MARINE MAMMAL COMMISSION — Annual Report for 1992 
implement the regime, and a proposed schedule for 
implementation. 
The National Marine Fisheries Service’s initial 
draft regime was published and distributed for com- 
ment on 24 May 1991. In most respects, the Ser- 
vice’s initial proposal closely followed the guidelines 
recommended by the Commission. The primary 
difference was the addition of a general procedure for 
estimating the number of marine mammals that could 
be allowed to be removed from a population without 
causing it to be reduced or maintained below its 
maximum net productivity level — the lower limit of 
the optimum sustainable population range. This 
number was termed the “allowable biological remov- 
al” level. The total annual removal of animals from 
a population from all sources could not exceed the 
estimated allowable biological removal level. Allow- 
able biological removal levels would be calculated for 
each marine mammal stock by multiplying the estimat- 
ed minimum abundance of the stock by the best 
estimate of the stock’s maximum annual net productiv- 
ity rate and by a recovery factor, which would vary 
depending on the status of the stock relative to its 
carrying capacity. Default values for maximum net 
productivity rates of six percent for pinnipeds and sea 
otters and two percent for cetaceans and manatees 
would be used when specific information on net 
productivity rates is unavailable. Recovery factors 
would depend upon a qualitative estimate of a stock’s 
status and would be 0.9 for stocks believed to be 
above two-thirds of their carrying capacity level (i.e., 
for stocks within their optimum sustainable population 
range), 0.5 for stocks between one-third and two- 
thirds of carrying capacity (moderately depleted 
stocks), and 0.1 for stocks below one-third of carrying 
capacity (severely depleted stocks) or for which 
information necessary to make a status determination 
is unavailable. 
The allowable biological removal level calculated 
for each stock would be allocated annually by the 
Service among the various user groups. The Service 
proposed to give priority to those takes that it could 
not control, such as subsistence harvests of non- 
depleted marine mammals, collisions with ships, and 
incidental takes by foreign fisheries outside the U.S. 
Exclusive Economic Zone. All or part of the remain- 
ing allowable biological removal would be allocated to 
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“controllable” activities such as commercial fishing, 
public display, and scientific research. Allocations 
would be based on an assessment of need, economic 
impacts, historic take levels, and the ability of the 
user group to reduce its level of take. 
By letter of 23 September 1991 the Marine Mam- 
mal Commission provided the Service detailed com- 
ments on the initial draft regime. The Commission 
noted that most parts of the draft regime were concep- 
tually sound, but that in some cases, the regime was 
not explained in sufficient detail to allow critical 
evaluation. In this regard, the Commission noted that 
placing stocks in the three categories for applying 
recovery factors constituted de facto status of stocks 
determinations. The Commission therefore recom- 
mended that the Service base these determinations on 
clearly articulated criteria and use procedures that 
afford an opportunity for full scrutiny of the evidence 
before the agency, provide for independent review of 
the data, and require a complete explanation of the 
rationale for the determinations made. 
The Commission also noted that it was not clear 
how the draft regime would deal with situations in 
which marine mammal carrying capacity has been 
reduced by overharvesting of prey species or other 
types of habitat degradation or destruction caused by 
commercial fisheries, coastal development, offshore 
oil and gas development, or other activities. In 
addition, while the Service’s draft regime addressed 
mortalities and other removals of animals from wild 
populations, it did not indicate how noise disturbance 
and other forms of harassment, which also may result 
in decreased survival and productivity, would be 
considered. 
The Commission also noted that the proposed 
formula for calculating allowable biological removal 
levels would not always yield conservative estimates 
as asserted. For example, the Service proposed to 
calculate the allowable biological removal level using 
the “best estimate of the stock’s net production rate at 
the population level where net productivity is maxi- 
mized” even when the population is known to be 
declining or the actual growth rate is known to be less 
than the estimated maximum growth rate and when 
there is uncertainty as to whether the decline or 
reduced growth rate is due to factors other than inci- 
