Catfish Species Research Articles

Length-weight relationship and condition factor revealed possibility of mix strains in Clarias gariepinus population of Oueme Valley, Benin Republic (West Africa)

Growth behaviour (Length-Weight Relationship-LWR), condition factor (K) and phylogenetic linkage of sourced Clarias gariepinus from Oueme valley (main catfish brooder source in Benin) was investigated to understand possible sources of diversity in growth pattern in spawned C. gariepinus . 30 random C. gariepinus ‘labelled’ brooders from sellers in each of Adjohoun(wild-habitat); Dangbo(culture-habitat) and Porto-Novo(culture-habitat) were characterized for differences(p<0.05) in Mean Length-ML (cm), Mean Weight-MW (kg), condition factor (K) and growth behavior (LWR intercept-a; slope-b) in sexes and unsexed populations. 16S barcode gene sequences of 10 random tissue subsamples from each group (n=30) were analyzed for genetic linkages using Maximum Likelihood Method. ML was similar across populations; MW and K similar across Dangbo and Porto-novo; MW similar across sexes of populations; ML and K similar across sexes in Adjohoun, but differ across sexes in Dangbo and Porto-Novo. In unsexed populations, Iintercept-a ranged 0.46(Porto-novo)-0.82(Dangbo), Slope-b -1.37(Porto-novo), 2.14(Dangbo), 2.60(Adjohoun); intercepts were 0.94; 0.63, 0.87; 0.78, and 0.36; 0.61 in respective male and female Adjohoun, Dangbo and Porto-novo; Slope ‘b’ 2.97; 2.05(Adjohoun); 2.87; 2.34(Dangbo), -1.23;-1.78(Porto-novo). Irrespective of sexes, growth was negative allometry in Adjohoun and Dangbo; positive allometry in Porto-novo. 80%Porto-novo were closest to Clarias batrachus ; 20% closest to C. gariepinus x C. batrachus- crossbred; 70%Dangbo closest to C. gariepinus x C. batrachus- crossbred , 10% closest to Clarias batrachus . 20% closest to C. gariepinus. 90%Adjohoun was closest to C. gariepinus x C. batrachus -crossbred, 10% closest to C. gariepinus . Growth behaviour and condition factor diverged irrespective of sexes in populations. Each populations contained mixed strains of Catfish species mistaken as C. gariepinus whose growth pattern could be influenced by growth behaviour of the dominant strain . Dominance of C. batrachus x C. gariepinus- crossbreds’ in culture-Dangbo and Wild-Adjohoun signals possible introgression of the invasive C. batrachus gene, indicating dire need for stricter management and conservation of local catfish gene pool for posterity.

Finding the suitable catfish species for cage aquaculture in a freshwater swamp

The experiment was carried out for 94 days in the renowned Ratargul Freshwater Swamp Forest of Bangladesh in order to assess the production performance and economics among three locally high-demand catfish species with a view to selecting suitable species for cage culture. Magur (

Species determination and heavy metal content of sailfin catfish (Pterygoplichthys pardalis) from Tempe Lake, South Sulawesi, Indonesia

Abstract. Kasmiati, Latuconsina N, Putri AA, Khasanah R, Nurfaidah, Fahrul, Syahrul, Metusalach. 2022. Species determination and heavy metal content of sailfin catfish (Pterygoplichthys pardalis) from Tempe Lake, South Sulawesi, Indonesia. Biodiversitas 23: 4409-4417. Sailfin catfish is invasive alien species that has become dominant in Indonesian freshwater, including in Tempe Lake, South Sulawesi, Indonesia. Despite their abundance, these sailfin catfish are not utilized because of suspicions that they are contaminated by heavy metals that can endanger human health. The purposes of this study were to determine the sailfin catfish species present in Tempe Lake and measure the content of heavy metals Hg, Pb, and Cd in various body parts. Fish species were identified based on abdominal patterns, while heavy metal content was meaured by atomic absorption. The heaviest two body parts were the head (34.04%) and flesh (26.64%), heavy metal content detected in the liver (0.0402-0.0928 mg/kg), gut (0.0322-0.0671 mg/kg), gills (0.319-0.0865 mg/kg), dark meat (0.0268-0.0589 mg/kg), white meat (0.0221-0.0470 mg/kg), bones (0.0180-0.0519 mg/kg), and skin/scales (0.0257-0.0675 mg/kg). All of them were below the FAO/WHO 1989, US-EPA 1999, and the Indonesian National Standards. The government health and safety guidelines for fish to be safe for human consumption were Hg &lt;0.005 mg/kg, Pb&lt;0.10 mg/kg and Cd&lt;0.02 mg/kg. Therefore the abundant sailfin catfish Pterygoplichthys pardalis in Tempe Lake could be consumed directly and as ingredients in other food products.

Identification and antimicrobial sensitivity profiling of bacteria isolated from cultured catfish shing (Heteropneustes fossilis)

The cultivated species of catfish (Heteropneustes fossilis), also known as "Shing" has a delectable flavor, a high market value, a high nutritional and therapeutic value, and a high iron and calcium content. In Bangladesh, the shing (H. fossilis) fish is one of the most sought-after, popular, and extremely valuable indigenous species. The purpose of this research was to isolate bacterial pathogens from infected shing (H. fossilis) fish and determine their antibiotic sensitivity. In total, 76 medically infected shing fish were collected by the cultivators from their own ponds in the Jashore district, in southern Bangladesh. Disease-causing bacteria were found in 62 (81.5%) of the infected fish, while normal flora were found in 14 (18.5%) of the 76 samples. There were 62 pathogenic bacterial isolates found, and Aeromona spp., Pseudomonas spp., Streptococcus spp., Flavobacterium spp. and Vibrio spp. were the main causes of disease in the sick fish. Among the species of bacteria that were isolated, the prevalence of the largest pathogens, Aeromonas spp. was 34 (51.4%) and the prevalence of the second largest, Pseudomonas spp. was 13 (20.3%). The other isolates were comprised of the following species: Streptococcus spp. 9 (9.4%), Flavobacterium spp. 4 (5.4%) and Vibrio spp. 2 (4.1%). The farming of shing (H. fossilis) fish has been increased rapidly all around the country. Therefore, bacterial infections may reduce the production of fish in ponds. In this research, bacterial strains showed a high degree of sensitivity to ciprofloxacin (77%) and levofloxacin (54%). Significantly, oxytetracycline (52%) enrofloxacin (45%) and erythromycin (45%) were the intermediate/moderate sensitive antibiotics. All the strains were found to be resistant to amoxicillin 57/62 (92%) and neomycin 42/62 (68%). The findings of this research will be beneficial to fish farmers in the treatment of bacterial infections in fish, as these diseases are caused by microorganisms. The PCR method might be studied further as a means of identifying all bacterial cultures, which would require additional research.

Lapillusotolith shape, a useful taxonomic feature for the identification of sea catfishes (Ariidae: Siluriformes) from the north‐eastern Pacific

Otolith shape is widely used as a taxonomic feature in fish systematics. In Siluriformes, the lapillus otolith is the most relevant character for taxonomic purposes, although its discriminant potential has not been assessed quantitatively. Our study model were sea catfishes of the family Ariidae from the north-eastern Pacific as representatives of Siluriformes, a taxon with increased taxonomic complexity. The lapillus otolith shape obtained by geometric morphometrics showed high discrimination potential both at the genus and species levels with an overall classification accuracy of c. 93% (K=0.92). Due to the strong species delimitation exhibited by lapillus otolith shape, the descriptions and identification keys provided here are the most useful materials to recognize the eight sea catfish species evaluated. The shared similarities in lapillus otolith shape among species seem to be more influenced by phylogenetic relationships than other factors such as habitat. The lapillus otolith shape is the most powerful taxonomic feature discovered so far for the identification of sea catfishes from the north-eastern Pacific.

A New Species of Air-Breathing Catfish (Clariidae: Clarias) from Salonga National Park, Democratic Republic of the Congo

A new species of air-breathing catfish, Clarias monsembulai, is described from Congo River tributaries within and bordering the Salonga National Park (Democratic Republic of the Congo). The new taxon is recognized by its exceptionally long, white barbels, which lend a superficial resemblance to Clarias buthupogon, from which it differs in characters of the cleithrum and pigmentation patterning. We suggest placement of this species into the subgenus Clarioides but note the current dearth of morphological data to unite members of this group. We additionally discuss the validity of the subspecies Clarias angolensis macronema.

Biology of selected Clarias catfish species used in aquaculture

Catfish are important organisms used extensively in aquaculture. For this review, we are focusing on specific species of catfish in the genus Clarias, primarily Clarias batrachus, C. gariepinus and C. macrocephalus, because of their widespread use in aquaculture and the considerable amount of information that has been amassed on different aspects of their biology. This review summarizes information available on topics ranging from the taxonomy and geographic distribution of these catfish to work done on them at the genetic, molecular biological and genomic levels. This information may be useful in future efforts to grow and expand their use in aquaculture.

Nanopore metatranscriptomics reveals cryptic catfish species as potential Shigella flexneri vectors in Kenya

Bacteria in the Shigella genus remain a major cause of dysentery in sub-Saharan Africa, and annually cause an estimated 600,000 deaths worldwide. Being spread by contaminated food and water, this study highlights how wild caught food, in the form of freshwater catfish, can act as vectors for Shigella flexneri in Southern Kenya. A metatranscriptomic approach was used to identify the presence of Shigella flexneri in the catfish which had been caught for consumption from the Galana river. The use of nanopore sequencing was shown to be a simple and effective method to highlight the presence of Shigella flexneri and could represent a potential new tool in the detection and prevention of this deadly pathogen. Rather than the presence/absence results of more traditional testing methods, the use of metatranscriptomics highlighted how primarily one SOS response gene was being transcribed, suggesting the bacteria may be dormant in the catfish. Additionally, COI sequencing of the vector catfish revealed they likely represent a cryptic species. Morphological assignment suggested the fish were widehead catfish Clarotes laticeps, which range across Africa, but the COI sequences from the Kenyan fish are distinctly different from C. laticeps sequenced in West Africa.

Evaluation of the dietary supplementation of autochthonous bacteria on growth, survival and resistance to Aeromonas veronii challenge in Clarias batrachus and Heteropneustes fossilis

AbstractThe study focused on identifying autochthonous bacteria from the indigenous catfish intestine and evaluating their impacts on survival, growth and against Aeromonas veronii infection in Clarias batrachus and Heteropneustes fossilis under laboratory conditions. Candidate bacteria were isolated using Nutrient Agar (NA) and de Man, Rogosa and Sharpe (MRS) agar in duplicate. An immersion technique was employed to determine the biosafety of these isolates in both catfish species at a dose of 107 CFU/mL. Three experimental diets: D1 (basal diet + putative Bacillus sp., 108–109 CFU/g), D2 (basal diet + 3% BioFav Aqua) and D3 (basal diet + putative Lactobacillus sp., 108–109 CFU/g) were prepared to conduct a 4‐week long feeding trial, whereas the control diet received no probiotic supplementation. The probiotic performance was analysed by comparing the growth performance and survival of C. batrachus and H. fossilis. Resistance against Aeromonas veronii infection was determined by a challenge test of catfish. Initially, 16 autochthonous isolates were collected, and among them, an isolate from C. batrachus intestine and another from the gut of H. fossilis were selected for further studies. A series of biochemical analyses identified that the putative bacteria were Bacillus sp. and Lactobacillus sp., respectively. The biosafety test showed no clinical signs of infection or mortality among experimental catfishes. All probiotic‐treated fish showed higher growth increments than control. Incorporation of Bacillus sp. and Lactobacillus sp. in the basal diet significantly (p &lt; 0.05) improved growth and survival in both catfish, where Bacillus sp. showed the best effects in C. batrachus, and Lactobacillus sp. in H. fossilis. Intramuscular (IM) injection with A. veronii revealed that probiotic‐treated fish had better survival rates. The study demonstrated the potentiality of autochthonous bacteria to enhance growth, survival, feed efficiency and immunity and hence recommended as a better health management approach in catfish aquaculture.

Expression of the Growth Hormone Gene during Early Development of Tiger Shovelnose Catfish (Pseudoplatystoma Fasciatum Linnaeus, 1766)

The early development stage of fish is crucial in fish farming, especially catfish species with cannibal characteristics, such as the Tiger Shovelnose Catfish (Pseudoplatystoma fasciatum Linnaeus 1766). Growth plays an essential role in fish’s life, which is influenced by the mechanism of growth hormone (GH). This study analyzed the level of growth hormone (GH) gene expression at several early developmental stages of Tiger Shovelnose Catfish. Samples were taken from an embryo, three days post hatched (dph) larvae to 60 dph juvenile. Isolation of mRNA was carried from the pituitary gland located at the head of the fish. Gene expression analysis was performed using RT-PCR method that compared GH/b-actin genes from band thickness. The results of the analysis showed the highest expression at 60 dph juvenile. The most significant increase in GH gene expression occurred from the egg to three dph larvae (P &lt; 0.05), then decreased to 20 dph juvenile. The increased phenotypic growth was seen from the increased length and weight at 45 dph juveniles. This indicates the amount of growth hormone released at the juvenile stage of 20 dph, thus triggering rapid growth in the next stage at 45 dph juvenile. Growth hormones can act as growth biomarkers in Tiger Shovelnose Catfish. The novelty of this study was to determine the level of GH gene expression in Pseudoplatystoma fasciatum ornamental fish as the object of research. Suggestions for further research to explore genes related to growth mechanisms through transcriptomic and proteomic technologies.

Longitudinal habitat gradient affects diet and body condition of riverine fish: A case study of Pelteobagrus catfishes in the Three Gorges Reservoir, China

AbstractTo understand how riverine fish respond to longitudinally different habitats created by impoundment, we selected three congeneric yellow catfish species (Pelteobagrus spp.) as a model system to assess changes in diet, prey selectivity, and body condition among the lotic, transitional, and lentic habitats along the Three Gorges Reservoir. Our results add to previous findings highlighting a shift in fish diets from diverse zoobenthos to shrimp‐dominated as the river becomes lentic by showing spatial segregation in the size of shrimp prey consumed. Relative to the available shrimp populations, catfish populations selected smaller shrimp in the upper (lotic) section and larger shrimp in the middle (transitional) and lower (lentic) sections. Complementary body condition indices exhibited a consistent spatial pattern, where populations in the lotic zone were healthier than those in the transitional and lentic zones. This pattern seems to result from a greater nutrient value of zoobenthos, the dominant food in the lotic zone, relative to shrimps. Our results suggest that these generalist fish species have adapted to the spatial habitat gradient and maintained their populations, but the impoundment has deeply influenced their energy acquisition and allocation.

RETRACTED: SEQUENCE ANALYSIS OF MITOCHONDRIAL CYTOCHROME C OXIDASE I GENE IN CATFISHES: AN INSIGHT INTO BARCODING AND PHYLOGENY

The standard methodology of DNA barcoding consists of clustering a taxonomic group using the Neighbour-joining (NJ) clustering method, which utilizes the divergence gap between species as a yardstick of species differentiation. With this approach, the present study is framed to decipher the divergence trend in catfish species - Clarias batrachus, C. gariepinus, Heteropneustes fossilis, Sperata seenghala, Wallago attu and Rita rita. The partial segment of the mitochondrial cytochrome c oxidase I subunit gene was used as the molecular marker of investigation. The intraspecific and interspecific divergence values were compared where a considerable gap was found between them. The average intraspecific divergence was found to be &lt; 1%, while the average interspecific divergence found in the range of 16-24% which encompasses the divergence even at the family level. The NJ clustering has differentiated these species and has also shown phylogenetic insights as well. The species relatedness which appeared in NJ clustering was then reconfirmed using the Maximum likelihood (ML) approach with bootstrap support to trace their phylogenetic relationship. Interestingly, both NJ and ML clustering were found parallel, which assured the presence of phylogenetic signals in NJ tree too. Our study has successfully shown the role of intraspecific and interspecific divergence in species differentiation in catfishes, and simultaneously highlights the appearance of phylogenetic relationships in the NJ tree. A more comprehensive way of sampling is also discussed that could assist in looking deep into the divergence role to differentiate higher taxonomic levels.&#x0D; &#x0D; Retraction Notice: This paper has been retracted from the journal after receipt of written complains regarding authorship dispute. This journal is determined to promote integrity in research publication. This retraction is in spirit of the same. After formal procedures editor(s) and publisher have retracted this paper on 19th December-2022.

Hubungan Panjang Berat dan Kondisi Habitat pada Dua Spesies Catfish di Sungai Barumun Kabupaten Labuhanbatu

Catfish is a demersal fish inhabiting the waters of the River. There are two species that are often caught in the Barumun River: the blacktip sea catfish (Piicofillis dussumieri Valenciennes, 1840) and the grey eel catfish (Plotosus canius Bleeker, 1858). Both of these species have economic value that is quite important for the coastal communities of Labuhanbatu Regency. Fishing gear used to take samples of fish in the form of: trap, gill nets, and fishing rods. All fish caught were then measured in total length using a ruler and their weight using analytical scales. Analysis of research data using the Linear Allometric Model (LAM) equation. Based on the results of the study the length relationship of blacktip sea catfish weight obtained values b = 32,38 and R2 = 0.95 and grey eel catfish obtained values b = 2,56 and R2 = 0.26. It was concluded that the long relationship ofblacktip sea catfish weight is allometric positive and grey eel catfish is allometric negative. The results of observations of water quality parameters for temperature (29-30ºC), brightness (0.5 – 0.8 m), current speed (0.8 – 0.9 m/s), salinity (5.1 - 15.3 ‰), pH (6), and dissolved oxygen (6.9 – 7.2 mg/L) and habitat conditions of both catfish species are still in accordance with quality standards for river waters.

Biochemical composition of some catfishes from a coastal river of Bangladesh in relation to a biometric indicator

The proximate contents (protein, lipid, ash, and moisture) of three catfish species (Pangasius pangasius, Clupisoma garua, and Silonia silondia) were investigated from a coastal river of Bangladesh. The proximate composition was determined using the AOAC (1990) standard procedure. The average length and weight of the fish samples used in the experiment were 21.50 ± 1.61 cm and 65.55 ± 13.12 g; 19.67 ± 0.21 cm and 50.74 ± 3.13 g; 18.2 ± 1.21 cm and 43.40 ± 10.42 g for P. pangasius, C. garua, and S. silondia, respectively. The P. pangasius, C. garua, and S. silondia were rich protein sources, with 20.19%, 18.86%, and 15.24%, respectively. On the other hand, the lipid and ash contents were ranged between 2.11% to 3.07% and 0.52% to 2.28% respectively. The present study disclused water as the most abundant element in fish bodies ranging from 75.05% (P. pangasius) to 79.60% (S. silondia). In log-transformed data, the weight of the fish body had a very significant positive relationship with most of the studied body constituents. In all three fish species, total length in log-transformed data and Fulton's condition factor showed a highly significant positive relationship with most of the studied body constituents. These findings suggest that biological differences like length and weight across species can influence the fishes biochemical composition that should be established.

Comparative transcriptomes and metabolomes reveal different tolerance mechanisms to cold stress in two different catfish species

Cold stress is detrimental to physiological fitness and can lower the survival rate, especially for the fishes with low ability of cold-tolerance. To further understand the coping mechanism on cold stress, we applied an integrated metabolomic and transcriptomic analyses to reveal the hepatic metabolic responses when cold-sensitive red-tail catfish and cold-tolerant longsnout catfish were exposed to lower temperature by a programmed cooling method. Differentially expressed genes (DEGs) and significantly different metabolites (DMs) related to lipid synthesis and metabolism were identified from comparative metabolomic and transcriptomic data, respectively. The results indicate that the two catfish species show significantly different responses to the cold stress. Synthesis and metabolism of related lipids can be mobilized quickly and efficiently to compensate for the integrity and maintain the fluidity of cell membranes in the early cooling stage in longsnout catfish, but not in red-tail catfish. The anti-oxidative and apoptosis system can be activated positively in the middle and late cooling stages in longsnout catfish, but it is inhibited in red-tail catfish, which may be the potential reason for red-tail catfish death. Therefore, this study provides key information for understanding low-temperature tolerance mechanisms in catfish.

The Analysis of Genetic Variation in the Mitochondrial ND6 Gene and its Application for the Identification of Indonesian Catfish Species

Background: Catfish is a freshwater and saltwater fish type with a wide distribution throughout the Indonesian archipelago. This study was conducted to analyze Indonesian catfish’s genetic diversity and evolutionary relationships based on the mitochondrial ND6 gene. Methods: Twenty-eight catfish samples were collected from nine rivers and one ocean in seven provinces of Indonesia. The MT-ND6 gene was amplified by using a set of primers (BaungND6F and BaungND6R). The MEGA X software was used to examine the MT-ND6 sequences for genetic variation and phylogenetic relation between Indonesian catfish populations. Result: There were 167 nucleotide site variations and thirty-two amino acid variations in the MT-ND6 gene. The genetic difference among populations ranges from 0.9 to 25% and the average evolutionary divergence in the overall populations was 14%, with catfish BB and PM having the closest genetic distance, while the farthest is BF to MP and BF to MS. In conclusion, the phylogenetic tree indicated that there were four distinct catfish clades in this study: MP, MS, KR, PM, BB and KS had been grouped with Hemibagrus nemurus (Bagridae family), EM had been grouped with Mystus vittatus (Bagridae family), BSBJ had been grouped with Pangasius pangasius (Pangasiidae family) and PD and BF had been grouped with Netuma thalassina (Ariidae family).

Silurichthys exortivus, a new catfish (Teleostei: Siluridae) from eastern Borneo, Indonesia.

Silurichthys exortivus, a new species of silurid catfish, is described from the Mahakam River drainage in eastern Borneo. The new species can be distinguished from congeners in lacking a dorsal fin, having 4 (vs. 67) principal rays on the upper caudal-fin lobe and a combination of: body depth at anus 14.0% SL, caudal peduncle depth 5.1% SL, pelvic fins absent, 54 anal-fin rays, caudal fin with asymmetrical lobes (upper lobe 1.1 times longer than lower), 48 vertebrae, 1 gill raker on the first branchial arch, and a mottled brown body. Based on the reduced number of principal caudal-fin rays, S. exortivus, S. ligneolus and S. sanguineus are hypothesized to form an exclusively Bornean clade.

The first record of 4 species of monogenean flatworm on catfish (Clarias fuscus, Hemibagrus spilopterus and Pangasius macronema) in the Dak Lak, Vietnam

Catfish (Order Siluriformes) is one of the largest orders of teleosts containing about 4,100 species with with highly diverse and distributed worldwide, representing about 12% of all teleosts and ∼6.3% of all vertebrates. Catfish are of economic and ecological importance; many large fish species are raised or caught for food, and small fish are cultured as ornamental. Like other fish species, monogenean is a common ectoparasites on catfish with more than 379 species recorded. The current study collected 77 individuals of three catfish species, including Hong Kong catfish Clarias fuscus (n = 21), black spotted catfish Hemibagrus spilopterus (n = 17) and long barbels pangasiid catfish Pangasius macronema (n = 39)) in Dak Lak in 2016 - 2017. Based on morphological and genetic (18S rRNA gene) characters, this study recorded four new dactogyrid monogenean species on the hosts and in Vietnam, in which, Thaparocleidus armillatus and Mizelleus siamensis on P. macronema; Bychowskyella tchangi on C. fuscus, and Cornudiscoides longicirrus on H. spilopterus. Phylogenetic tree constructed of four 18S rRNA sequences from the current study and six sequences on Genbank showed Bychowskyella spp. species formed monophyletic clusters and is sisterly related to the remaining of the species. C. longicirrus species was clustered in the separate clade, while M. siamensis species exhibited paraphyly when grouped with species of the genus Thaparocleidus. There is a need for further analysis of taxonomic characteristics and molecular markers diversity (e.g. Cytochrome oxidase subunit (COI mtDNA), 16S rRNA) to determine the taxonomic position of monogenean species.

Estimating the total length of Mekong giant catfish, Pangasianodon gigas, in an aquarium via stereo-video shooting and direct linear transformation.

The Mekong giant catfish (MGC), Pangasianodon gigas, is one of the world's largest catfish species. Endemic to the Mekong River system, the MGC is critically endangered. Six MGC were transported from Thailand to the Gifu World Freshwater Aquarium (GWFA) in Japan in May 2004. The MGC have not been measured since they were introduced to the GWFA due to the challenges associated with their large size. Traditional methods, such as anesthesia and net-capture, could harm the fish, potentially reducing the population further. However, understanding the ecology of the species is essential to conservation efforts. Seasonal feeding rhythms and long-term fasting were previously observed in captive MGCs. To investigate the effect of long-term fasting on MGC growth, total length measurements are necessary. In this study, we applied a noncontact method to estimate the total length via image analysis. We shot a stereo-video of free-swimming MGC in the aquarium tank using two digital video cameras and analyzed the 3D images using the direct linear transformation method. We successfully estimated the total length of each MGC individual without contacting the fish. This accurate estimation method is versatile, simple, and useful in aquarium breeding and is also recommended from the viewpoint of animal welfare because it is a noninvasive method of measurement.

Sounds and associated morphology of Hypostomus species from South‐East Brazil

AbstractHypostomus is the most diverse genus within Loricariidae. These catfish species exhibit a very conservative morphology with relatively few external characteristics that differ between different species. In consequence, there is a challenge to understand the distinction of species of this genus. This study aims to describe the sounds produced by ten species of Hypostomus from Araguari River and Paraopeba River (Minas Gerais, Brazil), to examine whether acoustic features could be used to distinguish between the species, and to understand the corresponding sound production mechanisms. The fish were recorded making sounds by holding them in hand underwater, in a glass tank on the river shore next to where they had been caught. All ten species produced sounds, and no effect of body size on acoustic features was observed. Furthermore, the species could not be distinguished using acoustic features. Likewise, all the studied species exhibited similar bony ridges on the dorsal processes of the pectoral spine. Since the sounds produced by the fish do not seem to exhibit interspecific specificity, they do not appear to have a role in behaviours requiring conspecific recognition, such as reproduction. Sound production may have an alarm, distress, or acoustic aposematism function warning predators of the presence of pectoral spines, which have an anti‐predatory function in this clade.