scholarly journals Cod’s Journey Back Home—From Birth to Nursery

2021 ◽  
Vol 9 ◽  
Author(s):  
Clarissa Akemi Kajiya Endo ◽  
Frode B. Vikebø ◽  
Natalia A. Yaragina ◽  
Solfrid Sætre Hjøllo ◽  
Leif Christian Stige
Keyword(s):  
Yolk Sac ◽  
Living Conditions ◽  
Ocean Currents ◽  
Adult Fish ◽  
Ocean Water ◽  
Nursery Areas ◽  
Food Reserve ◽  
Eggs And Larvae

Adult cod swim hundreds of kilometers away from home to release their eggs into the ocean water. After some days, tiny larvae hatch from the eggs. At first, the larvae have a small food reserve to sustain them during their first days of life. Soon after emptying the yolk-sac, the larvae must find food on their own. Both eggs and larvae are carried by the ocean currents and they experience large changes in conditions as they drift back to the nursery areas where their parents came from, where the larvae grow up to become adult fish. Our research on cod indicates that the number and location of cod larvae are associated with the size of the spawning adults; and that the number of larvae influences how many cod will grow to be recruits. So, it is important to also know the living conditions of the parents before they spawn, which will be important for the survival of their offspring.

scholarly journals Some features of embryonic development of eggs and larvae of three stripe rockfsh Sebastes trivittatus (Sebastidae) at Primorye (Japan Sea)

2018 ◽  
Vol 195 ◽  
pp. 146-150
Author(s):  
V. P. Gnyubkina ◽  
A. I. Markevich
Keyword(s):  
Embryonic Development ◽  
Water Temperature ◽  
Japan Sea ◽  
Yolk Sac ◽  
Internal Layers ◽  
External Layer ◽  
Frontal Part ◽  
June July ◽  
Late Stages ◽  
Eggs And Larvae

Later embryonic development ofSebastes trivittatuspasses in 20 days under water temperature 10 оС (in June-July). During this period, the embryos ofS. trivittatusincrease in diameter from 0.1 mm to 1.3 mm and change their shape from spherical to elliptical. Within gonads of pre-hatching females, the embryos have different stages: from prelarvae on late stages of development in the internal layers to pre-hatching larvae in the external layer. The pre-hatching larva hasTL4.1 mm, 5–6 melanophores on the top of head, 20 melanophores in ventral row, some melanophores on peritoneum, and oil globule in the frontal part of intestine; its notochord is not flexed, yolk sac is absent, body myotomes are poor visible, number of tail myotomes is 24.

A Study of Diffusional Permeability of Water, Sodium and Chloride in Yolk-Sac Larvae of Cod (Gadus Morhua L.)

1989 ◽  
Vol 147 (1) ◽  
pp. 125-132 ◽  
Author(s):  
PETER TYTLER ◽  
MICHAEL V. BELL
Keyword(s):  
Gadus Morhua ◽  
Sea Water ◽  
Fish Larvae ◽  
Yolk Sac ◽  
Adult Fish ◽  
Permeability Coefficients ◽  
Osmotic Permeability ◽  
Marine Fish Larvae ◽  
Diffusional Permeability ◽  
Previous Hypothesis

1. The fluxes of 3H2O, 22Na and 36Cl were simultaneously measured in yolk-sac larvae of cod (Gadus morhua L.) in 34‰ sea water at 4.5°C. 2. The rates of turnover of all three isotopes were higher than in adult fish. Diffusional permeability coefficients, which relate ion fluxes to surface area, were however lower, indicating that larvae are less permeable than adults. Furthermore, there is close agreement between the diffusional and osmotic permeability coefficients, which supports a previous hypothesis that relatively low drinking rates in marine fish larvae are a consequence of low integumental permeability. 3. Estimates of the sodium and chloride concentrations derived from the equilibrium levels of 22Na, 36Cl and 3H2O indicate that yolk-sac larvae of cod regulate their body fluids hypotonic to sea water. Also, the ionic concentrations of the tissues of yolk-sac cod larvae are similar to those of adults.

Distribution and drift of Atlantic cod (Gadus morhua) eggs and larvae on the northeast Newfoundland Shelf

1997 ◽  
Vol 54 (3) ◽  
pp. 670-685 ◽  
Author(s):  
P Pepin ◽  
J A Helbig
Keyword(s):  
Spatial Patterns ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stage I ◽  
Surface Currents ◽  
Adult Fish ◽  
Northern Limit ◽  
Mean And Variance ◽  
The Mean ◽  
Eggs And Larvae

We present the results of a study designed to ascertain the importance of variations in transport of cod eggs and larvae on the northeast Newfoundland Shelf. The distribution of cod eggs and larvae is described from a series of ichthyoplankton surveys. The mean and variance in surface currents were estimated from five experiments in which clusters of drogued satellite-tracked drifters were released at the presumed northern limit of the stock's range. These data were used to project the patterns of drift both backward and forward in time and thus the possible sources and destinations of eggs and larvae. Considering the development from the youngest (stage I) to the oldest stages (larvae), we saw a north-to-south and an offshore-to-inshore progression in spatial patterns of spawning and a continuing increase in the overall level of dispersion with increasing age of offspring. The data do not support the hypothesis that coastal or offshore areas represent simple sources or sinks of cod eggs and larvae. Transport plays an important but highly variable role that is coupled to the spawning distribution of adult fish and the availability of suitable conditions or habitats when the young begin to undergo metamorphosis and settle.

Eggs and Larvae of the Four-winged Flying Fish, Hirundichthys speculiger (Valenciennes)

1954 ◽  
Vol 5 (1) ◽  
pp. 64 ◽  
Author(s):  
ISR Munro
Keyword(s):  
Sea Water ◽  
New South ◽  
Yolk Sac ◽  
Specific Identification ◽  
South Wales ◽  
Flying Fish ◽  
Egg Membrane ◽  
Floating Objects ◽  
Eggs And Larvae ◽  
Early Larvae

The eggs of the four-winged or mirror-finned hirundine flying fish, Hirundichthys speculiger (Valenciennes), are spawned off the New South Wales coast in masses attached to floating objects. The eggs are heavier than sea-water and employ floating objects to buoy them at the surface. The eggs adhere by means of cords of long filaments attached to one pole of the egg membrane. Specific identification of the eggs is based on the arrangement of these filaments. A sample of naturally spawned eggs was maintained in culture for 15 days. The larvae appeared to feed on ciliate protozoans after absorption of the yolk sac. The eggs and early larvae are described and illustrated.

Study on zooplankton diversity with physicochemical parameters of Hukal River, Kodinar Gujarat, India.

2017 ◽  
Vol 6 (2) ◽  
pp. 5286
Author(s):  
Nikul B. Chavada
Keyword(s):  
River Water ◽  
Significant Role ◽  
Physicochemical Parameters ◽  
Ocean Currents ◽  
Abiotic Factor ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Plankton Diversity ◽  
Eggs And Larvae

Plankton refers to plants and animals that drift with the ocean currents and fresh river water. they habitants in the open waters of the sea and fresh river water. Zooplankton (from Greek zoon, or animal) are Small protozoans or metazoans (e.g. crustaceans and other animals) that feed on other plankton and telonemia. Some of the eggs and larvae of larger animals, such as fish, crustaceans and annelids, are included in Zooplankton. Physico-chemical parameters are very important factors that play a significant role in river zooplankton diversity and fluctuation. We evaluated impact of Abiotic factor on plankton diversity during pre, middle and post winter analysis of Hukal River.

scholarly journals Ontogenetic development of Heterocharax macrolepisEigenmann (Ostariophysi: Characiformes: Characidae) with comments on the form of the yolk sac in the Heterocharacinae

2014 ◽  
Vol 12 (2) ◽  
pp. 353-363 ◽  
Author(s):  
George M. T. Mattox ◽  
Martin Hoffmann ◽  
Peter Hoffmann
Keyword(s):  
Standard Length ◽  
Developmental Stages ◽  
Yolk Sac ◽  
Morphological Features ◽  
Aquarium Trade ◽  
Neotropical Fishes ◽  
Early Developmental Stages ◽  
Early Developmental ◽  
Eggs And Larvae ◽  
Notochord Length

Fishes in early developmental stages frequently have morphological features that differ from those of adult stages, and many characters found later in ontogeny are not available in initial stages. Hence, morphological descriptions of early stages are useful to provide information for the identification of eggs and larvae, a knowledge still restricted among Neotropical fishes. We studied the development of Heterocharax macrolepis, a heterocharacine whose adult specimens from the aquarium trade were kept and spawned at around 23-24ºC. A developmental series of 51 specimens was preserved, ranging from 3.2 mm notochord length to 18.6 mm standard length, covering approximately the first 73 days post-hatching. We described the development of main morphological features emphasizing those useful in the identification of H. macrolepislarvae (i.e., appearance of preopercle spine and development of the pseudotympanum). We also compared H. macrolepis with photographs taken of live larval specimens of Gnathocharax steindachneri, recently included in the Heterocharacinae. Both species have a yolk sac with a small rounded projection directed posteroventrally. Although this information is not yet available for all pertinent taxa, the different yolk sac shape in other representatives of the Characiformes may indicate that this peculiar yolk sac represents an additional synapomorphy of the Heterocharacini.

Dispersion of vendace eggs and larvae around potential nursery areas reveals their reproductive strategy

2019 ◽  
Vol 64 (5) ◽  
pp. 843-855 ◽  
Author(s):  
Juha Karjalainen ◽  
Janne Juntunen ◽  
Tapio Keskinen ◽  
Saija Koljonen ◽  
Kristiina Nyholm ◽  
...  
Keyword(s):  
Reproductive Strategy ◽  
Nursery Areas ◽  
Eggs And Larvae

Egg and larval abundance and spawning localities of the anchovy (Engraulis australis) and pilchard (Sardinops neopilchardus) near Phillip Island, Victoria

1995 ◽  
Vol 46 (4) ◽  
pp. 735 ◽  
Author(s):  
FE Hoedt ◽  
WF Dimmlich
Keyword(s):  
Spatial Variability ◽  
Larval Abundance ◽  
Adult Fish ◽  
Spawning Area ◽  
Fish Spawning ◽  
The Mean ◽  
Eggs And Larvae

The distribution and abundance of the eggs and larvae of the anchovy (Engraulis australis) and pilchard (Sardinops neopilchardus) were determined for the waters near Phillip Island between May 1992 and January 1994. Eggs and larvae of both species were common in these waters, indicating that this region is an important spawning area for both species. Pilchard eggs and larvae occurred at sample stations in Bass Strait and in the western entrance to Western Port. Anchovy eggs and larvae were collected both within Western Port and at most plankton stations in Bass Strait. The mean density of anchovy eggs in Western Port differed markedly between the two spawning seasons, suggesting that the number of adult fish spawning therein can vary between years. Densities of pilchard eggs and of the larvae of both species exhibited considerable spatial variability in Bass Strait.

A Note on the Development of Eggs and Larvae of the Bogue, Boops Boops

1984 ◽  
Vol 64 (3) ◽  
pp. 729-731
Author(s):  
S. H. Coombs ◽  
C. E. Mitchell
Keyword(s):  
Sea Water ◽  
Adult Fish ◽  
Bottom Temperature ◽  
Bottom Trawling ◽  
Different Temperatures ◽  
Artificial Fertilization ◽  
Males And Females ◽  
Incubation Temperatures ◽  
Boops Boops ◽  
Eggs And Larvae

An opportunity was taken to carry out the artificial fertilization and incubation at different temperatures of eggs of the bogue, Boops boops (Linnaeus, 1758) during a cruise on R.V. 'Cirolana' organized by the Fisheries Laboratory, Lowestoft. Adult fish for use in the experiment were obtained by bottom trawling in 165 m depth of water at 43° 44' N02° 44' W on 10 May 1980 between 0449 and 0549 h GMT. The bottom temperature at the trawling position was estimated to be ~ 11 · 8 °C, based on measurements made at nearby stations. Eggs and milt from several males and females were added to a container of sea waterheld at approximately 11 °C; after 1 h the fertilized eggs were transferred as four separate subsamples each of approximately too eggs to clean sea water in the incubation beakers. Thesebeakers were then gradually acclimatized over a period of 2 h to the incubation temperatures of80, 131, 182 and 22·8°C.At all temperatures mortality was high during early embryonic development. At 228 °C all eggs were dead after 9J h of incubation at which time some of these specimens had formed a blastoderm cap, but with no sign of overgrowth of the yolk. In a few of the eggs held at 80 °C development proceeded normally until immediately before closure of the blastopore (~ 106 h after ferilization) when irregular vacuoles were seen in the area around the blastopore and development was disrupted; after 112 h of incubation all eggs held at 80 °C were dead.

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