Having lice is one of life’s lower moments. It causes much wailing, rending of garments, purchasing of funny little combs, and a crushing feeling of ickiness. But lice are common in the animal kingdom, afflicting everything from a teensy mouse to one of Earth’s most majestic creatures, the humpback whale. Amorina Kingdon, Hakai Magazine
I’ve had cases of larval sea lice and the sting of the man-of-war. If you swim in the waters of Florida and the Caribbean, you know that sea lice hide in sargassum. A seaweed that, thanks to heavy fertilizer use in Brazil’s Amazon River basin, is transported by ocean currents to the Sargassum Sea that slowly covers Florida and beaches in smothering sea lice-infested mats of the seaweed. Daily Kos blogger Denise Oliver Velez wrote a recommended diary in her Caribbean Matters series. The bite of a sea louse usually occurs on the genitals, where they get trapped in a swimmer's bathing suit.
My diary is not about that particular sea louse that has made me miserable on several occasions; rather, the Lepeophtheirus salmonis louse that feeds on salmon skin mucus, tissues, and blood.
It is a natural process, and the species affects both the Atlantic and Pacific salmon. Fish get lice, but it is a rare occurrence where generally only a few bites would affect the fish, not kill it.
Climate change has increased the risk of death due to record warm sea temperatures in the northern hemisphere in what should be cold ocean water. It is a worrying development not only due to a warming climate but also because earth systems, such as the atmosphere, soils, water, cryosphere, biodiversity, and degradation of the geosphere, are shutting down.
One of the worst salmon infestations has occurred off of Western Scotland, where salmon farms provide the United Kingdom’s (already plagued by food shortages from climate change) grocery markets and dining establishments with fish containing key nutrients, such as selenium, phosphorus, and B vitamins. It is one of the most nutritious foods on earth. Seafood Source reported that 1.2 million farmed salmon were culled in Scotland due to lice and jellyfish. The lice can infect wild salmon when they swim too close to these farms. Marine life is commonly used as feed for the salmon, further traumatizing ocean ecosystems where exploitation takes place out-of-sight and in mind under the ocean surface.
Viva writes:
Monstrous sea lice and jellyfish invasions blighting Scottish salmon farms
Investigators for Viva! Campaigns – monitoring five salmon farms in the Scottish Highlands around Loch Carron, Loch Kishorn and Loch Torridon – have captured monstrous footage of Atlantic salmon being eaten alive by invasions of parasitic sea lice. Some sea cages were also found to be surrounded by large blooms of jellyfish, further threatening the health and wellbeing of farmed salmon, as well as wild species.
All five farms are members of the RSPCA Assured certification scheme and both Torridon and West Strome (in Loch Carron) are approved by the Aquaculture Stewardship Council (ASC). They are contracted to three of the largest producers of Atlantic salmon, supplying Asda, Co-op, M&S, Sainsbury’s and Tesco.
More images from the investigation can also be publicly viewed on Flickr.
Salmon farms operated by Bakkafrost (West Strome in Loch Carron), Scottish Sea Farms (Kishorn North, South and West in Loch Kishorn) and Mowi (Torridon in Loch Torridon) were all found battling high levels of sea lice, as well as complex gill and bacterial disease, requiring chemical (usually hydrogen peroxide) and freshwater treatments.
The article below has been republished from the Creative Commons site, The Conversation.
Jellyfish alert: increased sightings signal dramatic changes in ocean food web due to climate change
Abigail McQuatters-Gollop, University of Plymouth
Did you see a jellyfish on a recent trip to the seaside? UK beachgoers are more likely to spot one now than in the past, as rising sea temperatures due to climate change have ushered more of these gelatinous animals into the waters around northern Europe.
Jellyfish don’t swim like fish. They belong to the plankton: a diverse group of marine creatures that drift through the sea, floating wherever the currents take them. Jellyfish are among the few types of plankton visible to the human eye. Most plankton are tiny (smaller than 2mm) and can only be seen with a microscope.
Although largely invisible, plankton are the base of the ocean food web, eaten by fish, seabirds and even whales. Species that don’t eat plankton, like seals, will eat organisms that do. Globally, phytoplankton (single-celled algae which, like trees and shrubs on land, are mostly green in colour and use chlorophyll to photosynthesise) produce half of the oxygen we breathe.
Increasingly abundant jellyfish are just one example of the many ways that plankton are reflecting climate change’s influence on the ocean. My research team has found that the species making up North Atlantic plankton communities are also shifting as sea temperatures rise.
We analysed plankton data collected using nets and bottles throughout the northeast Atlantic over the past 80 years. We found that the larvae of crabs, starfish, sea urchins and lobsters are becoming more common, while shrimp-like crustaceans called copepods (a critical food source for fish, seabirds and even basking sharks) are declining.
These are big changes among some of the smallest forms of life, and they will affect the entire marine food web, as well as humans. We must understand these changes in order to adapt to them. That could mean new fishing practices – and even diets.
In a jellyfish’s wake
Zooplankton (the animal subset of plankton) consists not only of copepods and jellyfish, but also the larval stages of fish, crustaceans and echinoderms (the “spiny skin” group that starfish and sea urchins belong to) which later settle to the sea floor and mature into their familiar adult forms. Both zooplankton and phytoplankton communities are highly diverse, containing species of all sorts of weird and wonderful shapes.
Since the 1960s, colder-water zooplankton species have been retreating towards the Arctic, followed by warmer-water species that are also tracking rising sea temperatures northwards. The warmer-water zooplankton species which now dominate northern European waters are generally smaller and less nutritious than the cold-water species they have replaced.
The seasonal timing of when plankton are abundant in the North Sea has also shifted, including around the UK. While the seasonal cycle of phytoplankton is driven by sunlight and so hasn’t changed, the point in the year when some zooplankton species are most abundant now arrives earlier, as shorter and warmer winters cause the eggs of some species to hatch sooner. This has meant a mismatch between the spring phytoplankton bloom and the annual peak abundance of the zooplankton that gorge on it.
These shifts have meant the quantity and type of food available to larval fish (which are zooplankton themselves but eat smaller zooplankton) is changing in the North Atlantic. Warm-water species such as bluefin tuna and anchovies are now commonly found in northern European waters, while cod, herring, whiting and sprat, all important commercial fish species, have declined in number.
Fishery managers need to work with scientists to set quotas that ensure these new species are fished sustainably, while coastal fishing communities may have to catch new species as familiar ones decline. The public may have to adapt their diets too as traditional species, such as cod in the UK, become scarcer.
The jellyfish you now see in UK waters might have once been a rarity, but it’s following a (largely invisible) crowd that is upending marine food webs and changing the kind of fish you might buy and eat locally. The next time you watch the hypnotic motion of one of these beautiful creatures as it pulses through the water, think of the changes its arrival portends, both for the ocean and yourself.
Abigail McQuatters-Gollop, Associate Professor of Marine Conservation, University of Plymouth
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Warmer waters, in turn, mean less oxygen. This double whammy severely hurts many marine creatures, like coral, but not jellies. In mid-latitudes, in fact, higher water temperatures lead jelly embryos and larvae to develop more quickly, and the animals enjoy longer reproductive periods, according to Inside Climate News.
Topics covered in the article:
Jellies are already good at reproducing. A breeding female nettle, for example, can spawn 45,000 eggs per day, according to Smithsonian Magazine. When inland rivers carry fertilizer run-off from agriculture to coastal waters, that can create competition-free buffets for jellies. Overfishing is also fueling the global jellyfish proliferation. A 2012 study from the University of British Columbia concluded that "jellyfish populations appear to be increasing in the majority of the world's coastal ecosystems and seas." In 2011, jellyfish overwhelmed the cooling system at a coal power plant near Hadera, Israel. Jellyfish swarms can also be deadly for other marine creatures.Overall, mounting evidence suggests, underwater ecosystem may be changing from one dominated by fish to one ruled by jellies. This is — in part — a situation of own making: A 2009 study noted that human-induced stresses, including overfishing, climate change, and habitat modification, "appear to be promoting jellyfish blooms to the detriment of other marine organisms."