John is developing a set of targeted ‘capture panels’ that focus DNA sequencing efforts on specific regions of the cownose ray genome that can be used to identify related individuals. These panels will facilitate construction of a close-kin mark-recapture model to estimate abundance of cownose rays along the US East Coast.
I don’t know why or where it came from, but I have felt drawn to the ocean and captivated by elasmobranchs (sharks and rays) for as long as I can remember. Over the years, as I studied elasmobranch biology and sought opportunities to interact with the animals, my casual interest transformed into a passion; the more I’ve learnt, the more I’ve come to realise how exceptional sharks and rays are. Their uniqueness arises from their evolutionary history. Sharks and rays (and chimaeras) took their own evolutionary path relative to other vertebrates about 450 million years ago. This does not mean...
Concurrent with development of a species management plan in Maryland, this project will assess population connectivity of cownose rays in the Western Atlantic Ocean and use the data to develop targeted DNA capture panels that can be used for kinship identification. The methods and results from this project will aid future efforts to estimate population abundance using close-kin mark-recapture (CKMR).
This project is unique because it combines cutting-edge genomic techniques with new advances in statistical modeling to address a critical issue that has plagued effective elasmobranch conservation for decades. CKMR is likely to revolutionize elasmobranch conservation, but first it must be field-tested in a system with a well-understood life history, as these are essential covariates in CKMR models. Cownose rays fit this bill perfectly.
In addition, we are developing resources that will streamline future genomics and CKMR work in cownose rays and other closely-related species of conservation concern, such as eagle rays and mobula rays. In developing capture panels and testing their versatility, this project is expected to produce valuable a resource for the elasmobranch research community and also provide a road map for other researchers wishing to integrate these tools into their programs.
The threats facing elasmobranchs are numerous and complex, from targeted fishing for consumption, to non-target removal as bycatch and recreational fishing for sport, all of which contribute to the alarming decline of elasmobranch populations. As solutions are sought and ways to implement them explored, populations continue to be exploited at rates that are difficult to quantify because tracking abundance of these elusive animals has proven very difficult. This makes it challenging to manage elasmobranch populations in a sustainable way. However, recent breakthroughs in technology may offer a solution to this conundrum.
Close-kin mark-recapture (CKMR) is an emerging approach that fuses the burgeoning fields of genomics and population modeling by analyzing genomic data in a mark-recapture framework to give estimates of population abundance and survival. Importantly, CKMR can be applied in settings where samples are obtained lethally or non-lethally, making it useful for species that are culled as bycatch and also endangered species that are caught and released alive. Further, CKMR can estimate adult abundance using samples from juveniles alone, and could be a great tool for researchers studying elasmobranchs that are most easily caught as juveniles in nursery habitats.
Though CKMR has already been applied to two species of bony fish, CKMR models are heavily dependent on the biology of the species, and this method has not been validated in elasmobranchs, which vary substantially in their life history. The overarching goal of this project is to demonstrate the utility of CKMR for elasmobranchs by field-testing it in a species of growing conservation concern: cownose rays. Once the CKMR framework has been validated and best practices for the method established, CKMR has potential for immediate application to other threatened species for which robust tissue collections already exist, including smalltooth sawfish and spotted eagle rays.
Tanja is learning where the flapper skate moves along the last vestiges of its home range on the Scottish west coast and trying to understand how this affects its genetic diversity. To find out how its declining populations can survive, she is introducing the paternity test to the shark world and exploring whether mating partners, siblings or whole clans are commonly in the same area or if they can be found in different places.
Protecting threatened species means knowing enough about their biology to make informed decisions about how to manage their populations. To help fill the gaps in knowledge about a highly threatened shark-like ray, Brooke will be investigating the biology of two populations of the Critically Endangered bottlenose wedgefish: one from South-East Asia (Singapore, Indonesia and Malaysia) and the other from northern Australia.
Juan is on a mission: to get local people into the ocean around the Galápagos Islands and thereby spark a connection that will see them want to protect their environment. As the leader of the Charles Darwin Foundation’s Education Program, Juan runs experiential marine education activities that tie into the islands’ formal and informal education systems. His project funding will help expand his development programmes for learners, helping them to foster a real curiosity about and passion for the ocean.