Hybridization of Cyprinus carpio and Carassius auratus,the first two exotic species in the lower Laurentian Great Lakes

Synopsis A preliminary comparison of Cyprinus carpio × Carassius auratus hybrids with the parent species is made by means of hybrid indices for 29 morphometric and 19 meristic characters. Of these 48 characters 29 were intermediate, seven were identical with one of the parents and 12 were extreme. Marked osteological differences in the crania of the parent species were noted as possible diagnostic characters for the identification of hybrids.Note     

Horizontal cells of the carp retina: Golgi impregnation and Procion-Yellow injection

Summary Application of two methods for the selective staining of neurons, Golgi impregnation and intracellular marking with Procion Yellow, has revealed the anatomical arrangements of the horizontal cells in the carp retina. There are two basic horizontal-cell types, those with axons and these without. The former can be subdivided into three groups on the basis of the pattern of branching of the dendrites. These three structural groups are also functionally distinct, as shown by the electrical recordings made during Procion-Yellow injection. The axons of these three types of cell project into the proximal part of the inner nuclear layer, where they expand to form morphologically indistinguishable terminals. Fine horizontal processes leave the surfaces of these axon terminals. The functional behavior of a terminal resembles that of the associated soma. The horizontal cells lacking axons vary in morphological appearance, but they are similar functionally.This work was supported by the Deutsche Forschungsgemeinschaft     

Ultrastructural and histochemical investigation of the terminal capillaries in the spleen of the carp (Cyprinus carpio L.)

Summary In the spleen of the carp arterial capillaries of a highly differentiated structure have been studied by light and electron microscopy. These capillaries share various structural characteristics with the sheathed capillaries (ellipsoids of Schweigger-Seidel) of higher vertebrates. The long arterial capillaries of the carp spleen are provided with cuboidal endothelial cells containing filaments approximately 7 nm in diameter. There is no basal lamina. The endothelial cells form various types of cell junctions, but there are also extensive areas without any junctions. Here, a free passage is possible between the capillary lumen and the subendothelial space. The capillaries possess a single-layered sheath of macrophages. Characteristically, the sheath macrophages possess long and slender cell processes forming a loose framework, the meshes of which are filled with lymphocytes and spindle cells. The sheath macrophages show a zone of ectoplasm rich in filaments. They also contain numerous phagolysosomes rich in hydrolytic enzymes, as identified histochemically. The sheath is sharply limited against the pulp by a thick layer of collagen fibers.     

Temporal Pattern of Ovarian Activity in a Major Carp Catla catla and its Possible Environmental Correlate in an Annual Cycle

Histophysiological studies of the ovary in a hitherto unconsidered major carp Catla catla, included in this investigative treatise, have allowed the present investigators to demonstrate the pattern of annual events in ovarian functions, as well as the inter-relationship between changes in the ovary and environmental conditions. Month-wise studies of cytological features along with various biochemical features of ovarian functions in free-living Catla revealed the existence of precise annual cyclic changes. On the basis of the studies made on gonads, the annual breeding cycle of this fish has been divided into four different phases, namely (a) the preparatory phase (January-March), (b) the pre-spawning phase (April-June), (c) the spawning phase (July-August), and (d) the post-spawning phase (September-December). A detailed analysis of the data employing various exploratory data-analytic techniques was aimed at drawing a possible relationship between the indices of different reproductive events (oogenesis and oocyte maturation, vitellogenesis, steroidogenesis) in mature free-living female Catla and the different components of the environment in an annual cycle. The results of the study indicate that annual variations in photoperiod, alone or in association with water temperature, may be the major environmental component which plays a significant role in the regulation of seasonal maturation of ovary in Catla. These observations provided a basis for further experimental studies on the specific role of photoperiods in the regulation of ovarian activities in the currently considered most economically important species of Indian major carp.     

The influence of acclimation and experimental temperature on glutamate dehydrogenase of carp red lateral muscle (Cyprinus carpio L.)

The dependence of the reaction catalysed by carp red lateral muscle glutamate-dehydrogenase on acclimation and experimental temperature was studied. In addition to quantitative aspects of enzyme temperature compensation, the influence of temperature conditions on kinetic characteristics of the enzyme protein is reported. Results are discussed with respect to temperature capacity adaptation (acclimation).     

Studies on the fish-gill microclimate: interactions between gill tissue,mucus and water-quality

Synopsis Single gill filaments, isolated from carp and exposed to flowing water, produced mucous layers that filled the spaces between secondary lamellae. Filaments, removed from fish acclimated to either tap water or to ion-poor water, were exposed either to acclimation water or to acidified acclimation water with added aluminium. Ion-selective microelectrodes and 3 M KCl electrodes were used to measure conditions at the filament surface and within the filament's efferent filament artery. Isolated filaments maintained a constant transepithelial potential difference but internal pH and sodium concentration were less stable in some water qualities. Surface accessibility for microciimate analysis, however, was excellent. Small gradients of Na⁺ and more substantial gradients of pH were found in ion-poor water and in acidified water qualities, respectively. Mucus is thought to contribute to these gradients by providing an unstirred layer between gill tissue and external water. The filament microclimate was only slightly dependent on the ion-exchange properties of mucus and these were only marginally and unpredictably influenced by water quality.     

Ecological fish production in Long Pond,a lakeshore lagoon on Long Point,Lake Erie

Synopsis Long Pond, a recently formed 2.4 ha lagoon on Long Point, Lake Erie (Canada), was treated with piscicide and found to contain 47,768 fishes of 22 species. Nine dominant species (Notropis heterolepis, Pimephales notatus, Notemigonus crysoleucas, Lepomis gibbosus, L. macrochirus, Perca flavescens, Cyprinus carpio, Micropeterus salmoides and Carassius auratus) comprised 91% and 97% of total numbers and standing crop respectively. Age, growth and production were determined giving a total fish production estimate (corrected for all species) of 87.5 kg ha^–1 y^–1 for this lagoon. Dominant species were deemed either invaders (Cyprinus carpio, Carassius auratus), which had entered the lagoon to spawn and been trapped, or residents. The invaders comprised 82% of the 277.8 kg ha^–1 total standing crop. Their successful spawning and subsequent escape of the young from the lagoon would have resulted in some 615 kg y^–1 of fish production outside the lagoon. Resident stocks were dominated by young fishes, a characteristic of exploitation or early colonization. This may have been due to the recent formation and subsequent expansion of the lagoon or high annual mortality due to extreme physical conditions but was most likely the result of excessive predation by Micropterus salmoides. Relationship between biomass and production show that the chance inclusion of the invaders produces an immediate shift from a characteristically early to a characteristically late phase of ecological development.     

A new breeding system using gynogenesis and sex-reversal for fast inbreeding in carp

Summary A new breeding technique is demonstrated using gynogenesis and sex-reversal. The essence of this method is an adequate alternation of gynogenesis and sibmating with a maximal increase in the coefficient of inbreeding. The rate of this increase considerably exceeds that characteristic of sibmating. The change in the coefficient of inbreeding (F) and in the degree of genotypic identity (I) were determined in the carp in which 9 recombination probabilities are known. In the GS system the value of F exceeds 0.9 in the fifth generation, increasing above 0.99 while in the 12th generation.     

Saline acclimation of striped mojarra <Emphasis Type="Italic">Eugerres plumieri</Emphasis> (Cuvier 1830) and optimal dosage of carp pituitary extract (CPE) to induce spawning

The main objective of the current study was to determine an optimal dosage of commercial carp pituitary extract (CPE) of the conventional heteroplastic hypophysation technique to induce spawning in the wild caught striped mojarra broodstock Eugerres plumieri under laboratory conditions. We also describe trials testing saline acclimation regimes (changes from 10‰ to 30‰) prior to hormonal induction. For saline acclimation, three treatments were performed: first and second treatments began 1-day after conditioning of broodstock fish with a total duration of the saline changes lasting 1-day and 2-days, respectively. The third treatment began 30-days after conditioning with a 7-day saline regime. After reaching 30‰, all fish from the first and second treatments died after the fourth and ninth days, respectively; while the fishes in the third treatment survived more than two years. These fish remain on public exhibit in the “Mundo Marino” Aquarium, Santa Marta, Colombia. Four treatments of hormonal induction were tested on females using a total concentration of 5-mg of CPE per kg of body weight: first, second and third treatments were applied in two hormonal doses that corresponded to 10%–90%, 30%–70% and 40%–60%, respectively, with time intervals between doses of 14-h for the first and second treatment and of 12-h for the third treatment. The fourth treatment was applied in four hormonal doses that it corresponded to 20%–20%–30%–30% with 12-h time intervals between doses. Only the fishes of the fourth treatment resisted the induction, continued to live and reached spawning artificially. Water temperature remained at 28 ± 1°C and at 30‰ salinity during the study. The “dry” method of fertilization was used. The fertilized eggs were incubated at 30‰ and 35‰ salinities. These eggs reached the Morula early stage, but were later attacked by protozoan. These results suggest that fast changes of saline and limited hormonal dosages do not offer effective results in Eugerres plumieri. This work provided fundamental procedures for the culture and maintenance of live broodstock for striped mojarra in saltwater and/or coastal lagoon habitats and provides an effective and viable dosage of CPE for artificial spawning and commercial production in this species.