نتایج جستجو برای: scallop
تعداد نتایج: 1556 فیلتر نتایج به سال:
The results of fishery investigations are used to estimate the catch size, times fish are caught, and future stocks in the fish culture industry. In Tokoro, Japan, scallop farms for fisheries are found on gravel and sand seabeds. The seabed images are used for fishery investigations, which are absolutely necessary to visually estimate the amount of scallops. However, there is no automatic techn...
Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of all 11 great sharks that consume other elasmobranchs (rays, skates, and small sharks) fell over the past 35 years, 12 of 14 of these prey species increased in coastal northwest Atlantic ecosystems....
To achieve propulsion at low Reynolds number, a swimmer must deform in a way that is not invariant under time-reversal symmetry; this result is known as the scallop theorem. However, there is no many-scallop theorem. We demonstrate here that two active particles undergoing reciprocal deformations can swim collectively; moreover, polar particles also experience effective long-range interactions....
Recently, the investigation method has been developed to measure fishes using an underwater video camera. These methods can investigate the benthic fishery resources, but the acoustic survey cannot. However, these investigations do not use automatic measurements from the videos but only taken the videos. In this paper, we propose a method to count the scallop and the asteroid from the seabed vi...
Experimental scallop fishing was carried out using towed commercial dredges on sediments deposited by unattached coralline algae in order to quantify their sensitivity to damage from current fishing practices. These biogenic sediments are patchily distributed in European coastal waters (to -30 m depth around the UK and to -120 m in the Mediterranean) and are of international conservation import...
Anthropogenic impacts are endangering many long-lived species and lineages, possibly leading to a disproportionate loss of existing evolutionary history (EH) in the future. However, surprisingly little is known about the loss of EH during major extinctions in the geological past, and thus we do not know whether human impacts are pruning the tree of life in a manner that is unique in the history...
Seasonality, amplitude, and magnitude of spawning events were determined for Argopecten purpuratus in the La Rinconada marine reserve, Antofagasta, Chile, between December 1995 and January 2004. During the same period, samples of scallop larvae were obtained in vertical plankton hauls recovered within this reserve in an area routinely exposed to circular, gyre-like currents which helped retain ...
An important question in evolutionary biology is how often, and to what extent, do similar ecologies elicit distantly related taxa to evolve towards the same phenotype? In some scenarios, the repeated evolution of particular phenotypes may be expected, for instance when species are exposed to common selective forces that result from strong functional demands. In bivalved scallops (Pectinidae), ...
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