Torben Wolff, legendary deep-sea scientist and last surviving member of the Galathea II expedition, which plumbed the Philippine Trench and recovered biological material from more than 10,000 meters for the first time in history, died in his sleep on May 2, 2017. He was 97.
Torben will be remembered for his monumental contributions to deep-sea oceanography, his commitment to international collaboration in the deep sea, and three generations of mentorship, as well as his tradition of closing deep-sea meetings with a Haka that he learned from Maori during his travels in New Zealand.
Farewell Torben. We’ll see you some day in Fiddler’s Green.
An Australian research expedition has successfully deployed three satellite telemetry tags on sawsharks for the first time! These rarely-seen sharks have a toothy rostrum similar to a sawfish, but are true sharks while sawfish are rays. Sawshark rostrums also have sensory barbels, unlike the rostrums of sawfish. “This is actually a good example of convergent evolution where two distantly related species have adaptations that have converged to be very similar in looks and (purportedly) function,”said professor Jane Williamson, the head of the Marine Ecology Group at Macquarie University and the leader of this expedition. “Sawsharks probably use their rostrum in a similar manner to sawfish: as a tool for sensing and capturing prey, and possibly for self-defense.”
Shark wildlife tourism* is a growing marine industry with big implications for shark conservation. While there are many competing definitions, generally shark wildlife tourism refers to SCUBA dive operators who offer trips that guarantee that you’ll see sharks, often through the use of bait or chum to attract sharks to the divers. This has become a contentious issue in marine science and conservation circles. That’s why last week’s news that WWF, Project AWARE, and the Manta Trust released the first-ever guide to responsible shark and ray tourism best practices is so welcome. This thorough and well-researched guide guide is designed for dive operators who want to minimize their potential harm to sharks and rays while maximizing the potential conservation benefits of shark wildlife tourism.
A lesser electric ray. Photo credit: Brandi Noble, NOAA Fisheries Service
The lesser electric ray, a small sand-dwelling ray that lives from North Carolina to Brazil, has been considered one of the most endangered marine fish on Earth. A 2005 paper reported that 98% of these rays had been wiped out, a decline attributed to shrimp trawling bycatch. This paper resulted in these animals getting classified as IUCN Red List “Critically Endangered,” the highest risk category for any species that is still found in the wild.
A new paper published today in the journal Endangered Species Research shows that these rays are in much better shape than previously believed. “There is no evidence of a decline in the relative abundance of lesser electric rays,” said Dr. John Carlson, a NOAA Fisheries Service Research Biologist and lead author of the new paper.
Bonnethead sharks, one of the smallest members of the hammerhead shark family Sphyrnidae, have a special place in my heart. For many years, the avatar I used for science communication efforts, including posts on this blog, was a picture of me with a bonnethead.
Remember this avatar? That’s a bonnethead (on the left).
These sharks, which can grow up to about 5 feet long, are found throughout North, Central, and South America. However, new research by Fields and friends suggests that they may actually be a species complex, not a true species. “A species complex is a group of distinct species that are incorrectly classified as one species because they look very similar to one another,” explained Dr. Demian Chapman, an Associate Professor of Biology at Florida International University and a co-author on this new study. “A great example is the white spotted eagle ray (Aetobatus narinari) that was once thought to be one, globally distributed species, but now has been shown to be a group of very similar-looking species, each of which lives in a particular region.”
Plastics, more importantly microplastics, clog our oceans. This phenomena in the ocean has been likened to smog around cities. These plastic particles are dangerous because they can absorb toxins, subsequently be consumed by zooplankton and invertebrates, and bioaccumluate up the food web to fish that are consumed by humans. A study in Nature found that 25 percent of seafood sold contains microplastics! There has been a recent awareness of the unseen harm that exists when plastic pollution in the ocean degrades into microplastics. A report in Environmental Research Letters estimated that “accumulated number of micro plastic particles… ranges from 15 to 51 trillion particles, weighing between 93 and 236 thousand metric tons.” That is cray cray. Despite a better awareness of the impact of microplastics on marine ecology, we still have a poor spatial understanding of microplastics in the ocean. The presence and density of microplastics is determined by trawling the ocean (i.e., researchers go out with a net and physically count the pieces of plastic they pick up). As you can imagine, this is not very effective.
Conceptualization of plastic degrading in the ocean. (Photo credit: Archipelagos Institute)
The fam attending my dissertation defense
After a little more than 5 years of hard work, I’ve officially completed my Ph.D.! You can read my dissertation (“An Integrative and Interdisciplinary Approach to Shark Conservation: Policy Solutions, Ecosystem Role, and Stakeholder Attitudes”) online here in its entirety.
In case there are some among you who don’t really want to read a 281 page dissertation but are curious about what I found, I’ve prepared this blog post to summarize my key conclusions. (Note: this does not include every conclusion. Some are aggregated together, and some more technical conclusions are omitted for this summary).