Assessing the impact of buffer towing on the quality of Northeast Atlantic cod (Gadus morhua) caught with a bottom trawl

Variations in the occurrence of Oikopleura spp. were strongly linked to the wind field and ensuing water temperatures in an inshore region of eastern Newfoundland during June–August of 1979 and 1981–83. Oikopleura foul inshore fishing gear with their discarded houses ("slub") and fluctuate in abundance from day to day as a function of wind-driven upwelling. Densities of Oikopleura in cold upwelling water during four years ranged between 20 and 800/m3. Oikopleura densities < 1/m3 occurred when upwelling ceased and warmer water occupied the inshore region. A simple model incorporating a daily averaged wind vector, Julian day, and growing degree-day explained 62% of the daily variation in Oikopleura abundance in 1979. The model yielded density estimates that were significantly (p < 0.05) correlated with observed densities in each of the other three years. We provide evidence that net fouling by Oikopleura in the inshore and maximum Atlantic cod (Gadus morhua) catch is coincident and suggest that an annual hindcast index of slub intensity may help determine the impact of slub conditions on the inshore fishery.

Download Full-text

Simulated trawling: Exhaustive swimming followed by extreme crowding as contributing reasons to variable fillet quality in trawl-caught Atlantic cod (Gadus morhua)

10.1101/372581 ◽

2018 ◽

Author(s):

Ragnhild Aven Svalheim ◽

Øyvind Aas-Hansen ◽

Karsten Heia ◽

Anders Karlsson-Drangsholt ◽

Stein Harris Olsen ◽

...

Keyword(s):

Plasma Cortisol ◽

Gadus Morhua ◽

Atlantic Cod ◽

Metabolic Stress ◽

Small Degree ◽

Negative Effects ◽

Muscle Ph ◽

Fillet Quality ◽

Capture Stress

AbstractTrawl-caught Atlantic cod (Gadus morhua) often yield highly variable fillet quality that may be related to capture stress. To investigate mechanisms involved in causing variable quality, commercial-sized (3.5±0.9 kg) Atlantic cod were swum to exhaustion in a large swim tunnel and subsequently exposed to extreme crowding (736±50 kg m-3) for 0, 1 or 3 hours in an experimental cod-end. The fish were then recuperated for 0, 3 or 6 hours in a net pen prior to slaughter to assess the possibility to reverse the reduced fillet quality. We found that exhaustive swimming and crowding were associated with increased metabolic stress, as indicated by increased plasma cortisol, blood lactate and blood haematocrit levels, accompanied by reduced quality of the fillets due to increased visual redness and lower initial muscle pH. The observed negative effects of exhaustive swimming and crowding were only to a small degree reversed within 6 hours of recuperation. The results from this study suggest that exhaustive swimming followed by extreme crowding can reduce fillet quality and contribute to the variable fillet quality seen in trawl-caught Atlantic cod. Recuperation for more than six hours may be required to reverse these effects.

Download Full-text

Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence

ICES Journal of Marine Science ◽

10.1006/jmsc.1999.0516 ◽

2000 ◽

Vol 57 (1) ◽

pp. 56-68 ◽

Cited By ~ 11

Author(s):

D Swain

Keyword(s):

Water Temperature ◽

Gadus Morhua ◽

Atlantic Cod ◽

Bottom Trawl ◽

Trawl Survey ◽

Bottom Trawl Survey ◽

Effect Of Water

Download Full-text

Inhibitory effects of Atlantic cod (Gadus morhua) peptides on RANKL-induced osteoclastogenesis in vitro and osteoporosis in ovariectomized mice

Food & Function ◽

10.1039/d1fo03696c ◽

2022 ◽

Author(s):

Meilian Yang ◽

Di Wu ◽

Shuzhen Cheng ◽

Yu Dong ◽

Chao Wu ◽

...

Keyword(s):

Nutritional Value ◽

Gadus Morhua ◽

Atlantic Cod ◽

Economic Value ◽

Underlying Mechanism ◽

Inhibitory Effects ◽

Ovariectomized Mice ◽

The World ◽

The Impact

Atlantic cod (Gadus morhua) is one of the most important fishes in the world with high nutritional value and economic value. However, the impact and underlying mechanism of the G....

Download Full-text

Effect of Antarctic krillmeal on quality of farmed Atlantic cod (Gadus morhua L.)

Aquaculture Research ◽

10.1111/j.1365-2109.2006.01615.x ◽

2006 ◽

Vol 37 (16) ◽

pp. 1676-1684 ◽

Cited By ~ 13

Author(s):

Ørjan Karlsen ◽

Jorma Suontama ◽

Rolf Erik Olsen

Keyword(s):

Gadus Morhua ◽

Atlantic Cod

Download Full-text

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

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.06.017 ◽

2004 ◽

Vol 61 (6) ◽

pp. 983-991 ◽

Cited By ~ 5

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.

Download Full-text