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Density distributions of juvenile fish in South Australia - Focusing on the influence of coastal habtitats on climate change-induced range shifts in fish

Sternäng, Märta (2016) BIOY01 20161
Degree Projects in Biology
Popular Abstract
How will baby fish react to global warming?

As most people have been aware of, global warming is just one of many consequences of climate change and increasing CO2-levels in the atmosphere. The oceans are experts at absorbing energy, which makes the ocean temperature rise. In many parts of the world, especially Australia, the sea surface temperatures (SSTs) are increasing rapidly today. This is expected to affect all aspects of the marine world, for example the geographical distribution of fish species. As the ocean gets warmer and warmer, predictions are that fish will have to move pole wards to maintain the living conditions, e.g. the right temperature, in which they normally thrive. Best-case scenario, this would happen without... (More)
How will baby fish react to global warming?

As most people have been aware of, global warming is just one of many consequences of climate change and increasing CO2-levels in the atmosphere. The oceans are experts at absorbing energy, which makes the ocean temperature rise. In many parts of the world, especially Australia, the sea surface temperatures (SSTs) are increasing rapidly today. This is expected to affect all aspects of the marine world, for example the geographical distribution of fish species. As the ocean gets warmer and warmer, predictions are that fish will have to move pole wards to maintain the living conditions, e.g. the right temperature, in which they normally thrive. Best-case scenario, this would happen without difficulties or implications to the surroundings of the fish, but unfortunately this is highly unlikely on the complicated earth on which we live. Ultimately, the requirements of a species may be too many and too geographically unique for that species to escape the warmer temperatures.

Coastal habitats as geographical barriers
There are multiple factors influencing a species’ likelihood to move. One such factor is in which habitat a baby fish likes to spend the early years of its life in. Such a habitat can be a mangrove forest, a saltmarsh or amongst the seagrass on the ocean floor. Juvenile fish tend to stay in these coastal areas while they are growing up because it usually offers more protection than the open water. The problem is that those coastal habitats are expected to move with the rising temperatures much slower than the highly mobile fish. That might result in the fish ending up too far from their most favourable habitat; basically they will have nowhere to go.

To find a method to be able to figure out if the geographical limitations of those coastal habitats might influence the fish from moving south, I collected juvenile fish with a 10m long seine net, at 40 different locations in South Australia. These sites were spread out from north to south along the coast, creating a latitudinal gradient, and situated in either mangrove, saltmarsh, seagrass or in a mudflat. The fishing resulted in 70 different species, of which I studied 22 species further and six of these are represented in the final paper. To be able to draw a conclusion whether or not on the costal habitats can influence the pole ward movement of fish, I constructed graphs (Fig. 1). Those graphs delivered different future scenarios, and I could draw conclusions based on if a species was reliant on a certain habitat or if temperature was
more important for its distribution. By collecting the density information on the different species it was possible to determine which habitats are most important for juvenile fish as well as speculate if a certain species is likely to move south or if it is most likely going to be restricted by the limitations of its favourite habitat, since the habitats will move much slower than the fish.

Handledare: Ivan Nagelkerken, Jan-Åke Nilsson
Examensarbete 30 hp i biologi, vt 2016
Biologiska institutionen, Lunds universitet (Less)
Please use this url to cite or link to this publication:
author
Sternäng, Märta
supervisor
organization
course
BIOY01 20161
year
type
M2 - Bachelor Degree
subject
language
English
id
8891571
date added to LUP
2016-09-13 11:40:54
date last changed
2016-09-13 11:40:54
@misc{8891571,
  author       = {Sternäng, Märta},
  language     = {eng},
  note         = {Student Paper},
  title        = {Density distributions of juvenile fish in South Australia - Focusing on the influence of coastal habtitats on climate change-induced range shifts in fish},
  year         = {2016},
}