Halacarid mites (Acari: Halacaridae) associated with a North Atlantic subtidal population of the kelp Laminaria ochroleuca

Abstract

We characterised the mite fauna associated with a subtidal population of Laminaria ochroleuca in the Cantabrian Sea during a 4-year study. We found 2780 individuals belonging to 35 species. The mite assemblage comprised both north Atlantic and Mediterranean species, as usually reported from the Lusitanian region. The most abundant and diverse subfamily was Copidognathinae, followed by Halacarinae and Lohmannellinae. The greatest abundance of mites was detected on kelp holdfasts, not only strictly phytal mites were found but also interstitial mites or those associated with other macrofauna. Such a distribution could be explained by the high diversity and heterogeneity of microhabitats provided by holdfasts. Mite abundance fluctuated during the 4 years of the study. However, the lowest abundance was detected during the last year of sampling. During that year, the studied algal population suffered a severe decay leaving only degenerating holdfasts attached to the substrate, which could explain the decrease in mite numbers.

Keywords:

• Acari
• Halacaridae
• macroalgae
• phytal fauna
• Lusitanian region

Acknowledgements

We are indebted to Dr Ilse Bartsch for her help in mite identifications and critical reading of the manuscript, and to Dr Pugh, who improved the style and discussion of the manuscript. We are also thankful to the staff of ACEM for their help during sampling and Dr Manuel Maldonado for helpful comments and fruitful discussion. This study was funded by two grants from the Marcelino Botín Foundation and one from the Spanish government (BOS 2000-0568).