We're half-way through the surveys! So far, we have found 128 otter spraints in the 19 locations surveyed (see attached maps). Forty-two out of the 128 were fresh spraints left by the otters the previous night. These fresh spraints will be genotyped using a novel multiplex panel of 11 microsatellite markers to identify otter individuals which will be also sexed by typing the sex-chromosome-related gene ZFX/ZFY, as suggested by a Spanish research team (Vergara et al., 2014).
Although in the two spring surveys already carried out, we have detected spraints in the gravel quarry lagoon system, in the ditch, in the irrigation channel and in the Duero River, the marking intensity (number of spraints/100 meters) vary considerably across the different water body types (see attached figure). Interestingly, the highest spraint marking intensity is found in the Middle Lagoon of the gravel quarry. This marking intensity variable will help determining specific otter habitat requirements in the area, which will in turn inform the design of one of the outcomes of the project; a guide for the management of aquatic mammals and practical measures for the ecological restoration of gravel quarries.
What new discoveries are lying ahead in the summer surveys? You will have to wait until following posts to know it.