scholarly journals Coastal winds drive a recruitment mechanism for estuarine fisheries

2020 ◽  
Author(s):  
Hayden T. Schilling ◽  
Charles Hinchliffe ◽  
Jonathan P. Gillson ◽  
Anthony Miskiewicz ◽  
Iain M. Suthers
Keyword(s):  
Larval Fish ◽  
Future Research ◽  
Larval Abundance ◽  
Spawning Period ◽  
Onshore Wind ◽  
Larval Recruitment ◽  
Australian Region ◽  
Coastal Winds ◽  
Key Driver ◽  
Catch Rates

AbstractCoastal winds transport larval fish onshore or offshore which may contribute to estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we show that larval abundance of coastally spawned species increased with weak to moderate upwelling favourable winds 14 days prior to sampling, reflecting increased nutrient and plankton availability for larval fish. A strong decline in larval abundance was observed following strong upwelling favourable winds while abundance increased with onshore (downwelling favourable) winds, in relation to offshore and onshore wind-driven transport. Subsequently, we show that effects of wind during the spawning period can be detected in lagged estuarine commercial fisheries catch rates of coastally spawned species (lagged by 2 – 8 years depending on species’ growth rates), representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may reduce larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the east Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds. As global winds are changing, it is important to investigate if this mechanism is applicable to other regions around the world where coastal winds are a key driver of upwelling.

Environmental influences on the larval recruitment dynamics of snapper, Chrysophrys auratus (Sparidae)

2013 ◽  
Vol 64 (8) ◽  
pp. 726 ◽  
Author(s):  
Carina J. Sim-Smith ◽  
Andrew G. Jeffs ◽  
Craig A. Radford
Keyword(s):  
Environmental Variables ◽  
High Water ◽  
Pelagic Larval Duration ◽  
Tidal Range ◽  
Good Survival ◽  
Larval Abundance ◽  
Larval Duration ◽  
Spawning Period ◽  
Larval Recruitment ◽  
Recruitment Success

Recruitment success in demersal fish species that settle in estuaries after a pelagic larval duration in coastal waters is dependent on (1) abiotic and biotic variables that promote good survival, and (2) local environmental conditions that facilitate and direct the transport of larvae to settlement habitats. In the present study, we described the patterns of larval abundance, pelagic larval duration and settlement of a commercially important sparid, Chrysophrys auratus, in northern New Zealand over 2 years, and investigated the relationships among pelagic larval duration or daily settler abundance and various environmental variables. Pelagic larval duration varied from 17 to 33 days and the successful spawning period that produced settled juveniles varied from 29 to 109 days among our four sites. For 91% of fish captured, the average temperature during the pelagic larval duration was >18°C. Significant correlations between daily settler abundance and environmental variables varied among sites and between years; however, temperature, tidal range and on-shore winds were most strongly correlated with settlement, explaining up to 38% of the variability in settler abundance. The present results suggested that, in some locations, high water temperatures, large tides and on-shore winds are likely to increase recruitment success in C. auratus.

scholarly journals Diel variation of larval fish abundance in the Amazon and Rio Negro

2001 ◽  
Vol 61 (3) ◽  
pp. 357-362 ◽  
Author(s):  
C. A. R. M. ARAUJO-LIMA ◽  
V. V. da SILVA ◽  
P. PETRY ◽  
E. C. OLIVEIRA ◽  
S. M. L. MOURA
Keyword(s):  
Larval Fish ◽  
Fish Abundance ◽  
Large Rivers ◽  
Larval Abundance ◽  
Diel Variation ◽  
Larval Drift ◽  
Larval Distribution ◽  
Rio Negro ◽  
One Year

Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.

Chronology, distribution, and sizes of larval fish sampled by light traps in macrophytic Chemung Lake

1985 ◽  
Vol 63 (11) ◽  
pp. 2569-2577 ◽  
Author(s):  
Robert S. Gregory ◽  
Perce M. Powles
Keyword(s):  
Common Carp ◽  
Yellow Perch ◽  
Larval Fish ◽  
Larval Abundance ◽  
Low Density ◽  
Light Traps ◽  
Resident Species ◽  
Emergence Period ◽  
Pumpkinseed Sunfish ◽  
Total Length

Light traps were used to assess larval abundance and chronology of appearance in Chemung Lake in 1982. Eleven of 21 resident species were captured, totalling 7234 individuals. The most abundant were yellow perch (2809), Iowa darter (2571), pumpkinseed sunfish (1288), bluntnose minnow (200), and carp (123). Iowa darter and pumpkinseed were taken only as prolarvae (yolk-sac larvae) and postlarvae, but yellow perch, from 5 to 33 mm total length, were attracted. Common carp and bluntnose minnow entered traps almost exclusively as prolarvae (6–13 mm and 6–12 mm total length, respectively). Perch had the shortest emergence period, May 6–12 (15–17 °C), followed by darters. May 9–31 (15–21 °C). Pumpkinseed and carp emerged over a 6-week period from June 3 to July 23 (16–25 °C). Perch prolarvae preferred shallow, high-density macrophyte areas; their postlarvae preferred deep, low-density macrophyte zones. All stages of larval darter selected shallow, macrophyte-dense regions, as did the young of pumpkinseed.

scholarly journals National Interest in Security Science

2021 ◽  
Vol 22 (3) ◽  
pp. 73-88
Author(s):  
Darko Trifunović ◽  
Milica Ćurčić
Keyword(s):  
National Interest ◽  
Future Research ◽  
National Interests ◽  
Relevant Today ◽  
Theoretical Assumptions ◽  
Key Factor ◽  
Solid Foundation ◽  
Key Driver ◽  
Raymond Aron ◽  
Security Science

The aim of this paper is a review of the conceptualization of national interest in the theoretical assumptions of realism. A review of the literature and its analysis provides an overview of the main findings of prominent realists who shaped the national interest and created a solid foundation for future research: Hans Morgentau, Raymond Aron, and Kenneth Waltz. Consequently, the scientific goals of this paper are to summarize the scope and manner of national interest’s thematization in realist’s research and, to analyze the significance of their scientific contribution to the Science of Security. National interest remains one of the most important terms in Security Science. A prudent articulation of national interests is a key factor for the security of any state, so understanding this concept is extremely important for Security Science theorists. A realistic understanding of the national interest as a key driver, but also a determinant of the behavior of states concerning other states, is still relevant today.

The effects of a tidal-mixing front on the distribution of larval fish habitats in a semi-enclosed sea during winter

2014 ◽  
Vol 94 (7) ◽  
pp. 1517-1530 ◽  
Author(s):  
Emilio A. Inda-Díaz ◽  
Laura Sánchez-Velasco ◽  
Miguel F. Lavín
Keyword(s):  
Gulf Of California ◽  
Larval Fish ◽  
Three Dimensional ◽  
Wide Distribution ◽  
Tidal Mixing ◽  
Larval Abundance ◽  
North West ◽  
North East ◽  
Tidal Mixing Front ◽  
Fish Habitats

We examined the effect of a tidal-mixing front on the three-dimensional distribution of larval fish habitats (LFHs) in the Midriff Archipelago Region in the Gulf of California during winter. Zooplankton and environmental variables were sampled from 0 to 200 m in 50 m strata. Four LFHs were defined in association with the front, two on the northern side and two on the southern side. The northern LFHs were: (1) the Mainland Shelf Habitat, located from the surface to 100 m depth on the north-east mainland shelf, characterized mainly by the presence of Citharichtys fragilis; and (2) the Wide Distribution Habitat, extending from north-west to south across the front from the surface to 200 m depth, dominated by the ubiquitous Engraulis mordax. The southern LFHs were: (3) the Eddy Zone Habitat, defined nearly on an anticyclonic eddy, with the highest larval abundance and richness from the surface to 100 m depth, dominated by Leuroglossus stilbius; and (4) the Southern Gulf Habitat, associated with low temperature waters from the southern Gulf of California, dominated by southern-gulf species (e.g. Scomber japonicus and Sardinops sagax). Despite the weak stratification and low thermal contrast (~1.5°C) across the south front compared to summer (~3°C), our results demonstrate that the frontal zone may influence the formation of planktonic habitats even during generally homogeneous periods, which may also be relevant in other regions of the world.

Larval fish drift in the Valley River, Manitoba: influence of abiotic and biotic factors, and relationships with future year-class strengths

1995 ◽  
Vol 52 (11) ◽  
pp. 2423-2431 ◽  
Author(s):  
Thomas A. Johnston ◽  
Marc N. Gaboury ◽  
Richard A. Janusz ◽  
Laureen R. Janusz
Keyword(s):  
Larval Fish ◽  
Common Species ◽  
Mature Female ◽  
Larval Abundance ◽  
White Sucker ◽  
Catch Per Unit Effort ◽  
Larval Drift ◽  
Class Strength ◽  
Median Date ◽  
Valley River

We examined patterns in the spring drift of larval fishes in the Valley River, Manitoba. White sucker (Catostomus commersoni) and walleye (Stizostedion vitreum) were the most common species. The median date of larval drift for walleye was significantly earlier than for all other species. Capture rates of all species were significantly greater during the night than during the day. Larval abundance was positively related to river discharge in the 35 d preceding the median date of larval drift. Larval abundance was also positively related to mature female biomass in Dauphin Lake for walleye, but not for white sucker. Year-class strength of a cohort (catch per unit effort of 3- or 4-year-old fish) in Dauphin Lake was positively related to total larval drift of the same cohort (3 or 4 years earlier) in the Valley River for walleye, but not for white sucker. Our results suggest that the year-class strength of Dauphin Lake walleye is determined very early in the life history and that factors which enhance the natural production of walleye larvae will enhance walleye recruitment.

Post-larval recruitment of blacklip abalone (Haliotis rubra) on artificial collectors in southern Tasmania

1995 ◽  
Vol 46 (3) ◽  
pp. 531 ◽  
Author(s):  
WJ Nash ◽  
JC Sanderson ◽  
J Bridley ◽  
S Dickson ◽  
B Hislop
Keyword(s):  
Sea Water ◽  
Larval Settlement ◽  
Water System ◽  
Early Spring ◽  
Larval Abundance ◽  
Second Phase ◽  
Larval Recruitment ◽  
Stage Process ◽  
Flow Through ◽  
Haliotis Rubra

Recruitment rates of blacklip abalone (Haliotis rubra) post-larvae were measured at fortnightly intervals for a year in southern Tasmania on larval collectors made of transparent, corrugated plastic. The settlement plates were conditioned prior to use in a flow-through sea-water system in a two-stage process. A film of diatoms (mainly Nitzschia and Navicula species) was first established on the plates, which were then grazed by juvenile H. rubra. This allowed second-phase algae (principally Myrionema species) to become established. The plates were then periodically deployed at a depth of ~7 m. Larval settlement occurred mainly during the austral winter and early spring. A peak settlement rate of 1408 post-larvae per collector (2347 post-larvae m-2) occurred in mid August. Methods of measuring larval or immediate post-larval abundance are reviewed with regard to their use in the assessment and management of abalone fisheries.

scholarly journals The Programmable Data Plane: Abstractions, Architectures, Algorithms, and Applications

2020 ◽  
Author(s):  
Oliver Michel ◽  
Roberto Bifulco ◽  
Gábor Rétvári ◽  
Stefan Schmid
Keyword(s):  
Network Services ◽  
Future Research ◽  
Next Generation ◽  
Low Level ◽  
Design And Implementation ◽  
The Past ◽  
Data Plane ◽  
Recent Trends ◽  
Key Driver ◽  
Processing Steps

<div><div>Programmable data plane technology enables the systematic reconfiguration of the low-level processing steps applied to network packets and is a key driver in realizing the next generation of network services and applications. This survey presents recent trends and issues in the design and implementation of programmable network devices, focusing on prominent architectures, abstractions, algorithms, and applications proposed, debated, and realized over the past years. We elaborate on the trends that led to the emergence of this technology and highlight the most important pointers from the literature, casting different taxonomies for the field and identifying avenues for future research.</div></div>

Reproductive Patterns of Pacific Ocean Perch (Sebastodes alutus) off Washington and British Columbia and their Relation to Bathymetric Distribution and Seasonal Abundance

1971 ◽  
Vol 28 (3) ◽  
pp. 417-425 ◽  
Author(s):  
Donald R. Gunderson
Keyword(s):  
British Columbia ◽  
Pacific Ocean ◽  
Deep Water ◽  
Seasonal Abundance ◽  
Bathymetric Distribution ◽  
Mating Period ◽  
Spawning Period ◽  
Reproductive Patterns ◽  
Catch Rates ◽  
Spring Maximum

Females of the ovoviviparous species Sebastodes alutus release their larvae in March in the Washington–British Columbia area. Male maturity data from Queen Charlotte Sound indicated that males probably inseminate females in September or October. Examination of the annual bathymetric cycle in three major commercial trawling areas showed that mating and insemination occur while Pacific ocean perch are moving to deep water from the shallow-water regions inhabited in summer and that females release their larvae while in the deepest part of their bathymetric range.Total 1955 through 1965 catch by month, and 11-year mean monthly catch rates were used to indicate relative seasonal abundance on major fishing grounds. Where deepwater regions were trawled, these indices showed a spring maximum associated with the March spawning period. In all areas studied there was a midsummer slump in catch and catch rate, and an October maximum occurring during the suggested mating period.

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