Predation by Jellyfish on Larval Fish: An Experimental Evaluation Employing in situ Enclosures

1988 ◽  
Vol 45 (7) ◽  
pp. 1173-1190 ◽  
Author(s):  
Yves de Lafontaine ◽  
W. C. Leggett
Keyword(s):  
Functional Response ◽  
Larval Fish ◽  
Larval Mortality ◽  
Larval Density ◽  
Larval Survival ◽  
Exogenous Feeding ◽  
Larval Size ◽  
Capelin Mallotus Villosus ◽  
Jellyfish Species

Large in situ enclosures were used to investigate the mortality of yolk-sac larval capelin (Mallotus villosus) by four species of jellyfish predators. Daily instantaneous larval mortality increased linearly with predator density but was independent of initial larval density, indicating a linear functional response of the four jellyfish species. The addition of alternative prey did not modify the linearity of the functional response and did not significantly reduce or increase larval mortality imposed by two jellyfish species. The evidence of a linear response in large enclosures contrasts with the curvilinear (Type II) response previously reported in studies conducted in small laboratory containers. Larval mortality was strongly dependent on predator size within jellyfish species and increased with initial larval size. Larval capelin appeared more susceptible to predation at the time of transition from endogenous to exogenous feeding. Daily larval mortality rates due to predation varied between 0.015 and 1.58 depending on jellyfish species and appeared more strongly determined by body mass than differences in feeding appendages of jellyfish. Our results indicate that reduced larval mortality to jellyfish predation is achievable only by timing larval release in water mass where jellyfish numbers are naturally reduced. We estimated that macro invertebrate predation has the potential of being the primary regulator of larval survival and we hypothesized that large intra- and interannual variation in larval survival may be due to the variability in the emergence timing of capelin larvae relative to the growth trajectory of jellyfish.

Effect of Container Size on Estimates of Mortality and Predation Rates in Experiments with Macrozooplankton and Larval Fish

1987 ◽  
Vol 44 (9) ◽  
pp. 1534-1543 ◽  
Author(s):  
Yves De Lafontaine ◽  
William C. Leggett
Keyword(s):  
Larval Fish ◽  
Larval Mortality ◽  
Larval Density ◽  
Predation Rate ◽  
Mortality Rates ◽  
Laboratory Studies ◽  
Larval Size ◽  
Capelin Mallotus Villosus ◽  
Order Of Magnitude

We investigated the effect of container size on the predation rate of the jellyfish Aurelia aurita on postemergent capelin (Mallotus villosus) larvae in large in situ cylindrical enclosures. Total depth of the enclosures varied between 1 and 9 m and yielded volumes that ranged from 0.26 to 6.35 m3. Instantaneous mortality rates of capelin larvae due to jellyfish predation varied inversely and nonlinearly with the volume of the enclosure. Over the range of container sizes used, mortality rates differed by one order of magnitude. Container volume explained 80% of the variance in mortality rates, while predator size and larval size accounted for 8.3 and 2.3% of the variability, respectively. Mortality rate was independent of the initial larval density within each container size. Differences in mortality rates among container sizes are explained by the observed differences in the vertical patchiness of larvae among various enclosure sizes. These findings indicate that experiments conducted in small containers typical of those used in laboratory studies seriously overestimate rates of larval mortality due to predation. Direct extrapolation of the results of such laboratory studies to field conditions is therefore not warranted. We conclude that the vertical distributions of predator and prey may be the most important factor controlling predator–prey relationships in situ.

Evaluation of in situ Enclosures for Larval Fish Studies

1987 ◽  
Vol 44 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Yves de Lafontaine ◽  
William C. Leggett
Keyword(s):  
Larval Fish ◽  
Fish Larvae ◽  
Low Cost ◽  
Experimental Studies ◽  
Size Composition ◽  
Surrounding Water ◽  
Larval Fishes ◽  
Plastic Bags ◽  
Capelin Mallotus Villosus

Two in situ enclosure designs intended for use in larval fish studies were evaluated for their capability to reproduce and track the physical properties of the surrounding water and to maintain the behavioral characteristics of enclosed organisms. The enclosures, which were constructed of porous material, allowed near instantaneous response to natural variations in temperature, salinity, and dissolved oxygen at all depths. Phytoplankton biomass inside the enclosures was less variable than that observed outside and its size composition was related to the porosity of the material used. Particle sinking rates inside the enclosures were much lower than those previously reported for plastic bags, suggesting a higher degree of turbulence in our enclosures. Newly hatched larval capelin (Mallotus villosus) and Zooplankton stocked into the enclosures exhibited diel migration of amplitude similar to that observed in the field. Zooplankton were more homogeneously distributed than fish larvae although heterogeneity decreased at night for both taxa. Low cost, ease of handling, environmental reproducibility, and quality of replication provided by the enclosures make them particularly appropriate for replicated experimental studies of the interactions between larval fishes, their predators, and prey.

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

scholarly journals Larval Size and Recruitment Mechanisms in Fishes: Toward a Conceptual Framework

1988 ◽  
Vol 45 (9) ◽  
pp. 1657-1670 ◽  
Author(s):  
Thomas J. Miller ◽  
Larry B. Crowder ◽  
James A. Rice ◽  
Elizabeth A. Marschall
Keyword(s):  
Body Size ◽  
Conceptual Framework ◽  
Larval Fish ◽  
Larval Growth ◽  
Larval Survival ◽  
Freshwater Species ◽  
Larval Size ◽  
Growth And Survival ◽  
Fisheries Science ◽  
Risk Of Predation

Understanding the mechanisms controlling recruitment in fishes is a major problem in fisheries science. Although the literature on recruitment mechanisms is large and growing rapidly, it is primarily species specific. There is no conceptual framework to integrate the existing information on larval fish ecology and its relationship to survival and recruitment. In this paper, we propose an integrating framework based on body size. Although all larval fish are small relative to adult fish, total length at hatching differs among species by an order of magnitude. As many of the factors critical to larval survival and growth are size dependent, substantially different expectations arise about which mechanisms might be most important to recruitment success. We examined the evidence for the importance of size to feeding and starvation, to activity and searching ability, and to risk of predation. Regressions based on data from 72 species of marine and freshwater species suggest that body size is an important factor that unifies many of the published observations. A conceptual framework based on body size has the potential to provide a useful integration of the available data on larval growth and survival and a focus for future studies of recruitment dynamics.

Climate-associated trends and variability in ichthyoplankton phenology from the longest continuous larval fish time series on the east coast of the United States

2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch
Keyword(s):  
United States ◽  
Environmental Variability ◽  
Larval Fish ◽  
Interspecific Interactions ◽  
River Estuary ◽  
Atlantic Multidecadal Oscillation ◽  
The United States ◽  
Larval Survival ◽  
Ecological Communities ◽  
Northerly Wind

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.

Functional response of Fucus vesiculosus communities to tributyltin measured in an in situ continuous flow-through system

Hydrobiologia ◽  
1989 ◽  
Vol 188-189 (1) ◽  
pp. 277-283 ◽  
Author(s):  
C. Lindblad ◽  
U. Kautsky ◽  
C. André ◽  
N. Kautsky ◽  
M. Tedengren
Keyword(s):  
Functional Response ◽  
Continuous Flow ◽  
Fucus Vesiculosus ◽  
Flow Through

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

scholarly journals Density and body size of the larval stages of the invasive golden mussel (Limnoperna fortunei) in two neotropical rivers

2012 ◽  
Vol 23 (3) ◽  
pp. 282-292 ◽  
Author(s):  
Vivianne Eilers ◽  
Márcia Divina de Oliveira ◽  
Kennedy Francis Roche
Keyword(s):  
Body Size ◽  
Larval Stage ◽  
Larval Density ◽  
Limnoperna Fortunei ◽  
Larval Size ◽  
Larval Stages ◽  
Positive Effects ◽  
Paraguay River ◽  
Body Sizes ◽  
Golden Mussel

AIM: The present study involved an analysis of the monthly variations in the population densities and body sizes of the different stages of planktonic larvae of the invasive golden mussel (Limnoperna fortunei), in the rivers Paraguay and Miranda; METHODS: The study was carried out between February 2004 and January 2005. Monthly collection of the plankton samples was accompanied by physical, chemical and biological analyses of the water; RESULTS: The Miranda River presented higher values of calcium, pH, alkalinity, conductivity and total phosphorous. Larval density varied from 0-24 individuals.L-1 in the Paraguay River, with a peak in March of 2004, while in the Miranda River, densities varied between 0-9 individuals.L-1 with a peak in February of 2004. No larvae were encountered during the coldest months, May and June. No significant correlations were found between environmental variables and larval density in either river. Only the valved larval stages were recorded. The "D" and veliger forms were most abundant; umbonate larvae were rare in the Miranda River samples. Mean body sizes of "D", veliger and umbonate larval stages were, respectively, 111, 135 and 152 µm, in the Paraguay River, and 112, 134 and 154 µm in the Miranda River. Principal Components Analysis indicated positive relationships between "D" larval stage size and the ratio between inorganic and organic suspended solids, while negative relationships were found between larval size and calcium and chlorophyll-<img border=0 width=7 height=8 src="/img/revistas/alb/2012nahead/ALB_AOP_230307car01.jpg">; CONCLUSIONS: The larvae were recorded in the plankton during most of the year, with the exception of the two colder months. Neither densities nor larval stage body sizes were significantly different between the two rivers. Possible positive effects of food and calcium concentrations on body size were not recorded. This species may be adapted to grow in environments with elevated sediment concentrations.

scholarly journals A Process for Evaluating Adverse Environmental Impacts by Cooling-Water System Entrainment at a California Power Plant

2002 ◽  
Vol 2 ◽  
pp. 81-105 ◽  
Author(s):  
C.P. Ehrler ◽  
J.R. Steinbeck ◽  
E.A. Laman ◽  
J.B. Hedgepeth ◽  
J.R. Skalski ◽  
...  
Keyword(s):  
Power Plant ◽  
Environmental Impacts ◽  
Environmental Protection Agency ◽  
Transport Model ◽  
Larval Fish ◽  
Larval Mortality ◽  
Water System ◽  
Cooling Water ◽  
Water Quality Control ◽  
Plant Effects

A study to determine the effects of entrainment by the Diablo Canyon Power Plant (DCPP) was conducted between 1996 and 1999 as required under Section 316(b) of the Clean Water Act. The goal of this study was to present the U.S. Environmental Protection Agency (EPA) and Central Coast Regional Water Quality Control Board (CCRWQCB) with results that could be used to determine if any adverse environmental impacts (AEIs) were caused by the operation of the plant’s cooling-water intake structure (CWIS). To this end we chose, under guidance of the CCRWQCB and their entrainment technical working group, a unique approach combining three different models for estimating power plant effects: fecundity hindcasting (FH), adult equivalent loss (AEL), and the empirical transport model (ETM). Comparisons of the results from these three approaches provided us a relative measure of confidence in our estimates of effects. A total of 14 target larval fish taxa were assessed as part of the DCPP 316(b). Example results are presented here for the kelp, gopher, and black-and-yellow (KGB) rockfish complex and clinid kelpfish. Estimates of larval entrainment losses for KGB rockfish were in close agreement (FH is approximately equals to 550 adult females per year, AEL is approximately equals to 1,000 adults [male and female] per year, and ETM = larval mortality as high as 5% which could be interpreted as ca. 2,600 1 kg adult fish). The similar results from the three models provided confidence in the estimated effects for this group. Due to lack of life history information needed to parameterize the FH and AEL models, effects on clinid kelpfish could only be assessed using the ETM model. Results from this model plus ancillary information about local populations of adult kelpfish suggest that the CWIS might be causing an AEI in the vicinity of DCPP.

scholarly journals Effectiveness of Diflubenzuron and Bacillus thuringiensis Against Gypsy Moth Populations

1997 ◽  
Vol 14 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Kevin W. Thorpe ◽  
Richard L. Ridgway ◽  
Ralph E. Webb
Keyword(s):  
Bacillus Thuringiensis ◽  
Population Density ◽  
Gypsy Moth ◽  
Mass Density ◽  
Larval Mortality ◽  
Larval Density ◽  
Egg Mass ◽  
Percent Reduction ◽  
Moth Population ◽  
Oak Trees

Abstract Aerial applications of Bacillus thuringiensis Berliner subsp. kurstaki (74.1 billion international units/ha per application; single and double applications), diflubenzuron [69 g (ai)/ha], and no treatment were evaluated. Treatment effects were estimated from frass collections, defoliation, counts of pupae under burlap, and egg-mass counts. Estimates of larval density in the canopy 20 days after treatment ranged from 318.3 to 55.5 larvae per m² in the control- and diflubenzuron-treated plots, respectively. Larval density was reduced in all treatments, and was lowest in the plots treated with diflubenzuron and two applications of B. thuringiensis. Population density rapidly declined in the control plots, and by June 20, when larvae were predominantly in the fifth and sixth instars, no significant differences in larval density were detected among the treatments. Significantly less defoliation occurred to oak trees in the treated plots, but no differences were detected among the spray treatments. Counts of pupae under burlap, postseason egg-mass counts, and percent reduction in egg-mass density did not differ significantly among treatments or versus controls. These results suggest that diflubenzuron and double B. thuringiensis treatments caused higher levels of larval mortality than occurred with a single B. thuringiensis application, but that with a naturally declining gypsy moth population the final levels of damage were the same under all treatments. North. J. Appl. 14(3):135-140.

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