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.

Larval Anisakis simplex (Nematoda: Ascaridoidea) Infection in the Musculature of Atlantic Cod, Gadus morhua, from Newfoundland and Labrador

1992 ◽  
Vol 49 (12) ◽  
pp. 2635-2647 ◽  
Author(s):  
John Brattey ◽  
Claude A. Bishop
Keyword(s):  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Body Cavity ◽  
The Body ◽  
Anisakis Simplex ◽  
South Coast ◽  
The South ◽  
Eastern Canada ◽  
Examination Method

Larvae of Anisakis simplex were found in the flesh of Atlantic cod, Gadus morhua, collected in 21 regions around Newfoundland and Labrador during 1985–87. Prevalence and abundance increased with cod size and varied geographically; cod off Labrador had the fewest larvae whereas those from the south coast of Newfoundland were the most heavily infected. Most larvae (~95%) occurred in flesh surrounding the body cavity (napes), with a significantly higher percentage of the nematodes (~58%) in the flesh on the left side. In 505 cod in which all tissues were examined, 85.6, 10.8, and 3.5% of the A. simplex resided in the body cavity and viscera, napes, and fillets, respectively. Cod surveyed tended to have more A. simplex in the musculature than those from other areas off eastern Canada, but are lightly infected compared with most other Atlantic cod stocks. The examination method (candling combined with slicing) recovered, on average, 42% of the A. simplex present in the flesh; consequently, infection statistics reported here are underestimates. Numbers of A. simplex in cod off Labrador and eastern Newfoundland are similar to those observed during 1947–53, but the abundance of A. simplex appears to have increased among cod from NAFO Subdivision 3Pn.

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.

Automated monitoring of a large-scale cod (Gadus morhua) migration in the open sea

2002 ◽  
Vol 59 (12) ◽  
pp. 1845-1850 ◽  
Author(s):  
Luc A Comeau ◽  
Steven E Campana ◽  
Martin Castonguay
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Seasonal Migration ◽  
Migration Routes ◽  
Eastern Canada ◽  
Migration Patterns ◽  
Migration Timing ◽  
Open Sea ◽  
And Migration

The migration patterns of marine fishes are poorly known, in part owing to the technical limitations associated with tracking the movements of animals in deep water. Here we document a large-scale, directed, migration of Atlantic cod (Gadus morhua) off eastern Canada. Our approach was based on the acoustic tagging of 126 fish and the deployment of 69 subsurface receivers, stretching over a 160-km distance along the edge of the Laurentian Channel. After 1 year of automated recording, we found that 65% of the fish migrated out of coastal waters in two distinct runs during the summer–autumn period. The offshore-migrating fish overwintered in deep Laurentian Channel waters, returning inshore in April. Individual migration routes and migration timing were variable, indicating that the cod did not aggregate in large schools during the seasonal migration events.

Unsteady disturbances of streaming motions around bodies

1989 ◽  
Vol 209 ◽  
pp. 385-403 ◽  
Author(s):  
H. M. Atassi ◽  
J. Grzedzinski
Keyword(s):  
Wave Equation ◽  
Body Surface ◽  
Source Term ◽  
The Body ◽  
Entire Body ◽  
Two Dimensional ◽  
Mean Flow ◽  
Inhomogeneous Wave ◽  
Inhomogeneous Wave Equation ◽  
The Mean

For small-amplitude vortical and entropic unsteady disturbances of potential flows, Goldstein proposed a partial splitting of the velocity field into a vortical part u(I) that is a known function of the imposed upstream disturbance and a potential part ∇ϕ satisfying a linear inhomogeneous wave equation with a dipole-type source term. The present paper deals with flows around bodies with a stagnation point. It is shown that for such flows u(I) becomes singular along the entire body surface and its wake and as a result ∇ϕ will also be singular along the entire body surface. The paper proposes a modified splitting of the velocity field into a vortical part u(R) that has zero streamwise and normal components along the body surface, an entropy-dependent part and a regular part ∇ϕ* that satisfies a linear inhomogeneous wave equation with a modified source term.For periodic disturbances, explicit expressions for u(R) are given for three-dimensional flows past a single obstacle and for two-dimensional mean flows past a linear cascade. For weakly sheared flows, it is shown that if the mean flow has only a finite number of isolated stagnation points, u(R) will be finite along the body surface. On the other hand, if the mean flow has a stagnation line along the body surface such as in two-dimensional flows then the component of u(R) in this direction will have a logarithmic singularity.For incompressible flows, the boundary-value problem for ϕ* is formulated in terms of an integral equation of the Fredholm type. The theory is applied to a typical bluff body. Detailed calculations are carried out to show the velocity and pressure fields in response to incident harmonic disturbances.

The metabolic response to severe head injury

1984 ◽  
Vol 60 (4) ◽  
pp. 687-696 ◽  
Author(s):  
Guy L. Clifton ◽  
Claudia S. Robertson ◽  
Robert G. Grossman ◽  
Susan Hodge ◽  
Richard Foltz ◽  
...  
Keyword(s):  
Body Surface ◽  
Nitrogen Balance ◽  
Metabolic Response ◽  
The Body ◽  
Nitrogen Excretion ◽  
Content Type ◽  
Head Injured ◽  
The Mean ◽  
Metabolic Expenditure ◽  
Injured Patients

✓ Caloric expenditure and nitrogen balance were measured in 14 steroid-treated comatose head-injured patients acutely and up to 28 days after injury. During this period patients were fed with a continuous enteral infusion of a formula containing 2 Kcal/cc and 10 gm nitrogen/liter. Indirect calorimetry was carried out for 102 patient-days. The mean resting metabolic expenditure (RME) for nonsedated nonparalyzed patients was 138% ± 37% of that expected for an uninjured resting person of equivalent age, sex, and body surface area. Nitrogen excretion was measured for 135 patient-days. The mean excretion was 20.2 ± 6.4 gm/day. The mean protein caloric contribution was 23.9% ± 6.7% and was greater than 25% for six patients, compared to normal values of 10% to 15%. Despite hyperalimentation, positive nitrogen balance for any 3-day period was achieved in only seven patients, and required replacement of 161% to 240% of RME with enterally administered formula. Head-injured patients had a metabolic response similar to that reported for patients with burns of 20% to 40% of the body surface.

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.

scholarly journals Trichodina magna Van As and Basson, 1989 (Ciliophora: Peritrichia) from cultured Nile tilapia in the state of Santa Catarina, Brazil

2008 ◽  
Vol 68 (1) ◽  
pp. 169-172 ◽  
Author(s):  
ML. Martins ◽  
L. Ghiraldelli
Keyword(s):  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Original Description ◽  
The State ◽  
The Body ◽  
Fish Ponds ◽  
Santa Catarina ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Mean Diameter ◽  
The Mean

Specimens of Trichodina magna Van As and Bassson, 1989 (Ciliophora: Peritrichia) from the Nile tilapia Oreochromis niloticus collected from October 2004 to June 2005 in fish ponds situated in three regions of Santa Catarina State, Brazil are described here. Wet smears of skin and gills were prepared in the field, air dried, impregnated with Klein’s dry silver method and Giemsa’s solution. From a total of 146 examined fish, 36 were parasitized on the skin, 14 in the gills and 33 on the skin and gills, simultaneously. The mean diameter of the body of the specimens of T. magna was 84.3 ± 12.6 µm, adhesive disc 60.7 ± 10.0 µm, denticulate ring, 38.3 ± 7.4 µm, consisting of 26 (23 to 29) denticles. The only distinguishable difference from the original description was the fact that the ray of the denticle is anteriorly directed and does not extend over the y + 1 axis.

Reproductive interactions between fugitive farmed and wild Atlantic cod (Gadus morhua) in the field

2010 ◽  
Vol 67 (8) ◽  
pp. 1221-1231 ◽  
Author(s):  
Justin J. Meager ◽  
Jon Egil Skjæraasen ◽  
Anders Fernö ◽  
Svein Løkkeborg
Keyword(s):  
Mating System ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Dynamics ◽  
Wild Fish ◽  
Spawning Ground ◽  
Males And Females ◽  
Farmed Escapees ◽  
Ultrasonic Transmitters

Atlantic cod ( Gadus morhua ) are being increasingly farmed in net pens adjacent to coastal populations that are currently at historic lows. One concern is that farmed escapees enter local spawning shoals and mate with wild cod. We tested for the potential of escaped farmed cod to interact and hybridize with wild fish by examining the spatial dynamics of, and associations between, fish tagged with ultrasonic transmitters. Based on these data, we also investigated the basic mating system of cod in the field. The spawning ground was best described as a lekking arena. Wild males aggregated near the seafloor and associations between individuals were frequent. Wild females had a pelagic and dispersed distribution and rarely associated with each other. Associations between individual wild males and females were also infrequent. Farmed males rarely associated with wild fish and had core usage areas above the wild males, suggesting that they were not admitted into the spawning arena. Farmed females were over the spawning arena more frequently than wild females and often associated with wild males at the depth of the spawning arena, indicating potential mating with wild males and the possibility of courtship interference. Hence, hybridization between escaped farmed and wild cod is likely.

The effects of isolation and colonization history on the genetic structure of marine-relict populations of Atlantic cod (Gadus morhua) in the Canadian Arctic

2006 ◽  
Vol 63 (8) ◽  
pp. 1830-1839 ◽  
Author(s):  
David C Hardie ◽  
Roxanne M Gillett ◽  
Jeffrey A Hutchings
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Allelic Diversity ◽  
Canadian Arctic ◽  
Environmental Stochasticity ◽  
Arctic Lakes ◽  
The Arctic ◽  
Effective Population ◽  
Eastern Canada ◽  
High Allelic Diversity

The genetic consequences of extended periods at low population size are fundamental to the conservation of depleted species such as the Atlantic cod (Gadus morhua). We compared microsatellite genetic variability among cod populations in Canadian Arctic lakes with that of Gilbert Bay resident and inshore cod from eastern Canada. The Arctic populations had the lowest genetic diversity and were the most strongly genetically structured and distinct. By contrast, eastern Canadian samples expressed high allelic diversity and were not significantly genetically structured or distinct relative to each other, whereas Gilbert Bay resident cod were intermediate to the Arctic and eastern Canadian groups. Our results are consistent with the hypothesis that the Arctic populations were colonized between 8000 and 5000 years ago and have experienced little or no gene flow since that time. Despite isolation at the extreme of the species' range, the Arctic populations have retained relatively high heterozygosities and high genetic effective population sizes relative to census sizes (Ne–Nc ratios). Potential explanations for this include the absence of fishing pressure, allowing for the persistence of large, highly fecund individuals, as well as biotic (e.g., absence of planktivores) and abiotic (e.g., low environmental stochasticity) factors in the Arctic lakes that minimize individual variance in reproductive success.

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