Impacts of climate change and variability on fish value chains in Uganda

This study examines the vulnerability of fish pr oduction in Uganda, particularly as it r elates to the predicted impacts from climate change, using the concept of the value chain. The value chain approach has been recommended as a useful tool to study specific challenges facing a sector resulting from various drivers of change, including climate. Critically, such analyses can reveal context-specific response strategies to enhance a sector (Jacinto and Pomer oy 2010). The specific purpose of the study was to identify curr ent and potential impacts of climate change and corresponding adaptation strategies in fish value chains. The study builds upon information fr om earlier value chain analyses on fisheries and aquaculture production in Uganda to provide a more in-depth understanding of issues facing the fish industry, in particular, those to be incorporated in the CGIAR Resear ch Program Livestock and Fish.

Biological characteristics and mortality of western butterfish (Pentapodus vitta), an abundant bycatch species of prawn trawling and recreational fishing in a large subtropical embayment

The western butterfish (Pentapodus vitta) is numerous in the bycatch of prawn trawling and recreational fishing in Shark Bay, Western Australia. We have thus determined crucial aspects of its biological characteristics and the potential impact of fishing on its abundance within this large subtropical marine embayment. Although both sexes attained a maximum age of 8 years, males grow more rapidly and to a larger size. Maturity is attained at the end of the first year of life and spawning occurs between October and January. The use of a Bayesian approach to combine independent estimates for total mortality, Z, and natural mortality, M, yielded slightly higher point estimates for Z than M. This result indicates that P. vitta is lightly impacted by fishing. It is relevant that, potentially, the individuals can spawn twice before recruitment into the fishery and that 73% of recreationally caught individuals are returned live to the water.

Variability in supply and cross-shelf transport of pink shrimp (Farfantepenaeus duorarum) postlarvae into western Florida Bay

The variability in the supply of pink shrimp (Farfantepenaeus duorarum) postlarvae and the transport mechanisms of planktonic stages were investigated with field data and simulations of transport. Postlarvae entering the nursery grounds of Florida Bay were collected for three consecutive years at channels that connect the Bay with the Gulf of Mexico, and in channels of the Middle Florida Keys that connect the southeastern margin of the Bay with the Atlantic Ocean. The influx of postlarvae in the Middle Florida Keys was low in magnitude and varied seasonally and among years. In contrast, the greater postlarval influx occurred at the northwestern border of the Bay, where there was a strong seasonal pattern with peaks in influx from July through September each year. Planktonic stages need to travel up to 150 km eastward between spawning grounds (northeast of Dry Tortugas) and nursery grounds (western Florida Bay) in about 30 days, the estimated time of planktonic development for this species. A Lagrangian trajectory model was developed to estimate the drift of planktonic stages across the SW Florida shelf. The model simulated the maximal distance traveled by planktonic stages under various assumptions of behavior. Simulation results indicated that larvae traveling with the instantaneous current and exhibiting a diel behavior travel up to 65 km and 75% of the larvae travel only 30 km. However, the eastward distance traveled increased substantially when a larval response to tides was added to the behavioral variable (distance increased to 200 km and 85% of larvae traveled 150 km). The question is, when during larval development, and where on the shallow SW Florida shelf, does the tidal response become incorporated into the behavior of pink shrimp.

Biochemical biomarkers in samples processed by different methods in Environmental Specimen Banks

In the last decades the creation of new Environmental Specimen Banks (ESB) is increasing due to the necessity of knowing the effects of pollutants in both the environment and human populations. ESBs analyze and store samples in order to understand the effects of chemicals, emerging substances and the environmental changes in biota. For a correct analysis of the effect induced by these variables, there is a need to add biological endpoints, such as biomarkers, to the endpoints based on chemical approaches which have being used until now. It is essential to adapt ESB´s sampling strategies in order to enable scientists to apply new biological methods. The present study was performed to obtain biochemical endpoints from samples stored in the BBEBB (Biscay Bay Environmental Biospecimen Bank) of the Marine Station of Plentzia (PIE - UPV/EHU). The main objective of the present work was to study the variability caused in biochemical biomarkers by different processing methods in mussels (Mytilus galloprovincialis) from two localities (Plentzia and Arriluze) with different pollution history. It can be concluded that the selected biomarkers (glutathione S-transferase and acetylcholinesterase) can be accurately measured in samples stored for years in the ESBs. The results also allowed the discrimination of both sampling sites. However, in a further step, the threshold levels and baseline values should be characterized for a correct interpretation of the results in relation to the assessment of the ecosystem health status.

Impacto de las aguas residuales urbanas sobre las comunidades de macroalgas intermareales: caso practico en la Reserva de la Biosfera de Urdaibai

[ES] Las aguas residuales domésticas asociadas a los núcleos urbanos se encuentran entre los principales impactos antrópicos que amenazan la biodiversidad de los ecosistemas costeros. El presente trabajo tiene como objetivo evaluar el impacto de aguas residuales provenientes de la población de Bermeo sobre las comunidades intermareales de la parte mas externa de la Reserva de la Biosfera de Urdaibai. Para ello se ha contrastado la estructura de la vegetación bajo la influencia del emisario con la existente en cuatro localidades control en los años 2013 y 2014. Los resultados reflejan diferencias en la composición de la flora intermareal entre la localidad impactada y las localidades no afectadas por la contaminación. La localidad impactada queda caracterizada por la proliferación de algas filamentosas (Bachelotia antillarum) y clorófitos (Ulva intestinalis), así como de rodofíceas cespitosas con corticación simple (Gellidium pusillum, Gellidium pulchellum y Caulacanthus ustulatus). Por el contrario, en las localidades control son abundantes las especies perennes de gran porte y morfología compleja (Bifurcaria bifurcata, Cystoseira tamariscifolia, Halopteris spp. y Gelidium corneum). La calcárea Coralina elongata, estaba presente tanto en las localidades control como en la localidad impactada. Por otra parte, los análisis de la varianza realizados detectaron una elevada variabilidad espacio-temporal en la composición multivariable de la vegetación intermareal de las estaciones control, lo cual restó poder estadístico para detectar las diferencias entre la localidad impactada y los controles. Este resultado pone de manifiesto la dificultad e importancia de elegir controles apropiados para detectar impactos ambientales. Este estudio ha proporcionado la información necesaria sobre el estado ecológico de las comunidades en la situación pre-operacional de la EDAR de Lamiaran (Bermeo), lo cual permitirá evaluar en un futuro la eficacia del tratamiento de las aguas en términos de recuperación biológica.

The half-lives of biological activity of some pesticides in water

In the absence of analytical methods, the half-lives of biological activity of pesticides can be estimated by bioassays. To determine the half-lives of biological acivity of pesticides to fish, static bioassays were conducted in the laboratory with ten different formulations of pesticides using Labeo rohita as a bio-indicator. The half-lives of biological activity for ten different pesticides in soft water at pH 7.5 and 27°C, ranged from 4.6 days to 11.8 days. The half-life of biological activity of Sumithion 50% EC was only 4.6 days. In contrast, Dimecron 50% EC degraded very slowly and its half-life of biological activity on L. rohita was about 11.8 days. Sumithion 50% EC, Padan 50% SP, EPN 45% EC, Diazinon 40% EC and Diazinon 10 G degraded in less than five to seven days indicating that these pesticides are desirable for rice-fish culture. Contamination by pesticides with long-term residual toxicity in waters may eventually cause high levels of fish mortality.

Life cycle and biological parameters of several Brazilian Amazon fish species

This contribution summarizes knowledge on the biology (population dynamics, reproduction, ecology) of 25 fish species from the Lower Amazon, Brazil, based on data from a Brazilian-German field project (IARA) and a review of the literature.

Sources of variability in the free-ball micro-scale abrasion test

In the 'free-ball' version of the micro-scale abrasion or ball-cratering test the rotating ball rests against a tilted sample and a grooved drive shaft. Tests under nominally identical conditions with different apparatus commonly show small but significant differences in measured wear rate. An indirect method has been developed and demonstrated for continuous on-line measurement of the coefficient of friction in the free-ball test. Experimental investigation of the effects of sample tilt angle and drive shaft groove width shows that both these factors influence the stability of the rotation of the ball, and the shape of the abrasive slurry pool, which in turn affect the coefficient of friction in the wear scar area and the measured wear rate. It is suggested that in order to improve the reproducibility of this method the geometry of the apparatus should be specified. For the apparatus used in this work with a steel ball of 25 mm diameter, a sample tilt angle of 60-75° and a shaft groove width of about 10mm provided the most stable ball motion and a wear rate which showed least variability. © 2004 Elsevier B.V. All rights reserved.