As you've read, Marine Biologist is not on the new Skilled Occupations List (SOL) which will take effect from 1 July, so it is no longer an eligible occupation for independent or relative sponsored migration.
http://www.immi.gov.au/skilled/general-skilled-migration/pdf/new-list-of-occupations.pdf
It is however still on the Employer Nomination Scheme Occupation List (ENSOL) so is eligible for employer sponsored migration. A permanent visa (PR) from the outset is only available if the applicant has 3 years of professional, full time work experience in the profession and if the sponsoring employer is prepared to offer a 3 year contract and sponsorship for a permanent visa. Otherwise, it is only eligible for a temporary subclass 457 visa which can however lead to PR after 2 years employment on a 457 (including at least 1 year with the sponsor) if the employer is willing to sponsor the employee for a permanent visa.
http://www.immi.gov.au/allforms/pdf/1121i.pdf This is now only the ENSOL - the list has not been updated since the new SOL was released on 17 May.
http://www.immi.gov.au/skilled/skilled-workers/visa-options.htm Employer sponsored visas
One of my daughters is a Marine Biologist in Queensland and the comments scat has made about the required qualifications and experience are correct. Some Masters graduates will find work but an international would be unlikely to be able to find employer sponsorship. At the very least, a new Masters graduate would need to spend 18 months on a temporary Graduate visa to enable them to get involved in projects that may lead to sponsorship - an outstanding (and lucky) candidate may be successful but it would be a long shot. You are only eligible to apply for a Graduate visa after 2 academic years (92 weeks) of Australian studies leading to qualifications in your nominated occupation.
http://www.immi.gov.au/skilled/general-skilled-migration/485/ Graduate visa
An outside chance (after a Graduate visa to gain work experience) is a state government sponsored visa but none of the states has yet released a State Migration Plan (SMP) and until they are available (perhaps in July?), it's not possible to know what occupations will be included. Until they recently suspended acceptance of nominations, South Australia had been offering provisional regional sponsorship to MBs but there is no way of knowing if the profession will be on their (or any other) SMP or what the conditions will be if it is included. SMPs are a new concept and not much information is currently available about how they will work.