Increasing attention has been given marine benthic macrofauna due to its importance in marine ecosystems and for its value as bioindicator of environmental changes. One of the most abundant groups among benthic macrofauna are echinoderms which often hold keystone positions in the ecosystems and have proven to be good bioindicators. The aim of this study was to inventory echinoderms and analyze whether species diversity has change over time in Gullmarsfjorden, a fjord with limited water exchange and hence highly sensitive to environmental fluctuations. Also, what may have caused any changes and what potential effects can it have on ecosystems in the fjord, and which species may be valuable as bioindicators. The results show that species diversity of echinoderms has decreased significantly since the early 1900s and the main reduction have occured among species living on/in soft or sandy bottoms. Many of the lost echinoderms species are essential bioturbators and thus important to marine ecosystems. However, Echinocyamus pennatifidum, a sea urchin which is a valuable bioturbator may have established in the fjord during the last century judging from this study. Species like Asterias rubens and Psammechinus miliaris, which are common in the fjord, have also proved to be valuable bioindicators for abiotic changes such as increased CO2-levels and pollution of heavy metals and PCB.

Prehistoric remains show that people have lived in the Munkedal area since the Stone Age. The early industrialization was favored by the rich natural resources, especially the proximity to forests and water. The fjord opened up the area to the world and provided good opportunities for export. These conditions attracted wealthy merchants and traders who boosted the area's economic development. The affluent built lavish manor houses, which led to a concentration of manor house complexes around the inner part of Gullmarsfjorden. The manor houses have origins from the 1700-1900th century and are more or less preserved today. Their strong connection to the area's history permeates the entire study. The result shows that the manor houses possess high cultural-historical values and should be treated accordingly. In the detailed development plan, all manor houses should have legally binding protection against alteration and be marked with the letter "q". With inadequate knowledge combined with insufficient legal protection, the manor houses and with them, a large part of the area's history, are at risk of being lost. Today, several of them are well preserved, but some inappropriate measures have been taken and three have been demolished. Very little of the gardens, park environments, and other farm buildings are preserved.