Fish movements and behaviours in complex landscapes
How fish move in complex landscapes? Functional connectivity from a reef fish perspective
Coral reefs landscape configuration
In complex landscapes, structural and social habitat features may impede or facilitate animal movement and may act as limiting factors to immigration. However, different species view the landscape very differently. Functional connectivity - the degree to which the landscape facilitates or impedes movement - depends on how animals perceive costs and benefits associated with habitat features and integrate them into a movement path. We examined how open sand areas and conspecific distribution affected functional connectivity from a damselfish fish perspective (Turgeon et al. 2010). We also observed sand gap crossing ability in parrotfishes and realized that their acknowledged high mobility is likely overestimated...
Factors limiting fish distribution, abundance and diversity
A squirrelfish, using its diurnal shelter
Many fish species spend all or much of their time closely associated
with physical structure, such as clusters
of algae, plants or coral, under rocks or in shells,
caves, holes or the interstitial spaces of rubble. These “shelters”,
may reduce predation risk, may provide feeding and
reproduction sites and may offer protection from strong currents.
For these reasons, shelters may be a limiting resource for coral reef fishes. We examined microhabitat shelter use by Holocentrus rufus, a squirrelfish, and provide
evidence of selectivity of refuges (see Ménard et al. 2008, for additional details). On a larger scale experiment, we quantified the abundance of shelters and estimated
shelters availability on two reefs and explored how shelters
abundance and availability relates to physical characteristics of the reefs and examined how
abundance and availability affect the abundance, occupancy and species richness
of shelter-using fish (see Ménard et al. 2012).
Juvenile salmonid fish on its "home rock"
During my master degree, I compared the capacity of logistic regression and classification tree models to predict microhabitat use of active (i.e. feeding fish) and resting fish juvenile Atlantic salmon, Salmo salar, in a small stream in eastern Quebec (Gaspesia Peninsula). We found that the spatial distribution of active fish differed markedly from that of resting fish, apparently as a result of the selection for water greater than about 30 cm depth by active fish and for the presence of rocky cover by resting fish. Large rocks are likely to be a limiting factor to juvenile Atlantic salmon abundance in small streams (see Turgeon and Rodriguez, 2005 for further details).
Antipredator responses and tactics in complex landscapes
Queen parrotfish fleeing from a "predator"
Flight initiation distance (FID) - the distance at which an organism begins to flee an approaching threat - is an important component of antipredator behavior. We used parrotfish species to test the effect of a diver on FID, escape speed - represented by the swimming gait; i.e. using the whole body propulsion or just the pectoral fins when fleeing, in relation to swimming capacity and body size. More particularly, we explore if antipredator traits are showing examples of compensation or co-specialization (see Miller et al. 2011). We also tested how escape responses change threat from humans (ex. protection status such as the Barbados Marine Reserve vs. reef experiencing spearfishing see Gotanda et al. 2009).
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