Age and growth of the duckbill catfish (Sorubim cf. lima) in the Pantanal.

The Duckbill Catfish, Sorubim lima, is a predator of large South American rivers. The age and growth of S. lima were studied based on the pectoral fin-spines of samples collected from the Cuiabá River, Pantanal. The samples were taken from commercial and experimental hook-and-line fishing. An analysis of the marginal increment suggests that the growth rings are formed once a year during the dry season, from July to September (ANOVA type I: F = 4.183; g.l. = 3 and 104; p = 0.008). The estimate of the parameters that describe von Bertalanffy's growth curve by nonlinear regression of the observed lengths in the age were: L infinity = 56.0 cm (fork length); k = 0.245 year-1; to = -2.605 years. The animals were estimated to have a life span of 9.6 years. The findings indicate that the fork length is a good predictor of the age of individuals of this fish species.     

Age and growth of the catfish Bagrus meridionalis Gunther in southern Lake Malawi

Vertebrae from 250 Bagrus meridionalis from the southern end of Lake Malawi were used for age and growth determinations. There is a close correlation between ages determined from length frequency data and ages obtained by back-calculation of the lengths when vertebral rings arc laid down. The rings are laid down annually, probably during the breeding season. Females grow slightly faster than males, the difference being in the order of 1–2 cm/year in the early stages. Recruitment to the trawl fishery takes place in the third year of life. Both sexes breed for the first time at the end of their fourth year. There is a much greater mortality in the male population after 40 cm in length.     

Age, growth and yield per recruit analysis of the pintado Pseudoplatystoma corruscans (Agassiz, 1829) in the Cuiabá River basin, Pantanal Matogrossense, Brazil.

The age and growth of the pintado Pseudoplatystoma corruscans were studied during the period from May 1994 to May 1995. The standard length ranged from 52 to 145 cm and the weight from 1.3 to 41 kg. The biometric relationship between the standard length (Ls) and total length (Ltotal) and between the total weight (Wt) and the standard length (Ls) were obtained for the species, being respectively: Ltotal = 3.296 + 1.069 * Ls and Wt = 0.00624 * Ls(3.134). The condition factor calculated monthly suggests the spawning season to be between the months of February and March. The age was estimated by counting growth rings present in the spines of the pectoral fins, and 10 age classes were detected. The mean distance of the last ring until the border of the spine suggests that the period of least growth is between July and September (dry period). Von Bertalaffy's equation describing the growth of the pintado is: Lt= 183 * [1 - exp - 0.085 * (t + 3.274)]. Total mortality was Z = 0.24 year(-1) and natural mortality M = 0.20 year(-1). As the present level of exploitation, F = Z - M = 0.04 year(-1), we conclude that the pintado stock was still underexploited in the Pantanal in the sampled period.     

Age and growth determinations in the catfish, Chrysichthys nigrodigitatus (Lacépède) by use of the dorsal spine

Annual rings on the first dorsal spine were used to determine the age and growth of the catfish, Chrysichthys nigrodigitatus (Lacépède), in the Lagos Lagoon, Nigeria. From back-calculations, it was found that the mean total length ofthe species when the first annulus was formed was 18.5 cm, 32.6 cm for second annulus, 43.5 cm for the third annulus and 53.9 cm for the fourth annulus. It was shown that this species in the Lagos Lagoon attained four years of age and that the fastest growth in length was achieved during the first year of life. Thereafter, increase in length gradually decreased with age. The relationship between the body length and dorsal spine radius was shown to be linear and highly correlated.     

Age and growth determination in a marine catfish using an otolith check technique

A direct and accurate method of age determination using the relative positions of otolith growth checks is described. In the catfish Guleichthys cuerulescens , otolith length and depth were both linearly related to fish length. Checks appeared to be formed twice per year, at the beginning and at the end of the rainy season (late June to late September). Growth was more rapid in the wet season, when water temperatures were at their height. Calculated mean fork lengths of spring-spawned fish after the first four years of life were respectively 11.5, 19.3, 26.3 and 33.1 cm. Few individuals grew beyond 40 cm, the survival of most of the population being five years or less, but a maximum recorded length of 51.5 cm suggested that catfish may occasionally persist into their seventh or eighth year. The shape of the growth curve indicated that, since a permanent seaward migration of older fish is unlikely, then natural mortality among lagoon-resident G. cuerulescens occurs before a growth asymptote is reached.     

Molecular systematics of the neotropical shovelnose catfish genus Pseudoplatystoma Bleeker 1862 based on nuclear and mtDNA markers

Pseudoplatystoma is a commercially important genus of Neotropical migratory catfishes widely distributed in all major river basins of South America. Historically, only three species were recognized, but a recent revision proposed eight putative morphospecies for the genus. A molecular study based on mitochondria DNA (mtDNA) provided support for recognition of only some of the species and raised questions about species boundaries in this group. We present a more encompassing analysis based on mtDNA (cytochrome b, 818bp) and nuclear DNA-based phylogenies (Rag1 intron 1, 664bp and S7 intron 1, 635bp) for a more extensive sampling (279 individuals from 42 localities) of all putative species in all major river basins. Patterns generated by individual gene genealogies and a multispecies coalescent analysis provided evidence to suggest recognition of only four distinct species in this genus: Pseudoplatystoma magdaleniatum, Pseudoplatystoma corruscans, Pseudoplatystoma tigrimun (sensu lato) and Pseudoplatystoma fasciatum (sensu lato). The species phylogeny places P. magdaleniatum as the sister group to all the other species in the genus, but the relationships among P. fasciatum s.l, P. tigrimum s.l., and P. corruscans could not be resolved with confidence.     

The amino-acid sequence of Northern Mallard (Anas platyrhynchos platyrhynchos) hemoglobin

The complete amino-acid sequence of the major hemoglobin component (HbA) of the adult Northern Mallard (Anas platyrhynchos platyrhynchos) is presented. A minor component HbD was also detected but in low concentrations. The sequences of alpha A- and beta-chains were established by automatic Edman degradation on tryptic peptides and peptides obtained by specific chemical cleavages. The alignment of the peptides was performed by comparison with the alpha A- and beta-chains of Greylag Goose hemoglobin (Anser anser). Thereby an exchange of five positions in the alpha A-chains and three in the beta-chains was observed. No exchanges were found in the surroundings of the heme, in alpha 1 beta 2-contact points, or allosteric regulatory sites. In the alpha 1 beta 1-subunit interface one amino-acid residue in alpha A-chains and one in beta-chains are exchanged. By comparison with the amino-acid sequence derived from globin genes of Domestic Duck (Anas platyrhynchos), the alpha A-chains differ by two exchanges in the N-terminal region and the beta-chains by five exchanges the in C-terminal region. The comparison of the amino-acid sequence derived from alpha A-globin gene of the Moscovy Duck (Cairina moschata) and alpha A-chains of the Northern Mallard, shows only one replacement.     

Retinohypothalamic pathway in the duck (Anas platyrhynchos)

Summary Retinohypothalamic connections were studied in the duck after unilateral optic nerve transection using both light and electron microscopic techniques. Degenerated endings of optic fibers were found only in a circumscribed part of the anterior hypothalamic area, i.e. the ventral region of the contralateral suprachiasmatic nucleus. Images of degenerating boutons were observed in frozen sections (method according to Johnstone-Bowsher), and their presence confirmed by electron microscopic examination. These degenerating boutons make synaptic contacts with dendrites or dendritic spines of neurons of the suprachiasmatic nucleus.In the same material, the decussation of the optic chiasma was studied with the light microscope. Uncrossed retinal fibers were found in the marginal optic tract, the basal optic root and occasionally also in the isthmo-optic tract.Dedicated to Professor Dr. W. Bargmann on the occasion of his 70th birthdaySupported by the DGRST and European Training Program Brain and Behaviour ResearchI wish to express my gratitude to Professor Andreas Oksche, who repeatedly offered me the scientific facilities at the Department of Anatomy of the University of Giessen, and who provided me with valuable neuroanatomical suggestions throughout the progress of these studies.     

Experimental inoculation of mallard ducks (Anas platyrhynchos platyrhynchos) with Borrelia burgdorferi

Birds have been incriminated as disseminaters of Borrelia burgdorferi and have the potential to spread the organism over a wide geographic range. Borrelia burgdorferi has been isolated from the liver and blood of passerine birds and from Ixodes dammini removed from passerines. The objective of this study was to determine if waterfowl, specifically mallards (Anas platyrhynchos platyrhynchos), were susceptible to infection with B. burgdorferi. Eight ducks were inoculated with B. burgdorferi; four orally and four intravenously (i.v.) and two ducks were inoculated with phosphate buffered saline as controls. All eight inoculated birds became infected and developed antibodies to B. burgdorferi. The spirochete was isolated from cloacal material from an orally infected duck on day 22 postinoculation (PI) and from an i.v. infected bird on day 29 PI, from the blood of an i.v. infected bird on day 7 PI, and from the kidney of an orally infected bird. Borrelia burgdorferi was detected by indirect immunofluorescence using the B. burgdorferi specific monoclonal antibody H5332 in kidneys of three orally infected birds and one i.v. infected bird and from the mesentery of one orally infected bird. These findings show that mallard ducks are susceptible to infection by B. burgdorferi and that they can be infected orally and shed the organism in the droppings. Thus, mallards could disseminate B. burgdorferi over long distances without the need of an arthropod vector.     

Bone typology and growth rate: testing and quantifying 'Amprino's rule' in the mallard (Anas platyrhynchos)

Periosteal bone histology expresses its rate of deposition. This fundamental relationship between bone structure and growth dynamics, first assumed by Amprino many decades ago, was quantified in preliminary studies, but never statistically tested. Moreover, the precise typological characters of bone tissue linked to growth rate remained poorly known. Here, we present the first statistical analysis of 'Amprino's rule', measured on comprehensive growth series of the mallard, Anas platyrhynchos. Growth rates were assessed by fluorescent labelling. Bone typology was described according to Ricqlès' typological classification. Results show that the presence and proportion of primary osteons, two consequences of bone initial porosity at the time of its deposit, are strongly related to bone growth rate. However, no significant relationship between primary osteons orientation and bone growth rate could be detected, at least for osteonal orientations (longitudinal, laminar and reticular) and growth rates values observed in mallard long bones. These results suggest that Amprino's rule holds for some major typological characters of primary compact bone tissues (i.e. primary osteons presence and proportion). However, it is irrelevant to some other characters (i.e. osteonal orientation), the meaning of which remains to be discovered.     

Molecular characterization of the insulin-like growth factor-I (IGF-I) gene in channel catfish (Ictalurus punctatus)

The insulin-like growth factor I (IGF-I) gene was characterized in channel catfish. Partial cDNA sequence, missing exon 1 and part of exon 2, was obtained in 5'- and 3'-RACE experiments. Direct sequencing of two bacterial artificial chromosome clones revealed gene structure and provided sequence from 640 bp upstream of the initiator methionine to 136 bp beyond the polyadenylation site. Genomic sequence contained a putative TATA box 506 bp upstream of the initiator methionine. The 477-bp reading frame within five exons encoded a 159-amino acid (aa) pre-propeptide highly similar to IGF-I in higher vertebrates. The sequence encoding the signal peptide was unique in catfish and contained 70% G+C content with the potential for a stable stem-loop structure. Full-length cDNA was only maintained in recombination-deficient (DH10B) strain E. coli. Levels of IGF-I mRNA were highest in liver, followed by brain and muscle, then heart and kidney (P<0.05). A CT/GA dinucleotide microsatellite in intron 1 was highly polymorphic in commercial channel catfish, and permitted placement of the IGF-I gene on the catfish genetic map. However, specific IGF-I alleles were not correlated with differences in growth rate from 100 to 130 days post-hatch in USDA103 line catfish.     

Precipitating antibodies of the duck (Anas platyrhynchos)

1. Ducks do not usually produce precipitating antibodies. However, when hyperimmunized with the dinitrophenyl (DNP)-human IgG (HIgG) conjugate, ducks made precipitating antibodies to the HIgG carrier, though not to the DNP hapten. 2. Precipitation did not require NaCl and occurred over a wide range of molarities and pH. 3. Antigenic and polyacrylamide gel analysis of affinity-purified antibodies, indicated that the major constituent of the antibody population was electrophoretically homogeneous 5.7S IgG. 4. The Ig heavy chains were in two populations, viz MW 37,000 and 41,000; non-precipitating duck 5.7S IgG antibodies to HIgG had only the MW 37,000 heavy chains. 5. It is suggested that duck precipitins belong to a previously unrecognized subclass of duck 5.7S IgG, with minor physical and antigenic differences from their non-precipitating counterparts.     

Description of the mallard duck (Anas platyrhynchos) karyotype

The karyotype of the mallard duck, Anas platyrhynchos, was characterised on the basis of R and C bands. Chromosomal preparations obtained from in vitro blood lymphocyte cultures were RBG- and CBG-stained. The structures of nine and 14 pairs of chromosomes were analysed by the RBG and CBG chromosome banding techniques, respectively. The location of R bands, as well as the size and arrangement of constitutive heterochromatin blocks were determined. Ideograms of R and C banded patterns of the analysed chromosomes were drawn. The morphological makeup of the analysed chromosomes was assessed.     

Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil.

Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolandia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerrad?o (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%) tabanids from 17 species were caught in the cerrad?o. The number of tabanid species varied from 7 during winter (July/August) to 15 in the spring (October). Tabanus importunus (56%) was the most abundant species, followed by T. occidentalis (8.2%), and T. claripennis (8.1%). The tabanid peak, in October, coincided with the beginning of the rainy season. The population peak of most species, including those with higher vector potential, suggests that the rainy season can be considered as the period of potentially higher risk of mechanical transmission of pathogens by tabanids to horses in the region.     

Age and growth of big skate (Raja binoculata) and longnose skate (R. rhina) in the Gulf of Alaska

In 2003, big skates, Raja binoculata, and longnose skates, Raja rhina, were the target of a commercial fishery around Kodiak Island in the Gulf of Alaska (GOA) for the first time. The sudden development of a fishery for these species prompted the need for improved life history information to better inform fishery managers. Due to the selective nature of the skate fishery, mostly larger individuals were captured. Back-calculation from skate vertebral measurements was used to estimate size-at-age for younger skates. Because back-calculated age-length data within individuals were highly correlated, bootstrap resampling methods were used to test for differences between male and female growth curves. Results from bootstrapping indicated that differences between male and female growth were statistically significant for both species. This investigation indicates that growth of big skates in the GOA (max size 178 cm total length, max age 15 years) is similar to that in California, but different from that in British Columbia. For longnose skates, our GOA results agree with those reported in British Columbia, but were considerably older (max size 130 cm, max age 25 years) than those reported in California, which may not be surprising because longnose skates in the present study were generally larger. This life history information suggests that both big and longnose skates are at risk of unsustainable exploitation by targeted fisheries.     

Chemical identification of catfish growth hormone and prolactin.

Isolation and primary structure of growth hormone (GH) and prolactin (PRL) from the pituitary gland of catfish (Ictalurus punctatus) are described. Alkaline extract of the pituitary glands was fractionated by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography on Octadecyl silica ODS. Catfish GH and PRL were identified by Western blotting with antisera against chum salmon GH and PRL. The catfish GH consists of 178 residues and is the most similar to carp GH, with sequence identity of 77%, although there is an uninterrupted deletion of 10 amino acid residues that corresponds to carp GH (90-99). The PRL is composed of 187 residues, which also exhibits the highest identity (79%) with carp PRL. Sequence identity between catfish GH and PRL is only 27%.