We submerge ourselves into the murky depths of what is clearly a backyard pool and meet… yet another man in a suit. This week is all about the Gillman from 1712’s The Creature from the Black Lagoon. Dave and Adam both need more bloody caffeine.
4:29 – Movie History
14:23 – Physiology of the Gillman
37:51 – Ecology of the Gillman
1:01:56 – The Gillman vs. Richard Strickland from The Shape of Water
When we monitor the fluctuations of a population, we often look at vital rates, a huge part of which is reproductive success. The success that males have in siring offspring can be hugely influenced by the density of a population, particularly when it comes to a breeding ground.
Larger males will often outcompete smaller males on such grounds, however in many species these males will often reach reproductive limits, at which point smaller males can benefit. Smaller males may also fare better in less dense populations, where females lack other individuals to compare them to. Our study today looks at variations in reproductive success of a nest-breeding fish species over two levels of density.
With this in mind, marine biologist Gretta Pecl founded the Range Extension Database and Mapping project, also known as Redmap. Redmap aggregates public sightings of fish to show shifts in the distributions of Australia’s marine species, including some that are crucial to our fishers. At the recent ASFB 2018 conference, I sat down with Gretta to talk about changes in marine species distributions, how they’ll affect Australia, and how they might help the public understand the effects of climate change.
The Australian government has been throwing around the term Carpageddon for a while now. So why is it a problem? (Image Credit: Ed Dunens, CC BY 2.0)
Species richness is much higher in waters near the equator, but do we see that in a phylogenetic tree? (Image Credit: Rich Brooks, CC BY 2.0)
An inverse latitudinal gradient in speciation rate for marine fishes (2018) Rabosky et al., Nature doi:10.1038/s41586-018-0273-1
The tropical regions of the Earth are the most species-rich and diverse ecosystems on the planet, with this diversity and species-richness declining as you move further and further from the equator. One hypothesis explaining this is that speciation rates are simply higher in the tropics, meaning that more species are evolving in a given time in the tropics than anywhere else. To test for this, the authors used the largest phylogenetic tree available and analyzed speciation rates (how many new species evolve from older species) per million years.
Normally three spined sticklebacks are less likely to find a mate when they are affected with parasites, but does this change with eutrophication? (Image Credit: Sam Perrin, NTNU)
Reversed parasite-mediated selection in sticklebacks from eutrophied habitats (2010) Heuschele & Candolin, Behavioral Ecology and Sociobiology DOI: 10.1007/s00265-010-0937-9
We’ve all heard the stories of turtles choking on plastic bags, or birds swallowing sporks. Algae grows out of control due to chemicals being added to the water, which changes the native habitat. For fish like sticklebacks, where males compete for the attention of females, the loss of visibility has the potential to be a problem for the females. Male sticklebacks defend a territory, develop a bright red spot, and fight other males. The long and short of it is that the bigger, stronger, and prettier fish mate more and the weaker and uglier fish don’t. One thing that weaker males tend to have more of than stronger males are parasites, which isn’t a surprise as a parasite’s entire existence revolves around surviving at the expense of whatever organism is unfortunate enough to have them.
Understanding how eutrophication affects female choice in relation to parasites, and thus the reproductive dynamics of this system, is quite important. This paper tries to map that out, using the Baltic Sea around Southern Finland. This experiment is well-suited to the problem, as there has already been evidence for algal growth changing the dynamics of stickleback reproduction.
Lake Superior, the location of the 9th International Charr Symposium (Image Credit: Wikipedia Commons)
