• Overview
  • Objectives
  • Costs to Consider
  • Site Conditions

Many sea urchin populations in the Adriatic have undergone significant population increases due to a reduction in predation pressure. Urchins are prolific herbivores that can clear large areas of macroalgae relatively quickly, forming what are known as urchin barrens. Macroalgae dominates many shallow areas in the region, forming the foundation of the ecosystems, and so an increase in dominance of urchin barrens can severely alter the habitat, removing the food, structure and shelter macroalgae naturally provides to other animals. This project aims to investigate the ecological impacts of these urchin barrens through a range of in water surveys completed via SCUBA diving. First, urchin barrens will be mapped around the coast of Silba island to give a broad estimate of their abundance and also identify areas of high and low urchin barren density. Barrens will then be analysed in detail using quadrats and compared to nearby areas of healthy macroalgae, to determine the impacts of urchins on the benthic community. Surveys of the macroinvertebrate community will then be carried out using belt transects, to identify impacts of urchin barrens on their abundance and diversity. Finally, fish surveys will be completed using Underwater Visual Census (UVC) to determine whether the coverage of urchin barrens has any measurable impact on the abundance and diversity of adults or juvenile fish species.

Extended Dissertation Summary

If you would like to do a dissertation or thesis with us but your university hasn’t started dissertation planning or the project selection process, that’s no problem. You can cancel your expedition with zero cancellation charges up until the 15th of April of if you provide documentation from your university saying that they won’t support completing a dissertation project with us.

Croatia Terrestrial Research Objectives

Krka National Park

The Krka Valley runs from the Dinaric mountains bordering Bosnia to the Adriatic and is only 77km in length. However, since the river runs through limestone there are some spectacular gorges and this is one of the most scenic river valleys in Europe. It is also important from a biodiversity viewpoint containing nine Croatian and three Krka endemic fish species and spectacular cave systems containing a number of potentially new species to science. Opwall together with Biota (a Croatian biodiversity research organisation) has built a research centre in the central part of the Krka valley with easy access to the whole park. The centre is based in a restored house and grounds within 100m of the park boundary and has access to all the habitats throughout the park and surrounding countryside. The National Park Authority have requested we perform baseline surveys to increase the known inventory for the Park, as well as collect long-term monitoring data to answer a series of their management questions.

Tourist visits to Krka National Park are heavily concentrated towards the lower stretches of the river and very few people visit the central and northern parts of the valley. The Biota/Opwall research centre is based within a rural community that has suffered from significant depopulation and land abandonment in recent years. The centre is designed to give benefits to the local community from the visits (e.g. provision of employment etc). Whilst the main research effort each year from this centre comes through the Opwall programme, the centre will remain open year round in an attempt to attract some of the many visitors to the Croatian coast further inland, increasing revenue for the Park and local communities.

  • Opwall fee.
  • Cost of international flights into and out of Split or Zadar.
  • Cost of internal travel to and from the start and end point of the expedition, plus any hotels you might require. Standard package costs around £110 or $143.
  • Extra nights’ accommodation in Split or Zadar costs £110 or $143 (breakfast included).
  • Dive equipment rental – £60 or $75 per week for a full dive kit. If you only wish to snorkel and want to hire snorkel equipment, the cost is £35 or $25 per week. Please note that wetsuits cannot be provided – you should bring your own.
  • Park entrance fees – £25 or $33.
  • PADI manual and PIC card (if you are completing your Open Water qualification) – £69 or $89 approx.
  • Vaccinations and prophylactic medicines – cost can vary depending on your healthcare provider.
  • All prices in GBP or USD unless specified.
  • Standard travel insurance – cost can vary, for 2 weeks it can range anywhere from £40-80 or $40-150.

Most of our volunteers fundraise for their expedition costs. Find out more.

Croatia is hot during this time of the year! In both Krka and Silba the daytime temperature rarely drops below 30 degrees and can reach 40 degrees.

Fitness level required
Moderate. Whilst there are not many steep hikes in the forest, the hikes are still quite long and the temperature can make them tiring.

Creature comforts
At Krka you will either be staying in dormitories or in shaded tents with shared western style bathrooms and toilets. There is also some limited phone signal in Krka (but not reliable for a data connection).


  • Croatia
  • Silba

Want to get involved with this project?


Want to get involved with this project?

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