revealed significant differences in abundance and distribution of parasite infections between the sexes of L. macrochirus, trends that were masked when male morphotypes are combined.

Evolutionary divergence in phenotypic plasticity shapes brain size variation between coexisting sunfish ecotypes.

Mechanisms that generate brain size variation and the consequences of such variation on ecological performance are poorly understood in most natural animal populations. We use a reciprocal-transplant common garden experiment and foraging performance trials to test for brain size plasticity and the functional consequences of brain size variation in Pumpkinseed sunfish (Lepomis gibbosus) ecotypes that have diverged between nearshore littoral and offshore pelagic lake habitats. Different age-classes of wild-caught juveniles from both habitats were exposed for 6 months to treatments that mimicked littoral and pelagic foraging. Plastic responses in oral jaw size suggested that treatments mimicked natural habitat-specific foraging conditions. Plastic brain size responses to foraging manipulations differed between ecotypes, as only pelagic sourced fish showed brain size plasticity. Only pelagic juveniles under 1 year-old expressed this plastic response, suggesting that plastic brain size responses decline with age and so may be irreversible. Finally, larger brain size was associated with enhanced foraging performance on live benthic but not pelagic prey, providing the first experimental evidence of a relationship between brain size and prey-specific foraging performance in fishes. The recent post-glacial origin of these ecotypes suggests that brain size plasticity can rapidly evolve and diverge in fish under contrasting ecological conditions.

PARASITISM IN HYBRID SUNFISH (LEPOMIS SPP.): PATTERNS OF INFECTION AT THE INDIVIDUAL AND COMMUNITY LEVEL.

Sunfish (Lepomis spp.) are among the most common piscine inhabitants of freshwater lakes and ponds in North America. Lepomis spp. breed at the same time creating hybrid zones, where genetically distinct populations mate and produce mixed offspring that are sexually viable hybrids. One aspect of hybridization that may have important consequences is parasitism and its patterns of recruitment in the hybrid sunfish. This study investigated these patterns both at the level of the individual parasite species as well as in the parasite communities infecting the fish. Two sample sites possessing hybrid sunfish populations were investigated: 1 system had bluegill sunfish (Lepomis macrochirus), redear sunfish (Lepomis microlophus), and their hybrids, while the other system had bluegill sunfish (L. macrochirus), green sunfish (Lepomis cyanellus), and their hybrids. The hybrids were infected by mostly generalist parasites that commonly infect all Lepomis spp. Most of the individual parasite species followed a dominance pattern (59.1%) of infection, where parasite abundance in hybrids resembled at least one of the parental species, with the remainder exhibiting intermediate levels of parasitism, supporting an additive pattern of parasite recruitment (40.1%). At the community level, the patterns of parasite recruitment differed in L. macrochirus × L. microlophus hybrids, which showed a dominance pattern, and L. macrochirus × L. cyanellus hybrids, which showed an additive pattern of parasite recruitment. These differences in parasite recruitment between hybrid groups may be attributed to varying degrees of dietary and niche overlap between the parental species in the 2 study systems.

Stress response gene family expansions correlate with invasive potential in teleost fish.

The bluegill sunfish Lepomis macrochirus and the closely related redear sunfish Lepomis microlophus have important ecological and recreational value and are widely used for research and aquaculture. While both species have been introduced outside of their native ranges, only the bluegill is considered invasive. Here, we report de novo transcriptome assemblies for these fish as a resource for sunfish biology. Comparative analyses of the transcriptomes revealed an unexpected, bluegill-specific expansion in the HSP70 and HSP90 molecular chaperone gene families. These expansions were not unique to the bluegill as expansions in HSP70s and HSP90s were identified in the genomes of other teleost fish using the NCBI RefSeq database. To determine whether gene family expansions are specific for thermal stress responses, GST and SOD gene families that are associated with oxidative stress responses were also analyzed. Species-specific expansions were also observed for these gene families in distinct fish species. Validating our approach, previously described expansions in the MHC gene family were also identified. Intriguingly, the number of HSP70 paralogs was positively correlated with thermotolerance range for each species, suggesting that these expansions can impact organismal physiology. Furthermore, fish that are considered invasive contained a higher average number of HSP70 paralogs than non-invasive fish. Invasive fish also had higher average numbers of HSP90, MHC and GST paralogs, but not SOD paralogs. Taken together, we propose that expansions in key cellular stress response gene families represent novel genetic signatures that correlate with invasive potential.

Seasonal changes in mitochondrial bioenergetics and physiological performance of the bluegill sunfish, Lepomis macrochirus, from a shallow, Midwest river.

As global temperature shifts due to anthropogenic impacts, seasonal temperatures in shallow aquatic ecosystems are expected to increase. Previous studies on freshwater fishes that experience significant temperature changes during the annual seasons found pronounced physiological restructuring not observed in animals inhabiting more thermally stable environments. Studies evaluating mitochondrial bioenergetics in fish are often performed on animals acclimated to constant temperatures in the laboratory. However, natural habitats are much more complex. Fishes may experience substantial daily and seasonal variation in temperature, energy requirements and resource availability, which are impossible to emulate on acclimation studies. Our study explores the effects of these more complex natural environments on whole-organism thermal tolerance and mitochondrial bioenergetics in bluegill sunfish (Lepomis macrochirus), a native fish to the temperate zone of North America. Compensatory mechanisms and variations in physiological thresholds were observed in specimens acclimatized to the fall season compared to specimens acclimatized to spring and summer seasons. Somatic indices, such as relative weights and hepatosomatic indices, showed significant differences across seasons and critical thermal maxima significantly decreased in the cold acclimatized specimens. Liver mitochondria from L. macrochirus also showed significantly higher uncoupled proton conductance, cytochrome c oxidase (COX) activity, and reduced respiratory control ratios in individuals sampled in the colder season. These findings suggest that mechanisms regulating proton conductance and COX activity modulate mitochondrial function across seasons to sustain physiological fitness in ectotherms inhabiting shallow, inland aquatic habitats.

Comparison of the in vitro assays to investigate the hepatic metabolism of seven pesticides in Cyprinus carpio and Oncorhynchus mykiss.

Liver S9 fractions from common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) were incubated with seven pesticides (fenamidone, fenoxaprop-p-ethyl, penflufen, spirotetramat, tebuconazole, tembotrione and trifloxystrobin) and the metabolic pathways of the applied chemicals were determined by HPLC-high-resolution mass spectrometry. Five of the seven pesticides (fenamidone, penflufen, spirotetramat, trifloxystrobin and fenoxaprop-p-ethyl) revealed a higher metabolic capacity of rainbow trout liver fractions compared to carp liver fractions. The other two pesticides (tebuconazole and tembotrione) showed a similar and marginal biotransformation for liver S9 fractions of both species. Furthermore, four compounds (penflufen, spirotetramat, tembotrione and tebuconazole) were incubated with cryo-preserved hepatocytes of rainbow trout showing additional conjugated metabolites compared to liver S9 fractions. The incubations were performed with concentrations of 1 and 10 µM for experiments with liver S9 fractions and 5 µM with hepatocytes for up to 120 (liver S9 fractions) or 240 min (hepatocytes). A set of positive controls was used to confirm the metabolic capability of the in vitro systems. The comparison of the in vitro results from hepatocyte assays of penflufen and tebuconazole with the data from corresponding in vivo studies performed according to OECD (Organisation for Economic Co-operation and Development) guideline 305 exhibited a similar metabolic behavior for these pesticides and emphasizes the reliability of the in vitro assays. Besides investigation of the metabolism of plant protection products for research purposes, inter-species comparison by in vitro assays and the use of PBTK modelling approaches will allow improved environmental and dietary risk assessments.

A foraging ocean sunfish and the 'nearest neighbor' problem.

A predator that preys on randomly-distributed stationary energetically-equivalent small prey will probably choose its next prey to be the nearest one. But what if no prey is found within the detection range of the predator? It is hypothesized that in this case the predator will move along an arbitrary chosen direction until a prey is detected, and turn towards it. In a stochastic environment this strategy leads to a certain distribution function of distances that the predator moves between consequent prey catches. It is shown that when the detection range of the predator exceeds the average distance between prey, this distribution function becomes the nearest neighbor distribution function, whereas; wherew when the detection range is small as compared with the average distance between prey, it becomes the exponential distribution, as the distribution of distances between neighbors on a line. In the first case, the average distance between catches becomes roughly half the average distance between prey; in the second case, it becomes inversely proportional to the square of the detection range. Ocean sunfish preys on practically stationary jellyfish at depth of more than a hundred meters, in dim light. Plausibly, it can detect jellyfish only at close quarters, and hence its detection range is probably small as compared with the average distance between prey. Analysis of the tracking data from seven animals over a few days yielded many thousands of swimming segments separating consequent prey catches. Indeed, lengths of these segments were shown to have the exponential distribution. This finding not only supports the initial hypothesis of this study, but also reveals the fragility of the energetic balance of this animal. A two-fold decrease in the detection range (e.g. due to a decreased visibility) is expected to increase the average distance it moves between catches four-fold, and hence decrease its specific energy intake (the number of jellyfishes per distance moved) by the same rate.

Tissue and gender-related differences in the elemental composition of juvenile ocean sunfish (Mola spp.).

Trace elements are potentially critical contaminants of aquatic environments and fish, occupying upper trophic levels, are especially vulnerable to bioaccumulation. Due to public health concerns, however, data on the elemental composition of non-commercially important marine species are particularly lacking. Ocean sunfish (Mola spp.) attain a low commercial value worldwide and information on their elemental composition is limited. In this context, we examined the concentration of 11 trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb) in eight tissues [brain, gills, gelatin (subcutaneous white gelatinous layer), gonads, spleen, liver, white muscle and red muscle] of 20 juvenile specimens (37.5-85.5 cm TL). Gender-related differences were solely found in the gonads and chiefly for essential elements possibly as a result of their importance in embryo development. Overall, Zn and As were the elements observed in greatest concentrations in body tissues. The considerably high presence of As should be related to the dietary preferences of juvenile ocean sunfish. Considerable inter-individual variability in the concentration of each element in any given tissue was observed, especially in the liver, likely originating from the inclusion of both benthic and pelagic prey in the diet of analysed fish. Greatest elemental loads were found in the liver and gills whereas lowest loads were observed in white muscle, brain and gelatin. Moreover, a clear distinction in elemental load and elemental composition was observed between white and red muscles, likely deriving from existing divergent metabolism-related physiological adaptations linked to their different roles in locomotion.

Interspecific and intraspecific comparisons reveal the importance of evolutionary context in sunfish brain form divergence.

Habitats can select for specialized phenotypic characteristics in animals. However, the consistency of evolutionary responses to particular environmental conditions remains difficult to predict. One trait of great ecological importance is brain form, which is expected to vary between habitats that differ in their cognitive requirements. Here, we compared divergence in brain form and oral jaw size across a common littoral-pelagic ecological axis in two sunfishes at both the intraspecific and interspecific levels. Brain form differed between habitats at every level of comparison; however, divergence was inconsistent, despite consistent differences in oral jaw size. Pumpkinseed and bluegill species differed in cerebellum, optic tectum and olfactory bulb size. These differences are consistent with a historical ecological divergence because they did not manifest between littoral and pelagic ecotypes within either species, suggesting constraints on changes to these regions over short evolutionary time scales. There were also differences in brain form between conspecific ecotypes, but they were inconsistent between species. Littoral pumpkinseed had larger brains than their pelagic counterpart, and littoral bluegill had smaller telencephalons than their pelagic counterpart. Inconsistent brain form divergence between conspecific ecotypes of pumpkinseed and bluegill sharing a common littoral-pelagic habitat axis suggests that contemporary ecological conditions and historic evolutionary context interact to influence evolutionary changes in brain form in fishes.

Exposure to 17ß estradiol causes erosion of sexual dimorphism in Bluegill (Lepomis macrochirus).

Estrogenic compounds including 17ß estradiol (or E2) are known to negatively affect the reproductive system of many animals, including fish, leading to feminization, altered sex ratio, reduced fecundity, and decreased gonadosomatic index. The objective of this study was to evaluate the effects of varying concentrations of water-soluble 17ß estradiol exposure on the external morphology of Bluegill. An experiment was set up where fish were individually maintained in 10-g tanks and exposed to 17ß estradiol concentrations of 40 and 80 ng/L or no 17ß estradiol exposure (the control). Fish were exposed for 21 days, with 17ß estradiol replenished each week to account for 17ß estradiol half-life. Fish were photographed laterally before and after the 21-day exposure to 17ß estradiol. Landmark-based geometric morphometrics were conducted in MorphoJ and canonical variate and discriminant function analysis were used to compare the morphological changes in the fish under 17ß estradiol exposure. The results showed that 17ß estradiol exposure caused male dimorphic characters to change in Bluegill by becoming less prevalent. Specifically, there was a narrowing of the caudal peduncle, smaller nape protrusion, reduced opercular flap and pectoral fin, and a deeper body in the exposed groups compared with control fish under both concentrations. This research highlights the widespread effects of 17ß estradiol on fish health beyond the reproductive system, which could have important conservation implications by affecting mate selection and reducing reproductive success.

Isolating the effects of ontogenetic niche shift on brain size development using pumpkinseed sunfish ecotypes.

A functional relationship between relative brain size and cognitive performance has been hypothesized. However, the influence of ontogenetic niche shifts on cognitive performance is not well understood. Increases in body size can affect niche use but distinguishing nonecologically relevant brain development from effects associated with ecology is difficult. If survival is enhanced by functional changes in ecocognitive performance over ontogeny, then brain size development should track ontogenetic shifts in ecology. We control for nonecologically relevant brain size development by comparing brain growth between two ecotypes of Pumpkinseed sunfish whose ecologies diverge over ontogeny from a shared juvenile niche. Brain size differs between ecotypes from their birth year onwards even though their foraging ecology appears to diverge at age 3. This finding suggests that the eco-cognitive requirements of adult niches shape early life brain growth more than the requirements of juvenile ecology.

First report of megalocytivirus (iridoviridae) in cultured bluegill sunfish, Lepomis macrochirus, in China.

The bluegill sunfish, Lepomis macrochirus, is an important aquacultural and recreational species in southern China because of its excellent taste, rapid growth rate, and good looks. At present, few pathogens are known to affect the bluegill sunfish. However, an iridovirus-like disease recently caused heavy losses to the bluegill sunfish aquaculture industry in Guangdong, China. We report that a virus, designated BSMIV-SD-20171020, was isolated from diseased bluegill sunfish in China. The isolate was efficiently propagated in a Chinese perch brain (CPB) cell line. The cytopathic effect was observed, the MCP gene PCR amplified, and the virus observed with electron microscopy. Its viral titer in CPB cells reached 104.13 TCID50 mL-1. The mortality rate was 100% when bluegill sunfish were challenged with BSMIV-SD-20171020 at a dose of 103.13 TCID50/fish. A histopathological examination revealed basophilic hypertrophied cells in the intestine, liver, and spleen. A nucleotide sequence alignment and phylogenetic analysis of the major capsid protein revealed that isolate BSMIV-SD-20171020 is the species Infectious spleen and kidney necrosis virus (ISKNV), in the genus Megalocytivirus.

Body size and season influence elemental composition of tissues in ocean sunfish Mola mola juveniles.

The effects of body size and season on the elemental composition of ocean sunfish Mola mola were assessed for the first time. A total of 57 by-caught juvenile specimens measuring between 31.8 and 120.3 cm were sampled in spring and autumn. Concentrations of trace elements (three essential - Co, Cu, Zn, and three non-essential - As, Cd, Pb) were determined in five body tissues [gills, gelatin (subcutaneous white gelatinous layer), liver, white muscle and red muscle]. Elemental composition of M. mola tissues was found to vary with both body size and season. When an effect of size was verified, the most common trend was a decrease in elemental levels with increasing fish size, most likely deriving from the fast growth rate of this fish (i.e. dilution effect) and the occurrence of an ontogenetic shift in dietary preferences. Differently, Zn levels increased with fish size in both gills and red muscle, potentially deriving from a greater physiological need in those tissues as fish grow. Seasonal differences in trace element levels were observed for approximately half of the studied cases (tissue/trace element) with greater elemental concentrations being mostly found in autumn. Such pattern was most obvious in liver tissue, presumably resulting from a greater dietary elemental uptake in the end of summer/autumn. A general absence of seasonal differences was observed in the gills, white muscle and red muscle. Interestingly, a trend of enhanced concentrations in spring was observed for gelatin, potentially deriving from past long-term differences in exposure to trace elements.