ALBERT

Description / Table of Contents: Summary Sodium dodecylbenzenesulfonate mixed to the diet for four weeks in a daily amount of 0,25 g/kg body weight increased the weight of the liver, and the fasting blood sugar level in rats. Sugar tolerance decreased. Detergent loading resulted in similar blood sugar curves than glucose loading.

Description / Table of Contents: Summary 5500 farm households are divided in several groups according to their main directions of production following the methodology described in part I (2) of this paper. The directions of production influence the food consumption as well as the calorie and nutrient intake and the requirement of the people living in farm households.

Description / Table of Contents: Zusammenfassung Die Aktivitäten von all-rac-α-Tocopherylacetat und 5 verschiedenen Tocopheraminen gegen Muskel-Dystrophie in Vitamin-E-defizienten Küken wurden bestimmt. Die molären Aktivitäten der Tocopheramine als Procent der molären Aktivität des all-rac-α-Tocopherylacetats waren wie unten angegeben: all-rac-α-Tocopheramin 100 all-rac-N-methyl-γ-Tocopheramin 87 all-rac-N, N-dimethyl-Tocopheramin 72 all-rac-δ-Tocopheramin 〈 5 all-rac-5,7-dimethyl-Tocamin 18

Description / Table of Contents: Zusammenfassung Tägliche Eingabe von 5 mg Phythylubichinon konnte die Entwicklung makroskopisch erkennbarer Muskeldystrophie (weißgestreifter Skelettmuskulatur) in Küken, die während 5 Wochen mit einer Vitamin-E-defizienten dystrophogenen Nahrung gefüttert wurden, nicht verhindern. Wenn unter den gleichen Umständen anstatt 5 mg Phythylubichinon, 1.5 mg α-Tocopherylacetat gegeben wurde, kam die Muskeldystrophie nicht zum Vorschein.

Description / Table of Contents: Zusammenfassung Gruppen von vierzig Rattenmännchen der „Charles River CD“ Zucht wurde eine hochgereinigte Nahrung verabreicht, die 20% Baumwollsamenöl, Olivenöl, Maisöl, Soyaöl, Hühnerfett, Rindsfett, Schweineschmalz oder gesättigte Triglyceride mittlerer Kettenlänge (MCT) enthielt. MCT wurde ohne Vorbehandlung, die anderen Fette entweder frisch oder nach vierzig stündigem Luftdurchblasen bei 60 °C verwendet. Gewicht, Überlebenszeit und histopathologische Veränderungen wurden beobachtet. Signifikante Unterschiede zwischen den Gruppen wurden beobachtet. Es erschien z. B. beachtenswert, daß die mit Hühnerfett ernährten Tiere eine erhöhte Zahl von myeloischen Leukaemien aufwiesen und daß die mit Pflanzenfetten ernährten Tiere besonders ausgeprägte myokardiale Veränderungen hatten. Da die Resultate nicht durch die Eigenschaften der Triglyceride erklärt werden konnten, muß man annehmen, daß Substanzen in der Nicht-Triglyceridefraktion von größter Bedeutung für die biologischen Unterschiede dieser Fette sind. Verbesserte Verfahren zur Herstellung von Nahrungsfetten sind zu empfehlen.

Description / Table of Contents: Summary Male Sprague Dawley rats were fed 0 or 250 mg/kg 5-hydroxymethylfurfural in their diet for 40 weeks. Weight gain, food consumption, and food efficiency were not influenced by HMF. The histological examination of liver, kidneys, heart, spleen and testes showed no abnormalities. After administration of 1 gr HMF to rabbits 12 mg of HMF were excreted in the urine. No metabolite could be detected in the urine. HMF was not oxidized by liver homogenates, mitochondria or supernatent. The oxidation of succinate and glutamate by liver mitochondria was not influenced by added HMF.

Description / Table of Contents: Summary 1. In aqueous phosphate buffer diacetyl tartaric acid monoglyceride is hydrolyzed to glyceride and tartaric acid. 2. Orally administered14C-labeled emulsifier to rats is absorbed to 26–31% of the activity given. 3. 21–20% are oxidized to14CO2, 8–13% are excreted in the urine, 2% are retained in the carcass.

Description / Table of Contents: Summary Some pharmacological effects were studied with HMF in a series of animal experiments. The LD 50 in mice was 0,751 g/kg body weight after i. v. administration and 0,842 g/kg after i. p. administration. No letal effects were seen however on oral administration up to 2 g/kg. 50, 100 and 200 mg/kg HMF given orally caused a dosage dependent vise in the spontanous activity and in the intestinal motility of mice as well as an increase in the bile flow of rats. HMF disappeared very quickly from the intestinal tract. In spite of this only traces could be recovered from the blood and urines. This seems to indicate that HMF is converted into biological active substances before absorption and that these substances are responsible for the biological effects.

Description / Table of Contents: Summary Virtually every mammalian tissue is capable of cholesterol synthesis, the highest synthetic activity is found in such tissues as liver and intestine. The daily cholesterol synthesis amounts to about 400–1100 mg, the daily turnover is 1000–1500 mg, the daily excretion 500–1000 mg. The daily dietary cholesterol exerts a limited influence on plasma cholesterol levels. Cholesterol is the precursor of bile acids, interruption of the enterohepatic circulation of bile acids will cause a disturbance of cholesterol metabolism. The most important of the factors regulating cholesterol metabolism so that relatively constant plasma levels are achieved is the limited absorption of cholesterol from the intestine.

Description / Table of Contents: Summary If sufficiently exact approximations for the zeroes of polynomials are present then numerical iterative methods yield sets of approximations for which the corresponding sets of absolute values of the functional values are monotonous decreasing. It is described by a twodimensional searching process, named “method of spiral course”, how to get such sets for arbitrary starting approaches. In this way we get direct methods, that is to say convergent methods for arbitrary approaches. The sets of approaching values are improved by extrapolation. ALGOL procedures and numerical results are given for a directNewton method and a direct third order method, which has a relationship to theMuller method. The treated methods also can be used for the evaluation of the zeroes of analytical functions.

Description / Table of Contents: Summary Using the natural structure of partially ordered vector spaces this paper presents a simple concept for studying existence and error bounds for solutions of nonlinear operator equations. In this context the theorem on iterative procedures in pseudometric spaces is (under a minor additional assumption) proved to be a special case of the theorem on contracting maps in metric spaces.

Description / Table of Contents: Summary The rate of convergence of a difference-scheme depends on the differentiability of the solution of the differential equation. In parabolic initial-value problems this is determined by the initial function. We examine the changing of the rate of convergence in dependence on the initial function.

Description / Table of Contents: Zusammenfassung Es wird das Verhalten eines bereitstehenden übermäßig komplexen Systems mit zwei Arten von Komponenten unter unvollständiger Umschaltvorrichtung ausgewertet.Laplace-Transformationen von wechselnden und festen Zustandswahrscheinlichkeiten werden berechnet. Ein spezieller Fall wird behandelt und diskutiert.

Description / Table of Contents: Summary The classical results on state reduction for complete deterministic automata (see [2]) can be proved for incomplete deterministic automata, too. This is especially due to the fact that, in spite of a widespread opinion (see e. g. [2], p. 45), the notion of equivalence of states of incomplete automata can be defined in a similar way as in the complete case (this has also been remarked bySchmitt [7]), and that the notion of state homomorphism may likewise be generalized. The proof becomes very easy, since, in analogy to the normal one-point compactification of a partial algebra (see [6]), we associate to each incomplete automaton a unique complete automaton such that minimality is preserved.

Description / Table of Contents: Summary For error estimates and convergence proofs frequently the norm of the inverse of a differential operator is needed. In this paper the norm of the inverse of a second order operator is bounded from above by a finite difference method. At the same time a sufficient criterion for the existence of the inverse is given.

Description / Table of Contents: Zusammenfassung In den vonDawidenko undGawurin eingeführten Lösungsmethoden simuliert man die nichtlineare Gleichung mit einem Anfangswertproblem einer Differentialgleichung. In diesem Aufsatz wird ein verwandtes Einbettungsverfahren angeführt, wo eine Reihe von lokal konvergenten Iterationsprozessen die globale Konvergenz auch ohne Kenntnis über die erste Approximation herzustellen vermag.

Description / Table of Contents: Summary The theorems, known for systems of linear equations, on the convergence of “Successive overrelaxation methods (SOR)” and “Alternating direction methods (ADI)” are transferred to analogous methods for systems of nonlinear equations. In doing so, only so-called “local” convergence theorems can be proved, however, as it is the case with other iteration procedures for nonlinear problems. Furthermore, it is examined under what conditions there exist difference approximations for nonlinear elliptic differential equations, such as to the functional matrix of the resulting system of nonlinear equations being symmetric and positive definite. SOR for 0〈ω〈2 and ADI are then converging. Such approximations can be derived at least for more general semilinear equations if the differential equation is theEuler equation of a variational problem. Finally, an example is given.

Description / Table of Contents: Summary As in [1], [6] and [8] is shown, round-off errors in numerical computation can be controlled with the aid of the intrrval analysis. This paper deals with the structure and the characteristics of the spaces occurring in interval analysis and presents some applications. At first the algebraic structure of these spaces is abstractly described by the definition of the quasilinear space, a generalization of the linear space. Then metric structures in these spaces are treated. As for applications only metrics are apt, which have a certain compatibility with the algebraic structure, such properties are introduced and examined. For the interval arithmetic with matrices and vectors metrics are developped, which are compatible with the algebraic structure and so are apt to estimate with. With these results for certain equations existence and uniqueness of the solution is proved as well as some iteration methods of interval analysis for the evaluation of the solution are examined and tests of convergence deduced. Finally it is shown how these iteration methods are to be carried out on a computer.

Description / Table of Contents: Zusammenfassung Numerische Lösungen von Randwertproblemen elliptischer Gleichungen mit diskontinuierlichen Koeffizienten sind von besonderem Interesse. In jenem Fall, wo die „Sprungfläche” (d. h. die Fläche der Sprungstelle der Koeffizienten) genügend glatt ist, ist auch die Lösung normalerweise glatt (außer auf der „Sprungfläche” selbst). Es bereitet einige Schwierigkeiten, einen hohen Grad von Genauigkeit zu erzielen, speziell, wenn die „Sprungstelle” nicht mit den Elementen zusammenfällt (in der Methode der finiten Elemente). In diesem Fall liegt die Norm des Fehlers in dem RaumW1/2 in der Größenordnung vonh 1/2 (siehe z. B. [1]) und im eindimensionalen Fall kann man leicht erkennen, daß die Genauigkeit nicht verbessert werden kann. In dieser Arbeit wird ein Weg (ähnlich [2]) gezeigt, welcher diese Schwierigkeit vermeidet. Der vorgeschlagene Weg wird an einem Modellfall erläutert — dasDirichlet-Problem mit einer Sprungfläche für dieLaplace-Gleichung; dadurch werden rein technische Schwierigkeiten vermieden. Die Randfläche und die „Sprungfläche” werden glatt genug angenommen. Eine hinreichende Bedingung für die Glattheit kann angegeben werden.

Description / Table of Contents: Summary The solution of the nonlinear boundary value problem $$y''(t) = - f{\text{ }}(t,{\text{ }}y{\text{ }}(t),{\text{ }}y'{\text{ }}(t)),{\text{ }}y{\text{ }}(0) = y{\text{ }}(1) = 0$$ under suitable conditions onf(t, u, v) is constructed by a variant ofPicards iteration method. The convergence of the iteration sequence follows by considering a second iteration process, of which the convergence is shown by the theory of strictly monotonic operators onHilbert spaces.

Description / Table of Contents: Summary The processing speed of three digital computers is measured by GAMM-mix for programs in machine code and in the programming Language ALGOL 60. By this you also find out the increase of the computing time for ALGOL separately for each computer. The GAMM-mix uses short test programs. But you get a different result of each computer's efficiency, if you use a Long program. Therefore the computing time needed for Long programs was also compared.

Description / Table of Contents: Summary 1. Growth and development of algae from spores has been observed in the laboratory (Menai Bridge) and under field conditions at Ravenspoint (West coast of Anglesey). Attempts were made to culture all main components of the sub-littoral flora. Spore material was obtained from spores allowed to settle onto plastic slides in the laboratory sea water system and from spores settled on slides stationed in the field. 2. Attention was given to the summer annual species and, in particular, to those members of the Nemalionales (Rhodophyceae) which have incompletely known life histories. In these plants, the tetrasporic phase during which reduction division normally takes place, has so far been undetected in the field. The plants are represented by the cystocarpic phase of the life cycle only. 3. The fate of the carpospores of these species were of particular interest. The spores of the annual species were cultivated under a number of regimes of irradiation and temperature. Sporelings from laboratory culture were transferred to the field in November, 2 months after settlement. Both in laboratory and field, the form of development of the cultures were similar until May of the following year. Then the field cultures developed structures which may represent the tetrasporangia of the alternate phase. These structures failed to develop in the laboratory cultures after 3 years. 4. The results of these experiments illustrate that care must be taken in interpreting results of laboratory cultures of algae, in particular in regard to their life histories.

Description / Table of Contents: Summary 1. Assay experiments with unialgal cultures have been carried out in connection with an investigation of the Oslofjord 1962 to 1965. The test algae included the following species:Selenastrum capricornutum Printz,Chlorella ovalis Butcher,Skeletonema costatum (Grev.)Cl. andPhaeodactylum tricornutum Bohlin. 2. In the Oslofjord three different types of water are mixed: sea water from the open sea, fresh water from the tributaries, and polluted discharges. The algal growth assays have given information on the amounts and availability of plant nutrients in the water. The quality of the water for algal growth was determined. 3. The results indicated that the water of the inner part of the fjord was in a condition where a significant increase in sewage load gave a relatively small increase in algal growth. Conversely, it was found that for water samples from the outer Oslofjord, a small addition of sewage would give relatively high increase in growth. 4. Enrichment experiments with essential nutrients showed that the supply of compounds of nitrogen, phosphorus and iron was important for the resulting yield of algae. It was not possible to ascribe the main fertilizing effect to any single one of the components.

Description / Table of Contents: Zusammenfassung 1. Kulturverfahren zur Ermittlung der Salz- und Überflutungsverträglichkeit vonPuccinellia-Arten wurden auf Grund von etwa 450 Standortanalysen an Standorten vonP. maritima und eingehenden Vorversuchen ausgearbeitet. Hiernach ergeben sich fürP. maritima (Sort. Nr. 57) folgende Optimalbedingungen: (a) Temperatur: 17–23° C; (b) Lichtintensität: 10 000 Lux und mehr; (c) Tageslänge: Langtag von 16 Std. und mehr (Ausläuferentwicklung); (d) überflutung: 2mal täglich (alle 12 Std.) bis 1 cm über Bodenoberfläche; (e) Boden: Hirschauer-Quarzsand + 3 % Flora-Torf; (f) Nährlösung: 1,1 ‰ Grundnährlösung bis 5 ‰ künstliches Meerwasser. 2. Die Kulturverfahren basieren auf einer stufenweisen Kultur mit künstlichem Meerwasser von 0–60 ‰ bzw. auf einer stufenweisen Überflutungszeit von 0 bis 2,5 Std. im Abstand von 12 Std. und werden in einem Gewächshaus durchgeführt. 3. Die Methoden (bzw. Fehlerquellen und Übertragbarkeit auf die natürlichen Standortverhältnisse) werden diskutiert.

Description / Table of Contents: Summary 1. The planktonic North Sea algaPhaeocystis poucheti was cultivated in the laboratory. The influence of light, temperature and nutrients was investigated by employing several culture methods. The influence of industrial and domestic waste water was also studied. 2. TheP. poucheti forms both colonies and free, motile or nonmotile, single cells. The single cells have the tendency to attach themselves to solid surfaces and, from there, to release continuously new free single cells and small colonies into the ambient water. 3. The multiplication rates of the two planktonic stages and of the sessile stage ofP. poucheti have been determined and their quantitative inter-relations studied under various culture conditions. 4.P. poucheti was cultivated in “Erdschreiberlösung”, “Schreiberlösung” and pure sea water. The cultures were set up (a) in petri dishes, (b) in 1 or 10 l bottles without renewal of nutrients as mass cultures, and (c) in turbidostats, limiting cell density to a constant optimal level by the daily removal of old, and the addition of new, culture medium. 5. Under conditions which ensure a permanent supply of fresh culture medium and a low cell density, the colony stage predominates over the single cell stage. However, if maximum cell density is reached in a nutrient enriched culture medium, the single cell stage is favored, whilst the colony stage very quickly decreases in number. In pure sea water the colony stage predominates all the time. 6. Cultivation in “Schreiberlösung” results in maximum cell densities of about 400,000 cells/ml in the colony stage, and of about 2,000,000 cells/ml in the single cell stage. Cultivation in pure sea water leads to maximum cell densities of about 100,000 cells/ml in the colony stage and of about 18,000 cells/ml in the single cell stage. Under optimum conditions the rate of multiplication in the planktonic stages reaches two cell divisions per day. 7. Industrial waste water (consisting primarily of H2SO4 and FeSO4) from a titanium dioxide factory favors the growth of the colony stage ofP. poucheti in a dilution of 1 part waste water : 100,000 parts “Schreiberlösung”. A dilution of 1 : 4,000 significantly reduces the multiplication rate of colonies. A dilution of 1 : 2,250 is lethal. 8. After addition of unfiltered domestic sewage (from the sewage outflow on Helgoland) in concentrations of 1–5 parts sewage water to 1,000 parts sea water a vigorous development of the colony stage is followed very quickly by damage to the colonies. The single cell stage, however, shows (in these sewage water concentrations) slightly increased multiplication rates all the time. In concentrations up to 10 parts sewage water to 1,000 parts sea water the toxic effect predominates in both stages.

Description / Table of Contents: Summary 1. The quantitative distribution und the size/weight structure of population of the edible molluscsMizuhopecten yessoensis (Jay) andSpisula sachalinensis (Schrenk) have been studied on the shores of Southern Primorje (Sea of Japan) during different seasons of the year. 2. By counting the size-age groups (which correspond to certain generations) constituting a given population, the age of individuals of different size and the maximum individual life-time were determined. 3. The characteristics of growth (weight increase) and calculation of fluctuations in abundance of generations of different age, have enabled the authors to estimate the nett population growth production (expressed as weight increase of all specimens of a population per year at the time of control). The average annual population growth production was determined by averaging the values obtained for each of the four seasons. 4. The living matter accumulated over a year and retained by the individuals of the population, as well as the matter contained in shells, was calculated by adding up the weight of the young present at the time of control (including specimens less than 1 year old) and the annual weight increase in the older specimens available. The value obtained is designated as supporting production; it constitutes the minimum rate of production of living matter required for maintaining the size of a population at a stationary level. The average annual supporting production is the sum of the productive process for a year. It was determined by dividing the values obtained for each of the seasons by 4 (i. e. by the number of seasons). 5. The average annual population growth production ofMizuhopecten yessoensis in the areas studied, is 131 g/m2, and the supporting production 32 g/m2; theP/B indices are 1 and 0.25, respectively. The greatest biomasses and maximum production rates occur in summer; they decrease considerably in winter and begin to increase again in the spring. 6. The average annual population growth production ofSpisula sachalinensis is 451 g/m2, and the supporting production 329 g/m2; theP/B indices are 0.55 and 0.39, respectively. Maximum biomass and production rates are observed at the beginning of winter because of winter aggregation of specimens in the study area; the rate of turnover of organic matter is small during the cold period. TheP/B indices reach their highest value in autumn. 7. The hydrological conditions and the biotic background at the shores of the Southern Primorje are favourable for spawning and for the planktonic stages of both species. 8. InMizuhopecten yessoensis the larvae settle on submerged plants. The factors which badly limit the abundance of this species are the shortage of substratum for settling and the predation on young settled individuals especially by sea stars. Artificial increase in abundance of the species may be accomplished by: (a) offering sufficient settling area; this can be done by placing suitable collectors in the habitat; (b) protecting the settled young from predators. 9. Abundance ofSpisula sachalinensis is most appreciably limited by the effect of storm waves, which cast numerous young, weak individuals ashore into the intertidal zone, where they perish owing to unfavourable conditions. Collection of young individuals cast ashore and their transfer into protected farm areas favourable for growth is recommended for artificial increase in the abundance of this species.

Description / Table of Contents: Summary 1. Veligers ofCrepidula fornicata (L.) andNassarius reticulatus (L.) were fed on the algaeCricosphaera ap.carterae, Dunaliella primolecta andExuviaella baltica (each at a concentration of 20 × 103 cells/ml) in suspension in columns of seawater (height 115 cm), and their movements observed over a 5 to 8 h period. 2.Nassarius reticulatus larvae were also fed on three artificial foods (cornflour, drinking chocolate and Liquifry — consisting mainly of pulverised diatoms) which settle to form a layer on a substratum and their growth was measured over a 12–14 day period. 3. The time taken from the first mouthful to the first defecation was recorded for larvae feeding on all six foods. 4. There are two patterns of swimming activity associated with feeding on algae in suspension dependent upon the food value of the alga to the particular species of veliger. 5. With a good food(Cricosphaera ap.carterae andDunaliella primolecta forNassarius reticulatus, Exuviaella baltica forCrepidula fornicata) all larvae congregate at the surface to feed, dropping intermittently 26 to 34 cm while digestion continues. The first defecation occurs about 30 min after feeding begins. 6. With a poor food(Exuviaella baltica forNassarius reticulatus) and without food, larvae are distributed more evenly throughout the water column and make random swimming movements. 7. When no food is present in the column two rising rates are evident 20–30 sec/cm and 7–8 sec/cm, and one sinking rate 20–34 sec/cm. This also holds in the presence of bad and good foods except inCricosphaera ap.carterae in which larvae rose more slowly (40 sec/cm). 8. The treatment of the six foods in the gut differs: when the stomach is full, feeding more or less ceases in case of algal foods and faeces are formed after 30 min; feeding is more continuous with artifical foods only some particles being retained for digestion and faeces are produced after 10–15 min. 9. Some growth ofNassarius reticulatus occurs in artificial foods, although it is less than inCricosphaera ap.carterae, and ceases after 8–10 days. Growth over the first seven days is most vigorous in cornflour, good in Liquifry but poor in drinking chocolate owing to bacterial contamination. Growth resumed when larvae fed on Liquifry were givenCricosphaera ap.carterae indicating that they remained healthy. 10. The concentration of cornflour and Liquifry is a critical factor. At 2 × 103 particles/ml growth was poor, probably as a result of starvation, and a concentration of 20 × 103 particles/ml or higher is recommended. 11. The food value of an artificial food affects growth. Cornflour and drinking chocolate have a very high carbohydrate content giving an unbalanced diet. Liquifry has a more balanced food content but it contains large amounts of indigestible material which must reduce the food value. 12. Artifical foods can be used to maintain cultures of larvae over a short period, but not for long term growth as they lack essential micronutrients present in natural algal foods.

Description / Table of Contents: Summary 1. Larvae ofCrepidula fornicata (L.) andNassarius reticulatus (L.) were used for experiments. The conditions under which they thrived proved successful for veligers of other species. 2. They were kept in glass-filtered sea water (pore size 3.0µ) in acid-clean glass containers, provided with algal foods and handled carefully by means of a pipette. Trapping larvae in a coarse filter as a means of transferring them from one vessel to another was injurious. 3. Shell length was used to estimate growth. 4. The growth of 20 veligers in 30 ml sea water (depth 8 cm) was compared with that of 333 veligers in 500 ml (depth 9 cm). Growth in the larger volume was better, but in all cases the differences were not significant at the 10% level. 5. Growth rate is influenced by light intensity. For comparing the value of different foods experiments were carried out under a constant intensity of 155 lux at the water surface. In the dark, mortality of algal cells stimulates growth of bacteria. 6. The water temperature was maintained at 12° C. Low temperatures, even 8° C, reduce the activity of veligers ofCrepidula fornicata andNassarius reticulatus; high temperatures favour bacterial growth. 7. The growth of recently hatched veligers feeding on one of 10 species of unicellular algae and on some mixtures of these was recorded for 2(C. fornicata) or 3(N. reticulatus) breeding seasons. Food was given at different concentrations (2 × 103, 20 × 103, 40 × 103 cells/ml) which were calculated from haemocytometer counts of the stock cultures, though this gives only an approximate value. Experiments lasted up to 4.5 weeks and a few for a longer period. 8.Cricosphaera ap.carterae andExuviaella baltica were the best foods forCrepidula fornicata, especially at higher concentrations, and larvae were ready to metamorphose in 40 days or less.C. ap.carterae andDunaliella primolecta were good forNassarius reticulatus, especially the former, andE. baltica consistently poorer. 9.Monochrysis lutheri andPyramimonas grossii were moderately good foods, but with these none of the larvae metamorphosed. When fed toCrepidula fornicata at high concentrations (80 × 103, 120 × 103 cells/ml) growth of the former approached that withCricosphaera ap.carterae whilst with the latter growth decreased with increased concentration. The food value ofPhaeodactylum tricornutum is lower; the large frustules irritate the gut and act as a purgative. 10.Chlamydomonas parkeae, Brachiomonas submarina, Exuviaella pusilla andOlisthodiscus sp. are poor foods; the last two are toxic. 11. When the food was 2 species of alga mixed in equal proportions the good value ofCricosphaera ap.carterae was still evident. Examination of the stomach contents showed that the larvae were not feeding selectively on this alga. When the second alga was one with smaller cells(Monochrysis lutheri orPyramimonas grossii) these were ingested in greater numbers in accordance with the ease with which the velar cilia manipulated them. 12. Algal cells are subjected to mechanical treatment in the stomach; their walls may be shattered but no fragment has been seen in the cells of the digestive gland. The resistance of cells with complete cellulose walls suggests the absence of a cellulase. 13. With some algal foods (species ofMonochrysis, Pyramimonas, Phaeodactylum) the walls produce a high proportion of faecal waste which, in less vigorous larvae, may clog the exhalant passage of the mantle cavity. 14. Plant pigments are egested by the veliger. They are intimately linked with food, taken into ingesting cells of the digestive gland and later excreted. They thus delay the cycle of events in the gland. 15. Differences in food value of the various algae may be due to differences in micronutrients and vitamins essential to growth. The fact that one species of alga may produce good growth in one species of veliger and not another must reflect either differences in requirements or in assimilation of the food. 16. Prosobranch veligers are found in numbers well below the compensation depth as well as in other areas where the density of algal cells is low. It is suggested that organic detritus in the sea is an important item of food.

Description / Table of Contents: Summary 1. Using 6 phytoplankton species and/or the copepodEuterpina acutifrons or larvae of the sea urchinArbacia lixula the potential inhibitory effects of chemicals released from some 70 different materials (mainly plastics) have been tested. In addition, the effects of 6 detergents have been examined. 2. Several materials, such as natural rubbers and polyvinyl chlorides, are highly toxic and should never be used when experimenting with living marine organisms. 3. Teflon (Algoflon), Perspex, Polyethylene, Tygon, Polypropylene, Polycarbonates (Makrolon) and Polyester (Gabraster) have been shown to be non-toxic and are, therefore, suitable for use in cultivation of marine organisms. Some materials had slightly negative effects on the organisms tested and should, therefore, be used only if no alternatives are available. 4. Some suggestions are advanced on how to construct non-toxic samplers and laboratory equipment used for experiments with marine organisms.

Description / Table of Contents: Summary 1. Larvae of decapod crustaceans, especially crabs, change their capacity to osmoregulate from day to day and between moult stages. 2. These changes are related to alterations in internal osmoconcentration so that inward flow of water increases body turgor to assist in the moulting process. 3. It is useful, therefore, and often essential, to be aware of these physiological events during the course of culture.

Description / Table of Contents: Summary 1. Experiments in the natural habitat and under laboratory conditions have been conducted to analyse the factors responsible for the orientation of the fans of the colonial hydroidAglaophenia pluma. These experiments indicate that the prevailing direction of water movement significantly affects fan positioning. 2. Field experiments reveal thatAglaophenia pluma growing onCystoseira sp. orientates the dorsal side of its fans towards the base of this algae. After detaching and turning of substrate piecesA. pluma colonies lose their fans and re-orientate the regenerating fans prevailing to water current. 3. Laboratory experiments in running water onAglaophenia pluma var.teissieri show, as in the field, dorsal fan orientation perpendicular to the water current; however, rate of up growth is much slower than in the field. 4. Simulation of oscillating water movement, characteristic of the natural habitats of the species investigated, was possible via a special, newly designed pump system. The new system is described. 5. TheAglaophenia pluma var.teissieri fans were fixed with their rocky substrate on a turntable and exposed to the oscillating water movement in a current canal. After the fans have been cast off, the oscillating water movement induces a much higher rate of growth than the running water only. The orientation of the fans was strictly perpendicular to the current. 6. On the margins of the substrate exposed to the current, the fans were orientated with their dorsal surface toward the margin; in the centre of the rock fragments the fans are also strictly orientated perpendicular to the current with their dorsal sides showing in either direction. 7. A close study of the flow of current at the edges of the substrate showed that the whirls may diminish or even reverse the current coming from the substrate side. The orientation of the fans with their dorsal side outwards shows that they orientate themselves to the strongest current. 8. The orientation of a developing fan is basically determined by the first polyp. However, by slow, step by step turning of the upgrowing fan, a helically twisted fan could be obtained, indicating that secondary directioning is possible during growth. Twisted fans can also be found occasionally in the field; presumably they grew up under alternating current directions.Aglaophenia pluma var.teissieri exposed to permanent rotation give rise to regenerating fans which are orientated in the same way as the previous set of fans (preceding cast off).

Description / Table of Contents: Zusammenfassung 1. In einer aus Zoosporen vonDerbesia marina entstandenen Gametophytengeneration trat eine einzelne Pflanze vom Habitus des Sporophyten auf. Ihre Fäden entsprangen einer zentralen kugeligen Anschwellung. 2. Diese Mutante erzeugt aus geschlechtlich neutralen Schwärmern immer wieder gleichartige Generationen. 3. Die Mutante ist haploid (vgl.Neumann 1969). 4. Die Befunde bestätigenFeldmanns (1952) Hypothese der Entstehung neuer Arten durch Trennung und selbständige Entwicklung von Gliedern eines Lebenszyklus.

Description / Table of Contents: Zusammenfassung 1. Fakultative Karyogamie konnte bei keiner der untersuchtenAcrosiphonia-Arten nachgewiesen werden. Alle Arten mit geschlechtlicher Fortpflanzung können sich zusätzlich durch zweigeißelige Schwärmer vermehren. 2.Acrosiphonia spinescens hat heteromorphen Generationswechsel; der Sporophyt ist Codiolum-artig, der monözische Gametophyt fädig. Unverschmolzene zweigeißelige Schwärmer entwickeln sich ebenfalls zum Codiolum-Stadium, in seltenen Fällen auch direkt zu fädigen Pflanzen. 3. Dieser wie auch Punkt 5 sind keine Ergebnisse der vorliegenden Studie, ihr Inhalt ist aber für das Verständnis der Zusammenhänge notwendig. Die isländischeA. grandis hat keinen Generationswechsel, jedoch vereinigt ihr Thallus heteromorphe Bauelemente. Das aus der Zygote zunächst entstehende typischeCodiolum wächst im 16-Kern-Stadium — vermutlich nach vollzogener Reduktionsteilung — unmittelbar zur fädigenAcrosiphonia aus. Die Entwicklung zweigeißeliger Schwärmer zeigt keine morphologischen Unterschiede (Kornmann 1970). 4. AuchAcrosiphonia arcta hat keinen Generationswechsel; die zygotische Phase beschränkt sich auf die erste Zelle ihres fädigen Thallus. Nach wahrscheinlich meiotischer Teilung vierkernig geworden, wächst die Zygote zum fädigen Thallus weiter. Keimlinge aus zweigeißeligen Schwärmern werden nach der ersten Kernteilung zweizellig, ihre weitere Entwicklung gleicht der aus Zygoten. 5.Acrosiphonia sonderi pflanzt sich ausschließlich durch ungeschlechtliche zweigeißelige Zoosporen in gleicher Weise fort, wie dies beiA. arcta undA. spinescens zusätzlich der Fall ist (Kornmann 1962b). 6. DieAcrosiphonia-Arten mit geschlechtlicher Fortpflanzung zeigen eine stufenweise Reduktion der Diplophase von einer absoluten über eine zeitlich begrenzte Selbständigkeit bis zur völligen Einbeziehung in einen einheitlichen Organismus. Die Fähigkeit unverschmolzener Schwärmer, sich direkt zu entwickeln, verbindet diese Arten mit denen ohne geschlechtliche Vermehrung. 7. Die Kenntnis der Lebenszyklen derAcrosiphonia-Arten bildet die Grundlage für eine systematische Gliederung der Gattung, deren Arten in vielen Fällen kennzeichnender morphologischer Unterschiede ermangeln.

Description / Table of Contents: Zusammenfassung 1.Belone belone L. wurde von der künstlichen Befruchtung an bis zu einer Totallänge von annähernd 10 cm unter kontrollierten Laborbedingungen aufgezogen. 2. Dottersacklarven zeigten unter verschiedenen Lichtbedingungen „Igelstellungen“, die in Anlehnung anMagnus (1967) als Fluchtintensionsbewegung interpretiert werden. 3. Die Beutefanghandlungen erreichen schon zur Zeit der ersten Nahrungsaufnahme eine außerordentlich hohe Anfangstreffsicherheit. 4. Larven und Jungfische nehmen Kunstfutter sehr gut von der Oberfläche her auf. 5. Bei Totallängen zwischen 16 und 25 mm neigen die Jungfische besonders stark zum Kannibalismus. 6. Die mit 12,5 mm Totallänge schlüpfenden Larven wuchsen bei 22° C in den ersten 14 Tagen im Mittel bis auf 29 mm, innerhalb von 35 Tagen auf 45 mm und in 80 Tagen auf etwa 93 mm heran. Bei einer Aufzuchttemperatur von 26° C wurden 90 mm Totallänge bereits nach 60 Tagen erreicht. 7. Die Überlebensrate betrug während der Dottersackphase und zur Zeit der ersten Nahrungsaufnahme annähernd 100%. Die durch Kannibalismus verursachte Sterblichkeit erreichte mehr als 60%. Erhebliche Verluste wurden dabei sekundär durch Pilzinfektionen und parasitäre Ciliaten verursacht.

Description / Table of Contents: Zusammenfassung 1. Im Litoral der karibischen Küste Kolumbiens wurden 145 Prosobranchier-Arten nachgewiesen, die 79 Gattungen und 44 Familien zugehören. Die Arten werden beschrieben und abgebildet. 2. Die Aufsammlungen wurden vor allem an den Küstenstreifen von Santa Marta, Cartagena und der Halbinsel Guajira gemacht. Dabei wurden die Biotope Felslitoral, Korallenriff, Sandstrand und Brackwasserlagune erfaßt.

Description / Table of Contents: Summary 1. A new growth medium for Thiorhodaceae and Chlorobacteriaceae was adopted for the isolation of members of these bacterial families from marine habitats. 2. 47 strains comprising 13 species were enriched and isolated in pure cultures. 3. The strains were classified by physiological and morphological characteristics. 4. Many of the strains represent species in pure culture for the first time.

Description / Table of Contents: Summary 1. Spanish industrial firms and scientific institutions are interested in cultivating the oyster,Ostrea edulis L., for commercial and scientific purposes. Even though bays in Galicia (Northwest Spain) appear to be well suited for oyster cultivation, success has been rather limited thus far. 2. The local natural beds ofOstrea edulis are largely exhausted for several years. The Galician oyster cultivation is, therefore, at present limited to the import of middle sized oysters (mainly from Brittany) and their fattening during the favourable season, i.e. March to November, in suitable natural habitats. 3. Sufficient rates of reproduction of the fattened oysters are difficult to attain because (a) the oysters are attached to vertically arranged ropes and hence not stimulated to spawn simultaneously (large vertical gradient at critical temperature which stimulates spawning), (b) settling oyster larvae are not sufficiently attracted due to the absence of suitable natural and artificial substrates. 4. Experiments are presently being carried out employing traditional larvae collectors (tiles) and laboratory-raised oyster spat fed on phytoplankton cultures and amylaceous products. 5. Low salinities in winter, lack of oxygen in summer and adverse qualities of the natural substratum increase the mortality. Under present circumstances, fattening of middle-sized oysters appears to be still the most satisfactory method with regard to commercial view points.

Description / Table of Contents: Summary 1. Techniques are discussed for obtaining bivalve embryos and larvae throughout the year by inducing gonad development in adults during winter and spring and retarding spawning until late fall and early winter. 2. Development of routine methods for rearing larvae is described and data are presented on the food, temperature, salinity, and pH requirements and on the effect of different combinations of these factors on survival and growth of larvae of several species of bivalves. 3. Some general conclusions are given on the effects of suspended materials, various pollutants, and toxicants on embryos and larvae. 4. Progress in the study of genetics of bivalves is reported.

Description / Table of Contents: Summary 1. Group-O plaice,Pleuronectes plattessa L., were grown on partially defined diets containing different levels of protein. 2. The growth rate appeared to increase linearly as the protein content of the diet was increased up to the highest level used (70% of the dry diet). 3. A conversion rate of 1.6 was obtained with diets containing 50% or more of protein. 4. The protein efficiency ratio on all diets was near unity. The maximum value obtained being 1.16 with the 50% protein diet.

Description / Table of Contents: Summary 1. 52 Pied Flycatchers which were hand-raised as „Group-Hausers“ with no opportunity to encounter predators were exposed individually to one of several enemy and control objects at an age of 5 to 7 1/2 weeks. 2. The juveniles showed avoidance of about equal strength to a living Little Owl and a living female Shama but of lesser strength to mounted specimens of a Pigmy Owl and a male Redbacked Shrike; the avoidance to the living birds, however, was, without exception, weaker than that of wild adults to mounted owls and shrikes. 3. The living Little Owl was mobbed at by the juveniles stronger than all other bird objects tested; some of the subjects responded as strongly as wild adults in the same situation. From this result it appears thatindividual experience with predators is unnecessary for the development of the owl mobbing response. The failure of the Shama to evoke mobbing might suggest that not every living and novel bird is mobbed at. 4. Why wild adults in contrast to the juveniles tested, respond about equally strongly to mounted and living owls and show a stronger avoidance of all comparable bird objects, remains unknown. 5. The auditory perception of strong conspecific mobbing played back by tape does not seem to alter the response to the simultaneous presentation of the living owl. 6. The experience with the living owl does not seem to influence the response to the mounted Pigmy Owl afterwards. 7. The avoidance of novel birds is motivated by at least two tendencies, namely exploring and fleeing. Mobbing includes avoidance and will be released by more specific sign stimuli; its motivation is still more complex.

Description / Table of Contents: Summary 1. Two and three year old specimens ofLaminaria hyperborea were transplanted to sub-tidal growth stations at 2 and 6 m water depth, respectively. 2. Maximum growth rate occurred in early May in specimens growing at 2 m depth, and in early June at 2 m depth. 3. Frond area size, attained by the specimens growing at 6 m depth in July, was at least 75 % of frond area size attained at 2 m depth. Stipe length of plants at 6 m depth, as recorded in July, was only about 1/3 of the stipe length attained at 2 m depth. 4. Growth rates of new phylloids ofLaminaria hyperborea specimens kept in darkness from February until May are considerably reduced, if the old frond is amputated.

Description / Table of Contents: Summary 1.Cyclotella nana Hustedt (clone 13-1) was found to grow in sea water at salinities ranging from about 15 to 50 parts per thousand. 2. Investigation of the osmotic requirement in the region of poor growth at the lower salinities, revealed that this alga gives an osmotic response at a relatively high osmotic pressure. 3. The osmotic and ionic requirements can be clearly distinguished and it was shown that this oceanic diatom can survive at sea water dilutions as low as 1/6 of full strength of water from the Sargasso Sea when the osmotic pressure is adjusted with sucrose. 4. The requirements of the four main cations (Na, K, Ca, Mg) are discussed.

Description / Table of Contents: Summary 1. Isolated cells from disintegrated monosiphonous branches of the rhodophyceanDasya pedicellata are able to grow into fully developed plants and to perform vegetative propagation. 2. Cultures of germlings from those cells, as well as carpospores and tetraspores, attain maximum growth rates in salinities lower than that of normal sea water. 3. In spite of its sublittoral occurrence,Dasya pedicellata tolerates a wide range of salinities.

Description / Table of Contents: Summary 1. The growth potential of November surface waters collected at 3 stations in Phosphorescent Bay, Puerto Rico, for the diatomsBacteriastrum hyalinum, Cyclotella nana (13–1),Skeletonema costatum, andThalassiosira rotula was determined after enrichment in various ways. 2. Enrichment experiments were also conducted at 14 stations in the Caribbean Sea usingThalassiosira rotula as the bioassay diatom, and at 4 stations usingBacteriastrum hyalinum. 3. Marked differences in response occurred, based on growth for 5 days at 20° C and 700 ft-c of continuous, artificial illumination. All surface waters were toxic toBacteriastrum hyalinum; Thalassiosira rotula grew well only in the innermost waters of Phosphorescent Bay, and at 3 of the 14 Caribbean stations.Skeletonema costatum grew only at 2 of the 3 Phosporescent Bay stations (the converse of theThalassiosira rotula response), andCyclotella nana (13–1) at all stations. 4. Growth was either stimulated, inhibited or unaffected by certain nutrients; a combination of natural nutrient limitation and inhibition influenced growth. 5. Transect gradients occurred in the relative influence of various nutrients on growth, such as the omission of silicate from the complete enrichment which led to a progressive, offshore improvement in growth ofSkeletonema costatum, whereas phosphate omission limited growth ofBacteriastrum hyalinum. 6. The occurrence of marked short scale differences in water quality (“chemical patchiness”) is suggested by the station to station variations in effect of a given nutrient or nutrient combination on the growth of a given species and growth differences between species. These effects were not predictable from the hydrographic observations. Individual species responses to a specific nutrient enrichment were likewise unpredictable from a given species' known bioassay response. 7. The relevance of the demonstrated occurrence of “chemical patchiness” to the examination of the general problems of succession and distribution of species is briefly discussed.

Description / Table of Contents: Summary 1. Five species of heterotrophic Protozoa are presently under investigation in this laboratory. They are: the tintinnid,Tintinnopsis beroidea, 2 species of dinoflagellate,Cryptothecodinium cohnii andNoctiluca scintillans, and the choanoflagellatesDiaphanoeca grandis andAcanthoecopsis sp. 2. Their nutritional status and some potential applications are discussed, along with some observations on other tintinnids previously cultured.

Description / Table of Contents: Summary 1. The polychaeteOphryotrocha labronica La Greca &Bacci is proposed as test animal for marine pollution research. It also provides excellent material for classroom studies. 2. The size ofO. labronica seldom exceeds 4.5 mm; it is herbivorous and can be cultured in crowded populations in limited amounts of sea water. As it is possible to work at the population level, experimental results are easily available for statistical analysis. 3. Growth rate, ability to reproduce and the duration of different stages of the life cycle form convenient parameters. In addition, useful observations can be made on locomotion, feeding and mortality. 4. All life cycle stages are available for experiments throughout the year. At 20° C, the whole life cycle is completed in less than 1 month. 5. The reproductive capacity is enormous. A female produces an average progeny of 120 and may repeat egg laying every second week for at least 3 months. The reproduction cycles of females can be synchronized yielding large populations of equal sized young larvae. 6. Cultivation methods are described, as well as experiments conducted under varying conditions of nutrition, temperature and salinity. 7. The effects of pollutants (ethylene glycol, sulphuric acid) on different life processes are considered.

Description / Table of Contents: Summary 1.Calanus helgolandicus was grown from egg to adult in agitated seawater cultures at 15° C in the laboratory. 2. The chain-forming diatomsChaetoceros curvisetus, Skeletonema costatum, Lauderia borealis and the dinoflagellateGymnodinium splendens were offered as food. The concentration of food, resembling phytoplankton concentrations found in the ocean off La Jolla, ranged from 28µg to 800µg carbon per liter. 3. Depending on food quality and food concentration, the time from hatching to adulthood lasts between 18 and 54 days. Mortality from hatching to adulthood ranges from 2.3% to 58.2%. The length of adult females is directly related to the amount of food offered; it ranges from 3.03 mm to 3.84 mm. 4. The sex ratio in different batches of laboratory grown copepods varies considerably. The largest percentage of males (about 25%) was obtained withLauderia borealis orGymnodinium splendens as food source. 5. The fecundity of females grown and fertilized under laboratory conditions averages 1991 eggs per female with a hatching percentage of 84%. These values are close to those obtained from spermatophore-carrying females from the ocean (2267 eggs per female; hatching percentage 77%).

Description / Table of Contents: Summary 1. Methods are reported for the cultivation of harpacticoid copepods in the laboratory and their utilization for genetic research. 2. Experimental evidence has been obtained that certain ecological parameters, such as salinity and temperature, act as powerful selective agents. This has been demonstrated by considering the effects of the physical environment on the visible polymorphism as well as on the concealed genetic variability. 3. The first results of a series of experiments show that biotic factors can play a selective role which is at least as much effective as that played by physical factors. 4. Another line of investigation followed consists in the study of reproductive isolation between geographic populations of the same species.

Description / Table of Contents: Zusammenfassung 1. Die Probleme der Kultur mariner niederer Phycomycetes sowie die Physiologie dieser Pilzgruppe stellt zum gegenwärtigen Zeitpunkt ein weitestgehend unbearbeitetes Teilgebiet mykologischer Forschung dar. 2. Einzelstudien sowie die mitgeteilten Untersuchungsergebnisse lassen bei einer wesentlichen Intensivierung dieses Forschungszweiges wichtige allgemein interessante Ergebnisse erwarten. 3. Diese beziehen sich auf Erkenntnisse zum Verständnis des Stoffumsatzes und des Stoffkreislaufes des Meeres und würden gegebenenfalls weitere, noch nicht in ihrer Tragweite überschaubare Grundlagen für die marine Ökologie liefern. Sie dürften auch für die Abschätzung anthropogener Einflüsse auf das Leben im Meere für die Zukunft entsprechende Bedeutung erlangen.

Description / Table of Contents: Summary 1. The present status of oyster farming in Japan is reviewed. 2. The biology of the oysterCrassostrea gigas, a main farming species in Japan, is briefly discussed, especially in regard to spawning. 3. The farming procedures are described with special reference to suitable farming conditions, spat collecting methods, techniques and facilities for fattening (growth), and seasonal activities. 4. The yield rate of Japanese hanging methods are discussed in comparison with methods and yields of other countries. 5. Some important future problems are discussed: the need to preserve growth fields against deterioration; the need to simplify the procedures to save labor; and the need to protect farming sites from pollutants.

Description / Table of Contents: Summary 1. A method has been developed for rearing large numbers of the larvae of the barnacleElminius modestus. At 20° C, frequent changing of the sea water medium treated with antibiotic allows 25 to 50% of the original larval population to settle and metamorphose to the adult stage. 2. The diatomSkeletonema costatum has been used as food source in a concentration of 5 × 105 cells/ml sea water. 3. The rearing temperature affects not only the rate of development but also the size of the larvae. 4. Constant illumination appears to provide optimum conditions for uniform rearing of larvae in large numbers. 5. Cyprids appear after approximately 7 days and settlement occurs about 3 days later. 6. In the laboratory, young adult barnacles will grow faster in flowing sea water than under static sea water conditions, even though supplementary food is added to the latter.

Description / Table of Contents: Summary 1. During an investigation on the numerical variations in vertebral counts ofPomatoschistus minutus (33 vertebrae) undP. lozanoi (32 vertebrae), larvae of these closely related gobies were reared from eggs to young fish. 2. From 1963 to 1965, rearing was not very successful; it yielded 34 to 220 young fish with estimated survival rates of the larvae between 2 and 10 %. Rearing methods were improved and yielded 66 % survival in 1966; 1,585 young fish were reared from 2,400 larvae; in some experimental groups survival was approximately 90 %. 3. The seawater of the closed rearing system used in 1966 was treated with ozone; antibiotics were added in concentrations of 20 I.U. penicillin G + 10µg streptomycin per ml seawater. 4. The larvae were fed natural zooplankton, washed and sieved through plankton gauze of different mesh sizes. 5. A description is given of the rearing method used in 1966 and the development ofPomatoschistus lozanoi larvae. 6. Growth rates of the larvae were in the order of 21 to 39 mm increase in length per 100 days at 14° to 16° C. The larvae changed to bottom life 31 days after hatching at a total length of approximately 12 mm. 7. Eggs ofPomatoschistus lozanoi (32 vertebrae), incubated at temperatures of 10° to 20° C until attainment of the “eyed egg” stage, yielded offspring (hatched and raised at 16° C) with a mean vertebral number of 31.90 (n=1,585) and a variation in mean vertebral number for the various experimental groups from 31.73 (n=206) to 32.13 (n=122 vertebrae). Crossings of fishes with 32 vertebrae and 33 vertebrae yielded offspring with a mean vertebrae number of 32.44 (n=34), 32.55 (n=107) and 32.65 (n=118), respectively.

Description / Table of Contents: Summary 1. Various designs and techniques of closed system rearing of fish larvae are being developed using specific species chosen on the basis of their reproductive habits, ecological preference, and potential as environmental indicators. 2. The influence of the parameters of temperature, salinity, food, light, circulation, and the presence of autotropic organisms are tested using as criteria for the success of hatch and development. 3. To date, the results have produced several techniques which increase the percentage of success in raising fry and juvenile fishes.

Description / Table of Contents: Zusammenfassung 1. Im Rahmen eines Übersichtsreferates werden einige allgemeine Prinzipien der Laboratoriumszucht mariner Wirbelloser abgehandelt. 2. Als Voraussetzungen einer kontinuierlichen Zucht werden u. a. herausgestellt: die Auswahl geeigneter Arten und Zuchtgefäße, die Berücksichtigung der für das Gedeihen entscheidenden Umweltfaktoren und Maßnahmen zur Aufrechterhaltung des biologischen Gleichgewichtes in einer Kultur. 3. Die Bedeutung der Zucht wirbelloser Meerestiere für die experimentelle Zoologie wird anhand einiger Beispiele wissenschaftlicher Untersuchungen illustriert.

Description / Table of Contents: Zusammenfassung 1. Vor der Küste von Madagaskar wurde in 14 m Tiefe eine Massenansammlung des SchlangensternesAmphioplus sp. schwimmtauchend beobachtet. 2.Amphioplus sp. lebt 20–35 cm tief in feinen Sandböden in Höhlen, die durch Röhren mit der Oberfläche verbunden sind. 3. Das Nahrungsfangverhalten, Bau und Funktion der Röhren und Höhlen werden beschrieben. 4. Das Verhalten des Schlangensternes wird als eine Anpassung an einen bestimmten Sedimenttyp diskutiert und mit anderen Arten verglichen.

Description / Table of Contents: Zusammenfassung 1. Die Eier von Dorsch (Gadus morhua L.), Flunder (Pleuronectes flesus L.) und Scholle (Pleuronectes platessa L.) der westlichen Ostsee wurden unter kombinierten Salzgehalts-Temperaturbedingungen (0°–16° C, 7‰–42‰ S) erbrütet. Es wurde untersucht, inwieweit die Embryonalentwicklung durch das Zusammenwirken von Temperatur und Salzgehalt beeinflußt wird. 2. Die optimalen Temperatur- und Salzgehaltsbereiche für die Erbrütung von Dorsch, Flunder und Scholle wurden festgestellt. Für den Dorsch konnten drei Versuche mit unterschiedlichem Material durchgeführt werden. Die optimalen Temperaturund Salzgehaltskombinationen für die Erbrütung von Dorscheiern betrugen: (a) 6°–8° C bei 25‰–30‰ S, (b) 4° C bei 20‰–33‰ S und (c) 4°–6° C bei 33‰ S. Für die Flundereier wurde als optimale Temperatur-Salzgehaltskombination 4° C und 33‰ S gefunden. Die untersuchten Scholleneier entwickelten sich bei 6° C und 20‰ S am besten. 3. In nicht-optimalen Temperatur- und Salzgehaltsbereichen war ein Absinken der Überlebensrate und verstärktes Auftreten morphologischer Anomalien an Embryonen und Larven zu verzeichnen. Als charakteristische Schädigungen traten Verkrümmungen der caudalen Körperregion auf. Larven, die in schwach salzigem Wasser gehalten wurden (20‰ und 15‰ S), litten an Dottersackquellung, was bei den Flunderlarven zu Kieferdeformationen führte. 4. Als wahrscheinliche Ursache für die Verkrümmungen und Verwachsungen des Schwanzes wurde ein durch extreme Temperaturen allgemein gestörtes Zusammenwirken der Enzyme diskutiert. 5. Die Wirkung hoher und niedriger Salzgehalte wurde in der Diskussion auf eine Störung im embryonalen Stoffwechsel zurückgeführt, die durch Änderung im Ionenmilieu der Zelle hervorgerufen wird. 6. Mit zunehmender Aussüßung des Erbrütungswassers konnte bei allen untersuchten Eiern Entwicklungsverlangsamung beobachtet werden. Bei hohen Erbrütungstemperaturen wurden die Unterschiede in der Entwicklungsgeschwindigkeit geringer. 7. Der für die Erbrütung optimale Salzgehalt änderte sich in Abhängigkeit von der Inkubationstemperatur. Ebenfalls war die optimale Erbrütungstemperatur in Abhängigkeit vom Salzgehalt des Erbrütungsmediums veränderlich. Extrem niedrige Salzgehalte (15‰ und 20‰ S) wurden im Bereich der Optimaltemperaturen oder bei niedrigen Temperaturen besser ertragen. 8. Bei allen drei untersuchten Fischarten wurde das Auftreten von Brackwasserrassen in der Ostsee erörtert und für wahrscheinlich gehalten.

Description / Table of Contents: Zusammenfassung 1. Die Vertikalverteilung der makroskopischen Algen im Helgoländer Sublitoral wurde an fünf Tauchprofilen von insgesamt 7200 m Länge untersucht. Weitere Tauchgänge wurden durchgeführt, um auch seltenere Arten zu erfassen. 2. Zwischen 0,5 und 1,5 m Tiefe bildenLaminaria digitata undL. saccharina eine geschlossene Vegetation, zwischen 1,5 und 4 mL. hyperborea. Mehrjährige Exemplare vonL. digitata undL. saccharina kommen nicht unterhalb von 3 m Tiefe vor,L. hyperborea wurde bis 8 m Tiefe gefunden. 3. Insgesamt wurden von 1965 bis 1970 im Helgoländer Sublitoral 66 Algenarten bzw. nicht weiter identifizierte Gattungen gefunden (Tab. 2). 38 Arten kamen in mehr als acht der untersuchten 1232 Quadrate (25×25 cm) vor (Tiefenverteilung in Abb. 10). Die sublitorale Algenvegetation erstreckt sich bei Helgoland bis 15 m Tiefe. Durch Vergleich mit Daten von anderen Küsten wurden zwei Artengruppen herausgestellt, deren untere Tiefengrenzen einerseits im oberen, andererseits im unteren Drittel des Sublitorals zu finden sind (Tab. 5).

Description / Table of Contents: Summary 1. The development of the pericentral cells, lateral wings, and primary cortex is briefly described in the rhodophyceanOsmundaria prolifera Lamouroux. 2. During subsequent development of the blades, a large part of the outer margins of the lateral wings is lost, presumably by sand abrasion. 3. The loss of the lateral wings appears to stimulate the primary cortex into meristematic activity, thereby producing a secondary cortex, attaining a thickness of up to 0.5 cm. 4. Secondary cortex formation in this species produces leathery, terete stipes which may be an adaptation towards perennation.

Description / Table of Contents: Zusammenfassung 1. Der Gehalt an Bakterien, speziell der coliformen Abwasserbakterien des Meerwassers, wurde im Bereich der Insel Sylt in den Jahren 1967/68 untersucht. 2. Keimzahl und Colititer der Wasserbereiche um Sylt liegen weit unterhalb der von den hygienischen Aufsichtsbehörden als zulässig anerkannten Höchstwerte mit Ausnahme der Bereiche von ca. 500 m Breite beiderseits der Auslässe, die das Abwasser der in das Wattenmeer entwässernden Kläranlagen ableiten. 3. Die Keimzahl ist am Ufer des Wattenmeeres etwa dreimal höher als am Weststrand, am Weststrand etwa zehnmal höher als im uferferneren Meerwasser westlich Sylt. Der Coliformentiter unterscheidet sich in den drei Wasserbereichen jeweils um eine Stufe, d. h. am Wattufer ist die mittlere Coliformen-Konzentration etwa zehnmal höher als am Weststrand, am Weststrand etwa zehnmal höher als in der offenen See. 4. Es besteht eine Abhängigkeit der Bakterienkonzentration von den Gezeiten. Am Weststrand wurden die höchsten Coliformen-Konzentrationen bei Flut gefunden, im Wattenmeer bei Ebbe. Es wird gefolgert, daß die Kontamination des Wattenwassers mit Abwasserbestandteilen vermittels des Gezeitenstromes auch das Wasser an der Westseite der Insel (Hauptbadestrand) beeinflußt. 5. Es betehen deutliche jahrezeitliche Unterschiede der Bakterienkonzentration in den drei genannten Wasserbereichen. Die Keimzahl ist im Sommer in der freien See und am Weststrand niedriger als im Winter. Die Coliformen-Konzentration ist im Sommer in allen Bereichen niedriger als im Winter. Die im Sommer wegen des Fremdenverkehrs stark erhöhte Abwasserbelastung des Sylter Wattenmeeres wird offenbar sehr gut kompensiert dadurch, daß das Seewasser im Sommer eine grö\ere Selbstreinigungskraft besitzt als im Winter. 6. Die Wasserproben des Weststrandes, die mit je zwei verschiedenen Nährböden auf ihre Keimzahl hin untersucht wurden, zeigten einen charakteristischen jahreszeitlichen Unterschied der Bakterienqualität: Unter Zugrundelegung der auf Seewassernährboden erzielten Keimzahl (als 100%) betrug die auf Süßwassernährboden erzielte Keimzahl im Winter 63%, im Sommer dagegen 18%. Das weist darauf hin, daß terrigene (auf Süßwassernährboden vermehrungsfähige) Bakterien im Sommer eine kürzere Überlebenszeit haben als im Winter.

Description / Table of Contents: Summary 1. An improved type of bubble-pump and an apparatus for producing continuous water currents, designed especially for utilization of planktonic food, are described. 2. The operation of the apparatus is easy; current speeds can be regulated from 0 to about 1/2 m/sec. 3. The apparatus can be used for experiments on small animals and plants, especially sessile and hemisessile forms. 4. BryozoansFarrella repens, Conopeum seurati, andC. reticulum, exposed to water currents at 15° C, exhibited no preferred growth direction relative to the current direction. 5. In fast currentsFarrella repens andElectra monostachys covered their substratum densely with zooids. 6. In slow currentsElectra monostachys andE. pilosa revealed positive rheotropic growth responses. 7. Slow water currents appear to stimulateElectra pilosa to form erect colony parts. 8. Water currents probably influence the development of ball-formed colonies inElectra pilosa formaerecta. The ball-form may be the result of an interaction between retarding effects of strong water currents at the periphery and stimulating effects of slow water currents in the interior parts of the ball.

Description / Table of Contents: Summary 1. Growth rates of populations started with adultEuterpina acutifrons fed on 16 different unicellular algae, and 2 mixtures of these algae, were compared. Only algae of medium size can support growth rates as high as those obtained in the mixture. Smaller algae (6–7 µ) or wider ones (〉 16 µ) give lower rates or do not support adult survival. 2. Of 5 algae tested, only those of medium size support all developmental stages from egg to adult ofEuterpina acutifrons. These results show that the size of food is one of the factors limiting the production of copepods under laboratory conditions. 3. By feeding adult females ofEuterpina acutifrons onPlatymonas suecica at various concentrations, it was demonstrated that, when the food concentration increases, the rate of ingestion and the egg production of the copepod increases thereby reaching a plateau, while the rate of filtration decreases. 4. The same relation is found for the 5 algae tested in regard to ingestion and filtration activities. However, for the 5 algal species, the concentration at which the plateau is reached, and the value of ingestion at this plateau, are quite different. 5. When feeding femaleEuterpina acutifrons in excess unicellular solutions of the 5 algae or a mixture of all the algae used, egg production and adult life span differs according to the type of the food algae. Algal species which result in low egg production and short adult life span are most intensively ingested in terms of biomass. 6. By increasing the number of algal species and their concentration in the culture solution, we were able to cultivate some additional pelagic copepods through several generations.

Description / Table of Contents: Summary 1. Larvae ofCancer irroratus were raised in the laboratory from the first zoeal stage to the first crab stage. Five zoeal stages and one megalops stage were observed during development to the first crab stage. 2. The larvae developed to the megalops stage in salinities of 20 ‰, 25 ‰, 30 ‰ and 35 ‰, and at temperatures of 10°, 15° and 20° C. The megalops metamorphosed in all the four salinities at 15° C, and in 25 ‰ at 20° C. A temperature-salinity combination of 15° C and 30 ‰ S was found to allow maximum survival of larvae until the crab stage. The different salinities do not seem to affect greatly the duration for zoeal development, megalops development and total development to the crab stage at 15° C. 3. The larvae ofPanopeus herbstii were also raised to the first crab stage in the laboratory at 20° and 25° C and 32 ‰ S. There were four zoeal stages and one megalop stage during complete development in the laboratory. 4. A re-circulating sea water system has been designed and fabricated for cultivation of crab larvae under controlled environmental conditions in the laboratory. The larvae ofC. irroratus andP. herbstii, cultured in the sea water system, completed their development to the first crab stage.

Description / Table of Contents: Summary 1. The behaviour of pure cultures of marine micro-organisms in sterilized sediments was studied by inoculation of the supernatant liquid media with mobile bacteria. 2. The largest numbers of bacteria developed at the sediment surface down to 4 mm depth and not in the supernatant liquid, in spite of the fact that the supernatant liquid only was inoculated. 3. Most of the strains tested reached the bottom of the sediment within a few days. 4. Strain 31 did not reach the bottom of the sediment in case of dry sterilisation of the sediment column. 5. Strain 31 developed in all media different coloured variants, except in media with additional sediment extract where the original red colour remained. In these media bacteria reached well to the bottom of the sediment columns tested. 6. The original organic matter of the sediment fractions tested was usually sufficient to support growth of the bacteria examined. After several days of incubation, bacteria reached the same numbers as was the case with additional nutrient substances. 7. Active movement of bacteria through fine grained sediments is possible. Population of sterile sediments from the supernatant water column is possible and progresses rapidly. 8. Decrease in bacteria numbers with increasing sediment depth is not connected to nutrient concentration.

Description / Table of Contents: Summary 1. The scallopPecten maximus (L.) can be conditioned in the laboratory to produce ripe gametes at times other than its normal spawning seasons. 2. The spawning stimulus consists of taking the scallop out of water for a period of approximately 2 h. Spawning occurs within 2 to 4 h of re-immersion in water. 3. More larvae and a higher proportion of normal larvae are produced by eggs incubated at low density levels. 4. The higher sperm concentrations produce fewer larvae and higher percentages of abnormal larvae than the lower concentrations. 5. Eggs incubated at 7 per cm2 bottom area produce very few abnormal larvae but large numbers of normal larvae can be produced more efficiently by incubating at a density level of 700 eggs per cm2 although a higher percentage of abnormal larvae must be tolerated.

Description / Table of Contents: Summary 1. Nutritive and temperature stresses in experiments cause a decline in general body condition and dry weight ofMytilus edulis L. Carbohydrate and protein are lost from the body; these losses are greater from the germinal (mantle) than from the somatic (non-mantle) tissues. There is a more rapid loss of carbohydrate than of protein.M. edulis is able to maintain and continue maturation of the gametes in spite of this considerable utilisation of general body reserves. 2. The greater the degree of stress imposed on the test animals the greater is the utilisation of carbohydrate and protein. However, the mussels maintain a balance between these two components so that, at any one time, the carbohydrate to protein ratio does not differ between individuals subjected to different degrees of stress. 3. During the cultures there was a decline in oxygen consumption. Nitrogen excretion either increases or slightly decreases. The ratio oxygen consumed to nitrogen excreted declines in all experiments, indicating an increased use of protein as an energy substrate. The greater the degree of stress imposed upon the test animal, the greater the rate of decline of the O:N ratio. The values for this ratio suggest thatM. edulis normally utilises carbohydrate or fat substrates, though proteins may also be utilised in response to stress. 4. Indices of physiological condition should prove useful in determining the degrees of stress that are experienced by lamellibranchs under cultivation. In order to measure the effects of stress, knowledge of the normal seasonal variations in physiological indices is needed, to serve as a “base-line” with which induced changes in condition may be compared.

Description / Table of Contents: Summary 1. A diet rich in proteins is necessary for the growth of very youngMugil auratus andM. capito (standard length: 21 mm). As soon as the natural change of diet occurs, a smaller quantity is sufficient. 2. The nature of proteins, incorporated in the food, does not seem to influence conversion rates. 3. Under conditions of complete starvation, a solution of urea at a concentration of 4 g/l reduces weight loss in youngMugil capito (1.5 % instead of 23 % loss after 9 day's starvation). 4. At 15° C, 10 gMugil auratus require a daily maintenance ration of 0.92 Cal; a ration of 1.8 Cal facilitates a higher growth efficiency (7 % in 3 weeks). 5. The addition of non-assimilable components reduces the rate of utilization of assimilable food substances. 6. Salinity influences food conversion rate. A salinity of 20 ‰ affords maximum growth and highest efficiency of food turnover.

Description / Table of Contents: Summary 1. Four crabs,Rhithropanopeus harrisii, Hexapanopeus angustifrons, Libinia emarginata andCallinectes sapidus, were reared from the egg to the first crab stage on freshly hatchedArtemia salina nauplii from two sources: salt pools in California, and the Great Salt Lake in Utah. All larvae showed better survival on California nauplii than on Utah nauplii. The crab larvae fed on California nauplii showed normal development, whereas allR. harrisii megalopa and someH. angustifrons showed a particular set of abnormalities. 2. There is evidence that the difference in normality and survival of developmental stages of the four species of crabs may be due to a difference in the quantity of DDT inArtemia nauplii from California and from Utah. There was approximately three times as much DDT inArtemia nauplii from Utah as in the nauplii from California. The nature of the abnormalities which appeared in larvae fed on Utah nauplii resembled DDT poisoning which has been reported in juvenile and adult crabs.

Description / Table of Contents: Summary 1. The continuing increase in demand for shrimps and prawns in the world markets, at a time when the basic understanding of the biology and ecology of Penaeid shrimps permits a more precise definition of the parameters of their culture, has provoked enlightened support of research and a considerable investment in field evaluation by several industry and government agents in the United States in an effort to establish a viable cultural enterprise. 2. Reproduction biology, spawning and larviculture, are reviewed here as they apply to the production of postlarvae ofPenaeus duorarum, P. setiferus, andP. aztecus. Intensive culture in high-density postlarvae-stocked ponds, and extensive culture by postlarval seeding of natural embayments are compared and evaluated. 3. Management practices as exercised in the maintenance of high productivity conditions in the ponds, and embayments; feeding with appropriately formulated rations; and harvesting techniques are discussed for both cultural systems. 4. Potential growth rates, product yields and production costs can now be postulated, and the economic return on investment from a commercial venture can now be estimated.

Description / Table of Contents: Summary 1. The large-scale routine culture of the larvae ofOstrea edulis for 31 consecutive weeks in 1969 showed marked fluctuations in the growth rate of the larvae. 2. In the first 20 weeks the periods of reduced growth coincided with those times when the sea water was highly turbid. 3. The concentration of dissolved zinc in the sea water varied between 0.5 and 470 µg/1. Laboratory experiments showed that the higher levels would be sufficient to reduce growth. 4. A bloom ofPhaeocystis pouchetti in the river reduced larval growth at the end of May. 5. In July an outbreak of a bacterial disease caused a number of larval cultures to collapse. 6. The use of mixed species of algae as food gives a more rapid growth of the larvae, an enhanced proportion metamorphosing, and more vigorous spat compared with feeding on one species of alga.