Evaluating the effectiveness of teeth and dorsal fin spines for non-lethal age estimation of a tropical reef fish, coral trout Plectropomus leopardus

This study investigated whether teeth and dorsal fin spines could be used as non-lethal methods ofage estimation for a vulnerable and highly valued tropical fisheries species, coral trout Plectropomus leopardus. Age estimation of individuals from 2 to 9 years old revealed that dorsal spines represent an accurate ageing method (90% agreement with otoliths) that was more precise [average per cent error (APE)=4·1, coefficient of variation (c.v.)=5·8%] than otoliths (APE = 6·2, c.v. = 8·7%). Of the three methods for age estimation (otoliths, dorsal spines and teeth), spines were the most time and cost efficient. An aquarium-based study also found that removing a dorsal spine or tooth did not affect survivorship or growth of P. leopardus. No annuli were visible in teeth despite taking transverse and longitudinal sections throughout the tooth and trialling several different laboratory methods. Although teeth may not be suitable for estimating age of P. leopardus, dorsal spines appear to be an acceptably accurate, precise and efficient method for non-lethal ageing of individuals from 2 to 9 years old in this tropical species

Estimación a corto plazo de la temperatura del agua. Aplicación en sistemas de producción en medio acuático

[ES] El control y la predicción de parámetros físico-químicos del agua en tanques de cultivo de plantas de producción en medio acuático es un aspecto fundamental del buen funcionamiento de este tipo de instalaciones. En este trabajo se propone la estimación de la temperatura del agua en las próximas 24 horas en una planta de producción de anguilas europeas de carácter intensivo mediante regresiones múltiples y modelos univariantes de series temporales (modelos de suavizado y ARIMA). Se cuenta con datos de las temperaturas diarias en distintas series de tanques correspondientes a los años 1997 al 2001. Los modelos se calibran considerando exclusivamente la relación de los datos presentes y pasados de la temperatura, asumiéndose de esta forma que la variabilidad de otros factores que pueden influir en este parámetro está contenida en la propia serie de datos. 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Obstacles to executive coaching during planned radical organisational change

There is currently limited research on either coaching in organisations or executive coaching in Planned Radical Organisational Change (PROC). The research that does exist on these subjects focuses primarily on whether coaching is considered efficacious, and there has been no research on the obstacles preventing the adoption of executive coaching to assist divisional, functional and central leaders during PROC as part of change implementation programmes. The primary aim of this research was to uncover the reasons why executive coaching is not used in these situations, including whether some senior PROC leaders may block such investment because they are Machiavellian or not change-ready. The research uses a mixed-method design. Two hundred and sixty-two high-ranking executives were surveyed on their attitude towards executive coaching, their Machiavellianism and their change-readiness. Details about their previous roles in PROC, their rank and current employer were also collected. Nearly half of these leaders were in organisations with more than 10,000 employees and over three-quarters in organisations of more than 1,000. Over three-quarters were chief officers or directors. Hierarchical regression was used to create three models to understand the relationship of these variables with the attitude of senior executives towards coaching. Quantitative analysis informed the next step of the sequential mixed method, and 12 executives were interviewed. These were systematically chosen from the survey respondents, based on their Machiavellianism score and role in PROC. These semi-structured interviews examined the results from the survey analysis and other potential issues relating to the procurement of coaching. Qualitative analysis was used to uncover underlying themes from interview transcripts. The quantitative and qualitative elements were then synthesised. A key qualitative finding was the belief among senior executives that, although coaching was valuable for an individual, its benefits for the organisation could not be quantified and, thus, any predicted return on investment was not reliable or credible. They found it impossible, therefore, to put forward or approve business cases for significant coaching investment as a routine part of change programmes. Another key finding, in both the quantitative and qualitative results, was that Machiavellianism and low levels of change readiness in PROC leaders are associated with less favourable attitudes towards executive coaching in PROC. This research adds to the discussion by finding that, although coaching is often considered efficacious by executives, as suggested by previous coaching researchers, there are still significant obstacles to its widespread adoption in PROC. This research contradicted the prevailing view that return on investment is either not relevant to coaching or has been accepted as having been proved sufficiently for those people preparing or approving business cases. It enhances the theoretical knowledge of executive coaching during PROC by producing a diagram of the obstacles to executive coaching procurement in PROC situations. This research has particular relevance to coaching practice, including to Executive Coaches and HR directors. With an increasing number of organisations restructuring following disruptions caused by technology changes and the recent pandemic, overcoming obstacles, including more coaching in change programmes and improving the PROC success rate are important to individual companies and the economy. This research had further value due to the involvement of very senior business executives, a population not greatly researched in large sample sizes in the coaching field, due to the difficulties in gaining access on this scale