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The grey silverfish Ctenolepisma longicaudatum is a new and serious pest spreading rapidly across Europe. Compared to the silverfish Lepisma saccharinum, it does not depend on relative humidity above 70% and thrives also in new museum buildings, modern storage depositories, apartments, and office buildings. Especially collections of graphic art, modern art on paper, photographs, but also archives and libraries are increasingly affected by this pest. Damage of paper objects has been reported by different authors and institutions across Europe. As these animals live in inaccessible cracks and crevices inside the buildings, we investigated the spread of microorganisms on living grey silverfish, to show a potential additional threat posed by this pest. In 8 locations in Austria living animals were collected with traps and placed for 10 min on agar plates which were incubated for 2 weeks. After incubation of 50 agar plates, between 2 and 20 colonies of fungi were growing on each plate. The most dominant fungal genera were Cladosporium (Cladosporium cladosporioides clade) and Penicillium (Penicillium glabrum, Penicillium decumbens); also, species of the genera Aspergillus, Alternaria, Botrytis, Bartalinia, Byssochlamis, Chaetomium and Mycothypha were found. The diversity of fungi reflects the common fungal community of museums and archives. The spores and mycelial fragments of the fungi are obviously travelling on the legs and bodies of the silverfish.

Water availability, which enables plant growth and animal activity, regulates dryland ecosystem function. In hyper-arid ecosystems, rain cannot support vascular plant growth. Therefore, hyper-arid vegetation is restricted to the lower topography, where runoff accumulates. Typically, food resources originating from areas of dense vegetation are dispersed across the desert floor, enabling animal life in areas lacking vascular plant growth. However, certain regions, such as the hyper-arid upper topography, may be devoid of plant-derived food resources. The present study examined arthropod activity in the upper topography of a hyper-arid desert, in comparison with arthropod activity in the lower topography. Pitfall traps were utilized to compare arthropod activity along unvegetated ridges with activity in parallel, vegetated riverbeds. Surprisingly, the study revealed dense arthropod communities in the barren upper topography. Arthropods collected in the upper topography represented 26% of total arthropod abundance. In addition, the overlap between arthropod identity in the ridges and wadis (i.e., riverbeds) was low, and certain arthropods were strongly affiliated with the ridges. The upper topographic communities included high numbers of silverfish (Zygentoma: Lepismatidae), malachite beetles (Psiloderes), and predatory mites (Acari: Anystidae), and these arthropods were present at various life stages. It remains unclear how arthropod communities can persist in the unvegetated upper topography of the hyper-arid study area. These results raise the possibility that other food sources, independent from vascular plants, may play a significant role in the life history of hyper-arid arthropods.

Intraspecific competition for food can be especially high in colonial breeding seabirds. To minimize colony-induced or annual foraging challenges, diet may vary among individuals, but few studies have simultaneously investigated the effects of both extrinsic conditions (e.g. colony or year effects) and parameters of an individual (e.g. sex, age or individual quality) on diet in seabirds. Using stable isotope analyses, we studied the diet of 214 Adélie penguins Pygoscelis adeliae of known sex, age and breeding quality, nesting in 2 colonies on Ross Island, Antarctica, over 3 breeding seasons. During the study, δ15N and δ13C isotope values were lower in penguins breeding at Cape Crozier compared to those at Cape Bird, revealing a difference in prey proportions. Cape Bird penguins were estimated to consistently consume more energy-rich silverfish Pleuragramma antarctica, while birds at Cape Crozier ate more crystal krill Euphausia crystallorophias. We also found inter-annual differences in diet, with a higher dietary fish proportion in both colonies during 2011. Males had significantly higher δ15N values, indicating a higher fish consumption than females. This sexual segregation in diet was particularly pronounced at Cape Bird, where the overall isotopic niche was wider than at Cape Crozier. Differences in diet among adults of varying ages only existed at Cape Bird, where middle-aged penguins consumed more fish than old and young penguins. This study provides evidence that Adélie penguin diet is largely driven by annual, seasonal and local abundances of prey, with only some individuals selectively foraging for more nutritional prey if prey choices are present.

The earliest branching event in winged insects, one of the core problems regarding early insect evolution, was addressed using characters of the head. The head is arguably one of the most complex body regions in insects and the phylogenetic information content of its features has been demonstrated. In contrast, the wings and other body parts related to the flight apparatus and sperm transmission are not useful in the context of this problem, as the outgroups (silverfish and bristletails) are wingless and transmit spermatophores externally. Therefore, they show profound differences in the organization of the postcephalic body, and assessment of homology and subsequent phylogenetic analysis of features of these body regions is extremely difficult. The core of this study is the investigation of head structures of representatives of the major clades of dragonflies. A detailed description of the head of Lestes virens is presented and was used as a starting point for the compilation of a character set and a character state matrix for the entire Dicondylia (winged insects + silverfish), with a main focus on the placement of dragonflies and consequently the basal branching event within winged insects. Our results indicate a sister-group relationship between a clade Palaeoptera (dragonflies + mayflies) and the megadiverse monophyletic lineage Neoptera. We show that despite considerable structural similarity between the odonate and neopteran mandible, the muscle equipment in dragonflies is more plesiomorphic with respect to Dicondylia than previously known. Odonata and Ephemeroptera also share presumably derived features of the antenna, maxilla, and labial musculature. Parsimony analyses of the head data unambiguously support a clade Palaeoptera. � The Willi Hennig Society 2012.

COVID-19 spread globally and, as there was little immunity, quarantine, isolation, and social distancing became widely practiced. As people were restricted to their homes in many countries, public venues, such as museums, galleries, and historic houses, were typically closed. This allowed insect abundance, under changed conditions, to be explored using traps from the Technical Museum, Schönbrunn Palace, Hofburg Museum, and Weltmuseum in Vienna. The trap contents reveal an increase in Lepisma saccharinum, the common silverfish, as well as in the Zygentoma Ctenolepisma longicaudatum and C. calvum at some museums. Other insects such as Tineola bisselliella, Anthrenus verbasci, and Attagenus smirnovi, though found in reasonable numbers, did not increase. Museum interiors were likely a little cooler and drier during lockdown, but this difference is too small to explain the increased silverfish activity. The larger rooms were certainly quieter, which allowed insects freedom to range more widely. Nevertheless, museums did not observe increased damage to collections from the larger numbers. The infestations during the closures suggest a need for low level cleaning and regular inspections, with an initial focus examining those areas frequented by insects in the past.

The silverfish Neoasterolepisma foreli belongs to the family Lepismatidae within Zygentoma and is well known for the peculiar habit of living in strict association with ant nests (myrmecophily). In...

A new species of silverfish, Persiatelurina daghestaniana Kaplin, sp. nov., is described from Daghestan. It differs from other species of this genus, P. caucasica (Kaplin, 2016) from Abkhazia and P. farsiana Molero et al., 2018 from Southwestern Iran, by the structure of the legs, maxillae, maxillary and labial palps, pronotum, urotergite X, urosternites II and VII, urocoxites VIII and IX, subgenital plate, and ovipositor.

In modern conditions, the problem of pollution of reservoirs with heavy metals becomes especially relevant, especially given the man-made load on surface waters of Ukraine. Heavy metals are among the most dangerous conservative chemical pollutants, due to their physiological and biochemical characteristics of action, as well as transmission through food chains. Also, the danger of heavy metals is that they are bioavailable and enter the fish ponds not only during the water harvest, but also during the application of fertilizers to fields or feeding fish. Fish that complete the trophic chain of the reservoir are the end products of the fishery activities of the enterprise and directly accumulate heavy metals. At the same time, such heavy metals as Fe, Zn, Mn are essential, ie they in physiological concentrations are vital for the implementation of regulatory functions in fish. However, the body of fish accumulates heavy metals that even in small concentrations adversely affect its physiological state. The aim of the study was to determine the characteristics of the accumulation of heavy metals in the body of young carp fish in typical pond farms of Dnipropetrovsk region. The object of research were this year's scaly carp and silver carp, which were grown in Tarom and Krynychany fisheries. In the cities of heavy metals in water ponds and the carcass of fish were determined by atomic absorption spectrophotometer her on a spectrophotometer S115-M1. The results of the study show that the content of Pb and Fe in the water of ponds of both fisheries did not exceed the MPC (SOU, 2006). The Cd content in the water of the Krynychany fish farm exceeded the maximum concentration limit by 2 times. The level of Mn in the water of the Tarom fish farm was 3 times higher than the MPC. The level of Zn content in both fish farms exceeded the permissible concentrations by almost 3 times. The concentration of Cu exceeded the MPC in the water of the ponds of the Tarom fish farm 5 times, and Krynychansky - 14 times. It is known that lead with significant exposure can cause bleeding in the digestive tract of fish, anemia, liver and kidney damage. In Tarom fishery, the maximum content of lead was found in scaly carp, which is 41,7% more than in white carp. A similar trend was observed in the Krynychany fish farm, but the content of this element in carp was only 2,2% higher. At the same time, the lead content of carp of the scaly Tarom farm was 34,4% higher in comparison with the same-age carp individuals grown in the Krynychany fish farm. The lead content in the body of young carp fish of the Dnieper fisheries was low. Cadmium is known to be more toxic than other heavy metals. In the young of silver carp Tarom fish farm cadmium concentration was higher by 14,3% than in carp. In fish of the Krynychany farm, on the contrary, the cadmium content was higher by 14.3% in scaly carp compared to silver carp. The biological role of manganese in fish is realized mainly through enzymes that are activated by this element. In Tarom farm the highest content of manganese was observed in silver carp, the concentration of manganese in scaly carp was 2,2 times less. In the Krynychany fish farm, on the other hand, the manganese content of scaly carp is 35% less than that of silver carp. Analyzing the data, it can be noted that the concentration of manganese in fish of Krynychany fish farm was higher compared to Tarom in 3,2 and 1,1 times in carp and silver carp, respectively. Copper is required for the synthesis of erythrocytes, in addition, it is part of liver proteins and a number of oxidative enzymes. In the young fish of both fish farms, the maximum copper content was observed in carp, it exceeded the content of this metal in silver carp by 1,3 and 2,1 times in Tarom and Krynychany farms, respectively. At the same time, the concentration of copper in this year's Tarom farm exceeded this indicator in the fish of the Krynychany fish farm by 1,5 and 2,3 times for carp and silver carp, respectively. The biological role of iron is mainly related to the function of iron-containing proteins. In young fish of Tarom fishery, the maximum concentration of iron ions was observed in silver carp and was 47,8% higher compared to carp. In the Krynychany fishery, on the other hand, a larger amount of iron was concentrated in the carp's body and was 1.9 times higher than in the silver carp of the same reservoir. The highest level of iron among the same-age fish of both fish farms was found in the young silverfish of Tarom farm, which was 2,4 times higher than the level of iron in silverfish of Krynychany fishery. The iron content in the young scaly carp of the Tarom fish farm was 21,5% higher than in the carp of the Krynychany farm. The importance of zinc for the body of fish is due to its participation in the regulation of many metabolic components in zinc-containing enzymes. In Tarom fish farm the highest content of zinc was found in carp, which is 2,4 times more than in silver carp. In Krynychany fish farm the highest concentration of zinc was found in silver carp, it was 18,6% higher than the concentration of zinc in carp. The highest level of zinc content among the studied fish farms was observed in the scaly carp of the Tarom farm and was 2,4 times higher than in the same carp of the Krynychany fish farm. The content of zinc in the carcass of silver carp of the Krynychany farm was higher by 19,6% in comparison with the one-year-old individuals of the Tarom fish farm. Thus, in the body of young fish of the studied fish farms actively accumulated such essential elements as Fe and Zn, which are necessary for normal growth and development of the organism. The minimum content of heavy metals was set for Cd. This pattern is the norm for growing fish. Prospects for further research are related to the study of the effect of toxicants of different origins on the morphobiological parameters of carp fish, which determines the feasibility of their continuation with the use of fish of different ages raised in the Dnipropetrovsk region. In addition, the results obtained can contribute to effective scientific support for the development of aquaculture in the region.

Only few genes are known from insects that encode multiple neuropeptides, i.e., peptides that activate different receptors. Among those are the capa and pk genes, which differentiated within Hexapoda following gene duplication. In our study, we focus on the early stages of differentiation of these genes. Specifically: (1) What was the expression pattern of the ancestral capa/pk gene, i.e., prior to gene duplication? (2) What is the expression pattern of capa and pk in silverfish, whose ancestors diverged from Pterygota more than 400 mya? Our results suggest the location and projection of CAPA immunoreactive Va cells in abdominal ganglia (trunk ganglia in Remipedia) are a plesiomorphic trait that was already present in the ancestor of Remipedia and Hexapoda. General features of serial homology such as location of cells bodies, contralateral projection of primary neurites, and presumed peripheral peptide release from segmentally arranged neurohemal release sites could be observed in Remipedia and silverfish, but also in all Pterygota studied so far. Differences are mainly in the specific location of these peripheral release sites. This hypothetical basic pattern of capa/pk neurons underwent modifications in the anterior ganglia of the ventral nerve cord already in Remipedia. In silverfish, as in all Pterygota studied so far, pk expression in the CNS is apparently restricted to the gnathal ganglia, whereas capa expression is typical of abdominal Va cells. Thus, differentiation in the expression pattern of capa and pk genes occurred early in the evolution of Hexapoda; likely soon after the appearance of two separate genes.

The silverfish Neoasterolepisma foreli belongs to the family Lepismatidae within Zygentoma and is well known for the peculiar habit of living in strict association with ant nests (myrmecophily). In this study, we describe its mitochondrial genome, a circular molecule of 15,398 bp including the canonical 13 PCGs, 22 tRNAs, 2 rRNAs, as well as a 403 bp AT-rich region. A phylomitogenomic analysis of the new sequence, alongside basal hexapod mtDNAs, confirmed the monophyly of all orders, with some uncertainty over the position of the enigmatic Tricholepidion gertschi that would make Zygentoma paraphyletic. Neoasterolepisma foreli is recovered in a basal position within family Lepismatidae, at odd with our current understanding of the group that would, in turn, suggest a closer relationship with the genus Lepisma (Mendes, 1991).

Pest management strives to be an efficient, yet healthy and environmentally safe control method, and the use of poisoned bait often fulfils these criteria. In the present study, we show that bait with indoxacarb as the active ingredient is highly efficient for controlling Ctenolepisma longicaudata (Escherich, 1905) and two of its relatives, Lepisma saccharina (Linnaeus, 1758) and Ctenolepisma calva (Ritter, 1910). Applying small bait droplets (size ~10 mg) along the walls of several types of buildings, at no more than 0.5 to 1.0 g bait per 100 m2, was a cost-efficient and safe strategy for the knockdown and eradication of C. longicaudata. During field experiments, the demography changed from an initial mixture of different stages to total dominance of early instars preceding the population collapse. Poisonous bait outcompeted mass-trapping with sticky-traps and conventional insect spray treatment for the efficient control of C. longicaudata in apartments. Different droplet densities (1 vs. 0.5/m2) and active ingredients (indoxacarb vs. clothianidin) did not have different effects in field experiments. These results show that poisoned bait is a highly relevant tool for managing C. longicaudata and potentially against other silverfish infestations.

RESUMEN El desierto absoluto de Atacama, carente de vegetación, se extiende por 740 kilómetros de latitud en Chile. En este ecosistema, la presencia de vertebrados de baja movilidad hace suponer el desarrollo de capacidades adaptativas especiales y la presencia de interrelaciones ecosistémicas que han sido poco exploradas. En este contexto, realizamos un levantamiento de información en dos gradientes de 76 km cada una, donde estudiamos la distribución y densidad de reptiles y mamíferos. Por otra parte, utilizamos isotopos estables para explorar las relaciones tróficas de los reptiles que habitan en este ecosistema. Observamos que las poblaciones de reptiles y mamíferos son poco frecuentes y presentan bajas densidades. Del punto de vista trófico, los pececillos de plata pertenecientes al orden Zygentoma son una presa clave en la comunidad de reptiles, los que se sobreponen en el consumo de fuentes tróficas, pero difieren en su posición en la cadena trófica. La información es complementada con antecedentes de predación entre reptiles de este ecosistema extremo.

The long-tailed silverfish (Ctenolepisma longicaudata) has recently made its appearance and demonstrated a tremendous proliferation in Norway, where it is currently considered a major indoor nuisance pest in modern buildings. To reduce the risk of human pesticide exposure, several baits with indoxacarb, clothianidin, fipronil or imidacloprid as the active ingredient were investigated to provide knowledge regarding their potential for integrated pest management solutions. Primary and secondary poisoning, as well as the durability of baits, were experimentally evaluated in bioassays. Baits with indoxacarb, clothianidin and fipronil killed more than 90% of the experimental insects (primary poisoning) when presented in competition with food. Only indoxacarb produced high mortality when dead conspecifics were consumed (secondary poisoning) and resulted in more than 75% mortality. The efficacy of baits with indoxacarb against C. longicaudata was also found to be very long. Laboratory degraded baits were consumed and induced high levels of mortality for more than a month, and field degraded baits for more than 6 months. Adults and juveniles were equally affected in the experiments. Primary and secondary toxicity in combination with long durability and effects on both life stages tested suggest that the bait has high-level potential as a safe control strategy against the long-tailed silverfish if indoxacarb is used as the active ingredient.

Antarctic silverfish (Pleuragramma antarcticaBoulenger) are a keystone species in the Ross Sea. Silverfish eggs and larvae are abundant during spring amongst the sub-surface platelet ice in Terra Nova Bay. It is not known whether the eggs are spawned elsewhere and accumulate under the ice or whether there is mass migration of silverfish to coastal spawning sites in winter. To test the latter hypothesis, an upward-looking 67 kHz echo sounder was moored in Terra Nova Bay to observe potential silverfish migration. The echo sounder was deployed at 380 m in a seabed depth of 550 m and ran for 210 days from 15 May until 11 December 2015. Acoustic reflections consistent with silverfish were observed at depths of 230–380 m during 9–22 September. This timing is consistent with the presence of eggs typically observed in October. Adult silverfish were also detected with an echo sounder and camera deployed through the ice in McMurdo Sound on 10 November 2015. Juvenile silverfish, but not adults, were observed through the ice in Terra Nova Bay during 11–16 November 2017. This paper provides a proof of concept, showing that innovative use of acoustics may help fill important observation gaps in the life history of silverfish.

Purpose The paper focused onto the development of microcapsules by using two essential oils. It proposes the uses of eucalyptus oil and cedarwood oil as a natural insecticide. The purpose of this paper is to demonstrate the application of developed microcapsules to impart insect repellency on textile substrate. Design/methodology/approach The paper opted for an experimental study using two essential oils and gum in formations of microcapsules through a simple coaseravtion encapsulation technique. The developed solution was analyzed, including confirmation of size and structure through. Application of developed finish on substrate was also undertaken to prove better ability as repellent fabric. Findings The paper highlights useful invention of microencapsulated fabric developed with the combination of gum acacia and eucalyptus oil as core and shell material. The developed fabric has better ability to repel silverfish as compared to microencapsulated fabric developed with gum acacia (shell) and cedarwood oil (core). Research limitations/implications Due to the lack of time and less availability of essential oils, only two oils were used to test the insect repellent behavior. Practical implications This paper fulfills an identified need, it includes implications for the development of a very useful natural insecticide to repel silverfish (Lepisma saccharina) insect. This insect is a very common problem found in cloth wardrobes and bookshelves; it mainly attacks the fabric with cellulosic content and starch. Social implications Society will get major benefit of using these microencapsulated finished fabrics, which repel silverfish from their home and keep their clothing and books safe for longer period. The natural fragrance and medicinal benefits of these essential oils can never be ignored. Originality/value This study sets a new approach to repel insects like silverfish from the bookshelves and clothing wardrobes. A layer of insect repellent microencapsulated finished fabric can be added in these shelves and wardrobes. It is an eco-friendly approach of using natural essential oils instead of chemical insecticides.

The long-tailed silverfish Ctenolepisma longicaudatum (Lepismatidae: Zygentoma) is a nuisance problem in buildings and a major concern in museums, libraries and archives where it cause damage to historical and priceless items. We used laboratory bioassays and two field studies of infested buildings to evaluate spatial and temporal elements of a poisoned bait strategy. In both laboratory experiments and field studies, the efficiency of poisoned bait with indoxacarb as the active ingredient was significantly improved by placing many small bait droplets evenly distributed along all edges of the treated area compared to more clustered distributions. Extended duration of bait presence and removal of competing food sources improved the control effect significantly in the laboratory bioassays. Bait-treated populations also showed a significant decline in the number of eggs deposited and emergence of new nymphs. The study supports poisoned bait as an efficient and low risk approach against the long-tailed silverfish in which extended duration of bait presence, wide distribution of bait droplets in combination with sanitation was crucial for control in the infested premises.

The lockdowns that came with policies to reduce the spread of COVID-19 in 2020 required some 90% of museums and historic properties across the globe to be closed. Lowered visitor numbers and reduced staffing levels allowed a range of fauna to make their way indoors, bringing an increase in birds, rodents and insect pests. Silverfish are shy, so benefit from low occupancy in museums and present a potential vector for damage to books and paper. This study is the first to report changes in insect populations in museums and examines six years (2015–2020) trapping data for silverfish and similar insects (Lepismatidae): Lepisma saccharinum, Ctenolepisma calvum, Ctenolepisma longicaudatum and Ctenolepisma lineatum from: (i) the Technisches Museum Wien, (ii) Schonbrunn Palace, (iii) Hofburg Museum and a shorter record from (iv) Weltmuseum Wien. Analysis of the trap contents gives an impression that the number of insects caught had increased over time, but 2020 was distinctive and gave typically higher insect numbers during the COVID-19 lockdown compared to other years, especially for Lepisma saccharinum. Individual traps caught up to 100 silverfish in only a few weeks. Because silverfish usually need between four months to one year to become mature, we assume that it was increased activity during museum closure and not higher reproduction which led to higher numbers. The parts of the museums showing increased populations under lockdown were similar to the areas where they were more frequent in earlier years. This means that such areas deserve continued monitoring even when the museum is closed. No damage to paper objects were reported in the museums investigated.

The common silverfish, Lepisma saccharina, is a well-known stored-product insect worldwide, which were obtained from China. The complete mitochondrial genome (GenBank: MT108230) consists of a circu...

DOI : 10.5152/actavet.2019.19015 The Bandirma district of Balikesir province has an important place in terms of production and export of aquatic and frozen fish products. Silverfish (Atherina boyeri Risso, 1810) has high protein quality (protein content >70%) and low price. It constitutes an important alternative source of raw material for economic fish meal production. Fresh silverfish exported to the European countries in recent years is demanded in two different product forms: Frozen and breaded frozen. In this study, the production of frozen silverfish was carried out in a business that produced aquaculture products for a considerable level of export in Bandirma. The production flow diagram, in accordance with TS EN ISO 22000 Food Safety Management System and British Retail Consortium Standard, was defined to obtain a safe product in accordance with customer expectations and needs. Hazard analysis was carried out by analyzing each step using decision tree. In this way, potential hazards and the precautions to be taken to prevent them, critical control points, and critical limits belonging to these points have been set forth. Cite this article as : Gunsen, U., Eseceli, H., Atan, R.M., 2019. Determination of Critical Control Points and Potential Hazard Analysis in the Production of Frozen Silverfish (Atherina boyeri Risso, 1810). Acta Vet Eurasia 45, 80-90.

The insect odorant receptor (Or) gene family is among the largest multigene families in insect genomes, but its evolutionary origin and mode of expansion is still a matter of debate. We performed transcriptomic surveys of two wingless insect species, the silverfishLepisma saccharinaandTricholepidion gertschi, and identified multiple Or gene family members in both species. A phylogenetic analysis suggests that the silverfish Ors do not fall into the clade comprised of more derived flying insect ligand-binding Ors, but, along with bristletail, firebrat and some mayfly Ors, are consistently resolved as a distinct set of genes that may constitute an evolutionary intermediate between gustatory receptors and the more derived Ors of flying insects. We propose to consider these “primitive Ors” separately from higher insect Ors until their cellular expression patterns and function are resolved and suggest a multistep evolutionary scenario ultimately leading to the highly sensitive, rapidly evolving and physiologically diverse Or gene family observed in higher insects.

Insect Mouthparts / Krenn, Harald W. (Editor) ; Cham : Springer International Publishing, 2019, Chapter 6 ; ISSN: 2523-3904=2523-3912 ; ISBN: 978-3-030-29653-7=978-3-030-29654-4 ; doi:10.1007/978-3-030-29654-4; Cham : Springer International Publishing, Zoological Monographs 5, 175 - 202 (2019). doi:10.1007/978-3-030-29654-4_6, Insects show a plethora of different mandible shapes. It was advocated that these mandible shapes are mainly a function of different feeding habits. This hypothesis was tested on a larger sampling of non-holometabolan biting–chewing insects with additional tests to understand the interplay of mandible function, feeding guild, and phylogeny. The results show that at the studied systematic level, variation in mandible biting–chewing effectivity is regulated to a large extent by phylogenetic history and the configuration of the mandible joints rather than the food preference of a given taxon. Additionally, lineages with multiple mandibular joints such as primary wingless hexapods show a wider functional space occupation of mandibular effectivity than dicondylic insects (= silverfish + winged insects) at significantly different evolutionary rates. The evolution and occupation of a comparably narrow functional performance space of dicondylic insects is surprising given the low effectivity values of this food uptake solution. Possible reasons for this relative evolutionary “stasis” are discussed., Published by Springer International Publishing, Cham

The Ross Sea is home to about a third of the world population of Adelie penguins ( Pygoscelis adeliae ). Between 2001 and 2013 the number of breeding pairs of Adelie penguins at colonies in the southwestern Ross Sea more than doubled. It has been suggested that this increase was caused by the fishery for Antarctic toothfish ( Dissostichus mawsoni ) leading to mesopredator release of Antarctic silverfish ( Pleuragramma antarctica ), a shared prey of toothfish and Adelie penguins. Cases of mesopredator release in marine systems have been widely reported, but limited information on marine predators often hinders quantitative investigation of these changes. The present study has brought together information from multiple models to estimate the biomass of silverfish that could be released from predation through the effects of the toothfish fishery. New diet data for toothfish are presented which show that Antarctic toothfish and Adelie penguins do not have significantly overlapping diets in the southwestern Ross Sea. The mass of silverfish released from predation due to the effects of fishing was estimated to be 128 tonnes wet-weight per year (tWW/y; 5th–95th estimation interval of 46–358 tWW/y) in 2013, equivalent to less than 2% of the biomass of silverfish estimated to be consumed annually by Adelie penguins. Even if toothfish consumed only silverfish, the predicted predation release effect would still not be sufficient to explain the observed increase in the number of Adelie penguins in the southern Ross Sea. The results of the modelling are hence inconsistent with predation release of silverfish due to the toothfish fishery being responsible for recent increases in the number of Adelie penguins breeding in the southwestern Ross Sea.

A number of changes have taken place in the higher classification of southern African insects since the last time it was documented in full (Scholtz & Holm 1985) and there is currently no comprehensive modern classification of higher insect taxa available for the region. Since 1985 a new order has been discovered in the region (Mantophasmatodea; Klass et al. 2002) and there have been various rearrangements between closely-related groups that have resulted in orders being combined (Blattodea and Isoptera into Blattodea; Inward et al. 2007; Psocoptera and Phthiraptera into Psocodea; Grimaldi & Engel 2005) while others have been subsumed in larger groups (Hemimerina in Dermaptera; Kocarek et al. 2013). Furthermore, until quite recently Thysanura was the ordinal name used for silverfish or fishmoths but the group is now considered to beparaphyletic with Meinertellidae included; the latter has been moved to the Archaeognatha (Grimaldi & Engel 2005). Zygentoma was the suborder that included all other thysanurans so it became the default name for the order. Numerous major family-level changes in several large orders have also taken place; the most important being: Coleoptera - Beutel & Leschen 2005, but modified as in the in press revision of the book; Diptera - partially according to Anorim & Yeates 2006; also Kirk-Spriggs & Sinclair in press/in prep; Lepidoptera - based largely on Nieukerken et al. 2011; Hymenoptera - bees, Michener 2007, wasps, Pulawski 2012.

The digestive system of selected phytophagous insects has been examined as a potential prospecting resource for identification of novel cellulolytic enzymes with potential industrial applications. In contrast to other model species, however, limited detailed information is available that characterizes cellulolytic activity and systems in basal hexapod groups. As part of a screening effort to identify insects with highly active cellulolytic systems, we have for the first time, identified species of Zygentoma that displayed the highest relative cellulase activity levels when compared to all other tested insect groups under the experimental conditions, including model species for cellulolytic systems such as termite and cockroach species in Rhinotermitidae (formerly Isoptera) and Cryptocercidae (formerly Blattodea). The goal of the present study was to provide a morphohistological characterization of cellulose digestion and to identify highly active cellulase enzymes present in digestive fluids of Zygentoma species. Morphohistological characterization supported no relevant differences in the digestive system of firebrat (Thermobia domestica) and the gray silverfish (Ctenolepisma longicaudata). Quantitative and qualitative cellulase assays identified the foregut as the region with the highest levels of cellulase activity in both T. domestica and C. longicaudata. However, T. domestica was found to have higher endoglucanase, xylanase and pectinase activities compared to C. longicaudata. Using nano liquid chromatography coupled to tandem mass spectrometry (nanoLC/MS/MS) and a custom gut transcriptome we identified cellulolytic enzymes from digestive fluids of T. domestica. Among the identified enzymes we report putative endoglucanases matching to insect or arthropod enzymes and glucan endo-1,6-β-glucosidases matching bacterial enzymes. These findings support combined activities of endogenous and symbiont-derived plant cell wall degrading enzymes in lignocellulose digestion in Zygentoma and advance our understanding of cellulose digestion in a primitive insect group.

Silverfish is a common name used to refer to many species in the order Zygentoma. The Entomological Society of America designates the term silverfish as the official common name to only one species, however: Lepisma saccharina Linnaeus. Lepisma saccharina is a pest in urban settings. It is a voracious feeder on materials high in starches, glue, and cellulose such as paper. Lepisma saccharina is a common pest in libraries and museums where paper books and labels are abundant. It can also be found outdoors under rocks, leaf litter, in caves, and in ant nests. Includes: Introduction - Distribution - Description - Life Stages and Biology - Hosts - Economic Importance - Survey and Detection - Management - Selected References.https://edis.ifas.ufl.edu/in1211 Also published at http://entnemdept.ufl.edu/creatures/URBAN/silverfish.HTM

An integrative inventory of the amphipod scavenging fauna (Lysianassoidea), combining morphological identifications with DNA barcoding, is provided here for the Filchner area situated in the south-eastern Weddell Sea. Over 4400 lysianassoids were investigated for species richness and relative abundances, covering 20 different stations and using different sampling devices, including the southernmost baited traps deployed so far (76°S). High species richness was observed: 29 morphospecies of which 5 were new to science. Molecular species delimitation methods were carried out with 109 cytochrome c oxidase I gene (COI) sequences obtained during this study as well as sequences from specimens sampled in other Antarctic regions. These distance-based analyses (trees and the Automatic Barcode Gap Discovery method) indicated the presence of 42 lineages; for 4 species, several (cryptic) lineages were found. More than 96% of the lysianassoids collected with baited traps belonged to the species Orchomenella pinguides s. l. The diversity of the amphipod scavenger guild in this ice-bound ecosystem of the Weddell Sea is discussed in the light of bottom–up selective forces. In this southernmost part of the Weddell Sea, harbouring spawning and nursery grounds for silverfish and icefishes, abundant fish and mammalian food falls are likely to represent the major food for scavengers. Finally, the importance of biodiversity surveys in the context of the establishment of a marine protected area in this region (Weddell Sea MPA) is highlighted and how future studies can contribute to a better understanding the ecological role of scavengers in this system is discussed.

Smith, Graeme B. (2015): New Silverfish Taxa from Queensland (Zygentoma: Lepismatidae). Records of the Australian Museum 67 (3): 67-81, DOI: 10.3853/j.2201-4349.67.2015.1641, URL: http://dx.doi.org/10.3853/j.2201-4349.67.2015.1641

Results of entomological and thermo-hygrometric monitoring carried out at the Angelica Library in Rome are presented and discussed. Monitoring was carried out for a whole year, from April 2015 to March 2016. The purpose was to verify the possible presence of infestations of the stored goods within the building by pest species and to evaluate the possible correlation between environmental parameters found within the various areas examined and the density of the pest species found. Several pest insects were found in the library but only the beetles of the family Dermestidae can be regarded as particularly harmful and dangerous. This family was present with the genera Attagenus and Anthrenus. The presence and the frequency of other pest organisms (silverfish, booklice and isopods) can be kept under control by monitoring the environmental parameters. Psocottera were represented by the genera Liposcelis and Dorypteryx. More dangerous pest species such as anobiids, termites, cockroaches or rodents were not found in the library.

The nototheniid Pleuragramma antarctica, commonly known as the Antarctic silverfish, dominates the pelagic fish biomass in most regions of coastal Antarctica. In this chapter, we provide shipboard oxygen consumption and nitrogen excretion rates obtained from P. antarctica collected along the Western Antarctic Peninsula and, combining those data with results from previous studies, develop an age-dependent energy budget for the species. Routine oxygen consumption of P. antarctica fell in the midrange of values for notothenioids, with a mean of 0.057 ± 0.012 ml O2 g−1 h−1 (χ ± 95% CI). P. antarctica showed a mean ammonia-nitrogen excretion rate of 0.194 ± 0.042 μmol NH4-N g−1 h−1 (χ ± 95% CI). Based on current data, ingestion rates estimated in previous studies were sufficient to cover the metabolic requirements over the year classes 0–10. Metabolism stood out as the highest energy cost to the fish over the age intervals considered, initially commanding 89%, gradually declining to 67% of the annual energy costs as the fish aged from 0 to 10 years. Overall, the budget presented in the chapter shows good agreement between ingested and combusted energy, and supports the contention of a low-energy lifestyle for P. antarctica, but it also resembles that of other pelagic species in the high percentage of assimilated energy devoted to metabolism. It differs from more temperate coastal pelagic fishes in its large investment in reproduction and its pattern of slow steady growth throughout a relatively long lifespan.

Arthropods form an extensive phylum of the animal kingdom, comprising widely varying members such as insects, arachnids, chitin-exoskeleton “shellfish” (e.g., crabs, shrimp, and lobsters), and centipedes. In addition to worldwide common allergies to house dust mites or hymenoptera venom, other allergies may become important in certain areas and are attributed to three major sources of allergens: cockroaches, ticks, and storage mites. Other less common allergen sources include spiders, mosquitoes, horseflies, red chironomid (midge) larvae, silverfish, and ladybugs, as well as a variety of storage pests. At present, only extract-based test systems are available for the majority of allergens in IgE-based diagnostics. Molecular characterization of numerous individual allergens has already been carried out. However, these individual allergens are only available for a small number of sources (e.g., cockroaches and storage mites) in routine diagnostics. Particularly in the case of allergen sources with known high cross-reactivity, the use of marker allergens is believed to improve diagnostics. The currently known individual allergens of the abovementioned allergy triggers from the arthropod realm are summarized, and their potential use in allergy diagnostics is discussed.

Acoustic methods have the ability to detect and quantify distribution and abundance of Antarctic silverfish (Pleuragramma antarctica) across a range of spatial and temporal scales. The main advantage of acoustic surveys over traditional net-based sampling methods for silverfish is that the larger adult fish are unlikely to avoid the echosounder. Acoustic surveys also allow relatively wide coverage over the whole water column in a short time period because data are collected while the vessel is steaming at 8–10 knots. The key uncertainties, as with most acoustic surveys, are target identification and target strength. These uncertainties are compounded because silverfish do not have a gas-filled swim-bladder and so are a relatively weak acoustic target. Use of multi-frequency acoustic data helps discriminate silverfish from krill and other associated species, and broadband acoustics has considerable potential in this regard. Acoustic target strength has been derived from scattering models and in situ and ex situ measurements. Adult silverfish exhibit different scattering properties to post-larvae and juveniles. In the Ross Sea, adult silverfish are distributed widely over the shelf and tend to form layers at 100–400 m depth. Juvenile silverfish of 50–80 mm standard length occur shallower and were observed as a weak layer centred at about 80 m depth.

The Antarctic silverfish is a neutrally buoyant notothenioid fish that lives in resource-rich pelagic habitats through all life history stages. Given the ancestral benthic origin of notothenioids, the ability of this species to live in the water column required extensive evolutionary adjustments centered on buoyancy, a process referred to as secondary pelagization. Many of these adaptive changes are found in the silverfish skeleton, including partial or total reduction of bony elements, which reduces skeletal mass and body density. Other novel skeletal traits, such as lengthening of bones of the ethmoidal portion of the neurocranium and jaws, are related to foraging in the water column and planctophagia.

The evolution of two-jointed mandibles is considered to be a major step during the evolution of early insects enabling the exploration of new types of food. Two-jointed – or dicondylic – mandibles are believed to be a groundplan characteristic for winged insects and silverfish. Jumping bristletails are thought to possess mandibles with one joint and are the sistergroup of winged insects + silverfish. However, our knowledge of the cephalic morphology of bristletails is limited to data from a few species and thus fragmentary. We investigated the cephalic morphology of both families of bristletails, Meinertellidae and Machilidae. We focused on skeletal elements and the musculature and compared them with the corresponding structures found in silverfish and winged insects. Bristletails show a previously unknown coupling structure between the maxillary palps and the mandibles and an additional anterior articulation of the mandibles in the region of the anterior tentorial pits. The articulation can be homologised with the anterior articulation in silverfish and winged insects. Together with a description of the functional morphology of the mandible system of bristletails and a discussion of the homology of mandibular articulations and related characters, we provide conclusive evidence that bristletails are, in fact, dicondylic insects.

Anelpistina nubigena, new species (Insecta: Zygentoma: Nicoletiidae) is described from the ecotourism center of Las Nubes, in the Selva Lacandona rainforest of Chiapas, Mexico. Sequencing of 16S rRNA of specimens collected from the area revealed that at least one additional sympatric species of Anelpistina inhabits this same locality.

Arthropods form a broad phylum within the animal kingdom, comprising widely varying members such as insects, arachnids, crabs and centipedes. In addition to common allergies to house dust mites or hymenoptera venom, there are also rarer allergies that can be attributed to three major sources of allergens: cockroaches, ticks and storage mites. Other less known allergen sources include spiders, mosquitos, horseflies, red chironomid larvae, silverfish and ladybugs, as well as a variety of storage pests. At present, only extract-based test systems are available for the majority of allergens in IgE-based diagnostics. Molecular characterisation of numerous individual allergens has already been carried out. However, these individual allergens are only available for a small number of allergen sources (e. g. cockroaches and storage mites) in routine diagnostics. Particularly in the case of allergen sources with known high cross-reactivity, the use of marker allergens is believed to improve diagnostics. The currently known individual allergens of the above-mentioned allergy triggers from the arthropod realm are summarized and their potential use in allergy diagnostics discussed.

The warming trend in the northern part of the Western Antarctic Peninsula (WAP) has led to a decrease in perennial and summer sea ice, an increase in heat content over the shelf, and lower phytoplankton biomass, which could affect the prey quality of krill and fish that are uti- lized by apex predators. We compared prey quality metrics, including elemental (C, N) content; total, neutral, and polar lipid content; and energy densities of known penguin prey items includ- ing krill (Euphausia superba, Thysanoessa macrura, and E. crystallorophias) and fish (silverfish Pleuragramma antarcticum and the myctophid Electrona antarctica) along the WAP latitudinal gradient each January from 2009 to 2011. E. antarctica had the highest prey quality in terms of lipid content and energy density, followed by T. macrura and P. antarcticum, then E. crystal- lorophias and E. superba. For all species, variations in C and N content were most strongly corre- lated with the animals' neutral lipid content, in that animals with the larger neutral lipid stores had significantly higher C and lower N content. Across all sexes and maturity stages, E. superba in the southern study region had ca. 20% higher total lipid content than E. superba in the north, and a stepwise multiple linear regression analysis showed that latitude, sexual differences, and upper water column temperatures best explained this regional difference in lipid content. This regional variability in E. superba prey quality could affect the ability of apex predators that rely on E. superba to meet their energetic demands, and should be considered in future modeling efforts.

Nutrient self-selection represents an important behaviour that has been measured across many taxa. Despite the amount of research on this phenomenon, few studies report the evaluation of the effects of environmental variables such as temperature on nutrient selection by animals. In the present study, the nutrient selections of the silverfish Lepisma saccharina L. are measured across a range of temperatures (10, 15, 20, 25, 30 and 35 °C) using feeding arenas with three nutrient choices: carbohydrate (sucrose), protein (casein) and fat (lard). An overall preference for carbohydrates is shown across the range of temperatures, followed by protein, and then fat. However, the proportional consumption of each dietary component changes with temperature; the proportional carbohydrate consumption decreases dramatically with increasing temperature (>94% of the diet at 15 °C but

We revise the type material of the enigmatic fossil insect Carbotriplura kukalovae Kluge, 1996 from the Pennsylvanian of the Czech Republic. Multiple errors in the original description are documented and corrected. C. kukalovae is regarded as a possible transitional fossil link between Zygentoma and Pterygota. Carbotriplurida is therefore elevated to ordinal rank and considered as putative fossil sister group of Pterygota. The paranotal theory of the origin of insect wings and the parachute theory of origin of insect flight are briefly discussed and further corroborated. Testajapyx thomasi from the Pennsylvanian of Mazon Creek is tentatively considered as Dermaptera rather than Diplura.

We have recently shown that firebrats, Thermobia domestica (Packard) (Thysanura: Lepismatidae), carry, and deposit with their faeces, the symbiotic bacterium Enterobacter cloacae (Jordan 1890) Hormaeche and Edwards 1960 (Enterobacteriaceae) and the symbiotic fungus Mycotypha microspora Fenner, 1932 (Mycotyphaceae), and that these microbes induce arrestment behaviour and aggregation of firebrats. Here, we tested whether giant silverfish, Ctenolepisma longicaudata Escherich (Thysanura: Lepismatidae), and common silverfish, Lepisma saccharina (Linnaeus) (Thysanura: Lepismatidae), also arrest in response to these two microbes. In dual-choice bioassays, E. cloacae arrested firebrats but not giant silverfish or common silverfish, whereas M. microspora arrested firebrats and giant silverfish but not common silverfish. As close relatives, firebrats and giant silverfish have similar microclimate and nutrient requirements and may use M. microspora as the same aggregation cue when they aggregate in hot and humid microclimates where M. microspora proliferates and breaks down cellulose. As a more distant relative to firebrats and giant silverfish, common silverfish seem to require a different as yet unknown aggregation cue or signal, possibly one that is indicative of the type of microclimate (room temperature; high humidity) they prefer.

Trace fossils of basal, apterygote (wingless) insects from the Pennsylvanian-aged Rhode Island Formation of southeastern New England include the body imprint Tonganoxichnus buildexensis and the trackways Mitchellichnus cf. ferrydenensis, Siskemia elegans, Stiallia pilosa, and Stiaria intermedia. Trackways with double and triple medial impressions (S. elegans and M. ferrydenensis) are rare among trace fossils attributed to such insects. To determine how these unusual trackway morphologies were produced, and why they are so rare, experiments were conducted over a range of media (5sedimentary substrates) with modern archaeognathans (jumping bristletails) and thysanurans (silverfish). Our experimental results suggest that archaeognathans produced the fossil body imprints, as well as trackways exhibiting opposite symmetry, but cannot rule out thysanurans for trackways exhibiting alternate symmetry. The results also show that a variety of appendages leave medial impressions. The rarity of fossil trackways with more than one medial impression results from the low mass of the animal and the delicate nature of the appendages making such structures, coupled with behavior (jumping and landing) and media properties (saturation and cohesiveness). The production of different numbers of medial impressions by a single archaeognathan species suggests that fossils should show similar variety, albeit in rare cases, and that the named ichnotaxa are likely derived from a single biological taxon. Finally, the experimental work provides new insights into the production and preservation in Stiallia and Tonganoxichnus.

Smith, Graeme B. (2016): On some Silverfish Taxa from Tasmania (Zygentoma: Lepismatidae and Nicoletiidae). Records of the Australian Museum 68 (2): 45-80, DOI: 10.3853/j.2201-4349.68.2016.1652, URL: http://dx.doi.org/10.3853/j.2201-4349.68.2016.1652

A new species of myrmecophilous Atelurinae silverfish, which is considered to represent a new genus, is described from Peninsular Malaysia where it was collected in emigration columns of the predacious army-ant Leptogenys distinguenda (Formicidae: Ponerinae). The new genus is compared with those silverfish species whose praetarsus is devoid of empodium as well as with all the seventeen Atelurinae known from the Oriental Region. All previously described Atelurinae from Malaysia are known as strictly termitophilous and share the existence of complete praetarsus (2 claws plus one smaller unguiform empodium). (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Air pollution has been found to have direct and indirect effects on forest passerines, but there is very little information on the effects of emissions from the pulp and paper industry. This long-term (7 y) study compares breeding parameters of Great tits in industrial and rural sites in maritime pine forests on the west coast of Portugal. We found that Great tits bred earlier, laid more eggs, and produced more fledglings in the industrial area, where we also found a higher biomass of caterpillars, an important food source for tits. There were also differences in ground arthropod numbers, the industrial area having more beetles and millipedes and the rural area more spiders and silverfish. Our results suggest that there are no direct toxic effects of emissions from the paper industry on the study species. However, invertebrate food availability is clearly related to pollution levels, which indirectly affect the breeding performance of the Great tit. Il est connu que la pollution atmosphérique a des effets directs et indirects sur les passereaux forestiers, mais il existe très peu d’information sur les effets des émissions polluantes de l’industrie des pâtes et papiers. Cette étude à long terme (7 ans) a comparé les paramètres de reproduction de mésanges charbonnières dans 2 pinèdes maritimes, l’une située dans un secteur industriel et l’autre dans un secteur rural, sur la côte ouest du Portugal. Nous avons observé que les mésanges charbonnières s’accouplaient plus tôt, pondaient plus d’oeufs et produisaient plus de jeunes dans les sites industriels, où nous avons également observé une plus grande biomasse de chenilles, une importante source de nourriture pour les mésanges. Il y avait aussi des différences dans les quantités d’arthropodes terrestres, les sites industriels ayant plus de coléoptères et de millipèdes et les sites ruraux plus d’araignées et de lépismes argentés. Nos résultats suggèrent qu’il n’y a pas d’effet toxique direct des émissions de l’industrie des pâtes et papiers sur l’espèce à l’étude. Cependant, la disponibilité des invertébrés est reliée de façon évidente au niveau de pollution, ce qui a un effet indirect sur la performance de reproduction de la mésange charbonnière. published

The Salangidae fish family includes the genera Neosalanx and Protosalanx, known as icefish or silverfish, which are imported frozen from China to Italy. The variable morphological characteristics and the small size make their particular species extremely difficult to identify. As a consequence it is not feasible to verify the precise identity of the product on the market. This means that Chinese fish can be used to fraudulently replace some much more expensive Italian species, which are similar in shape and size. Ten specimens of Neosalanx taihuensis directly collected from Lake Taihu and two hundred specimens of icefish collected from forty markets (twenty-seven from Italy and thirteen from China) were examined by direct sequencing of a portion of mitochondrial DNA belonging to the cytochrome b (cytb) gene in order to identify them at a specie level and to investigate any potential mislabelling. A BLAST analysis of the obtained sequences identified 90% of market samples as N. taihuensis, which rose to 93% when only products collected in Italy were considered. A phylogenetic tree was also constructed and the high bootstrap values obtained further supported our findings. Our results are also in agreement with some reports by Chinese authors, who describe this species as the most exploited of the Salangidae family in China in terms of internal consumption and exports. Furthermore, these findings corroborate the documentation collected from all over Italy, which reports N. taihuensis as being the only regularly imported species of icefish. The other species of salangids identified were Neosalanx anderssoni and Protosalanx chinensis. Overall, 15% of samples collected on the Italian market were mislabelled, thus confirming the existence of commercial frauds. By verifying the presence of one main icefish species on the Italian market (N. taihuensis), this study has contributed in identifying a precise target for inexpensive and rapid molecular analytical methods aimed at detecting and preventing fraud involving icefish.

Antarctic silverfish (Pleuragramma antarcticum) is a key link between plankton and the community of top predators in the shelf waters of the Ross Sea. In spite of their abundance and important role in Antarctic food chains, very little is known of many ecological and biological aspects of this species. A combined trawl and acoustic survey of silverfish was carried out on the western Ross Sea shelf during the New Zealand International Polar Year Census of Antarctic Marine Life research voyage on R.V. Tangaroa in February–March 2008. Multi-frequency acoustic data (12, 38, 70, and 120 kHz) allowed discrimination of silverfish marks from those of krill and other associated species. Mark identification was achieved using targeted midwater trawls. Additional midwater and demersal trawls were carried out at randomly selected locations over the shelf as part of the core biodiversity survey. Silverfish were widely distributed over the Ross Sea shelf. Adult silverfish tended to form layers at 100–400 m depth and were sometimes present close to the bottom, where they were frequently caught in demersal trawls shallower than 500 m. A weak layer at about 80 m depth was associated with juvenile silverfish of 50–80 mm standard length. Acoustic backscatter strength from both silverfish and krill marks increased with increasing frequency (i.e., was highest at 120 kHz), which is characteristic of species without an air-filled swimbladder. Acoustic target strengths (TS) for silverfish at 12, 18, 38, 70, and 120 kHz were estimated from anatomically detailed scattering models based on computed tomography (CT) scans of frozen specimens. The relationship between TS and fish length at 38 kHz was sensitive to estimates of density and sound speed contrast within the fish, especially for small specimens (less than 110 mm SL). Our best estimate of the acoustic biomass of silverfish in the study area was 592 000 t (95% confidence interval 326 000–866 000 t). However, the biomass of juvenile silverfish was highly uncertain due to large differences between TS model results.