Halve the salmon lengthwise and cut crosswise into 12 pieces.
Mix the salmon pieces with the pesto and lemon juice, cover and set aside briefly.
Cook the lasagne sheets in boiling, salted water until just al dente, rinse under cold water, drain and lay out on a damp cloth.
Combine the Ricotta and cheese, season. Divide the Ricotta filling over the lasagne sheets, leaving a margin of approx. 1 cm free along each of the short ends.
Place the fish pieces on top, roll up the lasagne sheets and transfer to the prepared oven dish.
Combine the cream, pesto and cheese, divide over the cannelloni then scatter with the pine kernels.
Gratinate for approx. 20 mins. in the centre of an oven preheated to 220°C.
Remove, grate over the lemon zest and scatter with rocket.