Bathygobius Soporator Research Articles

Length-Weight Relationship and Condition Factor of Porogobius schlegelii and Bathygobius soporator from Buguma Creek, Rivers State, Nigeria

The present study investigated the length-weight relationship and condition factor of two fish species Bathygobius soporator and Porogobius schlegelii, in Buguma Creek. Over a three-month period (March – May 2018), 2000 different size fish samples each of B. soporator (1000) and P. schlegelii (1000) were collected by artisanal fishermen in Buguma Creek. The study collected total length and total weight data using a meter ruler and a digitally sensitive scale (Sartorius Model H987) for each species allowing determination of the growth exponent(b), coefficient of determination (r2) and mean condition factor values for the fish species. The study found that B. soporator ranged in total length from 7.00 to 18.80cm and from 2.00 to 14.70g, while P. shlegelli measured 4.50 to 11.50cm and weighed 1.30 to 7.10g. The growth exponent (b) ranged from 1.77 to 2.64 for B. soporator and 1.26 to 2.41 for P. schlegelli, indicating a negative allometric growth pattern for the two species, while the r2 values for B. soporator ranged between 0.61 and 0.89 and for P. schlegelli between 0.52 and 0.81 in Buguma Creek. The mean condition factor values for B. soporator ranged from 0.88 to 1.51, while for P. schlegelli it ranged from 0.38 to 0.39, suggesting that B. soporator had a higher condition factor than P. schlegelli, indicating better health and body condition for B. soporator and raising concern for the health of the P. schlegelli population in Buguma Creek. There is therefore an urgent need to establish conservation areas or fishing restrictions to allow the P. schlegelli fish population to recover and maintain a healthy population of the creek.

Laboratory-reared larvae and juveniles of three species of the genus Bathygobius (Gobiidae)

Larvae and juveniles of three species in the family Gobiidae are described based on laboratory-reared material: Bathygobius fuscus to post-settlement, Bathygobius cyclopterus to 2 days old, and Bathygobius petrophilus to just after hatching. Newly hatched larvae of these species are distinguishable from each other by the melanophore arrangements on the dorsal region of the trunk, ventrally near the tip of the tail, and along the lateral midline. The early development of Bathygobius fuscus was similar to that described previously for Bathygobius soporator but differed in the appearance of melanophores and the shape of the second dorsal fin and anal fin.

Shelter cleaning of frillfin goby as non-reproductive behaviour

Various animals perform nest cleaning behaviour for breeding and keeping the hygiene of their living environment. Some fishes are also known to clean the nest for breeding and parental care, but it is unclear whether they clean it under non-breeding conditions. This study investigated the shelter cleaning behaviour of frillfin goby (Bathygobius fuscus) during the non-breeding season. All individuals of both males and females removed unknown objects (fishing sinkers) from their shelter, whereas they did not move many sinkers in the feeding area located outside the shelter. Subsequent video observation showed that fish removed sinkers using their tail fin, snout, mouth, and pectoral fins. The results suggest that frillfin goby clean their shelter even under non-breeding conditions. Furthermore, this study found that they can use pectoral fins to move objects, just like other animals use their hands and forelimbs to do so, supporting the developmental relationship between digits and pectoral fins in terms of functionality.

Analysis of a hypersaline drought-prone estuary reveals low density and diversity of fish eggs and larvae

We analyzed fish eggs and larvae in an estuary under severe drought conditions. We detected an inverse salinity gradient, with values increasing from the mouth to the upper estuary. Egg densities decreased from the estuarine mouth to the upstream areas following the salinity increase for all three mesh net sizes. This pattern was also found for the density of larvae, which decreased in estuarine regions with hypersalinity (38 to 62). The low diversity constituted only nine fish species, which were classified as anadromous (Anchoa hepsetus), estuarine and marine (Bathygobius soporator, Hippocampus reidi, Eucinostomus sp., and Diapterus auratus), marine estuarine-opportunist (Caranx latus and Bardiella rochus), and marine stragglers (Echeneis naucrates and Haemulon sp.). In addition, we observed an oversimplification of the assemblage to include stress-tolerant estuarine and marine species. Our baseline results suggest that this hypersaline estuarine ecosystem has lower densities and diversity than a healthy mangrove system.

Heavy metals concentrations in water, sediment, water hyacinth (Eichhornia crassipes) and Frillfin Goby (Bathygobius soporator, Cuvier and Valenciennes, 1837) from Ologe Lagoon, Southwest, Nigeria

The level of heavy metals in water, sediment, water hyacinth (Eichhornia crassipes) and frillfin goby (Bathygobius soporator) from Ologe Lagoon and its tributaries were monitored because of the importance of the water bodies to the socio-economic well-being of the rural population. Physico-chemical parameters and selected heavy metals (Fe, Zn, Cu, Pb and Cd) contents of water, sediment, E. crassipes and B. soporator from six sampling stations in Ologe Lagoon were measured monthly from February to November, 2015. The range of concentration of heavy metals in sediment are: Fe (454±112-2756±1213mg/kg), Zn (3.89±3.08-18.7±6.83mg/kg), Cu (7.68±5.65-36.8±16.9mg/kg), Pb (6.24±2.56-11.2±4.45mg/kg) and Cd (0.42±0.17-0.92±0.42mg/kg). Heavy metal concentration in E. crassipes were 68.5±16.5-987±86.8mg/kg, 13.2±6.40-162±46.2mg/kg, 0.56±0.25-6.54±1.45mg/kg, 5.06±2.41-12.2±4.71mg/kg and 0.28±0.22-1.21±0.49mg/kg for Fe, Zn, Cu, Pb and Cd respectively. The concentrations of heavy metals in the muscle of B. soporator in wet season were: Fe, 8.30±2.29 mg/kg; Zn, 0.78±0.28 mg/kg; Cu, 16.20±6.20 mg/kg; Pb, 2.21±0.33mg/kg; Cd, 0.16±0.05mg/kg while in dry season, they were: Fe, 27.19±7.28 mg/kg; Zn, 24.47±6.27 mg/kg; Cu, 0.18±0.16 mg/kg; Pb, 1.72±0.07mg/kg; Cd, 0.19±0.03mg/kg. Hardness and turbidity showed significant (p<0.05) spatial variation. Concentrations of Fe, Zn and Cu in sediment varied significantly (p<0.05) among the sampling sites but Pb and Cd did not. The heavy metal content of water hyacinth from the six sampling stations exhibited significant (p<0.05) spatial variation except Cd. The concentrations of Fe, Zn and Cu in B. soporator were significantly (p<0.05) affected by season but Pb and Cd were not. Although only Pb exceeded the FAO/WHO maximum permissible limits in the tissue of B. soporator, regular monitoring of Ologe Lagoon is advocated in order stern further deterioration of the ecosystem and to protect the rural population that depend on it for sustenance.

The fish community in Gulf of Mexico mangroves, a response to hydrological restoration

The present study evaluated the ecological response of fish fauna to hydrological restoration in a mangrove area in Terminos Lagoon in the Gulf of Mexico. In two years, environmental parameters and ichthyofauna were obtained in a channel under restoration and a conserved channel. The fish fauna was composed of 12 species. As a result of the restoration process, changes in composition and abundance of some species were detected. The presence of visiting marine species Bathygobius soporator and Eucinostomus melanopterus, and an increase in the abundance of resident fish, livebearers species, were recorded. Richness, diversity, and evenness vary significantly between channels. Generalized linear mixed models indicated that the abundances of resident and overall fishes were significantly related to water depth, temperature, and salinity. The results suggest that fish are an ecological indicator of the mangrove reconnection with the Terminos Lagoon and the restoration of natural tidal flow in the short term. Long-term systematic monitoring of fish fauna will promote a better understanding of the restoration of mangroves and corresponding changes in the function of this ecosystem.

Assessment of Some Heavy Metals in Two Species of Goby (Porogobius Schelegelii and Bathygobius Soporator) From Buguma Creek, Niger Delta

This study investigated the heavy metal concentrations in different organs such as gills, muscles, liver and gatro-intestinal tract (GIT) of two species of Goby: Porogobius schelegelii and Bathygobius soporator from Buguma Creek, Rivers State, Nigeria. The fish samples were collected from the creek and were preserved in ice chest box and transported to the laboratory for analysis. Samples were digested by using standard laboratory methods. The concentrations of metals were analyzed using a Varian AA240 Fast Sequential Flame Atomic Absorption Spectrophotometer (AAS). The Results obtained indicated that heavy metals such as Chromium (Cr), Lead (Pb), Zinc (Zn), Cadmium (Cd), and Nickel (Ni) were significantly higher (p<0.05) in the liver of the two species than in the muscle, gills and the GIT. Comparatively, the concentrations of these metals were higher in the specie B.soporator than P. schelegelii in all the organs of the fishes under consideration. The heavy metal concentrations recorded in this study were above the limits recommended by Food and Agricultural Organization/ World Health Organization. The high concentration of heavy metals above permissible level suggests the need for caution during the consumption of these species from Buguma Creek due to health implications associated with heavy metals.

Biological and ecological aspects of Bathygobius soporator (Valenciennes, 1837) (Perciformes, Gobiidae) from Santa Catarina, Southern Brazil

Bathygobius soporator (popularly known as "Maria da toca") is a species that, although abundant, is little studied in aspects regarding growth, feeding and reproduction in southern Brazil. Studies on trophic ecology still raise questions on the species’ actual diet, especially in the context of algae participating as a food resource or an accidental intake. Thus, this study aims to fill this gap, evaluating the growth, feeding, and reproduction of this species. Monthly samples from two periods (1997-1998 and 2005-2006) were analyzed for growth, feeding, and reproduction parameters, totalizing 1177 individuals evaluated. Our results demonstrate that Bathygobius soporator is a species of fast development, reaching the age of first maturation before the first year of life. It presents a sexual dimorphism, being males larger than females. Reproductive peaks occur in the spring and summer months. The species presented a broad trophic spectrum, including algae as the main food resource, not just an accidental intake. The omnivorous-opportunistic trophic ecology of this species is emphasized, agreeing with the information of previous studies.

Intertidal Biogeographic Subprovinces: Local and Regional Factors Shaping Fish Assemblages

Intertidal zones shelter a wealth of species and natural resources, provide important ecological services, and sustain several economic activities in coastal communities. However, the tidepool fish species that inhabit the intertidal zone are subject to a wide array of impacts due to the human presence and their accessibility, creating a challenge for the mitigation of habitat loss, in particular in tropical regions where the ecology and distribution of species are poorly known. In this study, we investigated tidepool fish species distribution patterns systematically across ca. 4,900 km of tropical Brazilian coastline (00–21° latitude) in order to verify the latitudinal trends and environmental variables influencing tidepool communities. A total of 5,113 fish specimens belonging to 67 taxa were collected at the 19 sites, revealing four distinct biogeographic subprovinces: Amazon Estuary (AE), Northern Mangrove (NM), Northeastern Semiarid (NS), and Tropical Warm (TW). Distance-based linear modeling evidenced in sequence water salinity, tidal range, shape of rocky shore formation, algae cover, distance to subtidal zone, latitude and rainfall as the most important environmental variables to shape biogeographic subprovinces. Fish species such as Bathygobius soporator, Bathygobius geminatus, Labrisomus nuchipinnis, and Scartella cristata presented wide distribution, occupying more than one subprovince. The trophic structure of the tidepool fishes also varied among subprovinces, with carnivores being associated with the AE subprovince, omnivores with the NM, and herbivores dominating the NS and TW. These findings reinforce the determining role of local and regional factors in the geographic distribution of fish and, in particular, highlight a new arrangement for the intertidal subprovinces of the tropical Brazilian shoreline, which may provide a valuable tool for the more effective management and conservation of this vulnerable ecosystem at the land-ocean interface.

Trophic relationships in tidepool fish assemblages of the tropical Southwestern Atlantic

AbstractTrophic studies are fundamental to understanding the dynamics of assemblages and functional roles of species within ecosystems, contributing to the identification of factors responsible for the organization and structure of communities. This study aimed to analyse the trophic organization of tidepool fish assemblages in the tropical Southwestern Atlantic, based on the underlying idea that food resources are not limiting and that trophic guild formation is not driven by food competition. Diets were based on feeding index values of food categories for 12 representative species collected in six tidepools (20º49′ S, 40º36′ W) at quarterly intervals (2005 to 2007). The main food categories were small crustaceans, polychaetes and macroalgae. Multivariate techniques evidenced two multispecific trophic guilds: small‐prey carnivores, including Bathygobius soporator, Bathygobius geminatus, Malacoctenus delalandii and Halichoeres poeyi, and herbivores, including Sparisoma axillare and Acanthurus bahianus. Other species presented significantly different diets and were classified into the following guilds: omnivores feeding on filamentous algae and copepods (Abudefduf saxatilis); large‐prey carnivores (Labrisomus nuchipinnis); omnivores feeding on polychaetes and filamentous algae (Stegastes fuscus); and polychaete feeders (Ahlia egmontis). Gymnothorax funebris and Gymnothorax moringa were classified as carcinophagores and piscivores, respectively. Trophic organization appears related to species convergence toward the use of abundant food resources, driven by a combination of factors allowing some resource partitioning through inter‐specific differences in consumer size, microhabitat, behavior, and trophic specialization.

Ventilation responses to predator odors and conspecific chemical alarm cues in the frillfin goby

The chemical detection of predation risk is direct when based on predator odors, or indirect when an injured conspecific or heterospecific signal it. Physiological adjustments may be necessary in parallel to defensive reactions to cope with an imminent risk. Here, we tested the effects of predator odors and conspecific chemical alarm cues in ventilation response (VR) of frillfin goby, Bathygobius soporator, because this response increases oxygen uptake for supporting behavioral tasks. No VR change was detected in response to odors of predators (catfish) that fed on conspecific, heterospecific fish (tilapia), or were deprived of food and to non-predator (tilapia) that fed chow (non-specific odor control) and odor eluent. The goby's VR, however, increased in response to conspecific alarm cues, but not to heterospecific cues or eluent. Clearly, the VR response in fish depends on the nature of the chemical cue. It is in line with ‘threat-sensitive hypothesis’ as a chemical cue from an injured prey might mean a foraging predator, whilst the mere presence of a predator odor might not. In addition, because VR can increase, decrease or remains unchanged in response to predation risk in other fish species (including other gobies), we reinforces the species-specific chracteristic of VR responses in fish, regarding the results obtained here for frillfin gobies.

Latitudinal Influence on the Sexual Dimorphism of the Marine Fish Bathygobius soporator (Gobiidae: Teleostei)

Environmental gradients in a marine setting may have significant effects on morphological variations and evolutionary patterns, including sexual dimorphism variations within and between fish populations. We analyzed sexual shape and size dimorphism in accordance with Rensch and Bergmann’s rules in five coastal populations of the gobiid Bathygobius soporator along 4000 km of the Brazilian coastline. The populations differ significantly in sexual body shape dimorphism, with a tendency toward reduced intrapopulation dimorphism, increasing with latitude. Body size variation was significant between populations and population vs. sex, and inverse to Bergmann’s rule. Moreover, size dimorphism among populations of B. soporator does not follow Rensch’s rule. These data represent a rare example of inter and intrapopulation spatial variation in sexual dimorphism associated with latitude in marine fish. This suggests a complex and particularized scenario of biotic and abiotic interactions acting on local populations of B. soporator in extensive coastal areas of the Western Atlantic, with profound implications for species evolution.

Structure and composition of fish assemblages from São Sebastião Channel tide pools, southwestern Atlantic

Abstract Organisms living in tide pools in the intertidal zone are exposed to daily and abrupt changes in temperature, dissolved oxygen, pH and salinity, during tidal cycles. Fish assemblages in tide pools are usually very different from those in surrounding areas; resident species exhibit morphological and ecological adaptations to deal with such a variable environment. In this study, we described the environmental conditions and the fish diversity and composition from four tide pools at the continental margin of the São Sebastião Channel, São Sebastião (23º41'-23º54'S; 45º19'-45º30'W), in southeastern Brazil. Monthly, from January to December 2011, we sampled four tide pools (12 samples per pool), applying a standard protocol to record environmental variables, and visual censuses to record abundance, richness and composition of fish assemblages. Environmental and fish data were compared among tide pools and periods throughout the year (warm and cold) using both univariate and multivariate analyses of variance. Tide pools showed significant environmental differences, mainly in area, volume and complexity of substrata. We observed 13 species of fishes (10 families), which belong to five trophic guilds (roving herbivores, territorial herbivores, mobile invertebrate feeders, omnivores and carnivores). Density and richness of fish were almost constant during the studied period, except for a reduction in fish density in São Francisco's Beach during a cold period. However, assemblages from the sampled tide pools differed from each other in composition and relative abundance of species, resulting in four distinct assemblage structures. Bathygobius soporator was the dominant species in most of the tide pools, corresponding to 66% of all recorded fish. The tide pool from Baleeiro's Point was intermediate in size, but was covered by a complex algae community and supported the most diverse fish assemblage, suggesting that habitat complexity may contribute to the diversity of fish.

Sex differences on the feeding of the gobiid fish Bathygobius soporator in tide pools of Maiandeua Island, Pará, Brazil

Abstract Bathygobius soporator (Valenciennes, 1837) is one of the most common fishes in tide pools in the estuary of Pará state, and has an omnivorous feeding habit. This study examined the diet of the species in Maiandeua Island, and aimed to: (i) describe the diet of B. soporator through indexes based on the occurrence and weight of consumed items; and (ii) evaluate if there is variation in diet composition between males and females. Frequency of Occurrence, frequency of weight and Alimentary Index were calculated for each item, and differences in the diet composition of males and females were observed through multivariate analyses (ANOSIM, NMDS and SIMPER). Bathygobius soporator presented carnivorous feeding habit, eating mainly crustaceans, and differences among males and females were observed, males consuming smaller amounts of crustaceans and including algae in their diet.

Dietary overlap and food resource partitioning among fish species of a tropical estuary in Northeastern Brazil

The current work investigates dietary overlap and food partitioning among nine abundant carnivorous fishes caught in the shallow waters of the Paraíba do Norte river estuary, Paraíba State, Brazil. Fishes were sampled with a beach seine net between January and December 2008 and a total of 958 specimens had their stomach content analyzed. Crustacea was the dominant food resource for Lutjanus alexandrei, L. jocu and Bathygobius soporator, whereas Telostei were consumed mainly by Centropomus undecimalis and C. parallelus. In contrast, Polychaeta were preyed upon mainly by Diapterus rhombeus, Eucinostomus argenteus, Sciades herzbergii and S. parkeri. Although most species consumed similar food items, they did that in varying proportions and amounts. Overall, the niche overlap among species was low (< 0.60), but there were several cases where pair of species had their feeding niche highly overlapped (between 0.72 and 0.97). These findings corroborate the hypothesis that food resource partitioning determines species coexistence in estuarine tropical environments.

Checklist of tidepool fishes from Jericoacoara National Park, southwestern Atlantic, with additional ecological information

Ichthyofauna from 29 tidepools in Jericoacoara National Park (Ceará State, Brazil) was sampled. A total of 733 fishes, comprising 16 species belonging to 12 families, was collected. The three most abundant species were the frillfin goby Bathygobius soporator, the sergeant-majorAbudefduf saxatilis and the molly miller Scartella cristata. An invasive species from the Indo-Pacific, the Muzzled blenny Omobranchus punctatus, was also recorded. The known geographic distribution of the blenny Hypleurochilus fissicornis was extended approximately 2,500 km northward. These findings highlight the lack of knowledge of the rocky intertidal ecosystems along the Brazilian coast, an area that needs more sampling effort and ecological data.

Effect of warming rate on the critical thermal maxima of crabs, shrimp and fish

The threat of global warming has prompted numerous recent studies on the thermal tolerance of marine species. A widely used method to determine the upper thermal limit has been the Critical Thermal Maximum (CTMax), a dynamic method, meaning that temperature is increased gradually until a critical point is reached. This method presents several advantages over static methods, however, there is one main issue that hinders interpretation and comparison of CTMax results: the rate at which the temperature is increased. This rate varies widely among published protocols. The aim of the present work was to determine the effect of warming rate on CTMax values, using different animal groups. The influence of the thermal niche occupied by each species (intertidal vs subtidal) and habitat (intertidal vs subtidal) was also investigated. CTMax were estimated at three different rates: 1°Cmin−1, 1°C30min−1 and 1°Ch−1, in two species of crab, Eurypanopeus abbreviatus and Menippe nodifrons, shrimp Palaemon northropi and Hippolyte obliquimanus and fish Bathygobius soporator and Parablennius marmoreus. While there were significant differences in the effect of warming rates for some species, for other species warming rate produced no significant differences (H. obliquimanus and B. soporator). While in some species slower warming rates lead to lower CTMax values (P. northropi and P. marmoreus) in other species the opposite occurred (E. abbreviatus and M. nodifrons). Biological group has a significant effect with crabs' CTMax increasing at slower warming rates, which did not happen for shrimp and fish. Subtidal species presented lower CTMax, at all warming rates tested. This study highlights the importance of estimating CTMax values at realistic rates that species encounter in their environment and thus have an ecological value.

Micronucleus test in frillfin goby Bathygobius soporator (Valenciennes, 1873) from tide pools of Salvador city (Brazil).

The genotoxic effects of metals were evaluated in Bathygobius soporator using the micronucleus test. The frequencies of micronuclei in fish erythrocytes cells of sampling points were elevated when compared to the controls (P < 0.05). Micronucleus test in fish erythrocytes were useful to determine genotoxic effects of metals substances in the fish, reducing the pain and suffer of the animal testing. The first PC (70.56%) of principal component analysis (PCA) account for almost all of the variance, and Pearson’s correlation coefficient between the first PC and micronucleus frequency of sampling points (P1-P10) was performed (r = -0.704, P = 0.023).

Cortisol influences the antipredator behavior induced by chemical alarm cues in the Frillfin goby

We evaluated the effect of increased plasma cortisol levels on fish antipredator behavior induced by conspecific chemical alarm cues. The experimental model for the study was the Frillfin goby Bathygobius soporator. We first confirmed that the alarm substance induces typical defensive antipredator responses in Frillfin gobies and described their alarm substance cells (epidermal ‘club’ cells). Second, we confirmed that intraperitoneal cortisol implants increase plasma cortisol levels in this species. We then demonstrated that exogenous cortisol administration and subsequent exposure to an alarm substance decreased swimming activity to a greater extent than the activity prompted by either stimulus alone. In addition, cortisol did not abolish the sheltering response to the alarm chemical cue even though it decreased activity. As predators use prey movements to guide their first contact with the prey, a factor that decreases swimming activity clearly increases the probability of survival. Consequently, this observation indicates that cortisol helps improve the antipredator response in fish.

Length-weight relationships for 25 fish species from three coastal lagoons in Southeastern Brazil

Summary This work analyzes the relationship between length and weight for 25 fish species belonging to 15 families in three mixohaline/hypersaline coastal lagoons in Southeastern Brazil. The study presents the first estimation of L–WRs for six species (Anchoa tricolor, Brevoortia aurea, Jenynsia multidentata, Ctenogobius boleosoma, Microgobius meeki and Bathygobius soporator) and maximum lengths for four species (Atherinella brasiliensis, Jenynsia multidentata, Poecilia vivipara and Microgobius meeki) that are greater than previously recorded.