Searching for Lost Sharks: Extinct or Alive?

The public’s perception of sharks conjures up images of large, fearsome, toothy predators, with its large dorsal fin cutting its way through the waters’ surface. In reality sharks and rays are highly diverse and can be informative of the health of the marine environment. To that end, a 2014 study found that nearly one-quarter of all chondrichthyan species maybe threatened with extinction. A follow up study found that number had increased to about one-third of all chondrichthyans may now be faced with extinction, with at least one species now considered extinct and two more species considered possibly extinct. The current number of observed threatened species is more than twice that of the first global assessment.

Project leader Dave Ebert and Julia Constance, Ph.D. candidate at Charles Darwin University, discussing the Java Stingaree (Urolophus javanica) the first marine fish extinction attributed to human activity. Photograph © David Ebert

The scale and drivers of this biodiversity loss were revealed by the International Union for Conservation of Nature Red List Assessment process. Over-fishing, habitat loss and degradation are the primary drivers with pollution and climate change also being contributing factors. Despite the increasing extinction risk, the number of sharks, rays, and ghost sharks (collectively referred to as ‘sharks’) has increased exponentially over the past 15 years with over 20% of all known species having been described. Although the number of species has been increasing, many known species have simply vanished without notice. Some groups (sawfishes, angelsharks, devil rays) have gained attention through working groups and improved management policies, but most species, such as guitarfishes, have remained largely anonymous to the public.

Guitarfishes, like those pictured here at a fish market in northern Peru, are one of the most critically endangered vertebrate groups. Photograph © David Ebert

Most of these threatened species occur in subtropical and tropical coastal waters, in regions considered biodiversity ‘hotspots’ and where food security is of primary concern. Compounding the problem is a lack of adequate species-specific identification knowledge and guide materials. Awareness of these issues are largely absent from most western organisations where the majority of sharks have largely been “lost” in a hyper-driven media age whereby a few large charismatic sharks overshadow the majority of species. While a few charismatic species receive much media, conservation, and scientific attention, the fate of over 1,200 species of “Lost Sharks” remains largely unknown.

The Clown Wedgefish (Rhynchobatus cooki) was thought to be potentially extinct until it was recently re-discovered at fish markets in SE Asia and in the Riau Islands, Indonesia. The status of the Clown Wedgefish is the focus of a SOSF Keystone Project “Tearing up the obituary for a lost wedgefish” with Project Leader Peter Kyne. Photograph © David Ebert

Given this urgency, San Jose State University’s Pacific Shark Research Center’s Lost Sharks project has partnered with an international team of regional and local experts in Africa, Asia, Europe, Indonesia, and South America aiming to search for shark species not seen in decades. Each location will highlight a suite of sharks with an emphasis on critically endangered and possibly extinct species being highlighted. To raise public awareness of their plight we will document our search for these lost sharks through scientific publications, outreach, media distribution through various outlets, and speaking engagements. Information gathered through this project will be critical to our local partners in developing future conservation and management policy.

Raising public awareness through presentations to various organisations such as dive groups is crucial to bring attention to little known sharks and rays. Photograph © David Ebert

Identification field training workshops to CITES port inspectors, like this group in Indonesia, are important for improving species-specific identification of sharks and rays. Photograph © David Ebert

Meeting with local fishermen in coastal towns and villages to learn local fishers knowledge and raise awareness of species that have not been seen in decades is critically important to understanding current and historical. The present project is also developing a documentary series to highlight the journey. Photograph © David Ebert