Effects of turbidity on the reactive distance, search time, and foraging success of juvenile Atlantic cod (Gadus morhua)

2005 ◽  
Vol 62 (9) ◽  
pp. 1978-1984 ◽  
Author(s):  
Justin J Meager ◽  
Turid Solbakken ◽  
Anne C Utne-Palm ◽  
Tina Oen
Keyword(s):  
Visual Cues ◽  
Gadus Morhua ◽  
Chemical Cues ◽  
Atlantic Cod ◽  
Search Time ◽  
Turbid Water ◽  
Reactive Distance ◽  
Negative Effect ◽  
Dark Conditions ◽  
Predation Rates

We investigated the effects of turbidity on the foraging behaviour of juvenile Atlantic cod (Gadus morhua) on mysid prey (Praunus neglectus) in the laboratory. The influence of turbidity on vision and chemoreception was examined by measuring reactive distances and search times to visual, chemical, and visual–chemical prey cues over turbidity levels ranging from 0.4 to 17·m–1 (beam attenuation·m–1). We also compared foraging rates of juvenile cod on mysids in highly turbid water and clear water under well lit and totally dark conditions. Juvenile cod using chemical cues were able to locate mysids from significantly longer distances than when only visual cues were available. Turbidity did not affect reactive distance to chemical cues, and had only a weak negative effect on reactive distance to visual and visual–chemical cues. Search time was variable, but tended to increase with turbidity. Turbidity did not affect predation rates on free-ranging mysids, but predation rates were significantly lower in dark conditions than in well lit conditions. We suggest that juvenile cod use chemoreception in conjunction with vision (at close ranges) to locate prey in highly turbid water.

Using acoustic telemetry to observe the effects of a groundfish predator (Atlantic cod, Gadus morhua) on movement of the American lobster (Homarus americanus)

2013 ◽  
Vol 70 (11) ◽  
pp. 1625-1634 ◽  
Author(s):  
Marissa D. McMahan ◽  
Damian C. Brady ◽  
Diane F. Cowan ◽  
Jonathan H. Grabowski ◽  
Graham D. Sherwood
Keyword(s):  
Home Range ◽  
Behavioral Response ◽  
Acoustic Telemetry ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Homarus Americanus ◽  
American Lobster ◽  
Habitat Area ◽  
Predation Rates

American lobster (Homarus americanus) landings have more than quadrupled in the last two decades (1990–2010), coinciding with the collapse of Gulf of Maine groundfish fisheries such as Atlantic cod (Gadus morhua). Recently there has been speculation that the release of lobster from predatory control may have resulted in both lower predation rates and increased foraging areas. We used fine-scale acoustic telemetry within a 200 m × 250 m field enclosure to test the hypothesis that cod induce lobsters to decrease movement and seek refuge. We found a large amount of variation in the behavioral response of individual lobsters to predators; however, the addition of cod into the enclosure reduced maximum daily home range area and significantly reduced the distance traveled from shelter habitat area for all individuals. When predators were removed from the enclosure, lobsters responded by increasing home range area and significantly increasing the distance traveled from shelter habitat area. These results represent the first experimental evidence for American lobster range contraction and subsequent expansion in the presence and absence of cod, respectively.

Predator Stomachs as Sampling Tools for Prey Distribution: Atlantic Cod (Gadus morhua) and Capelin (Mallotus villosus)

1993 ◽  
Vol 50 (7) ◽  
pp. 1541-1547 ◽  
Author(s):  
Lenore Fahrig ◽  
George R. Lilly ◽  
Daniel S. Miller
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Mallotus Villosus ◽  
Predator Prey ◽  
Prey Distribution ◽  
Capelin Mallotus Villosus ◽  
Negative Effect ◽  
Predator Abundance ◽  
Bottom Depth

We demonstrate a direct relationship between the amount of prey (capelin, Mallotus villosus) in its predators' stomachs (Atlantic cod, Gadus morhua) and the biomass of the prey in the same localities. The relationship at a local scale implies that predator stomach contents can be used to estimate prey distribution. There is no evidence for either (1) a negative effect of local predator abundance on stomach contents (expected if local prey depletion and/or feeding interference occurs when predator density is high) or (2) a negative effect of the amount of other food in cod stomachs on the amount of capelin in the stomachs (expected if prey switching occurs). There is a negative effect of bottom depth on amount of capelin in cod stomachs as expected, since capelin are pelagic and cod are primarily bottom-dwelling, resulting in less vertical overlap between the species in deep water. This type of analysis may be useful in other predator–prey systems. Simultaneous stomach samples and independent biomass estimates of the prey are required, but once the model is built, it permits estimation of prey distribution in places and times when no direct survey of the prey can be done.

Effects of temperature on life history set the sensitivity to fishing in Atlantic cod Gadus morhua

2014 ◽  
Vol 514 ◽  
pp. 217-229 ◽  
Author(s):  
HY Wang ◽  
LW Botsford ◽  
JW White ◽  
MJ Fogarty ◽  
F Juanes ◽  
...  
Keyword(s):  
Life History ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Effects Of Temperature

Responses of Atlantic cod Gadus morhua head kidney leukocytes to phytase produced by gastrointestinal-derived bacteria

2009 ◽  
Vol 36 (4) ◽  
pp. 883-891 ◽  
Author(s):  
Carlo C. Lazado ◽  
Christopher Marlowe A. Caipang ◽  
Sanchala Gallage ◽  
Monica F. Brinchmann ◽  
Viswanath Kiron
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Head Kidney

Some recent data on sperm morphology and motility kinetics in Atlantic cod (Gadus morhua L.)

2021 ◽  
Author(s):  
Sayyed Mohammad Hadi Alavi ◽  
Azadeh Hatef ◽  
Ian A.E. Butts ◽  
Olga Bondarenko ◽  
Jacky Cosson ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Sperm Morphology ◽  
Atlantic Cod

Natural mortality from poor condition in Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Impact ◽  
Fish Muscle ◽  
Early Summer ◽  
Wild Fish ◽  
Natural Mortality ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Poor Condition

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.

scholarly journals Gastrointestinal microbial community changes in Atlantic cod (Gadus morhua) exposed to crude oil

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Andrea Bagi ◽  
Even Sannes Riiser ◽  
Hilde Steine Molland ◽  
Bastiaan Star ◽  
Thomas H. A. Haverkamp ◽  
...  
Keyword(s):  
Microbial Community ◽  
Crude Oil ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Community Changes

scholarly journals Development of Atlantic cod (Gadus morhua) exposed to produced water during early life stages: Effects on embryos, larvae, and juvenile fish

2010 ◽  
Vol 70 (5) ◽  
pp. 383-394 ◽  
Author(s):  
Sonnich Meier ◽  
H. Craig Morton ◽  
Gunnar Nyhammer ◽  
Bjørn Einar Grøsvik ◽  
Valeri Makhotin ◽  
...  
Keyword(s):  
Early Life ◽  
Gadus Morhua ◽  
Produced Water ◽  
Atlantic Cod ◽  
Juvenile Fish ◽  
Life Stages ◽  
Early Life Stages

Induction of triploidy in Atlantic cod (Gadus morhua L.) by thermal shocks

Aquaculture ◽  
2007 ◽  
Vol 272 ◽  
pp. S276
Author(s):  
A. Kettunen ◽  
G. Kauric ◽  
S. Peruzzi
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Thermal Shocks
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