Survival Value of An Opportunistic Life-stage Transition in Capelin (Mallotus villosus)

1983 ◽  
Vol 40 (9) ◽  
pp. 1442-1448 ◽  
Author(s):  
Kenneth T. Frank ◽  
William C. Leggett
Keyword(s):  
Seed Dormancy ◽  
Mass Exchange ◽  
Water Mass ◽  
Life Stage ◽  
Mallotus Villosus ◽  
Predator Prey ◽  
Beach Sediments ◽  
Capelin Mallotus Villosus ◽  
Stage Transition

We examined the biological basis of the synchrony between the onset of a pelagic existence in beach-spawned capelin (Mallotus villosus) larvae and the unpredictable occurrence of favorable predator–prey conditions caused by onshore winds. Larvae isolated from the in situ beach sediments, but subject to those changes in water mass characteristics as might remain when such water is introduced into an experimental constant-level tank, emerged in synchrony with larvae in situ. This supports the hypothesis that the larval response to wind-induced water-mass exchange is an active one; it represents an adaptation maximizing feeding success and minimizing mortality due to predation. This "opportunistic" life-stage transition has direct parallels in seed dormancy and diapause in insects.

Effects of predation from juvenile herring (Clupea harengus) on mortality rates of capelin (Mallotus villosus) larvae

2009 ◽  
Vol 66 (10) ◽  
pp. 1693-1706 ◽  
Author(s):  
Elvar H. Hallfredsson ◽  
Torstein Pedersen
Keyword(s):  
Barents Sea ◽  
Fish Larvae ◽  
Mortality Rates ◽  
Clupea Harengus ◽  
Mallotus Villosus ◽  
Rate Estimate ◽  
Predator Prey ◽  
The Barents Sea ◽  
Capelin Mallotus Villosus ◽  
Larvae Density

Predation has been suggested as a cause of substantial mortality of fish larvae to the degree that it might influence recruitment. This field-based study concludes that juvenile herring ( Clupea harengus ) as small pelagic predator can significantly affect mortality rates of the planktonic larvae of capelin ( Mallotus villosus ) in the Barents Sea. Surveys were carried out in the summers of 2001 and 2003. In 2001, juvenile herring were widely distributed and overlapped with capelin larvae over a wide area, whereas in 2003, the herring were more aggregated. The study focused on predation in the areas of predator–prey overlap. Capelin larvae were observed in the herring stomachs at 11 of 24 stations and at 8 of 16 stations where herring were caught in 2001 and 2003, respectively. At those stations, an estimated 7.3% and 9.9% of the capelin larvae were eaten by herring per day in 2001 and 2003, respectively. Statistical models revealed that density of capelin larvae and copepods and occurrence of euphausiids in the stomachs affected the number of capelin larvae per predator stomach. A simplified model with only capelin larvae density as predictor was converted to a functional response relationship using an experimentally derived digestion rate estimate for capelin larvae in herring stomachs.

scholarly journals In situ measurements of capelin (Mallotus villosus) target strength in the North Pacific Ocean

2008 ◽  
Vol 66 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Michael A. Guttormsen ◽  
Christopher D. Wilson
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
In Situ Measurements ◽  
Target Strength ◽  
Mallotus Villosus ◽  
The North ◽  
Capelin Mallotus Villosus ◽  
The North Pacific

Abstract Guttormsen, M. A. and Wilson, C. D. 2009. In situ measurements of capelin (Mallotus villosus) target strength in the North Pacific Ocean. – ICES Journal of Marine Science, 66: 258–263. In situ measurements of capelin (Mallotus villosus) target strength (TS) were collected during summer 2001–2003 near Kodiak Island in the Gulf of Alaska, using a calibrated EK500 echosounder with 38 and 120 kHz split-beam transducers. Targets were detected over dispersed, night-time aggregations using standard acoustic methods, then filtered using a quality-control algorithm to reject invalid targets. The 38 kHz-based, fitted model estimate was TS = 20 log10L− 70.3 (r2 = 0.30), where L is total length of fish. Compared with other studies, the TS-fitted model at 38 kHz was similar to that calculated from swimbladder morphology measurements from St Lawrence estuary capelin (TS = 20 log10L− 69.3), but resulted in greater estimates than models based on in situ measurements of capelin TS in the Barents Sea (TS = 19.1 log10L−74.0) and northern Atlantic Ocean (TS = 20 log10L − 73.1). The large intraspecific variability exhibited in the fitted TS – L models for this species suggests the use of TS measurements from the geographic region where the data were collected.

Influence of temperature on size-dependent predation by a fish (Gasterosteus aculeatus) and a jellyfish (Aurelia aurita) on larval capelin (Mallotus villosus)

1997 ◽  
Vol 54 (12) ◽  
pp. 2759-2766 ◽  
Author(s):  
J K Elliott ◽  
W C Leggett
Keyword(s):  
Gasterosteus Aculeatus ◽  
Aurelia Aurita ◽  
Mallotus Villosus ◽  
Selective Predation ◽  
Moon Jellyfish ◽  
Predator Prey ◽  
Size Dependent ◽  
Capelin Mallotus Villosus ◽  
Different Temperatures ◽  
Influence Of Temperature On

We compared the size-dependent mortality patterns of newly emerged larval capelin (Mallotus villosus) at three different temperatures (3, 9, and 15°C) when exposed to predation by threespine stickleback (Gasterosteus aculeatus) and moon jellyfish (Aurelia aurita). Controlled experiments were conducted in both microcosms (38 L) and mesocosms (3100 L). Some temperature-related trends were evident in experiments with sticklebacks, but not with jellyfish. Sticklebacks fed selectively on smaller capelin larvae at 15°C, were nonselective at 9°C, and fed on larger larvae at 3°C. There was no prey size selection by A. aurita at any of the temperatures examined. Our findings support the view that the direction and magnitude of size-selective predation vary depending on the predator-prey assemblage and environmental conditions examined.

Predator Stomachs as Sampling Tools for Prey Distribution: Atlantic Cod (Gadus morhua) and Capelin (Mallotus villosus)

1993 ◽  
Vol 50 (7) ◽  
pp. 1541-1547 ◽  
Author(s):  
Lenore Fahrig ◽  
George R. Lilly ◽  
Daniel S. Miller
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Mallotus Villosus ◽  
Predator Prey ◽  
Prey Distribution ◽  
Capelin Mallotus Villosus ◽  
Negative Effect ◽  
Predator Abundance ◽  
Bottom Depth

We demonstrate a direct relationship between the amount of prey (capelin, Mallotus villosus) in its predators' stomachs (Atlantic cod, Gadus morhua) and the biomass of the prey in the same localities. The relationship at a local scale implies that predator stomach contents can be used to estimate prey distribution. There is no evidence for either (1) a negative effect of local predator abundance on stomach contents (expected if local prey depletion and/or feeding interference occurs when predator density is high) or (2) a negative effect of the amount of other food in cod stomachs on the amount of capelin in the stomachs (expected if prey switching occurs). There is a negative effect of bottom depth on amount of capelin in cod stomachs as expected, since capelin are pelagic and cod are primarily bottom-dwelling, resulting in less vertical overlap between the species in deep water. This type of analysis may be useful in other predator–prey systems. Simultaneous stomach samples and independent biomass estimates of the prey are required, but once the model is built, it permits estimation of prey distribution in places and times when no direct survey of the prey can be done.

Coastal Water Mass Replacement: Its Effect on Zooplankton Dynamics and the Predator–Prey Complex Associated with Larval Capelin (Mallotus villosus)

1982 ◽  
Vol 39 (7) ◽  
pp. 991-1003 ◽  
Author(s):  
Kenneth T. Frank ◽  
William C. Leggett
Keyword(s):  
Water Mass ◽  
Larval Fish ◽  
Size Fraction ◽  
Safe Site ◽  
Mallotus Villosus ◽  
Daily Growth ◽  
First Feeding ◽  
Capelin Mallotus Villosus ◽  
Zooplankton Dynamics ◽  
Site Water

We examined the hypothesis that the onshore wind-regulated initiation of larval emergence and drift in capelin (Mallotus villosus) was adaptive. Onshore winds were found to induce rapid water mass exchange in coastal Newfoundland resulting in the replacement of cold, high-saline, predator-laden waters with warmer, less-saline waters in which the abundance of an important fraction of the predator community was reduced 3- to 20-fold and zooplankton densities in the edible size fraction were increased 2- to 3-fold. In situ enclosure experiments indicate that the synchronous emergence of larval capelin during onshore winds, coupled with the reduced predator density at this time, results in predator satiation. Wind-induced elevations of the biomass of the edible zooplankton size fraction can produce fivefold increases in the daily growth rate of larval capelin. Capelin larvae thus initiate their drift and first feeding in a wind-induced "safe site." The abundance of eggs and larvae of 11 other marine fish species were also found to be associated with this "safe site" water mass.Key words: capelin, Mallotus villosus; water mass replacement, predation, feeding, growth, larval fish, survival, wind effects, drift, dispersal, enclosures, zooplankton

Multi-environment evaluation of Spanish bunch groundnut genotypes for fresh seed dormancy

2019 ◽  
Vol 79 (3) ◽  
Author(s):  
Narendra Kumar ◽  
B. C. Ajay ◽  
A. L. Rathnakumar ◽  
T. . Radhakrishnan ◽  
M. C. Dagla1 ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Stability Index ◽  
Pooled Analysis ◽  
Genetic Stock ◽  
Breeding Lines ◽  
Fresh Seed ◽  
Differential Behavior ◽  
Environmental Interactions ◽  
Crop Maturity

The present study was carried out to evaluate eight promising Spanish bunch groundnut genotypes during four consecutive year (2014, 2015, 2016, 2017) to study genotype × environmental interactions and to identify stable sources of fresh seed dormancy in Spanish background in groundnut. Pooled analysis of variance revealed highly significant differences among the genotypes and genotype × environmental interactions for fresh seed dormancy at weekly intervals indicating that differential behavior of genotypes for fresh seed dormancy over the environmental conditions. Based on the results of intensity and duration of dormancy and germination stability index, identified four stable advanced breeding lines viz., PBS 12192, PBS 12187, PBS 12191 and PBS 12190 having high fresh seed dormancy of three week and two stable advanced breeding lines viz., PBS 12189 and PBS 12171 having high fresh seed dormancy of two week. Therefore, these genotypes can be used as novel genetic stock of fresh seed dormancy in Spanish bunch and they can be integrated into breeding programs to develop high yielding Spanish bunch cultivars with 2-3 weeks of fresh seed dormancy to avoid yield losses due to in-situ germination at the time of crop maturity.

scholarly journals Latest Miocene restriction of the Mediterranean Outflow Water: a perspective from the Gulf of Cádiz

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Zhi Lin Ng ◽  
F. Javier Hernández-Molina ◽  
Débora Duarte ◽  
Francisco J. Sierro ◽  
Santiago Ledesma ◽  
...  
Keyword(s):  
Mass Exchange ◽  
Water Mass ◽  
Atlantic Water ◽  
Meridional Overturning Circulation ◽  
Gulf Of Cadiz ◽  
Mediterranean Outflow Water ◽  
Gulf Of Cádiz ◽  
Mediterranean Outflow ◽  
The Mediterranean ◽  
Water Mass Exchange

AbstractThe Mediterranean-Atlantic water mass exchange provides the ideal setting for deciphering the role of gateway evolution in ocean circulation. However, the dynamics of Mediterranean Outflow Water (MOW) during the closure of the Late Miocene Mediterranean-Atlantic gateways are poorly understood. Here, we define the sedimentary evolution of Neogene basins from the Gulf of Cádiz to the West Iberian margin to investigate MOW circulation during the latest Miocene. Seismic interpretation highlights a middle to upper Messinian seismic unit of transparent facies, whose base predates the onset of the Messinian salinity crisis (MSC). Its facies and distribution imply a predominantly hemipelagic environment along the Atlantic margins, suggesting an absence or intermittence of MOW preceding evaporite precipitation in the Mediterranean, simultaneous to progressive gateway restriction. The removal of MOW from the Mediterranean-Atlantic water mass exchange reorganized the Atlantic water masses and is correlated to a severe weakening of the Atlantic Meridional Overturning Circulation (AMOC) and a period of further cooling in the North Atlantic during the latest Miocene.

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
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