Paternal care behaviour of sand gobies is determined by habitat related nest structure

Summary This study examines the effects of habitat-dependent nest structure on male parental behaviour in a small marine fish, the sand goby (Pomatoschistus minutus). In the northern Baltic, the sand goby breeds in two different habitats: on soft sand bottoms and on rocky beaches. We compared in laboratory conditions the behaviour of nest-guarding males occupying either a typical sand or rock habitat nest. We found that males with a rock habitat nest fanned their eggs considerably less and with shorter bouts than males in the sand habitat treatment. Hence, our study shows that nest structure can be an important factor determining parental care behaviour. The differences in nest structure may result in divergent selection pressures on male sand gobies occupying the two habitats.