Foraging behaviour of Atlantic cod (Gadus morhua) larvae in relation to prey concentration

2002 ◽  
Vol 80 (4) ◽  
pp. 689-699 ◽  
Author(s):  
V Puvanendran ◽  
L L Leader ◽  
J A Brown
Keyword(s):  
Standard Length ◽  
Gadus Morhua ◽  
Foraging Behaviour ◽  
Atlantic Cod ◽  
Extended Period ◽  
Prey Concentration ◽  
Intensive Rearing ◽  
Gut Fullness ◽  
Atlantic Cod Larvae ◽  
Tremendous Amount

In spite of a tremendous amount of research on Atlantic cod (Gadus morhua) larvae, no information is available on the development of foraging behaviour over an extended period. We investigated the ontogeny of foraging behaviour of Atlantic cod larvae exposed to different prey concentrations from hatching to metamorphosis. The objective of this work was to determine if their foraging behaviour is influenced by prey concentration. Rotifers and (or) Artemia sp. were used as prey at concentrations of 0, 500, 1000, 2000, and 4000/L. During behavioural observations, which were carried out twice a week, foraging behaviour and activity of cod larvae were quantified. Larvae were sampled once a week and standard length and gut fullness were recorded. Larvae reared at concentrations of 1000 and 2000 prey/L swam significantly more but foraged (quantified by capture success) significantly less than the larvae reared at 4000 prey/L. Larvae reared at 4000 prey/L performed more orientations towards prey than larvae reared at all lower prey concentrations and the time spent per orientation increased from day 2 at all prey concentrations but declined as the larvae grew. However, this decline occurred earlier in larvae reared at 4000 prey/L than in larvae reared at other prey concentrations, and larvae reared at 4000 prey/L spent the shortest time per orientation at day 27 compared with day 34. Larvae reared at 4000 prey/L showed significantly higher success in capturing prey than larvae reared at all lower prey concentrations. After day 13 post hatch, larvae reared at 4000 prey/L were significantly greater in length than larvae reared at all other prey concentrations. Larvae reared at 0, 500, and 1000 prey/L did not survive beyond 11, 15, and 32 days, respectively, indicating that fewer than 2000 prey/L may not be adequate to keep cod larvae alive during intensive rearing. Our results suggest that the foraging behaviour of Atlantic cod larvae is influenced by prey concentration.

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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