Scientists at Sea (Episode 1): Do crabs have ears? with Emily Carter

 

 

Show notes

 

Emily Carter – @E_E_Carter

How does noise pollution impact one of our coastal favourites? Ethan and Molly talk to Masters by Research student Emily Carter about her current work which investigates how the presence of ship noise affects the rate of colour change in shore crabs.

 

Other behaviours that don’t rely on noise at all can be quite drastically affected by noise pollution

Useful links from this episode:

Fiddler crab

Selfish herd hypothesis

Shore crabs

Crabs hearing noise

Gylly beach

Penryn Campus

Steve Simpson, Matthew Wale, Andrew Radford

Martin Steven’s Group/Sensory Ecology

 

 

 

 

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

 

 

 

 

 

 

 

My #ExeterMarine MSc: Skates on thin ice: a phylogenetic study of vulnerable elasmobranchs

Author – Maisie Jeffreys, MSc Student – Molecular Ecology and Evolution group

Elasmobranchs (sharks, skates and rays) are more vulnerable to extinction than any other vertebrate group, meaning their protection is more important than ever. However, confusion remains surrounding the taxonomy of many species- making conservation difficult. Hence, more research needs to be done to answer taxonomic questions that still surround these endangered species.  

Elasmobranchs are some of the most fascinating creatures of the underwater world. Currently, there are at least 1,118  extant species of sharks, skates, and rays found throughout all corners of the globe: from depths of up to 4,000m in the deep sea and the icy waters of the Arctic, to shallower habitats in estuaries and freshwater lakes. Indeed, this group of cartilaginous fish can be found in just about every aquatic ecosystem on the planet, where they play vital roles in maintaining ecosystem balance.

Unfortunately, elasmobranchs are a group at high risk of extinction; due to habitat destruction, overfishing, and being caught as bycatch, an estimated 25% of species are thought to be threatened worldwide. The impact of elasmobranch decline is poorly understood, but given their important roles in aquatic ecosystems, the consequences are likely to be far-reaching.

Of all the elasmobranchs, the batoids (skates and rays) are the most vulnerable, with around 20% now threatened with extinction. Despite this, effective conservation of batoid fish has been hindered by a lack of accurate scientific data; many species are now listed as ‘data deficient’ on the IUCN red list, making establishing accurate conservation methods difficult.

This lack of data can be partially attributed to the large degree of morphological and ecological similarities among living orders of skates and rays. These similarities cause high amounts of cryptic speciation (animals that look alike but are genetically distinct), which results in taxonomic confusion and unstable nomenclature.

A classic example of cryptic speciation can be found in the Manta rays. Currently, there are two species of Manta ray; the larger species, Manta birostris, can grow up to 7 m in width, while the smaller, Manta alfredi, reaches 5.5 m. However, these were thought to represent just one species until 2009, due to their morphological similarities. This discovery has been vital in the conservation of mantas, particularly as it has allowed the clarification of the two species’ ranges. Since M. birostris is thought to migrate across open oceans, while M. alfredi tends to be resident and coastal, conservation efforts have now been targeted accordingly.

My Masters by Research focusses on resolving taxonomic questions that still surround several other species of endangered rays and skates, including the ‘common skate’ complex (Dipturus cf. flossada and Dipturus cf. intermedia), the Norwegian skate (Dipturus nidarosiensis), the longnose skate (Dipturus oxyrinchus), the thornback ray (Raja clavata) and the Madeiran skate (Raja maderensis). In order to answer these questions, I will be using restriction-site associated DNA sequencing (nextRAD) and mitochondrial DNA (mtDNA) sequencing to build phylogenetic trees for analysis. This work could potentially lead to the discovery of new species of endangered skate and has important conservation implications for batoid fish.

This project, supervised by Dr Andrew Griffiths and Dr Jamie Stevens, forms just one part of a host of exciting work being done by the Molecular Ecology and Evolution group (MEEG) here at Exeter University. Several other marine projects are currently underway, including research into the population genetic variation of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar), and genetic connectivity in tropical corals and temperate invertebrate systems.

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

 

My #ExeterMarine PhD: Social learning in whales and dolphins: implications for their conservation

Author – Philippa Brakes  (@PBrakes)

Whales perform some of the longest migrations on earth. Many live in close family groups, some sing, feed cooperatively, transmit innovations, share the care of their offspring and are even vital ecosystems engineers. They are the stuff of legend and the cornerstone of many marine eco-tourism businesses around the world. Yet despite the size of these charismatic megafauna, both in life and in our imaginations, they remain somehow enigmatic: the details of their lives are challenging for us to grasp. Nevertheless, through long-term studies, we are starting to unravel some of the mysteries and these scientific insights also necessitate a re-evaluation of how best to conserve these giants of the deep.

Behaviour matters. One key issue for the conservation of whales – and likely many other taxa – is social learning. There is growing evidence that many species of whales learn some important behaviours from their elders and sometimes their peers. Evidence for social learning in whales is found in all the main behavioural domains; from communication to foraging, migration to play. This is significant for conservation efforts. Understanding that behaviours from foraging strategies to migration routes may be socially transmitted, requires us to reflect on the types of resources whales need to survive and thrive in ever changing environments.

 

The emerging evidence in this field is also now beginning to influence conservation policy. The UN Convention on Migratory Species (CMS)  has been spearheading important work in this area. At a Conference of the Parties in the Philippines late last year, CMS committed to further examine the importance of social learning for the conservation of a range of migratory species. CMS also agreed a concerted action for the acoustic clans of eastern tropical Pacific sperm whales, which requires cooperation among the range states to gather more information about the social behaviours of these whales.

 

The better we understand social networks, the types of relationships individuals have, how they innovate and share new information and the roles that specific individuals may play within their social groups, the better equipped we will be for bespoke conservation solutions for animals that learn socially. A key area of importance to conservation will be determining how foraging strategies are socially transmitted. If information about a new technique for foraging on a specific resource is transmitted within a social group, these individuals may become specialist feeders on a particular prey type. Potentially, this has both conservation and evolutionary advantage, if this behaviour results in more efficient prey gathering or provides access to more abundant or better quality prey. However, such specialisation is not without risk. A significant decline in a certain prey type may present a challenge to the survival of some specialist feeders, unless of course they readily swap to other types of prey.

This ability to swap behaviour may be key. For example, bottlenose dolphins have the capacity to socially transmit new foraging strategies. But this species also exhibits sufficient behavioural plasticity to diversify to other prey types when their environment changes and certain prey become scarce. In contrast, killer whales, who are considered more conservative in their behaviour, generally adhere rigidly to their prey specialisations throughout their lifetime. There may be a tension between conservatism and plasticity, both within individual behaviour and across species, which highlights the complexity of conserving animals that learn socially.

 

But social learning is not the whole story; social structure, social role and even distribution of consistent individual difference (or personality) may also have an influence on the trajectory of populations. To examine this further WDC (@WHALES_org) and #ExeterMarine (@ExeterMarine) are investigating a feeding innovation in humpback whales off Cape Cod in the U.S.A., with the kind help of amazing WDC North America interns. Here, as well as bubble net and lunge feeding, a group of humpback whales have learnt a unique feeding strategy called kick or lobtail feeding. These whales lift the tail fluke (or entire caudal peduncle) out of the water in order to strike the water hard with the tail fluke (at least once) to stun the sand lance. This is typically followed by the whales then corralling the stunned fish by blowing bubbles underwater and surfacing with a mouthful of seawater and fish, which is then strained through the baleen.

This foraging strategy is unique to the Gulf of Maine population of humpback whales.  Previous research has determined this behaviour has been socially transmitted between whales in this population for nearly three decades. WDC (@WHALES_org) and ExeterMarine (@ExeterMarine) are now exploring whether factors such as age or social position matter when learning these new foraging skills. Is success rate related to whom you learn from, or are some individuals more predisposed to try out new innovations? Do some whales perfect their technique more rapidly than others, does skill level increase over time? Or, are particular individual differences in feeding style consistent over a lifetime? Do some whales never quite get the hang of the optimal kick feeding style and does that influence their overall calorific intake, their reproductive success, or even their longevity?

Our research so far indicates that individual whales exhibit their own specific styles of kick feeding, the question is how and if these styles change over time. Another interesting discovery is that some whales in this group seem to be goal hangers! There may be a producer-scrounger system in operation among these whales, although how dynamic this situation is remains to be seen. Non-kicking ‘scroungers’ may be benefiting from feeding on the fish stunned by the kicking whales. This begs several questions. Does it pay sometimes to be a kicker (producer) and sometimes a scrounger? Or is this part of the process of learning this unique foraging strategy? Does scrounging behaviour vary with group size? Are there ecological constraints? Only by gathering data on how these individual whales feed will we gain a better understanding of how these systems work and what role consistent individual difference may play in the spread of social learning of particular foraging strategies.

We can look to other taxa for clues. For example, chimpanzees exhibit gender differences in learning, particularly in relation to attention to maternal techniques, which has been used to predict competence in learned behaviour at a later date. Understanding whether similar differences between males and females exist in humpback whales will enable a richer understanding of social transmission in these species.

One thing is certain: whale science has advanced considerably since the save the whale movement of the 70s and 80s. Contemporary efforts to conserve whales from human-induced rapid environmental change requires more sophisticated and strategic approaches to protecting populations, which in some cases includes defining and managing social units. Saving whales today requires us to rethink some traditional approaches for delineating populations and shine a light on some of the detail of their individual lives. Just as ecological and conservation thinking has evolved from the elementary description of basic food chains, towards grappling with the complexity of food webs, future conservation efforts will need to incorporate the many facets of the social, as well as ecological, aspects of the life histories of these leviathans.

 

#ExeterMarine is a interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

Exeter MSc Students Sharing Marine Science Widely

Prof Brendan Godley  teaches a MSc module on Marine Biodiversity and Conservation at the Centre for Ecology and Conservation on the University’s Penryn Campus. The students learn about a wide diversity of topics and undertake independent study on two major topics within their specific interests. These are assessed by a dissertation and an oral presentation to their peers, respectively. This year, the tutor challenged his students to go a stage further and produce an infographic to communicate the message of their oral presentation to a wide audience that could then be shared on Twitter or other social media platforms. Brendan wrote;

Communicating science, especially conservation science, to a wide audience is a key skill we all need to work on. This was my initial reasoning for setting the task. I think. however, that the exercise really challenged the students to distil and clarify their key take-home messages in advance of giving their talks. They achieved both of these aims with some aplomb and were widely complimented on their work.”

 

The module sees a range of invited marine conservation practitioners sharing their sectoral experience with the students. Katrina Ryan of Mindfully Wired a consultancy which specialises in science communication was one of the invited experts this year and gave the students feedback on their infographics as part of her session. Katrina added;

“It’s wonderful to see vital communication skills being fostered as part of these students’ wider conservation science learning. Condensing such complex subject matters into compelling graphics is a real challenge, but the students did a superb job and, as a result, many had significant impact on social media”

Tweet from Hetty Upton

Click her to see a storify of the tweets, starting with the single most impactful by Hetty Upton.

 

#ExeterMarine is a interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

 

My #ExeterMarine PhD: Marine Turtles of Brazil

Author – Lili Colman (PhD Student) – Centre for Ecology and Conservation, Penryn Campus

From the moment I arrived at the University of Exeter to undertake my MSc in Conservation and Biodiversity, I quickly fell in love with the University, the Campus and Cornwall. Discovering all the cutting-edge research being carried out across the University of Exeter has been a definite highlight for me. The opportunity to participate in the Africa field course was one of the most amazing experiences of my life and one I will always cherish, having helped me build a practical understanding of large-scale conservation issues. My MSc research project centred on analysing 30 years of mark-and-recapture data from juvenile green turtles on an isolated tropical archipelago in Brazil, under the supervision of Prof Brendan GodleyThis published work contributes important insights regarding demographic parameters and population trends for this species.

Lili_Kenya
Meeting the Maasai in Kenya

 

Upon my return to Brazil, and whilst working as an environmental consultant there, I applied for a PhD at Exeter to work with TAMAR (the Brazilian Sea Turtle Conservation Programme). This on-going conservation project illustrates a powerful example of how marine turtles and coastal communities can co-exist in an ever-changing world. Despite a history of over-exploitation, the five different species of marine turtles that nest in Brazil are now fully protected by law. And as a result, recent years have shown very promising signs of population recovery. Perhaps most notably, a major part of this success can be attributed to the active involvement of the surrounding coastal communities in the conservation work. What once started in the direct employment of former egg poachers, now involves a wide range of activities to encourage environmental awareness in the area. This includes environmental campaigns, alongside the support of alternative, sustainable economic opportunities for the communities living near the nesting beaches.

Tamar

Local kids talking turtle in Bahia, Brazil (Banco de imagens Projeto TAMAR)

My PhD research focuses on the highly migratory leatherback sea turtle (Dermochelys coriacea). This species has its major nesting site deep in the southwestern Atlantic ocean in eastern Brazil, on the northern coast of Espirito Santo. Projeto TAMAR has been monitoring the area since 1983 and there are promising signs of population recovery for the species. However, with a small population size and restricted geographical distribution, alongside the emergence of new threats – coastal development, fisheries bycatch, climate change, marine and light pollution – the population continues to be of conservation concern.

(Henrique Filgueiras)
Lili records leatherback sea turtle nesting (Henrique Filgueiras)

As part of the Marine Turtle Research Group (MTRG) at the University of Exeter, we are using a variety of techniques to investigate this population’s ecology, trends and the main impacts they are facing. This research is being done in collaboration with TAMAR in Brazil and Ciência Sem Fronteiras , a scholarship programme from the Brazilian Government. The knowledge obtained in this study will be used to design better and more effective conservation strategies for this species. I was delighted that my PhD project was chosen to feature in one of the films to celebrate TAMAR’s 35th anniversary:

#ExeterMarine is a interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!