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Information on the foraging behaviour of sea snakes has the potential to clarify adaptive pathways involved in the evolutionary invasion of marine habitats by terrestrial vertebrates. However, logistical obstacles have precluded studies in this field. To obtain preliminary data of diving behaviour, we surgically implanted temperature-depth loggers into two sympatric, amphibious, benthic foraging sea krait species from New Caledonia. Based on logger recovery from three snakes (1 L aticauda laticaudata and 2 L . saintgironsi), we obtained data on a total of 1850 dives carried out over eight foraging trips and 39.6 days at sea. Almost 99% of dives were <30 m deep. Average dive depth was 10.7 ± 7.0 m, but snakes dived as deep as 82.6 m. Maximum dive duration was ≥123.7 min. At sea, snakes dived continuously, with over 90% of surface recovery periods lasting less than 3 min in L. saintgironsi ( n = 1). Periods at the surface (between successive dives) were longer at night than by day, plausibly reflecting more intense hunting activity by the snake. Locomotor speed, as measured by the rate of vertical descent or ascent during diving, was low (0.15 m s−1). In combination with other data on these species, we estimate that metabolic expenditure was about 10 times greater while the snakes were at sea than on land; and their overall field metabolic rate (70-145 kJ kg−1 day−1) was an order of magnitude less than has been reported for diving endotherms. Despite low sample sizes, our study shows that implanted data loggers can provide novel insights into sea snake biology. Our data emphasize the behavioural and ecological consequences of ectothermy for secondary marine vertebrates. In particular, they illustrate how ectothermy allows species to thrive on rates of energy intake vastly lower than are required for their endothermic competitors. [ABSTRACT FROM AUTHOR]

ABSTRACT The Illinois River Biological Station monitors fish communities in the Illinois River using two different electrofishing programmes, one using three-phase alternating current [AC; The Long Term Illinois Fish Population Monitoring Program or long-term electrofishing (LTEF)] and the other pulsed direct current [DC; The Long Term Resource Monitoring Program (LTRMP)]. In 2001, we replicated three-phase AC sampling sites with pulsed-DC electrofishing gear to test for differences between the two collection methods and programmes. Electrofishing runs at each site were standardized by length and time, with 48 samples collected for each gear. Our objective was to test for differences in fish catch rates using total catch, species richness, fish size ranges, and sample composition and structure. Total catch was significantly greater for LTRMP electrofishing (4368 total fish, mean = 91.0 fish per sample) compared with LTEF electrofishing (1423 total fish, mean = 29.6 fish per sample). Species richness also was significantly greater for LTRMP electrofishing (50 total species, mean = 12.9 species per site) compared with LTEF electrofishing (38 total species, mean = 7.9 species per site). Size ranges of fishes, composed of 100-mm-length groups, showed higher total catches for the LTRMP within all length groups. Although our analyses suggest that collections from the LTRMP were significantly greater in most instances, a consistent pattern of species composition between the two programmes was not evident. Our results suggest that caution must be taken when attempting to compare fish community composition and structure information between these programmes. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]