Environmental constraints upon locomotion and predator–prey interactions in aquatic organisms: an introduction

Abstract

Environmental constraints in aquatic habitats have become topics of concern to both the scientific community and the public at large. In particular, coastal and freshwater habitats are subject to dramatic variability in various environmental factors, as a result of both natural and anthropogenic processes. The protection and sustainable management of all aquatic habitats requires greater understanding of how environmental constraints influence aquatic organisms. Locomotion and predator-prey interactions are intimately linked and fundamental to the survival of mobile aquatic organisms. This paper summarizes the main points from the review and research articles which comprise the theme issue 'Environmental constraints upon locomotion and predator-prey interactions in aquatic organisms'. The articles explore how natural and anthropogenic factors can constrain these two fundamental activities in a diverse range of organisms from phytoplankton to marine mammals. Some major environmental constraints derive from the intrinsic properties of the fluid and are mechanical in nature, such as viscosity and flow regime. Other constraints derive from direct effects of factors, such as temperature, oxygen content of the water or turbidity, upon the mechanisms underlying the performance of locomotion and predator-prey interactions. The effect of these factors on performance at the tissue and organ level is reflected in constraints upon performance of the whole organism. All these constraints can influence behaviour. Ultimately, they can have an impact on ecological performance. One issue that requires particular attention is how factors such as temperature and oxygen can exert different constraints on the physiology and behaviour of different taxa and the ecological implications of this. Given the multiplicity of constraints, the complexity of their interactions, and the variety of biological levels at which they can act, there is a clear need for integration between the fields of physiology, biomechanics, behaviour, ecology, biological modelling and evolution in both laboratory and field studies. For studies on animals in their natural environment, further technological advances are required to allow investigation of how the prevailing physico-chemical conditions influence basic physiological processes and behaviour.

Body morphometrics, swimming diversity and niche in demersal sharks: a comparative case study from the Mediterranean Sea

“…this may indicate speciesspecific amounts of phenotypic plasticity (Domenici et al, 2007;higham, 2007) in response to the effect of changing hydrological conditions and/or ecological demands (i.e. increasing drag per unit length experienced by larger fish, different aptitudes for swimming, pelagic shift in habitat of adult individuals, different depths inhabited and/or trophic level).…”

“…taking into consideration the suggestions by higham (2007) and Domenici et al (2007), interrelationships between body characteristics, swimming ability and occupied niche can also be expected for demersal sharks. the latter represents a group of elasmobranch species with disparate body shapes, distributed from coastal to deep water environments (compagno, 2002), and that interact with the bottom to different extents (hennemann, 2001).…”

“…however, aquatic organisms adapt to changes that may occur at different rates through phenotypic plasticity and natural selection (Domenici et al, 2007). recently, scientific debate has been focused on genetic differentiation and/or phenotypic plasticity in elasmobranchs.…”

“…as extensively reviewed and discussed by higham (2007) and Domenici et al (2007), locomotion, feeding and ecological constraints cause small but constant stresses to aquatic organisms and act as selection factors for adaptive morphological changes (Gould and eldredge, 1977;alberch et al, 1979), even in a relatively short amounts of time (Gould and eldredge, 1977). however, aquatic organisms adapt to changes that may occur at different rates through phenotypic plasticity and natural selection (Domenici et al, 2007).…”

Thermal acclimation of interactions: differential responses to temperature change alter predator–prey relationship

“…The outcomes of biotic interactions depend on the performance of individuals, so that interactions can be affected by environmental factors that modulate physiological performance. Predator -prey interactions depend on locomotion and its underlying physiological mechanisms [6], and in ectotherms it is likely that these interactions will be modified by the thermal environment. The thermal sensitivity of locomotor performance in ectotherms differs between species [7,8], and predators and their prey may respond differently to similar thermal changes [9,10].…”