Nonrandom mating in a broadcast spawner: mate size influences reproductive success in Atlantic cod (Gadus morhua)

2007 ◽  
Vol 64 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Sherrylynn Rowe ◽  
Jeffrey A Hutchings ◽  
Jon Egil Skjæraasen
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Consequences ◽  
Nonrandom Mating ◽  
Individual Fitness ◽  
Mean And Variance ◽  
The Mean ◽  
Natural Breeding

We tested the hypothesis that reproductive success in Atlantic cod (Gadus morhua) is random with respect to similarity in body size between mates. Immediately prior to their natural breeding periods, groups of 52–93 cod from three Northwest Atlantic populations were transported to a large (15 m diameter, 4 m deep) tank where they spawned undisturbed at densities similar to those in nature. Based on microsatellite DNA-parentage assignment of 8913 offspring from four spawning groups, females and males achieved their highest reproductive success when breeding with mates that were larger than themselves. Our observations are consistent with the hypothesis that some form of intrasexual competition or mate choice is a constituent of the mating system of this species and that this can have an important influence on individual fitness. Our results further suggest that reductions in the mean and variance in body size of commercially exploited marine fishes concomitant with size-selective harvesting may have greater negative consequences for population recovery than previously thought.

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.

Male reproductive success and body size in Atlantic cod Gadus morhua L.

2001 ◽  
Vol 138 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
Not Available Not Available ◽  
Not Available Not Available ◽  
Not Available Not Available
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Male Reproductive Success

Nearshore settlement and localized populations of age 0 Atlantic cod (Gadus morhua) in shallow coastal waters of Newfoundland

1998 ◽  
Vol 55 (6) ◽  
pp. 1317-1327 ◽  
Author(s):  
Scott M Grant ◽  
Joseph A Brown
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Indirect Evidence ◽  
Suitable Habitat ◽  
Site Variation ◽  
Mean And Variance ◽  
Eelgrass Habitat ◽  
The Mean ◽  
Catch Rates ◽  
Density Dependent Habitat Selection

Mark-recapture experiments and seasonal sampling were carried out to examine the nearshore movements, abundance, and behaviour patterns of age 0 Atlantic cod (Gadus morhua) in eelgrass (Zostera marina) and no-eelgrass habitat in Trinity Bay, Newfoundland, during 1994 and 1995. Cod remained localized, not moving further than a few hundred metres in eelgrass and no-eelgrass habitats for several weeks after settling from a pelagic habit, and may remain localized during their first winter. Observations from this study of bulk movements of marked and unmarked cod, high within-site variation in catch rates during the day, and significant day-night differences in the mean and variance of catch data, combined with results from related studies, provide indirect evidence that age 0 cod shoal during the day and disperse at night within the study area. Behaviour patterns exhibited by age 0 cod (restricted nearshore movements, diurnal shoaling, and preference for structurally complex habitat) are mechanisms for predator avoidance, suggesting that predation risk is high in coastal Newfoundland. A significant increase in abundance of age 0 cod in less suitable habitat (no-eelgrass cover) when settlement strength was high is consistent with the hypothesis of density-dependent habitat selection.

Temporal variability in offspring quality and individual reproductive output in a broadcast-spawning marine fish

2017 ◽  
Vol 75 (4) ◽  
pp. 1353-1361 ◽  
Author(s):  
Nancy E Roney ◽  
Rebekah A Oomen ◽  
Halvor Knutsen ◽  
Esben M Olsen ◽  
Jeffrey A Hutchings
Keyword(s):  
Body Size ◽  
Temporal Variability ◽  
Gadus Morhua ◽  
Reproductive Output ◽  
Atlantic Cod ◽  
Offspring Quality ◽  
Spawning Period ◽  
Broadcast Spawning ◽  
Batch Number ◽  
Individual Fitness

Abstract The protracted spawning period of broadcast-spawning marine fishes has potential to generate considerable variability in metrics of individual reproductive output. We undertook a temporally detailed genetic study of larvae produced by Atlantic cod (Gadus morhua) from two spatially proximate populations spawning under controlled semi-natural conditions over 94 days. Based on daily samples of larvae (n = 4489 in total), we document fine-scaled temporal changes in, and correlates of, offspring phenotype and reproductive output (egg batches produced or fertilized). Larval length and standardized yolk-sac volume declined 11 and 49% over the spawning period, respectively. The adaptive significance of these trends is unclear. Longer, heavier females produced longer, better-provisioned larvae. Body size affected the number of egg batches to which an individual contributed genetically but not spawning duration. Males contributed gametes to a greater number of egg batches (19.5 vs. 9.2), and spawned over a longer period of time (48.9 vs. 30.8 days), than females. After accounting for body size and condition, egg batch number and spawning duration differed between adjacent populations separated by < 10 km. Our work highlights the need to understand the environmental and adaptive causes of temporal variability in offspring quality and its consequences to individual fitness and per capita population growth in batch-spawning fishes.

scholarly journals The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua

2008 ◽  
Vol 65 (7) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Bang ◽  
P. Grønkjær ◽  
B. Lorenzen
Keyword(s):  
Trace Elements ◽  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
The Body ◽  
Small Fish ◽  
Female Size ◽  
Large Fish ◽  
Size Category ◽  
Linear Discriminant

Abstract Bang, A., Grønkjær, P., and Lorenzen, B. 2008. The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua. – ICES Journal of Marine Science, 65: 1191–1197. Trace metals in the ovaries of fish are transferred from the female via the yolk to the offspring, which makes the early life stages susceptible to deleterious effects of potentially toxic elements contained in the ovaries. Here, the concentrations of 13 elements from the ovaries of 133 ripe female North Sea cod Gadus morhua weighing 0.2–18 kg were correlated with female size, accounting for differences in maturity and condition. Most elements were negatively correlated with the size variables weight, length and, especially, ovarian dry weight. Further, they were negatively correlated with maturity and condition. Many of the trace elements showed true size-dependence, but the correlations were generally weak. A linear discriminant analysis separated “small” and “large” fish at a length of 85 cm based on concentrations of Co, Mn, Se, and Zn, and correctly assigned 78 of 102 small fish and 23 of 31 large fish to their respective size category. This corresponds to an overall classification success of 75.9%. The results suggest that embryos and early larvae from small females are exposed to higher levels of potentially harmful metals. If the differences in trace element concentration influence survival success, this will add to the negative effects of size distribution truncation and declines in size-at-maturity experienced by many populations of cod.

Shifting reproductive success in a shoal of Atlantic Cod, Gadus morhua L.

2010 ◽  
Vol 88 (4) ◽  
pp. 311-318 ◽  
Author(s):  
Jon Egil Skjæraasen ◽  
Jeffrey A. Hutchings
Keyword(s):  
Reproductive Success ◽  
Gadus Morhua ◽  
Atlantic Cod

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.

Comparative Survival and Growth of Two Strains of Atlantic Cod (Gadus morhua) through the Early Life Stages in a Marine Pond

1994 ◽  
Vol 51 (5) ◽  
pp. 1012-1023 ◽  
Author(s):  
Geir Blom ◽  
Terje Svåsand ◽  
Knut E. Jørstad ◽  
Håkon Otterå ◽  
Ole I. Paulsen ◽  
...  
Keyword(s):  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Larval Mortality ◽  
Food Limitation ◽  
Juvenile Stage ◽  
Average Growth ◽  
Juvenile Mortality ◽  
Early Juvenile Stage ◽  
Survival And Growth

Survival and growth of two strains of Atlantic cod (Gadus morhua) were compared through the larval and juvenile stages in a marine pond in western Norway in 1990 and 1991. Strain A was homozygous for the genetic marker allele GPI-1*30 at the glucose phosphate isomerase (GPI) locus expressed in white muscle, and Strain B possessed other GPI-1* genotypes, in 1990 the frequency of Strain B increased significantly from the larval to the juvenile stage; however, in 1991 the frequency of Strain A increased slightly but not significantly from the larval to the juvenile phase. Larval mortality did not differ significantly between strains any year, but juvenile mortality was significantly lower in Strain B in 1990 and Strain A in 1991. Average growth rates in length estimated from regressions were not significantly different between strains during the larval and juvenile period any year, but initial length was significantly larger in Strain B in 1990 and Strain A in 1991. Our results indicated that food limitation during the early juvenile stage induced differential size-selective mortality among the strains due to small differences in body size and actual age between strains. Body size did not become important for survival until the food-limited regime had occurred.

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.

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.

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