Foraging behavior in early Atlantic cod larvae ( Gadus morhua ) feeding on a protozoan ( Balanion sp.) and a copepod nauplius ( Pseudodiaptomus sp.)

2000 ◽  
Vol 136 (3) ◽  
pp. 591-602 ◽  
Author(s):  
I. Hunt von Herbing ◽  
S. M. Gallager
Keyword(s):  
Foraging Behavior ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Copepod Nauplius ◽  
Atlantic Cod Larvae

Use of the microalga Pavlova viridis as enrichment product for the feeding of Atlantic cod larvae (Gadus morhua)

Aquaculture ◽  
2015 ◽  
Vol 438 ◽  
pp. 141-150 ◽  
Author(s):  
S. Rehberg-Haas ◽  
S. Meyer ◽  
M. Tielmann ◽  
S. Lippemeier ◽  
O. Vadstein ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Pavlova Viridis ◽  
Atlantic Cod Larvae ◽  
Enrichment Product

Annual and spatial variability in endo- and ectoparasite infections of North Sea cod (Gadus morhua Linnaeus, 1758) larvae, post-larvae and juveniles

2014 ◽  
Vol 59 (2) ◽  
Author(s):  
Foojan Mehrdana ◽  
Qusay Bahlool ◽  
Alf Skovgaard ◽  
Jesper Kuhn ◽  
Per Kania ◽  
...  
Keyword(s):  
Spatial Variability ◽  
North Sea ◽  
Gadus Morhua ◽  
Sea Water ◽  
Atlantic Cod ◽  
The North ◽  
Infection Pressure ◽  
High Prevalence ◽  
Atlantic Cod Larvae ◽  
The North Sea

AbstractA parasitological investigation was performed on a total of 5380 Atlantic cod larvae, post-larvae and small juveniles sampled from the North Sea during a period of five years. The copepod Caligus elongatus (Von Nordmann, 1832) and the nematode Hysterothylacium aduncum (Rudolphi, 1802) were found at a relatively high prevalence of infection (4.6% and 5.2%, respectively). The infection by both parasites showed annual and spatial variability. C. elongatus showed a higher prevalence in 1992 compared to the following years, whereas the prevalence of H. aduncum increased from 1992 to 2001.We observed a relation between parasite distribution and parameters such as latitude and water depth. Adult digeneans (Lecithaster gibbosus and Derogenes varicus) and larval cestodes were also found with lower infection rates. Since changes of infection levels coincided with increasing North Sea water temperature in the studied period, it is hypothesized that temperature may affect parasite population levels. However, it is likely that other environmental factors may contribute to the observed variations. Absence of infection intensities higher than one nematode per fish in small larvae and post-larvae suggests that host survival may be affected by a high infection pressure. The relatively high levels of infection in the younger stages of cod, and the annual/spatial variability of these infections should be considered in the understanding of the early life dynamics of the species.

scholarly journals Transcriptome profiling reveals exposure to predicted end-of-century ocean acidification as a stealth stressor for Atlantic cod larvae

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
F. H. Mittermayer ◽  
M. H. Stiasny ◽  
C. Clemmesen ◽  
T. Bayer ◽  
V. Puvanendran ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Gadus Morhua ◽  
Molecular Mechanisms ◽  
Atlantic Cod ◽  
Transcriptome Profiling ◽  
Direct Consequence ◽  
Differentially Expressed ◽  
Cellular Stress Response ◽  
Atlantic Cod Larvae ◽  
Developmental Asynchrony

AbstractOcean acidification (OA), a direct consequence of increasing atmospheric CO2 concentration dissolving in ocean waters, is impacting many fish species. Little is known about the molecular mechanisms underlying the observed physiological impacts in fish. We used RNAseq to characterize the transcriptome of 3 different larval stages of Atlantic cod (Gadus morhua) exposed to simulated OA at levels (1179 µatm CO2) representing end-of-century predictions compared to controls (503 µatm CO2), which were shown to induce tissue damage and elevated mortality in G. morhua. Only few genes were differentially expressed in 6 and 13 days-post-hatching (dph) (3 and 16 genes, respectively), during a period when maximal mortality as a response to elevated pCO2 occurred. At 36 dph, 1413 genes were differentially expressed, most likely caused by developmental asynchrony between the treatment groups, with individuals under OA growing faster. A target gene analysis revealed only few genes of the universal and well-defined cellular stress response to be differentially expressed. We thus suggest that predicted ocean acidification levels constitute a “stealth stress” for early Atlantic cod larvae, with a rapid breakdown of cellular homeostasis leading to organismal death that was missed even with an 8-fold replication implemented in this study.

scholarly journals Effect of enriched rotifers on growth, survival, and composition of larval Atlantic cod (Gadus morhua)

2006 ◽  
Vol 63 (2) ◽  
pp. 285-295 ◽  
Author(s):  
Heum Gi Park ◽  
Velmurugu Puvanendran ◽  
Anne Kellett ◽  
Christopher C. Parrish ◽  
Joseph A. Brown
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Dry Weight ◽  
Larval Survival ◽  
High Ratio ◽  
Oil Emulsion ◽  
Growth And Survival ◽  
Whole Cells ◽  
Atlantic Cod Larvae ◽  
Spray Dried

Abstract Recently, the nutritional requirements of marine finfish larvae have received considerable attention, and studies have shown that docosahexaenoic acid (DHA) affects the growth and survival of marine finfish larvae. We investigated the effects of different rotifer diets containing variable amounts of DHA on the growth and survival of larval Atlantic cod (Gadus morhua L.). Four different commercial rotifer enrichment formulations were used: spray-dried whole cells composed of Crypthecodinium sp. (ED1), spray-dried whole cells of Schizochytrium sp. (ED2), an oil emulsion (ED3) and ED1, and dried Chlorella at a 7:3 ratio by weight (ED4). The resultant rotifers contained a similar concentration of DHA (1.1–1.6% DW), but the level of DHA differed in proportion to EPA for each enrichment, and was designated ER1–4. Twelve 30-l aquaria were used with three replicates per treatment. Larvae were fed with rotifers from 3 to 43 days post-hatch (dph) at 4000 prey l−1. At the end of the experiment, no significant differences were found in body length and dry weight between the larvae reared on ER1 and ER2. However, larvae reared on ER3 were significantly smaller (both in length and weight) than larvae reared on ER1 and ER2. Larval survival on the ER2 treatment at 43 dph was significantly higher than on the other three treatments. Our results showed a positive effect of rotifer DHA proportions on growth and survival of cod larvae, and demonstrated that Atlantic cod larvae require a high ratio of dietary DHA to EPA.

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