Status, the recovery factor would be 0.5. As noted 
above, no recovery factor would be used for popula- 
tions determined to be at optimum sustainable levels. 
The potential biological removal levels would be 
calculated by multiplying the product of the estimated 
minimum population size and the per capita rate of 
increase by the recovery factor. When reliable 
estimates of a stock’s per capita rate of increase at its 
maximum net productivity level are not available, 
default values would be used. As in the initial draft 
regime, default values of Ryyp, would be 6 percent 
for pinnipeds and sea otters and 2 percent for ceta- 
ceans and manatees. 
Potential biological removal levels for endangered, 
threatened, and depleted stocks may be further adjust- 
ed to ensure that recovery occurs without significant 
delay. Among other things, such adjustments could 
be made to conform to conservation or recovery plans 
for these species. While the Commission had recom- 
mended that no taking from an endangered, threat- 
ened, or depleted stock be allowed until a conserva- 
tion or recovery plan was in place, the Service 
thought its proposal sufficiently conservative to make 
such a requirement unnecessary. Under the Service’s 
proposed regime, takes from such stocks could be al- 
lowed on an interim basis for a 240-day period, 
during which time conservation or recovery plans 
would be developed. 
As noted above, potential biological removal levels 
would be calculated using the best available estimates 
of minimum stock size. To gather this and other 
information necessary to calculate potential biological 
removal levels and to make status of stock determina- 
tions, the Service proposes to build on its stock 
assessment and research program. Priority would be 
given to those species listed as endangered or threat- 
ened and to declining populations. The Service would 
prepare draft stock assessment reports to be reviewed 
by independent peer review panels comprised of 
scientists from the Marine Mammal Commission, 
other Federal and state agencies, and academia. 
Representatives of the fishing industry and the envi- 
ronmental community would participate on the review 
panels in an advisory capacity. After review by the 
scientific panels, the stock assessment reports would 
| 
Chapter IV — Marine Mammal-Fisheries Interactions 
be revised and made available for public review and 
comment before final adoption. 
Marine mammal stocks would be classified accord- 
ing to their status and the level of take relative to the 
calculated potential biological removal level. A stock 
would classified as a Class Alpha (a) stock if it is 
endangered, threatened, or depleted, or if the total 
estimated removals from the stock, from all sources, 
equals or exceeds the estimated potential biological 
removal level. All other marine mammal stocks 
would be classified as Class Beta (8) stocks. 
The Service’s proposal identifies 64 marine mam- 
mal stocks that are or may be subject to taking inci- 
dental to commercial fishing. Of these, 12 are 
considered to be Class a stocks by virtue of being 
listed as endangered or threatened or designated as 
depleted. Preliminary data for 14 other stocks indi- 
cate that they would likely be Class a stocks because 
estimated removals would exceed the calculated 
potential biological removal levels. An additional 12 
stocks would preliminarily be considered to be a 
stocks because there are insufficient data to make 
abundance estimates and to calculate potential biologi- 
cal removal levels. The remaining 26 stocks would 
be Class B stocks. 
Each fishery would be classified on the basis of its 
marine mammal interactions. Fisheries that do not 
take marine mammals would not be included within 
the proposed regime. 
A fishery having a significant impact on a Class a 
stock would be designated as a Category I fishery. A 
fishery which takes Class a marine mammals, but 
which does not have a significant impact on any Class 
a stock would be designated as a Category II fishery. 
Category II would also include those fisheries having 
significant impacts on Class 6 marine mammal stocks. 
Fisheries taking only Class 6 marine mammals at 
insignificant levels would be classified as Category III 
fisheries. Under the Service’s proposal, the level of 
incidental take would be considered significant if it 
increases the time needed for recovery of an a stock 
by 10 percent or more or if removals exceed 0.5 
percent of the minimum abundance estimate for a B 
stock. These criteria for determining whether the 
effects of incidental taking are significant are consis- 
