Half centuries from Caleb Jewell and Mitchell Owen have kept Tasmania's first innings on track in their Sheffield Shield match against Western Australia.Tasmania, who lost to WA just a fortnight ago by six wickets in a Shield final rematch in Perth, ended day one 7-302 at Bellerive Oval.A run-a-ball 83 from No.7 Owen helped lift the hosts from a precarious 4-153.The Shield champions travelled to Hobart on top of the standings, but missing numerous key personnel.Among the absentees were opener Cameron Bancroft, Cooper Connolly and rising spinner Corey Rocchiccioli on Australia A duty; Aaron Hardie and Josh Inglis preparing for upcoming one-day internationals, as well as Mitch Marsh (paternity leave) and Charlie Stobo (omitted).Tasmania lined up without key middle-order batter Beau Webster who led the Tigers' run-scoring tally last season, while the bowling line-up was boosted by the return of Gabe Bell and Lawrence Neil-Smith.The home side survived the opening session without loss after being sent in to bat by opposition skipper Ashton Turner.The Tigers posted a century stand before rookie medium-pacer Brody Couch had Jake Weatherald caught down the leg side for 49.The ever-reliable Joel Paris then did the damage midway through the second session as Tasmania lost 3-18.Jewell was trapped lbw for 61 after surviving an earlier let-off, before Charlie Wakim (24) and captain Jordan Silk (10) were both soon sent back to the pavillion.Owen fell in the final hour having struck 13 boundaries and two sixes in a career-best knock, only for Paris to end the dangerous innings.Brad Hope was then dismissed for 25 off Cameron Gannon having shared a 102-run stand with Owen.Paris ended the day with 4-38 from 21 impressive overs with Gannon (2-66) and Couch (1-93) the other wicket-takers.