Brendan Talwar

A crowdfunded ecology project byBrendan Talwar


New publications: Micropredators and Blood

Lab Note #24
Feb 27, 2017

Hi everyone!

It has been almost three years since we started this project. It is truly remarkable how much has happened since then and how much we've been able to contribute to the body of knowledge on deep-sea bycatch species- thanks in large part to the initial funds provided by all of you! 

As time has passed, we've slowly published our results one piece at a time. Last year, we shared our article on the post-release mortality of giant isopods in ICES Journal of Marine Science. Later in 2016, while working collaboratively with Ollie Shipley at the Cape Eleuthera Institute, we released a short publication on micro-predatory isopods (meaning they actively feed on numerous individuals throughout their life, as opposed to parasites which feed on just one host) that we collected from the sharks hauled up from depth, which I'm happy to share:

Full HTML Article (and in PDF format below). 

One of the isopods that we found on our sharks.

Also, while conducting our primary study on deep-sea sharks (currently in review), we drew blood from all captured individuals in order to predict mortality using physiological markers like blood lactate and pH. In order to measure blood pH, we used a point-of-care blood analyzer called an iStat, which has been used for quite some time in this capacity. Unfortunately, it isn't suited for the rough conditions that we put it through, and we were often hoping for an alternative to come along to collect these data at reduced cost with less headaches. We decided to try out a new instrument that created less waste, was field-worthy, and substantially cheaper than the iStat and then compared our results between the two instruments. What we found was that the Hanna pH meter, a new instrument technically designed for use on meat & dairy products, could measure the blood pH of both the Cuban dogfish and lemon shark and report values similar to those obtained from the i-Stat. Given their similarity, we created equations that relate the Hanna pH meter values to those from the i-Stat, which has been validated for use in some sharks, as well as those from more standard laboratory quality analyzers. 

Hopefully, as a result of our work, scientists now can use this device to measure shark blood pH at reduced cost and with greater ease, while also reporting comparable results to those from previous studies. Feel free to read the whole publication published in Conservation Physiology:

Full HTML Article (and in PDF format below).

Blood analyzers from left to right- glucose meter, lactate meter, Hanna pH meter, and i-Stat

And, on a side note, I am particularly proud of this one. I've had the opportunity to work with amazing people along this ride and some of my all time favorites are authors on this paper. A big thank you goes out to them for being wonderful collaborators. 



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