Laser photogrammetry was found to be a promising new cost-effective technique for measuring free-swimming whale sharks Rhincodon typus. Photogrammetric measurements were more precise than visual size estimates by experienced researchers, with results from the two methods differing by 9· 8 ± 1· 1% (mean ±s.e.). A new metric of total length and the length between the fifth gill and first dorsal f...

1. Animal search patterns reflect sensory perception ranges combined with memory and knowledge of the surrounding environment. 2. Random walks are used when the locations of resources are unknown, whereas directed walks should be optimal when the location of favourable habitats is known. However, directed walks have been quantified for very few species. 3. We re-analysed tracking data from thre...

The weakly electric fish, Gnathonemus peters;;, explores its environment by generating pulsed elecbic fields and detecting small pertwbations in the fields resulting from nearby objects. Accordingly, the fISh detects and discriminates objects on the basis of a sequence of elecbic "images" whose temporal and spatial properties depend on the timing of the fish's electric organ discharge and its b...

OBJECTIVES AND SETTING Injuries from in-line skating have risen sharply in many cities around the world. To understand risk taking behavior and safety practices associated with urban in-line skating, 2210 outdoor skaters were observed in Boston, Massachusetts. METHODS Estimated age, gender, use of helmets, wrist guards, elbow and kneepads were recorded. Skaters were coded as beginner, average...

Sharks can use their electrosensory system to detect electric fields in their environment. Measurements of their electrosensitivity are often derived by calculating the voltage gradient from a model of the charge distribution for an ideal dipole. This study measures the charge distribution around a dipole in seawater and confirms the close correspondence with the model. From this, it is possibl...

Aquaponic fish to plant ratios, or more correctly, aquaponic feeding rate ratios, are an area of aquaponics that have been much debated. There seems to be many approaches to sizing the two main components of aquaponic systems (the fish component and the plant component), whether in a hobby-scale context or a commercial-scale context. I often say that ratios are the “Golden egg” of aquaponics as...

.................................................................................................................................................... 3 LIST OF ORIGINAL PUBLICATIONS....................................................................................................... 5

A long-standing question in community ecology is whether food webs are organized in compartments, where species within the same compartment interact frequently among themselves, but show fewer interactions with species from other compartments. Finding evidence for this community organization is important since compartmentalization may strongly affect food web robustness to perturbation. However...