Capelin (Mallotus villosus) Spawning on the Southeast Shoal: Influence of Physical Factors Past and Present

1989 ◽  
Vol 46 (10) ◽  
pp. 1743-1754 ◽  
Author(s):  
J. E. Carscadden ◽  
K. T. Frank ◽  
D. S. Miller
Keyword(s):  
Surf Zone ◽  
Biological Data ◽  
Published Data ◽  
Physical Factors ◽  
Bottom Temperature ◽  
Mallotus Villosus ◽  
Term Survival ◽  
Grand Banks ◽  
Spawning Stock ◽  
Capelin Mallotus Villosus

Co-occurrence of beach- and offshore bottom-spawning populations of capelin (Mallotus villosus) in the Northwest Atlantic appears to be unusual. To explain the evolution of bottom-spawning in the offshore spawning population on the Southeast Shoal, we examined relevant substrate, water temperature, and biological data. Published data indicate that the Southeast Shoal was not glaciated during the Wisconsin glaciation (about 20 000 yr ago) and was above sea level. As the glaciers melted, this area was a surf zone before it became inundated. This suggests that this stock was once a beach-spawning stock and supports our hypothesis that substrate is the ultimate factor affecting spawning location. Analysis of 7 yr of distribution, maturity, and bottom temperature data showed that the variation in the final spawning location was not large and spawning occurred where bottom temperatures exceeded approximately 2 °C. We conclude that bottom temperature is a proximate factor influencing the final spawning location. Physical data for other areas of the Grand Banks indicate that only the Southeast Shoal has favourable substrate, bottom temperatures and environmental factors subsequent to spawning to allow the long-term survival of a capelin population.

Interactions multispécifiques: répartition spatio-temporelle des larves de capelan (Mallotus villosus), d'éperlan (Osmerus mordax) et de hareng de l'Atlantique (Clupea harengus harengus) an sein de la communauté planctonique de l'estuaire moyen du Saint-Laurent

1982 ◽  
Vol 39 (8) ◽  
pp. 1164-1174 ◽  
Author(s):  
R. Courtois ◽  
M. Simoneau ◽  
J. J. Dodson
Keyword(s):  
Fish Larvae ◽  
Clupea Harengus ◽  
Temporal Organization ◽  
Physical Factors ◽  
Osmerus Mordax ◽  
Mallotus Villosus ◽  
Saint Lawrence River ◽  
Capelin Mallotus Villosus ◽  
Clupea Harengus Harengus ◽  
Species Specific

The study of the spatial and temporal organization of the planktonic community of the middle estuary of the Saint Lawrence River revealed that fish larvae were distributed in such a way as to minimize interactions between species. Smelt (Osmerus mordax) larvae were distributed upstream whereas capelin (Mallotus villosus) and Atlantic herring (Clupea harengus harengus) larvae were found downstream in June 1979. Capelin larvae were more abundant at the surface (0–20 m) whereas herring larvae were concentrated in deeper waters (20–60 m). The ecological separation observed was maintained by multiple physical factors and appeared to be the consequence of species-specific reproductive strategies. The abundance of chaetognaths, euphausiids, and amphipods in deeper waters suggests that these forms could be important predators of fish larvae. Herring larvae may be particularly vulnerable because of their distribution in deep water. Capelin larvae which are very abundant in June could also be vulnerable to predation during the diurnal migrations of the macroplankton. Smelt larvae appear to be little affected by predation from these forms as a result of their distribution in fresher waters.

Advection–Diffusion Modelling of Larval Capelin (Mallotus villosus) Dispersion in Conception Bay, Newfoundland

1994 ◽  
Vol 51 (6) ◽  
pp. 1297-1307 ◽  
Author(s):  
Brad deYoung ◽  
John Anderson ◽  
Richard J. Greatbatch ◽  
Paul Fardy
Keyword(s):  
Residence Time ◽  
Diagnostic Model ◽  
Physical Factors ◽  
Surface Mixed Layer ◽  
Mallotus Villosus ◽  
Advection Diffusion ◽  
Capelin Mallotus Villosus ◽  
June July ◽  
Release Location ◽  
Conception Bay

A numerical model was used to determine the residence time of capelin (Mallotus villosus) larvae in Conception Bay, Newfoundland. The larvae were observed in the surface mixed layer of the Bay following release from beaches in June–July in order to examine how they move outside the Bay and what physical factors influence their rate of transport. A diagnostic model of Conception Bay provides a fixed velocity field which drives an advection–diffusion model applied to capelin larval dispersal from the Bay. The model was run for different periods to explore dependence of the residence time on different conditions during the period 1989–90. Model results showed that the residence time depends on the release location of the larvae in the Bay. While the residence time of the larvae does vary, we estimate it to be roughly 30 d for larvae released from the head of the Bay. Residence times are much shorter for larvae near the mouth of the Bay.

Utility of Meristic and Morphometric Characters for Identification of Capelin (Mallotus villosus) Stocks in Canadian Atlantic Waters

1978 ◽  
Vol 35 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Joan C. Sharp ◽  
Kenneth W. Able ◽  
William C. Leggett ◽  
James E. Carscadden
Keyword(s):  
Mallotus Villosus ◽  
Meristic Characters ◽  
Body Depth ◽  
Morphometric Characters ◽  
Lawrence Estuary ◽  
Grand Banks ◽  
Capelin Mallotus Villosus ◽  
Statistical Separation ◽  
And Migration ◽  
St Lawrence Estuary

Multivariate discriminant function analyses were performed on 9 morphometric and 11 meristic characters of capelin (Mallotus villosus) samples at Île aux Coudres in the St. Lawrence estuary; Sept Îles, Natashquan, and Grande Rivière in the Gulf of St. Lawrence; Southeast Shoal on the Grand Banks; and Herring Neck, Notre Dame Bay, Newfoundland. Analyses of meristic characters provided no evidence of discrete stocks. Analyses of morphometric characters provided strong statistical separation between areas. A posteriori classification of groups yielded 93.1% correct classification for males and 73.3% for females. Only snout length, eye diameter, head length, and body depth contributed significantly to the separation obtained. These findings suggest that meristic characters offer little potential for stock identification in Canadian Atlantic waters. Morphometric characters may prove useful, but further study, corroborated with life history and migration data, is required to confirm this. Key words: capelin, Mallotus villosus, meristics, morphometrics, stock separation, Gulf of St. Lawrence, Newfoundland, Canadian Atlantic, multivariate analysis

Wind Regulation of Emergence Times and Early Larval Survival in Capelin (Mallotus villosus)

1981 ◽  
Vol 38 (2) ◽  
pp. 215-223 ◽  
Author(s):  
Kenneth T. Frank ◽  
William C. Leggett
Keyword(s):  
Physical Condition ◽  
Population Biology ◽  
Larval Density ◽  
Larval Survival ◽  
Published Data ◽  
Mallotus Villosus ◽  
Good Physical Condition ◽  
Emergence Patterns ◽  
Capelin Mallotus Villosus ◽  
Larval Emergence

Factors regulating the emergence and survival of capelin (Mallotus villosus) larvae from their beach gravel nest sites were investigated in the spring and summer of 1978 and 1979. In both years, the pattern of larval emergence was characterized by intermittent abrupt increases in the numbers of larvae in the nearshore waters and corresponding precipitous declines in the density of preemergent larvae in the beach gravel. Both events were strongly correlated with onshore wind-induced wave action which disturbed the beach. Larval emergence patterns were unrelated to changes in tidal amplitude or day–night variation. The generality of this wind-induced larval emergence hypothesis was tested and confirmed using published data from two separate studies conducted at three different Newfoundland sites during 1927, 1929, 1930, and 1941. The density of larvae in the beach gravel was positively correlated with the length of time separating the occurrence of onshore winds. The result was a pronounced temporal clumping of larvae hatching at different times, periodic releases of large numbers of larvae into the aquatic environment, and a progressive deterioration in the physical condition of larvae emerging as beach residence time increased. The frequency of onshore winds during the hatching period was 50% greater in 1979 relative to 1978. Egg densities were similar in 1978 and 1979 but larval densities (no./m3) in the nearshore environment were 60% greater in 1979. This increase in larval density conformed to the increase in the proportion of larvae exiting the beach in good physical condition in 1979.Key words: capelin, Mallotus villosus; Newfoundland, larval emergence, larval survival, wind, population biology, beach spawning, coastal environments, year-class strength

Meteorological and Hydrographic Regulation of Year-Class Strength in Capelin (Mallotus villosus)

1984 ◽  
Vol 41 (8) ◽  
pp. 1193-1201 ◽  
Author(s):  
W. C. Leggett ◽  
K. T. Frank ◽  
J. E. Carscadden
Keyword(s):  
Swimming Performance ◽  
Abiotic Factors ◽  
Larval Survival ◽  
Critical Periods ◽  
Mallotus Villosus ◽  
Large Spatial Scale ◽  
Spawning Stock ◽  
Class Strength ◽  
Capelin Mallotus Villosus ◽  
Parent Stock

Year-class strength (YCS) in eastern Newfoundland stocks of capelin (Mallotus villosus), a beach spawning osmerid, during the interval 1966–78 was strongly influenced by onshore wind frequency during the period immediately following hatching (WIND) and water temperatures experienced during the subsequent period of larval drift (TEMPSUM). The exact form of the relationship was ln YCS = 16.10 − 0.19WIND + 0.19TEMPSUM, R2 = 0.58. Wind conditions subsequent to hatching are known to influence both the timing of larval emergence from the beach spawning beds and the physical condition of larvae at emergence. Our analysis suggests that the influence of wind on early larval survival is also strong. The role of water temperatures during drift may be indirect, operating via its influence on food production. This could operate by altering mortality rates due to starvation or by altering growth rates which would influence swimming performance, predator avoidance, and time to metamorphosis. The strong influence of these abiotic variables, independent of parent stock size, adds further support to the hypothesis that abiotic factors operating at critical periods in larval development may be more important than spawning stock biomass as regulators of year-class size. Our findings also suggest that these critical periods must be identified and quantified at time scales relevant to individual larvae if reliable forecasting of year-class strength is to be achieved. On the other hand, the large spatial scale of the effects suggests that the space scale of individual larvae is of lesser importance in such analyses.

scholarly journals Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis

2013 ◽  
Vol 71 (4) ◽  
pp. 775-783 ◽  
Author(s):  
Shannon G. Obradovich ◽  
Erin H. Carruthers ◽  
George A. Rose
Keyword(s):  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Mallotus Villosus ◽  
Bottom Up ◽  
Grand Banks ◽  
Capelin Mallotus Villosus ◽  
Dietary Component ◽  
Δ 15N ◽  
Δ15n And Δ13c

Abstract Capelin (Mallotus villosus) is the key forage fish species in the Newfoundland and Labrador Shelf ecosystem. Capelin stocks collapsed in the early 1990s, concurrent with declines in “northern” Atlantic cod, Gadus morhua. Neither has fully recovered yet. Changes in growth, condition, and behaviour accompanied capelin declines on the northern Grand Banks (NGB), and remain two decades later. Feeding, growth, and condition of NGB capelin were all lower when compared with capelin from the eastern Scotian Shelf (ESS), where abundance increased following predator declines. For age 2–5 capelin of both sexes, all but one of five comparable age–sex groups were significantly larger on the ESS (e.g. age 3 females average 169 mm on the ESS and 151 mm on the NGB). Neither temperature nor density-dependence explain these differences. However, dietary differences were prominent. ESS capelin had higher total fullness indices (TFIs) than NGB fish at all sizes [mean TFIESS = 1.43 (± 1.14), mean TFINGB = 0.48 (± 0.70)]. Euphausiids (especially Thysanoessa spp.) were a main dietary component on the ESS but not on the NGB. Stable isotope analyses (δ15N and δ13C) for NGB capelin also indicated few dietary euphausiids. Trophic fractionation of δ 15N was 4.740/00, suggesting NGB capelin were food limited. Capelin recovery on the Newfoundland and Labrador Shelf appears limited by bottom-up forcing, in particular lack of euphausiid prey.

scholarly journals Parenteral Nutrition and Oxidant Load in Neonates

Nutrients ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 2631
Author(s):  
Kandeepan Karthigesu ◽  
Robert F. Bertolo ◽  
Robert J. Brown
Keyword(s):  
Parenteral Nutrition ◽  
Storage Temperature ◽  
Oral Feeding ◽  
Published Data ◽  
Short Term ◽  
Antioxidant Defences ◽  
Term Survival ◽  
Nutrient Sources ◽  
Short Term Survival

Neonates with preterm, gastrointestinal dysfunction and very low birth weights are often intolerant to oral feeding. In such infants, the provision of nutrients via parenteral nutrition (PN) becomes necessary for short-term survival, as well as long-term health. However, the elemental nutrients in PN can be a major source of oxidants due to interactions between nutrients, imbalances of anti- and pro-oxidants, and environmental conditions. Moreover, neonates fed PN are at greater risk of oxidative stress, not only from dietary sources, but also because of immature antioxidant defences. Various interventions can lower the oxidant load in PN, including the supplementation of PN with antioxidant vitamins, glutathione, additional arginine and additional cysteine; reduced levels of pro-oxidant nutrients such as iron; protection from light and oxygen; and proper storage temperature. This narrative review of published data provides insight to oxidant molecules generated in PN, nutrient sources of oxidants, and measures to minimize oxidant levels.

scholarly journals Early life growth is affecting timing of spawning in the semelparous Barents Sea capelin (Mallotus villosus)

2021 ◽  
pp. 102614
Author(s):  
Florian Berg ◽  
Samina Shirajee ◽  
Arild Folkvord ◽  
Jane Aanestad Godiksen ◽  
Georg Skaret ◽  
...  
Keyword(s):  
Early Life ◽  
Barents Sea ◽  
Mallotus Villosus ◽  
Capelin Mallotus Villosus ◽  
Timing Of Spawning

Second Paper: The Effects of Physical Factors on Ignition Delay

1966 ◽  
Vol 181 (1) ◽  
pp. 34-59 ◽  
Author(s):  
W-T. Lyn ◽  
E. Valdmanis
Keyword(s):  
Ignition Delay ◽  
Drop Size ◽  
Injection Rate ◽  
Published Data ◽  
Physical Factors ◽  
Injection Timing ◽  
Air Velocity ◽  
Spray Form ◽  
Temperature And Pressure ◽  
Compression Temperature

The effects of physical factors on ignition delay have been studied on a motored research engine using a single injection technique. The fuels used included a high cetane number reference fuel, gas oil and M.T. 80 petrol. The primary factors investigated are those pertaining to the fuel spray, such as injection timing, quantity, and pressure (affecting drop size, velocity and injection rate); hole diameter (affecting drop size and injection rate) and spray form (nozzle type); and those pertaining to the engine, such as temperature, pressure and air velocity. Engine operating variables such as speed and load affect the ignition delay because they change the primary factors such as injection pressure, compression temperature, pressure and air velocity. It has been found that under normal running conditions, compression temperature and pressure are the major factors. All other factors have only secondary effects. Under starting conditions, when ignition is marginal, mixture formation becomes as important as compression temperature and pressure. Such factors as air velocity and spray form which affect the mixing pattern can have a very pronounced effect on ignition delay. Published data on ignition delay are compared with those obtained in the present investigation and a generalization of the data is recommended for engine design and computational work.

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