scholarly journals Surface slicks are pelagic nurseries for diverse ocean fauna

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan L. Whitney ◽  
Jamison M. Gove ◽  
Margaret A. McManus ◽  
Katharine A. Smith ◽  
Joey Lecky ◽  
...  
Keyword(s):  
Larval Fish ◽  
Marine Animals ◽  
Larval Phase ◽  
Larval Fishes ◽  
Organic Debris ◽  
Pelagic Environment ◽  
Marine Larvae ◽  
Tightly Coupled ◽  
Surface Dwelling ◽  
Water Ecosystems

AbstractMost marine animals have a pelagic larval phase that develops in the coastal or open ocean. The fate of larvae has profound effects on replenishment of marine populations that are critical for human and ecosystem health. Larval ecology is expected to be tightly coupled to oceanic features, but for most taxa we know little about the interactions between larvae and the pelagic environment. Here, we provide evidence that surface slicks, a common coastal convergence feature, provide nursery habitat for diverse marine larvae, including > 100 species of commercially and ecologically important fishes. The vast majority of invertebrate and larval fish taxa sampled had mean densities 2–110 times higher in slicks than in ambient water. Combining in-situ surveys with remote sensing, we estimate that slicks contain 39% of neustonic larval fishes, 26% of surface-dwelling zooplankton (prey), and 75% of floating organic debris (shelter) in our 1000 km2 study area in Hawai‘i. Results indicate late-larval fishes actively select slick habitats to capitalize on concentrations of diverse prey and shelter. By providing these survival advantages, surface slicks enhance larval supply and replenishment of adult populations from coral reef, epipelagic, and deep-water ecosystems. Our findings suggest that slicks play a critically important role in enhancing productivity in tropical marine ecosystems.

scholarly journals CRISPR/CAS9 mutagenesis of a single r-opsin gene blocks phototaxis in a marine larva

2019 ◽  
Vol 286 (1904) ◽  
pp. 20182491 ◽  
Author(s):  
S. Neal ◽  
D. M. de Jong ◽  
E. C. Seaver
Keyword(s):  
Gene Editing ◽  
Pigment Cell ◽  
Polymerase Chain Reaction Amplification ◽  
Photoreceptor Cells ◽  
Opsin Gene ◽  
Suitable Habitat ◽  
Marine Animals ◽  
Light Detection ◽  
Larval Phase ◽  
Spatio Temporal

Many marine animals depend upon a larval phase of their life cycle to locate suitable habitat, and larvae use light detection to influence swimming behaviour and dispersal. Light detection is mediated by the opsin genes, which encode light-sensitive transmembrane proteins. Previous studies suggest that r-opsins in the eyes mediate locomotory behaviour in marine protostomes, but few have provided direct evidence through gene mutagenesis. Larvae of the marine annelid Capitella teleta have simple eyespots and are positively phototactic, although the molecular components that mediate this behaviour are unknown. Here, we characterize the spatio-temporal expression of the rhabdomeric opsin genes in C. teleta and show that a single rhabdomeric opsin gene, Ct-r-opsin1 , is expressed in the larval photoreceptor cells. To investigate its function, Ct-r-opsin1 was disrupted using CRISPR/CAS9 mutagenesis. Polymerase chain reaction amplification and DNA sequencing demonstrated efficient editing of the Ct-r-opsin1 locus. In addition, the pattern of Ct-r-opsin1 expression in photoreceptor cells was altered. Notably, there was a significant decrease in larval phototaxis, although the eyespot photoreceptor cell and associated pigment cell formed normally and persisted in Ct-r-opsin1 -mutant animals. The loss of phototaxis owing to mutations in Ct-r-opsin1 is similar to that observed when the entire photoreceptor and pigment cell are deleted, demonstrating that a single r-opsin gene is sufficient to mediate phototaxis in C. teleta . These results establish the feasibility of gene editing in animals like C. teleta , and extend previous work on the development, evolution and function of the C. teleta visual system . Our study represents one example of disruption of animal behaviour by gene editing through CRISPR/CAS9 mutagenesis, and has broad implications for performing genome editing studies in a wide variety of other understudied animals.

Larval nurseryfish, Kurtus gulliveri (Perciformes : Kurtidae), in the Adelaide River of the Northern Territory: their season, fellow travellers and unusual rib anatomy

2016 ◽  
Vol 64 (4) ◽  
pp. 262 ◽  
Author(s):  
Tim M. Berra ◽  
Dion Wedd ◽  
You He
Keyword(s):  
Larval Fish ◽  
Three Dimensional ◽  
Northern Territory ◽  
Spawning Season ◽  
Swim Bladder ◽  
Northern Australia ◽  
Computerised Tomography ◽  
Larval Fishes ◽  
Big Picture ◽  
Unique Method

This study was undertaken to determine the spawning season of the nurseryfish, a species with a unique method of parental care found only in northern Australia and southern New Guinea. Monthly samplings with an ichthyoplankton net at the same locality in the Adelaide River over multiple years yielded no larval nurseryfish in February, March, April and May. Larvae first appeared in June and were collected each month until January. From this we conclude that the nurseryfish spawning season in the Adelaide River is June–January. Twelve other larval fish species from 10 families were collected in the plankton tows with nurseryfish. Larval nurseryfish are readily identified and separated from other larval fishes by their peculiar rib anatomy, an important diagnostic character of Kurtus. The development of the unusual rib anatomy is examined with three-dimensional micro-computerised tomography scans of 12–21-mm standard length (SL) specimens. The bony protection of the swim bladder formed by the ribs is visible in the smallest postflexion specimens examined and is essentially complete by 19 mm SL. These ecological and anatomical observations add another pixel to the big picture of nurseryfish life history.

scholarly journals Effects of Microplastics on the Feeding Rates of Larvae of a Coastal Fish: Direct Consumption, Trophic Transfer, and Effects on Growth and Survival

2021 ◽  
Author(s):  
Christine Uy ◽  
Darren Johnson
Keyword(s):  
Larval Fish ◽  
Trophic Transfer ◽  
Control Group ◽  
Feeding Rates ◽  
Lower Growth ◽  
Larval Phase ◽  
Coastal Fish ◽  
Growth And Survival ◽  
Low Concentrations ◽  
High Concentrations

Abstract Microplastics are now found throughout the world’s oceans, and although many organisms ingest microplastics, less is known about how plastics in seawater may affect key processes such as feeding rate, growth, and survival. We used a series of laboratory experiments to test whether microplastics in seawater affected the feeding rates of larvae of the California Grunion, Leuresthes tenuis. In addition, we tested whether trophic transfer of microplastics from zooplankton to larval fish can occur and affect growth and survival of fish. We measured feeding rates of grunion larvae at various concentrations of 75–90 µm and 125–250 µm polyethylene microplastics and under both still water and turbulent conditions. In these experiments, exposure to microplastics had modest effects on feeding rates, though responses may be somewhat complex. Low concentrations of microplastics increased feeding rates compared to the control, but at higher concentrations, feeding rates were indistinguishable from those in the control group though effects were small compared to natural variation in feeding rates among individual fish. Experiments to test for trophic transfer of microplastics revealed that grunion larvae that were fed brine shrimp exposed to high concentrations of microplastics had lower growth rates and elevated mortality rates. Overall, our results suggest that the direct effects of microplastics on feeding rates of California Grunion during the early larval phase are minor, while the trophic transfer of microplastics from zooplankton to larval fish may have significant effects on their growth and survival.

scholarly journals Hydrodynamic regime drives flow reversals in suction feeding larval fishes during early ontogeny

2019 ◽  
Author(s):  
Krishnamoorthy Krishnan ◽  
Asif Shahriar Nafi ◽  
Roi Gurka ◽  
Roi Holzman
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
Prey Capture ◽  
Sparus Aurata ◽  
Larval Fish ◽  
Fish Larvae ◽  
Numerical Models ◽  
Hydrodynamic Regime ◽  
Suction Feeding ◽  
Larval Fishes

AbstractFish larvae are the smallest self-sustaining vertebrates. As such, they face multiple challenge that stem from their minute size, and from the hydrodynamic regime in which they dwell. This regime of intermediate Reynolds numbers (Re) was shown to affect the swimming of larval fish and impede their ability to capture prey. Numerical simulations indicate that the flow fields external to the mouth in younger larvae result in shallower spatial gradients, limiting the force exerted on the prey. However, observations on feeding larvae suggest that failures in prey capture can also occur during prey transport, although the mechanism causing these failures is unclear. We combine high-speed videography and numerical simulations to investigate the hydrodynamic mechanisms that impede prey transport in larval fishes. Detailed kinematics of the expanding mouth during prey capture by larval Sparus aurata were used to parameterize age-specific numerical models of the flows inside the mouth. These models reveal that, for small larvae that slowly expand their mouth, not all the fluid that enters the mouth cavity is expelled through the gills, resulting in flow reversal at the mouth orifice. This efflux at the mouth orifice was highest in the younger ages, but was also high (>8%) in slow strikes produced by larger fish. Our modeling explains the observations of “in-and-out” events in larval fish, where prey enters the mouth but is not swallowed. It further highlights the importance of prey transport as an integral part in determining suction feeding success.

Larval fishes of a Middle Atlantic Bight estuary: assemblage structure and temporal stability

1999 ◽  
Vol 56 (2) ◽  
pp. 222-230 ◽  
Author(s):  
David A Witting ◽  
Kenneth W Able ◽  
Michael P Fahay
Keyword(s):  
Continental Shelf ◽  
Dominant Species ◽  
Fish Assemblages ◽  
Larval Fish ◽  
Temporal Stability ◽  
Temperature Cycle ◽  
Sargasso Sea ◽  
Larval Fishes ◽  
Middle Atlantic ◽  
Lower Temperature

We collected weekly, quantitative ichthyoplankton samples over 6 years (1989-1994, 1309 samples) to identify temporal scales of variability in the abundance and occurrence of larval fish assemblages near Little Egg Inlet in southern New Jersey, U.S.A. We collected species that spawn in the estuary (30%), both the estuary and continental shelf (35%), continental shelf (25%), and the Sargasso Sea (10%). The following analyses suggest an annually repeated seasonal progression of species assemblages: (i) the rank abundance of the 20 dominant species did not change significantly from year to year, (ii) variation in the density of the dominant species was primarily explained by intraannual rather than interannual variation, and (iii) multivariate analysis of the assemblage matrix identified five seasonal assemblages that occurred during all six years. We found that the timing and duration of each of these seasonal groups were correlated with two characteristics of the annual temperature cycle, magnitude (higher or lower temperature) and trajectory (increasing vs decreasing temperature). We suggest that the repeated occurrence of larval fish assemblages in temperate estuaries along the U.S. coast may, in part, be driven by local environmental processes.

Detection and quantification of marine larvae orientation in the pelagic environment

2009 ◽  
Vol 7 (9) ◽  
pp. 664-672 ◽  
Author(s):  
Jean-Olivier Irisson ◽  
Cédric Guigand ◽  
Claire B. Paris
Keyword(s):  
Pelagic Environment ◽  
Marine Larvae ◽  
Detection And Quantification

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.

scholarly journals Lunar rhythms in growth of larval fish

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202609
Author(s):  
Jeffrey S. Shima ◽  
Craig W. Osenberg ◽  
Erik G. Noonburg ◽  
Suzanne H. Alonzo ◽  
Stephen E. Swearer
Keyword(s):  
Cloud Cover ◽  
Larval Fish ◽  
Larval Survival ◽  
Population Declines ◽  
Daily Growth ◽  
Growth And Survival ◽  
Larval Fishes ◽  
Diel Vertical Migrations ◽  
Periodic Growth ◽  
Thalassoma Hardwicke

Growth and survival of larval fishes is highly variable and unpredictable. Our limited understanding of this variation constrains our ability to forecast population dynamics and effectively manage fisheries. Here we show that daily growth rates of a coral reef fish (the sixbar wrasse, Thalassoma hardwicke ) are strongly lunar-periodic and predicted by the timing of nocturnal brightness: growth was maximized when the first half of the night was dark and the second half of the night was bright. Cloud cover that obscured moonlight facilitated a ‘natural experiment’, and confirmed the effect of moonlight on growth. We suggest that lunar-periodic growth may be attributable to light-mediated suppression of diel vertical migrations of predators and prey. Accounting for such effects will improve our capacity to predict the future dynamics of marine populations, especially in response to climate-driven changes in nocturnal cloud cover and intensification of artificial light, which could lead to population declines by reducing larval survival and growth.

scholarly journals Importance of prey size on investigating prey availability of larval fishes

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251344
Author(s):  
Yu-Hsuan Huang ◽  
Hsiao-Hang Tao ◽  
Gwo-Ching Gong ◽  
Chih-hao Hsieh
Keyword(s):  
Prey Size ◽  
Prey Availability ◽  
Larval Fish ◽  
Mesh Size ◽  
Fish Density ◽  
Natural Environments ◽  
Positive Relationships ◽  
Larval Fishes ◽  
Important Prey ◽  
The Relationship

Prey availability plays an important role in determining larval fish survival. Numerous studies have found close relationships between the density of mesozooplankton and larval fishes; however, emerging studies suggest that small-size zooplankton are more important prey for some larval fish species. One arising question is whether the size of zooplankton determines the relationship between zooplankton and larval fish community in natural environments. To address this question, we collected small-size (50–200 μm) zooplankton, mesozooplankton (> 330 μm), and larval fish using three different mesh-size (50, 330, 1000 μm, respectively) nets in the East China Sea, and examined their relationships in density. Both meso- and small-size zooplankton densities showed positive relationships with larval fish density, while the relationship is much stronger for the small-size zooplankton. Specifically, the smallest size classes (50–75 and 75–100 μm) of small-size zooplankton showed the highest positive relationships with larval fish density. Temperature, salinity, and chlorophyll-a concentration did not significantly explain larval fish density. Based on these findings, we demonstrate the importance of considering prey size when investigating prey availability for larval fishes.

Larval Fish Clamp: A Tool for Observing Larval Fishes

Copeia ◽  
1996 ◽  
Vol 1996 (1) ◽  
pp. 221 ◽  
Author(s):  
Toshiro Saruwatari ◽  
Akio Kaneko
Keyword(s):  
Larval Fish ◽  
Larval Fishes
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