White oval squid (Sepioteuthis lessoniana sp. 2), known locally as shiro-ika, are medium-sized squids naturally distributed in the Indian and western Pacific oceans, flittering in and out of a wide range of different habitats – from shallow seagrass beds, over coral reefs, to depths of 100m along coastal environments. In such biodiverse zones, the squids encounter predators of all sizes and shapes, from seabirds flying overhead to sharks, tuna, and other cephalopods prowling under the sea.

Such a variety of threats calls for a large repertoire of survival strategies. Researchers from the Okinawan Institute of Science and Technology (OIST) have previously discovered how shiro-ika change color when moving between different shades of substrate – and now, the same team has painted a full picture of how the cephalopod employs a sophisticated range of camouflaging strategies to adapt to different environments and threats. “The wide variety of visual strategies used by the squid is surprisingly complex, especially considering that squid have traditionally been regarded as spending most of their lives in the open water column,” explains former OIST Visiting Researcher Dr. Ryuta Nakajima, “This discovery suggests that squid have a deeper behavioral relationship with the ocean floor than previously thought.”

Around 115 million years ago, the seas off northern Australia were home to a gigantic ancestor of Jaws. Fossils of this ancient mega-predator reveal that modern sharks experimented with enormous body sizes much earlier in their evolutionary history than previously suspected, and took the top place in oceanic food chains alongside massive marine reptiles during the Age of Dinosaurs. This study presents a new interdisciplinary analysis to reconstruct size evolution in ancient sharks.   

A team of international researchers led by the University of Vienna investigated the development of shark and ray biodiversity over the past 100 million years. Their surprising results show a continuous decline in diversity since the Eocene, 45 million years ago, which contradicts previous assumptions that biodiversity was either stable or increasing. This study, recently published in the renowned journal Scientific Reports, provides crucial insights for modern marine conservation.

More than 30,000 teeth, bones and other fossils from a 249 million-year-old community of extinct marine reptiles, amphibians, bony fish and sharks have been discovered on the remote Arctic island of Spitsbergen. These record the earliest radiation of land-living animals into oceanic ecosystems following cataclysmic extinction and extreme global warming at the dawn of the Age of Dinosaurs.

 

A new study finds that the illegal trade of fins from four threatened shark species persisted in the Hong Kong market from 2015 to 2021. The analysis uncovers a substantial discrepancy between international records of fin exports and reality, with implications for fisheries regulation and management. In 2013, five overexploited shark species were listed on Appendix II of the Convention on International Trade of Endangered Species (CITES): The scalloped hammerhead (Sphyrna lewini), smooth hammerhead (S. zygaena), great hammerhead (S. mokarran), oceanic whitetip (Carcharhinus longimanus), and porbeagle (Lamna nasus). Since then, unreported and uncertified exports of fins from the species have been illegal. Building upon their 2024 Science Advances study, which characterized the illegal trade of small-sized shark species’ fins in Hong Kong (see below), Diego Cardeñosa and colleagues have now examined the evolution of illegal fin trade for these five threatened species in the Hong Kong fin market over nearly a decade. First, they analyzed fin trimmings gathered from 2014 to 2021 and determined that fins from four of the five species – excepting the porbeagle shark – were notably common in the sample set. They scaled this ratio using a statistical model and determined these illegal fins remained ubiquitous in the market from 2015 to 2021. Their findings were at odds with trade records maintained by CITES, indicating rampant illegal trade activity. Next, Cardeñosa et al. estimated how many nations that do not report their species exports were likely contributing fins from the threatened species. They used “DNA zip-coding” to track the four traded species to their originating regions, including those near non-reporting nations. The authors argue it is highly unlikely that large exporters with global industrial fleets known to catch these species are not exporting their fins, citing China, Spain, and Taiwan as examples. They recommend stronger port state measures, implementation of species-level custom codes, and market surveillance through genetic monitoring to provide external support to CITES.

 

For reporters following research on the shark fin trade, a 2024 Science Advances study, coauthored by many of the same authors of the current study, reported that almost 75% of small-sized shark fins and fin trimmings come from smaller species traded in Hong Kong markets: https://www.science.org/doi/10.1126/sciadv.adq6214

A groundbreaking test developed by an FIU scientist can detect small, elusive hammerheads without ever setting eyes on them — a critical new tool for species fighting for survival.

Most sharks in UK waters survive catch-and-release fishing when angling best practices are followed, according to a new study.