Líffræðifélag Íslands
Líffræðiráðstefnan 2015
Erindi/veggspjald / Talk/poster E70
Óskar Sindri Gíslason (1,2,3), Jónas Páll Jónasson (4), Snæbjörn Pálsson (3), Jörundur Svavarsson (3), Halldór Pálmar Halldórsson (2)
1. Rannsóknasetur Háskóla Íslands á Suðurnesjum, 2. Líf-og umhverfisvísindadeild Háskóla Íslands, 3. Náttúrustofa Suðvesturlands, 4. Hafrannsóknastofnun
Kynnir / Presenter: Óskar Sindri Gíslason
Tengiliður / Corresponding author: Óskar Sindri Gíslason (sindri@natturustofa.is)
The Atlantic rock crab (Cancer irroratus) has recently colonized Icelandic waters and is spreading rapidly along the coastline. The species is reproducing successfully in Iceland and there are strong indications that the rock crab is becoming common in soft bottom coastal habitats in SW-Iceland. To be able to evaluate the impact of such non-indigenous species on the ecosystem, density estimates are required. In the years 2011 to 2014 a mark-recapture study was carried out on rock crabs in a small inlet in the fjord Kollafjörður, southwestern Iceland. In total 6,475 rock crabs were captured and of them 4,670 were tagged with sequentially numbered T-bar anchor tags. Of the crabs tagged, 155 were recaptured over the four years (3.3 %), 34 had moulted and one of them presumably two times over the four year period. The size range of recaptured crabs was 7.3 to 12.8 cm carapace width (CW) and the growth increment per moult ranged from 1.2 to 2.6 cm, with an average of 2 cm. Based on the mark-recapture analysis, the population at the study area in Kollafjörður was estimated to be about 107,000 individuals, with the density of about 0.5 crabs per square meter. This is among the highest densities documented for the species.