Shrinking Fish By
نویسندگان
چکیده
Fisheries scientist David Conover, dean and director of the Marine Sciences Research Center at SUNY Stony Brook, is leading the most extensive laboratory study to date on the effects of size-selective harvesting in fish stocks. As described in Scientific American magazine, he and his team mimicked fishing by removing 90 percent of the largest fish from a lab population of Atlantic Siversides (Menidia menidia), a small marine fish. In another experimental group they removed 90 percent of the smallest fish, and in a control group they removed the same amount of fish, but without regard to size.
منابع مشابه
Fish: A Fast Software Stream Cipher
Coppersmith, Krawczyk, and Mansour ([CKM93]) presented at Crypto '93 a promising stream cipher, the shrinking generator. It is based on linear shift registers with linear feedback. The output bits of one shift register decide which of the output bits of the other shift registers are used and which are discarded. The design is well suited for hardware implementation. In software shift registers ...
متن کاملEcological consequences of body size decline in harvested fish species: positive feedback loops in trophic interactions amplify human impact.
Humans are changing marine ecosystems worldwide, both directly through fishing and indirectly through climate change. One of the little explored outcomes of human-induced change involves the decreasing body sizes of fishes. We use a marine ecosystem model to explore how a slow (less than 0.1% per year) decrease in the length of five harvested species could affect species interactions, biomasses...
متن کاملConversion and Residence Time Calculation for Gas-solid Solid Reactions of the Cylindrical-shaped Particles with Con-stant Size Using the Shrinking Core Model
In this paper, a mathematical model is developed to calculate the conversion and the residence time reaction for plug flow and mixed flow in the reactors filled with cylin-drical particles using the shrinking core model. In this modeling, the size of the particles is un-chamged during the reaction. Also, the reaction rate is controlled by the gas layer resistance, the ash layer resistance, and ...
متن کاملMagnetohydrodynamics Fluid Flow and Heat Transfer over a Permeable Shrinking Sheet with Joule dissipation: Analytical Approach
A laminar, two dimensional, steady boundary layer Newtonian conducting fluid flow passes over a permeable shrinking sheet in the presence of a uniform magnetic field is investigated. The governing equations have converted to ordinary nonlinear differential equations (ODE) by using appropriate similarity transformations. The main idea is to transform ODE with infinite boundary condition into oth...
متن کاملShrinking fish: comparisons of prehistoric and contemporary salmonids indicate decreasing size at age across millennia
A comparison of Upper Palaeolithic and contemporary salmonid vertebrae from the Iberian Peninsula indicates that there has been a significant decrease in the mean body size for a given age among Atlantic salmon and brown trout inhabiting the southernmost range of their endemic distribution. Mean size at age was greater in prehistoric specimens for all age classes during the freshwater phase of ...
متن کامل