Loading...
Publication
Long-snouted seahorse, Hippocampus guttulatus, behaviour and physiology under global warming
Advisor(s)
Abstract(s)
Os oceanos fornecem serviços inestimáveis ao planeta. A libertação de CO2 para a
atmosfera desde a Revolução Industrial levou à aceleração das alterações climáticas,
aumentando a temperatura da atmosfera e dos oceanos. Para os organismos ectotérmicos, como
os peixes, a temperatura é um fator determinante para vários processos comportamentais,
fisiológicos, e metabólicos, que são otimizados dentro de uma gama limitada de temperaturas.
A compreensão de como o aquecimento dos oceanos terá impacto nestas espécies é, portanto,
da maior relevância para fins de gestão e conservação. O objetivo deste trabalho consistiu em
avaliar os efeitos do aquecimento no crescimento, taxas de ingestão e comportamento do
cavalo-marinho, Hippocampus guttulatus. Os indivíduos foram recolhidos antes da época de
reprodução, no estuário do Sado, e expostos durante um período de 8 semanas a três
temperaturas diferentes: 17ºC, 20ºC e 24ºC. Três vezes por semana, foram realizadas
observações comportamentais. A taxa de ingestão foi contabilizada diariamente e os indivíduos
pesados uma vez por semana. Os resultados do presente estudo indicam diferenças nas respostas
comportamentais e fisiológicas dos cavalos-marinhos expostos a condições de aquecimento
durante um período de longa duração (8 semanas). Em condições de temperatura extrema (24
ºC), os peixes estavam mais ativos, alimentavam-se mais, mas este aumento de energia através
da alimentação não se traduziu num aumento de peso. No conjunto, estes dados podem indicar
que esta população de cavalos-marinhos pode vir a estar sob stress térmico quando expostos,
por um longo período, a condições de aquecimento que se esperam no final do século
The oceans provide inestimable services to the planet. The continuous CO2 release to the atmosphere since the Industrial Revolution, have led to the acceleration of climate change, with emphasis on the increase of the atmosphere and oceans’ temperature. Ocean warming will impact marine organisms at several levels. For ectotherms, such as fish, temperature is a determinant cue for several behavioural, physiological, and metabolic processes, which are optimized to take place within a limited temperature range. Understanding of how ocean warming will impact species is, therefore, of utmost relevance for management and conservation purposes. Here, we aimed to assess the effects of ocean warming on growth, feed intake, and behavioural patterns, including courtship and reproduction, of the long-snouted seahorse, Hippocampus guttulatus. Fish were collected, prior the breeding season, in the Sado estuary, and subsequently exposed for an 8-week period to three different temperatures: 17ºC, 20ºC and 24ºC. Three times a week, behavioural observations were performed. Feed intake was measured every day and individuals weighted once a week. Results from the present study indicate differences in behavioural and physiological responses in seahorses exposed to increasingly warming conditions. Under extreme temperature conditions (24 ºC), fish were more active, fed more, but this increment of energy through feeding did not translate into increased growth in weight. Altogether, these data may indicate that Sado’s wild population of long-snouted seahorse may become under thermal stress when exposed, for a long term, to warming conditions that are expected to occur in the end of the century.
The oceans provide inestimable services to the planet. The continuous CO2 release to the atmosphere since the Industrial Revolution, have led to the acceleration of climate change, with emphasis on the increase of the atmosphere and oceans’ temperature. Ocean warming will impact marine organisms at several levels. For ectotherms, such as fish, temperature is a determinant cue for several behavioural, physiological, and metabolic processes, which are optimized to take place within a limited temperature range. Understanding of how ocean warming will impact species is, therefore, of utmost relevance for management and conservation purposes. Here, we aimed to assess the effects of ocean warming on growth, feed intake, and behavioural patterns, including courtship and reproduction, of the long-snouted seahorse, Hippocampus guttulatus. Fish were collected, prior the breeding season, in the Sado estuary, and subsequently exposed for an 8-week period to three different temperatures: 17ºC, 20ºC and 24ºC. Three times a week, behavioural observations were performed. Feed intake was measured every day and individuals weighted once a week. Results from the present study indicate differences in behavioural and physiological responses in seahorses exposed to increasingly warming conditions. Under extreme temperature conditions (24 ºC), fish were more active, fed more, but this increment of energy through feeding did not translate into increased growth in weight. Altogether, these data may indicate that Sado’s wild population of long-snouted seahorse may become under thermal stress when exposed, for a long term, to warming conditions that are expected to occur in the end of the century.
Description
Dissertação de Mestrado apresentada no ISPA – Instituto
Universitário para obtenção de grau de Mestre
na especialidade de Biologia Marinha e
Conservação
Keywords
Comportamento Alterações climáticas Hippocampus guttulatus Fisiologia Cavalos-marinhos Behaviour Climate change Seahorses