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.
For fish and other water-breathing animals like sharks and rays, reaching reproductive maturity is a crucial milestone that impacts their entire life history. The size at which they reach maturity, coupled with their subsequent growth rate, affects their longevity and reproductive capacity. Now, researchers have pinpointed a specific pH threshold, termed the "reproductive respiration threshold" (RRT), which kickstarts the hormonal processes leading to maturation.
Unveiled by an international team of archaeologists and palaeontologists, this finding provides an intriguing glimpse into the ancient seas and the life of a previously unknown apex predator of the Late Cretaceous period.
This remarkable finding, uncovered during a recent expedition led by Greenpeace, has piqued considerable intrigue among scientists owing to the rarity of smooth hammerhead shark sightings during their early developmental stages.
According to the findings, more than half of the 208 non-target species ensnared in the nets over the past eight months met a grim fate, with 134 animals, including critically endangered grey nurse sharks and leatherback turtles, among the casualties. The figures, made public as the nets were removed for the season, highlight the significant toll the program exacts on marine biodiversity.
The groundbreaking study delved into the drivers behind how juvenile white sharks move. Using special tracking technology that listens to the sharks and tracks their positions, the team of scientists, led by Emily Spurgeon, gathered detailed information about how the varying temperatures of the layers of the sea affect their travels.
Conventionally, shark behaviour has been perceived as largely instinctive and uniform across individuals. However, a team of researchers, led by Thomas M. Vignaud, have upended this notion, uncovering a spectrum of individual personalities among bull sharks frequenting feeding sites.
William T. White and his team of researchers described the distinct characteristics of the Roughback Bristle Shark through meticulous examination of its size, coloring, body structure, texture, dental arrangement, egg cases, and genetic makeup, and published their their study in the journal "Fishes." Residing at astonishing depths between 2,200 feet and 3,900 feet, the newfound shark species has, thus far, exclusively inhabited the waters off the western coast of New Zealand's North Island.
The hypothesis has been questioned in a recent study by Dr. Eric E.G. Clua and Dr. Carl G. Meyer, published in a Special Issue of the journal Behaviour. They point out that not only is it unsupported by the evidence, but it fails to stand up to close scrutiny.
For years, the Shark Lab at California State University, Long Beach, has been at the forefront of research, tracking shark movements and behaviour, which has been crucial for beach safety and conservation efforts. The loss of funding could severely hinder these vital studies, potentially impacting both ecological understanding and public welfare.
