So I asked leading shark ethologist and behaviourist, Professor Samuel 'doc' Gruber to elaborate. After pointing out how much pain women feel when they give birth, making the point that suffering has no effect on reproduction, he reminded me that sharks evolved their mating behaviours and the physical structures involved, separately from other animals.
The sightings, documented in a study by Amy Rose Coghlan and Naiti Morales, took place during a period of unusually warm sea surface temperatures, a condition that has been linked to the expansion of tiger shark habitats in other parts of the world.
The study, led by researcher Isabel Wagner, used a groundbreaking approach. They combined advanced genetic techniques (including target gene capture sequencing and whole-genome re-sequencing), to analyse the DNA of white sharks from across their global range. Eighty-nine individual sharks were examined through target gene capture sequencing, and seventeen sharks were studied through whole-genome re-sequencing.
During ten days of fieldwork in 2022 and 2023, researchers caught ten sharks from the broadnose sevengill and the endangered soupfin species.
The Salish Sea separates northwest Washington from British Columbia's Vancouver Island. The 6,500-square-mile body of water stretches into Washington as Puget Sound, and the sharks were caught close to Olympia near the sound's southernmost point.
A new study has shed light on the surprising ways that the great sharks contribute to their ecosystems. They help transport nutrients across marine ecosystems, which involve a variety of forms of marine lifeforms. As the climate warms and human activities continue to alter ocean conditions, their roles are shifting. Some species expand their ranges to cooler waters, affecting new areas and interactions.
In an alarming discovery, researchers have found traces of cocaine in sharks off the coast of Brazil. This revelation underscores the far-reaching effects of drug pollution on marine ecosystems and raises significant concerns about the health of these apex predators.
The study describes how the researchers launched a drone from the beach and flew it to the site of a disturbance spotted from shore. Two basking sharks (Cetorhinus maximus) were immediately seen in close proximity—one near the bottom and one near the surface. The latter was confirmed to be a mature male due to the presence of claspers, while the shark near the bottom appeared to be a female.
Sharks first appeared in the fossil record about the same time that plants covered the land, nearly half a billion years ago. Evolution has made them so perfect that they have retained their main characteristics over all of this abyss of time. But despite their formidable lineage, modern sharks face unprecedented threats and challenges that endanger their diverse roles within ecosystems.
Having photographed most of the sharks and rays that can be seen on scuba around the world, Andy Murch is doggedly pursuing the remaining few. Recently, his elasmobranch obsession took him to Papua New Guinea, where he hoped to find three endemic species of epaulette sharks.
Steven Minaglia, a faculty member from the University of Hawaiʻi with a passion for channel swimming has published a study that sheds light on the rare interactions between cookiecutter sharks (Isistius brasiliensis) and humans. Minaglia is an associate professor of obstetrics, gynaecology, and women’s health at the John A. Burns School of Medicine, and reveals how environmental factors can elevate the chances of being bitten.
The study, spanning 66 marine reserves across 37 countries worldwide, sheds light on the stark contrast in shark abundance between fully protected zones and areas open to industrial fishing. Reef-dwelling species such as Caribbean reef, grey reef, whitetip reef, and nurse sharks exhibited nearly double the population density within fully protected marine reserves compared to fishing-permitted zones.
