Larval fish body growth responses to simultaneous browning and warming

Present investigation was undertaken to standardize technique for in vitro micro-propagation of chickpea( Cicer arietinum ) cultivar Vishwas (Phule G 12). Micropropagation method for chickpea was established and this method enabled much more efficient propagation of plants. The present work was aimed at evolving a protocol for rapid multiplication of chickpea using micropropagation technique. Explants from shoot tip and node segment were cultured on MS medium supplemented with different concentrations of BAP and Kinetin (1.0 to 2.5 mg/l) and their growth responses like shooting were elucidated. The maximum multiple response was observed with 2 mg/l concentration of BAP from both types of explant. The highest number of shoots (12.5 ± 0.3) was achieved on MS medium with 2 mg/l BAP using node segments. The medium supplemented with 2 mg/l of BAP was found better than all other concentrations. Individual shoots were transferred to IBA and IAA (1.0-1.5 mg/l) for root induction. MS medium supplemented with 2 mg/l of IBA proved better for rooting. Rooted plantlets were successfully hardened in greenhouse and established in the pot.

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Prey tell: what quillback rockfish early life history traits reveal about their survival in encounters with juvenile coho salmon

Marine Ecology Progress Series ◽

10.3354/meps13300 ◽

2020 ◽

Vol 650 ◽

pp. 7-18 ◽

Cited By ~ 1

Author(s):

HW Fennie ◽

S Sponaugle ◽

EA Daly ◽

RD Brodeur

Keyword(s):

Life History ◽

Early Life ◽

Life History Traits ◽

Direct Evidence ◽

Coho Salmon ◽

Larval Fish ◽

Early Life History ◽

In The Wild ◽

Otolith Microstructure Analysis ◽

Pelagic Juvenile

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.

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

Marine Ecology Progress Series ◽

10.3354/meps13404 ◽

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.

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ALTERNATIVE P-FERTILISERS FOR NORTHLAND SOILS

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1986.47.1734 ◽

1986 ◽

pp. 229-232

Author(s):

P.W. Shannon

Keyword(s):

Phosphate Rock ◽

Growth Responses ◽

Triple Superphosphate ◽

Rock Phosphates ◽

Distribution Costs ◽

Phosphate Retention ◽

Sechura Phosphate Rock ◽

Local Product ◽

Application Frequency ◽

Chatham Rise Phosphorite

Increasing material, processing, and distribution costs have raised superphosphate prices to a point where many farms cannot support the costs of meeting maintenance phosphate requires men& Alternatives to superphosphate, particularly those that have lower processing costs and contain more P, may offer a solution to the problem provided they are agronomically as effective. Phosphate rock may indeed be such an alternative. Preliminary results from a series of five trials in Northland show that on soils of moderate P fertility, with low phosphate retention (PR) and high pH (5.9.6.0), initial pasture growth responses to rock phosphates are smaller than those from single or triple superphosphate. On one soil of higher PR and lower pH, the differences in yield between the rock-phosphates and the super. phosphates were smaller. Of the rock phosphates tested, Sechura and North Carolina (unground and ungranulated) tended to be more effective than ground and granulated Chatham Rise phosphorite. The effect on production of applying fertilisers once every three years, as opposed to annual applications is being investigated using triple superphosphate and Sechura phosphate rock. After two years, production levels appear largely unaffected by differences in application frequency. A comparison of locally-produced superphosphate with a reference standard showed that both performed similarly, indicating that the local product was of satisfactory quality.

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