In 2003, due to fears that the charter sector was growing at an alarming rate, regulators led by commercial fishing interests established a Guideline Harvest Level for guided anglers. This essentially divided the recreational fishery into guided and unguided anglers. Ever since then, charter clients (guided anglers) have been managed separately.
While it is true the larger halibut are all females 16 - 25 year olds, the most fertile and abundant population of female halibut are between the ages of 12 - 14 years old (approx. 15# - 30#). This is the portion of the stock that the majority of stock growth comes from. This is why it is important to follow these year classes as they move through the fishery.
There has been past discussions regarding the theory of "fishery induced evolution", that is if you harvest all the large halibut out of the fishery, you would be left with only slow growing halibut. However, biologist argue that a large halibut has reproduced in the fishery all its life and has left its gene signature in the fishery. Also, evolutionary changes occur over many generations and we have seen a reduced size at age of halibut in the span of just thirty to forty years, not supporting the theory of "fishery induced evolution".
Chalky halibut are fish that, when cut open, have a stiff, chalk-textured flesh as opposed to the normal pale and tender flesh. Chalky meat is not dangerous to humans but is not desirable and thus costs the fishermen at the dockChalky halibut is not a new phenomenon; fishermen and researchers have been seeing it for decades. IPHC research from the 1960s and 1990s connect the prevalence of chalky flesh with the buildup of lactic acid in the fish and lowered pH in the fish after death.
Female halibut are mature and spawn at around age 11 - 12 and are approximately 36" - 38" in length (20 - 25 lbs. in the round).