Habitat Suitability of the Round Goby (Neogobius melanostomus) and the Effect of Marine Protected Areas on its Distribution in the Baltic Sea

Abstract

Invasive species are one of the leading causes of biodiversity loss worldwide, and effective management of protected areas is one of the primary ways in which conservationists try to limit their impacts and dispersal. The round goby (Neogobius melanostomus) is a problematic invasive species in the Baltic Sea, along with other brackish waters, lakes, and rivers in Europe and North America, having been transported from its native range in the Ponto-Caspian region via ballast water of ships. It is a highly adaptable species, tolerant of a wide range of salinities and temperatures, and has been highly successful in its colonisation of the Baltic Sea since its arrival, approximately 25 years ago. Here, the habitat suitability of the Baltic Sea is modelled using Maxent, a commonly-used species distribution modelling (SDM) technique, investigating the effect of various biotic and abiotic factors on the distribution of the round goby. Depth, wave exposure, and sea surface temperature were highly important when determining habitat suitability, as were salinity and shipping, to a lesser degree. Round gobies in the Baltic Sea prefer shallow, warmer waters, sheltered from significant wave action. They are more likely to be found near areas of intense shipping, likely due to this being their primary method of long-distance dispersal. Protected areas had an unexpectedly complex effect, hindering round gobies in highly suitable areas, but proving to be more vulnerable than unprotected areas in suboptimal habitats. Further studies investigating the effect of specific protected area management strategies, rather than a simple comparison of protected and non-protected areas, may reveal more detailed ways in which the spread of the round goby can be limited.

Popular Abstract

Where are the gobies and can they be stopped?

Background information

Invasive species are one of the greatest problems in conservation today. An invasive species is one that has been introduced to an area (often through human activity) and has become problematic, disrupting native species. Knowledge regarding where an invasive species can be found and the environmental factors that govern their distribution is important when attempting to limit their spread. Designated protected areas are one of the primary ways in which we attempt to limit invasive species – by working to protect and conserve important habitats and native species, we reduce the risk of new species becoming invasive in that area.

In my thesis, I investigated the round goby, a hugely problematic invasive fish species. Within the last 30 years, it has spread from the Black Sea across European rivers, into the Baltic Sea, and even across the Atlantic to the North American Great Lakes. This is due to human shipping activity – ships departing from the goby’s native habitat pick up ballast water (to adjust stability and buoyancy) along with goby juveniles, and then transport them to other locations, where they then release the water, along with the gobies. In many invaded areas, it has become overwhelmingly dominant, to the detriment of local species.


This study

My aim here was to investigate what areas in the Baltic Sea were preferred by gobies. This allows us to predict where we are likely to find them which helps policymakers to take action and try and reduce the impacts of the round goby. I also wanted to look at whether established protected areas in the Baltic Sea were having any notable effect on the round goby’s distribution – if protected areas aren’t working to limit them, then we need to investigate other management strategies.

During my analysis, I found that round gobies prefer warm, shallow areas, sheltered from waves. They are also more likely to be found in less salty areas with lots of vegetation, near shipping lanes, and prefer areas that have complex rocky sea beds, rather than sandy or muddy areas. This makes the round goby likely to be found along much of the coastal areas of the southern Baltic, particularly within archipelagos. However, due to their adaptability, any area in the Baltic with sufficient shipping is likely to suffer an invasion, although the population may not be capable of sustaining itself in areas that are more exposed, colder, and saltier.

The effect of protected areas was not straightforward. In areas with highly suitable habitats (shallow, sheltered, etc.), protected areas did indeed reduce the probability of finding gobies. However, in areas with less suitable habitats, protected areas were actually more at risk to goby invasion. This inverted relationship is likely because these less suitable areas were also not ideal for native species, therefore there were fewer competitors to resist the invasion in these locations. This suggests that maybe we should be more discerning with regards to placement of protected areas.


Master’s Degree Project in Biology 30 credits 2018
Department of Biology, Lund University

Advisors: Anders Persson, Aquatic Ecology, Lund University
Ullrika Sahlin, Centre for Environmental and Climate Research, Lund University

• author: Holmes, Mark
• supervisor: Anders Persson
• organization: Degree Projects in Biology
• course: BIOM02 20181
• year: 2018
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• language: English
• id: 8952195
• date added to LUP: 2018-06-21 12:17:14
• date last changed: 2018-06-21 12:17:14