Gills de novo assembly reveals oxidative stress, unfolded protein, and immune response on red cusk-eel (Genypterus chilensis) under thermal stress.

The heat waves on the South Pacific coast could lead to thermal stress in native fish. The red cusk-eel (Genypterus chilensis) is relevant for Chilean artisanal fisheries and aquaculture diversification. This study examined the effect of high-temperature stress in the gills of G. chilensis in control (14 °C) and high-temperature stress (19 °C) conditions. High-temperature stress induces a significant increase in gills cortisol levels. Additionally, oxidative damage was observed in gills (protein carbonylation and lipoperoxidation). RNA-seq data was used to build the first transcriptome assembly of gills in this species (23,656 annotated transcripts). A total of 1138 down-regulated and 1531 up-regulated transcripts were observed in response to high-temperature stress in gills. The enrichment analysis showed immune response and replication enriched processes (on down-regulated transcripts), and processes related to the folding of proteins, endoplasmic reticulum, and transporter activity (on up-regulated transcripts). The present study showed how gills could be affected by high-temperature stress.

Studies on Neotropical crickets: A new Tusked Cricket genus (Orthoptera: Phalangopsidae) from Colombia.

Dentoluzara spatulatus n. gen. et n. sp., from the middle lands of the Colombian Andes, is described. This new phalangopsid cricket is distinguished by its asymmetrical mandibles with a basal prolongation in the left one, which is why it is recorded as the first Tusked Cricket. This rare morphological structure has only been observed in some species of anostostomatids and a couple of genera of tettigoniids, but never in crickets. Furthermore, D. spatulatus n. gen. et n. sp., has the ps. p2, from the male genitalia, spatula-shaped, deriving its specific epithet from there. Finally, the new genus peculiar mandibular morphology and the subfamily Luzarinaes taxonomy are commented and discussed.

Supplementary description and ontogenetic variability of Coryphaenoides affinis: rediscovery of the species after 145 years since its original description (Teleostei: Gadiformes: Macrouridae).

A large adult (138 mm head length) of the grenadier genus Coryphaenoides is described. It is identified as C. affinis hitherto known only from two juvenile type specimens collected by HMS Challenger off Uruguay in 1876. The diagnosis of the species is revised to include the discovery of considerable ontogenetic changes in squamation. Spinulation on the body scales are reduced or lost with size, while the armament of the head scales become amplified. The larger of the syntype specimens is designated as the lectotype. All three known specimens of C. affinis were collected in the southwestern Atlantic at depths between 3500 and 4000 m. A key for identification for the species of the subgenus Nematonurus is provided.

Plerocercoids of Adenocephalus pacificus in Argentine hakes: Broad distribution, low zoonotic risk.

Adenocephalus pacificus is a tapeworm parasitic of marine mammals and the main agent of human diphylobothriosis caused by consumption of raw or undercooked marine fishes, being considered as a reemerging disease. Despite having a broad distribution in marine mammals in both hemispheres, plerocercoid larvae in fish have only been reported in the Pacific Ocean, in Peruvian waters, from where most human cases are known. In Argentine waters larval stages of Diphyllobothriidae have been recorded in Merluccius hubbsi, a main fish resource mostly exported frozen, headed and gutted (H&G) or as fillets; therefore, the possible presence of A. pacificus in edible products, and the extent of the risk of parasitism for humans becomes of health and commercial relevance. With the aim of detecting and identifying potentially zoonotic diphyllobothriids and quantifying infection levels in viscera and fillets of hakes, 43 entire fish, 471 H&G, and 942 fillets obtained from research cruises in 2019 and 2021 from the southern Argentine Sea (44-53°S; 63-68°W) were examined by transillumination and under stereoscopic microscopy. Plerocercoids were recovered at low prevalence and mean abundance in entire fish (13.95 % and 0.35) and H&G fish (2.76 % and 0.03) but no larval worms were found adhered to musculature or peritoneum, furthermore, no larvae were found in the fillets. Larvae were genetically identified, based on sequences of the large subunit ribosomal RNA nuclear gene (lsrDNA) and the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene, as members of A. pacificus, representing the first report of this species in a fish host outside South American Pacific coasts. No spatial nor bathymetric patterns in parasite burdens were observed across sampling sites, but prevalence increased with fish size. The recorded low parasite burdens, the absence of infective stages in fillets and the fact that most products are commercialized deeply frozen, diminish the risk of parasitism for consumers to a minimum. However, the identification of this zoonotic agent and the assessment of its distribution in fish products are a first indispensable step for the design of efficient and suitable measures, such as freezing or cooking meet, to ensure the prevention of human infections.

Spatio-temporal patterns of the crustacean demersal fishery discard from the south Humboldt Current System, based on scientific observer program (2014-2019).

This study summarises six years of spatio-temporal patterns of the discarded demersal community fauna recorded by onboard scientific observer program for both artisanal and industrial crustacean fisheries between 2014 and 2019, from mesophotic to aphotic depths (96 to 650 m) along the southern Humboldt Current System (28-38°S). In this period, one cold and two warm climatic events were observed during the austral summer 2014, 2015-2016 (ENSO Godzilla), and 2016-2017 (coastal ENSO), respectively. Satellite information showed that Chlorophyll-a concentration varied seasonally and latitudinally, associated with upwelling centres, while equatorial wind stress decreased southward of 36°S. Discards were composed of 108 species, dominated by finfish and molluscs. The Chilean hake Merluccius gayi was dominant and ubiquitous (occurrence, 95% of 9104 hauls), being the most vulnerable species of the bycatch. Three assemblages were identified: assemblage 1 (~200 m deep), dominated by flounders Hippoglossina macrops and lemon crabs Platymera gaudichaudii, assemblage 2 (~260 m deep), dominated by squat lobsters Pleuroncodes monodon and Cervimunida johni and assemblage 3 (~320 m depth), dominated by grenadiers Coelorinchus aconcagua and cardinalfish Epigonus crassicaudus. These assemblages were segregated by depth, and varied by year, and geographic zone. The latter represented changes in the width of the continental shelf, increasing southward of 36°S. Alpha-diversity indexes (richness, Shannon, Simpson, and Pielou) also varied with depth and latitude, with higher diversity in deeper continental waters (>300 m), between 2018-2019. Finally, at a spatial scale of tens of kilometres, and a monthly basis, interannual variations of biodiversity occurred in the demersal community. Surface sea temperature, chlorophyll-a, or wind stress did not correlate with discarded demersal fauna diversity of the crustacean fishery operating along central Chile.

Mechanism study of the gel-forming ability of heat-induced gel from Peruvian hake (Merluccius gayi peruanus) surimi.

The commercial value of Peruvian hake (Merluccius gayi peruanus) meat is low because of its soft texture. This study investigated the major factor contributing to the gel-forming ability of Peruvian hake surimi by comparing the effects of endogenous protease activity and parasitic infection. Heat-induced gels could not be obtained at 50 °C-90 °C. Surimi with severe parasitic infection showed a stronger gel-forming ability. The endogenous protease activities were the main factor influencing the Peruvian hake meat proteolysis and contributed to the low gel-forming ability, rather than parasitic infection. Specifically, endogenous cysteine proteases played an essential role in protein degradation and low gel-forming ability. Moreover, endogenous transglutaminase was also shown to be involved in the gel-forming ability upon heating at 40 °C. These results suggested that Peruvian hake meat could be used as a raw material of frozen surimi for fish gel by inhibiting the activity of endogenous proteases.

Health risk assessment and differential distribution of Arsenic and metals in organs of Urophycis brasiliensis a commercial fish from Southwestern Atlantic coast.

The concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn were analyzed in muscle, gills, and liver of Urophycis brasiliensis from two Southwestern Atlantic catch areas (Brazil and Argentina). Additionally, the health risk of general and fishermen populations through fish consumption was estimated. The gills showed the highest concentrations of most of the elements, followed by the liver. With the exception of As, the muscle was the organ with the lowest concentrations of most elements. Levels of arsenic in muscle of U. brasiliensis were exceeded the maximum permissible levels for human consumption recommended by local and international guidelines. The target hazard quotients (THQs) and the carcinogenic risk (CR) showed no risk for individual and all elements. These results highlight the importance of arsenic speciation in U. brasiliensis muscle in order to generate more reliable risk estimates.

Prevalence and molecular identification of zoonotic Anisakis and Pseudoterranova species in fish destined to human consumption in Chile.

Zoonotic larvae of the family Anisakidae found in several fish species represent a serious risk in public health since they may cause food-borne anisakidosis in humans. Chile has culinary preferences including eating raw fish in many traditional preparations. In the present study, a total of 180 fish specimens representing three different fish species, i.e., Chilean hake (Merluccius gayi), snoek (Thyrsites atun), and sea bream (Brama australis), were caught at central coast of Chile. Parasitological examination was performed on musculature and abdominal cavity for subsequent extraction and quantification of anisakid larvae. Estimation of infection parameters, such as prevalence, was performed indicating 100% (CI: 0.94-1.0) prevalence of anisakid L3 in Chilean hakes and snoeks. Moreover, sea breams reached a prevalence of 35% (CI: 0.23-0.48). Prevalence of anisakid larvae in muscle was also analyzed showing values of 18.6% (CI: 0.097-0.309) in Chilean hakes, 15% (CI: 0.07-0.26) in snoeks, and 1.7% (CI: 0-0.089) in sea breams. Meanwhile, prevalence of anisakid larvae in internal organs showed highest values for peritoneum (100% and 83.3%) for snoeks and Chilean hakes, respectively, for liver (96.7%) and gonads (86.6%) in Chilean hakes, and for intestine (98.3%) in snoeks. Molecular analysis of collected anisakid L3 unveiled presence of two potentially zoonotic nematode species, i.e., Pseudoterranova cattani and Anisakis pegreffii. P. cattani was found in Chilean hakes and snoeks being the first molecular host species report for Chilean snoeks. Besides, A. pegreffii was also identified in these species being the first molecular report on this regard. These findings are relevant for better understanding of epidemiology of anisakiasis in Chilean coasts and for public health issues considering potential risk of human population due to its culinary preferences in eating raw fish.

Structure of fish proteins as modified by salting procedures: A rheological and ultrastructural analysis of hake (Merluccius hubbsi) fillets.

Salting is a technique used for preserving fish meat and allows obtaining added value products. The salting process provokes several structure modifications, which in turns cause changes in the fish texture. Thus, the objective of this study was to investigate the effect of three salting procedures (dry salting [DS], mixed salting [MS] and brining [BS]) on the rheology and structure of Merluccius hubbsi (Argentine hake). Rheological properties were evaluated using dynamic oscillatory and thermorheology tests, and the structure changes by scanning electron microscopy. DS samples showed the highest values of salt concentration referred to liquid phase (zNaCl ), while BS showed the lowest ones. In all cases, elastic (G') and loss (G″) modulus increased with salting time. G' values exceeded G″ values, indicating a predominant solid behavior. DS samples presented the greatest increase in rheological parameters (G', G″ and η*). Thermomechanical spectra allowed to identify an increase in denaturation temperature (Td) of proteins (myosin and actin) for DS and MS, and to a lesser extent for BS (Td = 46.7 ± 0.4°C, Td = 50.3 ± 0.8°C, Td = 58.8 ± 0.6°C and Td = 58.2 ± 0.9°C for fresh, BS, MS and DS, respectively). Ultrastructural images evidenced conformational changes on the myofibrillar proteins and the connective tissue (collagen). BS caused the least superficial damage to hake tissue. Based on the results, BS could be the method recommended for the industrial production of salted M. hubbsi. PRACTICAL APPLICATION: During salting of hake, variations in water and salt content have a significant effect on the myofibrillar and connective tissue proteins. The study of rheological properties and microstructure allows a better understanding of the conformational changes induced by the salting process. The least surface damage exhibited by brining fillets is consistent with the mass transfer mechanism that leads to the formation of a film on the muscle surface that dilutes the salt; for this reason, compared to dry and mixed salting, brining could be the method recommended for the industrial production of salted (>15% w/w) Merluccius hubbsi.

Digestive proteinases from the marine fish processing wastes of the South-West Atlantic Ocean: Their partial characterization and comparison.

Fish processing generates plenty of waste that is directly discarded in open-air dumps and water sources, or treated in the same way as urban solid waste, causing serious pollution problems. The waste represents a significant source of high-value bioproducts with potential applications in different industrial processes such as the production of feed, fertilizers, biodiesel and biogas, detergent additives and cosmetics. The objective of this study was to characterize and compare specific activities under different pH values and temperature conditions of acid and alkaline proteinases and viscera yield from the following fish species: Argentine hake Merluccius hubbsi, Brazilian flathead Percophis brasiliensis, Brazilian codling Urophycis brasiliensis and Stripped weakfish Cynoscion guatucupa. Individuals were fished off the coast of Mar del Plata (Argentina) by a commercial fleet and the viscera were immediately extracted and kept on ice until use. Stomach proteinases from four species had the highest activity at pH 2, with stability in the range of pH 2-4. The optimum pH was 11.5 from intestinal enzymes of C. guatucupa, M. hubbsi and P. brasiliensis and 9.5 from intestinal enzymes of U. brasiliensis. Alkaline proteinases from all species were highly stable in the range of 7-11.5. The optimum temperature of stomach proteinases from the four species studied were 30 and 50°C, with stability at 10 and 30°C during 150 min. The optimum temperature of intestinal enzymes from the tested species were 50°C with high stability at 10 and 30°C during 150 min. Alkaline proteinase from all species and acid proteinases from C. guatucupa were inactive at 70°C after 150 min, while there was a residual activity lower than 5% at 80°C on pre-incubated stomach enzymes of M.hubbsi, P. brasiliensis and U. brasiliensis after 5, 10 and 20 min, respectively. Digestive proteinases recovered in this study could be appropriate for technological usage, reducing manufacturing costs, obtaining revenue from fishery wastes, and contributing to the reduction of environmental pollution.

Who let the young-of-the-year (YOY) up? The pelagic habitat as a nursery and feeding ground area for the YOY Argentine hake Merluccius hubbsi Marini, 1933.

The young-of-the-year (YOY) Argentina hake Merluccius hubbsi remained at particular distances off the seabed at pelagic habitat, in a nursery area located in the San Jorge Gulf off south-western Atlantic. Older specimens were daylight distributed near the bottom in the demersal habitat. In this paper the authors show that the pelagic habitat is favourable for YOY hake compared to the surrounding demersal habitat by decreasing the probability of encounter with larger hake protecting the YOY against conspecific predation, and providing a better food supply. From 303 stomachs of pelagic YOY Argentine hake analysed (60-250 mm), 274 (90.43%) contained prey. Pelagic Argentine YOY hake fed almost exclusively on zooplanktonic crustaceans (Euphausia spp. and Themisto gaudichaudii). From 980 demersal specimens (14-82 cm), 572 (58.36%) contained prey, mainly the lobster krill Munida gregaria, followed by other hakes by cannibalism. The intensity of feeding was higher on pelagic layers. The allometric weight-length relationship revealed that the YOY Argentine hake find sufficient food in the pelagic habitat to live and develop, by increasing their relative body thickness. The cannibalism increases from close to zero when the YOY hake are c. 20 m off the seabed, to between 15% (cold season) and 20% (warm season) when they are 10 m off the seabed. These results suggest that the pelagic habitat is a feeding ground for YOY hake, and it is a favourable one compared to the surrounding demersal habitat by protecting the YOY from cannibalism. Pelagic YOY hakes were less abundant and more distant from the bottom during the cold season (14.3 m) than during warm one (11.4 m), probably because of natural mortality and progressive recruitment to demersal habits.

Avaliação da qualidade do pescado comercializado na região de Botucatu, São Paulo / Evaluation of the quality of fish marketed in the region of Botucatu, São Paulo / Evaluación de la calidad del pescado comercializado en la región de Botucatu-SP

O Regulamento de Inspeção Industrial e Sanitária de Produtos de Origem Animal (RIISPOA) estabelece padrões de qualidade para peixes destinados a consumo humano, garantindo um produto servido ao consumidor com inocuidade e segurança. O objetivo do presente trabalho foi avaliar a qualidade do pescado comercializado nos distritos de Ipaussu e Botucatu, São Paulo, mais precisamente da Tilápia do Nilo (Oreochromis niloticus) e da Merluza (Merluccius hubbsi), por meio de achados de necrópsia e análises físico-quimicas. Foram adquiridas 8 amostras de Tilápia e 3 amostras de Merluza provindas de uma piscicultura, eutanasiadas com gelo na propriedade, e encaminhadas ao Laboratório de análises do Instituto de Biotecnologia (IBTEC) da Universidade Estadual Paulista (UNESP), em Botucatu. As Tilápias foram submetidas à inspeção macroscópica por meio de observação externa e interna e os filés de Merluza foram submetidos à análises físico-quimicas para avalição do frescor. No exame externo a lesão mais frequente foi hemorragia de pele (50%), nadadeiras (50%), brânquias (25%) e cavidade oral (12.5%), enquanto que no exame interno, esplenomegalia (75%) e hemorragia renal (50%) prevaleceram. As análises físico-quimicas apresentaram alterações significativas nas bases voláteis totais (BVT), tornando o alimento impróprio para o consumo de acordo com a legislação vigente. As alterações observadas configuram perda da qualidade do pescado, deterioração e lesões sugestivas de doença zoonótica. O pescado comercializado nos distritos de Ipaussu e Botucatu não encontrava-se de acordo com os padrões de frescor exigidos para o consumo estabelecidos pela legislação brasileira.(AU)

The Regulamento de Inspeção Industrial e Sanitária de Produtos de Origem Animal (RIISPOA) establishes quality standards for fish intended for human consumption, ensuring a product served to the consumer with safety and innocuity. The objective of the present work was to evaluate the quality of fish commercialized in the districts of Ipaussu and Botucatu, São Paulo, more precisely the Tilapia do Nilo (Oreochromis niloticus) and the Merluza (Merluccius hubbsi), through necropsy findings and physical-chemical analysis. Eight Tilapia and three hake samples were acquired from a fish farm, euthanized on ice at the farm, and sent to the Laboratory of analysis of the Biotechnology Institute (IBTEC) of the Universidade Estadual Paulista (UNESP), in Botucatu-SP. The Tilapias were submitted to macroscopic inspection by means of external and internal observation and the Merluza fillets were submitted to physical-chemical analysis to evaluate the freshness. In the external examination the most frequent lesion was hemorrhage of skin (50%), fins (50%), gills (25%) and oral cavity (12.5%), while in the internal examination splenomegaly (75%) and kidney hemorrhage (50%) prevailed. The physical-chemical analysis showed significant alterations in the total volatile bases (TVB), making the food unfit for consumption according to current legislation. The observed alterations configure loss of quality of the fish, deterioration and lesions suggestive of zoonotic disease. The fish commercialized in the districts of Ipaussu and Botucatu did not meet the freshness standards required for consumption established by the Brazilian legislation.(AU)

El Reglamento de Inspección Industrial y Sanitaria de Productos de Origen Animal (RIISPOA) establece normas de calidad para el pescado destinado al consumo humano, garantizando un producto servido al consumidor con seguridad e inocuidad. El objetivo del presente trabajo fue evaluar la calidad de los peces comercializados en los distritos de Ipaussu y Botucatu, São Paulo, más precisamente la Tilapia do Nilo (Oreochromis niloticus) y la Merluza (Merluccius hubbsi), a través de los resultados de la necropsia y del análisis físico-químico. Ocho muestras de Tilapia y tres muestras de Merluza fueron adquiridas en una piscifactoría, eutanasiadas en hielo en la propiedad y enviadas al Laboratorio de análisis del Instituto de Biotecnología (IBTEC) de la Universidade Estadual Paulista (UNESP), Botucatu-SP. Las Tilapias fueron sometidas a inspección macroscópica mediante observación externa e interna y los filetes de Merluza fueron sometidos a análisis físico-químicos para evaluar la frescura. En el examen externo, la lesión más frecuente fue la hemorragia de la piel (50%), las aletas (50%), las branquias (25%) y la cavidad oral (12,5%), mientras que en el examen interno predominaron la esplenomegalia (75%) y la hemorragia renal (50%). El análisis físico-químico mostró alteraciones significativas en las bases volátiles totales (BTV), lo que hace que el alimento no sea apto para el consumo según la legislación vigente. Las alteraciones observadas configuran la pérdida de calidad del pescado, el deterioro y las lesiones sugestivas de enfermedad zoonótica. El pescado comercializado en los distritos de Ipaussu y Botucatu no cumplía con los estándares de frescura requeridos para el consumo establecidos por la legislación brasileña.(AU)

Morphological and biochemical approaches to assess the nutritional condition of the Argentine hake Merluccius hubbsi larvae from two different nursery areas.

The Argentine hake, Merluccius hubbsi, is one of the most important fishing species in the Argentine Sea due to its great abundance and high-quality meat. The study of the nutritional condition is widely used to determine the physiological state of the fish larvae and to estimate their survival possibilities. The larval nutritional condition reflects the environmental conditions to which they have been exposed and represents a useful instrument to determine favourable nursery areas. It also provides tools for the comprehensive management of a population subjected to fishing exploitation. This study aimed to determine potential differences in the nutritional condition of M. hubbsi larvae from the two fishing stocks (Northern and Southern) of the species. The authors assessed the nutritional condition of larvae captured during the 2012 main reproductive peak in the nursery areas of each population. Two different methodologies were applied: a morphometrical approach, by recording five morphometric variables, and a biochemical technique, employing the RNA/DNA index (RDs ) and its derived index of growth performance. The morphometrical indexes did not show differences in the larval condition between both stocks. Nonetheless, the RDs index did detect differences in the nutritional condition of larvae from different stocks. The RDs index of larvae in pre-flexion and flexion stages showed significant differences between stocks, indicating that these stages are more susceptible to starvation. The results suggest that the biochemical indexes prove to be more sensitive than the morphometric indexes to detect slight differences in hake larvae nutritional condition. The scope and limitations of these techniques for the analysis of the nutritional condition of larvae are discussed.

Trophic niche partitioning of five skate species of genus Bathyraja in northern and central Patagonia, Argentina.

Overexploitation of marine communities can lead to modifications in the structure of the food web and can force organisms like elasmobranchs to change their feeding habits. To evaluate the impact that fisheries have on food webs and on the interactions between species, it is necessary to describe and quantify the diet of the species involved and follow it through time. This study compares the diet of five skate species using the data obtained from the by-catch of the Argentine hake (Merluccius hubbsi) fishery in north and central Patagonia, Argentina. Diet composition was assessed by analysing the digestive tract contents and trophic overlapping between species of the genus Bathyraja: Bathyraja albomaculata, Bathyraja brachyurops, Bathyraja macloviana, Bathyraja magellanica and Bathyraja multispinis. A total of 184 stomachs were analysed. The diets of B. albomaculata and B. macloviana mainly comprised annelids, whereas that of B. brachyurops primarily comprised fish, including hake heads discarded by the fishery. The diets of B. magellanica and B. multispinis were largely based on crustaceans. Despite the morphological similarities and their shared preference for benthic habitats, no complete diet overlaps were found between the different species. These results suggest that these skate species have undergone a process of diet specialisation. This is a common feeding strategy that occurs to successfully eliminate competition when resources are limited, which corresponds to the conditions found in an environment being affected by the pressures of overfishing.

Predicting habitat use by the Argentine hake Merluccius hubbsi in a warmer world: inferences from the Middle Holocene.

Fish skeletal remains recovered from two archaeological sites dated in the Middle Holocene of Tierra del Fuego (Argentina) were analysed to describe habitat use patterns by hake in the past and predict changes in a warmer world. Mitochondrial DNA was successfully extracted and amplified from 42 out of 45 first vertebra from ancient hake and phylogenetic analysis assigned all haplotypes to Argentine hake (Merluccius hubbsi). According to osteometry, the Argentine hake recovered from the archaeological site were likely adults ranging 37.2-58.1 cm in standard length. C and N stable isotope analysis showed that currently Argentine hake use foraging grounds deeper than those of Patagonian blenny and pink cusk-eel. Argentine hake, however, had a much broader isotopic niche during the Middle Holocene, when a large part of the population foraged much shallower than contemporary pink cusk-eel. The overall evidence suggests the presence of large numbers of Argentine hake onshore Tierra del Fuego during the Middle Holocene, which allowed exploitation by hunter-gatherer-fisher groups devoid of fishing technology. Interestingly, average SST off Tierra del Fuego during the Middle Holocene was higher than currently (11 °C vs 7 °C) and matched SST in the current southernmost onshore spawning aggregations, at latitude 47 °S. This indicates that increasing SST resulting from global warming will likely result into an increased abundance of adult Argentine hake onshore Tierra del Fuego, as during the Middle Holocene. Furthermore, stable isotope ratios from mollusc shells confirmed a much higher marine primary productivity during the Middle Holocene off Tierra del Fuego.

Development of the digestive system of Argentine hake, Merluccius hubbsi, larvae.

The Argentine hake Merluccius hubbsi is an important fishery resource of the Southwestern Atlantic Ocean and it is also a potential species for cultivation. In this work, the digestive system development in field-caught hake larvae was studied using histological and histochemical approaches. The digestive tract of larvae was divided into: oropharyngeal cavity (OPC), esophagus, stomach (that develops in the preflexion stage), and intestine. The annexed digestive glands consisted of the liver and the exocrine pancreas. At the beginning of the preflexion stage, teeth were developed in the OPC. There were mucous cells in the esophagus secreting different glycoconjugates from hatching. The enterocytes in the posterior intestine exhibited supranuclear vesicles associated with protein absorption. Mucous cells were observed in the posterior intestine in the preflexion stage and, in the anterior region, ending the flexion stage. Each type of glycoconjugates has a specific role. Acidic mucins lubricate and protect from mechanical damage, sialomucines protect from bacterial infections and neutral mucins regulate the acidity of mucus secretion, protect against abrasion and participate in the formation of the chyme, indicating a pregastric digestion. The liver was present since hatching with pancreatic tissue inside and increased in size acquiring the typical structure with hepatocyte cords, sinusoids, vacuoles, and hepatic duct. The hepatocytes vacuolization increased with larval development. The pancreas became extra-hepatic, with basophilic acinar cells and acidophilic zymogen granules. Throughout the ontogeny, the increased structural and functional complexity of the digestive system reflected the transition to exogenous feeding and nutritional increasing needs.

Review of the Brazilian species of Physiculus (Gadiformes: Moridae), with description of a new species from Saint Peter and Saint Paul Archipelago, equatorial Atlantic.

Three valid species of the genus Physiculus are known from the Brazilian marinewaters. A fourth, new species, Physiculus cirm n. sp.., is described based on seventeen specimens collected in the surroundings of Saint Peter and Saint Paul Archipelago, equatorial Atlantic. A review of the Brazilian species of Physiculus is provided, as well as a key to the species of the genus reported from the Atlantic Ocean. The new species is distinguished from all its congeners, except P. cynodon and P. karrerae, by the large number of longitudinal series of scales (156-189 vs. 70-150). P. cynodon from the Northern Pacific has about 200 longitudinal series of scales, and it differs from the new species by the number of rays of the first dorsal fin (6-8 vs. 10 in P. cynodon), pectoral-fin rays (20-25 vs. 27 in P. cynodon), and the presence of an outer row of large canine teeth on upper and lower jaw. From P. karrerae, which has 134-160 longitudinal series of scales, the new species differs by the presence of scales on the tip of the snout and dorsal-fin membrane, and the number of pectoral-fin rays (20-25 vs. 24-27 in P. karrerae). [Zoobank URL: urn:lsid:zoobank.org:act:1AFBC251-2BB1-4479-98A4-307188EC5D66].

Does trawl fisheries affect the diet of fishes? A stable isotope analysis approach.

Trawling is the main fishing practice worldwide and its ecosystem effects have been raising concern over the past decades. Long-term impacts can be monitored through changes in the trophic structure, and several studies evaluated trophic level (TL) shifts in fish populations between trawled and untrawled environments. However, published results are contrasting. We performed a metanalysis integrating all available studies that evaluated TL shifts in fishes between trawled and untrawled environments and conducted a local study comparing several features of the trophic ecology in two species of fishes. According to the metanalysis, TL does not change significantly with trawling. In contrast, the local study showed higher TLs and broader isotopic niches in the trawled environment. Diet reconstruction indicated a potential consumption of hake, the main discard component, at the trawled environment. All the studies used in the metanalysis were conducted in the Northern Hemisphere, whereas the local study represents the first data available from the Southern Hemisphere. As industrial commercial fisheries in Argentina are relatively recent, it is possible that our data are capturing the initial stage of ecological changes induced by trawling, compared with the historical fisheries located at the Northern Hemisphere.

The fishery exploitation of acoupa weakfish off São Paulo coast, Southeastern Brazil / A exploração pesqueira da pescada-amarela na costa de São Paulo, Sudeste do Brasil

The Acoupa weakfish Cynoscion acoupa (Lacepède, 1801) is a large inshore sciaenid of commercial and social importance found along the entire Brazilian coast. In spite of this, there is few information on the species, both in terms of biological aspects and fishery yields, particularly off southeastern Brazil. Within this context, this study aimed to an evaluation of Acoupa weakfish fishery production off São Paulo coast (23°22–25°18S) based on publicly available statistical data collected between 1998 and 2016. Acoupa weakfish fishery in this State takes place on both industrial and artisanal scales, and employs at least 22 different fishing gears. The pair-trawling fishery was the most important Acoupa weakfish producer during the period surveyed, with a sharp decline in the catches from 2007 onward due to the establishment of Marine Protected Areas off São Paulo coast, which banned trawling in depths shallower than 26 meters. Acoupa weakfish yields were relatively low in São Paulo when compared with other demersal fishes exploited, despite the high retail prices commanded by the species in regional markets and restaurants.(AU)

A pescada-amarela Cynoscion acoupa (Lacepède, 1801) é um cianídeo demersal costeiro de grande porte que apresenta importância social e econômica ao longo de toda a costa brasileira. Entretanto, há pouca informação sobre a espécie em termos biológicos e pesqueiros, principalmente no sudeste do Brasil. Dentro desse contexto, o presente estudo procurou avaliar a produção pesqueira da espécie na costa de São Paulo (23°22–25°18S) a partir de dados estatísticos de domínio público coletados entre 1998 e 2016. A pescaria da pescada-amarela no estado ocorre em escala industrial e artesanal, e emprega pelo menos 22 tipos de artes de pesca. O arrasto de parelhas foi o mais importante produtor durante o período estudado, apresentando um declínio abrupto nos desembarques a partir de 2007, devido a implementação de Áreas Marinhas Protegidas na costa paulista, que baniu a pesca de arrasto em profundidades menores que 26 metros. Os desembarques de pescada-amarela são relativamente baixos em comparação a outros peixes demersais capturados apesar dos altos preços de varejo cobrados para a espécie nos mercados e restaurantes regionais.(AU)

Growth of the Brazilian codling, Urophycis mystacea, (Phycidae-gadiformes) of Southeastern Brazil / Crescimento da abrótea-de-profundidade, Urophycis mystacea, (Phycidae-Gadiformes) na região Sudeste do Brasil

The Brazilian codling Urophycis mystacea (Phycidae-Gadiformes) is a demersal-benthic species, present at the outer shelf and slope of Southeastern Brazil. Its stock has been declining since 2001, when it became a target species for the bottom trawling fleet, which went fishing between the outer shelf and the upper slope. In this study, we present results on the annual periodicity and deposition time of otolith rings, age, growth parameters and, relationships between otolith morphometric variables and age. Males were 1 to 6 years old, and females were 1 to 12 years old. The maximum likelihood ratio test proved that von Bertalanffy growth equations obtained for males and females were significantly different; respectively, Ct =419.33[1-exp-0.35(t-(-0.55))] and Ct=629.89[1-exp-0.17(t-(-0.89))]. The Potential Model presented the best fit for the relationship between the otolith morphometric variables and the fish age and its robustness, verified by the coefficient of determination values (R2). The otolith weight, followed by length, was the most adequate variables to estimate age.(AU)

A Abrótea-de-profundidade, Urophycis mystacea, é uma espécie demersal-bentônica, presente na plataforma externa e no talude da Região Sudeste-Sul do Brasil. Seu estoque vem diminuindo desde 2001, quando se tornou alvo da frota de arrasto de fundo, que passou a operar entre a plataforma externa e o talude superior. No presente estudo, investigamos o crescimento da espécie apresentando resultados sobre: periodicidade anual e época de formação dos anéis nos otólitos, idade e parâmetros de crescimento, além de relações entre variáveis morfométricas dos otólitos e idade. Foram encontrados machos com 1 a 6 anos e fêmeas com 1 a 12 anos de idade. A equação de crescimento de von Bertalanffy obtida para machos foi Ct = 419,33[1-exp-0,35(t-(-0,55))] e, para fêmeas, Ct = 629,89[1-exp-0,17(t-(-0,89))]. O teste da razão de máxima verossimilhança revelou diferenças significativas no crescimento entre sexos. A relação entre variáveis morfométricas dos otólitos e idade foi melhor representada pelo Modelo Potencial, e sua robustez, verificada através do valor do coeficiente de determinação (R2). O peso do otólito, seguido do comprimento, foram as mais adequadas para predizer a idade dos exemplares.(AU)