Selection of candidate probionts by two different screening strategies from Atlantic cod (Gadus morhua L.) larvae

Abstract The aquaculture industry in Norway is now focused on developing economically viable farming based on the Atlantic cod, Gadus morhua. Extensive research has been carried out on this species for the past two decades, much of it in connection with stock enhancement. Until now, most of the intensive cage culture has been based on wild broodstock. However, a future cod aquaculture industry must be based on a domesticated broodstock, and the initial selection of wild cod becomes an important issue. Genetic differentiation between coastal cod populations in Norway has been reported, and it is of interest to evaluate offspring from some of these populations under farmed conditions. Live mature cod were collected at four selected spawning sites along the Norwegian coast (Porsangerfjord, Tysfjord, Herøy/Helgeland, and Øygarden). The fish were transported to Parisvatnet, a cod aquaculture facility west of Bergen, where they were kept in net pens. Individual tagging and extensive sampling (blood, white muscle, and fin clips) for genetic characterization were carried out. Each potential broodstock fish was genotyped at the haemoglobin and pantophysin I loci in addition to five allozyme (LDH-3∗, GPD∗, IDH-2∗, PGM∗, PGI-1∗) and ten microsatellite loci (Gmo2, Gmo3, Gmo8, Gmo19, Gmo34, Gmo35, Gmo36, Gmo37, Gmo132, Tch11). Comparison of allele frequencies revealed significant genetic differences among some of the coastal cod samples, and offspring performance of the broodstock is now being compared under farmed conditions. The overall test revealed significant genetic differences among the coastal broodstocks, with the HbI, PanI and the microsatellite Gmo132 loci being most informative.

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Seasonal variation in the habitat associations of Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) from the southern Gulf of St. Lawrence

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-122 ◽

1998 ◽

Vol 55 (12) ◽

pp. 2548-2561 ◽

Cited By ~ 36

Author(s):

D P Swain ◽

G A Chouinard ◽

R Morin ◽

K F Drinkwater

Keyword(s):

Seasonal Variation ◽

Habitat Selection ◽

Gadus Morhua ◽

Atlantic Cod ◽

Statistical Significance ◽

Habitat Associations ◽

Practical Implications ◽

Hippoglossoides Platessoides ◽

Trawl Surveys ◽

Selection Of

We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) between the summer feeding season on the Magdalen Shallows and the overwintering period in the Cabot Strait. Data were from bottom trawl surveys conducted in September 1993, 1994, and 1995 and January 1994, 1995, and 1996. Both species occupied much deeper, warmer water in winter than in summer. The effect of cod age on temperature distribution reversed between the two seasons, with younger cod occupying warmer water than older cod in summer and colder water in winter. Selection of both depth and temperature by cod tended to be more significant in September than in January. The reduced statistical significance of habitat selection by cod in winter was associated with a more aggregated distribution in this season. The contrast between seasons in habitat associations was particularly strong for plaice. The median habitats occupied by plaice were 58-67 m and -0.1 to 0.3°C in September and 374-426 m and 5.2-5.4°C in January. Habitat selection by plaice was significant in both seasons, but significance tended to be greater in January. Degree of aggregation in plaice distribution was similar between the two seasons. Female plaice occupied significantly warmer water than males in September but not in January. The ecological and practical implications of this striking seasonal variation in habitat associations are discussed.

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Selection of reference genes for qRT-PCR examination of wild populations of Atlantic cod Gadus morhua

BMC Research Notes ◽

10.1186/1756-0500-1-47 ◽

2008 ◽

Vol 1 (1) ◽

pp. 47 ◽

Cited By ~ 67

Author(s):

Pål A Olsvik ◽

Liv Søfteland ◽

Kai K Lie

Keyword(s):

Reference Genes ◽

Gadus Morhua ◽

Atlantic Cod ◽

Wild Populations ◽

Qrt Pcr ◽

Selection Of

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Erratum to: Selection of reference genes for qRT-PCR examination of wild populations of Atlantic cod Gadus morhua

BMC Research Notes ◽

10.1186/1756-0500-4-456 ◽

2011 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Pal A Olsvik ◽

Liv Softeland ◽

Kai K Lie

Keyword(s):

Reference Genes ◽

Gadus Morhua ◽

Atlantic Cod ◽

Wild Populations ◽

Qrt Pcr ◽

Selection Of

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Density-independent and -dependent habitat selection of Atlantic cod (Gadus morhua) based on geostatistical aggregation curves in the northern Gulf of St Lawrence

ICES Journal of Marine Science ◽

10.1093/icesjms/fsq108 ◽

2010 ◽

Vol 67 (8) ◽

pp. 1676-1686 ◽

Cited By ~ 18

Author(s):

Hacène Tamdrari ◽

Martin Castonguay ◽

Jean-Claude Brêthes ◽

Daniel Duplisea

Keyword(s):

Habitat Selection ◽

Gadus Morhua ◽

Atlantic Cod ◽

Local Density ◽

Abiotic Factors ◽

Age Groups ◽

Spatial Dynamics ◽

Entire Area ◽

Dynamics Models ◽

Selection Of

Abstract Tamdrari, H., Castonguay, M., Brêthes, J-C., and Duplisea, D. 2010. Density-independent and -dependent habitat selection of Atlantic cod (Gadus morhua) based on geostatistical aggregation curves in the northern Gulf of St Lawrence. – ICES Journal of Marine Science, 67: 1676–1686. Relationships were sought between local density and population abundance of Atlantic cod (Gadus morhua) in the northern Gulf of St Lawrence (Canada) over its entire area (4RS) and also within a subarea (4R) where the stock has concentrated since it collapsed during the early 1990s. Relationships were analysed using geostatistical aggregation curves computed within the two areas between years of contrasting abundance levels. The curves were interpreted in terms of four conceptual models of spatial dynamics: models D1 and D2, forced mainly by environmental heterogeneity, and models D3 and D4, in which individual behaviour is influenced by local density. Over the entire area, the cod population follows the D2 model for all years and age groups, and it is influenced by abiotic factors. Within the subarea, all four models applied, and the density-dependent basin model (D4) dominated from 2006 to 2008. The year 2006 seems to be pivotal because it coincides with the expansion of the cod population into its former area in the western Gulf (4S).

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A comparison of size selection of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) by bottom longlines and otter trawls

Fisheries Research ◽

10.1016/s0165-7836(01)00336-8 ◽

2002 ◽

Vol 57 (1) ◽

pp. 63-73 ◽

Cited By ~ 20

Author(s):

R.G. Halliday

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Melanogrammus Aeglefinus ◽

Size Selection ◽

Haddock Melanogrammus Aeglefinus ◽

Selection Of

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Back-calculation of previous fish size using individually tagged and marked Atlantic cod (Gadus morhua)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f08-157 ◽

2008 ◽

Vol 65 (11) ◽

pp. 2496-2508 ◽

Cited By ~ 16

Author(s):

L. Li ◽

H. Høie ◽

A. J. Geffen ◽

E. Heegaard ◽

J. Skadal ◽

...

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Time Interval ◽

Fish Length ◽

Food Regimes ◽

Back Calculation ◽

Width Measurements ◽

Nonlinear Scale ◽

Marking Time ◽

Selection Of

The performance of five back-calculation (B-C) models was tested with individually tagged and multiple alizarin-marked Atlantic cod ( Gadus morhua ) reared at seasonally varying water temperature and food regimes over a 10-month period. The otoliths were transversely sectioned and the otolith growth between marks was measured along the dorsal, distal, and ventral radii and across the otolith width. Observed fish lengths at each marking time were compared with back-calculated lengths using linear and nonlinear scale and body proportional hypotheses (SPH and BPH) and biological intercept (BI) models. Measurements along the dorsal and distal radius with SPH and BI provided more accurate fish length estimates but with lower precision, whereas measurements of the ventral radius consistently produced greater overestimations by any model. Otolith width measurements produced moderately overestimated fish length estimates but with the highest precision and were significantly affected by temperature in all models. Certain combinations of model and otolith dimension were more sensitive to the length of the back-calculation time interval, whereas varying feeding regime induced temporary biases only. The selection of B-C model and otolith dimension thus depends not only on the environmental conditions that the fish experience, but also on the requirements of the application for which the B-C is used.

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Comparison of growth rate among different protein genotypes in Atlantic cod, Gadus morhua, under farmed conditions

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.11.005 ◽

2006 ◽

Vol 63 (2) ◽

pp. 235-245 ◽

Cited By ~ 7

Author(s):

K.E. Jørstad ◽

Ø. Karlsen ◽

T. Svåsand ◽

H. Otterå

Keyword(s):

Growth Rate ◽

Gadus Morhua ◽

White Muscle ◽

Specific Growth ◽

Atlantic Cod ◽

The Past ◽

Aquaculture Industry ◽

A New Species ◽

Growth Experiments ◽

Selection Of

Abstract A major aim of the aquaculture industry in Norway is to develop sustainable farming of Atlantic cod, Gadus morhua L. A great deal of research, including farming trials and stock enhancement, has been performed on this species in Norway during the past two decades. The success of domestication of a new species depends on the genetic variability of the wild broodstock and the selection of appropriate genotypes for the farming environment. Growth experiments under farmed conditions, including genetic analyses, were started as early as 1983 after the breakthrough of cod juvenile production in mesocosm systems. At later stages (1988 and 1992 year classes), more detailed studies were conducted under farmed conditions. Based on individual tagging and genotyping (blood and white muscle biopsy sampling), estimates of growth performance (specific growth rate, SGR) of the various genotypes within six polymorphic protein loci were obtained. In general, the SGR in the two experiments varied through the year as a function of temperature and body size. In the 1988 year-class experiment, only a few statistically significant differences (ANOVA) were detected among genotypes, measured as mean weight and SGR. The 1992 year-class experiment included two different cod stocks, Northeast Arctic (NE) and Norwegian coastal (NC) cod, which were reared for about two years in the same net pen. Further, during this experiment, only a few genotypes exhibited significantly different growth within the NE group. No consistency was found in the variation with regard to protein loci investigated, growth periods studied, and relationship with temperature variation.

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