Feces and molting as microplastic sinks in a mangrove crab.

We exposed adult individuals of the sentinel mangrove crab Minuca rapax to waterborne microplastics (MP; 53-63 µm polyethylene spheres) in a long-term experiment (56 days). Weassessed 1) MP effects on growth, survival, and food intake. and 2) the MP tissue acumulation and its reduction of body burden through feces and molting. MP exposure did not affect growth and survival. The hepatopancreas accumulated more MP than the gills and muscle. Most of the ingested MP particles were released in the feces and molts, indicating a rapid passage through the digestive tract. MP impaired food intake of M. rapax, with unknown consequences to the local populations. These results provide insights on MP translocation mechanisms, its elimination and toxicity associated with MP.

Population structure and reproductive indicators of the surubim Pseudoplatystoma punctifer (Siluriformes, Pimelodidae) in the São Miguel River, Amazon basin, Brazil.

Fish is an important source of food and income for a significant portion of the Amazonian population, especially those who live along the rivers and lakes in the region. Pseudoplatystoma punctifer (Castelnau, 1855), known as surubim, is a species of Neotropical catfish widely exploited by fisheries and commercially valuable in the Guaporé River basin, Brazil. However, population dynamics are poorly known in the region. To understand the population structure and reproductive biology aspects of the surubim, monthly experimental fisheries were carried out in the São Miguel River, state of Rondônia, Brazil, between August 2020 and July 2021. The captured fish were weighed, and its gonads were removed and weighed for histological analyses (microscopic description) and classification of the maturation stages (macroscopic description). The collected gonads were fixed in 10% buffered formalin, dehydrated, cut into 4-µm-thick sections, and stained with hematoxylin and eosin. A total of 34 individuals were collected (20 females and 14 males), showing positive allometric growth and condition factor from 0.81 to 1.79 for females and males, respectively. Females were larger in size and weight than males. P. punctifer reaches its first maturation at an average length of 68.30 cm, indicating the importance of respecting the minimum capture size as an alternative to ensure the natural stocks of this fishery resource in the region. The results provide support for the establishment of public policies and actions for conservation, management, and regulation of fishing.

Growth type and relative condition factor as a function of the body shape of deep-water crustaceans in the Colombian Caribbean Sea.

Length-weight relationships (LWR) and relative condition factor were described for species of deep-water crustaceans caught with bottom trawls in a depth range between 150 and 535 m during August and December of 2009, and March and May of 2010 in the Colombian Caribbean Sea. A linear regression was performed using the logarithmically transformed data to calculate the a and b coefficients of the LWR for 22 crustacean species corresponding to 13 families and 19 genera and three types of crustaceans (shrimp, crab, lobster). Six crustacean species showed a maximum total length greater than that reported in SeaLifeBase: Garymunida longipes (77.00 mm), Eunephrops bairdii (220.00 mm), Metanephrops binghami (197.46 mm), Penaeopsis serrata (149.00 mm), Polycheles typhlops (196.27 mm) and Pleoticus robustus (240.00 mm). A total of 11 species (50.0%) exhibited isometric growth, five species (22.7%) negative allometric and six species (27.3%) positive allometric. This study shows the first estimates of LWR for 12 species of deep-water crustaceans in the Colombian Caribbean Sea. We demonstrate for the first time that the growth parameters (intercept and slope) of the LWR varying significantly as a function of the body shape of crabs, lobsters and shrimps in deep-water crustaceans.

Elemental composition of Talang Queenfish (Scomberoides commersonnianus Lacépède, 1801) in relation to body size and condition factor from Pakistan / Composição elementar de Talang Queenfish (Scomberoides commersonnianus Lacépède, 1801) em relação ao tamanho do corpo e fator de condição do Paquistão

Fish is thought to be the most appropriate for indication of toxicity in water. So, purpose of present study was to determine the concentrations of few metals (Na, K, Ca, Mg, Fe, Cd, Pb and Zn) in relation to the body size and condition factor in Scomberoides commersonnianus. A total of 73 samples of marine fish, S. commersonnianus with various sizes that ranged from 93.4-1180 g of body weight and total length 20.5-56.9cm were randomly collected from the Arabian Sea of Karachi Pakistan, for examination of elemental composition. The concentration of Calcium found maximum while Cadmium found minimum in S. commersonnianus. Concentrations of Zn showed highly significant (P<0.001) negative, while Na and Ca exhibited strong positive correlation with the fish size. Correlations of Pb, K and Mg were found least significant (P<0.05) with the wet weight and total length of S. commersonnianus. Whereas, Fe and Cd were remained insignificantly correlated (P>0.05) with the fish size. Condition factor showed highly significant correlation (P<0.001) with all studied metals except cadmium and lead which were found insignificantly correlated (P>0.05) with condition factor of S. commersonnianus.

O peixe é considerado o mais adequado para indicação de toxicidade na água. Assim, o objetivo do presente estudo foi determinar as concentrações de alguns metais (Na, K, Ca, Mg, Fe, Cd, Pb e Zn) em relação ao tamanho corporal e fator de condição em Scomberoides commersonnianus. Foi coletado um total de 73 amostras de peixes marinhos, S. commersonnianus, com tamanhos que variaram de 93,4 a 1.180 g de peso corporal e comprimento total de 20,5 a 56,9 cm, aleatoriamente do Mar Arábico de Karachi, Paquistão, para exame de composição elementar. A concentração de Ca foi máxima, enquanto a de Cd foi mínima em S. commersonnianus. As concentrações de Zn mostraram-se altamente significativas negativas (P < 0,001), enquanto Na e Ca apresentaram forte correlação positiva com o tamanho dos peixes. As correlações de Pb, K e Mg foram menos significativas (P < 0,05) com o peso úmido e o comprimento total de S. commersonnianus. Já o Fe e o Cd permaneceram pouco correlacionados (P > 0,05) com o tamanho dos peixes. O fator de condição apresentou correlação altamente significativa (P < 0,001) com todos os metais estudados, exceto Cd e Pb, que foram encontrados correlacionados insignificantemente (P > 0,05) com o fator de condição de S. commersonnianus.

Length-weight relationships of farmed major carps (Cattla cattla, Labeo rohita and Cirhinus mrigala) fed with different sources of protein in an intensive polyculture / Relações peso-comprimento de carpas principais (Catla catla, Labeo rohita e Cirrhinus mrigala) cultivadas e alimentadas a partir de diferentes fontes de proteína em uma policultura intensiva

The present findings provide information regarding the length-weight relationships (LWRs) of Indian major carps viz Cattla cattla, Labeo rohita and Cirhinus mrigala in an intensive polyculture system. Much work has been done in Pakistan with respect to fish LWRs, much of such work has been ignored. Carps were fed with twelve different formulated diets containing four different sources of protein i.e. fish meal (FM), all parts chicken meal (APCM), corn gluten (CGM) and soybean meal (SBM). Each type of protein is used at inclusion level of 25, 35 and 45% into the formulated diets to evaluate the minimum requirement of that ingredient for optimal growth of in-hand species. The values of slope "b" ranged from 2.20 to 4.90 for these species of carps which showed a strong healthy relationship among variables (level of protein and months).

Os achados do presente trabalho fornecem informações sobre as relações comprimento-peso (LWRs) das principais carpas indianas, como Catla catla, Labeo rohita e Cirrhinus mrigala, em um sistema de policultura intensivo. Foram realizados muitos trabalhos no Paquistão em relação ao peixe LWRs, entretanto, foram ignorados. As carpas foram alimentadas com doze dietas formuladas diferentes contendo quatro fontes diferentes de proteína, ou seja, farinha de peixe (FM), todas as partes de farinha de frango (APCM), glúten de milho (CGM) e farelo de soja (SBM). Cada tipo de proteína foi utilizado em nível de inclusão de 25, 35 e 45% nas dietas formuladas para avaliar a exigência mínima desse ingrediente para o crescimento ideal das espécies em mãos. Os valores da inclinação "b" variaram de 2,20 a 4,90 para essas espécies de carpas que mostraram uma forte relação saudável entre as variáveis ​​nível de proteína e mês.

Impact of commercial formulations of herbicides alone and in mixtures on the antioxidant system and body condition parameters in tadpoles of Rhinella icterica (Spix 1824).

Pesticide usage has increased over the last decades, leading to concerns regarding its effects on non-target organisms, especially amphibians. Tadpoles of Rhinella icterica were collected in a pesticide-free place, acclimated in the laboratory (21 days) and exposed (7 days) to three herbicides (20 µg/L atrazine (A); 250 µg/L glyphosate (G); 20 µg/L quinclorac (Q)) and their mixtures. Only 2% mortality was observed over the 28 days of the study. Despite this, significant variations were observed for markers of oxidative balance and body condition when comparing all experimental groups. K and Kn factor showed the lowest values in the group A+G+Q, as well as the activity levels of GST and SOD. In contrast to this, the CAT activity was higher in the same group (A+G+Q). The mixture of the three herbicides proved to be more harmful, which points to the need for more restrictive laws for the use of mixed herbicides.

Microplastics in commercial seafood: Pleoticus muelleri as a case study in an estuarine environment highly affected by human pressure (Southwestern Atlantic).

Plastic pollution in seafood has become a worldwide safety concern due to its possible harm to humans. This is the first study which has investigated the length-weight relationship, growth patterns and condition factor, together with the concentrations of microplastics (MPs) and mesoplastics (MesoPs) in Pleoticus muelleri from the Bahia Blanca Estuary (BBE), Argentina. Forty-nine individuals were collected from three sampling stations in the BBE, and each abdominal muscle with the gastrointestinal tract was analyzed. P. muelleri showed an isometric growth pattern (b = 3.0054) with values of K similar among the individuals collected (ranged between 0.80 and 0.91), considering them in good condition compared to other crustacean species around the world. 96% of shrimp presented transparent or black synthetic fibers as prevalent types, with an abundance average of (3.0 ± 2.90) MPs/g w. w. And (0.053 ± 0.16) MesoPs/g w. w. as well as a dominant size range of 0.5-1.5 mm, in accordance with recent studies in the same area. The linear regression analysis showed that K was independent of the concentration of MPs ingested by P. muelleri, with R2 ranging between 0.024 and 0.194 indicating that MPs contamination does not affect the nutritional condition of shrimp. SEM/EDX detected the presence of elements like C, O, K, and Mg, tissue residues and fractures on the surface of the analyzed fibers. FTIR confirmed different types of polymers in shrimp related to textile fabrics probably from untreated sewage discharges from nearby cities. The results of this research provide useful information for a better understanding of MPs contamination in seafood, suggesting P. muelleri as a suitable species for monitoring MPs in estuarine ecosystems. Likewise, more research is required to know the effects of MPs on food safety in humans.

What happens to Hoplias malabaricus fed on live prey (Astyanax altiparanae) previously exposed to copper? A multiple biomarker approach.

Copper waterborne toxicity is well understood in aquatic organisms. However, the dietary copper effects are much less known, especially in tropical fish. The toxicity of copper via the trophic route could be influenced by the composition of the food, and diets naturally impregnated with copper seem to have greater toxicity at lower concentrations than artificially impregnated ones. Thus, our objective was to investigate the effects of copper on juveniles of the Neotropical fish Hoplias malabaricus fed on live prey (Astyanax altiparanae) previously exposed to the metal (20 µg L - 1) for 96 h. The prey fish were given to H. malabaricus every 96 h, totaling 10 doses at the end of the experiment. Thus, after 40 days fish were killed and tissues were sampled. Blood showed to be the only tissue in which copper accumulated. Anemia was found and there was damage to the DNA of erythrocytes. Furthermore, ionic imbalances were observed in plasma. There was an increase in the concentration of Na+ and Cl- and a decrease in Ca2+, which were associated with increased copper uptake in the gastrointestinal tract of fish fed on copper exposed prey. All the antioxidant enzymes evaluated in the gills showed decreased activity compared to the control group. Copper seems to have interfered in the energy metabolism of H. malabaricus, since a lower condition factor and feed conversion efficiency rate were observed in fish fed with copper diet. The present study confirms the trophic route as an important copper toxicity pathway for H. malabaricus and reinforces the idea that metal toxicity can be increased when it is naturally impregnated in the prey tissues, even if the prey has been exposed to the metal only for a short period of time.

Relative condition factor and predictive model for the presence of the invasive snail Achatina (Lissachatina) fulica in Sergipe, Northeast Brazil / Fator de condição relativo e modelo preditivo para a presença do caracol invasor Achatina (Lissachatina) fulica em Sergipe, Nordeste do Brasil

Abstract: Achatina fulica is among the world's 100 most impactive invasive species, and is now found in almost all Brazilian states, including Sergipe. This exotic snail is known to have negative impacts, not only on the environment, due primarily to the rapid growth of its populations, but also on public health, given that it is an intermediate host of nematodes that cause zoonotic diseases. However, relatively little is known of the development of this snail, including its relative condition factor. We investigated the occurrence of A. fulica in 24 municipalities distributed in the eight subregions of the state of Sergipe in the dry and rainy season. Furthermore, we present here a predictive model for the occurrence of A. fulica based on the variation in climate and soil chemistry. This snail was more frequent on soils with a pH of 6.5-7.5. A negative correlation was found between the growth of A. fulica and the soil pH, then, the more acidic the soil, the more allometric the growth of A. fulica. The relative condition factor indicated differences in the development pattern of A. fulica among the eight subregions. The influence of rain in increasing the frequency of A. fulica showed a significant correlation. As well, higher temperatures influenced the resting behavior of A. fulica. The mathematical model used to identify the potential presence of A. fulica presented a high degree of agreement. This is the first ecological study of A. fulica to verify the association between the body mass-length relationship and the relative condition factor, and the results indicate that the development of this exotic land snail in Sergipe is influenced by climatic factors and principally, the soil pH. The predictive mathematical model provides valuable insights into the biotic and abiotic factors associated with the presence of A. fulica, and the influence of climatic variables and the chemical parameters of the soil on the occurrence of this species. These findings provide important guidelines for the development of measures for the control of A. fulica populations, which will contribute to both public and environment health.

Resumo: Achatina fulica está entre as 100 das piores espécies invasoras em todo o mundo, e no Brasil está presente em quase todos os estados, incluindo Sergipe. Este caracol exótico é conhecido por ter impactos negativos, não só no meio ambiente, devido principalmente ao rápido crescimento de suas populações, mas também na saúde pública, uma vez que é um hospedeiro intermediário de nematodeos causadores de doenças zoonóticas. No entanto, pouco se sabe a respeito do desenvolvimento dessa espécie, incluindo o fator de condição relativo. Investigamos a ocorrência de A. fulica em 24 municípios distribuídos nos oito territórios do estado de Sergipe no período seco e chuvoso. Além disso, apresentamos aqui um modelo preditivo para a ocorrência de A. fulica baseado na variação do clima e da química do solo. Esse caracol é mais frequente no solo com pH de 6,5 à 7,5, sendo esse padrão ideal para o crescimento isométrico. O crescimento alométrico de A. fulica apresentou correlação negativa com o pH do solo, quanto mais ácido for o solo, maior será o crescimento de A. fulica. O fator de condição de A. fulica, apresentou diferença no desenvolvimento nos oito Territórios. A influência da chuva na frequência de A. fulica apresentou correlação significativa. Além disso, temperaturas mais elevadas influenciaram no comportamento de repouso de A. fulica. O modelo matemático para identificar a possível presença de A. fulica apresentou uma concordância forte. Este é o primeiro estudo ecológico de A. fulica a verificar a associação entre a relação massa-comprimento e o fator de condição relativo, sendo possível evidenciar que essa espécie exótica em Sergipe sofre alterações no desenvolvimento, por fatores climáticos e principalmente pelo pH do solo. O modelo matemático preditivo fornece informações valiosas sobre os fatores bióticos e abióticos associados à presença de A. fulica e a influência de variáveis climáticas e dos parâmetros químicos do solo na ocorrência desta espécie. Esses achados fornecem importantes diretrizes para o desenvolvimento de medidas de controle de populações de A. fulica, que poderão contribuir para a saúde pública e ambiental.

Life-History traits of Hollandichthys multifascitus (Eigenmann & Norris, 1900) (Characiformes: Characidae) in coastal Atlantic Forest blackwater streams from Southeastern Brazil

Ecological and life history traits have been used to understand the basic ecology of fishes. This study aimed to examine the existence of plasticity in life history traits of populations of Hollandichthys multifasciatus in ten blackwater streams. This is an inseminating Characidae, endemic to the Atlantic coastal drainages of Brazil. Different aspects of the life-history of the species, such as mean length, sex ratio, absolute and relative fecundity, gonadosomatic index, condition factor, length-weight relationship and the growth parameter (b) of 185 specimens were studied during the period of low precipitation (June-September). Fish samples were obtained along a 100 m stretch of each stream, and some habitat variables recorded. ANOVA and Kruskal-Wallis tests indicated a similarity in most of the analyzed traits, with exception of the mean length of immatures, Gonadosomatic Index of mature males and condition factor of immatures and mature adults. Also, slope tests of the length-weight relationship were significantly different for immatures. The observed differences were attributed to heterogeneity in food availability and/or other site-specific factors, which may influence growth and/or breeding aspects among the studied localities. The approach used herein may improve understanding of trait plasticity under natural conditions, helping to understand fish-community responses to anthropogenic changes.(AU)

Negative effect of ectoparasite burdens on the condition factor from farmed tilapia Oreochromis niloticus in the Yucatan, Mexico.

Nile tilapia (Oreochromis niloticus Linnaeus, 1758) is one of the most important aquaculture species in the world, and, when introduced, the ectoparasites of Nile tilapia have followed. Currently, farmers worldwide consider these ectoparasites harmless, but intensities can reach up to 1000 individuals per fish in tropical regions. In this cross-sectional study, we used the condition factor to estimate the potential effects of low (45 ± 31 ectoparasites per fish) and high (295 ± 191) ectoparasitic burdens across 28 tilapia farms and included the analysis of the effects of 44 management and environmental variable from the farms. A stepwise procedure in a multiple linear regression analysis retained the variables that explained the most variance, which was the ectoparasitic burden (57 %). We found significantly higher values of the condition factor in Nile tilapia with low ectoparasitic burden than in those with high ectoparasitic burden. Additionally, Nile tilapia with a high ectoparasitic burden weighed less than half than those with a low burden (102 ± 105 g versus 230 ± 128 g, respectively). We also found a significant non-linear, negative relationship between the ectoparasitic burden and the relative condition factor values per fish, which was most likely due to an increase in gill mucus caused by the ectoparasitic burden that depleted energy in the Nile tilapia. The economic consequence of the ectoparasitic burden translated roughly into a loss up to 12-15 % in profit margin per ton of fish, based on the price of Nile tilapia in the Mexican market.

First record of parasitism by Probopyrus pandalicola (Isopoda, Bopyridae) on the freshwater prawn Macrobrachium acanthurus (Decapoda, Palaemonidae) and ecological interactions.

In this study, we aimed to record, for the first time, parasitic infestation by the isopod Probopyrus pandalicola on the prawn Macrobrachium acanthurus, as well as to register some ecological interactions. We hypothesized that the parasitic infection is able to negatively affect the prawn's nutritional condition and that this interaction can modify growth relationships in male individuals. We collected both parasitized (n = 25) and parasite-free (n = 25) individuals in several locations of the Contas River, state of Bahia, Brazil, which had their morphometric characteristics determined, including of the parasites. Relative growth models were constructed for both groups in order to compare slopes and intercepts and determine if the growth patterns are modified by the parasite. We also determined the body condition of the prawns, which was also compared between the two groups. Our results clearly demonstrated that the parasitic infection is able to induce modifications in relative growth patterns in male individuals and that this isopod is capable of reducing the nutritional condition of the prawns. This study indicates that this parasite can induce deleterious effects in the prawn, but individually. Further studies should be conducted to assess the relevance of our findings in conservation and management.

Occurrence of Neoechinorhynchus curemai (Acanthocephala: Neoechinorhynchidae) in Prochilodus nigricans (Characiformes: Prochilodontidae), in southwestern Amazon

Prochilodus nigricansis extensively exploited in fishing and aquaculture activities in the Brazilian Amazon, it is the definitive host for Neoechinorhynchus curemaiNoronha, 1973. Thus, the present study aimed to evaluate the occurrence of N. curemaiin P. nigricansand the parasite-host relationship in three rivers (Juruá, Crôa and Môa) in the municipality of Cruzeiro do Sul, state of Acre, Brazil. Fish were caught, weighed, measured, and subjected to necropsy, and the gastrointestinal tract and viscera were analyzed. A totalof 178 specimens of N. curemaiwere found in 61 infected fish, with the (p= 58.62%). The prevalence, mean intensity, and mean abundance were higher in hosts from the Môa River, and lower from the Juruá River. Regarding the length-weight relationship, the b-value did not differ statistically from three (b=3) for fish species in the three locations, nor in parasitized and non-parasitized species. In addition, growth was considered isometric, and in the case of the relative condition factor, there was no difference in fish hosts between the three rivers. The correlation between parasite intensity, condition factor, length, and weight of P. nigricanswas not significant. Thus, this parasite infestation varied between the habitats. However, this did not influence the growth and development of the hosts.(AU)

Occurrence of Neoechinorhynchus curemai (Acanthocephala: Neoechinorhynchidae) in Prochilodus nigricans (Characiformes: Prochilodontidae), in southwestern Amazon

Prochilodus nigricansis extensively exploited in fishing and aquaculture activities in the Brazilian Amazon, it is the definitive host for Neoechinorhynchus curemaiNoronha, 1973. Thus, the present study aimed to evaluate the occurrence of N. curemaiin P. nigricansand the parasite-host relationship in three rivers (Juruá, Crôa and Môa) in the municipality of Cruzeiro do Sul, state of Acre, Brazil. Fish were caught, weighed, measured, and subjected to necropsy, and the gastrointestinal tract and viscera were analyzed. A totalof 178 specimens of N. curemaiwere found in 61 infected fish, with the (p= 58.62%). The prevalence, mean intensity, and mean abundance were higher in hosts from the Môa River, and lower from the Juruá River. Regarding the length-weight relationship, the b-value did not differ statistically from three (b=3) for fish species in the three locations, nor in parasitized and non-parasitized species. In addition, growth was considered isometric, and in the case of the relative condition factor, there was no difference in fish hosts between the three rivers. The correlation between parasite intensity, condition factor, length, and weight of P. nigricanswas not significant. Thus, this parasite infestation varied between the habitats. However, this did not influence the growth and development of the hosts.

Probiotic expressing heterologous phytase improves the immune system and attenuates inflammatory response in zebrafish fed with a diet rich in soybean meal.

Although aquaculture is among the fastest growing food production sectors in the world, one of the bottlenecks for the continuity of its expansion is the dependence of animal protein on commercial feed formulations. Vegetable proteins are an alternative due to the low cost and high availability. However, this protein source is accompanied by a series of antinutritional and pro-inflammatory compounds, including phytate. Phytases can be added in feed for phytate degradation and increase nutrient availability. However, the use of purified phytases significantly increases the production costs. An interesting alternative is to use probiotics genetically modified as bioreactors for phytase production. In the present study, a strain of Bacillus subtilis secreting a fungal phytase was used to evaluate the effect of a feed with high content of soybean meal on zebrafish (Danio rerio). We analysed the condition factor (K) of fish, and the expression of genes related to the immune system, inflammatory response and oxidative. stress. The results obtained demonstrate that the transgenic probiotic was efficient in improving the fish condition factor, stimulating the immune system, reducing the inflammatory response and oxidative stress. Thus, probiotics acting as phytase bioreactors can be considered an interesting tool for the adaptation of commercial species to feed of lower cost.

Ingestion of plastic fragments by the Guri sea catfish Genidens genidens (Cuvier, 1829) in a subtropical coastal estuarine system.

One of the most recognized anthropogenic impacts in marine environments is solid waste pollution, especially plastic, which can be ingested by fish, thus interfering with their health. In this context, the aim of this study is to describe the ingestion of plastic fragments and to identify the possible effect of this contamination in the condition factor of Genidens genidens in the Laguna Estuarine System. The stomach contents of 92 G. genidens (26 juveniles and 66 adults) were analyzed. The Index of Relative Importance was performed to identify the contribution of each prey item. Condition factor (CF) was used to analyze the effect of plastic ingestion on the fish's body condition (by comparing individuals in the same ontogenetic phase). For the juveniles, eight items were observed, the most important of which were Penaeidae, followed by Portunidae and plastic. For the adults, 12 items were observed, the most important of which were Penaeidae, Portunidae, Polychaeta, and plastic. The analysis of CF demonstrated higher values for individuals without plastic in the stomach, which indicated a better health condition. The CF of a fish may be affected by variations in the physiological condition, environmental stresses, and nutritional and biological variations, and could be used to compare the body condition or health of a fish species. The ingestion of plastic could significantly influence the worst body condition of the individuals that were analyzed in the present study. The plastic pollution in marine coastal waters is associated with the appropriate waste management levels.

Reproductive indicators of the endemic species Astyanax bifasciatus (Teleostei: Characidae) in a tributary of the Lower Iguaçu River Basin, Brazil

The reproductive process promotes morphophysiological and behavioral changes in fish species throughout their life cycle. Its success is vital to define their resilience in the environment. This study aimed to evaluate the reproductive biology of the endemic fish species Astyanax bifasciatusin a tributary of the Lower Iguaçu River Basin, Paraná, Brazil. Fish were collected monthly at four sites along the Jirau Alto River in the city of Dois Vizinhos from October 2015 to September 2016. A standardized catch effort with gill nets and fish traps was used. In the laboratory, standard length and total weight were recorded. After anesthesia, the animals were sectioned to macroscopically determine the sex, sexual maturity stage, and presence of celomatic fat. The gonads and liver were removed to determine the gonadosomatic and hepatosomatic indexes, respectively. A total of 160 individuals (104 femalesand 56 males) were used. The gonadosomatic index, frequency of the gonadal maturation stages, and condition factor showed a long reproductive period with two investment cycles for both sex. Length at first sexual maturity was 4.57 cm for females and 3.56 cm for males. The reproductive data corroborate the generalist profile of the species and demonstrate a high degree of adaptive capacity, even in smaller tributaries.

Morphometric relationships and seasonal variation in size, weight, and a condition index of post-settlement stages of the Caribbean spiny lobster.

Spiny lobsters have a protracted pelagic, oceanic larval phase. The final larval stage metamorphoses into a non-feeding postlarva (puerulus) that actively swims towards the coast to settle in shallow habitats and does not resume feeding until after the molt into the first-stage juvenile. Therefore, the body dimensions and nutritional condition of both settled pueruli and first juveniles are likely to vary over time, potentially playing a crucial role in the recruitment to the benthic population. We compared carapace length (CL), height (CH), and width (CW); total length (TL), and body weight (W) between pueruli and first juveniles of the Caribbean spiny lobster, Panulirus argus, as well as morphometric relationships between both developmental stages. Except for CL, all other dimensions were larger in first juveniles, but more markedly CH and W. The slopes of the CH vs CL, CW vs CL, and W vs CL regressions differed significantly between stages, and all log-transformed relationships showed isometry in both stages, except for the CH vs CL relationship, which showed positive allometry. These results reflect a morphological change from the flatter, more streamlined body of the puerulus, to the heavier, more cylindrical body of the juvenile. We also analyzed seasonal variations in CL, W, the W/CL index (a morphometric condition index), and a modified W/CL index (i.e. after controlling for a significant effect of CL) of both stages using individuals monthly collected over 12 consecutive seasons (Autumn 2010-Summer 2013). In both stages, all three variables exhibited significant seasonal variation. For pueruli, the modified W/CL index differed from average in only two seasons, winter 2011 (higher) and summer 2013 (lower), but showed great within-season variation (larger coefficients of variation, CV), potentially reflecting variability in nutritional condition of larvae prior to metamorphosis and in the distances swum by individual pueruli to the settlement habitats. For first juveniles, the modified W/CL index was higher than average in winter and spring 2011, and lower in autumn 2011 and winter 2012, but showed less within season variation (smaller CVs), suggesting a combination of carry-over effects of puerulus condition and effects of local conditions (e.g., food availability and predation risk). These findings warrant further investigation into factors potentially decoupling settlement from recruitment processes.

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post-natal life.

The present study analysed the condition factor (K) and the hepato-somatic index (I H ) of the Brazilian sharpnose shark Rhizoprionodon lalandii during its entire life cycle. Discontinuity of liver growth was observed after sexual maturity. High condition values were recorded in the length classes of 300-350 mm (neonates), when the livers represented about 8% of total mass, decreasing until the length classes of 400-450 and 450-500 mm in females and males, respectively. Seasonal analysis exhibited low I H values in the summer, while for K, low values were in spring, indicating greater investment for body growth during spring and for gonad maturation in summer. Such findings indicate that this small coastal shark species accumulates reserve substances in the liver that will be used during reproduction. The decline in I H values in juveniles suggests that reserves provisioned by the mother to the neonate liver can be used in the first months of life.

Feeding ecology and ingestion of plastic fragments by Priacanthus arenatus: What's the fisheries contribution to the problem?

Atlantic Bigeye (Priacanthus arenatus) is a demersal species from the Priacanthidae family with little literature relating to its biology and catch aspects. Due to this lack of research, the focus of this effort was to describe the feeding preferences of Atlantic Bigeye and to evaluate the influence of plastic debris derived from the local fisheries activities on its diet. The most important items were Corophiidae, Penaeidae, Actinopterygii, Isopoda, Cephalopoda, Policheta and plastic. Plastic was present in 49.17% of the stomachs analyzed. A total of 210 plastic fragments were found, and 63% were derived from fishing. Of those, 55% were derived from paint fragments from vessels and 8% from synthetic fibers (PA). The results suggest that plastic fragments found in stomachs are related to the species' natural diet and that this debris is locally deposited in the coastal environment. Fishing resources appear to have been affected by this local marine pollution.