By Colin Thackray, Nereus Fellow at Harvard University
It’s fairly common knowledge that tuna is high in methylmercury, a neurotoxin that bioaccumulates in marine food webs. This means that methylmercury magnifies further up the food web – tuna eat smaller fish that eat even smaller fish or plankton — all of which could contain the contaminant.
Nereus Fellow, Rachel Seary, a PhD Student at the University of Cambridge and the United Nations Environment World Conservation Monitoring Centre, has just returned from Cambodia, where she conducted a month long fieldwork period aimed at understanding the links between mangroves and fishing community livelihoods.
By Robert Blasiak, Nereus Program Fellow at Stockholm University
Let’s turn the clock back 113 years. The prominent German zoologist Franz Doflein is about to embark on a two-year journey with the dream of becoming one of the first scientists to study the marine flora and fauna of the deep-sea trenches off the coast of Japan. Reports that the Japanese and Russian empires have just declared war on each other are troubling, yet months of preparation cannot be abandoned, and in the summer of 1904, he boards the Prince Heinrich, a steamship bound for East Asia.
The high seas — also called international waters — comprise 64% of the world’s oceans and 45% of the earth’s surface. They are shared by the world but governed by no one country. That means that the incredible biodiversity of the high seas, from seaweeds to fish to sharks, is not currently protected.
By Colin Thackray, Nereus Fellow at Harvard University
The oceans are very expansive. Their enormous size and distance from where people stay long term presents a challenge for scientists monitoring the oceans. Unlike many atmospheric measurements for meteorology which we can make just outside of cities, often at airports, to get good measurements for ocean science, a journey on the sea is often required. Around the world, there are many ships designed or outfitted specifically for bringing scientists to the ocean – so called Research Vessels (RVs).
The global oceans provide hundreds of millions of people with livelihoods, food and nutritional security, and are crucial for employment, economic development, and export earnings in many countries and coastal communities around the world. The status of these important ecosystems and its fisheries resources are however rapidly declining, following decades of unsustainable exploitation patterns, overcapacity, and unsuccessful governance interventions.
The world is intuitively divided by the existence of recognizable, bounded units of landscape with characteristic climatic regimes and land cover that drives the distribution of existing life on earth. On a global scale, terrestrial ecosystems are grouped into major biomes such as boreal forest, savannah, desert, tundra and grasslands, each with distinct climates, landscapes, species, and vegetation.
Any trip to an aquarium or seafood market reveals the incredible variety of fishes. These fishes not only differ in how they look, but in traits related to life history. Life history traits include maximum body size, longevity, age at maturity, and fecundity – the number of eggs produced. Fishes that have the same phylogeny, or evolutionary history, share similar traits. Conversely, unrelated fishes occasionally evolve similar traits independently.
A meadow under the sea? Not to be confused with seaweeds, seagrasses are land plants that have adapted to living their entire lives submerged in saltwater. They are close relatives of terrestrial grasses, seagrasses are thought to have colonized marine environments several millions of years ago. Different species of seagrass are found in tropic and temperate regions around the world from Southeast Asia to Scandinavia and all around North America. They are known as a “foundation species” because they create important habitat for a wide array of other organisms.
By Richard Caddell, Nereus Program Fellow at Utrecht University
It is increasingly evident that profound changes will be necessary to current fishing practices in order to meet future global demand for seafood. Many fisheries are already operating at or beyond their ecological and economic capacity, while climate change and associated processes are projected to have significant impacts upon the future distribution of fish stocks.
