scholarly journals Relationships between fish larvae and siphonophores in the water column: effect of wind-induced turbulence and thermocline depth

2007 ◽  
Vol 64 (5) ◽  
pp. 878-888 ◽  
Author(s):  
L. Sanvicente-Añorve ◽  
M. A. Alatorre ◽  
C. Flores-Coto ◽  
C. Alba

Abstract Sanvicente-Añorve, L., Alatorre, M. A., Flores-Coto, C., and Alba, C. 2007. Relationships between fish larvae and siphonophores in the water column: effect of wind-induced turbulence and thermocline depth. – ICES Journal of Marine Science, 64: 878–888. The relationship between the abundance of fish larvae and siphonophores in relation to wind-induced turbulence and thickness of the mixed layer in the southern Gulf of Mexico were studied during two periods of different wind conditions: April (5.25 m s−1) and October (6.5 m s−1). The Spearman correlation between fish larvae and siphonophores revealed a random relationship in the 0–10 m layer during April and in the 0–20 m layer in October. This structure presumably persists while turbulent forces remain at sufficient strength. Positive patterns were observed deeper in the water column. Whereas thermocline position did not correspond with the depth separating random and positive relationships, low turbulence values did. Observations indicate that turbulent kinetic energy values above 4 × 10−4 J kg−1 might promote a random distribution between potential prey and predator zooplankton taxa. In surface waters, contact rates between siphonophores and fish larvae showed that turbulence enhances encounters 2.5 (1.2) times in April and 3.3 (1.3) times in October for prey velocities of 0.003 (0.011) m s−1. The positive relationship between fish larvae and siphonophores could be caused by a high degree of spatial overlap, enough food for both groups, and limited predation on larvae in the presence of alternative prey. Seasonal variability in the vertical structure of distribution patterns was attributed mainly to aggregative feeding behaviour of organisms and disruption of patches as a consequence of small-scale water turbulence.

Author(s):  
R. P. Harris ◽  
L. Fortier ◽  
R. K. Young

A large-volume pump system (2.8 m3 min-1) for sampling fish larvae under open-sea conditions is described. Comparative efficiency trials by day and night showed that the pump was generally as efficient, or in some cases more efficient, in capturing larvae than vertically hauled 200 μm WP2 nets, though there was some evidence of visual avoidance by particular larval size classes during daylight. The pump system is particularly appropriate for investigating fine-scale vertical aggregations (1–10 m3) of larval fish in relation to the distribution of their food organisms.INTRODUCTIONStudies of the distribution of larval fish and their food organisms in relation to physical structure in the water column require sampling techniques capable of resolving fine-scale temporal and spatial distributions. As an alternative to conventional nets, large-volume pumps, sampling at rates in excess of 1 m3 min-1; provide such a capability. Major benefits of using large pumps in addition to temporal and spatial resolution are that a wide range of sizes of plankton including larval fish can be sampled simultaneously in relation to physical and chemical properties of the water column; there is reliable control of the volume of sample filtered and problems of clogging of towed nets are avoided; long series of sequential samples can be taken in studies of small-scale distribution; and instrumentation with in situ CTD and fluorometers at the intake enables real-time control of sampling in relation to physical structure.General engineering considerations for using such pumps have been reviewed in detail by Miller & Judkins (1981), and a particular area of application has been in power-plant entrainment studies in shallow fresh water (Portner & Rhode, 1977; Bowles & Merriner, 1978; Gale & Mohr, 1978; Ney & Schumacher, 1978; Elder et al. 1979; Leithiser, Ehrlich & Thum, 1979; Cada & Loar, 1982).


2004 ◽  
Vol 61 (8) ◽  
pp. 1243-1252 ◽  
Author(s):  
A. Sabatés

Abstract The vertical distributions of the larvae of shelf and oceanic fish species that spawn during the winter-mixing period in the Mediterranean are described from 22 vertically stratified plankton tows. Diel differences in the vertical distribution patterns in relation to physical data and potential prey abundance throughout the water column were examined. Even in absence of stratification, the larvae of the various fish species showed different patterns of vertical distribution and diel changes. The larvae of shelf-dwelling species were found in the surface layers, mainly above 50-m depth, and with some exceptions, with very little diel variation in depth distribution. Therefore, the vertical distribution of the larvae of these species coincided with the maximum concentrations of their potential food, nauplii and copepodite stages of copepods. The larvae of mesopelagic fishes showed deeper distributions in the water column and most of these species were located closer to the surface during the day than at night. Given the homogeneity of the physical characteristics throughout the water column, except for light, this behaviour may be determined not only by the higher concentration of prey in the surface layers but also by adequate light levels for feeding.


2021 ◽  
Vol 49 (2) ◽  
pp. 369-375
Author(s):  
Iván Velázquez-Abunader ◽  
Thierry Brulé ◽  
Miguel A. A. Cabrera ◽  
Jorge A. A. López-Rocha

The relationship between total length and total weight (LWR) of four commercial species of finfish captured in the southern Gulf of Mexico (Lachnolaimus maximus, Ocyurus chrysurus, Mycteroperca bonaci, and Mycteroperca microlepis) was estimated. Two of these species are captured in the region by the small-scale fleet, while the other two are targeted by small-scale and semi-industrial fleets using harpoons, handlines, and long-lines. For the assessment, the organisms were sampled at the landing decks in the study area in two periods: 1996-1999 (semi-industrial fleet) and from April 2017 to May 2018 (small-scale fleet). A total of 2780 individuals were sampled which 2775 individuals were used to obtain LWR functions. The four species showed negative allometric growth with b < 3 for the 2017-2018 period, two species showed positive allometric growth with b > 3 for the 1996-1999 period. This type of information is an important input for the stock assessment of these species that support important fisheries in the zone and are under high fishing pressure levels.


2020 ◽  
Vol 13 (2) ◽  
pp. 112-121
Author(s):  
Sudiyar . ◽  
Okto Supratman ◽  
Indra Ambalika Syari

The destructive fishing feared will give a negative impact on the survival of this organism. This study aims to analyze the density of bivalves, distribution patterns, and to analyze the relationship of bivalves with environmental parameters in Tanjung Pura village. This research was conducted in March 2019. The systematic random system method was used for collecting data of bivalves. The collecting Data retrieval divided into five research stasions. The results obtained 6 types of bivalves from 3 families and the total is 115 individuals. The highest bivalve density is 4.56 ind / m², and the lowest bivalves are located at station 2,1.56 ind / m²,  The pattern of bivalve distribution in the Coastal of Tanjung Pura Village is grouping. The results of principal component analysis (PCA) showed that Anadara granosa species was positively correlated with TSS r = 0.890, Dosinia contusa, Anomalocardia squamosa, Mererix meretrix, Placamen isabellina, and Tellinella spengleri were positively correlated with currents r = 0.933.


Author(s):  
М.В. ДОВЫДЕНКОВА

Проведена статистическая обработка сформированной базы данных показателей неспецифической резистентности MS «Excel» с целью изучения динамики иммунитета по параметрам бактерицидной, лизоцимной и фагоцитарной активности у крупного рогатого скота черно-пестрой породы разных возрастов. Было установлено, что средние значения показателей лизоцимной и бактерицидной активности у телят в 6 мес были ниже (47,89% и 49,09%, соответственно), чем у животных в 3—4 года (53,75% и 52,81%). Выведено уравнение регрессии, описывающее взаимосвязь между средними показателями фагоцитарной активности и возрастом при высокой степени достоверности (R2=0,90). Изменения лизоцимной и бактерицидной активности в зависимости от возраста были недостоверными (R2=0,58 и R2=0,49, соответственно). Установлена высокая корреляция между бактерицидной и лизоцимной активностью. Отмечена динамика изменения неспецифического иммунитета у коров различных возрастных групп. Создание баз данных и постоянный мониторинг основных показателей естественной резистентности в зависимости от различных факторов (породы, возраста, стадий лактации, кормления, способов содержания), которые влияют на данные показатели, необходимо для оценки физиологического состояния организма животных и их устойчивости к болезням. Statistical processing of the generated MS "Excel" on indicators of non-specific resistance database was carried out with the aim of studying the dynamics of the development of immunity in terms of bactericidal, lysozyme and phagocytic activity in black-and-white cattle of different ages. It was found that the average values of indicators of lysozyme and bactericidal activity in calves at 6 months were lower (47.89% and 49.09%, respectively) than in animals at the age of 3—4 years (53.75% and 52.81%). The equation of regression was derived, it describes the relationship between the average indicators of phagocytic activity and the age with a high degree of reliability (R2=0.90). The changes in lysozyme and bactericidal activity depending on age were dubious (R2=0.58 and R2=0.49, respectively). The high correlation between bactericidal and lysozyme activity was established. It was noticed that the cows of different age groups experienced the dynamics of changes in nonspecific immunity. The creation of databases and constant monitoring of the main indicators of natural resistance, depending on various factors (breed, age, stages of lactation, feeding, methods of keeping) that affect these indicators, is necessary for assessing the physiological state of the animals’ body of and their resistance to diseases.


2019 ◽  
Vol 8 ◽  
pp. 54-56
Author(s):  
Ashmita Dahal Chhetri

Advertisements have been used for many years to influence the buying behaviors of the consumers. Advertisements are helpful in creating the awareness and perception among the customers of a product. This particular research was conducted on the 100 young male and female who use different brands of product to check the influence of advertisement on their buying behavior while creating the awareness and building the perceptions. Correlation, regression and other statistical tools were used to identify the relationship between these variables. The results revealed that the relationship between media and consumer behavior is positive. The adve1tising impact on sales and there is positive and high degree relationship between advertising and consumer behavior. The impact on advertising of a product of electronic media is better than non-electronic media.


1983 ◽  
Vol 245 (3) ◽  
pp. R353-R356
Author(s):  
W. W. Winder ◽  
M. A. Beattie ◽  
E. O. Fuller

The purposes of this study were to determine the effect of different work rates on the rate of liver glycogenolysis and to determine the relationship between liver adenosine 3',5'-cyclic monophosphate (cAMP) levels and the glycogenolytic rate. Rats were run at treadmill speeds ranging from 10 to 34 m/min up a 15% grade for either 30 or 60 min. Both the magnitude of the decrease in liver glycogen and the increase in hepatic cAMP were dependent on the running speed and the duration of running. At the highest work rate a disproportionate acceleration in the liver glycogenolytic rate was observed compared with that at lower work loads, thus resulting in a curvilinear relationship between work rate and liver glycogenolytic rate. A high degree of correlation was found between the liver glycogenolytic rate and hepatic cAMP concentration (r = 0.98). This observation is consistent with the idea that hepatic glycogenolytic rates are determined by cAMP-mediated mechanisms.


China Report ◽  
2021 ◽  
Vol 57 (1) ◽  
pp. 7-21
Author(s):  
Stephen Nagy

The Indo-Pacific region is now home to at least two competing regionalism road maps, China’s Belt Road Initiative (BRI) and Japan’s Free and Open Indo-Pacific Vision (FOIP). Through comparing their respective development trajectories, this article examines the relationship between these two regionalisation initiatives. Key lines of enquiry include the following: Is the interaction between the BRI and the FOIP Vision reactive, proactive or both? Why has each initiative changed its trajectory? How can we characterise these competing initiatives? This article employs a regionalism matrix analysis that compares two different approaches, integration from a ‘rational-legal perspective’ with an emphasis on broad cooperation and state sovereignty from a ‘process-oriented perspective’ with a focus on exact goals. It finds that the BRI focuses on both a high degree of state sovereignty based on a ‘process-oriented perspective’ and exact cooperation. In contrast, FOIP stresses integration through a ‘rational-legal perspective’, broad cooperation and a shared rules-based order. Furthermore, there is a reactive interplay between these two regionalism frameworks that shapes their orientation and influences their focus.


2021 ◽  
pp. 000312242199668
Author(s):  
Patricia Homan ◽  
Amy Burdette

An emerging line of research has begun to document the relationship between structural sexism and health. This work shows that structural sexism—defined as systematic gender inequality in power and resources—within U.S. state-level institutions and within marriages can shape individuals’ physical health. In the present study, we use a novel dataset created by linking two nationally representative surveys (the General Social Survey and the National Congregations Study) to explore the health consequences of structural sexism within another setting: religious institutions. Although religious participation is generally associated with positive health outcomes, many religious institutions create and reinforce a high degree of structural sexism, which is harmful for health. Prior research has not reconciled these seemingly conflicting patterns. We find that among religious participants, women who attend sexist religious institutions report significantly worse self-rated health than do those who attend more inclusive congregations. Furthermore, only women who attend inclusive religious institutions exhibit a health advantage relative to non-participants. We observe marginal to no statistically significant effects among men. Our results suggest the health benefits of religious participation do not extend to groups that are systematically excluded from power and status within their religious institutions.


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