Optimal Environmental Window and Pelagic Fish Recruitment Success in Upwelling Areas

1989 ◽  
Vol 46 (4) ◽  
pp. 670-680 ◽  
Author(s):  
Philippe Cury ◽  
Claude Roy
Keyword(s):  
Wind Speed ◽  
Food Availability ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Physical Constraints ◽  
Fish Recruitment ◽  
The Pacific ◽  
Engraulis Ringens ◽  
Upwelling Intensity ◽  
Wind Mixing

Food availability and physical constraints such as turbulence are now considered as important factors that affect larval survival and pelagic fish recruitment. In Ekman-type upwelling, vertical advection, new inputs of nutrients and turbulence are linked to wind speed. According to the literature, food availability for larvae is related to biological dynamics (primary production) up to a point where the biological processes are disturbed by physical processes (turbulence generated by wind mixing). This limitation does not exist for non Ekman-type upwelling where upwelling intensity is not correlated with wind speed. We hypothesize that relations between annual recruitments and upwelling intensity are dome shaped in Ekman-type upwellings and linear for non Ekman-type upwellings. A statistical method is used to analyse the form of the relationships between recruitments and upwelling indices or wind mixing. The recruitment of the Peruvian anchoveta (Engraulis ringens), of the Pacific sardine (Sardinops sagax caerulea) and of the West African sardines and sardinellas are thereby examined. Results show that for Ekman-type upwelling the annual recruitment increases with upwelling intensity until wind speed reaches a value of roughly 5–6 m∙s−1 and decreases for higher values. For a non Ekman-type upwelling the relationship between recruitment and upwelling intensity is linear. These results confirm the existence of an optimal environmental window for recruitment.

scholarly journals Spawning stock, egg production and larval survival in relation to small pelagic fish recruitment

2019 ◽  
Vol 617-618 ◽  
pp. 113-136 ◽  
Author(s):  
S Somarakis ◽  
S Tsoukali ◽  
M Giannoulaki ◽  
E Schismenou ◽  
N Nikolioudakis
Keyword(s):  
Egg Production ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Small Pelagic Fish ◽  
Fish Recruitment ◽  
Spawning Stock

The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés
Keyword(s):  
Field Data ◽  
Fish Larvae ◽  
Larval Growth ◽  
Warming Trend ◽  
Mortality Rates ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Balance Model ◽  
Small Pelagic Fish ◽  
Mesoscale Structures

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

Climate change scenarios experiments predict a future reduction in small pelagic fish recruitment in the Humboldt Current system

2013 ◽  
Vol 19 (6) ◽  
pp. 1841-1853 ◽  
Author(s):  
Timothée Brochier ◽  
Vincent Echevin ◽  
Jorge Tam ◽  
Alexis Chaigneau ◽  
Katerina Goubanova ◽  
...  
Keyword(s):  
Climate Change ◽  
Current System ◽  
Pelagic Fish ◽  
Climate Change Scenarios ◽  
Small Pelagic Fish ◽  
Humboldt Current ◽  
Fish Recruitment ◽  
Humboldt Current System

scholarly journals Formation and distribution of sea-surface microlayers

2010 ◽  
Vol 7 (4) ◽  
pp. 5719-5755 ◽  
Author(s):  
O. Wurl ◽  
E. Wurl ◽  
L. Miller ◽  
K. Johnson ◽  
S. Vagle
Keyword(s):  
Wind Speed ◽  
Primary Production ◽  
Sea Surface ◽  
Surface Microlayer ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind ◽  
The Pacific ◽  
Sea Surface Microlayer ◽  
Natural Surfactants

Abstract. Results from a study of surfactants in the sea-surface microlayer (SML) in different regions of the ocean (subtropical, temperate, polar) suggest that this interfacial layer between the ocean and atmosphere covers the ocean's surface to a significant extent. Threshold values at which primary production acts as a significant source of natural surfactants have been derived from the enrichment of surfactants in the SML relative to underlying water and local primary production. Similarly, we have also derived a wind speed threshold at which the SML is disrupted. The results suggest that surfactant enrichment in the SML is typically greater in oligotrophic regions of the ocean than in more productive waters. Furthermore, the enrichment of surfactants persisted at wind speeds of up to 10 m s−1 without any observed depletion above 5 m s−1. This suggests that the SML is stable enough to exist even at the global average wind speed of 6.6 m s−1. Global maps of primary production and wind speed are used to estimate the ocean's SML coverage. The maps indicate that wide regions of the Pacific and Atlantic Oceans between 30° N and 30° S are more significantly affected by the SML than northern of 30° N and southern of 30° S due to higher productivity (spring/summer blooms) and wind speeds exceeding 12 m s−1 respectively.

scholarly journals Regional-scale changes in diatom distribution in the Humboldt upwelling system as revealed by remote sensing: implications for fisheries

2010 ◽  
Vol 68 (4) ◽  
pp. 729-736 ◽  
Author(s):  
Thomas Jackson ◽  
Heather A. Bouman ◽  
Shubha Sathyendranath ◽  
Emmanuel Devred
Keyword(s):  
Remote Sensing ◽  
El Niño ◽  
El Nino ◽  
Regional Scale ◽  
Detection Algorithm ◽  
Larval Survival ◽  
Upwelling System ◽  
Diatom Population ◽  
Engraulis Ringens ◽  
Zooplankton Communities

Abstract Jackson, T., Bouman, H. A., Sathyendranath, S., and Devred, E. 2011. Regional-scale changes in diatom distribution in the Humboldt upwelling system as revealed by remote sensing: implications for fisheries. – ICES Journal of Marine Science, 68: 729–736. A diatom-detection algorithm was parametrized for the Humboldt upwelling system using local cruise data that were first validated, then used to create monthly composites of diatom distribution from 0 to 40°S and 90 to 70°W for both normal and El Niño conditions. There was a 50% reduction in the areal extent of diatom-dominated waters during the peak of the 1997 El Niño. The extent of the coastward contraction in the diatom-dominated area varied along the South American coastline. These regional shifts in phyto- and zooplankton communities would have increased food stress on local anchovy (Engraulis ringens) populations and could have contributed to diminished larval survival and landings the following year. A region of strong upwelling over the wide Peruvian continental shelf around 15°S was the only area that maintained a strong diatom population throughout the El Niño; the area may require special protection from fishing pressure in years following an El Niño event.

Aquaculture Revisited

1976 ◽  
Vol 33 (4) ◽  
pp. 880-887 ◽  
Author(s):  
John E. Bardach
Keyword(s):  
Social Impact ◽  
Information Dissemination ◽  
Raw Materials ◽  
Survival Rates ◽  
Larval Survival ◽  
Larval Rearing ◽  
Tropical Asia ◽  
Economy Of Scale ◽  
The Pacific ◽  
Choice Of Species

Opportunities for and constraints of animal aquaculture are considered with special reference to the Pacific basin. Choice of species for husbandry depends on biological, cultural, and marketability criteria. Seed production (spawning and larval rearing) may be centralized, with certain economy of scale advantages, even in artisanal aquaculture enterprises, provided adequate distribution facilities for postlarvae are made. Larval survival rates for several actual or potential cultivars still need enhancement through applied research. Practices for the growout phase of aquatic stock differ, depending on the intensity of fixed and variable inputs, by analogy with terrestrial systems one may distinguish feedlot, managed pasturage, and ranching modes. For much of tropical Asia best expansion opportunities exist in managed pasturage polyculture possibly combining the grow-out of crustacea for export with local, largely herbivorous and planktivorous semistaple species. Extraneously supplied feeds, when used, will differ with the species and locally available raw materials. Nonbiotechnical constraints to aquaculture expansion are found in the areas of training, credit, extension, social impact of change, and information dissemination. They may be as difficult, if not more difficult, to overcome as purely biological ones.

The Impact of Tributyl Tin (TBT) Antifouling Paints on Molluscan Fisheries

1986 ◽  
Vol 18 (4-5) ◽  
pp. 193-202 ◽  
Author(s):  
J. E. Thain ◽  
M. J. Waldock
Keyword(s):  
Field Experiments ◽  
Reproductive Behaviour ◽  
Larval Survival ◽  
Organotin Compounds ◽  
Contributory Factor ◽  
Ostrea Edulis ◽  
Antifouling Paints ◽  
The Pacific ◽  
The Uk ◽  
The Impact

Laboratory and field experiments carried out during 1982–84 confirmed that some UK estuaries contained sufficient organotin compounds to cause reduced meat yields and shell thickening in the Pacific oyster, Crassostrea gigas. Historically the European flat oyster, Ostrea edulis, has been the basis of an important fishery on the east coast of England but the population has recently declined to an all-time low. Laboratory experiments have been carried out to compare larval survival, growth of spat and the development of gametes in adult O. edulis, and the growth of spat of four other bivalve species in the presence and absence of organotin toxins. The results from these experiments are discussed in relation to the concentrations of organotin compounds in samples of water and oyster tissues, from several sites in the UK, and the reproductive behaviour of adult oysters from natural stocks in the Crouch/Roach estuary system. The data strongly suggest that TBT is at least a contributory factor and probably a major cause of the failure in recent years of O. edulis to reproduce naturally in the Crouch Estuary. The UK Government has proposed legislation to control and reduce organotin emissions into the marine environment and this is briefly outlined.

scholarly journals Propagating Atmospheric Patterns Associated with Midwest Winter Precipitation

2012 ◽  
Vol 13 (4) ◽  
pp. 1371-1382 ◽  
Author(s):  
Courtenay Strong ◽  
Jessica Liptak
Keyword(s):  
Wind Speed ◽  
Daily Precipitation ◽  
Winter Precipitation ◽  
Precipitation Variability ◽  
Jet Stream ◽  
Study Region ◽  
Lake Effect ◽  
The Pacific ◽  
High Precipitation ◽  
Transport Patterns

Abstract For winters over eastern North America, complex Hilbert empirical orthogonal function (HEOF) analysis was used to objectively identify propagating patterns in four atmospheric fields that have potential relevance to precipitation: jet stream–level wind speed, 850-hPa moisture transport (qv), temperature advection (TA), and vorticity advection (VA). A novel phase shift method was used to show the location where each propagating pattern was most correlated with Midwest precipitation, and each of the four phase-shifted HEOF patterns was compared to its respective high-precipitation composite view. The leading HEOFs of the three transport fields (qv, TA, and VA), which collectively represented the dynamics associated with a midlatitude cyclone, accounted for almost half of Midwest precipitation variability and were associated with lake effect snow when propagating downstream from the Midwest. Correlation and spectral analyses revealed how the propagating transport patterns were related to the Pacific–North American pattern and other teleconnections. The leading HEOF of jet stream–level wind speed, which represented the tendency for the jet stream to migrate equatorward over the study region during winter, accounted for only about 4% of Midwest daily precipitation variability. In contrast, the second HEOF of jet stream–level wind speed, which represented an eastward propagating trough dynamically consistent with a midlatitude cyclone, accounted for 16% of Midwest daily precipitation variability.

Effect of food availability on reproduction and brood size in a freshwater brooding bivalve

2003 ◽  
Vol 81 (7) ◽  
pp. 1168-1173 ◽  
Author(s):  
Mark A Beekey ◽  
Ronald H Karlson
Keyword(s):  
Food Availability ◽  
Brood Size ◽  
Reproductive Strategies ◽  
Common Garden ◽  
Relative Importance ◽  
Common Garden Experiment ◽  
Freshwater Bivalve ◽  
Physical Constraints ◽  
Effect Of Food ◽  
Energetic Constraints

Brood size is often constrained by the amount of energy available to produce offspring. Yet, energetic constraints may not be as important if the physical capacity to brood offspring is limited. Investigating the relative importance of energetic and physical constraints on brood size is necessary to understand how reproductive strategies are molded by natural selection. We investigated how food availability affects brood size in Sphaerium striatinum, a freshwater bivalve. We reared juveniles to adulthood under three food levels in a common garden experiment. The number of reproductive attempts, brood size, and stage of offspring development were measured. Clams reared with the most food reproduced more often, produced more offspring per reproductive attempt, and contained larger broods than clams reared with less food. These data support the notion that food availability is an important factor in the production of offspring and overall brood size. However, the number of offspring surviving to later stages of development was not different among treatments. In fact, clams reared with the most food lost proportionately more offspring than clams reared with less food. We conclude that physical constraints are more important in determining overall brood size than energetic constraints in S. striatinum.

scholarly journals Using Microwave Satellite Data to Assess Changes in Storminess over the Pacific Ocean

2015 ◽  
Vol 143 (8) ◽  
pp. 3214-3229 ◽  
Author(s):  
Michael C. Kruk ◽  
Kyle Hilburn ◽  
John J. Marra
Keyword(s):  
Wind Speed ◽  
Pacific Ocean ◽  
Rain Rate ◽  
The United States ◽  
The Philippines ◽  
Tropical Pacific ◽  
Central Pacific ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Increasing Trends

Abstract This study analyzes 25 years of Special Sensor Microwave Imager (SSM/I) retrievals of rain rate and wind speed to assess changes in storminess over the open water of the Pacific Ocean. Changes in storminess are characterized by combining trends in both the statistically derived 95th percentile exceedance frequencies of rain rate and wind speed (i.e., extremes). Storminess is computed annually and seasonally, with further partitioning done by phase of the El Niño–Southern Oscillation (ENSO) index and the Pacific decadal oscillation (PDO) index. Overall, rain-rate exceedance frequencies of 6–8 mm h−1 cover most of the western and central tropical Pacific, with higher values present around the Philippines, Japan, Mexico, and the northwest coast of Australia. Wind speed exceedance frequencies are a strong function of latitude, with values less (greater) than 12 m s−1 equatorward (poleward) of 30°N/S. Statistically significant increasing trends in rain rate were found in the western tropical Pacific near the Caroline Islands and the Solomon Islands, and in the extratropics from the Aleutian Islands down the coast along British Columbia and Washington State. Statistically significant increasing trends in wind speed are present in the equatorial central Pacific near Kiribati and the Republic of the Marshall Islands (RMI), and in the extratropics along the west coast of the United States and Canada. Thus, while extreme rain and winds are both increasing across large areas of the Pacific, these areas are modulated according to the phase of ENSO and the PDO, and their intersection takes aim at specific locations.

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