Anna is collecting genetic information from white shark fin clips to assess this species’ population size in South Africa. Using close-kin mark-recapture analysis instead of traditional methods, she hopes to provide an accurate account of South Africa’s white shark population size. She also aims to develop a monitoring protocol that can use genetic samples collected during shark net and drumline patrols by the KwaZulu-Natal Sharks Board. This information is needed in South Africa, where the conservation of a protected species is balanced against concerns about bather safety, and where sharks are caught in bather protection gear.
My interest in the ocean began when I was growing up in Alaska, where I was lucky enough to spend lots of time on the water and among the region’s coastal communities. I always knew that I wanted to study marine ecosystems, but my scientific journey has been anything but straightforward.
My first real foray into research was during an internship in the Caribbean, studying the ecology of coral reefs. Intrigued by the tropics, I moved to Guam to complete my Master’s degree and launched diving expeditions to Micronesia, Japan and the Mariana Islands to collect samples of marine plants...
To estimate the size of South Africa’s great white shark population by means of the innovative method of close-kin mark-recapture analysis, which uses genetic relatedness of the individuals sampled.
South Africa’s great white sharks Carcharodon carcharias present a unique case study of the complicated politics surrounding human–wildlife interactions. Measures to protect swimmers, such as the shark nets maintained by the KwaZulu-Natal Sharks Board, are a fine trade-off between the public desire for accident prevention and the conservation of viable shark populations. Accurate population estimates are required to keep this balance, and this project uses genetic information from routinely collected fin clips to provide that information.
South Africa’s great white sharks have been protected from targeted fishing since 1991 and the need to monitor their population has been highlighted by the South African government, but recent robust population estimates are unavailable and new ones are difficult to obtain. To date, research on the population of great white sharks in South Africa has relied on traditional mark-recapture methods, which depend on tagged animals being ‘recaptured’ to produce population estimates. The first study of this kind used dart tags to mark adult sharks, whereas others have used individual dorsal fin markings as ‘tags’ to estimate population size. Each of these methods requires extensive field work, which makes them expensive to continue.
In contrast to traditional mark-recapture studies, a close-kin mark-recapture analysis relies on genetic markers to identify parent–offspring pairs that constitute a ‘recapture’ of the parental individual. Because the ‘tag’ is contained within the individual’s genetic data, each animal needs to be encountered only once and therefore does not have to be recaptured or seen again. The KwaZulu-Natal Sharks Board’s programme of maintaining devices to protect swimmers requires frequent monitoring of its nets and drumlines, which means that there are regular opportunities for additional samples to be collected. These future samples can be sequenced, added to the existing genetic data already collected for this study and used for population monitoring.
Faqih is filling the gaps in the scant knowledge of giant guitarfish in Java’s Karimunjawa National Park marine protected area (MPA). Karimunjawa is located near Northern Java’s main fishing grounds, but evidence of giant guitarfish caught in some of the use-zones of the MPA hints that the park may be a sanctuary for the species. Managing giant guitarfish in Karimunjawa requires species-specific information.
Faqih’s project is a socio-ecological one to help inform management and draws on new information about relative abundance and distribution, historical occurrence and fishing pressures to paint a contemporary picture of the species in the park.
Cindy wants to know if bonnethead sharks in the Eastern Pacific constitute a third, cryptic species. The Bonnethead complex need clarification in all its distribution range, and Panama is a key country to solve this question since we have the Caribbean sea and the Pacific Ocean. By collecting fin clip samples to compare species at the genetic level and collecting specimens to compare how they look (morphology), Cindy hopes to resolve the taxonomy of Sphyrna tiburo vespertina – that is, whether it’s a cryptic third species for bonnetheads in the region. Her information can help update the IUCN Red List for bonnetheads and improve fisheries policies in Latin America where bonnethead sharks are commonly caught.
Meghan wants to know all about sevengills in San Francisco Bay: what they’re eating at different ages and life stages, where they’re spending their time, and whether they are stressed by handling in the recreational catch-and-release fishery. Answering these questions will help her inform their ability to survive and thrive after being handled, whether there are any threats to their particular dietary needs at vulnerable stages in their life, and what the ecosystem that they most need looks like. Ultimately, this project will help inform fisheries management and hopefully better protect sevengill sharks on the Eastern Pacific coastline.