Eastern Newfoundland Research Articles

Food of winter flounder Pseudo-pleuronectes americanus in a sea urchin dominated community in eastern Newfoundland

Food of winter flounder Pseudo-pleuronectes americanus in a sea urchin dominated community in eastern Newfoundland

Variation of Vertebral Numbers with Fish Length in Atlantic Cod (Gadus morhua) of the Eastern Newfoundland Area, 1947-71

Means of vertebral numbers in cod samples collected in 1947-71 from the eastern Newfoundland and Labrador area were compared by length-ranges. In NAFO Div. 2GHJ and 3KL, the northern-type high-vertebral means (usually over or slightly below 55) were usually present at the length-ranges of lesser length, declining toward lower means at greater sizes. The high-vertebral-type mean extended to higher length-ranges northward than southward. In coastal areas of Div. 2GHJ and 3K, the means at the same length-ranges tended to be somewhat lower than offshore. Means at the same length-ranges for the above areas were usually a little higher in the earlier period, 1947-55, than in the later period, 1958-71. Throughout the area (not including Div. 3M) offshore and inshore vertebral means at the same length-range and period were typically lower in the southern than in the adjacent northern area. The vertebral means of the relatively isolated cod stock on Flemish Cap (Div. 3M) were intermediate between the northernand the southern-types, and on the southern Grand Bank (Div. 3NO) the means (usually below 54) were typically the lowest in the eastern Newfoundland area. Within each of these areas (Div. 3M and 3NO), means did not differ greatly by length-range and from the earlier to the later

Palaeomagnetism of early Cambrian Brigus red shale, eastern Newfoundland

Abstract Studies of the early Cambrian Brigus (BR) red shale exposed in Conception Bay yielded a single, stable mean remanence direction of D = 265°, I = + 58° (reverse polarity) before tilt correction and D = 279°, I = + 48°, k = 47, α 95 = 6.9°forN = 7 sites (25 samples) after correction for gentle tilt; the corresponding (North pole palaeopole) position is 27°S, 51°E (dp, dm = 6°, 9°). This magnetization is characterized by a linear vector trajectory at higher unblocking temperature ( T UB ) spectra (400-680° C). The magnetization directions at the low T UB range (400°C) are more variable from sample to sample, although they typically have steep downward inclinations, with no evidence of Kiaman overprinting. Marginal but not statistically significant improvement ( k = 44–77) in the grouping of site means after tilt correction suggests that the predominant, univectorial westerly remanance was probably acquired after deposition. Based on both geological and magnetic evidence, the Brigus Shale Formation appears to be remagnetized during Siluro-Devonian times. The position of the far-sided antipole BR (27°N, 129°W) located in the vicinity of the pole for the Cambrian Morrison River Formation (MR at 20°N, 146°W), which is discordant from the younger Palaeozoic (Late Ordovician-Carboniferous) poles reported for the Avalon Zone, is fortuitous. Since the magnetization of BR is most likely secondary, the magnetization is younger than the Iapetus closure date determined geologically (Late Ordovician). Consequently, the displacement of the Avalon Zone with respect to the North American craton cannot be estimated; the width of the Proto-Atlantic Ocean cannot be calculated.

Life History Parameters of Sand Lances (Ammodytesspp.) from the Coastal Waters of Eastern Newfoundland

Life History Parameters of Sand Lances (<i>Ammodytes</i>spp.) from the Coastal Waters of Eastern Newfoundland

Seasonal and annual variation in the diet of Atlantic cod (Gadus morhua) in relation to the abundance of capelin (Mallotus villosus) off eastern Newfoundland, Canada

Seasonal and annual variation in the diet of Atlantic cod (Gadus morhua) in relation to the abundance of capelin (Mallotus villosus) off eastern Newfoundland, Canada

Widespread hybridization between native Atlantic salmon, Salmo salar, and introduced brown trout, S. trutta, in eastern Newfoundland

Hybridization between native Atlantic salmon and introduced brown trout was found to occur at a mean frequency of 0.9% in Atlantic salmon populations in eastern Newfoundland. Hybrids were detected in five of the 10 watersheds studied, but consideration of sampling error suggests that they could have been present in the remaining five watersheds although they were not detected. The frequency found in the Newfoundland and other North American salmon populations is significantly greater than the 0.3% reported for salmon populations in the British Isles, and both are higher than frequencies observed in salmon populations in Sweden. The higher frequency in North America is in accord with the prediction that hybridization between species will be more frequent where one species is introduced than in areas where both are native.

Paleozoic paleogeography of North America, Gondwana, and intervening displaced terranes: Comparisons of paleomagnetism with paleoclimatology and biogeographical patterns

New paleomagnetic data have become available in the past 5 yr that require modifications in previously published paleogeographic reconstructions for the Silurian and Devonian. In this paper, the new paleopoles are compared to published paleogeographic models based on paleoclimatologic and biogeographic data. The data from the three fields of paleomagnetism, paleoclimatology, and biogeography are generally in excellent agreement, and an internally consistent paleogeographic evolutionary picture of the interactions between North America, Gondwana, and intervening displaced terranes is emerging.During the interval of the Ordovician, Silurian, and Devonian, North America stayed in equatorial paleoposition, while rotating counter-clockwise. The northwest African part of Gondwana was in high southerly latitudes during the Late Ordovician and was fringed by peri-Gondwanide terranes, such as southern Europe (Armorica) and Avalonian basement blocks now found in eastern Newfoundland, Nova Scotia, the Boston Basin, the Appalachian Piedmont, and northern Florida. Subsequently, Gondwana and the peri-Gondwanide terranes displayed rapid drift with respect to the pole. This drift translates into the following pattern of movement for northwest Africa. During the latest Ordovician-Early Silurian, this area moved rapidly northward from polar to subtropical latitudes, followed by equally rapid southward motion from subtropical to intermediate (about 50°S) paleolatitudes during the Late Silurian-Middle Devonian. It is likely that significant east-to-west motion accompanied the latter shift in paleolatitudes, with the Caledonian-Acadian orogeny the result of Silurian to Early Devonian convergence and collision between Gondwana and North America. This collision sandwiched several of the intervening displaced terranes between Gondwana and North America. Subsequent to this collision, Gondwana was separated in the Late Devonian by a medium-width ocean from North America and the Avalonian and southern European blocks which were left behind adjacent to North America. This new ocean closed during the Carboniferous, and the resulting convergence and collision were the cause of the Hercynian-Alleghanian orogenic belt. Problems remaining for future research, besides the further gathering of reliable paleopoles, involve the uncertain pre-Devonian position of the southern British Isles in this scenario and the very rapid velocity with respect to the pole that results from the rapid Late Ordovician-Silurian apparent polar wander for Gondwana.

Migration of Postsmolt Atlantic Salmon, Salmo salar, Off Northeastern Newfoundland, As Inferred by Tag Recoveries in a Seabird Colony

Northern gannets, Sula bassanus, and possibly other seabird species nesting on Funk Island off northeastern Newfoundland preyed on postsmolt Atlantic salmon, Salmo salar. Salmon comprised less than 1% of 2928 regurgitated food samples collected from gannets at the colony. Ten smolt tags were recovered in and near the gannetry during August or September in 1984 through 1986. The tags were from smolts released 3–4 mo earlier in the Penobscot River (Maine) (n = 7) and one each from the Saint John River (New Brunswick) and the Lower Clyde and LaHave rivers (Nova Scotia). These recoveries provide evidence that postsmolt Atlantic salmon from rivers in New England, the Bay of Fundy, and the Atlantic coast of Nova Scotia migrate off eastern Newfoundland This migratory pattern contrasts with that of postsmolts from the Gulf of St. Lawrence, which tend to move northwards along Newfoundland's west coast and through the Strait of Belle Isle.

Early deformation in the Caledonian-Appalachian orogen

Summary Deformation isotopically dated at 1100–1000 Ma has been recorded in the Moine rocks of N Scotland and may be related to the latest stages of Grenville orogenesis of N America. Late Precambrian orogenesis is widely recorded in the dispersed fragments of Avalonia particularly in the eastern Appalachians, eastern Newfoundland and southern Britain. Localized evidence for late Cambrian-early Ordovician orogenesis is forthcoming in the Appalachians (Penobscot) in Scandinavia (Finnmarkian) and in Scotland and Ireland (Grampian).

Coastal Upwelling and Oikopleura Occurrence ("Slub"): A Model and Potential Application to Inshore Fisheries

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 &lt; 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 &lt; 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.

Metabasalts of the Harbour Main Group, eastern Newfoundland: a paleomagnetic study

The Avalon peninsula of Newfoundland is distinguished from the central part of that island by its large proportion of Late Precambrian rocks. The study area is located in the Colliers Bay and Bauline areas at longitude 53° W and latitude 47° 30'N. Fifty-two oriented samples (140 specimen) were collected on ten different sites in the Harbour Main Group volcanics which are older than 610 Ma and younger than 770 Ma. Remanent magnetization and magnetic susceptibility were measured. Both alternating field and thermal demagnetizations were used to characterize the stability of magnetizations. Four components of magnetization (A, B, C, D) were isolated and their mean directions (317, −22, 175, + 34, 190, −27, 266, −37) are corresponding to paleopoles at 20°N, 172°E, 24°N, 132°E, 56°N, 109°E, and 18°S, 205°E, respectively. Component D is encountered on two sites only and is largely overprinted by the present Earth's field. Component C is obtained in seven sites, is characterized by a significantly negative fold test and is thus presumed to be secondary. Components A and B are found on most sites and are also characterized by negative fold tests but the test is more significant for B than A. In addition, the larger unblocking temperatures and median destructive fields of component A suggest that it is older than B. A comparison of the paleopoles obtained with the apparent polar wander path for North America indicates that the age of acquisition of magnetization for C is Carbo-Permian and for B it is Upper Devonian, the age of D remains unresolved. The pole of component A obtained in this study lies close to that of component A obtained in a previous study on the Finn Hill ignimbrites, it is located within the Devonian-Late Hadrynian interval. It is tentatively interpreted as the signature of the Cadomian orogenic event that occurred at approximately 600 Ma.

Ocean pout (Macrozoarces americanus (Bloch and Schneider) (Pisces: Zoarcidae)) predation on green sea urchins (Strongylocentrotus droebachiensis (O.F. Mull.) (Echinodermata: Echinoidea)) in eastern Newfoundland

The diet of ocean pout was studied by analysis of the contents of the gastrointestinal tracts of 151 individuals collected from the green sea urchin dominated rocky subtidal in eastern Newfoundland. Green sea urchins constituted 62% of the overall diet by weight. The brittle star, Ophiopholus aculeata, constituted 7% of the diet, while the remainder was miscellaneous invertebrates and fish (mainly capelin and billfish). From April to July, when the fish are inshore and feeding, before breeding, the average ocean pout contained 56.3 g of urchins. This is a biomass of urchins equivalent to that in 0.106 m2 of the middle of the urchin-dominated zone. During the inshore feeding period, the average male ocean pout contained 65.0 g of urchins, and the average female contained 47.5 g, biomass values representing 0.122 and 0.089 m2, respectively. Assuming that the contents of the gastrointestinal tract turn over every 3 days, and assuming a 1:1 sex ratio, it is calculated that while inshore, before a seasonal reduction in feeding associated with the spawning season, each ocean pout consumes on average 2.29 kg of urchins (males 2.64 kg, females 1.93 kg). Based on these figures, a density of one ocean pout pair per 8.6 m2 would be required to completely consume the mean biomass (532 g m−2) of urchins present in the urchin-dominated zone in one season.

Collision along an irregular margin: a regional plate tectonic interpretation of the Canadian Appalachians

An idealized plate tectonic model for the pre-Carboniferous development of the Canadian Appalachians explains the 400 km dextral offset of tectonostratigraphic zones from Quebec and northern New Brunswick to Newfoundland and the up to 600 km offset of oppositely verging belts of Acadian deformation from the Gaspé Peninsula to eastern Newfoundland. It is proposed that these offsets, which occur at the St. Lawrence promontory, result from the collision of an irregular North American passive continental margin with island arc and continental crust to the east, along an east-dipping subduction zone. The line of subduction is assumed to have been linear and the subducting slab to have maintained its mechanical integrity during collision. A "jigsaw fit" of the opposite sides of the Iapetus Ocean is made unnecessary by invoking lithospheric delamination and tectonic wedging during the Acadian orogeny in Newfoundland. The model is consistent with surface geology and recent deep seismic reflection observations from north of Newfoundland.

Wind-Forced Hydrodynamics and Their Interaction with Larval Fish and Plankton Abundance: A Time-Series Analysis of Physical–Biological Data

We evaluated methods to measure simultaneously biological and physical properties essential for estimating short-term mortality of larval fish. We used the data to test Templeman's watermass exchange hypothesis and the associated safe-site hypothesis. Synoptic estimates of larval capelin (Mallotus villosus) and microzooplankton particle density were obtained simultaneously with a scale resolution of 200 m (horizontal), 2–4 m (vertical) and 6–8 h (temporal) in a 1-km2 coastal embayment in eastern Newfoundland. Statistically significant population estimates were derived from multiple regression models incorporating a limited number of samples. Spectral analysis of wind and current time-series and analysis of large-scale temperature oscillations were consistent with Templeman's hypothesis. Nearshore current responded to cross-shore wind forcing at periods of 2–6 d. Larval capelin abundance oscillations were coherent with wind and with current at periods of ~5 d, consistent with the watermass exchange and safe-site hypotheses. Although larvae and microzooplankton abundances showed similar spectral density and were in phase, their coherence was weak. Integrated measures of onshore wind and of the onshore–offshore wind spectrum were correlated, and either can be used as a composite measure of the considerable interannual variation evident in the frequency, magnitude, and duration of onshore winds, and hence of watermass exchange.

Atlantic wolffish (Anarhichas lupus L.; Pisces: Anarhichidae) predation on green sea urchins (Strongylocentrotus droebachiensis (O.F. Mull.); Echinodermata: Echinoidea) in eastern Newfoundland

The diet of the Atlantic wolffish was studied by examining the contents of the gastrointestinal tracts of 90 individuals collected from the sea urchin dominated rocky subtidal in eastern Newfoundland. Green sea urchins comprised 75% of the overall diet by weight. Horse mussels ranked second but comprised only 9.5% of the diet. The remainder of the diet consisted of several species of invertebrates and fish. The average (over the whole season) wolffish contained 120 g of urchins, equivalent to the biomass of urchins on 0.23 m2 in the middle of the urchin-dominated zone. During April–September, prior to breeding, the average male wolffish contained 174 g of urchins, and the average female contained 85 g of urchins, biomass values representing, respectively, 0.33 and 0.16 m2. Assuming that the contents of the gastrointestinal tract turn over every 3 days, it was calculated that during May through August each wolffish consumes on average 5.29 kg of urchins (males, 7.09 kg; females, 3.50 kg). Based on these figures, a density of 1 wolffish pair per 20 m2 would be required to consume the mean biomass (532 g m−2) of urchins present in the urchin-dominated zone in 1 year.

Palaeomagnetism of porphyritic stocks and rhyolite sills, Avalon Zone of eastern Newfoundland

The eastern segment of the Appalachian orogen is largely underlain by late Precambrian (Hadrynian) rocks affected by the Avalonian, Acadian and possibly Alleghenian orogenies. The provenance of the Avalon Zone of Newfoundland is uncertain. The region investigated in this segment consists of porphyrite stocks and sills (laccoliths) intrusive into the sedimentary, tuffaceous and volcanic rocks of the Harbour Main Group and rhyolite sills intrusive into the porphyrites. Some 55 oriented samples (148 specimens) collected at 11 sites were thermally (20–650°C) and AF (0.05–100 mT) demagnetized. Three components of magnetization were isolated: C (311°, +48°, α 95 = 11°, k = 21, 10 sites), A (13°, +37°, α 95 = 14°, k = 22, 6 sites), and B (67°, +45°, α 95 = 15°, k = 27,5 sites). Based on coercivity spectra, unblocking temperatures, frequency distribution and precision parameters of the respective components, it is suggested that component C is older than component A which is turn is older than component B. The palaeopoles of components C, A and B are: 211°E, 48°N ( d p = 9.8°, d m = 14.7°); 101°E, 61°N ( d p = 9.6°, d m = 16.4°); 33°E, 34°N ( d p = 12°, d m = 19°), respectively. Component C is most probably primary. Component A is secondary and its pole is near that of Carboniferous and Early Permian North America poles, indicating that the porphyrites and the rhyolites were remagnetized in the late Palaeozoic. Component B remains unexplained; it is possible that it is an unresolved pseudo-component but it is more likely an overprint. There are few palaeomagnetic results for the late Precambrian period in Avalon terrane(s). The preliminary results of this study suggest the presence of a separate plate from North American at that time. These results will prove useful for the palaeoreconstruction of the continents (North Africa, northeast Europe) in the late Precambrian period.

Depth profiling of peat deposits with impulse radar

With the growing interest in peat as an energy fuel, the need for better inventories of this resource becomes increasingly important. Although conventional imaging sensors can provide information on the areal extent of peatlands, depth measurements must still be taken in the field in order to estimate the volume of material present. A recently completed program conducted in eastern Newfoundland suggests that impuse radar systems can provide depth information and volume estimates comparable to those obtained with manual measurement techniques. Ground-based data were acquired using 80- and 400-MHz radar systems and airborne data were collected using 80- and 120-MHz systems. For ground-based profiles, peat thickness of up to 8.1 m was clearly measureable. The airborne profile data were generally poorer in quality; however, depths of up to 4.8 m were successfully profiled from an altitude of 1.5 m. No significant seasonal variations were observed. Impulse radar techniques seem to be particularly useful for reconnaissance level surveys. Additional research is needed in order to develop a system suitable for airborne profiling. Key words: impulse radar, peat resources, peatlands, Newfoundland, depth, volume, profiling, airborne profiling, radar propagation.

Lakeward Migrations by Juvenile Atlantic Salmon, Salmo salar

Atlantic salmon parr, Salmo salar, undertook lakeward migrations from outlet streams in the Wings Brook system, eastern Newfoundland. Lakeward movement occurred from May through November, intensifying over a 6- to 8-wk period during spring. Parr remained in the lakes where they either matured (usually males) or smoltified (predominantly females) before returning to the streams. Mature parr emigrated from the lakes during autumn whereas smolts entered the streams during spring. Lakes provided conditions for increased parr growth and survival to the smolt stage relative to the riverine environment, and appeared to represent important overwintering habitat. Smolt production occurred almost entirely within the lakes. Parr movement into lakes could not be explained by physical environmental factors. Lakeward migrations appear to have an adaptive basis and can be explained as an evolutionarily stable reproductive tactic.

Population biology of green sea urchins on rocky barrens

Populations of the sea urchm Strongylocentrotus droebachensis in lughly grazed rocky barrens in eastern Newfoundland were sampled quantitatively in summer 1968. Comparisons among populations at an extremely exposed, a moderately exposed and a protected site show Mferences in recruitment and/or juve~ule survival, mortality and growth which may be caused by dfferences in temperature, wave exposure and food availability. Dense populations have an unusual growth pattern. Juveniles grow very slowly and at a certain point growth can virtually stop causing the formation of a stationary mode composed of several year classes of juveniles. The position of this conglomerate mode varies from 8 to 11 mm in test diameter at different locahons or depths. Urchins larger than 15 to 20 mm have a much lugher growth rate. I hypothesize that the slow growth of juvenlle urchins in dense populations is due to a severe food shortage coupled to their low mobhty. Urchins larger than 15 to 20 mm move actively about searching for macroalgal food; it is postulated that their increased growth rate is due to their mobllity and resultant greater access to food. If any of the larger actively foraging urchins were to die they would be replaced by the ever abundant juveniles, thus assuring the persistence of urchin-dominated barrens.

Chloritization and carbonatization of Cambrian volcanic rocks in eastern Newfoundland and southern New Brunswick, Canada

Cambrian basaltic flows and volcaniclastic rocks on the Avalon Peninsula of Newfoundland and from the Beaver Harbour area of southern New Brunswick show two phases of alteration which resulted in the formation of chlorite and carbonate in most of the rocks. Calculations which account for volume changes show that chlorite-forming reactions resulted in the addition of Mg, Sr, P and Mn and the removal of K, Rb, Ti, Zr, V and Fe from the Beaver Harbour rocks whereas Ca, Sr, Ba, Rb and K were removed and Ni, Cr, Ga, V and Mn added to Avalon samples. These results resemble those produced by basalt-seawater interaction, particularly in the Beaver Harbour case where Mg increases. In the Beaver Harbour rocks carbonate metasomatic reactions led to the addition of Ca, Sr, Na, Mg, P, Y and Zn and removal of Ba, Rb and K in proportion to the amount of carbonate added. Ca, Na, Sr and CO 2 were added and Mg removed in the Avalon rocks. With the exception of Mg removal (Avalon), the behaviour of most elements from both localities resembles that observed in systems with high CO 2 activity. The increase of P and Y in the Beaver Harbour rocks indicates F may have also been an important constituent of metasomatic fluids.