Browsing by Author "Stratoudakis, Yorgos"
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- Contributions towards maritime spatial planning (MSP) in Portugal - Conference reportPublication . Ferreira, Maria Adelaide; Silva, Carlos Pereira da; Fonseca, Catarina; Pereira, Margarida; Calado, Helena; Abreu, António Domingos; Andrade, Francisco; Guerreiro, José; Gonçalves, Emanuel João; Noronha Filho, Francisco Áureo; Lopes, Carlos Pinto; Ribeiro, Marta Chantal; Stratoudakis, Yorgos; Vasconcelos, LiaThis contribution summarizes the main concerns presented by experts at a conference held in Lisbon in January 2015 to discuss the developing Portuguese legal framework for MSP and lists the suggestions that were correspondingly offered on how to improve the proposed framework.
- Differences in sounds made by courting males of three closely related Lake Malawi cichlid speciesPublication . Amorim, Maria Clara Pessoa; Knight, Mairi E.; Stratoudakis, Yorgos; Turner, George F.Courtship sounds made by three sympatric cichlid species, Pseudotropheus zebra, P. callainos and an undescribed species known as P. ‘zebra gold’ were recorded and compared to investigate the potential role of acoustic signals in mate choice. Sounds were emitted during ‘quiver’ and ‘circle’ components of the male courtship display and consisted of rapidly repeated pulse units. Some sound variables differed significantly among species with P. callainos generally being separated from the other two species. This species produced sounds with higher peak frequency (for a given length) and lower number of pulses than P. ‘zebra gold’ and higher pulse durations than P. zebra. In addition, standard length was inversely related to peak frequency in both P. ‘zebra gold’ and P. callainos (this relation was not tested in P. zebra due to the small sample size). These differences might indicate different regimes of intraspecific sexual selection among the three species.
- Sound production during competitive feeding in the grey gurnardPublication . Amorim, Maria Clara Pessoa; Stratoudakis, Yorgos; Hawkins, Anthony D.The acoustic repertoire of captive grey gurnard Eutrigla gurnardus during competitive feeding consisted of three types of sound: knocks, grunts and growls. Knocks were audible as a single sound, whereas grunts and growls were perceived as longer, pulsed sounds to the human ear. Typically, knocks were composed of 1–2 pulses, grunts of 4–8 pulses and growls >10 pulses. Growls were longer and had shorter pulse periods than grunts. All sound types had peak frequencies of c. 500 Hz. The sequences of behaviours observed during feeding interactions suggest that grey gurnard obtain food both by scramble and contest tactics. Competing fish emitted knocks mainly while grasping a food item and also during other non-agonistic behaviour, suggesting that knock production may reflect a state of feeding arousal but could also serve as a warning of the forager’s presence to nearby competitors. Grunts were mainly emitted during frontal displays, which were the most frequent behavioural act preceding grasps, suggesting that they may play a role in deterring other fish from gaining access to disputed food items.