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
Marine protected areas (MPAs) are pretty nifty tools for marine conservation. You take an area, you give it a designations and (hopefully… but the reality can be quite different) you attach some regulations/legislation to remove harmful activities to whatever it is you are trying to protect inside the MPA and make efforts to rebuild and conserve this spot. The situation of picking an area to designate can become trickier when dealing with ocean wanderers – species that move around a lot, and over great distances. It is safe to say that it is politically unfeasible to designate one area big enough to encompass, for example the movement of sea turtles. Instead, sea turtles may find critical habitat – feeding areas or nesting beaches for instance, covered by an MPA. We can’t protect them everywhere, but we can build a case to protect them where we know they hang out in large numbers. Some species are a little less predictable – or we simply don’t know where their critical areas are. Take southern Kenya’s populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) for instance. Apparently these critters are the most abundant of the marine mammals in Kenya’s Kisite-Mpunguti MPA. Abundance does not mean we know much about them though. The species is listed as data deficient on the IUCN Red List. Continue reading Protecting Kenya’s dolphin habitat
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
Australia has, compared to some other countries, a fairly extensive network of both marine and terrestrial protected areas. On the marine side there is of course the Great Barrier Reef Marine Park and more recently the implementation of the Commonwealth Marine Reserve network. The idea behind any marine protected area is to offer long term “conservation of nature with associated ecosystem services and cultural values”, so one would expect to see some effective protection going on in these areas…right? Areas chosen, and cared for to ensure they offer conservation value, to do all we can to help keep species going that have suffered population declines because of our actions? I’m sure many of you won’t be surprised to hear that this isn’t always the case. Take a look at some of my previous posts over on Google Plus – here, here, and here for example. Unfortunately, as highlighted in a recent study by Karen Devitt, who was based at Charles Darwin University, Australia’s protected areas are inadequate for protecting one of the world’s most threatened marine fishes – the sawfish.
Continue reading Australia’s protected area network fails to adequately protect the world’s most threatened marine fishes
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)
A casual glance at the ocean and you may just see a mass of blue. But take a closer look. There are waves, different colours, and different levels of water clarity. If you could peel back the layer of water, you would see environments that are not entirely alien – like mountains, canyons, forests, grass meadows, sand, mud, and volcanoes. The ocean is a mosaic of the most wondrous and splendid habitats, hosting a magnificent array of life. Whilst the terrain itself may remain fairly stable, the ocean itself moves. It’s not just the waves you can see breaking on the beach, nor the movement of the tides, or even those rip currents you really don’t want to find yourself stuck in. Beneath the surface, you will also find movement like currents flowing at different depths, upwellings that bring cold, nutrient rich waters to the surface, and internal waves as tall as 244 meters. Sometimes you get two water masses moving either towards or way from each other, creating oceanic fronts.
Broadly speaking there are two types of oceanic fronts. Convergent fronts occur when the masses move towards each other. Here the water tends to be warmer than the surrounding area, and accumulate all sorts of marine critters, algae, and even litter. In divergent fronts, where the water masses are moving away from each other, upwellings are created bringing up nutrients from the deep. These nutrients support phytoplankton growth, which in turn supports zooplankton, which in turn supports other marine life – including species under threat, and species we like to eat. The thing about fronts (as with many oceanographic features) is that they are not necessarily permanent features that remain in the same place. The ocean is dynamic and as a result the habitat for many critters that live in the water column is also dynamic.
Continue reading The ocean moves – and so should marine conservation management
Reaching up to 5.5 meters in length, the reef manta ray ( Manta alfredi ) is the second largest species of ray in the world. As a group, rays are highly threatened and the reef manta ray is no exception. Already listed as vulnerable on the IUCN Red List, it is thought that the global population of the reef manta is in decline. The threats to the ray primarily come from fisheries that target them for their meat, fins, and the aquarium trade, but they are also at risk from being struck by boats, and from becoming entangled in fishing gear, line lines and nets. These critters need our help if their population is to stop declining. Protecting mantas isn’t just important for the manta’s themselves, or even the wider food web of which they are a part. Manta’s are captivating creatures, so much so that in some places in the world, manta’s drive a tourism industry all of their own. Indonesia has the fourth highest number of manta ray tourism sites in the world, bringing in an estimated U$15 million a year to the Indonesia economy. Indonesia also happens to be home to a substantial manta-targeting fishery which brings in around $442,000 a year.
Continue reading Where the reef manta doth roam