Patterns of larval emergence of capelin (Mallotus villosus) and environmental cues at demersal spawning sites on the northeastern coast of Newfoundland

At spawning beaches in Newfoundland, Canada, capelin ( Mallotus villosus ) larval emergence is triggered by coastal water mass replacement (CWMR). CWMR causes sharp but short increases in temperature in coastal areas by the transport of warm surface water to the coast during onshore wind events. Warm water temperatures stimulate the active emergence of capelin larvae into predator-poor and prey-rich conditions favourable for larval survival. We investigated whether wind events influenced (i) the thermal properties of the water column and (ii) the larval emergence patterns at five demersal (deep-water) spawning sites on the northeastern coast of Newfoundland during the posthatch periods in 2004–2006. Winds oriented along the shore caused frequent and sharp increases in bottom temperature at all sites but did not appear to stimulate the release of larvae into the water column. Instead, peaks in larval densities corresponded to predicted peaks in hatching. Because of this and the presence of recently hatched larvae (3–5 mm) primarily in good condition, we hypothesize that larvae simply emerged from the sediment upon hatching at these demersal spawning sites. We conclude that patterns of larval emergence at demersal sites in this region are different from those reported for the beach in other regions of Newfoundland.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-028 ◽

1981 ◽

Vol 38 (2) ◽

pp. 215-223 ◽

Cited By ~ 57

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

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Lack of genetic divergence in capelin (Mallotus villosus) spawning at beach versus subtidal habitats in coastal embayments of Newfoundland

Canadian Journal of Zoology ◽

10.1139/cjz-2013-0261 ◽

2014 ◽

Vol 92 (5) ◽

pp. 377-382 ◽

Cited By ~ 10

Author(s):

Paulette M. Penton ◽

Craig T. McFarlane ◽

Erin K. Spice ◽

Margaret F. Docker ◽

Gail K. Davoren

Keyword(s):

Local Adaptation ◽

Genetic Divergence ◽

Geographic Area ◽

Mallotus Villosus ◽

The North ◽

Coastal Embayments ◽

Fish Spawning ◽

Capelin Mallotus Villosus ◽

Unpredictable Environment ◽

Spawning Sites

Capelin (Mallotus villosus (Müller, 1776)), a focal forage fish in the north Atlantic, spawn on both beach and demersal (deep-water) sites throughout their circumpolar distribution. Although these habitats rarely occur in close proximity, demersal spawning sites within 4 km of beach spawning sites (subtidal) have recently been discovered in two coastal embayments in Newfoundland, Canada. The physical environment differs considerably between beach and subtidal spawning sites, creating the potential for local adaptation and genetic divergence of capelin from the two habitats, but this has never been investigated on a fine spatial scale. We use eight microsatellite loci to test for genetic divergence between capelin spawning at beach and subtidal sites within these two coastal regions in Newfoundland. We found no genetic differentiation between fish spawning at beach and subtidal sites or between the two regions. The results from this fine-scale study are in agreement with the lack of habitat-based structure reported in other studies examining beach and demersal sites separated by a larger geographic area. We suggest that instead of showing site fidelity and local adaptation, the facultative use of alternate spawning habitats may be a more successful strategy in an unpredictable environment.

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Shoal behaviour and maturity relations of spawning capelin (Mallotus villosus) off Newfoundland: demersal spawning and diel vertical movement patterns

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-204 ◽

2006 ◽

Vol 63 (2) ◽

pp. 268-284 ◽

Cited By ~ 49

Author(s):

Gail K Davoren ◽

John T Anderson ◽

William A Montevecchi

Keyword(s):

Surface Water ◽

Deep Water ◽

Movement Patterns ◽

Gonadal Development ◽

Vertical Movement ◽

Suitable Habitat ◽

Mallotus Villosus ◽

Growth And Survival ◽

Capelin Mallotus Villosus ◽

Warm Surface Water

We investigated shoals of capelin (Mallotus villosus), the focal forage fish species in the Northwest Atlantic, in nearshore Newfoundland during spawning (20002003). Large shoals of maturing capelin were observed in warm (>0 °C), deep (>240 m) water. Smaller shoals of maturing fish were located in two specific areas closer to shore in shallower water (100150 m). Shoals persisted in these staging areas in all years and moved into warm surface water during dark but remained in cold (<0 °C) deep water during daylight. These diel vertical movement patterns may reflect a trade-off between growth and survival, whereby cold, deep water allows reduced predation risk from visual, air-breathing predators while warm, surface water allows increased gonadal development. Shoals of spent capelin, mainly females, were also found in these areas. Sex-specific shoals were observed between staging areas and the coast. Closer to shore, mature, mixed-sex shoals revealed two previously undocumented demersal spawning sites (2833 m). Suitable habitat for spawning and staging areas resulted in persistent aggregations of capelin shoals, reflecting key foraging areas for top predators and critical areas for conservation.

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Patterns of Larval Emergence and Their Potential Impact on Stock Differentiation in Beach Spawning Capelin (Mallotus villosus)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-157 ◽

1987 ◽

Vol 44 (7) ◽

pp. 1326-1336 ◽

Cited By ~ 4

Author(s):

Louis Fortier ◽

William C. Leggett ◽

Serge Gosselin

Keyword(s):

Dark Phase ◽

Mallotus Villosus ◽

Lawrence Estuary ◽

Larval Stages ◽

Abrupt Changes ◽

Capelin Mallotus Villosus ◽

Larval Emergence ◽

Laboratory Emergence ◽

St Lawrence Estuary ◽

Stock Differentiation

The environmental cues triggering larval capelin (Mallotus villosus) emergence in the St. Lawrence estuary and in coastal Newfoundland are different. In the estuary, emergence from the intertidal and subtidal spawning grounds starts with dusk and ends with dawn, indicating an active response to low light intensity. In the laboratory, emergence from undisturbed sediments collected in the field is perfectly synchronized with the dark phase of the illumination cycle. Nocturnal emergence would represent an adaptation reducing vulnerability to visual predators. Previous work has shown that in Newfoundland, capelin emergence from intertidal beaches is triggered by abrupt changes in water temperature following the sporadic advection to the coast of surface water masses characterized by low predator and high prey abundances. We argue that regional differences in the emergence pattern of the species represent different strategies to avoid predation at the onset of the planktonic drift when the vulnerable yolk sac larvae are densely aggregated. Selection acting on the behaviour of the early larval stages could contribute to stock differentiation in capelin.

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Spatial and temporal patterns of capelin (Mallotus villosus) spawning sites in the Barents Sea

Fisheries Research ◽

10.1016/j.fishres.2021.106117 ◽

2021 ◽

Vol 244 ◽

pp. 106117

Author(s):

Salah Alrabeei ◽

Sam Subbey ◽

Sofie Gundersen ◽

Harald Gjøsæter

Keyword(s):

Barents Sea ◽

Temporal Patterns ◽

Spatial And Temporal Patterns ◽

Mallotus Villosus ◽

The Barents Sea ◽

Capelin Mallotus Villosus ◽

Spawning Sites

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Selective Exploitation of Capelin (Mallotus villosus) Eggs by Winter Flounder (Pseudopleuronectes americanus): Capelin Egg Mortality Rates, and Contribution of Egg Energy to the Annual Growth of Flounder

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f84-158 ◽

1984 ◽

Vol 41 (9) ◽

pp. 1294-1302 ◽

Cited By ~ 16

Author(s):

K. T. Frank ◽

W. C. Leggett

Keyword(s):

Average Energy ◽

Winter Flounder ◽

Annual Growth ◽

Pseudopleuronectes Americanus ◽

Mallotus Villosus ◽

Egg Mortality ◽

Capelin Mallotus Villosus ◽

Gonad Production ◽

Conception Bay ◽

Spawning Sites

The consequences of winter flounder (Pseudopleuronectes americanus) predation on capelin (Mallotus villosus) eggs, both in terms of the egg mortality and of the contribution of energy ingested to the annual growth of flounder, were investigated at Bryant's Cove, Conception Bay, Newfoundland. Flounder density in the nearshore area adjacent to the capelin spawning beach increased sharply in each of the three study years in response to the presence of spawning capelin and to the density of capelin eggs on the spawning beaches. Capelin eggs were the dominant item inthedietofwinterflounder14–34 cm TL, averaging 59% by weight. Flounder [Formula: see text] fed less heavily on capelin eggs (22% of food consumed by weight) but because of their larger size and ration were an important source of predation. Egg mortality due to flounder predation was estimated to average 5.0, 2.2, and 1.9% in 1978, 1979, and 1980, respectively. Egg mortality due to predation is believed to be significantly greater at deepwater demersal spawning sites and may have a significant impact on recruitment in demersal spawners. The average energy gain to winter flounder resulting from consumption of capelin eggs was estimated to contribute 23% of the annual growth of flounder in the region (approximate 95% confidence interval: 10–40%). Selective exploitation of capelin eggs by postspawning flounder may also contribute significantly to the rapid recovery of body condition following the extensive depletion of tissue resources due to winter fasting, gonad production, and spawning.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f84-141 ◽

1984 ◽

Vol 41 (8) ◽

pp. 1193-1201 ◽

Cited By ~ 65

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.

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Subglacial brine flow and wind-induced internal waves in Lake Bonney, Antarctica

Antarctic Science ◽

10.1017/s0954102020000036 ◽

2020 ◽

Vol 32 (3) ◽

pp. 223-237

Author(s):

Jade P. Lawrence ◽

Peter T. Doran ◽

Luke A. Winslow ◽

John C. Priscu

Keyword(s):

Water Column ◽

Internal Waves ◽

Open Water ◽

Surface Discharge ◽

Katabatic Wind ◽

Neutral Buoyancy ◽

Cold Temperatures ◽

Glacier Terminus ◽

Wind Events ◽

Taylor Glacier

AbstractBrine beneath Taylor Glacier has been proposed to enter the proglacial west lobe of Lake Bonney (WLB) as well as from Blood Falls, a surface discharge point at the Taylor Glacier terminus. The brine strongly influences the geochemistry of the water column of WLB. Year-round measurements from this study are the first to definitively identify brine intrusions from a subglacial entry point into WLB. Furthermore, we excluded input from Blood Falls by focusing on winter dynamics when the absence of an open water moat prevents surface brine entry. Due to the extremely high salinities below the chemocline in WLB, density stratification is dominated by salinity, and temperature can be used as a passive tracer. Cold brine intrusions enter WLB at the glacier face and intrude into the water column at the depth of neutral buoyancy, where they can be identified by anomalously cold temperatures at that depth. High-resolution measurements also reveal under-ice internal waves associated with katabatic wind events, a novel finding that challenges long-held assumptions about the stability of the WLB water column.

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