Factors influencing the start of development in Daphnia pulex winter eggs [Translation from: Biological Reviews Vol. 13, 24-26, 1951]

The winter eggs of Daphnia pulex, after passing safely through the winter , develop and hatch in the spring, multiplying by themselves, while some males emerging among them with the changes in environment produce fertile eggs, which are universally known as winter eggs . This study researches the factors governing the development of winter eggs through experiments.

Die bewirtschafteten Fischbestände im Nordwestatlantik. Eine Einschätzung des Wissenschaftsrates der NAFO vom Juni 1999

Die Situation der bewirtschafteten Fischbestände im NAFO-Gebiet hat sich im Jahr 1998 im Vergleich zu 1997 nicht verändert. Alle Bestände auf der Grand bank (Gebiet 3LNO) bis auf die Gelbschwarzflunder, deren Bestand sich weiter vergrößerte, bleiben auf niedrigstem Niveau mit wenig Aussicht auf eine kurzfristige Erholung. Auch die Bestände auf der Flämischen Kappe (Gebiet 3M) sind mit Ausnahme der Garnelen (Pandalus boreals) in der gleichen Situation.

Mehrjährige Ausrichtungsprogramme für die EG-Fischereiflotte

Eine internationale Zusammenarbeit in der Fischereiforschung und im Management zur Erhaltung und Nutzung der Fischbestände erwies sich aufgrund der zunehmenden Befischung schon zu Beginn dieses Jahrhunderts als notwendig, da Fischbestände teils wegen ihrer Ausdehnung, teils wegen ihres Wanderverhaltens selten auf die Gewässer eines Staates begrenzt sind.

Reducing feed costs in semi-intensive finfish culture: an update on mixed feeding schedules and an idea for enhancing endogenous food supply in ponds

Some interesting ideas on improving the cost-effectiveness of feeding in semi-intensive finfish aquaculture are presented.

Production of freshwater prawns in the Mekong Delta

Currently there are 2 sources of freshwater prawn Macrobrachium rosenbergii production in Vietnam - natural production from the rivers and canals and aquaculture production from ponds and ricefields. An account is given of the production of this prawn in the Mekong Delta. The prawns are harvested primarily by a common small scale method using shelter traps. The total annual freshwater prawn production in Vietnam during 1985-90 was reported to vary from 5000 to 8000 tons, most of it from natural fisheries; although there are no official statistics on the production of farmed prawns, the amount is believed to be very small. The grow-out system includes intensive monospecies pond culture, and semi-intensive or extensive integrated rice-prawn or vegetable-prawn culture.

The evolution of body muscle composition of the African catfish (Clarias gariepinus) (Burchell 1822)

Changes in body muscle composition of Clarias gariepinus were studied in fish reared from 1.08 g to 383 g mean body weight in a 201-day culture period. Changes in the amount of protein content, dry matter and ash free dry matter in the muscle tissue can be described as a function of body weight. The percentage of protein content was observed to be higher in bigger fish. Fat content was low throughout the fingerling stage. Specific growth rate decreased significantly at 400 g mean body weight (P<0.05) while feed conversion rate increased. The conclusion, based on the culture conditions in this study, is that the optimal weight for harvesting C. gariepinus is 400 g.

PICES Press, Vol. 19, No. 1, Winter 2011

•2010 PICES Science: A Note from the Former Science Board Chairman (pp. 1-4) •2010 PICES Awards (pp. 5-7) •The First Year of FUTURE: A Progress Report (pp. 8-13) •New Chairmen in PICES (pp. 14-19) •Pacific Ocean Interior Carbon Data Synthesis, PACIFICA, in Progress (pp. 20-23) •2011 PICES Calendar (p. 23) •Ecosystems 2010: Global Progress on Ecosystem-based Fisheries Management (pp. 24-26) •PICES 2010 Rapid Assessment Survey (pp. 27-29) •PICES Workshop on “An Introduction to Rapid Assessment Survey Methodologies for Application in Developing Countries” (pp. 30-31) •The State of the Western North Pacific in the First Half of 2010 (pp. 32-34) •PICES Interns (p. 34) •The State of the Bering Sea in 2010 (pp. 35-37) •The State of the Northeast Pacific in 2010 (pp. 38-40)

On farm trial of Bangladesh Fisheries Research Institute (BFRI) evolved two aquaculture technologies

Two BFRI evolved aquaculture technologies - integrated rice fish farming and carp polyculture with over-wintered fingerlings under different stocking densities were tested during 2003-04. The study was coordinated with two local NGOs namely NICHAITA and JNDP, Muktagacha, Mymensingh. Integrated rice fish farming technology was demonstrated in 9 plots each having an area between 60-100 dec. during boro season. Fifteen days after transplantation of rice seedlings, fingerlings of rajpunti (Barbodes gonionotus) of 7-10 g of individual weight were stocked in the rice fields at the density of 3,000 (T1), 3,750 (T2) and 4,500/ha (T3). The corresponding final weight of fish after three and half months in treatments 1, 2 and 3 were 110±14.21, 101±16.55 and 86±22.28 g, respectively. The mean weight of fish in treatments 1 and 2 was significantly higher than treatment 3. Fish production obtained from treatments 1, 2 and 3 were 218.16±18.29, 239.70±25.11 and 236±24.66 kg/ha, respectively. On-farm demonstrations of carp polyculture using over-wintered fingerlings rohu (25-28 g), catla (24-26 g), mrigal (21-26 g) and grass carp (20-24 g) under different stocking densities were undertaken in nine earthen ponds (1,200-1,600 square meters) for a period of six months at three different stocking densities. The stocking densities of treatment 1 (T1), treatment 2 (T2) and treatment 3 (T3) were 2,000, 3,000 and 4,000/ha, respectively. Fish were fed with rice bran and mustard oil cake (3:1). Soft green grass and banana leaves were provided mainly for grass carp. At harvest, the production obtained in treatments 1, 2 and 3 were 2,325±74.75, 2,620±49.66 and 2,982± 171.52 kg/ha, respectively. The results demonstrated higher growth of fish in treatment 1 than those of treatments 2 and 3. However, treatment 3 contributed relatively higher production than those of treatments 1 and 2, whereas, highest net benefit was received from treatment 2.

Oxygen consumption under copper and zinc stress in Perna viridis

The rate of oxygen consumption by Perna viridis pre-exposed to copper and zinc was studied. Those test individuals pre-exposed to various zinc concentrations showed variability in oxygen consumption irrespective of concentrations and pre-exposure period. While those animals pre-exposed to various copper concentrations registered decrease in oxygen consumption at concentrations above 0.06 p.p.m. copper, pre-exposure to concentrations below 0.02 p.p.m. copper did not result in any clear cut change in the rate of oxygen consumption.