This little critter is a limpet. From the photo they may not look like the most exciting of creatures. If you’ve ever been down to the coast and taken a look at them yourself… your opinion may not have changed. They don’t seem to move around a lot, or do a lot. Of course looks can be deceiving. Under that shell is the limpet’s squishy body – and their big, muscular foot which, alongside a pretty amazing adhesive secretion, they use to cling onto rocks and other hard surfaces. Anyone who has ever had a go at trying to get a limpet off a rock knows how good a grip they can have. This fabulous foot isn’t just used to stop them from drying out when the tide leaves them exposed to the air, or keep pesky predators (or nosy humans) at bay. Limpets are grazers, feeding on tiny algae on the surface of rocks with their raspy “tongue” (called a radula). See that empty space behind the limpet in the photo? That’s where it’s been grazing. Once they have grazed an area they need to find more food. That foot gets to work, and along moves the limpet, munching up all the algae in its path. Some limpet species even appear to have a home – a particular crevice that they return to just before the tide will expose them to the air.
But this isn’t a post about how amazing limpets are. This is a post about animal movements in the ocean.. Or at least 3 different types of animal movement. Some of them move a lot further than you think. Yes, even limpets.
Continue reading Just keep swimming
In my last post I mentioned that I am starting a PhD. I promised to tell you a little more about what my research will be looking at, so here we go!
The project outline
My research comes very broadly defined already – the work’s raison d’être if you like. Here it is:
“Movement and dispersal connects marine populations, allowing restoration of depleted local populations by immigrants that renew genetic diversity. Although Canada’s Oceans Act prioritizes ‘linking Canada’s network of marine protected areas (MPA)’, connectivity has not weighed significantly in MPA network design in Canada. This study will optimize regional marine connectivity among protected areas in the Atlantic region by determining optimal locations for new MPAs and evaluating how commercially important species would be representative in the entire MPA network. To model species distribution based on larval dispersal, fishery pressure, and climate change, we will use 3-D ocean circulation models. Then, based on metapopulation theory, we will develop novel spatial network algorithms to optimise the number and spatial connectivity between MPAs under current and future scenarios of climate and fishery pressure that may alter larval supply”.
Sounds complex? Yep, for me too. Continue reading Where the wild things roam: Dispersal, connectivity, marine protected areas, and my PhD project
Hello my fellow readers
You may have noticed that I have been away for some time. Some of you have even gotten in contact with me to find out why, and encourage me back – thank you! Your words of kindness and encouragement were very much appreciated. I honestly did not mean to disappear for so long, but I did get incredibly busy. I thought I’d share with you all some of the questions I’ve been asked during my time away – and my responses! Continue reading On being MIA – and what’s next
At 9 foot long, not including the tail, tiger shark (Galeocerdo cuvier) Harry Lindo is not exactly on the small side. It’s not Harry’s size that is exciting scientists and shark enthusiasts, nor a photograph taken in 2009 by Ian Card showing a shark – suspected to be Harry, trying to eat a 150 lb juvenile tiger shark off the coast of Bermuda. Between 2009 and 2012 researchers tagged 24 tiger sharks with satellite transmitters in the Challenger Bank, which lies just off Bermuda in the Atlantic Ocean. In study lead by James Lea (The Guy Harvey Research Institute, Nova Southeastern University Oceanographic Center) and team of international collaborators, those shark movements have been compiled and analysed. Harry, it turns out, is one heck of an ocean wanderer. In just over 3 years Harry swam over 44,000 kilometres – that’s more than the circumference of the Earth (just over 40,000 kilometres). Harry’s track is the longest recorded for a tiger shark, and probably the longest ever published for any shark species.
Continue reading The travelling life of the tiger shark
We all have our favourite types of environment and weather. Some love those warm, sunny days spent on a beach of golden sands. Some love those rainy days in the forest, when everything glistens with the raindrops. Some love nothing more than a cold crisp day in snowy mountains. We humans are lucky. We can not only survive but enjoy a wealth of different environmental conditions. Many other species are not so adaptive. In the oceans some creatures live in the seabed itself, others on top. Some may stay in the water column dominated by a particular type of habitat like a kelp forest, whilst others roam into a variety of different locations throughout their lives. Then there are the varying conditions of the ocean itself. Some areas are generally calm whilst others may experience a lot of movement. Salinity levels also vary, as does oxygen, as does temperature. Actually temperature – as many a fisher will know – is a super important driver of species distribution. There are a few reasons for this. First, unlike us, most fish do not have the ability to control their own body temperature. Their internal body temperature reflects that of the environment they are in. The second primary reason relates to food. If the major food of a fish – be it plant (phytoplankton) or animal – changes its abundance (how many) or its distribution (where it is), then the fish may follow. Continue reading With ever-warming waters, some European fish are on the move
With rapidly warming ocean regions comes changes in marine species distributions. Understanding and monitoring these changes is important for managing biosecurity threats as well as management of existing and changing living marine resources. Detecting range changes in the marine environment is difficult and expensive. For many species, assessment simply has not taken place. To combat this data gap and assist managers in directing limited research resources, Dr Lucy Robinson, research fellow at the Institute for Marine and Antarctic Studies (IMAS) and colleagues suggest a new method – rapid screening assessment that uses a variety of sources.
Development of the method, which was recently published in Global Environmental Change , focused on waters off the east coast of Tasmania, and area where over the past 50 years warming has been nearly four times greater than the global average. Using field data from a number of sources, primarily from the citizen science program Redmap Australia, 47 species were assessed for range expansion. Categorising species based on confidence in their range expansion, 8 species – 6 fish species, a lobster and an octopus species – were categorised with a ‘‘high’’ confidence of potentially extending their ranges. These species, the researchers argue, are the ones that should be prioritised for impact assessment, with those falling in the “medium” and “low” confidence categories coming after.
The paper is behind a paywall, but if you have access (or want to buy a copy) you can find it here http://dx.doi.org/10.1016/j.gloenvcha.2014.12.003
Image: The rainbow cale (Heteroscarus acroptilus) is one of the species assessed in this study. The assessment had “high” confidence in a potential range extension for this beautiful fish. This particular beauty is a male in breeding colouration. Credit Richard Ling/Flickr (CC BY-NC-ND 2.0)
This little chap is a Sally Lightfoot crab (Grapsus grapsus). Sally Lightfoot’s can be found on the west coast of South America, Central America, and Mexico, but this critter in particular lives on the Galápagos Islands – or as they are officially known Archipiélago de Colón. These islands are home to 95 living endemics species (species found nowhere else), and famed for the now-deceased giant tortoise ‘Lonesome George’ and Charles Darwin’s work on Galapagos mockingbirds and finches which eventually gave rise to his seminal book On the Origin of Species as well as its biodiversity and outstanding beauty both on land and in its seas. Unfortunately for our Sally Lightfoot, those seas are due to get warmer….a lot warmer. Continue reading Ocean warming hotspots
Whoa there little fella where do you think your trying to hitch a ride off to?
Actually, he’s not the only one on the move. Elvira Poloczanska from CSIRO, and plethora of colleagues around the globe have been very busy bees over the past 3 years, assembling a database of a whopping 1,735 recorded changes in marine biological responses (distribution, phenology, community composition, abundance, demography, and calcification). These changes come from a whole range of species from around the globe. How far back data went varied, timespan averaged at around 40 years (so back to the 1970s. I believe this is roughly around/just after Scuba diving started to become more main-stream). So what did they find? Well, out of all the changes, 81–83% of them were consistent with climate change. Here’s two of the ‘headline’ changes that came out of this study… Continue reading Warming waters means many marine species are on the move