scholarly journals Growth, survival, and development of Atlantic cod (Gadus morhua L.) weaned onto diets containing various sources of marine protein

2006 ◽  
Vol 63 (2) ◽  
pp. 320-325 ◽  
Author(s):  
I. Opstad ◽  
J. Suontama ◽  
E. Langmyhr ◽  
R.E. Olsen
Keyword(s):  
Gadus Morhua ◽  
Antarctic Krill ◽  
Atlantic Cod ◽  
Liver Index ◽  
First Feeding ◽  
Survival And Development ◽  
Wet Weight ◽  
The Mean ◽  
Alternative Sources ◽  
Marine Protein

Abstract We studied the effects of partial or complete substitution of fishmeal with alternative sources of marine protein (amphipod or krill meal) on growth, survival, liver index, and deformities of juvenile cod (Gadus morhua L.). The diets contained either 100% fishmeal or fishmeal that was replaced with 25%, 50%, or 100% amphipod meal or 50% or 100% Antarctic krill meal. Cod larvae were start-fed on rotifers and weaned directly to one of the six formulated feeds at a mean wet weight of 28 mg, 40 days post first-feeding. The mean weight of fish reared on different diets at the end of the experiment ranged from 0.92 to 2.52 g. The best growth was obtained by cod fed 100% fishmeal and 50% krill meal. There was a trend in the direction of slower growth with increasing levels of amphipod meal in the diets. Survival ranged from 87% to 79%, and there was a tendency for higher mortality with increasing content of amphipod meal. The liver index varied between 11.7% and 9.9%. The composition of the diets also had a significant influence on the occurrence of skeletal deformities. The highest proportion of deformities (16% of all fish) was in fish fed 100% amphipod meal, decreasing as the proportion of amphipod meal in the diets declined. A similar effect was not seen with Antarctic krill meal. The amphipod meal had a high content of ash, fluoride, cadmium, and mercury, which may have caused the deformities.

Seasonal and Geographic Variation in the Species Composition and Size of Prey Consumed by Grey Seals (Halichoerus grypus) on the Scotian Shelf

1993 ◽  
Vol 50 (8) ◽  
pp. 1768-1778 ◽  
Author(s):  
W. D. Bowen ◽  
J. W. Lawson ◽  
B. Beck
Keyword(s):  
Atlantic Cod ◽  
Halichoerus Grypus ◽  
Scotian Shelf ◽  
Sand Lance ◽  
Atlantic Mackerel ◽  
Relative Contribution ◽  
Wet Weight ◽  
The Mean ◽  
Silver Hake ◽  
Commercial Size

The grey seal (Halichoerus grypus) population on the Scotian Shelf has grown significantly over the past 20 yr, thus increasing the potential for competitive interactions between grey seals and fisheries. The relative contribution (percent wet weight) and size of prey eaten were estimated from otoliths and squid beaks recovered from 143 stomachs that contained food of the 528 collected from 1988 to 1990. Although 22 taxa were found, only four species (Atlantic herring, silver hake, Atlantic cod, and squid) accounted for 80% of the estimated weight of food eaten. The mean length of prey eaten ranged from 19 to 35 cm for six species. Only 17% of the cod and none of the pollock and squid eaten were of the length taken in commercial fisheries. However, about 80% of the silver hake and herring eaten were of commercial size. Offshore at Sable Island, northern sand lance, silver hake, and squid (in order of importance) accounted for 86.1% of the wet weight ingested by seals during summer; sand lance and cod accounted for 96.1% of prey eaten in winter. At inshore locations, herring, cod, and pollock made up 90% of the diet in summer; Atlantic mackerel, cod, squid, and herring made up 83% of the diet in winter.

scholarly journals Metabolic cost of feeding in Atlantic Cod (Gadus morhua) larvae using microcalorimetry

2006 ◽  
Vol 63 (2) ◽  
pp. 335-339 ◽  
Author(s):  
Artie McCollum ◽  
Jessica Geubtner ◽  
Ione Hunt von Herbing
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Metabolic Cost ◽  
Specific Dynamic Action ◽  
Total Heat ◽  
Heat Output ◽  
Larval Life ◽  
First Feeding ◽  
The Cost ◽  
Aerobic And Anaerobic

Abstract A microcalorimeter that measures total heat output (μW) was used to determine total metabolic rate (aerobic and anaerobic) and the cost of feeding (specific dynamic action, SDA) in larval Atlantic cod (Gadus morhua) from hatching to 4 weeks post-hatch at 10°C. Total heat output increased throughout development from 2.14 μW at first-feeding to 23.72 μW at 4 weeks post-hatch. SDA was determined by comparing the total heat output among unfed larvae and fed larvae simultaneously. Total heat output increased in the first 2 h after feeding with rotifers (Brachionus sp.) and Artemia, remained high for up to 10 h, was significantly higher in fed larvae than in unfed larvae, and ranged from 16.56 μW at first-feeding to 47.84 μW at 4 weeks post-hatch. The differences in total heat output between unfed and fed larvae were 14.42 μW and 24.12 μW, representing an increase in metabolic cost of feeding by a factor of 1.67 over the first 4 weeks of larval life. That the metabolic cost of feeding increased with development and remained elevated suggests that cod larvae allocate a large part of their energy budget to growth in order to meet the demands of their fast growth rates.

Some ectoparasitic trichodinids from Atlantic cod, Gadus morhua L., with a description of Trichodina cooperi n.sp.

1989 ◽  
Vol 67 (7) ◽  
pp. 1793-1800 ◽  
Author(s):  
S. L. Poynton ◽  
J. Lom
Keyword(s):  
Nova Scotia ◽  
Body Surface ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Geographic Range ◽  
The Body ◽  
Wild Fish ◽  
Eastern Canada ◽  
Mean Diameter ◽  
The Mean

Trichodina murmanica Polyanskiy, 1955 (= Trichodina domerguei subsp. saintjohnsi Lom and Laird, 1969) and Trichodina cooperi n.sp. were commonly encountered on skin and fins of Atlantic cod, Gadus morhua L., near Halifax, Nova Scotia, Canada. A third species of Trichodina, probably new, was recorded from the skin of one fish. This is believed to be the first report of the genus Trichodina from the body surface of gadoid fish from eastern Canada, and the known geographic range of T. murmanica is extended. Trichodina cooperi n.sp. has an adoral ciliary spiral of 370–380° and is relatively large, the mean diameter of the body is 110 μm, of the adhesive disc (with dark center), 95 μm, and of the denticulate ring, 59 μm. The denticulate ring consists of 24–29 denticles (usually 27), with 7–9 radial pins per denticle. Each denticle has a broad blade, a large central part, and a slightly curved thorn of moderate to broad width, with a central rib when mature. The thorn is approximately twice the length of the blade. The horseshoe-shaped macronucleus has a diameter of 80.0 μm and the micronucleus is in the +y position. Trichodina spp. infected 26% of 39 wild fish 20 to < 60 cm long. Most wild fish yielded less than five ciliates per 24 × 50 mm smear.

Effect of cultivated copepods (Acartia tonsa) in first-feeding of Atlantic cod (Gadus morhua) and ballan wrasse (Labrus bergylta) larvae

2015 ◽  
Vol 23 (1) ◽  
pp. 3-17 ◽  
Author(s):  
G. Øie ◽  
T. Galloway ◽  
M. Sørøy ◽  
M. Holmvaag Hansen ◽  
I.A. Norheim ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Acartia Tonsa ◽  
First Feeding ◽  
Labrus Bergylta

PACAP and nitric oxide inhibit contractions in the proximal intestine of the atlantic cod, Gadus morhua

2000 ◽  
Vol 203 (3) ◽  
pp. 575-583 ◽  
Author(s):  
C. Olsson ◽  
S. Holmgren
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Intestinal Motility ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Inhibitory Response ◽  
Nitric Oxide Donor ◽  
The Mean ◽  
Proximal Intestine ◽  
Spontaneous Contractions

The possible inhibitory roles of pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal polypeptide (VIP) and nitric oxide in the control of intestinal motility were investigated in the Atlantic cod, Gadus morhua. Circular and longitudinal smooth muscle preparations developed spontaneous contractions that were inhibited by atropine (10(−)(5)mol l(−)(1)). PACAP 27 and PACAP 38 (10(−)(7)mol l(−)(1)) reduced the amplitude of the contractions but did not usually affect the resting tension. In the circular preparations, the mean active force developed (above resting level; +/− s.e.m.) was reduced from 0. 62+/−0.18 mN to 0.03+/−0.03 mN (N=10) by PACAP 27 and from 0.53+/−0. 20 mN to 0.31+/−0.13 mN (N=7) by PACAP 38, while neither cod nor mammalian VIP (10(−)(10)-10(−)(6)mol l(−)(1)) had any effect. In the longitudinal preparations, PACAP 27 reduced the force developed from 1.58+/−0.22 mN to 0.44+/−0.25 mN (N=8) and PACAP 38 reduced it from 1.61+/−0.47 mN to 0.75+/−0.28 mN (N=5). The nitric oxide donor sodium nitroprusside (NaNP) almost abolished the contractions in the circular preparations, reducing the mean force developed from 0. 47+/−0.05 mN to 0.02+/−0.06 mN (10(−)(6)mol l(−)(1); N=9) and 0+/−0. 07 mN (10(−)(5)mol l(−)(1); N=8). In the longitudinal preparations, NaNP reduced the force developed from 2.03+/−0.36 mN to 0.33+/−0.22 mN (10(−)(6)mol l(−)(1); N=8) and 0.19+/−0.30 mN (10(−)(5)mol l(−)(1); N=8). The L-arginine analogue N(G)-nitro-L-arginine methyl ester (L-NAME; 3×10(−)(4)mol l(−)(1)) enhanced the contractions in both circular and longitudinal preparations, increasing the mean force developed from 0.51+/−0.12 mN to 0.94+/−0.21 mN (N=8) and from 1.49+/−0.36 mN to 3.34+/−0.67 mN (N=7), respectively. However, preincubation with L-NAME before a second addition of PACAP 27 (10(−)(7)mol l(−)(1)) did not affect the response to PACAP, neither did preincubation with the guanylate cyclase inhibitor 6-anilinoquinoline-5,8-quinone (LY83583; 10(−)(5)mol l(−)(1)), while the inhibitory response to NaNP (3×10(−)(7)mol l(−)(1)) was abolished by LY83583. The PACAP analogue PACAP 6–27 (3×10(−)(7)mol l(−)(1)) had no effect on the response to either NaNP (3×10(−)(7)mol l(−)(1)) or PACAP 27 (10(−)(8)mol l(−)(1)) in the circular preparations. These findings indicate the presence of both a cholinergic and a nitrergic tonus in the smooth muscle preparations of the cod. Although PACAP and NaNP both inhibit contractions, there is no evidence of any interactions between the two substances. In addition, NaNP, but not PACAP, probably acts via stimulating the production of cyclic GMP. In conclusion, both PACAP and nitric oxide may act as inhibitory transmitters, using distinct signalling pathways, in the control of intestinal motility in the Atlantic cod.

Muscle growth and development in Atlantic cod larvae (Gadus morhua L.), related to different somatic growth rates

1999 ◽  
Vol 202 (15) ◽  
pp. 2111-2120 ◽  
Author(s):  
T.F. Galloway ◽  
E. Kjorsvik ◽  
H. Kryvi
Keyword(s):  
Gadus Morhua ◽  
White Muscle ◽  
Atlantic Cod ◽  
Muscle Growth ◽  
Somatic Growth ◽  
Cross Sectional Area ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Cross Sectional ◽  
First Feeding

The present study describes the development of the axial musculature in first-feeding larvae of Atlantic cod (Gadus morhua L.) with different somatic growth rates achieved by using different nutritional conditions. Muscle growth was assessed by determining the number of muscle fibres (hyperplasia) and the growth of existing fibres (hypertrophy). Larvae were fed rotifers containing a high (1. 4; treatment 1) or low (0.2; treatment 2) ratio of docosahexaenoic acid to eicosapentaenoic acid from day 5 after hatching. From day 17, the larvae were fed Artemia nauplii with the same enrichment in both treatments. Treatment 1 gave the highest somatic growth rate and hence the highest dry mass at the end of the experiment, but no difference in larval standard length was found between treatments. In slow-growing larvae, higher priority was thus put into reaching a certain length than into increasing muscle mass. The largest fibres, which were present from hatching, increased in cross-sectional area during larval development, but no differences were found between treatments in the cross-sectional area of individual fibres or the total cross-sectional area of these fibres at the end of the experiment. The first white recruitment fibres were observed at the dorsal and ventral apices of the myotome at approximately the onset of first feeding (larval length 4.5 mm). In larvae 8.5 mm long, the total cross-sectional area of white muscle fibres in the treatment 2 group was 75 % of that in the treatment 1 group. The highest somatic growth rate was associated with an increased contribution of hyperplasia to axial white muscle growth. In the faster-growing larval group, the relative contribution of hyperplasia to the total white muscle cross-sectional area was 50 %, whereas it was 41 % in the slower-growing larval group. The subsequent growth potential may thus be negatively affected by inadequate larval feeding.

scholarly journals Quality of Nephrops as food for Atlantic cod (Gadus morhua L.) with possible implications for fisheries management

2004 ◽  
Vol 61 (6) ◽  
pp. 983-991 ◽  
Author(s):  
Björn Björnsson ◽  
Maria Álvaro Dongala Dombaxe
Keyword(s):  
Growth Rate ◽  
Gadus Morhua ◽  
Specific Growth ◽  
Condition Factor ◽  
Atlantic Cod ◽  
Gonadosomatic Index ◽  
Conversion Ratio ◽  
Food Conversion ◽  
The Mean

Abstract Nephrops was found to be of low quality as food for cod. In a laboratory experiment the mean specific growth rate of 1 kg cod was 0.184 and 0.415% d−1 when fed to satiation on Nephrops and capelin, respectively. This large difference in growth rate resulted not only from less intake of Nephrops (1.19 kg cod−1) than capelin (1.55 kg cod−1) but also because more Nephrops (4.6 kg) than capelin (2.2 kg) were required to produce each kilogramme of cod. Higher food conversion ratio was consistent with lower fat content of Nephrops (1.3%) than capelin (9.2%) but the exoskeleton also reduced the digestion rate of Nephrops. In the groups where Nephrops and capelin of equal mean weight were offered simultaneously, 40% of the diet consisted of Nephrops during the first week and 10% during the final seven weeks of the experiment. At the end of the experiment, condition factor, liver index, and gonadosomatic index were significantly lower for cod fed on Nephrops (0.967, 5.7, 7.1, respectively) than for those fed on capelin (1.086, 15.8, 11.2, respectively). These results suggests that predation by cod on Nephrops might be reduced by regular release of capelin or other similar food in the distributional areas of Nephrops.

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.

scholarly journals Salt-Cured Atlantic Cod Skin: A Sustainable Source of Acid-Soluble Type I Collagen

2021 ◽  
Author(s):  
Ezequiel Coscueta ◽  
María Emilia Brassesco ◽  
Manuela Pintado
Keyword(s):  
Gadus Morhua ◽  
Type I Collagen ◽  
Atlantic Cod ◽  
Electrophoretic Pattern ◽  
Helical Structure ◽  
Extraction Yield ◽  
Type I ◽  
Acid Soluble Collagen ◽  
Typical Type ◽  
Alternative Sources

Collagen is the most abundant protein in the animal kingdom. Industrial collagen is mainly bovine and porcine origin. However, due to religious beliefs, allergic issues, and infectious diseases, alternative sources of collagen as marine are gaining increasing interest. In this work, the acid-soluble collagen (ASC) were extracted from salt-cured Atlantic cod (Gadus morhua) skin and characterized. The extraction yield was about 2.0%, equivalent to the extraction yield reported for other fish skins. The electrophoretic pattern showed the typical type I structure (&alpha;, &beta; and &gamma; chains). UV-VIS and FTIR absorbance spectra suggested a very pure ASC with an intact triple helical structure. The integrity and the adequate porosity required for different applications were then confirmed by electron micrograph. Our findings allow us to say that, for the first time, we extracted acid-soluble type I collagen from salt-cured Atlantic cod skin, with characteristics suitable for application in various fields, such as biomedical.

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