The Aquatic Commons is a thematic digital repository covering the natural marine, estuarine /brackish and fresh water environments . It includes all aspects of the science, technology, management and conservation of these environments, their organisms and resources, and the economic, sociological and legal aspects.
Subject = Biology
Mostrando recursos 1 - 20 de 5,554
A key to the families and genera of freshwater fishes of Tanzania - Matthes, H.
The purpose of this key is to facilitate rapid and accurate identification, in the field, for fisheries workers. It is therefore based as much as possible on external
characters only and an attempt has been made to keep it simple and straight forward. The only real difficulty arises in clearly demarcating the numerous cichlid
genera of the great lakes, despite the fact that these have been treated in separate sections for each lake. Moreover, it hasn't been possible to revise the key to the lake
Nyasa genera (taken from Jackson, 1961) to any significant extent, my experience with L. Nyasa fishes being limited;...
La reproducción de la merluza en el Mar Argentino (Merlucciidae, Meluccius merluccius hubbsi) : 1. Descripción histológica del ciclo del ovario de merluza - Christiansen, H.E.
The present paper deals on the histological description of the hake ovary made on the basis of gonad observations of 394 females during the period April 1966 March 1967. The material was obtained from weekly sampling of commercial catches carried out at the Institute of Marine Biology (Prov. Buenos Aires, Argentina). The anatomical and histological description of the standard ovary and the adopted terminology are given. The maturation process is divided into five periods, from ovocyte formation to yolked ovocyte formation, with its histological description. Ovary changes are analyzed on detail. The following conclusions were outlined: 1. Analysis demonstrated that...
Taxonomía y distribución de los poliquetos pelágicos del Atlántico Sudoccidental - Orensanz, J.M.; Ramirez, F.C.
This work is based on the analysis of 420 planktonic samples of 7 oceanopraphic cruises distributed over the Argentine, Uruguayan and South brasilian continental shelf (SW Atlantic ocean), as well as from some oceanic sectors, adjacent to the continental slope. Vertical hauls were performed in all stations from 100 m depth to surface, except in the Walter Herwig cruise (where vertical hauls were predominantly performed out of slope sectors, between 300 and 500 m depth to surface) and Productividad cruise in which only surface waters were hauled. A list of 27 species are determined, corresponding to 5 families: Iospilidae (3...
Contribución al estudio biológico de Loligo brasiliensis Bl - Castellanos, Z.J.A. de
A total of 592 individuals of Loligo brasiliensis from the Mar del Plata coastal fishing area (Buenos Aires prov., Argentina) have been studied during the 1961-1964 period. From a morphological point of view the population appears to be uniform and homogeneus. A brief description of this species is given in this paper since references in the literature are scarce from the time at which Blainville (1923) first described it. The only further references are found in D'Orbigny (1835), and Ferrusac (1839), and in Hoyle (1886), and Tyron Pilsbry (1879). In this paper the species was mentioned only as a bibliographical...
Observaciones sobre la reproducción, desarrollo embrionario y larval de la anchoíta argentina (Engraulis anchoita) - Ciechomski, J.D.de
The first studies on the problems related to the reproduction of marine fish in Argentina (SW Atlantic ocean) have been carried out with a species of great economic importance, the anchovy (Engraulis anchoita Hubbs and Marini). The spawning period of this species during the period 1963-64 has been determined. By the application of the quantitative collection method, it has been established that spawning commenced in the areas close to the coast during the first few days of September and at a water temperature of 10,3° C and reached its greatest intensity in October (up 1569 eggs/1 square metre surface water)...
Contribución al conocimiento biológico del calamar argentino Illex illecebrosus argentinus - Castellanos, Z.J.A. de
The present work deals with the biological study of the squid Illex illecebrosus argentinus of the Buenos Aires area (Argentina) in the southwest Atlantic ocean. According to recent research (Voss, pers. comm.) the squid obtained in commercial fishing in the waters off Buenos Aires Province (Castellanos), which in proper of the S.W. Atlantic. The material studied comes from commercial fishing done in in two sectors: one ranging from 36~' to 37~' S, and the other from 39~' to 42~' S in latitude, while both extend from 55~' to 62~' W in longitude. The fishing area varies during the years, being...
La estructura y reproducción de Acanthococcus antarcticus Hooker et Harvey - Joly, A.B.; Cordeiro, M.; Yamaguishi, N.
The present paper gives a full description of the organization of Acanthococcus antarcticus Hooker et Harvey, a not well known member of the Rhodophyllidaceae as well as gives for the first time description of the male and tetrasporic plants. Detailed organization of the carpogonial branches, spermatia and tetraspores is also presented. Nineteen figures illustrate the text (material collected at Deseado port, Santa Cruz prov., Argentina). The following text is the content of the discussion. From the description it is possible to confirm the position of Acanthococcus in the Rhodophyllidaceac as was done by Kylin (Kylin 1960, p. 290 et seg.)....
El plancton de Mar del Plata durante el período 1961-1962 (Buenos Aires, Argentina) - Balech, E.
The first part presents a general picture of the composition of the coastal plankton near Mar del Plata (Buenos Aires prov., Argentina) between August 1961-August 1962. Especially noted is the abundance of Noctiluca from October to the end of March. The second part deals with the plankton collected during a short cruise, named Operación Mar del Plata 1, planned to survey coastal waters. In the third part the author gives the descriptions of some new or interesting species. A chain-forming Gymnodinium is reported as G. catenatum; some differences with Graham description, could be due to the fact that he studied...
Los camarones comerciales de la familia Penaeidae de la costa atlántica de América del Sur. Clave para el reconocimiento de las especies y datos bioecológicos - Boschi, E. E.
Este estudio está orientado a identificar correctamente las especies comerciales, evitar los errores que surgen como consecuencia de confundir las especies en los muestreos utilizador en los trabajos de bioestadística y por ende en la estimación del efectivo de las poblaciones. Los peneidos comerciales del litoral Atlántico de Sudamérica son fáciles de reconocer, con excepción de los representantes del género Penaeus, que en algunos casos puede ofrecer ciertas dificultades debido a la similitud en la morfología externa. Se espera que este estudio sea una contribución útil a biólogos pesqueros, pescadores y técnicos que tienen una actividad relacionada con la pesca....
La familia Podolampacea (Dinoflagellata) - Balech, E.
Este estudio tiene como finalidad dar a conocer la tabulación de los géneros Blepharocysta y Podolampas, hacer un estudio detallado de sus especies, contribuir al conocimiento de la distribución geográfica, sentar las bases para establecer sus relaciones filogenéticas con otros dinoflagelados y probar la unidad de la familia. Este trabajo constituye una revisión completa de todas las especies conocidas.
Improved facilities for marine biology in East Africa - Hartnoll, R.G.
In 1967 the then University College of Dar es Salaam built a small laboratory on the shore at Kunduchi, 16 km from the
main campus and 24 km north of Dar es Salaam. This was used for undergraduate field courses, and as a base for staff from the University to carry out research. It soon
became apparent that the urgent need for studies of the marine environment in the East African area, and the lack of existing facilities, necessitated the development of the Kunduchi Marine Biology station into a research establishment with its own staff of full time scientists. This operation began...
Marine Vertebrates and Low Frequency Sound: Technical Report for LFA EIS - Croll, Donald A.; Tershy, Bernie R.; Acevedo, Alejandro; Levin, Phil
Over the past 50 years, economic and technological developments have dramatically increased the human contribution to ambient noise in the ocean. The dominant frequencies of most human-made noise in the ocean is in the low-frequency range (defined as sound energy below 1000Hz), and low-frequency sound (LFS) may travel great distances in the ocean due to the unique propagation characteristics of the deep ocean (Munk et al. 1989). For example, in the Northern Hemisphere oceans low-frequency ambient noise levels have increased by as much as 10 dB during the period from 1950 to 1975 (Urick 1986; review by NRC 1994). Shipping...
Estimates of cetacean abundance in the northern Gulf of Mexico from vessel surveys - Hansen, Larry J.; Mullin, Keith D.; Roden, Carol L.
The Southeast Fisheries Science Center (SEFSC) initiated annual, vessel-based visual sampling surveys of northern Gulf of Mexico marine mammals in 1990. The primary goal of these surveys was to meet Marine Mammal Protection Act requirements for estimating abundance and monitoring trends of marine mammal stocks in United States waters. The surveys were designed to collect: 1) marine mammal sighting data to estimate abundance and to determine distribution and diversity; and 2) environmental data to evaluate factors which may affect the distribution, abundance and diversity of marine mammals. The analyses for abundance estimation from the 1991-1994 surveys are presented in this...
Preliminary estimates of cetacean abundance in the northern Gulf of Mexico, and of selected cetacean species in the U.S. Atlantic Exclusive Economic Zone from vessel surveys - Hansen, Larry J.; Mullin, Keith D.; Roden, Carol L.
The Southeast Fisheries Science Center (SEFSC) initiated annual, vessel-based visual sampling surveys of northern Gulf of Mexico marine mammals in 1990 and conducted a similar survey in U.S. Atlantic Exclusive Economic Zone (EEZ) waters from Miami, Florida, to Cape Hatteras, North Carolina, in 1992. The primary goal of these surveys was to meet Marine Mammal Protection Act requirements for estimating abundance and monitoring trends of marine mammal stocks in United States waters. The surveys were designed to collect: 1) marine mammal sighting data to estimate abundance and to determine distribution and diversity; and 2) environmental data to evaluate factors which...
Observations on the taxonomy and biology of Lates (Cuvier 1828) in Lake Albert - Hunter, J.B.
Both in terms of commercial landings and biological importance, the Nile Perch is one of the most prominent fish in Lake Albert. It can bear considerable further exploitation, is the source of stockings elsewhere, and it is, therefore, important to know whether more than one species is being dealt with, and, if so, what differences there are in the ecology of the different species.