Tagging mortality experiments on Pacific mackerel, Pneumatophorus japonicus

Two experiments were conducted to compare tagging mortality rates when Pacific mackerel are tagged using a traditional method and a modified method. Tagged and control fish in equal numbers were held in tanks on board the R/V ALASKA and observed for mortality. The experiments revealed mortality rates of 24% when the tag passes between the pterygiophores or neural spines and 1.5% when the tag is placed in the lateral musculature. Mortality from handling the fish for tagging was 4%, tank trauma was 2%, and the initial tag loss was 2.5%. (20pp.

Dilation and Asymmetric Relevance

A characterization result of dilation in terms of positive and negative association admits an extremal counterexample, which we present together with a minor repair of the result. Dilation may be asymmetric whereas covariation itself is symmetric. Dilation is still characterized in terms of positive and negative covariation, however, once the event to be dilated has been specified

Dynamic crossover in the persistence probability of manifolds at criticality

We investigate the persistence properties of critical d-dimensional systems relaxing from an initial state with non-vanishing order parameter (e.g., the magnetization in the Ising model), focusing on the dynamics of the global order parameter of a d'-dimensional manifold. The persistence probability P(t) shows three distinct long-time decays depending on the value of the parameter \zeta = (D-2+\eta)/z which also controls the relaxation of the persistence probability in the case of a disordered initial state (vanishing order parameter) as a function of the codimension D = d-d' and of the critical exponents z and \eta. We find that the asymptotic behavior of P(t) is exponential for \zeta > 1, stretched exponential for 0 <= \zeta <= 1, and algebraic for \zeta < 0. Whereas the exponential and stretched exponential relaxations are not affected by the initial value of the order parameter, we predict and observe a crossover between two different power-law decays when the algebraic relaxation occurs, as in the case d'=d of the global order parameter. We confirm via Monte Carlo simulations our analytical predictions by studying the magnetization of a line and of a plane of the two- and three-dimensional Ising model, respectively, with Glauber dynamics. The measured exponents of the ultimate algebraic decays are in a rather good agreement with our analytical predictions for the Ising universality class. In spite of this agreement, the expected scaling behavior of the persistence probability as a function of time and of the initial value of the order parameter remains problematic. In this context, the non-equilibrium dynamics of the O(n) model in the limit n->\infty and its subtle connection with the spherical model is also discussed in detail.Comment: 23 pages, 6 figures; minor changes, added one figure, (old) fig.4 replaced by the correct fig.

Results of the jack mackerel subpopulation discrimination feasibility study

A report is made on the feasibility of discriminating subpopulations of jack mackerel, Trachurus symmetricus, off of the southern California and Baja California coast. Histochemical, morphometric, and meristic characters are compared from four samples of approximately 200 fish each taken from three areas. The data are analyzed for homogeneity by chi-square tests. Heterogeneity was found only in anal fin ray counts. Recommendations for a comprehensive study are made. (16pp.