A Synthesis of Tagging Studies Examining the Behaviour and Survival of Anadromous Salmonids in Marine Environments

This paper synthesizes tagging studies to highlight the current state of knowledge concerning the behaviour and survival of anadromous salmonids in the marine environment. Scientific literature was reviewed to quantify the number and type of studies that have investigated behaviour and survival of anadromous forms of Pacific salmon (Oncorhynchus spp.), Atlantic salmon (Salmo salar), brown trout (Salmo trutta), steelhead (Oncorhynchus mykiss), and cutthroat trout (Oncorhynchus clarkii). We examined three categories of tags including electronic (e.g. acoustic, radio, archival), passive (e.g. external marks, Carlin, coded wire, passive integrated transponder [PIT]), and biological (e.g. otolith, genetic, scale, parasites). Based on 207 papers, survival rates and behaviour in marine environments were found to be extremely variable spatially and temporally, with some of the most influential factors being temperature, population, physiological state, and fish size. Salmonids at all life stages were consistently found to swim at an average speed of approximately one body length per second, which likely corresponds with the speed at which transport costs are minimal. We found that there is relatively little research conducted on open-ocean migrating salmonids, and some species (e.g. masu [O. masou] and amago [O. rhodurus]) are underrepresented in the literature. The most common forms of tagging used across life stages were various forms of external tags, coded wire tags, and acoustic tags, however, the majority of studies did not measure tagging/handling effects on the fish, tag loss/failure, or tag detection probabilities when estimating survival. Through the interdisciplinary application of existing and novel technologies, future research examining the behaviour and survival of anadromous salmonids could incorporate important drivers such as oceanography, tagging/handling effects, predation, and physiology

Epicuticular waxes from caatinga and cerrado species and their efficiency against water loss

The effects of the contents and chemical composition of the foliar epicuticular waxes of species from the caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) and cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) were evaluated as to the resistance to water loss by means of an experimental device constructed for this purpose. In general, the waxes of the caatinga species investigated were more efficient against water loss than cerrado species. Increase of the thickness of the waxy deposits from 40 to 90m g.cm-2 had no significant effect on the resistance to water loss. The chemistry of the wax constituents was shown to be an important factor to determine the degree of resistance to evaporation. n-Alkanes and alcoholic triterpenes were the most efficient barriers, while hentriacontan-16-one (a ketone) and ursolic acid (an acid triterpene) revealed lowefficiency. The higher efficiency of the waxes of the leaves from caatinga species (mainly those of C. yco and Z. joazeiro) is probably accounted for the predominance of n-alkanes in their composition. The lower efficiency of the waxes of A. pyrifolium (caatinga), T. formosa and A. esperanzae (both species from the cerrado) is probably a consequence of the predominance of triterpenoids in the waxes of the two former species and hentriacontan-16-one in the latter.<br>A influência do teor e da composição química das ceras epicuticulares foliares de espécies da caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida e Ziziphus joazeiro) e do cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina e Tocoyena formosa) foram avaliadas em relação à resistência à perda de água, através de um dispositivo experimental construído para essa finalidade. Em geral, as ceras das espécies da caatinga foram mais eficientes contra a perda de água que as das espécies do cerrado. O aumento da espessura dos depósitos cerosos de 40 até 90 mg.cm-2 não alterou significativamente a resistência à evaporação. A natureza química dos componentes das ceras revelou-se um fator importante na determinação do grau de resistência à evaporação. n-Alcanos e triterpenos alcoólicos foram os constituintes mais eficientes como barreiras à evaporação, enquanto hentriacontan-16-ona (uma cetona) e ácido ursólico (triterpeno com função carboxílica) foram menos eficazes. A maior eficiência das ceras epicuticulares de duas espécies da caatinga (C. yco e Z. joazeiro) provavelmente se deve à predominância de n-alcanos em sua composição. A menor eficiência das ceras epicuticulares de A. pyrifolium (outra espécie da caatinga), T. formosa e A. esperanzae (ambas espécies do cerrado), à predominância em suas ceras de ácido ursólico para as duas primeiras e hentriacontan-16-para a última