Aulonocara Research Articles

Effect of the Addition of Shrimp Head Flour in Feed on Increasing the Color Brightness of Peacock Cichlid Fish (Aulonocara sp.).

Effect of the Addition of Shrimp Head Flour in Feed on Increasing the Color Brightness of Peacock Cichlid Fish (Aulonocara sp.).

Beef liver and Goat Blood Waste Supplemented Diet Induced Growth Changes in Fresh Water Ornamental Fish Peacock Cichlid (Aulonocara hansbaenschi)

The growth of ornamental fishes is an important quality criterion in the aquarium fish industry. To compile and summarize recent investigations into different growth sources used in ornamental fish feed formulations and to highlight the research gaps and investigation needs in the field of aquaculture. An attempt has been made to evaluate the effects of growth by Beef liver and Goat blood waste. The fish feed at 10%, 20%, 30%, 40%, 50% and 60% diet on the growth in peacock cichlid (Aulonocara hansbaenschi). For the isonitrous (39% of protein) diets, beef liver and goat blood waste are prepared individually and offered to the candidate fish at 5% of body weight at ad libitum for a period of 40 days. The result indicates that in the skin and muscle tissue of candidate protein, carbohydrate and lipid contents were found to vary between diets and also during various intervals over experimental periods. The works of various researchers, on various fish species have led to the development of recommended inclusion levels of Beef liver and goat blood meal in the diet of the following aquaculture species. The result indicated the incorporation of 30% diet Beef liver and Goat blood waste in diet was found better to enhance the growth in peacock cichlid’s (Aulonocara hansbaenschi). Diet is considered as optimum dietary level to enhance feed intake growth.

Diverse Levels of Amaranthus dubiusleaves on Growth and Carotenoid Improvements in Fresh Water Ornamental Fish Peacock Cichlid (Aulonocara hansbaenschi)

Attractive coloration and growth of ornamental fishes are important quality criteria in the aquarium fish industry. Colour-producing carotenoids cannot be synthesized by ornamental fish, so they must rely on dietary carotenoids in natural or synthetic forms to achieve their color pigmentations. The aim of this review is to compileand summarize recent investigations into different carotenoid sources used in ornamental fish feed formulations and to highlight the research gaps and investigation needs in the field of aquaculture. An attempt has been made to evaluate the effects of diets containing 0%, 2.5%, 5%, 7.5%, 10% Amaranthus dub the growth and carotenoid changes in peacock cichlid (Aulnocara hansbaenschi).This isonitrous (40% protein) diet supplemented with Amaranthus dubius leaves diet was prepared and offered ad libitum to the experimental fish in 5% body weight for 45 days. The results indicated that in the skin and muscle tissue of experimental fish, the growth and carotenoid contents were found to vary between control diets and also during the time intervals of experimental period. The results indicated that incorporation of 10% diet A. dubiusleaves in the diet was found to enhance the growth and coloration of peacock cichlid’s (Aulnocara hansbaenschi). This is considered the optimum dietary level to enhance feed intake growth and coloration.

First Record of the Water Mold Achlya bisexualis (Saprolegniaceae) Isolated from Ornamental Fish in South Africa.

The order Saprolegniales (Class Oomycota) is a group of fungus-like eukaryotic microorganisms that have been associated with infections in fish and fish eggs. Infections with microorganisms from this order are clearly evident because they have a cotton wool-like appearance. The aim of this study was to characterize and identify an oomycete that was isolated from the eye of an Orange Blotched Peacock Cichlid Aulonacara sp. A sample of cotton wool-like mycelia was isolated and single-spore isolations were conducted. Molecular characterization and phylogenetic analysis of the ITS1-5.8-ITS2 rDNA region for all isolates were used for species identification. Following molecular identification, one isolate was used to culture and characterize the reproductive structures. Physiological characterization entailed incubating the isolate on potato dextrose agar (PDA) at five different temperatures, ranging from 5°C to 25°C, to monitor growth rates. A multiple sequence alignment showed 100% similarity between all of the single-spore isolates and alignment with other Achlya bisexualis strains. Long, coarse hyphae with zoosporangia and gemmae typical of the order Saprolegniales were observed with an optimal growth rate at 25°C. The oomycete that was isolated from an Orange Blotched Peacock Cichlid was identified as A.bisexualis, the first record of this species in South Africa.

A COMPARISON OF ALFAXALONE AND TRICAINE METHANESULPHONATE (MS-222) IN TWO FISH SPECIES

The purpose of this study was to evaluate the effectiveness of the alfaxalone formulation Alfaxan™ as an immersion anesthetic in tropical fish species compared to that of tricaine methanesulfonate (MS-222). 22 black spot barbs (Puntius filamentosis) measuring (mean±SD) 11.4 ±1.4 cm in body length and 22 peacock cichlids (Aulonocara spp.) (measuring 8.4 ± 1.6cm were anesthetized in water baths containing 100 mg/L of MS-222 buffered with 200 mg/L of bicarbonate or 5 mg/L of alfaxalone following a 2-week washout period. Time to maximum effect, recovery periods, self-righting, spontaneous swimming movements, opercular movements, and response to noxious stimuli were recorded. The following results are for the black spot barbs following MS-222 and alfaxalone anesthesia, respectively: mean times (±SD) to surgical anesthesia were 5.5 ± 2.11 and 3.27 ± 1.72 minutes and mean recovery times were 2.95 ± 0.9 and 9.14 ± 3.15 minutes. The peacock cichlid anesthetic protocols for MS-222 (20 of 22 cichlids) and alfaxalone (20 of 21 cichlids) produced the following results, respectively: mean times (±SD) to surgical anesthesia were 14.75 ±5.43 and 11.1 ± 9.84 minutes and mean recovery times were 3.6 ±0.82 and 22.4 ±11.3 minutes. Median recovery time from 5 mg/L alfaxalone was significantly longer (P < 0.001) in both species, by 5 minutes for black spot barbs and by 17 minutes for peacock cichlids. Variation in induction and recovery times between species was observed, with black spot barbs having significantly (P < 0.0001) faster induction times when treated with both drugs, and a faster recovery time from 5 mg/L alfaxalone.

Detection of artificial water flows by the lateral line system of a benthic feeding cichlid fish.

The mechanosensory lateral line system of fishes detects water motions within a few body lengths of the source. Several types of artificial stimuli have been used to probe lateral line function in the laboratory, but few studies have investigated the role of flow sensing in benthic feeding teleosts. In this study, we used artificial flows emerging from a sandy substrate to assess the contribution of flow sensing to prey detection in the peacock cichlid, Aulonocara stuartgranti, which feeds on benthic invertebrates in Lake Malawi. Using a positive reinforcement protocol, we trained fish to respond to flows lacking the visual and chemical cues generated by tethered prey in prior studies with A. stuartgranti Fish successfully responded to artificial flows at all five rates presented (characterized using digital particle image velocimetry), and showed a range of flow-sensing behaviors, including an unconditioned bite response. Immediately after lateral line inactivation, fish rarely responded to flows and the loss of vital fluorescent staining of hair cells (with 4-di-2-ASP) verified lateral line inactivation. Within 2 days post-treatment, some aspects of flow-sensing behavior returned and after 7 days, flow-sensing behavior and hair cell fluorescence both returned to pre-treatment levels, which is consistent with the reported timing of hair cell regeneration in other vertebrates. The presentation of ecologically relevant water flows to assess flow-sensing behaviors and the use of a positive reinforcement protocol are methods that present new opportunities to study the role of flow sensing in the feeding ecology of benthic feeding fishes.

First record of the invasive blue peacock cichlid Cichla piquiti Kullander and Ferreira 2006 (Cichliformes: Cichlidae) in the Paraíba do Sul river basin, south eastern Brazil

First record of the invasive blue peacock cichlid Cichla piquiti Kullander and Ferreira 2006 (Cichliformes: Cichlidae) in the Paraíba do Sul river basin, south eastern Brazil

Complete mitochondrial genome of Aulonocara stuartgranti (Flavescent peacock cichlid)

In this study, the complete mitochondrial genome of the flavescent peacock cichlid Aulonocara stuartgranti was determined. The mitochondrial genome is 16 669 bp in length, and encodes 1 D-loop region, 2 ribosomal RNA genes, 13 protein-coding genes, and 22 transfer RNA genes. Average GC content of this genome is 45.8%. ATP8 and ATP6 genes overlap by nine nucleotides, ND5 and ND6 genes by four nucleotides, and ND4L and ND4 genes share six nucleotides. All coding genes use ATG as start codon with except COX1 initiating with GTG. The phylogenetic tree involving 22 available closely related species further validated the newly determined sequences and phylogeny of A. stuartgranti.

Feeding in the dark: lateral-line-mediated prey detection in the peacock cichlid Aulonocara stuartgranti

The cranial lateral line canal system of teleost fishes is morphologically diverse and is characterized by four patterns. One of these, widened lateral line canals, has evolved convergently in a wide range of teleosts, including the Lake Malawi peacock cichlids (Aulonocara), and has been attributed to its role in prey detection. The ability to study Aulonocara in the laboratory provides an opportunity to test the hypothesis that their reported ability to feed on invertebrate prey living in sandy substrates in their natural habitat is the result of lateral-line-mediated prey detection. The goal of this study was to determine whether Aulonocara stuartgranti could detect hydrodynamic stimuli generated by tethered brine shrimp (visualized using digital particle image velocimetry) under light and dark conditions, with and without treatment with cobalt chloride, which is known to temporarily inactivate the lateral line system. Fish were presented with six pairs of tethered live and dead adult brine shrimp and feeding behavior was recorded with HD digital video. Results demonstrate that A. stuartgranti: (1) uses the same swimming/feeding strategy as they do in the field; (2) detects and consumes invertebrate prey in the dark using its lateral line system; (3) alters prey detection behavior when feeding on the same prey under light and dark conditions, suggesting the involvement of multiple sensory modalities; and (4) after treatment with cobalt chloride, exhibits a reduction in their ability to detect hydrodynamic stimuli produced by prey, especially in the dark, thus demonstrating the role of the lateral line system in prey detection.

The Casiquiare river acts as a corridor between the Amazonas and Orinoco river basins: biogeographic analysis of the genus Cichla

The Casiquiare River is a unique biogeographic corridor between the Orinoco and Amazonas basins. We investigated the importance of this connection for Neotropical fishes using peacock cichlids (Cichla spp.) as a model system. We tested whether the Casiquiare provides a conduit for gene flow between contemporary populations, and investigated the origin of biogeographic distributions that span the Casiquiare. Using sequences from the mitochondrial control region of three focal species (C. temensis, C. monoculus, and C. orinocensis) whose distributions include the Amazonas, Orinoco, and Casiquiare, we constructed maximum likelihood phylograms of haplotypes and analyzed the populations under an isolation-with-migration coalescent model. Our analyses suggest that populations of all three species have experienced some degree of gene flow via the Casiquiare. We also generated a mitochondrial genealogy of all Cichla species using >2000 bp and performed a dispersal-vicariance analysis (DIVA) to reconstruct the historical biogeography of the genus. This analysis, when combined with the intraspecific results, supports two instances of dispersal from the Amazonas to the Orinoco. Thus, our results support the idea that the Casiquiare connection is important across temporal scales, facilitating both gene flow and the dispersal and range expansion of species.

Evaluation of the Ecological Compatibility of Butterfly Peacock Cichlids and Largemouth Bass in Puerto Rico Reservoirs

AbstractIntroduction of peacock cichlids Cichla spp. into tropical and subtropical systems where they can successfully overwinter and reproduce has been a common practice in fisheries management. We evaluated the compatibility of nonnative butterfly peacock cichlids Cichla ocellaris and largemouth bass Micropterus salmoides in Puerto Rico reservoirs using (1) controlled juvenile interaction experiments, (2) examination of hatching periodicity and diet overlap of juveniles in a reservoir environment, and (3) comparison of adult catch data from 10 Puerto Rico reservoirs. In the juvenile interaction experiments, butterfly peacock cichlid juveniles in ponds with largemouth bass had slower growth in length (P = 0.020) and weight (P = 0.003) and lower survival (P = 0.002) than in ponds with only butterfly peacock cichlids. In reservoirs, largemouth bass spawning typically occurred 2–3 months before butterfly peacock cichlid spawning, which resulted in substantial size differences between the juveniles of the two species. Butterfly peacock cichlids fed almost exclusively on threadfin shad Dorosoma petenense; the largemouth bass diet included threadfin shad but was much more diverse. Correlation coefficients were negative for comparisons of adult largemouth bass and butterfly peacock cichlid catch rates in the reservoirs sampled. Pooled catch data from all reservoirs showed a significant inverse relationship in relative abundance (P = 0.026). Catch rates from reservoirs with and without butterfly peacock cichlid populations indicated that largemouth bass densities were higher in single‐predator systems (mean = 85.1/h) than in dual‐predator systems (9.8/h).

Mercury Contamination in Freshwater, Estuarine, and Marine Fishes in Relation to Small-Scale Gold Mining in Suriname, South America

The extent of mercury contamination in Surinamese food fishes due to small-scale gold mining was investigated by determination of the total mercury concentration in 318 freshwater fishes, 109 estuarine fishes, and 110 fishes from the Atlantic Ocean. High background levels were found in the piranha Serrasalmus rhombeus (0.35 microg Hg x g(-1) muscle tissue, wet mass basis) and the peacock cichlid Cichla ocellaris (0.39 microg x g(-1)) from the Central Suriname Nature Reserve. Average mercury levels in freshwater fishes were higher in piscivorous species than in nonpiscivorous species, both in potentially contaminated water bodies (0.71 and 0.19 microg x g(-1), respectively) and in the control site (0.25 and 0.04 microg x g(-1), respectively). Mercury concentrations in piscivorous freshwater fishes were significantly higher in rivers potentially affected by gold mining than in the control site. In 57% of 269 piscivorous freshwater fishes from potentially contaminated sites, mercury levels exceeded the maximum permissible concentration of 0.5 microg Hg x g(-1). The highest mercury concentrations (3.13 and 4.26 microg x g(-1)) were found in two piranhas S. rhombeus from the hydroelectric reservoir Lake Brokopondo. The high mercury levels in fishes from Lake Brokopondo were to some extent related to gold mining because fishes collected at eastern sites (i.e., close to the gold fields) showed significantly higher mercury concentrations than fishes from western localities. In the estuaries, mercury levels in ariid catfish (0.22 microg x g(-1)) and croakers (0.04-0.33 microg x g(-1)) were distinctly lower than those in piscivorous fishes from contaminated freshwater sites. In the isolated Bigi Pan Lagoon, the piscivores snook Centropomus undecimalis (0.04 microg x g(-1)) and tarpon Megalops atlanticus (0.03 microg x g(-1)) showed low mercury levels. Mercury levels were significantly higher in marine fishes than in estuarine fishes, even with the Bigi Pan fishes excluded. High mercury concentrations were found in the shark Mustelus higmani (0.71 microg x g(-1)), the crevalle jack Caranx hippos (1.17 microg x g(-1)), and the barracuda Sphyraena guachancho (0.39 microg x g(-1)), but also in nonpiscivorous species such as Calamus bajonado (0.54 microg x g(-1)), Haemulon plumieri (0.47 microg x g(-1)), and Isopisthus parvipinnis (0.48 microg x g(-1)). Mercury levels were positively correlated with the length of the fish in populations of the freshwater piscivores S. rhombeus, Hoplias malabaricus, and Plagioscion squamosissimus, in estuarine species (Arius couma, Cynoscion virescens, and Macrodon ancylodon), and in S. guachancho from the Atlantic Ocean.

Age structure and growth of peacock cichlids from rivers and reservoirs of Venezuela

Age structure and growth of peacock cichlids from rivers and reservoirs of Venezuela

Age structure and growth of peacock cichlids from rivers and reservoirs of Venezuela

Cichla temensis collected in Venezuela attained a mean standard length of 440 mm, and C. orinocensis and C. intermedia mean lengths of 309 and 321 mm, respectively. There was little evidence of size differences between sexes. Opaque zones on otoliths corresponded to the period of peak of reproductive activity and low fish body condition (K). When aggregated across sites, linear estimates for growth of fish &gt;age I were 57·5, 27·6, and 19·6 mm year1 for C. temensis, C. orinocensis, and C. intermedia, respectively. Fish from the Cinaruco River appeared to spawn at age I, and prior to first maturation had grown 25, 21, and 23 mm month1, respectively, for C. temensis, C. orinocensis, and C. intermedia. There was little intersite variation in growth rates, and differences in sizes of conspecifics from different sizes were due to age differences. Cichla in captivity spawn several times per year. The present results indicate that the annual cycle or tropical wet/dry seasonality promotes reproductive seasonality in Cichla. The energetic cost of reproduction and brood defence probably constrains most individuals to one spawn per year. Conversely, populations living in relatively aseasonal reservoir environments may have several spawns per year, in which case growth zones on hard structures are difficult to interpret.

Ecology of Cichla (Cichlidae) in Two Blackwater Rivers of Southern Venezuela

We investigated the ecology of peacock cichlids (Cichla spp.), diurnal piscovores and important gamefishes, in the Rio Cinaruco (Rio Orinoco drainage of the southern Venezuelan llanos) during the dry seasons of 1992-1993 and the Rio Pasimoni (Rio Negro-Amazonas drainage) during early 1993. In the Cinaruco, three Cichla species partitioned available habitats: C. intermedin near structure in primary river channel within or near swift current, C. orinocensis in shallow water along the shoreline of lagoons or slow channel reaches, and C. temensis in deeper waters along sandbanks and steeper rocky banks of lagoons and the river channel. During the dry season, C. orinocensis and C. temensis fed heavily on small characiform fishes, and C. intermedin consumed a variety of fishes, including loricariid catfishes. Only two peacock cichlids, C. orinocensis and C. temensis, were found in the Pasimoni, a more acidic and less seasonal ecosystem. These two species were larger in the Pasimoni compared with Cinaruco conspecifics; however, conspecifics from the two locations conformed to similar mass-length relationships. In both river systems, C. temensis were significantly larger than congeners, and C. temensis consumed larger prey than congeners in the Cinaruco. Examination of gonads and sizes of intraovarian oocytes indicated that reproduction by all five populations probably is initiated during the late low water period and may continue into the flooding period. Investigamos la ecologia de los pavones (Cichlidae, genero Cichla), picivores diurnos importantes en la pesca deportiva, en el Rio Cinaruco (cuenca del Rio Orinoco en el sur del estado Apure, Venezuela) durante la sequia de los alios 1992-1993, y del Rio Pasimoni (cuenca Rio Amazonas, estado Amazonas) de Venezuela durante los primeros meses del 1993. En el Cinaruco, tres especies de Cichla reparten los habitat disponibles: C. intermedin se ubica cerca de cobertura (arboles sumergidas, etc.) en el cauce principal cerca 0 dentro de la corriente rapida; C orinocensis se

Gross Morphology and Configuration of Digestive Tracts of Cichlidae (Teleostei, Perciformes): Phylogenetic and Functional , Significance

The gross morphology of cichlid digestive tracts is investigated in 71 African, Neotropical and Asian species with differing food preferences and body shapes. Eight other perciform families are included for outgroup comparison. The ontogeny of the digestive tract is investigated in four cichlid species. The arrangement of the digestive tract of cichlids is unique among all fishes examined hitherto: the stomach's extendible blind pouch, the left hand exit to the anterior intestine and the first intestinal loop at the left side. This corroborates the monophyly of the family. The length of cichlid intestines and their concomitant coiling types appear to depend upon food preference: piscivorous, paedophagous and crustacean eating species have simple and short intestines, whilst phytophagous, insectivorous, detritivorous, zoo- and phytoplanktivorous forms are characterized by long intestines. The intestinal length of the different molluscivorous species examined depends on the amount of detritus in the diet. The possible adaptive significance of intestinal lengthening is discussed and three different ways of intestinal arrangement are defined. The digestive tracts of the African genera Haplochromis, Hoplotilapia, Platytaeniodus, Astatoreochromis, Macropleurodus, Pseudotropheus, Melanochromis, Cyrtocara, Petrotilapia, Au lonocara, Labeotropheus, Pelvicachromis and Sarotherodon are characterized by a typical dorsal intestinal flap-back-loop. This loop is lacking in the west African genus Hemi chromis, in all Neotropical cichlids and in all outgroup taxa examined and as such appears to be of possible phyletic significance.