Migrations and Intermingling of Atlantic Cod (Gadus morhua) Stocks of the Newfoundland Area

1974 ◽  
Vol 31 (6) ◽  
pp. 1073-1092 ◽  
Author(s):  
Wilfred Templeman
Keyword(s):  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Southeastern Part ◽  
Vertical Movements ◽  
Bank Stock ◽  
Avalon Peninsula

Commercial recaptures of 26% (22.5% in years after the tagging year) of 18,822 Atlantic cod (Gadus morhua) 50 cm or more in length that were tagged mainly in the feeding season at 13 localities in the Newfoundland area in 1954–55 elucidated migrations and intermingling of cod of various stocks or stock complexes. Cod of the northern Gulf of St. Lawrence stock migrated southward from the Strait of Belle Isle to winter on the northern side of Cabot Strait and vicinity, mingling there with the Burgeo Bank stock. Cod of the Newfoundland–Labrador complex tagged at three sites mingled along the east coast of Newfoundland and off southern Labrador and with cod of the northern Gulf stock near the Strait of Belle Isle, of the Avalon–Burin stock complex off the Avalon peninsula, and of a Grand Bank stock on the northern part of the bank. Though cod tagged off the Avalon peninsula and on St. Pierre Bank were recaptured mainly near the tagging sites, some moved as far north as Labrador, to the southern Grand Bank, and to Cabot Strait. Fish tagged on the northwestern Grand Bank were recaptured mainly at the tagging site but also elsewhere on the bank and off the east coast of Newfoundland. Those tagged on the Southeast Shoal of the Grand Bank were recaptured mainly on the southeastern part of the bank though some moved as far as southeastern Newfoundland. Those tagged on Burgeo Bank mingled with the Avalon–Burin stock complex, including the St. Pierre Bank component, but mainly with the Northern Gulf stock in winter–spring near Cabot Strait.Cod 90–129 cm long at tagging were recaptured at shorter distances from the tagging sites than 50–89-cm cod. Tagging–recapture distances also increased with increasing age for cod of the smaller length ranges on tagging. In their vertical movements, most tagged cod moved to shallow water in late spring or early summer and retreated gradually to deeper water from late summer to early spring. Some remained in deep water throughout the year.Recapture rates at different size ranges varied with area but were not greatly different at length ranges from 50–59 to 80–94 cm, which included 95% of the tagged cod.

scholarly journals Movement patterns of Atlantic cod in Gilbert Bay, Labrador: evidence for bay residency and spawning site fidelity

2000 ◽  
Vol 80 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
John M. Green ◽  
Joseph S. Wroblewski
Keyword(s):  
Site Fidelity ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Movement Patterns ◽  
Release Site ◽  
Late Summer ◽  
Early Summer ◽  
Open Ocean ◽  
Tracking Data ◽  
Spawning Site

During three consecutive years of observation 23 Atlantic cod (Gadus morhua) were tagged with ultrasonic transmitters as part of two experiments to determine the movement patterns of adult cod in the genetically distinctive population inhabiting Gilbert Bay, Labrador. Individual cod were relocated for periods up to 15 months, indicating year-round residency within the bay despite unimpeded access to the open ocean. The tracking data show that individual cod have a strong homing tendency. In experiment 1 displaced cod returned (homed) to their place of capture in a small arm separated from the rest of the bay by a shallow sill while non-displaced fish remained at their capture site. In experiment 2 some cod remained within 2 km of their capture/release site, a spawning area, while others ranged widely in Gilbert Bay before returning to this site. Whether an individual ranged widely or had more restricted movements was not related to size. Cod exhibited wider ranging movements in the spring and early summer, following spawning, than in the late summer and early autumn. The return of Gilbert Bay cod to specific locations in the inner part of the bay to overwinter and spawn is evidence of one mechanism that could have led to their genetic distinctiveness.

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 Influence of a Municipal Solid Waste Landfill on the Surrounding Environment: Landfill Vegetation as a Potential Risk of Allergenic Pollen

2019 ◽  
Vol 16 (24) ◽  
pp. 5064 ◽  
Author(s):  
Magdalena Daria Vaverková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Eugeniusz Koda ◽  
Jana Červenková ◽  
...  
Keyword(s):  
Plant Species ◽  
Low Cost ◽  
Late Summer ◽  
Cost Effective ◽  
Early Spring ◽  
Early Summer ◽  
Allergenic Pollen ◽  
Grass Species ◽  
Vegetation Monitoring ◽  
Growing Seasons

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.

Infection of Lumpfish (Cyclopterus lumpus) with Larvae and of Atlantic cod (Gadus morhua) with Adults of the Copepod, Lernaeocera branchialis, in and adjacent to the Newfoundland area, and Inferences Therefrom on Inshore–Offshore Migrations of Cod

1976 ◽  
Vol 33 (4) ◽  
pp. 711-731 ◽  
Author(s):  
Wilfred Templeman ◽  
V. M. Hodder ◽  
A. M. Fleming
Keyword(s):  
Intermediate Host ◽  
West Coast ◽  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Adult Parasite ◽  
Infection Rates ◽  
The West ◽  
Cyclopterus Lumpus ◽  
Branchial Arches

The lumpfish, Cyclopterus lumpus, was found to be a common intermediate host of the larvae of the copepod, Lernaeocera branchialis, in the Newfoundland and neighboring areas. Large numbers of these larvae occurred on the gills of lumpfish from inshore Newfoundland areas from the latter half of June to the first half of August, whereas only minor infection was found in any month in offshore areas. Some larvae of the year reached the final or seventh stage on the intermediate host in May on the west coast of Newfoundland and in June on the east coast. By July on the west coast and early August on the east coast, this was by far the most numerous stage present. The larvae were attached mainly near the tips of the gill filaments. Most larvae were attached to the gills of the first two branchial arches, less to those of the third, and much less to those of the fourth. There were more larvae on the right than on the left gills. Infection of the final host Atlantic cod (Gadus morhua), by stage-7 female L. branchialis was apparently mainly inshore.Adult L. branchialis on Atlantic cod, typically located near the anterior ventral apex of the branchial arches, were numerous throughout the year in the areas of high infection. Infection rates of cod with the adult parasite were usually considerably higher near the coast than farther offshore, the rates declining with distance from the coast. Rates of infection with the adult parasite usually increased from the smaller to intermediate cod lengths and declined rapidly at greater lengths. Infection rates were found useful as evidence of inshore and offshore migrations of cod. Infection with the copepod apparently delayed sexual maturity in cod. Most infected cod (86%) had one adult copepod and declining numbers (12–0.05%) possessed two to five adult copepods. The Greenland cod, G. ogac, was the only other fish of the area found to be highly infected with adult L. branchialis.

Sub-seasonal streamflow predictions by combining numerical weather models and re-analysis data in alpine catchments

2021 ◽  
Author(s):  
Mattia Zaramella ◽  
Susen Shtrestha ◽  
Mattia Callegari ◽  
Alice Crespi ◽  
Felix Greifeneder ◽  
...  
Keyword(s):  
Model Simulation ◽  
Late Summer ◽  
Analysis Data ◽  
Early Spring ◽  
Early Summer ◽  
Lead Times ◽  
Streamflow Prediction ◽  
Reanalysis Dataset ◽  
Numerical Weather ◽  
Basin Scale

<p>The European Center for Medium-Range Weather Forecasts (ECMWF) has presented in 2017 its latest seasonal forecasting system, SEAS5, available at 1° spatial resolution and daily timestep. More recently, in 2019, the ERA5 reanalysis dataset was released, replacing ERA Interim in providing climatic variables at a finer spatial and temporal resolution (30 km and hourly respectively). The use of such numerical weather predictions and re-analysis data has increased following the need for skills in planning water resources and preventing hydrogeological risk, as demanded by policy makers, energy stakeholders and public authorities. In this work, we apply at a sub-seasonal timescale the ECMWF-SEAS5 hindcast dataset to assess its prediction skills in the upper Adige river basin in the Eastern Italian Alps. The classical Extended Streamflow Prediction (ESP) framework was designated as a benchmark to assess ECMWF scores over the reference, a model simulation calibrated and validated on the runoff observed from 16 sub-basins and size spanning from 50 to 6900 km<sup>2</sup>. Before application, ECMWF was downscaled and adjusted to the ERA5 re-analysis data by means of a Quantile Mapping (QM) technique. The analysis was conducted over 23 hindcast years from 1993 to 2016 exploiting the semi-distributed basin-scale hydrological model (ICHYMOD). We showed that the sub seasonal QPF-based forecasts have advantages over the ESP, although, generally their skill deteriorates in lead times after day 15. Moreover, ECMWF predictions better perform during early-spring snowmelt and late summer. During late spring and early summer, the forecast skills of the two frameworks vary from basin to basin depending on specific features and lead times.  </p>

scholarly journals Catch-and-release of Atlantic cod (Gadus morhua): post-release behaviour of acoustically pretagged fish in a natural marine environment

2015 ◽  
Vol 72 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Keno Ferter ◽  
Klaas Hartmann ◽  
Alf Ring Kleiven ◽  
Even Moland ◽  
Esben Moland Olsen
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Sublethal Effects ◽  
Atlantic Cod ◽  
Small Scale ◽  
Marine Environments ◽  
Vertical Movements ◽  
Catch And Release ◽  
Diel Vertical Migrations ◽  
In The Wild

Studying the sublethal effects of catch-and-release (C&R) is challenging, as there are several potential sources of bias. For example, if behavioural alterations immediately after the release event are to be studied, separation of tagging effects from actual C&R effects is required, which is a challenge in the wild, particularly in marine environments. To investigate the effects of C&R on Atlantic cod (Gadus morhua) in their natural environment, 80 cod were caught in fyke nets, fitted with acoustic transmitters, and released. After recovery from tagging and handling for at least 14 days, nine individuals were recaptured and released at least once during experimental angling, following best release practice. All cod survived the C&R event and did not show any large-scale behavioural changes (i.e., changes in diel vertical migrations). However, analysis of small-scale vertical movements showed that three individuals underwent short-term alterations (e.g., reduced or increased swimming activity). This study showed that pretagging fish with acoustic transmitters before experimental angling is an option when investigating fish behaviour immediately after the release event in marine environments. Moreover, release guidelines for cod should be developed, as cod can recover quickly if caught in shallow waters (<20 m) and properly handled and released.

scholarly journals Population biology of eyeflukes in fish from a large fluvial ecosystem: the importance of gulls and habitat characteristics

2001 ◽  
Vol 79 (6) ◽  
pp. 1102-1113 ◽  
Author(s):  
D J Marcogliese ◽  
S Compagna ◽  
E Bergeron ◽  
J D McLaughlin
Keyword(s):  
Population Biology ◽  
Yellow Perch ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Habitat Characteristics ◽  
Vitreous Humour ◽  
Late Fall ◽  
Golden Shiners ◽  
St Lawrence River

Spottail shiners (Notropis hudsonius) were monitored for eyeflukes monthly at four sites in the St. Lawrence River, Quebec, from spring through autumn in 1997 and 1998. In general, mean abundance of Diplostomum spp. in the lens of spottail shiners was highest at sites near large ring-billed gull (Larus delawarensis) colonies and was higher in 1998 than in 1997. Population studies demonstrated a major period of recruitment in the late summer – early autumn. Mean abundance increased between November and May, when sampling was logistically not possible, reflecting late-fall or early-spring recruitment. Golden shiners (Notemigonus crysoleucas) and small yellow perch (Perca flavescens) were monitored at a single site (Île aux Ours) in 1997 and 1998. Mean abundance of Diplostomum spp. in the lens of golden shiners at Île aux Ours was higher in 1998 than in 1997. Recruitment occurred in the early summer and between November and May, suggesting late-fall or early-spring transmission. Mean abundance decreased between August and October in both years. Yellow perch at Île aux Ours were infected with four different parasite species in their eyes. Mean abundance of Diplostomum spp. in the vitreous humour or retina increased during the summer and fall and then decreased between the fall and following spring. Diplostomum spp. in the lens increased in abundance in the early summer, and then decreased during the fall. Both Tylodelphys scheuringi and Neascus spp. in the vitreous humour were more abundant in 0+ than in 1+ perch. Mean abundance of T. scheuringi increased over the summer in 1997 and then dropped to zero in the same cohort over winter, suggesting that the parasite lives for only 1 year. Neascus spp. only were found in 1998. Distributional data, together with seasonal information, suggest that habitat characteristics contribute significantly to the abundance of Diplostomum spp. along the St. Lawrence River. Proximity to gull colonies enhances abundance, but higher rates of predation at wetland sites depress abundance and restrict the accumulation of parasites.

Movements of Atlantic Cod (Gadus Morhua) Within the Spring Thermocline in Trinity Bay, Newfoundland

1995 ◽  
Vol 75 (2) ◽  
pp. 265-284 ◽  
Author(s):  
J.S. Wroblewski ◽  
Sally V. Goddard ◽  
R. Kent Smedbol ◽  
Wade L. Bailey
Keyword(s):  
Surface Waters ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Antifreeze Protein ◽  
Early Spring ◽  
Subzero Temperature ◽  
Cold Adapted ◽  
Protein Levels ◽  
Trap Fishery ◽  
Trinity Bay

Using depth-telemetering, sonic tags orally inserted into the stomachs of Gadus morhua (Pisces: Gadiformes) found over-wintering in Trinity Bay, Newfoundland, the movements of individual fish were observed as surface waters warmed in early spring. Physiological measurements (antifreeze protein levels in the blood) indicate that many cold-adapted, bay cod change their thermal regime at this time. Fish acclimatized to subzero water temperatures enter the newly-formed thermocline and become available to a cod trap fishery. Most sonically-tagged fish resided in 0–1°C waters along the shoreline. Tracking data confirmed indications from declining antifreeze protein levels that cold-adapted cod, having moved into shallow waters in early spring, do not return to deeper, subzero-temperature waters for any appreciable time. At night some cod swam pelagically near the surface. Fish moved at times in the same direction as the tidal current, but ground speeds were several times greater than current velocities. Nocturnal pelagic swimming was also observed during the summer when temperatures within the thermocline exceeded 10°C.

Peculiarities in ovarian structure leading to multiple-year delays in oogenesis and possible senescence in Atlantic cod, Gadus morhua L.

2000 ◽  
Vol 78 (10) ◽  
pp. 1840-1844 ◽  
Author(s):  
Rick M Rideout ◽  
Margaret PM Burton
Keyword(s):  
Atlantic Ocean ◽  
Reproductive Cycle ◽  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Spawning Season ◽  
Northwest Atlantic ◽  
Spawning Cycle ◽  
Ovarian Structure

Five specimens of female Atlantic cod, Gadus morhua L., four collected during regular surveys of the northwest Atlantic Ocean, had ovarian structures that suggested that multiple-year interruptions were occurring in the spawning cycle of these fish. One specimen was experiencing a minimal 2-year delay in its reproductive cycle because the ovary contained only oogonia, which would have had to mature before any spawning could occur. Two other specimens did not contain oogonia or perinucleolar-stage oocytes, suggesting that these ovaries were senescent. Another two ovaries, one removed from a broodstock female and one taken from a female collected off Newfoundland's east coast, contained large masses of resorbing hyaline oocytes, which would likely have impaired the normal release of hydrated oocytes in the next spawning season.

Historical analysis of Pan I in Atlantic cod (Gadus morhua): temporal stability of allele frequencies in the southeastern part of the species distribution

2007 ◽  
Vol 64 (10) ◽  
pp. 1448-1455 ◽  
Author(s):  
Einar Eg Nielsen ◽  
Brian R MacKenzie ◽  
Eydfinn Magnussen ◽  
Dorte Meldrup
Keyword(s):  
Species Distribution ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Temporal Stability ◽  
Historical Analysis ◽  
Allele Frequencies ◽  
Degraded Dna ◽  
Frequency Variation ◽  
Genetic Stock ◽  
Southeastern Part

We investigated temporal genetic differentiation at the pantophysin (Pan I) locus in four Atlantic cod (Gadus morhua) populations from the southeastern part of the species distribution: the Baltic Sea, the North Sea, the Faroe Plateau, and the Faroe Bank. Historical otolith collections enabled investigation of allele frequency variation over time periods up to 69 years employing Pan I primers specifically designed for partially degraded DNA. Small and nonsignificant temporal changes in Pan I allele frequencies were observed in the four populations. Simultaneous microsatellite analysis revealed similar temporal genetic stability with temporal FST values ranging from 0 to 0.006, suggesting limited demographic changes. Sea surface temperature, which has been suggested as the primary driver for the geographical distribution of Pan I alleles in cod, showed no long-term trend although temperature has increased since the mid-1990s. Our study demonstrates that populations in the southeastern part of the species range has been characterized by very high frequencies of the Pan IA allele for many decades, and accordingly, Pan I serves as a reliable marker for genetic stock identification on a macrogeographical scale.

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