Shoaling

A s firms are witnessing uncertain business conditions and more thrust is being given to agility, speed, and market responsiveness rather than scale and size, operating in a shoaling form is a desired strategy across many industries.
Shoaling can be considered a unique business strategy, because it enables a large firm to operate with the nimbleness of a smaller
firm or it can allow small firms to effectively rally their resources
against large rivals. A shoaling strategy, on the one hand, reduces the opportunity cost of not exploiting emerging market opportunities and, on
the other hand, reduces the investment risk that accrues due to large‐scale integration. A shoaling form enables multipronged competitive strategies, permitting a firm to develop unique or optimal strategy for
each rival it encounters in the respective market or region.

Zebrafish are at the forefront of neurobiological research and have been gaining popularity as a viable and valid behavioral model in a variety of research applications (e.g., assessing drug induced behavioral changes). This model becomes even more attractive when considering the behavioral changes that follow exposure to compounds that are water-soluble. As such, several studies have implicated both acute and chronic ethanol exposure in the modulation of zebrafish behavior. Within this arena there appears to be a common trend across multiple studies. As with many drugs ethanol appears to influence behavior in a dose-dependent manner. In this review, we compare and contrast several studies that measure behavior as a result of alcohol exposure. Appended to this review are pilot data that report zebrafish blood alcohol concentrations as a function of acute exposure.

The impact of hydropower plants on the environment varies greatly, depending on site-specific mitigation measures and production strategies: if badly managed, hydropower production can reduce biodiversity and can significantly degrade fluvial ecosystems and associated ecosystem services.Ocean waves are an immense, unused source of energy. Since global attention is nowadays constantly being drawn to the fact that the level of CO2 is rising, creating the so called “greenhouse effect”, and influencing further climate changes, the focus on generating electricity from renewable sources forces itself as an important area of future research. The possibility to exploit the energy potential created by sea waves indisputably exists. Various researches conducted in the field of unused energy sources prove the necessity of seriously considering this potential of sea waves. The illustration of this point in noted in a recently performed estimation that up to 15 per cent of current UK electricity...

Many animals live in groups because of the potential benefits associated with defense and foraging. Group living may also induce a 'calming effect' on individuals, reducing overall metabolic demand. This effect could occur by minimising the need for individual vigilance and reducing stress through social buffering. However, this effect has proved difficult to quantify. We examined the effect of shoaling on metabolism and body condition in the gregarious damselfish Chromis viridis Using a novel respirometry methodology for social species, we found that the presence of shoal-mate visual and olfactory cues led to a reduction in the minimum metabolic rate of individuals. Fish held in isolation for 1 week also exhibited a reduction in body condition when compared with those held in shoals. These results indicate that social isolation as a result of environmental disturbance could have physiological consequences for gregarious species.

This study evaluates the swimming behaviour of pre-settled fish larvae of the triplefin Helcogrammoides chil­ensis (Tripterygiidae) in relation to local environmental conditions. Larval aggregations were recorded on rocky reefs off central Chile during the austral summer of 2014 and 2016 to describe their swimming behaviour (i.e. solitary, shoaling, schooling) and relate it to in situ water temperature, wind stress, wind speed and turbulence. Shoaling and solitary behaviour were influenced only by wind-induced turbulence in 2014 and by seawater temperature and wind stress in 2016. Schooling behaviour was not influenced by any of the environmental variables. In situ swimming behaviour of fish larvae has been little investigated, and this work proposes a non-invasive in situ methodology for studying fish larval behaviour.

Zebrafish, a highly-social species of freshwater fish, are widely studied across many fields of laboratory science including developmental biology, neuroscience, and genomics. Nevertheless, as standard housing for zebrafish typically consists of small and simplistic environments, less is known about their social behavioral repertoire in more naturalistic settings. In particular, spontaneously occurring, socio-positive affiliative behaviors (e.g., social coordination and cohesion) that may be indicative of positive emotional experiences have rarely been reported or studied deliberately in zebrafish. Housing adult zebrafish (10 fish/tank) in large semi-natural tanks (110 L; n = 6) with sloping gravel substrate, rocks, and artificial plants, we observed a previously undescribed behavior: Distinct periods of spontaneous, synchronized, compact aggregations, what we call “heightened-shoaling”. This project aimed to quantify the characteristics of this distinctive behavior and compare para...

Nonlinear and dispersive effects are significant for nearshore waves, leading to the study and development of a fully nonlinear and dispersive potential-flow model solving the Euler-Zakharov equations, which determine the temporal evolution of the free surface elevation and velocity potential. The mathematical model and its numerical implementation are presented, as well as the approach chosen to extend the model to two horizontal dimensions. The nonlinear and dispersive capabilities of the 1DH version of the model are demonstrated by applying the model to two test cases: (1) the generation of regular waves created by a piston-like wave maker and the propagation of the associated free and bound harmonics over a flat bottom, following the experiments of CHAPALAIN et al. (1992), and (2) the propagation of irregular waves over a barred beach profile, following the experiments of BECQ-GIRARD et al. (1999). The accuracy of the model in representing high-order nonlinear and dispersive eff...

An extensive dataset combining information obtained from aerial photographs of selected Australian beaches and studies in the literature from a wide variety of sites in Europe, the United States, Japan, South Africa and New Zealand is used to investigate the relationship between rip current spacing on intermediate beaches and regional wave climate. A new parameter termed rip density (RD) is introduced which defines the number of rips per kilometer of beach and is defined as the relationship y r /L r where y r is rip spacing and L r is a nominal length of beach. The variation in rip density was examined for five different regional wave environments termed west coast swell (WCS), east coast swell (ECS), fetch-limited wind wave with strong (SWS) and moderate (MWS) winds, and fetch-limited bays (SWB). Patterns of rip density were extremely consistent between the grouped wave climate environments with WCS beaches characterised by the lowest RD of 2 rips/km and SWB and MWS beaches having ...

Zebrafish are at the forefront of neurobiological research and have been gaining popularity as a viable and valid behavioral model in a variety of research applications (e.g., assessing drug induced behavioral changes). This model becomes even more attractive when considering the behavioral changes that follow exposure to compounds that are water-soluble. As such, several studies have implicated both acute and chronic ethanol exposure in the modulation of zebrafish behavior. Within this arena there appears to be a common trend across multiple studies. As with many drugs ethanol appears to influence behavior in a dose-dependent manner. In this review, we compare and contrast several studies that measure behavior as a result of alcohol exposure. Appended to this review are pilot data that report zebrafish blood alcohol concentrations as a function of acute exposure.

The cues associated with social familiarity and genetic relatedness and how they interact to influence the formation of social associations among individuals, and thus group composition and dynamics, is poorly understood. Here, we investigated the concurrent effects of social familiarity and kinship on social affiliations in free-swimming convict cichlid fish young or ‘fry’ (Amatitlania siquia) by pitting the cues of social familiarity and kinship against each other in a four-way choice apparatus. Individual focal fish were given a simultaneous choice to associate (‘shoal’) with conspecifics that were either socially familiar and kin (full sibs), socially unfamiliar and kin, socially familiar and not kin, or socially unfamiliar and not kin. Stimulus shoal preference differed depending on the body length of the focal fish; smaller fry exhibited no preference, whereas larger (more mobile) fry significantly preferred to associate with familiar kin. In the convict cichlid system, where ...

New open-ocean formulations that define the total wind stress (τtotal) at the air-sea boundary that include contributions from both wind (τwind) and waves (τwave) were evaluated across the wave shoaling region of the inner shelf. Traditional τtotal open ocean formulations have underestimated measured τtotal across the inner shelf. The new formulations spectrally account for the “swell” wave contributions and have been modified to account for the depth (h) dependence of wave shoaling. Swell is defined when phase speed, cp, is greater than 1.14U10, wind speed. The difference between the h-independent, deep-water cp, to the h-dependent cp occurs for U10, <12 m s-1 and h<20m. This defines the parameter space for which swell provides additional contributions across the inner shelf, where the remainder should be described by traditional open-ocean formulations. As cp decreases with decreasing h, swell contribution relative to U10 decreases with decreasing h. Shoaling wave heights re...

This paper presents an investigational study on wave energy converters (WECs). The types of WEC available from the market are studied first. The design considerations for implementing a WEC in the Gulf of Mexico (GOM) are then evaluated. There are several different types of devices that can be used to model the system design. Each device type has different attributes that may be helpful or hurtful for the area and wave activity in the GOM. From the evaluation there is a recommendation of the optimal device design conditions, and three device types are recommended for further pursuit as design candidates. Six different WEC projects that are currently being developed and most are ready for commercial testing are examined. The examination evaluates the usefulness of the WECs for the GOM, and provides some factors of both physical and economic scaling. The result of this study reveals that while none of the devices can be installed “as is” in the GOM because of wave power or geometry re...

In this paper, a nonlinear evolution equation is studied by adding an extra cubic nonlinearity to Ostrovsky equation, known as modified Ostrovsky equation. Ostrovsky equation originally is obtained from Korteweg-de Vries equation with an additional linear non-local term representing the effects of background Earth’s rotation. The addition of rotation term has the drastic effect of destroying the solitary wave solution as an initial wave and eventually form a nonlinear wave packet. We solved this equation using Pseudo-Spectral Method by implementing the dealiasing and sponge-layer techniques. With an additional cubic nonlinear term, an unsteady wave packet is emerged as expected as the linear part is unchanged, however the wave packet is clearly separated from the trailing radiation at the end of the calculation and we observed that the radiated wave is emerged together with the wave packet. This means that the modified Ostrovsky equation leads to the formation of wave packet is fast...