Effect of hatching time and starvation on morphometrics and biochemical composition of Octopus tetricus paralarvae

2021 ◽  
Author(s):  
Stefan Spreitzenbarth ◽  
Andrew Jeffs
2012 ◽  
Vol 70 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Rosario Domínguez-Petit ◽  
Patrick Ouellet ◽  
Yvan Lambert

Abstract Domínguez-Petit, R., Ouellet, P., and Lambert, Y. 2013. Reproductive strategy, egg characteristics and embryonic development of Greenland halibut (Reinhardtius hippoglossoides). – ICES Journal of Marine Science, 70: 342–351. Despite the commercial importance of Greenland halibut (GH), important gaps exist in our knowledge of the reproductive and early life stage biology for this species. The present study examined through laboratory experiments the spawning strategy, realized fecundity, egg characteristics, biochemical composition, and embryonic development of GH. The results confirmed the hypothesis that GH is a single-batch spawner producing large eggs, resulting in low realized fecundity. Embryonic development and hatching time are highly dependent on incubation temperature; 50% hatching occurred after 46, 30, and 24 days at 2, 4, and 6°C, respectively. Few changes in the biochemical composition of the eggs are observed during embryonic development. Newly hatched larvae are not well developed, having a large yolk sac, no pigmentation and incomplete development of the jaws. Egg specific density confirmed the mesopelagic distribution of the eggs at sea. However, important buoyancy changes occurring in the last 3–4 days before hatching indicate that larvae hatch higher in the water column. These results are important for understanding advection and dispersion processes of GH eggs and larvae and the connectivity between spawning grounds and nursery areas.


Author(s):  
Alexander S. Lelekov ◽  
Anton V. Shiryaev

The work is devoted to modeling the growth of optically dense microalgae cultures in natural light. The basic model is based on the idea of the two-stage photoautotrophic growth of microalgae. It is shown that the increase in the intensity of sunlight in the first half of the day can be described by a linear equation. Analytical equations for the growth of biomass of microalgae and its macromolecular components are obtained. As the initial conditions, it is assumed that at the time of sunrise, the concentration of reserve biomass compounds is zero. The simulation results show that after sunrise, the growth of the microalgae culture is due only to an increase in the reserve part of the biomass, while the structural part practically does not change over six hours. Changes in the ratio of the reserve and structural parts of the biomass indicate a change in the biochemical composition of cells.


2015 ◽  
Vol 51 (4) ◽  
pp. 39-45
Author(s):  
N. I. Kirpenko ◽  
O. M. Usenko ◽  
T. O. Musiy

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