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bonefish

Carleton University Students Studying Thermal Tolerances in the Checkered Puffer Fish and Bonefish at CEI

[slideshow] Two students from Carleton University in Ottawa, Felicia St-Louis and Petra Szekeres, will be on The Island School campus until June 19th collecting data for their research on the thermal biology of the checkered puffer fish (Sphoeroides estudineus) and bonefish (Albula vulpes). Over her short visit this past February, Felicia was able to validate intra-muscular cortisol injections as a method of increasing blood cortisol (i.e. a stress hormone) to ecologically relevant levels in the checkered puffer for her MSc project. She is examining the effects of short-term cortisol elevation on the thermal biology of the puffers in the lab as well as in the field. By building a thermal profile of Page creek and releasing puffers tagged with thermal logging iButtons within the creek for a one month period, she will be able to compare habitat preferences between control and cortisol-dosed puffers. Determining the effects of additional environmental challenges such as temperature, on the physiology and behaviour of animals is relevant to understanding the thresholds for survival and predicting the associated ecological consequences. Felicia expects to shed some light on the physiological, behavioural and ecological effects of environmental change on coastal marine wildlife. Petra’s undergraduate research stems from the Florida cold snap of 2010 that resulted in over a million dead game fish including tarpon, snook and bonefish. The sublethal physiological and behavioural effects of the cold shock on bonefish were unknown. She is therefore, evaluating the consequences of a short term cold shock on bonefish. The physiological aspect of her study consists of taking a small blood sample, which will be analyzed for cortisol, lactate and glucose concentrations, pH and hematocrit. The behavioural aspect of her study consists of simulating response to a predation event as characterized by the distance they swim and the time it takes to exhaust the fish. This project hopes to achieve a framework for the sublethal consequences of cold shock in bonefish with regard to their stress levels and predator avoidance behaviour.

Carleton University Research at CEI

Researchers from Carleton University (Cooke Lab) was at CEI last week studying flats ecology. The team is determining whether radio tags can be used to track the movements of checkered puffers in shallow mangrove habitats. Radio tags normally are used only in freshwater because signals are attenuated by sea water. However, the researchers have modified the tags such that the antenna points vertically and breaks the water surface as puffers swim about in tidal creeks. In addition, the researchers placed tri-axial accelerometer loggers on bonefish in McKinney Creek at CEI. The loggers record information on swimming (e.g., tail beats) and feeding (e.g., tilting as they dip their heads to feed) activity. This is the first time that such loggers have been used on bonefish and will provide information that will serve as the basis for a bonefish bioenergetics model. The same loggers were also placed on some fish in Kemps Creek to evaluate the effects of different handling techniques on post-release behaviour. The Carleton team includes Jake Brownscombe, Felicia St. Louis, Charles Hatry, Jason Thiem, and Dr. Steven Cooke. [slideshow]

Update from CEI's Flats Ecology Research

[slideshow]

So everyone has heard of climate change/global warming- increased anthropogenic CO2 in the Earth’s atmosphere shifts annual global climate, which then leads to other catastrophic events within the Earth’s ecosphere. An increase in oceanic temperature and acidity is among the most pressing and readily apparent effects of climate change. Past research has shown fish of tropical reefs to be particularly sensitive to changes in ocean temperature and pH. In the flats department, we aim to determine whether common teleost occupants of tropical mangroves exhibit a similar sensitivity to such changes. Using bonefish (Albula spp.), checkered puffers (Sphoeroides tetudineus), juvenile yellowfin mojarra (Gerres cinereus), and juvenile yellowtail snapper (Ocyurus chrysurus), we aim to determine the Critical maximum and minimum temperature and pH at which each species looses equilibrium (“goes belly up”). With the help of visiting students from the Maine School of Science and Mathmatics, we have already determined the critical maximum temperature for puffers, mojarra, and snapper by observing behavior of test subjects while gradually increasing the ambient temperature. With our recently engineered water-cooling system, we plan on determining critical minimum temperature this week! Once completed this study will help us to predict the phenotypic plasticity of these mangrove species in response to rising oceanic temperatures and acidity.