Parthenogenesis is an asexual reproduction wherein offspring develops from unfertilized eggs. Usually, female offspring are developed from unfertilized eggs.
Parthenogenesis is only possible in favorable environmental conditions, if conditions are not stable, then, sexual mode of reproduction is done.
If the only method for shark reproduction is through parthenogenesis then it can be harmful to the survival of the species because shark cannot reproduce unless the environmental condition is favorable. For example, environmental conditions have been unfavorable for a long time, then those sharks that are existing may slowly die without reproducing the next generation of their species, decreasing their number until the species die out.