Effect of incubation and rearing temperatures on white muscle growth of the common dentex Dentex dentex (Linnaeus, 1758)

In order to determine the impact of temperature on axial muscle growth of common dentex Dentex dentex (Linnaeus, 1758) eggs from the same spawn were divided into four batches and reared under different temperature combinations. The cross-sectional area of white muscle and the number and average area of the white muscle fibres were quantified at different stages of larval development. Our results show that, in newly hatched larvae, slight changes in incubation temperature (≈ 2 ºC) produced significant differences in the cross-sectional area of white muscle, which was greater in the group incubated at ambient temperature. As the larval development advanced, the muscle growth parameters showed the highest values in larvae maintained in constantly heated water.Se pretende valorar el efecto de la temperatura sobre el crecimiento de la musculatura axial del dentón Dentex dentex (Linnaeus, 1758). Para ello se incubó una puesta distribuida en cuatro lotes que fueron sometidos a combinaciones de temperatura. En distintos momentos del desarrollo larvario se cuantificó el área total del miotomo, el área de las fibras blancas y el número de fibras blancas de la sección transversal. Los resultados han demostrado que modificaciones pequeñas en la temperatura de incubación (≈ 2 ºC) producen diferencias significativas en el área transversal total del músculo blanco de las larvas recién eclosionadas, diferencias que son mayores en los ejemplares incubados a temperatura ambiente. A medida que avanza el desarrollo de las larvas se produce una inversión y pasan a ser mayores los parámetros de crecimiento muscular en las larvas mantenidas siempre en agua que es calentada.Instituto Español de Oceanografí

Identification of the vertical plane motion model of a high speed craft by model testing in irregular waves

Experiments in towing tanks are concerned with the determination of the motion transfer functions, which are obtained by testing in irregular waves. For this purpose a model of pitch and heave motions has been developed, and the identified models of the vertical plane motions of a high-speed craft are showed. Linear models are obtained for different sea states and ship speeds. A general low order model is obtained by pole-zero cancellation. So, a full model may be considered for simulation and verification, and a low order model for design. From the lowest order models, a state space model is obtaine