Influence of carbon tetrachloride on the liver of tadpoles of brown frog (Rana temporaria) [Translation from: Trudy leningt.sanit.-gig.med.Inst. 82, 32-36, 1967]

Comparative studies of the structure and regeneration of tissues in different vertebrates make it possible to get ideas from the evolution and regeneration potential of tissues. In this study are considered the reactive changes in the liver of larvae of the amphibian Rana temporaria to CC14 of different concentrations. Tadpoles of different sizes and different growth were placed once each day every day in a vessel with a determined solution of CC14 in water. The liver of tadpoles has a distinctive structure. It is distinguished by structure not only from the liver of higher vertebrates, but also from the liver of the adult frogs. The liver of the latter has an insignificant amount of fat and a whole series of other characters not typical of the liver of the tadpole. Placing the tadpoles in a solution of CCl4 with a concentration of 0.1% did not produce in the liver noticeable morphological changes. The author concludes that the absence of degenerative changes in the liver tadpoles, in spite of a high percentage of death of the experimental animals, tells of the well-known resistance of their liver to the influence of CC14.

Predation by Channa striatus (Bloch) on Rana tigrina (Daudin), Puntius gonionotus (Bleekeer) and Labeo rohita (Hamilton) in the laboratory

The growth performance of a predatory snakehead, Channa striatus was tested by supplying tadpoles of Rana tigrina and fingerlings of Puntius gonionotus and Labeo rohita as prey for a period of 21 days in aquaria. Prey consumption by C. striatus was significantly different (P<0.05) for different prey used (T1 - R. tigrina, T2 - P. gonionotus, T3 - L. rohita). Tadpoles of R. tigrina were preferred by the predator (C. striatus) over P. gonionotus and L. rohita although tadpole is nutritionally inferior to each of P. gonionotus and L. rohita. Each predator rayed on 50-330 mg per day per g of their body weight. Fish preyed on tadpoles also showed the highest growth. Significant difference in weight gain was found between T1 and T2 and also between T1 and T3 but no difference was found between T2 and T3. Food conversion ratio (FCR) was found to be lowest in treatment T3 followed by the treatments T2 and T1 respectively.

Size composition of catches of Yellowfin tuna in the Japanese long-line fishery in the eastern tropical Pacific east of 130°W

ENGLISH (pgs. 267-283): In the spring of 1963, the senior author, who is a member of the staff of the Nankai Regional Fisheries Research. Laboratory, Fisheries Agency, Japanese Government, came to the Institute of Marine Resources of the University of California as a visiting investigator, bringing with him catch statistical data from the fishery in the eastern Pacific, which had been collected at the Nankai Regional Fisheries Research Laboratory (NRFRL) through September 1962, in order to conduct studies of these data in collaboration with the junior author, and with investigators of the InterAmerican Tropical Tuna Commission. A general review of the long-line fishery, based on the catch statistics of the commercial fishing fleet has been published by Suda and Schaefer (1965). In this paper we present an analysis of data respecting the size-composition of yellowfin tuna taken on long-line gear throughout the eastern Pacific between 1958 and 1962, and make some comparisons with data on size-composition of yellowfin tuna taken in the near-surface fishery, by bait boats and purse-seiners, in waters adjacent to the American coast. As has been shown by Suda and Schaefer (1965), the long-line fishery in the eastern Pacific is primarily directed toward the capture of bigeye tuna. However, considerable quantities of yellowfin tuna are also taken on this gear, and, in addition, there are substantial catches of albacore and of several species of spearfishes in some parts of the range of this fishery. Information respecting the catch rates of yellowfin tuna, and information respecting the size-composition of the stock of yellowfin tuna being exploited by the long-line fishery, is of particular interes~" because the yellowfin tuna population of the eastern Pacific is also subject to an intensive fishery by baitboats and purse-seiners which capture this species, together with skipjack, near the surface along the coast of the Americas, and around the outlying islands, in the region of California to northern Chile. SPANISH (pgs. 311-329): En la primavera de 1963, el autor principal, quien es miembro del personal del Nankai Regional Fisheries Research Laboratory, Fisheries Agency del gobierno japonés, vino al Institute of Marine Resources de la Universidad de California en calidad de investigador visitante y trajo consigo datos estadísticos de las capturas de la pesquería en el Pacífico oriental, que habían sido recolectados en el Nankai Regional Fisheries Research Laboratory (NRFRL) hasta septiembre de 1962, con el fin de hacer estudios de esos datos en colaboración con el coautor y con investigadores de la Comisión Interamericana del Atún Tropical. Una revisión general de la pesquería con palangre, basada sobre las estadísticas de captura de la flota pesquera comercial, ha sido publicada por Suda y Schaefer (1965). En este trabajo presentamos un análisis de los datos correspondientes a la composición de tamaños del atún aleta amarilla capturado con equipo palangrero en todo el Pacífico oriental, entre 1958 y 1962, y hacemos algunas comparaciones con los datos sobre la composición de tamaños del atún aleta amarilla cogido en la pesquería superficial cercana, por barcos de carnada y rederos en aguas adyacentes a la costa americana. Como ha sido demostrado por Suda y Schaefer (1965) la pesquería con palangre en el Pacífico oriental tiene como principal objeto la captura del atún ojo grande. Sin embargo, considerables cantidades de atún aleta amarilla son capturadas también por este equipo y, además, hay también considerables capturas de albacora y de diversas especies de peces-espada en algunas partes de la región que abarca esta pesquería. La información respecto a las tasas de captura del atún aleta amarilla, y la relativa a la composición de tamaños del stock de esta especie que explota la pesquería con palangre, es de particular interés, a causa de que la población de atún aleta amarilla del Pacífico oriental es también objeto de una pesca intensiva por barcos de carnada y rederos que capturan esta especie, junto con el barrilete, cerca de la superficie a 10 largo de la costa de las Américas y alrededor de las islas mar afuera, en la región desde California hasta el norte de Chile.

Schooling habits of yellowfin tuna (Neothunnus macropterus) and skipjack (Katsuwonus pelamis) in the Eastern Pacific Ocean, as indicated by purse seine catch records, 1946-1955

ENGLISH: These aspects of the schooling habits of the yellowfin and skipjack tuna may be investigated by means of the logbook records of the catches of individual sets of the nets of purse-seine vessels. For both purposes it must be assumed that a set is made, in each case, on a single school of fish. The study of school sizes based on these data requires the additional assumption either that the entire school is captured or that each set captures a constant fraction of the school upon which it is made. In this paper we report on the results of such investigations based on logbook records of the purse-seine fleet. SPANISH: Estos aspectos de los hábitos gregarios de los atunes aleta amarilla y barrilete pueden ser investigados a base de los registros de bitácora en que se anotan las pescas resultantes de cada una de las operaciones con la red de encierre que realizan los barcos rederos. Para ambos propósitos hay que suponer que las operaciones se efectúan, en cada caso, en un cardumen independiente. El estudio de los tamaños de los cardúmenes o manchas, a base de estos datos, requiere una suposición adicional: que el cardumen entero es capturado o, en su defecto, que en cada operación con la red se pesca una fracción constante de la mancha objeto de la pesca. En el presente artículo damos cuenta de los resultados de dichas investigaciones basadas en los registros de bitácora que lleva la flota de embarcaciones que utilizan redes de encierre. (PDF contains 47 pages.)

The Japanese longline fishery for tunas and billfishes in the Eastern Pacific Ocean east of 130°W, 1964-1966

ENGLISH: Catch and effort statistics from the Japanese longline fishery operating in the eastern Pacific Ocean east of 130°W, from 1964 through 1966, were examined to study the geographic distribution, trends in apparent abundance, sexual maturity, and size composition of the tunas and billfishes. Yellowfin and bigeye tuna are generally most abundant in the equatorial regions of the high seas between about 10°N and 20°S, but west of 95°W. The marlins are more coastal in distribution, usually occurring to the east, and to the north and south of the heavy concentration of tropical tunas. Sailfish tend to be associated with coastal areas also, whereas shortbill spearfish are more frequently captured on the high seas. Swordfish are found most abundantly in the coastal regions off northern Mexico, and off northern Peru and southern Ecuador. The albacore, a temperate-water species of tuna, is most abundant in the high-seas area of the southeastern Pacific, Trends in apparent abundance were measured by the hook-rate (i.e. catch per 100 hooks). Hook-rates for bigeye tuna have decreased from about 3.5 fish per 100 hooks in 1958 to about 1.1 fish per 100 hooks in 1966. During the same period, effort was increased substantially and total catch has decreased since 1963. It does not appear that increased effort will result in sustained increased catches of bigeye. Hook-rates for yellowfin tuna in recent years have decreased to about one third of their initial levels. The surface fishery for yellowfin in the eastern Pacific apparently affects recruitment to the longline fishery. Assuming that present conditions in the surface fishery do not change appreciably, increased effort in the longline fishery probably would not produce sustained increased catches, but might in fact result in reduced catch rates. Unlike the situation for the other tunas of the eastern Pacific, it appears that the albacore fishery east of 130°W is not having a marked effect on their abundance. Although a high degree of variability was observed in the hookrates for striped marlin, no obvious trends are evident. Catches have decreased slightly from 13,500 tons in 1964 to about 11,000 tons in 1966. Heavy fishing for sailfish began in 1964 with a hook-rate of 10.6 fish per 100 hooks; by 1966 it had dropped to 5.8. Catches of this species in the area of major concentration dropped from 329,900 fish in 1965 to 173,600 fish in 1966. This fishery has operated for too short a period of time to enable one to determine its effect on the sustainable yield. Length-frequency measurements and gonad samples from yellowfin and bigeye tunas collected in the eastern Pacific were analyzed to determine sexual maturity and growth characteristics. The results corroborate the findings of earlier investigators. SPANISH: Las estadísticas de captura y del esfuerzo de la pesca japonesa con palangre que maniobra en el Océano Pacífico oriental al este de los 130°W, desde 1964 hasta 1966, fueron examinadas para estudiar la distribución geográfica, las tendencias de la abundancia aparente, la madurez sexual y la composición de talla de los atunes y de los peces espada. Los atunes aleta amarilla y ojo grande son generalmente más abundantes en las regiones ecuatoriales de alta entre unos 10°N y 20°S, pero al oeste de los 95°W. Los marlines son costaneros en distribución, apareciendo habitualmente hacia el y hacia el norte y sur de la densa concentración de atunes tropicales. pez vela tiende a asociarse también con las áreas costaneras, mientras el pez aguja corta es capturado con más frecuencia en alta mar. Los peces espada se encuentran más abundantemente en las regiones costaneras de México septentrional y frente al norte del Perú y del Ecuador meridional. La albacora, una especie de atún de aguas templadas, es más abundante en el área de alta mar del Pacífico sudoriental. Las tendencias en la abundancia aparente fueron evaluadas por la tasa de captura por anzuelo (i.e., captura por 100 anzuelos). Las tasas de captura por anzuelo del atún ojo grande, disminuyeron en 1958, de unos 3.5 peces por 100 anzuelos a cerca de 1.1 pez por 100 anzuelos en 1966. Durante el mismo período, el esfuerzo fue aumentado substancialmente y, desde 1963, la captura total disminuyó. No parece que el aumento del esfuerzo resultara en un aumento sostenido de las capturas del atún ojo grande. Las tasas de captura por anzuelo de atún aleta amarilla han disminuido en un tercio de los niveles iniciales, en años recientes. La pesca de superficie de esta especie en el Pacífico oriental afectó aparentemente el reclutamiento en la pesca con palangre. Suponiendo que las condiciones actuales de la pesquería no cambien apreciablemente, un aumento del esfuerzo en la pesquería palangrera probablemente no produciría un aumento sostenido de las capturas, pero en realidad podría resultar en tasas de captura reducidas. A diferencia de la situación de otros túnidos del Pacífico oriental, parece que la pesca de la albacora al este de los 130°W no ha tenido un efecto marcado en su abundancia. Aunque se observó un alto grado de variabilidad en las tasas de captura por anzuelo correspondientes al marlin rayado, no fueron evidentes tendencias obvias. Las capturas han mermado ligeramente de 13,500 toneladas en 1964 a unas 11,000 toneladas en 1966. La fuerte pesca por peces vela empezó en 1964 con una tasa por anzuelo de 10.6 peces por 100 anzuelos; en 1966 había mermado a 5.8. Las capturas de esta especie en el área de mayor concentración disminuyeron de 329,000 peces en 1965, a 173,600 peces en 1966. Esta pesquería ha maniobrado por un período demasiado corto de tiempo para que pueda determinarse su efecto en el rendimiento sostenible. Las mediciones frecuencia-longitud, y las muestras de las gónadas de los atunes aleta amarilla y ojo grande, obtenidas en el Pacífico oriental, fueron analizadas para determinar la madurez sexual y las características del crecimiento. Los resultados corroboraron los hallazgos anteriores de investigadores. (PDF contains 144 pages.)

Preliminary studies on hypophysation technique of induced breeding of Clarias lazera

Fry supply is still the most serious problem yet to be solved in the culture of Clarias lazera in ponds. The object of the experiment is to compare the effect of fresh pituitary extract with that of the synthetic hormone with a view to determining the dosage. Ten trial runs were made using either the fresh pituitary extract of the human chorionic gonadotropin (HCG) at various concentrations. It was however, noted that the response of a particular set varies with the concentration. The actual result achieved from each set is highlighted under each experiment

Investment prospects in the production of the common carp (Cyprinus carpio) fingerlings in freshwater ponds

Since the introduction of Common carp Cyprinus carpio in Oyo State (Nigeria) from Israel in 1964, various local breeding methods have been employed in carp rearing to improve the survival rate at all stages of development during breeding. The physico-chemical parameters of the ponds which were simultaneously investigated for carp rearing in this study includes temperature (t), dissolved oxygen (DO) and hydrogen-ion concentration (pH). However, high rates of water displacement in the breeding ponds were unfavourable to the development of zooplankton which play important role in the food web of C. carpio. The survival rates of 15.88-69.50% and 19.60-33.83% obtained for the egg-hatchling and hatchling-fingerling stages respectively were encouraging. A breeding performance of this magnitude was found to be viable, breaking even in the fourth year. However, an increase in size of this trial project would be more profitable and increase fingerling supply as well as provide employment opportunities. This study thereby provides some baseline information on some local techniques and progress in the propagation of C. carpio and scope for further improvement

Utilization of non-piscine pituitary extract in the breeding of Clarias gariepinus

The use of synthetic and non-synthetic hormones have been reported in different regions with the recommendation of different doses. The adaptability of these findings have however not been very successful due to the high cost of building and maintaining hatchery, high cost of synthetic hormone (when available) and high level manpower required. It is obvious that adaptive research in the past ten years in developing countries like Nigeria have been geared towards utilization of resources that are equally effective but cheap and ready to come by. This paper reports the utilization of the pituitary extract of bull frog (Rana adspersa) and the toad (Bufo regularis) in the induced breeding of the African catfish, Clarias gariepinus. The extraction and dosage are discussed alongside the preliminary rearing of fries in outdoor hatchery tanks. Human chorionic gonadotrophin (HCG) and Clarias pituitary extracts were used as control

Creation of temporary ponds for amphibians in northern and central Europe

More than 4000 ponds have been created or restored in Denmark since 1985 as part of a large-scale pond-digging programme to protect endangered amphibians in particular and pond flora and fauna in general. Most ponds are created on private land with public financing. The programme was triggered by, among other factors, a drastic decline in amphibian populations in Denmark between 1940 and 1980. However, in recent years there has been an increased awareness in Denmark that temporary ponds are important for the conservation of some of the most rare amphibian species, such as fire-bellied toad Bombina bombina, natterjack toad Bufo calamita and green toad Bufo viridis. Other rare species such as moor frog Rana arvalis and European tree frog Hyla arborea also benefit from temporary ponds. The last 15 years of work on the conservation of endangered species and their habitats has resulted in a last-minute rescue and a subsequent growth in the size of most Danish populations of fire-bellied toad and green toad; some populations of the relatively more common natterjack toad have also increased. The creation of temporary ponds plays an important role in the success of these three species. The creation of ponds to help restore viable populations of the most rare amphibians has not been easy. To study the conditions that may need to be created, Danish herpetologists searched for areas with temporary ponds that had good water quality, natural hydrological conditions and a management regime influenced by traditional agricultural methods. The paper gives an overview of pond creation and restoration projects in Denmark and Poland and their significance for amphibian diversity.

Soil quality of Bhilwara District (Rajasthan) in relation to pisciculture

The present paper deals with the physico-chemical data of 13 rainfed and drainable dry bundhs of Bhilwara District (India). All the dry bundhs studied showed a slightly alkaline pH ranging from 7.5 to 8.5. Electrical conductivity ranged from 2 to 8 millimhos/cm. Organic carbon in sediment fluctuated from 0.30 to 0.75%. Nitrogen, phosphate and potassium levels were fairly good, at 30 to 50 and 24 to 36 mg/100 g of soil respectively. Based on these data it was inferred that these dry bundhs were highly productive and suitable for freshwater fish culture.

Malaysian school engages in bullfrog and turtle farming

A brief description is given of the culture methods used in the Sepang Today Aquaculture Centre, a private aquafarming training school in Malaysia, regarding American bullfrog (Rana catesbeiana) and the soft-shelled turtle (Trionyx sinensis). Seed production, grow-out, marketing and future potential are discussed, referring to the school s training brochures for both culture methods.