NMFS has received a request from the U.S. Navy (Navy) for an Incidental Harassment Authorization (IHA) to take marine mammals, by harassment, incidental to Civilian Port defense activities within and near the Ports of Los Angeles and Long Beach from October through November 2015. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an IHA to the Navy to incidentally take, by Level B harassment only, marine mammals during the specified activity
NMFS uses “functional hearing groups” to assess marine mammal effects for this proposed IHA. According to NMFS:
“Southall et al. (2007) designated ‘‘functional hearing groups’’ for marine mammals based on available behavioral data; audiograms derived from auditory evoked potentials; anatomical modeling; and other data. Southall et al. (2007) also estimated the lower and upper frequencies of functional hearing for each group. However, animals are less sensitive to sounds at the outer edges of their functional hearing range and are more sensitive to a range of frequencies within the middle of their functional hearing range. Note that direct measurements of hearing sensitivity do not exist for all species of marine mammals, including low-frequency cetaceans. The functional hearing groups and the associated frequencies developed by Southall et al. (2007) were revised by Finneran and Jenkins (2012) and have been further modified by NOAA. Table 2 provides a summary of sound production and general hearing capabilities for marine mammal species (note that values in this table are not meant to reflect absolute possible maximum ranges, rather they represent the best known ranges of each functional hearing group). For purposes of the analysis in this document, marine mammals are arranged into the following functional hearing groups based on their generalized hearing sensitivities….”
NMFS’ Table 2 follows:
“TABLE 2—MARINE MAMMAL FUNCTIONAL HEARING GROUPS
Functional hearing group Functional hearing range *
Low-frequency (LF) cetaceans (baleen whales) ……………………………………………………………………….. 7 Hz to 25 kHz.
Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) …….. 150 Hz to 160 kHz.
High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, cephalorhynchid,
Lagenorhynchus cruciger & L. australis).
200 Hz to 180 kHz.
Phocid pinnipeds (underwater) (true seals) ……………………………………………………………………………… 75 Hz to 100 kHz.
Otariid pinnipeds (underwater) (sea lions and fur seals) ……………………………………………………………. 100 Hz to 48 kHz.
Adapted and derived from Southall et al. (2007).
* Represents frequency band of hearing for entire group as a composite (i.e., all species within the group), where individual species’ hearing ranges are typically not as broad. Functional hearing is defined as the range of frequencies a group hears without incorporating non-acoustic mechanisms (Wartzok and Ketten, 1999). This is ∼ 60 to ∼ 70 dB above best hearing sensitivity (Southall et al., 2007) for all functional hearing groups except LF cetaceans, where no direct measurements on hearing are available. For LF cetaceans, the lower range is based on recommendations from Southall et al., 2007 and the upper range is based on information on inner ear anatomy and vocalizations.”
Comments and information on this IHA must be received by NMFS no later than October 5, 2015.
Click here for NMFS’ Federal register notice of this proposed IHA.