– in this paper we consider some (α ,β ) -metrics such as generalized kropina, matsumoto and f (α β )2α = + metrics, and obtain necessary and sufficient conditions for them to be einstein metrics when βis a constant killing form. then we prove with this assumption that the mentioned einstein metrics must beriemannian or ricci flat.

The aims of this study were first, to test the hypothesis that metrics of fish growth and condition relate positively to parasite species richness (S(R)) in a salmonid host; second, to identify whether S(R) differs as a function of host origin; third, to identify whether acquisition of parasites through marine v. freshwater trophic interactions was related to growth and condition of juvenile sa...

Two major air-gun exposure experiments have been conducted in Norwegian waters: The Nordkappbank experiment in 1992 [Can. J. Fish. Res. Aq. Sci., 1996, Vol. 53, pp. 2238-2249] and the Vesterålen experiment in 2009 [Fisken og Havet, 2010, Nr. 2, 76 pp. Inst. of Mar. Res.]. Although changes in catch rates and distribution of fish were observed in both cases, the responses were higher in the first...

Identifying the most sensitive indicators to changes in fishing pressure is important for accurately detecting impacts. Biomass is thought to be more sensitive than abundance and length, while the wariness of fishes is emerging as a new metric. Periodically harvested closures (PHCs) that involve the opening and closing of an area to fishing are the most common form of fisheries management in th...

Global warming scenarios combined with political and public awareness have led to increasing funding and research efforts on the measurement and prediction of effects of a changing world on the ecosystems. Fish parasites represent a major part of aquatic biodiversity, and consequently become affected either directly through the environment or indirectly through their respective hosts. On the ba...

BACKGROUND Aerosolization of seafood and subsequent inhalation, during processing is a potential high-risk activity for allergic respiratory disease. OBJECTIVES To quantify total thoracic particulate, protein concentration and specific fish (pilchard, anchovy) antigen concentrations in fish processing plants; to determine the correlation between these exposure metrics; and to identify the maj...

While differences in individual personality are common in animal populations, understanding the ecological significance of variation has not yet been resolved. Evidence suggests that personality may influence learning and memory; a finding that could improve our understanding of the evolutionary processes that produce and maintain intraspecific behavioural heterogeneity. Here, we tested whether...

We investigated whether fish assemblage structure in southern Appalachian streams differed with historical and contemporary forest cover. We compared fish assemblages in 2(nd)-4(th) order streams draining watersheds that had increased forest cover between 1950 and 1993 (i.e., reforesting watersheds). We sampled fish in 50 m reaches during August 2001 and calculated catch-per-unit-effort (CPUE) ...

the general relatively isotropic mean landsberg metrics contain the general relativelyisotropic landsberg metrics. a class of finsler metrics is given, in which the mentioned two conceptsare equivalent. in this paper, an interpretation of general relatively isotropic mean landsberg metrics isfound by using c-conformal transformations. some necessary conditions for a general relativelyisotropic ...

Anthropogenic disturbances are ubiquitous in the ocean, but their impacts on marine species are hotly debated. We evaluated marine fish statuses using conservation (Red List threatened or not) and fisheries (above or below reference points) metrics, compared their alignment, and diagnosed why discrepancies arise. Whereas only 13.5% of Red Listed marine fishes (n = 2952) are threatened, 40% and ...