Cruise 8 of the N.B. Scofield for 1956. Cruise Report 56-S-8

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Cruise 57-S-1 of the N.B. Scofield

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Cruise 3 of the N.B. Scofield for 1957.

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Pre-Cruise Plan N.B. Scofield Cruise 66-S-6

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Cruise 4 of the M/V N.B. Scofield for 1957.

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Cruise 5 of the N.B. Scofield for 1957.

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Cruise Report 64-S-6: N. B. Scofield, September 29 to October 25, 1964

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A quantitative analysis of the phytoplankton of the Gulf of Panama: I. Results of the regional phytoplankton surveys during July and November 1957 and March 1958

ENGLISH: 1. Quantitative phytoplankton samples were collected by the Inter-American Tropical Tuna Commission at the surface and ten meters in the Gulf of Panama, as follows: a) 18-21 March, 1958 (31 stations)-during the height of the upwelling season, b) 10-12 July, 1957 (10 stations)-during the transition to the rainy season at a time when mild upwelling winds reappear, c) 7-8 November, 1957 (15 stations)-during the height of the rainy season. 2. Maximum phytoplankton populations occurred during the upwelling season, followed by a considerable decline during July, and a further Subsidence during November. 3. A remarkable regional uniformity in species composition was observed during the surveys despite regional differences in growth conditions. Diatoms overwhelmingly dominated the communities. 4. During all surveys, the innermost regions, generally north of 8°30'N, were the most productive. The least productive areas were in the offing of San Miguel Bay and Parita Bay, suggesting that nutrient accretion via runoff is inadequate to sustain sizeable autotrophic plant populations in those regions. 5. During all surveys, phytoplankton growth appeared to be limited by nutrient availability. 6. During all surveys, phytoplankton growth appeared to be related to depth of the water column. 7. Although below average rainfall contributed to unusually favorable growth conditions (reduced stability, increased transparency and, presumably, nutrient reserves) during the November survey relative to November 1955 and 1956 at 8°45'N, 79°23'W, the anticipated heightened phytoplankton response was not observed. 8. During the November survey, the local diatom responses and their regional fluctuations could be satisfactorily related to the accompanying surface salinity conditions. However, this correspondence is undoubtedly attributable to factors associated with the observed salinity levels, probably nutrients, rather than salinity directly. 9. Unusually warm conditions occurred during the March survey, attributable to considerably weaker upwelling winds than normally occurring then, which contributed to a considerably lower standing crop and a retardation in succession of three to five weeks relative to that observed during 1955-1957 at 8°45'N, 79°23'W in the Gulf of Panama. 10. During the March survey, a well defined inverse relationship existed between mean temperature and mean diatom abundance in the upper ten meters, and between transparency and mean diatom abundance. A direct relationship occurred between surface salinity and mean diatom abundance in the upper ten meters. These relationships are interpreted to indicate that diatom abundance primarily reflected the nutrient concentrations associated with a given upwelling intensity, rather than describing casual relationships. 11. The survey results indicate that the phytoplankton dynamics observed at 8°45'N, 79°23'W from November, 1954 through May, 1957 are generally representative of the Gulf of Panama. 12. The following new forms, to be described in a later publication, were observed during the surveys: Actinoptychus undulatus f. catenata n.f., Asterionella japonica f. tropicum n.f., Leptocylindrus maximus n. sp., Skeletonema costatum f. tropicum n.f. SPANISH: 1. La Comisión Interamericana del Atun Tropical recolectó en el Golfo de Panama muestras cuantitativas de fitoplancton en la superficie y a los diez metros, como sigue: a) Del 18 al 21 de marzo de 1958 (31 estaciones)-durante el maximum de la estación de afloramiento. b) Del 10 al 12 de julio de 1957 (10 estaciones)-durante la epóca de transición a la estación lluviosa cuando reaparecen los vientos ligeros que causan el afloramiento. c) Del 7 al 8 de noviembre de 1957 (15 estaciones)-durante el maximum de la estación lluviosa. 2. Las poblaciones maximas de fitoplancton aparecieron durante la estación de afloramiento, seguido por una considerable disminución durante el mes de julio y una calma durante noviembre. 3. Durante la investigación se observó una remarcable uniformidad regional en la composición de las especies a pesar de las diferencias regionales en las condiciones de crecimiento. Las diatomeas predominaban en gran numero en las comunidades. 4. Durante todas las investigaciones, las regiones mas cerca de la costa, generalmente al norte de los 8°30'N, eran las mas productivas. Las areas menos productivas fueron las mar afuera de las Bahias de San Miguel y Parita, lo que sugiere que el aumento en las sales nutritivas causado por las escorrentias es inadecuado para sostener poblaciones grandes de plantas autotróficas en estas regiones. 5. Durante todas las investigaciones, el crecimiento del fitoplancton parecio estar limitado por la disponibilidad de las. sales nutritivas. 6. Durante todas las investigaciones el crecimiento del fitoplancton parecio estar relacionado con la profundidad de la columna de agua. 7. Aunque las precipitacion por debajo del promedio normal contribuyo a condiciones desusadamente favorables de crecimiento (estabilidad reducida, aumento de la transparencia y, presumiblemente, de la reserva de sales nutritivas) durante la investigación de noviembre en relación a noviembre de 1955 y de 1956 en los 8°45'N, 79°23'W, no se observo-la alta reacción de fitoplancton que se esperaba. 8. Durante la investigación de noviembre, las reacciones locales de las diatomeas y sus fluctuaciones regionales pudieron relacionarse en forma satisfactoria con condiciones asociadas con la salinidad de la superficie. Sin embargo, esta correspondencia puede atribuirse sin duda a factores asociados con los niveles observados de salinidad, probablemente con las sales nutritivas, en lugar de directamente con la salinidad. 9. Condiciones calurosas no comunes ocurrieron durante la investigación de marzo, las que pueden atribuirse a que los vientos que ocasionan el afloramiento fueran mas debiles que los normales, lo que contribuyó a que la cosecha estable fuera considerablemente mas baja y a la demora de tres a cinco semanas en la sucecion relativa a la que se observó durante 1955-1957 en los 8°45'N, 8°23'W, en el Golfo de Panama. 10. Durante la investigación de marzo, existió una relación inversa bien definida entre la temperatura y la abundancia media de las diatomeas en los diez metros superiores, y entre la transparencia y la abundancia media de las diatomeas. Una relación directa ocurrio entre la salinidad de superficie y la abundancia media de las diatomeas en los diez metros superiores. Estas relaciones se interpretan como indicadoras de que la abundancia de diatomeas refleja primeramente las concentraciones de las sales nutritivas asociadas con una intensidad de afloramiento dada, en lugar de describir relaciones causales. 11. Los resultados de la investigacion indican que la dinamica del fitoplancton observada en los 8°45'N, 79°23'W, desde noviembre de 1954 a mayo de 1957, es generalmente representativa del Golfo de Panama. 12. Durante las investigaciones se observaron las siguientes formas nuevas, las que seran descritas en una publicación posterior: Actinoptychus undulatus f. catenata n.f., Asterionella japonica f. tropicum n.f., Leptocylindrus maximus n. sp., Skeletonema costatum f. tropicum n.f.

Results of abundance surveys of juvenile Atlantic and gulf Menhaden, Brevoortia tyrannus and B. patronus

The estuarine populations of juvenile Atlantic and gulf menhaden (Brevoortia tyrannus and B. patronus) were sampled during two-boat, surface-trawl, abundance surveys extensively conducted in the 1970s. Juvenile Atlantic menhaden were sampled in 39 estuarine streams along the U.S. Atlantic coast from northern Florida into Massachusetts. Juvenile gulf menhaden were sampled in 29 estuarine streams along the Gulf of Mexico from southeast Texas into western Florida. A stratified, two-stage, cluster sampling design was used. Annual estimates of relative juvenile abundance for each species of menhaden were obtained from catch-effort data from the surveys. There were no significant correlations, for either species, between the relative juvenile abundance estimates and fishery-dependent estimates of year-class strength. From 1972 to 1975, the relative abundance of juvenile Atlantic menhaden in north Atlantic estuaries decreased to near zero. (PDF file contains 22 pages.)

Comparative growth and survival of fry of Clarias gariepinus (B), Clarias anguillaris (L), Heterobranchus bidorsalis (G), Heteroclarias, Clariabranchus and Clarias hybrids under outdoor nursery management system

Hybrids of Clariid catfishes; C. gariepinus (Netherlands), C. anguillaris, H. bidorsalis and their parental species were monitored for 8 weeks in 2 x 2 x 1m outdoor concrete tanks. The fry were fed NIFFR diet (40% crude protein) twice daily, 7 days of the week. Growth and survival records were taken weekly. The male HEB X female CLG hybrid showed an overall highest performance in growth rate while the lowest was recorded in male CLA X female CLG hybrid. The male HEB X female CLG hybrid grew at a faster rate than its reciprocal hybrid. In view or their growth rate, it is possible that the growth and survival rates or H. bidorsalis especially at the fry to fingerling stage could be improved through hybridization. The hybrid have potential as commercial food fish

Experimente über die Wirkung von UV-B auf pelagische Fischembryonen in einem Sonnenscheinsimulator

One of the supposed effects of the observed ozone depletion is the increase of solar UV-B irradiation at the seasurface. This will cause an impact on certain compartments of marine ecosystems. Especially, sensitive developmental stages of pelagic fish embryos might be affected. Embryos of dab (Limanda limanda) and plaice (Pleuronectes plalessa) were experimentally exposed 10 different amounts of UVB irradiation in a sunshine simulator. This programmable device allows the dosage of realistic solar irradiation in quality and guantity. Experiments were carried out in March 1995 and February 1996. Either artificially inserninated and reared emhryos of dab and plaice or embryos caught in the German Bight were exposed to simulated solar irradiation. The 1995 experiments served to identify the effective irradiation dosages. For the 1996 experiments irradiation applied was much lower, being dose to realistic valucs expected over the North Sea as a consequence of ozone depletion. The following end points were studied: 1. Mortality, 2. sublethal morphological effects (malformations), 3. DNA damage, 4. changes in buoyancy of embryos measured as changes in osmolarity of the perivitelline fluid. Conditions for the simulation of daylight were a c1oudless sky with a solar zenith distance of 34 % (air mass 1.2). The adopted ozone depletion was 40 % corresponding to 180 DU (Dobson Units) instead of 300 DU. In the 1995 experiments time and dosage dependent influenccs on mortality and buoyancy of embryos of dab and plaice were found. Even in those embryos which were protected from the UV-B spectral range a loss of buoyancy was registered after 12 hours in the simulator. No diffcrences in DNA integrity as determined by DNA unwinding of exposed and control embryos were found. Also with lower amounts of irradiation in the 1996 experiments dosage dependent acute mortality, malformations, and impact on the buoyancy of the emhryos was registered. Sublethal effects occurred as well in embryos protected against UV-B in the exposure chambers, but were not found in the dark controls. The impact of low dosages of UV-B on the buoyancy of pelagic fish embryos might indicate an important ecological threat and deserves further studies.

On the population dynamics of Eudiaptomus gracilis Sars and Heterocope borealis Fischer in the Bodensee-Obersee. Part B. Eudiaptomus gracilis Sars. [Translation from: Trudy Instituta Biologii Vnutrennykh Vodnany 12(15) 170-174, 1966.]

Experimental research was conducted to study the development of eggs of Eudiaptomus gracilis Sars. The egg production was studied as well as the population dynamics. Factors like losses in the lake and through the effluent Rhine at Konstanz were considered.

A biologically active peptide in the skin of lampreys (Eudontomyzon danfordi vladykovi). [Translation from: Z.Naturforsch. (B), 26(10), 1021-1023, 1971. ]

In recent years interest in the production and description of kinin-type substances has been greatly intensified. So, for example, bradykinin, phyllokinin, physalaemin, ranatensin and caerulein could be extracted from the skin of amphibians as well as. eledoisin out of the salivary glands of Eledon moschata. An examination of lampreys seemed to us particularly profitable in the search for the incidence of further kinins. Ammocoetes of different sizes and also adults of both sexes of the species Eudontomyzon danfordi vladykovi were studied in this research. This species is found in many tributaries of the Danube. Skin extracts were tested on on isolated rat uterus, rat duodenum, guinea pig ileum and rabbit jejunum, further tests were done in order to determine a peptide character of the biologically active substance.

Consumption to biomass (Q/B) ratio and estimates of Q/B-predictor parameters for Caribbean fishes

Estimates of the Q/B ratio and parameters of equations to 'predict' Q/B values for 116 fish stocks in the Gulf of Salamanca, Colombia are presented. A compilation of these estimates available for Caribbean Sea fishes (264 stocks) is also provided for comparison purposes. General trends in the value of Q/B resulting from differences in the equation and parameter values used are briefly discussed.