Tag Archives: fish

Incompetent Invaders Dilute Parasites and Alter Disease Dynamics

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Guest post by Paula Tierney

Invasive freshwater fish (Leuciscus leuciscus) acts as a sink for a parasite of native brown trout Salmo trutta (2020) Tierney et al. Biological Invasions. https://doi.org/10.1007/s10530-020-02253-1

The Crux

From house cats to cane toads, invasive species are one of the biggest threats worldwide to native plants and wildlife, second only to habitat destruction. There are a few different definitions of an invasive species, but two consistent tenets are a) that they are a living organism spreading and forming new populations outside of their native range and b) causing some kind of damage to the native ecosystem, economy or human health. As humans move around the globe with increasing ease (these last two months aside), the spreading of invasive species is increasingly common in our globalised world.

The spread of invasive species creates new ecological interactions between native and invasive species that can impact how our native ecosystems function, including disease dynamics. One key set of interactions that can be completely changed by the introduction of the invader are that of parasites and their hosts. If development and transmission of native parasites is different in invasive hosts compared to their usual native hosts, the parasite dynamics of the whole system can be altered.

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Water-Based Recreation Can Promote Non-Native Introductions

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Image Credit: Manfred Antranias Zimmer, Pixabay licence, Image Cropped

Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity (2019) Chapman et al., Global Ecology and Biogeography, https://doi.org/10.1111/geb.13051

The Crux

The spread of invasive species throughout freshwater ecosystems is a topic we’ve looked at before on Ecology for the Masses. In a previous paper breakdown we talked about how recreational is heavily responsible for the presence of non-native fish at a European scale.

Our paper this week takes a more local approach. Can we predict the presence of non-native birds, invertebrates and fish by looking at the presence of human activity, and where that human activity is present?

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When the Growing Gets Hot

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Growth is a critical aspect of life for all organisms, and understanding what can and cannot affect it allows us to predict what effect climate change may have on organisms like these zebrafish (Image Credit: Lynn Ketchum, CC BY-SA 2.0).

Warming increases the cost of growth in a model vertebrate (2019) Barneche et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13348

The Crux

In ecology, how organisms grow is relevant across all levels of life. Growing faster than others can be selected for as an evolutionary advantage, if being bigger earlier means that you have a competitive advantage over other members of your species.

Because growth is so critical to life, it is important to understand what may affect the ability of an organism to grow. The only way an organism can grow is by converting energy it acquires from food to its own body mass, but outside influences, like temperature, can affect how efficient an organism is at this energy conversion. The authors of today’s paper wanted to investigate if this efficiency and the cost of growth itself changed across a range of projected temperatures.
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Life Under Lake Ice: A Mysterious (and Threatened) World

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Image Credit: US National Park Service, Public Domain Mark 1.0, Image Cropped

Ice has become (pardon the pun) something of a hot topic lately.

Professional and amateur scientists alike have studied the timing of seasonal ice formation on lakes and rivers for hundreds of years, and the patterns that have emerged from these studies provide a window into the progression of climate change. Overwhelmingly, the data show that lakes and rivers are freezing up later in the winter and their ice cover is melting earlier in the spring than in the past.

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Does Invading Change You?

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The red lionfish, an aggressive, fecund, and competitive species invasive to the Atlantic Ocean (Image Credit: Alexander Vasenin, CC BY-SA 3.0, Image Cropped).

The genomics of invasion: characterization of red lionfish (Pterois volitans) populations from the native and introduced ranges (2019) Burford Reiskind et al., Biological Invasions, https://doi.org/10.1007/s10530-019-01992-0(0123456789

The Crux

Invasive species are one of the most destructive forces and largest threats to native ecosystems, second only to habitat loss. The “how” and “when” of a species invading new habitats is obviously important, and as such many studies focus on if invasive species are present and if they are spreading. Yet these studies often disregard the mechanisms behind why a species is spreading or succeeding in these new environments. The mechanisms are important here, because by and large most invasive organisms will have very small populations sizes, leaving them vulnerable to stochastic events like environmental flux, disease, and inbreeding depression.

Two key paradoxes of invasive species are that these small groups of invasive organisms tend to not only have more genetic diversity than the native species (making them more adaptable to environmental change), but they are also able to outcompete the native organisms, despite having evolved in and adapted to what may be a completely different environment. The authors of this study used genomic approaches to address and try to understand these paradoxes.  Read more

The Ecology of a Mermaid

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Image Credit: The Little Mermaid, 1989

Adam regales us with one of the weirdest stories I’ve ever heard, and in case you were wondering, yes we do talk about how mermaids have sex. Jesus. Also there’s some cool ecology. Like how did mermaids evolve? Was it from a mutated baby tossed overboard? Probably not.

05:19 – Mermaids in Cinema
16:35 – Ecology of the Mermaids
33:25 – Mermaid Copulation (you were warned)
38:07 – The Mermaids vs. Jaws

You can also find us on iTunes and Google Play.

Finished Before You Even Started

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Predators are known to affect prey while they are adults and juveniles, but what about when they haven’t even hatched yet?  (Image Credit: Mark Jones, CC BY 2.0, Image Cropped)

Predation risk affects egg mortality and carry over effects in the larval stages in damselflies (2018) Sniegula et al., Freshwater Biology, p. 1-9

The Crux

In the natural world, one of the most dangerous things that a prey animal has to worry about is a predator. These organisms depend on the prey for their sustenance, and as such have become very good at finding ways to eat them. These are known as direct effects, as a predator eating prey is a direct interaction.

Another aspect of the predator-prey relationship is that of indirect effects, or effects that a predator has on prey that don’t involve it eating the prey animal. These can include predator-induced changes in the prey’s behavior, immune function, or even survival. These indirect effects are usually studied in prey species that are adults or juveniles, but the authors of today’s paper were interested in what indirect effects predators had on the eggs of prey species.

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How to Ecology Your Dragon

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Image Credit: DreamWorks Dragons, 2012

In our second week on the dragons of Dreamworks’ How to Train Your Dragon trilogy, we have a flamin’ good time discovering why those dragons are WAY too wacky, exactly how much intraspecies predation goes on in Berk and why you should really make up your mind about domestication.

03:49 – Vikings in Cinema
10:57 – Ecology of the Dragons
29:17 – Toothless vs. the Furious Five

You can also find us on iTunes and Google Play.

Fishers and Fish Science: The Australian Fish Scientist Perspective

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Fishing is an important part of Australian society. So is communication between fish scientists and fishers strong enough?

Fishing is an important part of Australian society. So is communication between fish scientists and fishers strong enough? (Image Credit: State Library of Queensland, Image Cropped)

Last Thursday, I posted an article on the need for more contact communication the fish scientist community and the fishing community, which you can find here. It gives a breakdown of why better communication between the two groups is mutually beneficial, and how it could be improved. The piece was written after talks with a number of prominent Australian fish biologists, whose thoughts I’ve shared in more detail below.

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