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________________________________

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________________________________________________________

Cover illustration courtesy of Pieter Folkens/Alaska Whale Foundation © 2002


iii

EXECUTIVE SUMMARY

In 2001, field studies of the endangered Hawaiian monk seal (Monachus

schauinslandi) were conducted at all of its main reproductive sites in the Northwestern

Hawaiian Islands. These studies provide information necessary to identify and mitigate

factors impeding the species recovery by evaluating (1) the status and trends of monk seal

subpopulations; (2) natural history traits such as survival, reproduction, growth, behavior,

and feeding habits; and (3) the success of various activities designed to facilitate

population growth. 

Results of these studies are best described on a site-by-site basis, and the

information presented in this document is organized accordingly. Site-specific data

pooled for all sites, however, provide useful indices of the status and trends of the species

as a whole, including the total number of pups at all main reproductive sites, the total of

the site-specific mean beach counts, and the size composition of the seals observed during

the counts (Fig. 1).

Since 1983, the number of pups born at the main reproductive sites has been

highly variable, and the variability has been largely determined by the number born at

French Frigate Shoals (FFS) (Fig. 1a), the largest subpopulation. In 2001, 178 pups were

counted at these sites, 63 of which were born at FFS. Mean beach counts, excluding pups,

from the main reproductive sites totaled 351.8 seals. Counts remained essentially

unchanged from 1993 to 2000, but declined in 2001 (Fig. 1b). 

From the mid-1980s to the mid-1990s, adults and pups comprised a growing

portion of the animals counted while juveniles and subadults declined (Fig. 1c) and in

2001, the composition of the counts again was dominated by adults and pups. This

composition bodes poorly for reproduction in the near future if older adult females are not

replaced by young females reaching reproductive age. High mortality of immature seals

appears to have led to the shift in composition, particularly at FFS.

Under provisions of the Marine Mammal Protection Act of 1972, the Working

Group on Marine Mammal Unusual Mortality Events (UME) determined that a UME

involving juvenile Hawaiian monk seals had occurred at Laysan Island in the spring of

2001. Declaration of the UME was based primarily on the deaths of 4 juvenile seals that

occurred over a 1-week period on Laysan Island, but investigation of the UME included

other major subpopulations to assess possible range-wide impacts. Objectives of the

UME response team were to necropsy dead seals, visually evaluate the health of seals

observed, and sample clinically abnormal and clinically normal seals from the 1- and 2-

year-old cohorts (Yochem et al., 2003).

During 2001, four management activities were conducted by the Marine Mammal

Research Program (Pacific Islands Fisheries Science Center, National Marine Fisheries

Service) and cooperating scientists to enhance recovery of the species. First, debris
iv

capable of entangling seals was removed from all study sites, and 8 seals were

disentangled by field biologists. Second, researchers monitored beaches on Midway Atoll

for disturbance and sought to mitigate human impacts through education. Third,

researchers translocated weaned pups between islets within FFS to decrease their risk of

shark predation. And fourth, 5 Galapagos sharks were removed after exhibiting predatory

behavior toward monk seal pups at FFS.

This document describes these and other field studies conducted during 2001 and

provides complete, standardized, and timely summaries of the research activities and

findings at each study site. The ready availability of such information is essential for

ongoing efforts to stop the decline of this species and enhance its recovery.
v

Fig. 1. Demographic trends of the Hawaiian monk seal, based on the main reproductive

sites (excluding Midway Atoll). A) Number of pups born (minimum). B) Total of mean

beach counts, excluding pups, with 1 standard deviation. C) Percentage of counts

comprised of adults, subadults, juveniles, and pups.

vii

CONTENTS

Page

CHAPTER 1. GENERAL INTRODUCTION ................................. 1

MATERIALS AND METHODS ........................................ 4

Censuses and Patrols .............................................. 4

Reproduction .................................................... 5

Factors Affecting Survival .......................................... 5

Individual Identification ............................................ 6

Measurements of Seals ............................................ 7

Collection of Samples ............................................. 7

CHAPTER 2. THE HAWAIIAN MONK SEAL ON

FRENCH FRIGATE SHOALS, 2001 ....................................... 9

RESEARCH ....................................................... 11

Censuses and Patrols ............................................. 11

Individual Identification ........................................... 12

Collection of Samples ............................................ 12

Special Studies .................................................. 12

Galapagos Shark Observations, Deterrence, and Culling from Trig Islet . . 12

Tagging of Tiger, Galapagos, and Gray Reef Sharks .................. 12

Translocation of Weaned Pups .................................. 13

Night Observations of Mother/Pup Pairs on Trig Islet ................ 13

Foraging Ecology, Health, and Disease ............................ 13

RESULTS ........................................................ 14

Subpopulation Abundance and Composition ........................... 14

Reproduction ................................................... 14

Interatoll Movement .............................................. 14

Factors Affecting Survival ......................................... 14

ACKNOWLEDGMENTS ............................................ 15

TABLES .......................................................... 17
(CONTENTS, continued)

Page

viii

CHAPTER 3. THE HAWAIIAN MONK SEAL ON

LAYSAN ISLAND, 2001 ............................................... 25

RESEARCH ....................................................... 27

Censuses and Patrols ............................................. 27

Individual Identification ........................................... 28

Collection of Samples ............................................ 28

Special Studies .................................................. 28

Health, Disease, and Foraging Ecology ............................ 28

RESULTS ........................................................ 29

Subpopulation Abundance and Composition ........................... 29

Reproduction ................................................... 29

Interatoll Movement .............................................. 29

Factors Affecting Survival ......................................... 30

ACKNOWLEDGMENTS ............................................ 30

TABLES .......................................................... 31

CHAPTER 4. THE HAWAIIAN MONK SEAL ON 

LISIANSKI ISLAND, 2001 .............................................. 39

RESEARCH ....................................................... 41

Censuses and Patrols ............................................. 41

Individual Identification ........................................... 41

Collection of Samples ............................................ 42

Special Studies .................................................. 42

Health and Disease ............................................ 42

RESULTS ........................................................ 42

Subpopulation Abundance and Composition ........................... 42

Reproduction ................................................... 43

Interatoll Movement .............................................. 43

Factors Affecting Survival ......................................... 43

ACKNOWLEDGMENTS ............................................ 43

TABLES .......................................................... 45
(CONTENTS, continued)

Page

ix

CHAPTER 5. THE HAWAIIAN MONK SEAL ON

PEARL AND HERMES REEF, 2001 ...................................... 53

RESEARCH ....................................................... 55

Censuses and Patrols ............................................. 55

Individual Identification ........................................... 55

Collection of Samples ............................................ 55

Special Studies .................................................. 56

Health and Disease ............................................ 56

Emergent Reef Surveys ........................................ 56

RESULTS ........................................................ 56

Subpopulation Abundance and Composition ........................... 56

Reproduction ................................................... 57

Interatoll Movement .............................................. 57

Factors Affecting Survival ......................................... 57

ACKNOWLEDGMENTS ............................................ 57

TABLES .......................................................... 59

CHAPTER 6. THE HAWAIIAN MONK SEAL ON

MIDWAY ATOLL, 2001 ............................................... 67

RESEARCH ....................................................... 69

Censuses and Patrols ............................................. 70

Individual Identification ........................................... 70

Collection of Samples ............................................. 70

Special Studies .................................................. 70

Foraging Ecology, Health, and Disease ............................ 70

Emergent Reef Surveys ........................................ 71

Noteworthy Events ............................................... 71

Beach Monitoring and Public Education ........................... 71

RESULTS ........................................................ 72

Subpopulation Abundance and Composition ........................... 72

Reproduction ................................................... 72

Interatoll Movement .............................................. 72

Factors Affecting Survival ......................................... 72

ACKNOWLEDGMENTS ............................................ 73

TABLES .......................................................... 75
(CONTENTS, continued)

Page

x

CHAPTER 7. THE HAWAIIAN MONK SEAL ON

KURE ATOLL, 2001 ................................................... 83

RESEARCH ....................................................... 85

Censuses and Patrols ............................................. 85

Individual Identification ........................................... 85

Collection of Samples ............................................ 86

Special Studies .................................................. 86

Foraging Ecology, Health, and Disease ............................ 86

Noteworthy Events ............................................... 86

Impacts of Paradise Queen II Grounding .......................... 86

RESULTS ........................................................ 87

Subpopulation Abundance and Composition ........................... 87

Reproduction ................................................... 87

Interatoll Movement .............................................. 87

Factors Affecting Survival ......................................... 87

ACKNOWLEDGMENTS ............................................ 88

TABLES .......................................................... 89

CHAPTER 8. THE HAWAIIAN MONK SEAL ON

NIHOA AND NECKER ISLANDS, GARDNER PINNACLES, 

AND MARO REEF, 2001 ............................................... 97

RESEARCH ....................................................... 99

Censuses and Patrols ............................................. 99

Individual Identification .......................................... 100

Collection of Samples ........................................... 100

RESULTS ....................................................... 100

Subpopulation Abundance and Composition .......................... 100

Reproduction .................................................. 101

Interatoll Movement .............................................. 101

Factors Affecting Survival ........................................ 101

ACKNOWLEDGMENTS ........................................... 101

REFERENCES ...................................................... 103

APPENDIXES ........................................................ 107

Appendix A.--Reports summarizing annual field research on the Hawaiian monk

seal by the National Marine Fisheries Service and collaborating scientists . . A-1

Appendix B.--Hawaiian monk seal census form and 2001 census form directions. B-1
CHAPTER 1. GENERAL INTRODUCTION
25 0 

3001::=~~---+---+----4-

u /Kure Atoll 

I,) 'r..-4--Midway Atoll 

to· ~~.. • Pearl and Hermes Reef 

/Lisianski 1. ~ /. 

(t _./ ..............Laysan 1. 


\.:) (.> 	 ,~ 

'i:'J ..........., lJ 


I,..) '.' 

Maro Reef"""'- ~ .,./\~) /French Frigate S

hi, 

Gardner PInnacles . ~ ,.!," 	 ,.t~Necker 1. 

'/M:) ... ~f'A n ........N 

f:}'" 

.. , : 

Nuhau 1. 

20° 

________________________________________~I I 

Northwestern Hawaiian Islands Ma

,::::::. 

Johnston Atoll 

15°N~I------+---~---r------~-------

175°W 1650 	

Fig. 1.1 The Hawaiian Archipelago. 
3

The endangered Hawaiian monk seal (Monachus schauinslandi) hauls out and

breeds in the Northwestern Hawaiian Islands (NWHI, Fig. 1.1). The National Marine

Fisheries Service (NMFS) is the lead agency responsible for the recovery of the Hawaiian

monk seal. Each year the NMFS Pacific Islands Fisheries Science Center, Marine

Mammal Research Program conducts studies at the main breeding sites to provide

information necessary to evaluate (1) the status and trends of the monk seal

subpopulations; (2) natural history traits such as survival, reproduction, growth, behavior,

and feeding habits; and (3) the success of various activities designed to facilitate

population growth.

The Marine Mammal Research Program began research on Hawaiian monk seals

at most major reproductive sites in the NWHI during 1980 (Lisianski Island), 1981

(Laysan Island and Kure Atoll), 1982 (French Frigate Shoals (FFS) and Pearl and Hermes

Reef), and 1983 (Midway Atoll). Nearly every year thereafter, field camps of several days

to 9 months were established to monitor and enhance the recovery of this species. 

Limited population monitoring has also been conducted at Nihoa and Necker Islands,

where subpopulations may be limited to a small number of animals by availability of

haulout area. Reports summarizing past NMFS research are listed in Appendix A.

During 2001, Hawaiian monk seal research activities included (1) conducting

beach counts (censuses); (2) tagging weaned pups and other seals for permanent

identification and retagging animals to maintain identification; (3) identifying other seals

by previously applied tags and by natural or applied markings; (4) monitoring

reproduction, survival, injuries, entanglements, interatoll movements, disappearances,

and deaths; (5) performing necropsies; (6) collecting scat and spew samples for food

habits analysis; (7) collecting skin punches and shed molt samples for a DNA tissue bank;

(8) collecting samples of placentas found with or from “aborted fetuses” or with deceased

perinatal pups for histological and bacteriological examination; (9) applying satellitelinked dive recorders to track animals at sea and to investigate diving behavior; (10)

screening health and collecting blubber biopsies for fatty acid analysis; (11) disentangling

seals; (12) inventorying and removing debris capable of entangling seals; and (13)

investigating the Unusual Mortality Event at Laysan Island and other major

subpopulations. Location-specific objectives and summaries of data collected during the

2001 field season are described in the following chapters. Much of the information

presented in this memorandum is incorporated into larger data sets for additional analysis

and publication elsewhere. Research was conducted under the authority of the following

permits: State of Hawaii Entry Permit SEPO 100102, USFWS Special Use Permit HWN01005, and NMFS Marine Mammal Permit 848-1335.
4

MATERIALS AND METHODS

Censuses and Patrols

The primary means of data collection were censuses and patrols. Censuses

consisted of timed standardized beach counts during which an entire island or atoll was

surveyed for seals on foot. Although data were collected on all seals, animals that were in

the water or dead were excluded from the beach count totals. Identified individuals were

counted only once if they were resighted during the survey. The resulting counts did not

reflect total subpopulation size but provided an index of subpopulation size for

comparison among years and locations. Data collected on each seal observed during

censuses included size class (ranging from pup, juvenile, subadult, and adult size as

described in Stone, 1984 and Appendix B); sex; location on the island; beach position

(indicating whether the seal was in the water or on land); body condition (a subjective

estimate; e.g., fat, medium, or thin); identification information (permanent or temporary

identification numbers and tag numbers); molting status (an estimate of the percentage

completed); and disturbance index (the extent that the observer disturbed the seal). 

Further data were collected if any of the following events occurred: (1) factors affecting

survival (e.g., entanglements, mobbings, or shark injuries), (2) animal handling, (3)

photography, and (4) documentation of tag condition (e.g., good or broken). In addition,

behavioral data (seal associations and interactions) were collected on Laysan and

Lisianski Islands. A sample census form and guidelines for its completion are included in

Appendix B. Censuses were conducted once at Nihoa Island, three times at Necker Island,

twice at Gardner Pinnacles, and every 4 to 7 days at all other locations, starting at 1300

Hawaii Standard Time when possible, using census methods and criteria outlined in

Johanos et al. (1987). Atoll-wide counts for locations with more than a single island

(French Frigate Shoals, Pearl and Hermes Reef, Midway Atoll, and Kure Atoll) were

completed within 2 days. The perimeter of each study area was divided into sectors to

facilitate the analysis of data and detection of demographic trends in different geographic

areas. Census methods specific to each location are detailed in the following chapters.

Patrols consisted of untimed surveys of an entire island perimeter on foot. 

Information collected during patrols was similar to that collected during censuses. 

Because patrols were not timed, observers concentrated on documenting adult and

subadult behavior, identifying and marking individuals, and collecting scat and spew

samples. Island-specific standardized patrols were conducted at some locations and are

described in the following chapters. 

During all observation periods (i.e., censuses, patrols, and incidental sightings),

observers attempted to minimize seal disturbance by walking above the beach crest and

using vegetation as a visual barrier. On census days, activities that could disturb the

animals and bias the count were not conducted until after the count was completed. 

Additionally, the following were recorded whenever observed: (1) births, pup exchanges,

and weanings; (2) mating activities, adult male aggression, and post-mobbing
5

aggregations (defined below); (3) entanglements in marine debris; (4) injuries; and (5)

deaths.

Reproduction

Parturient females were identified when possible, and birth and weaning

information was recorded. Because parturient females often nurse pups other than their

own (Boness, 1990; Boness et al., 1998), efforts were made to identify pups and

document changes in nursing relationships from birth to weaning. A pup exchange

occurred when the pups of 2 lactating females were switched or one nursing female

suckled multiple pups. Typically, such exchanges occur during an aggressive interaction

between the 2 females. On other occasions, a mother and pup may become separated, and

1 or both seals will then actively seek and obtain another nursing relationship (Boness,

1990).

The average nursing period was calculated for some or all pups at each location. 

The average lactation period of parturient females was also calculated at FFS because

higher subpopulation density and frequent pup exchanges (Boness, 1990; Boness et al.,

1998) made it difficult to track individual pups and determine their nursing period. 

Nursing or lactation periods were defined as the number of days from birth until the end

of the last nursing relationship. Temporary breaks (e.g., if a mother and pup became

separated and 1 or both seals subsequently obtained another nursing relationship) were

not subtracted from the total. When the exact birth or weaning date was not known, but

occurred within a range of 4 days or less, then the midpoint of that range was used as the

start or end date for calculation of average nursing or lactation period. Nursing or

lactation data were not used if the birth or weaning range exceeded 4 days, or if the pup

died or disappeared before weaning.

Factors Affecting Survival

The origins of a wide range of injuries were distinguished based upon

characteristic wound patterns described in Hiruki et al. (1993). Injuries were documented

if they were related to mounting, large shark, or entanglement or if they were considered

severe enough to possibly affect survival. Injuries were considered severe and were

summarized if they consisted of (1) 3 or more abscesses, each <8 cm in diameter, or 1

abscess with a diameter >8 cm; (2) an amputation of at least half a flipper (either

foreflipper or hindflipper); (3) at least 3 punctures or gaping wounds, if largest dimension

was <8 cm, or 1 gaping wound with a maximum diameter-largest dimension >8 cm; or

(4) densely spaced (overlapping) scratches, abrasions, or lacerations covering an area

equivalent to half the dorsum or evidence of extensive underlying tissue damage (e.g., an

uneven or darkened surface of the injured area, leaching fluids), or if they impaired seal

movement. Major healed injuries incurred since the previous season were documented

but not included in summaries.

A seal was listed as dead if its death or carcass was observed. Deaths summarized

here include carcasses found at the beginning of the field season if the seal had clearly
6

 

1Reference to trade names does not imply endorsement by the National Marine

Fisheries Service, NOAA.

died during the calendar year. A seal was listed as probably dead if it sustained severe

injuries or was emaciated (with skeletal structure clearly evident) and subsequently

disappeared. In addition, one of the following conditions must have been satisfied to

place a seal in the "probably dead" category: (1) the seal was lethargic, had difficulty

moving, or floated listlessly in the water, and disappeared more than a week before the

end of data collection; or (2) the seal was in a deteriorating condition (loss of weight,

enlargement of abscesses, sloughing of skin) and disappeared a minimum of 10 surveys

or 1 month before the end of data collection (whichever was longer). Nursing pups were

listed as probably dead if they disappeared within 3 weeks of birth.

Multiple male aggression (or “mobbing”) and other mating-related male

aggression was observed and recorded. By definition, multiple male aggression occurred

when more than 1 male attempted to mate with a single seal, usually an adult female or

immature seal of either sex, causing injury or death of that seal (e.g., Alcorn, 1984). 

Single male aggression was defined as any incident when 1 adult or subadult male

repeatedly bit the dorsum, attempted to mount, and tried to prevent the escape of another

seal. These incidents were summarized in this report if they simultaneously involved

more than 1 male aggressor or resulted in at least 1 puncture or gaping wound (missing

skin or extending into the blubber layer) or > 15 scratches to the dorsum or flanks. Postaggression aggregations were also summarized; these were groups of males congregated

on the beach, attending a seal with new mounting injuries as described above.

Individual Identification

During censuses and patrols, individual seals were identified with tags, applied

bleach marks, scars, or natural markings. After weaning, pups were tagged on each hindflipper with a colored plastic Temple Tag,®1

 uniquely coded to indicate island or atoll

subpopulation, year of birth, and individual identification number (Gilmartin et al., 1986). 

In addition, a passive integrated transponder (PIT) tag was implanted subcutaneously in

the posterior dorsum of most weaned pups (see Lombard et al., 1994, for detailed tagging

procedures).

Colored plastic Temple Tags have been applied to nearly all weaned pups since

1981 at Kure Atoll, 1982 at Lisianski Island, 1983 at Laysan Island and Pearl and Hermes

Reef, 1984 at French Frigate Shoals, and 1995 at Midway Atoll. Pups at Midway Atoll,

Necker and Nihoa Islands, and the main Hawaiian Islands have been tagged

opportunistically since 1983. Since 1991, PIT tags have also been implanted

subcutaneously in the ankle (1991) or the dorsum (all subsequent years) of most weaned

pups. 

During 2001, untagged immature and adult seals were opportunistically tagged

with Temple Tags uniquely coded to indicate that their ages and birth locations were
7

unknown. These seals also received PIT tags. Seals with lost or broken tags were retagged

to maintain their identities.

Seals were bleach-marked for individual identification (Stone, 1984), using the

solution described in Johanos et al. (1987). Molting seals were re-marked with bleach to

maintain their identities until the next molt. Some nursing pups were also bleach-marked

prior to the postnatal molt to facilitate identification during the nursing period.

Tags, scars, other natural markings, and any applied bleach marks were sketched

by hand on a scar card for each seal, and this card was revised throughout the field season

to maintain a current description of the identifying marks of each seal. Digital and film

photographs of scars and natural markings were added to individual identification files

begun during 1981 or 1982.

Subpopulation size and composition were estimated at locations where observers

rarely encountered new unidentified seals during the latter part of the field season. These

statistics included all individuals observed alive at the location from March through

August and all known parturient females and pups born anytime during the year. 

The movement of seals between island or atoll subpopulations within and between

years complicates the estimation of subpopulation size and composition. This is

particularly true at Midway Atoll, where a number of the observed seals were tagged at

other locations (primarily Kure Atoll and Pearl and Hermes Reef). Therefore,

standardized rules for assigning each identified seal to just one subpopulation are applied

as follows: If a seal was observed at more than one location during March-August, it was

included in the subpopulation where it was sighted nearest to May 15, unless it pupped or

molted at another location. A parturient female was always included in the subpopulation

where she pupped, and a nonparturient seal was included in the subpopulation where it

molted. Pups were always included in the subpopulation where they were born.

Measurements of Seals

Pups were measured to provide information on condition and maternal

provisioning. Measurements were taken as soon after weaning as possible, and

measurements taken within 2 weeks after weaning were included in summaries. 

Measurements included straight dorsal length (Winchell, 1990) and axillary girth

(American Society of Mammalogists, 1967). Older animals captured for foraging

ecology, health, or disease studies were also measured.

Collection of Samples

Samples were collected for a DNA tissue bank, pathology analysis, investigation

of food habits, and documentation of marine debris. Tissue punches for DNA were

collected during tagging efforts for all newly tagged or retagged seals and during

necropsies on seals that had died recently. Samples of placentas found with or from

“aborted fetuses” or deceased perinatal pups were also collected. 
8

For each dead seal recovered, an external examination was made, photographs

were taken, and external measurements and observations were recorded. For a recent

death, an internal examination was made, and samples of tissue, organs, parasites, and

stomach contents were collected. Necropsy procedures and sample collection methods are

adapted from Winchell (1990).

Scat and spew samples were collected opportunistically for analysis of food habits

(Alcorn, 1984). These samples were collected from seals of known sizes and sex classes

when possible. 

Nets, lines, ropes, and other debris capable of entangling seals and turtles were

documented and inventoried. From 1982 to 1998, potentially entangling marine debris

was incinerated on site. Beginning in 1999, because of new Fish and Wildlife Service

regulations, marine debris was not handled in this manner at most sites. At Kure Atoll,

dangerous or entangling debris was destroyed by incineration, following the methods

described in Johanos and Kam (1986). At all other locations, debris was cut into

manageable-sized pieces and placed in storage bins or secured piles at centralized

locations for subsequent removal by ship.
9

CHAPTER 2. THE HAWAIIAN MONK SEAL ON

FRENCH FRIGATE SHOALS, 2001

Suzanne M. Canja, Brenda L. Becker, Allan D. Ligon, and Sean A. Hayes
24°

OO'N I \ ~ 

50' 

40' 

20 km 

23° I 

Contours in fathoms 

30' 

40' 30' 20' 1O' 16

Fig. 2.1. French Frigate Shoals in the Northwestern Hawaiian Islands. Islands are: Disappearing (D

(LG), Round (R), Shark (S), Tern (Tn), Trig (Ir), and Whaleskate (WS). 
11

The largest subpopulation of Hawaiian monk seals is located at French Frigate

Shoals (FFS, lat. 23°45'N, long. 166°10'W), ca. 830 km northwest of Oahu in the

Northwestern Hawaiian Islands. This atoll is part of the Hawaiian Islands National

Wildlife Refuge (Fig. 1.1) and consists of 9 permanent islets (Disappearing, East, Gin,

Little Gin, La Perouse Pinnacles, Round, Shark, Tern, and Trig), 3 semipermanent islets

(Bare, Mullet, and Whaleskate), and several transient sand spits (Fig. 2.1). 

RESEARCH

The National Marine Fisheries Service (NMFS) began research on Hawaiian

monk seals at FFS in 1982. During 2001, research was conducted by NMFS from

March 8 to March 12 and May 13 to October 1. Incidental observations were recorded by

U.S. Fish and Wildlife Service (USFWS) personnel during the rest of the year. The

perimeters of the 5 larger islets (East, Gin, Little Gin, Tern, and Trig) were divided into

sectors using artificial or natural landmarks. Research activities specific to this

subpopulation in 2001 included (1) monitoring and removal of Galapagos sharks preying

on monk seal pups at Trig Islet, (2) tagging of Galapagos and tiger sharks to determine

movement patterns within the atoll, (3) translocation of newly weaned pups to reduce

their risk of shark attack, (4) night observations of mom/pup pairs to determine their

nocturnal aquatic activity and the potential for night shark attacks, (5) retagging or newly

tagging seals, (6) investigation of juvenile foraging ecology using seal-mounted video

cameras (CRITTERCAMS) and time-depth recorders (TDRs), (7) assessment of seal

foraging using archival movement recorders imbedded in simulated benthic “rocks”, (8)

videographic surveys of benthic habitat, (9) collection of reef vertebrates and

invertebrates for Hawaiian monk seal prey fatty acid analysis, and (10) removal of marine

debris and assessment of accumulation rates within the lagoon.

Censuses and Patrols

Atoll-wide censuses (n = 17) were conducted every 7 d, on average, from May 29 

to September 18. Each atoll census required 2 days to complete, and data collection began

between 0855 and 1525 and ended between 1106 and 1830 Hawaii Standard Time. La

Perouse Pinnacles were not routinely surveyed as there are no seal haulout sites available. 

 

Individual islet censuses and patrols were scheduled to ensure that the entire atoll

was monitored at least once each week during May 16-September 19. Frequency of

surveys was higher at islets where most pups were born or at locations in close proximity

to these islets (i.e., Bare and Mullet); thus, Trig was monitored on average every 1-3 days;

Bare, East, Gin, Little Gin, Mullet, Round, and Tern averaged every 3-4 days; and

Disappearing, Shark, and Whaleskate Islets averaged every 5-7 days. Whaleskate, Bare,

and Mullet Islets were rarely above water during the sampling season. 
12

Individual Identification

A total of 331 individuals (268 excluding pups) were identified by existing or

applied tags, bleach marks, scars, or natural markings. Bleach marks were applied to 39

seals, including 16 nursing pups. Forty weaned pups were tagged with Temple Tags, 35

of which also received a passive integrated transponder (PIT) tag. Ten adult seals (7

males and 3 females) were tagged with Temple Tags and a PIT tag. 

Collection of Samples

Eighty-four scat and 7 spew samples were collected. Skin punches were collected

from 48 seals during tagging and a shed molt sample was collected from 1 seal. Tissue

samples were collected from 6 necropsied seals and skeletal samples from 7 carcasses. 

In addition, 1 juvenile and 4 pup carcasses (1 fetus, and 2 late-term and 1 full-term

abortions) were collected for necropsy. Three fresh placentas were collected. Health and

disease samples were collected from 2 seals and a dead pilot whale. Forty-six dried ticks

were collected to supplement health and disease investigations. In total, 78 items of

potentially entangling debris were inventoried and stored for removal by ship. 

Special Studies

Galapagos Shark Observations, Deterrence, and Culling from Trig Islet

From June 3 through September 6, Trig Islet was monitored daily for a total of 86

days (excluding nine weather/logistical days) to document the presence of Galapagos

sharks and their predatory behavior towards monk seal pups. Five sharks that exhibited 

predatory behavior were removed; specimen samples were collected from 4 of these

animals. One Galapagos shark that had recently been instrumented with an acoustic tag

was recaptured and released. This shark had not exhibited predatory behavior but was

caught incidental to other aggressive Galapagos in the area at the time. Two Galapagos

shark attacks on nursing pups were observed, 1 of which was fatal.

Tagging of Tiger, Galapagos, and Gray Reef Sharks

During June and July, 13 sharks (3 tiger, 2 Galapagos, 8 gray reef) were captured,

measured, and tagged around East or Trig Islets. Each shark received a highly visible

identification tag in the dorsal fin, and Galapagos and tiger sharks were additionally

instrumented with acoustic tags to monitor each shark’s movement within the atoll.

Movement of acoustic tagged sharks from the previous season (1 Galapagos and 7 tiger

sharks) continued to be monitored. This project is part of a study initiated in 2000 and 

conducted by California State University Long Beach, Hawaii Institute of Marine Biology,

and the NMFS Narragansett Laboratory.
13

Three additional sharks (1 gray reef, 1 whitetip, and 1 tiger shark) were tagged with

colored, numbered Floy®

 spaghetti tags for future identification incidental to the study on

Galapagos shark predation mitigation.

Translocation of Weaned Pups

Eighteen newly weaned pups were translocated, typically on the day of weaning, to

other islets within the atoll with lower shark activity in efforts to decrease their risk of

shark predation. All 17 newly weaned pups on Trig Islet were translocated; 8 pups to Little

Gin, 6 pups to Gin, and 3 seriously shark-bitten pups to Tern Islet. In addition, a newly

weaned pup with a fresh shark bite on Round Islet was translocated to Little Gin. One of

the Trig-born pups who had been translocated to Little Gin was recaptured 2 months later

on Trig with a fresh shark bite; it was then translocated to East Islet.

Night Observations of Mother/Pup Pairs on Trig Islet

During the evenings of June 23-24 and July 5-6, mother/pup pairs were monitored

for 12 hours from sunset to sunrise to determine their nocturnal aquatic activity as it

relates to shark predation risks. Half the pups present entered the water before daylight (10

of 20 focal group observations).

Foraging Ecology, Health, and Disease

In July and August, in collaboration with the National Geographic Society, a pilot

study was conducted to investigate juvenile seal foraging ecology at FFS; 2 juveniles (1

male, 1 female) were instrumented with a CRITTERCAMS, TDR, and a VHF radio

transmitter. The CRITTERCAMS were removed after 3 and 11 days. The VHF radio

transmitters and TDRs were left on the seals an additional 4 and 14 days to investigate

whether cameras might affect the seals’ diving behavior. In addition, blood, fecal,

bacteriological and virological samples, and blubber samples were collected from both

seals to supplement health and disease investigations.

In August, archival movement recorders imbedded in simulated “rocks” were

deployed in seal foraging sites to monitor year-round foraging activity. Videographic

surveys were also conducted to map benthic habitat types. In addition, researchers also

collected reef vertebrates and invertebrates for analysis of fatty acids in potential monk

seal prey.

RESULTS

Subpopulation Abundance and Composition

The mean (±SD) of 17 atoll censuses was 113.1 seals (± 14.0) including pups and

87.4 seals (± 13.1) excluding pups (Table 2.1). Total seals identified as part of the springsummer subpopulation were 325 individuals, 262 excluding pups (Table 2.2). This number
14

is a subset of the total identified in the calendar year and is an unknown proportion of the

total subpopulation as many of the older, untagged seals could not be uniquely identified.

The numbers of tagged known-age seals born at FFS during the period from 1984 to 2000,

and resighted at any location in 2001, are summarized in Table 2.3.

Reproduction

At least 63 pups were born at FFS in 2001; 42 were successfully weaned, 2 were

still nursing at the end of the camp, and 19 died or disappeared prior to weaning (Table

2.4a). Nursing periods and measurements of weaned pups are summarized in Table 2.4b. 

The mean (±SD) lactation period for 30 females was 35.2 d (±6.1 d). Twelve pup

exchanges were documented between 14 adult females; 2 of these events were observed

and another occurred when researchers intervened to improve the survival of a smaller

nursing pup. Two births were observed, 1 of which was videotaped. 

Interatoll Movement

Interatoll movement was documented for 3 seals that completed 3 movements

between FFS and either Laysan or Necker Island (Tables 2.5a and b). 

Factors Affecting Survival

Attacks by large sharks, mounting attempts by male Hawaiian monk seals,

emaciation, and unknown factors resulted in 35 life-threatening conditions, which led to

the confirmed deaths of 14 seals (including 8 perinatal deaths) and the probable death of

13 seals; 9 of which were nursing pups (Table 2.6). Seven of the nursing pup

disappearances occurred at Trig, 1 at Gin, and 1 at Round Islet. Shark attack was the

suspected cause for the disappearances for all of the nursing pups at Trig and Round Islets;

as all of these pups appeared healthy and normal, and there were numerous observations of

Galapagos sharks patrolling, attempting, and successfully attacking pups on Trig Islet. A

high proportion of all the FFS live-born pups were attacked by sharks; excluding perinatal

deaths, 20.4 % of the pups (11/54) were injured, including 7 moderately to severely

injured pups (3 died) and 4 pups that received minor bites not summarized on Table 2.6. 

No incidents of adult male aggression were observed; however, 2 seals received

injuries characteristic of male mounting. No seals were entangled in marine debris. Three

immature female seals (a weaned pup, juvenile, and subadult) were found behind the

deteriorating seawall at Tern Island and were either removed or guided out uninjured by

researchers. In addition to incidents summarized in Table 2.6, an adult female seal had a

healed hindflipper amputation from a shark attack that had occurred since the previous

field season, and an aborted fetus was found on Trig Islet in May.
15

ACKNOWLEDGMENTS

We acknowledge the support of the USFWS, Hawaiian Islands National Wildlife

Refuge staff and volunteers, particularly Anthony Palermo for his gracious support and

assistance with data collection, necropsies, and rescuing a seal stranded behind the

seawall. Special thanks to Allison Veit and USFWS volunteer Sarah Ward for their

assistance with a seal necropsy. Thanks to Dominique Horvarth for her cheerful logistical

support, always there to help get our equipment and supplies out to Tern Islet. We also

thank Kyler Abernathy, Dr. Robert Braun, Aaron Dietrich, Frank Parrish, John Peshon,

and Brad Ryon for their assistance with translocation of newly weaned pups and other

noteworthy seal observations on Trig Islet. We additionally thank Aaron Dietrich for

documenting pupping on East Islet during turtle nesting studies. We thank the captain,

officers, and crew of the NOAA ship Townsend Cromwell and the pilots of Pearl Pacific

Enterprises for logistical assistance.

17

TABLES

for French Frigate Shoals

19

Table 2.1.--Summary statistics for atoll censuses (n = 17) of Hawaiian monk seals at French

Frigate Shoals from May 29 to September 18, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 67.4 10.4

Male 20.5 4.1

Female 41.0 8.9

Unknown 5.8 4.2

Subadults 11.0 4.4

Male 4.3 2.2

Female 5.8 2.7

Unknown 0.9 0.9

Juveniles 8.9 2.9

Male 3.4 1.5

Female 5.1 2.1

Unknown 0.5 0.6

Pups 25.8 2.9

Male 13.2 3.0

Female 10.5 3.1

Unknown 2.0 2.2

Non-pup total 87.4 13.1

Grand total 113.1 14.0
20

Table 2.2.--Composition of the Hawaiian monk seal subpopulation at French Frigate Shoals

 during the spring and summer of 2001. These numbers are an unknown

 proportion of the entire subpopulation as many untagged adults could not be

 uniquely identified. All known parturient females and pups born during the

 calendar year are included. 

Number of seals

Size Male Female Unknown Total

Sex ratio

male:female

Adults 79a

119a

0 198a

0.7:1

Subadults 13 16 0 29 0.8:1

Juveniles 13 22 0 35 0.6:1

Pups 33b

27c

3

d

63 1.2:1

Non-pup total 105e

157e

0 262e

0.7:1

Grand total 138b,e 184c,e 3

d

325e0.8:1

a

 These numbers are an unknown proportion of the entire adult subpopulation.

b

 Includes 5 perinatal pup deaths.

c

 Includes 2 perinatal pup deaths.

d

 Includes 2 perinatal pup deaths, excludes 1 fetus.

e

 These numbers are a minimum subpopulation estimate.
21

Table 2.3.--Summary of tagged known-age seals born at French Frigate Shoals and resighted

 at any location in 2001.

Cohort year

Age

(years) Sex

Number

originally

tagged

Number

resighted

 in 2001

1984 17 Male

Female

49

43

 9a

13b

1985 16 Male

Female

48

38

3

a

 9b

1986 15 Male

Female

52

48

 7 a

18a,b

1987 14 Male

Female

55

51

 7

8

1988 13 Male

Female

52

62

4

5

1989 12 Male

Female

51

50

7

7

b

1990 11 Male

Female

38

41

1

8

b

1991 10 Male

Female

24

44

1

4

b

1992 9 Male

Female

36

55

2

 10b

1993 8 Male

Female

40

39

2

2

1994 7 Male

Female

47

48

1

7

b

1995 6 Male

Female

29

26

2

 12a

1996 5 Male

Female

39

30

3

3

1997 4 Male

Female

32

19

1

0

1998 3 Male

Female

49

39

 7

 9

1999 2 Male

Female

30

30

7

6

2000 1 Male

Female

27

30

 7

17

a

 Cohort survivors include seals removed from French Frigate Shoals for rehabilitation

 that remain in permanent captivity (n = 14).

b

 Cohort survivors include seals removed from French Frigate Shoals for rehabilitation or

 direct translocation and released at Kure or Midway Atoll (n = 19). 
22

Table 2.4a.--Summary of Hawaiian monk seals born at French Frigate Shoals in 2001.

Event

Number of pups

Male Female Unknown Total

Born 33 27 3

a

63

Died/probably died at/or

prior to weaning

10 6 3 19

Still nursing 1

b

1

b

0 2

b

Weaned 22 20b

0 42

Tagged 21c

 19b,d 0 40

a

 Excludes a fetus. 

b

 Although 3 pups (a male and 2 females) were still nursing at the end of the NMFS

 field camp, 1 of the female pups was confirmed weaned and was tagged in June 2002. 

c

 One pup was severely injured by a shark, precluding safe restraint, and disappeared

 shortly after the injury healed in July.

d

 A pup born and weaned after the NMFS camp was tagged in December by USFWS.

 One newly weaned pup died shortly after receiving a severe shark bite and was not

 tagged. 

 

Table 2.4b.--Summary of nursing periods and measurements of weaned pups at French

 Frigate Shoals in 2001. Nursing periods were calculated where birth and

 weaning dates were both known or occurred within a range of 4 days or less.

 All measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm)

Straight dorsal

length (cm)

Mean 36.2 105.2 124.8

St. dev. 5.1 10.0 6.6

n 19 38 38
23

Table 2.5a.–Documented movement of Hawaiian monk seals to French Frigate Shoals

 from other locations in 2001, summarized by movements between 2

 locations. No seals made more than 1 trip.

Original location Number of trips, size, and sex class

Laysan Island 1 adult male

Necker Island 1 adult female

Table 2.5b.–Documented movement of Hawaiian monk seals from French Frigate Shoals

 to other locations in 2001, summarized by movements between 2 locations.

 No seals made more than 1 trip. 

Destination Number of trips, size, and sex class

Laysan Island 1 adult female
24

Table 2.6.--Factors affecting Hawaiian monk seal survival at French Frigate Shoals in

 2001. 

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Adult Female 1 1 0 0

Weaned pup Male

Female

1

2

1

1

0

1

0

0

Nursing pup Male 4 2 2

a

0

Mounting by Males

Adult Female 1 1 0 0

Subadult/Adult Unknown 1 0 0 1

Entanglement

(none observed)

Emaciation

Adult Male 1 0 1

b

0

Juvenile Male

Female 

2

2

0

0

0

1

c

2

1

b

Unknown

Adult Male

Female

1

1

1

1

0

0

0

Juvenile Female 1 0 1 0

Nursing pup Male

Female

Unknown

8

6

3

0

0

0

5

d

2

d

1

e

3

4

2

f

a

 The fatal attack of 1 pup by a Galapagos shark was observed.

b

 The seal was in poor condition and had sustained a fresh shark injury just prior to

 death/disappearance.

c

 The seal sustained a blunt/trauma blow to the head prior to death.

d

 All were perinatal deaths; none of the pups were seen alive.

e

 Bones from the flattened carcass were the size of a nursing pup.

f

 Only a fresh placenta was found; no mother or carcass observed.
25

CHAPTER 3. THE HAWAIIAN MONK SEAL ON

LAYSAN ISLAND, 2001

Dorothy M. Dick, Alison C. Roberts, Jennifer R. Stephenson,

and Jacqueline M. Pearson
26 


,* ...... ' 

.

, 

.. 25°' 

47'N 

46' 

N 

~ 1 

0.5 km 

45' I 

45' 46' 171°47'W 

Fig. 3.1 Laysan Island in the Northwestern Hawaiian Islands. 

I 
27

Laysan Island (lat. 25°42'N, long. 171°44'W) is located ca. 1,300 km northwest of Oahu

in the Northwestern Hawaiian Islands (Fig. 1.1). This island lies within the Hawaiian

Islands National Wildlife Refuge and is one of the 6 primary haulout and pupping

locations of the Hawaiian monk seal (Fig. 3.1).

RESEARCH

The National Marine Fisheries Service (NMFS) began research on Hawaiian monk seals

at Laysan Island in 1981. In 2001, research was conducted by NMFS during March 18-

July 26 and October 5-19. Incidental observations were recorded by U.S. Fish and

Wildlife Service (USFWS) personnel during the remainder of the year. The perimeter of

the island (ca. 11 km) was divided into 20 sectors using artificial or natural landmarks

(Fig. 3.1). Research objectives specific to this subpopulation in 2001 included (1)

assessment of maternity and pup exchanges; (2) documentation of male behavior,

including aggression; (3) observation of seals for signs of ill health; and (4) 

epidemiological sampling for health and disease assessment studies. The latter 2

objectives were added in late March when 4 young seals were found dead over a 1-week

period leading to declaration of an unusual mortality event (UME). October research

objectives included satellite transmitter deployment, epidemiological sampling, and

retagging.

 

Censuses and Patrols

Census, patrols, and incidentals were scheduled to ensure that the entire island perimeter

was monitored at least once daily during March 29-July 13. Censuses (n = 25) were

conducted by 2 observers every fourth day from April 14 to July 21, beginning at 1300

Hawaii Standard Time and continuing for 2.0 to 3.1 h.

Standardized behavior patrols (n = 21) were conducted on noncensus days from April 16

to July 11 to assess behavior of adults and large subadults, including male aggression.

During behavior patrols, observer attention was directed out to sea as much as possible,

as multiple male aggression has been observed most frequently in the water. 

Full-island standardized incidental surveys (n = 67) were conducted on noncensus and

nonbehavior patrol days from March 18 to July 12 to record females with pups, weaned

pups, injured seals, and molting animals. If observed, major behavioral interactions (i.e.,

male aggression) were also recorded. Additional partial island incidental surveys were

conducted as needed. 

Individual Identification
28

A total of 302 individuals (266 excluding pups) were identified by existing or applied

tags, bleach marks, scars, or natural markings. Bleach marks were applied to 231 seals,

including 31 nursing pups. All weaned pups (n = 33) were tagged with Temple Tags and

passive integrated transponder (PIT) tags. During epidemiological sampling in April, 2

juvenile females (known-age yearlings) were newly tagged with Temple Tags and PIT

tags, and 3 males (2 juveniles and a subadult) were retagged with Temple tags or PIT

tags. Two adults were newly tagged with Temple Tags and PIT tags in October; a female

and an unidentified male with old tag holes. Additionally, 15 seals (7 adult males, 3 adult

females, 1 subadult male, 1 subadult female, 2 juvenile females and a weaned female

pup) were retagged with Temple tags and/or PIT tags in October.

Sample Collection

Eighty-six scat and 7 spew samples were collected. Skin punches were collected from 32

weaned pups during tagging, and from 23 older seals. Various epidemiological samples

were collected from 14 seals during the April health and disease study. No molt samples

were collected. Five necropsies were performed; tissue and skeletal samples were

collected from each of the seal carcasses. The skull from a dead adult female was also

collected. In total, 315 pieces of potentially entangling debris were inventoried; 313 items

were securely stored on Laysan to be removed at a later date. The remaining 2 pieces

were removed from entangled seals, collected, and brought back to Honolulu.

Special Studies

Health, Disease, and Foraging Ecology

In late March 2001, NMFS staff found and necropsied 4 dead seals (3 yearlings and one

2-year old) over a 1-week period at Laysan Island. Under provisions of the Marine

Mammal Protection Act of 1972, the Working Group on Marine Mammal Unusual

Mortality Events (UME) determined that a UME involving juvenile Hawaiian monk seals

was occurring at Laysan. Declaration of the UME was based primarily on the deaths at

Laysan Island, but deaths and unusual symptoms/behaviors were reported at other

locations, and investigation of the UME included other primary monk seal subpopulations

in the Northwestern Hawaiian Islands to assess possible range-wide impacts. A team was

deployed to visit the islands, necropsy dead seals, visually evaluate the health of seals

observed, collect epidemiology samples from all unhealthy looking seals, and sample

healthy looking juveniles. New tagging, retagging, and PIT tagging of sampled seals

occurred opportunistically.

Blood, fecal samples, virological and bacteriological swabs, and blubber biopsies were

collected at Laysan Island from April 18 to April 27. Samples were collected from 3

unhealthy juvenile males and from 10 healthy immature seals including 2 subadults (a

male and female) and 8 juveniles (4 males and 4 females). Additional vaginal swabs were
29

obtained without restraint from an adult female whose pup died perinatally. Although no

additional juvenile deaths occurred, at least 3 of the yearlings sighted in March/April

were no longer seen by July. 

During October 2001, a field team of researchers from NMFS and Hubbs Sea World

Research Institution was deployed (1) to attach satellite-linked dive recorders (SLDRs) in

order to characterize at-sea habitat use, (2) to collect epidemiological sampled (blood,

swabs, blubber, etc.) for health and disease assessment, and (3) to retag or newly tag seals

to facilitate individual identification in the subpopulation. A total of 37 seals were

handled. Thirty seals were sampled for the health and disease assessment and received

SLDRs: 16 received SLDRs and temple and/or PIT tags (including 2 newly tagged

weaned pups) and 14 received SLDRs only. In addition, 3 seals received Temple and/or

PIT tags, and 4 seals were immediately released due to molt status.

RESULTS

Subpopulation Abundance and Composition

The mean (±SD) of 25 censuses was 89.4 seals (± 11.3) including pups, and 70.6 seals (±

11.2) excluding pups (Table 3.1). The total spring-summer subpopulation was 292

individuals, 256 excluding pups (Table 3.2). This number is a subset of the total

identified in the calendar year. The overall sex ratio was 0.8:1 (130 males: 160 females). 

The numbers of tagged known-age seals born at Laysan Island during the period from

1983 to 2000, and resighted at any location in 2001, are summarized in Table 3.3. 

Reproduction

At least 36 pups were born at Laysan Island in 2001; 33 were successfully weaned and 3

died perinatally (Table 3.4a). Nursing periods and measurements of weaned pups are

summarized in Table 3.4b. The birth rate was measured as the number of pups born

divided by the number of adult-sized females in the subpopulation X 100 was 40.9%

((36/88) X 100). At least 17 pup exchanges occurred between 13 nursing females; none

were observed.

Interatoll Movement

Interatoll movement was documented for 21 seals that completed a total of 35 movements

between Laysan Island and French Frigate Shoals, Lisianski Island, Pearl and Hermes

Reef, or Maro Reef (Tables 3.5a and b).

Factors Affecting Survival
30

Attacks by large sharks, mounting attempts by male Hawaiian monk seals, entanglement

in marine debris, emaciation, and a number of unknown factors led to 26 life-threatening

conditions, which resulted in the confirmed deaths of 9 animals and the disappearance of

4 other seals (Table 3.6). Although no incidents of prolonged adult male aggression were

observed, 3 females (2 adults and a subadult) suffered moderate or severe dorsal injuries

indicative of male mounting. Four seals were entangled; 2 escaped unaided, 1 was

released by observers, and the fate of 1 was unknown. In addition to the incidents

presented in Table 3.6, one 3-year old was not seen after mid-April, two 2-year olds were

not seen after mid-June, 2 yearlings were not seen after early May, and 1 yearling was not

seen after late June. All these yearlings were in poor condition when they were last seen.

An adult female of medium condition pupped and nursed her pup for 32 days; upon

weaning she was obviously emaciated and not seen again after mid-June. 

ACKNOWLEDGMENTS

We acknowledge the support of the U.S. Fish and Wildlife Service, Hawaiian

Islands National Wildlife Refuge staff and thank the captain and crew members of the

NOAA ship Townsend Cromwell, the SS Midway and the USCG Cutter Kukui. Special

thanks are extended to Robert Braun, DVM and Brad Ryon for their assistance during the

UME, and to Bud Antonelis, Brad Ryon, Brent Stewart, and Pam Yochem, DVM, during

the satellite tagging camp. Additional thanks to David Carroll, Chris Depkin, Mary

Golden, Eric Lund, Amy Martin, Darrel Porter, Cindy Rehkemper, Alex Wegmann,

Joseph Wiggins, and Richard Young for their data collection, seal bleaching, debris

hauling, and disentangling assistance.
31

TABLES

for Laysan Island

33

Table 3.1.--Summary statistics for censuses (n = 25) of Hawaiian monk seals at Laysan

 Island from April 14 to July 21, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 45.2 7.2

Male 17.6 4.9

Female 26.0 5.1

Unknown 1.6 2.0

Subadults 14.8 5.1

Male 7.3 2.6

Female 7.2 3.2

Unknown 0.3 0.5

Juveniles 10.7 2.8

Male 5.2 1.7

Female 5.3 2.2

Unknown 0.2 0.4

Pups 18.8 3.3

Male 9.8 1.6

Female 8.9 2.3

Unknown 0.1 0.4

Non-pup total 70.6 11.2

Grand total 89.4 11.3
34

Table 3.2.--Composition of the Hawaiian monk seal subpopulation at Laysan Island

 during the spring and summer of 2001. Includes all known parturient females

 and pups born during the calendar year. 

Number of seals

Size Male Female Unknown Total

Sex ratio

male:female

Adults 72 88 0 160 0.8:1

Subadults 26 28 0 54 0.9:1

Juveniles 16 26 0 42 0.6:1

Pups 16 18 2 36 0.9:1

Non-pup total 114 142 0 256 0.8:1

Grand total 130 160 2 292 0.8:1
35

Table 3.3.--Summary of tagged known-age seals born at Laysan Island and resighted at

 any location in 2001.

Cohort year

Age

(years) Sex

Numb er originally

tagged

Number resighted 

in 2001

1983 18 Male

Female

10

10

1

6

1984 17 Male

Female

16

13

2

5

1985 16 Male

Female

16

14

1

4

1986 15 Male

Female

15

17

0

2

1987 14 Male

Female

13

15

3

6

1988 13 Male

Female

23

17

4

3

1989 12 Male

Female

16

13

2

2

1990 11 Male

Female

7

9

2

3

1991 10 Male

Female

18

13

7

4

1992 9 Male

Female

18

14

2

4

1993 8 Male

Female

23

14

4

5

1994 7 Male

Female

18

29

8

8

1995 6 Male

Female

16

21

7

9

1996 5 Male

Female

23

21

11

11

1997 4 Male

Female

19

16

5

7

1998 3 Male

Female

Unknown

24

20

1

15

10

0

1999 2 Male

Female

20

34

9

22

2000 1 Male

Female

14

20

7

9
36

Table 3.4a.--Summary of Hawaiian monk seals born at Laysan Island in 2001.

Event

Number of pups

Male Female Unknown Total

Born 16 18 2 36

Died prior to weaning 0 1 2 3

Weaned 16 17 0 33

Tagged 16a

17b0 33

a, bIncludes 2 pups weaned in August and tagged by the October NMFS camp.

Table 3.4b.--Summary of nursing periods and measurements of weaned pups at Laysan

 Island in 2001. Nursing periods were calculated where birth and weaning

 dates were both known or occurred within a range of 4 days or less. All

 measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm)

Straight dorsal

length (cm)

Mean 36.6 100.1 124.2

Standard

deviation

3.7 12.4 8.1

n 32 31 31
37

Table 3.5a.–Documented movement of Hawaiian monk seals to Laysan Island from other

locations in 2001, summarized by movements between two locations. Three

seals made more than 1 observed trip.

Original location Number of trips, size, and sex class

French Frigate Shoals 1 adult female

Lisianski Island 13 adult female

 2 subadult male

 1 subadult female

 1 juvenile female

Pearl and Hermes Reef 1 subadult female 

Table 3.5b.–Documented movement of Hawaiian monk seals from Laysan Island to other

locations in 2001, summarized by movements between 2 locations. Two

seals made more than 1 observed trip.

Destination Number of trips, size, and sex class

French Frigate Shoals 1 adult male

Lisianski Island 10 adult female

 2 subadult male

 1 subadult female

Pearl and Hermes Reef 1 juvenile male

Maro Reef 1 weaned male pup 
38

Table 3.6.--Factors affecting Hawaiian monk seal survival at Laysan Island in 2001.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Adult Male

Female

3

 2 

3

1

0

0

0

1

Juvenile Male 1 1 0 0

Weaned Pup Female 1 1 0 0

Mounting by Males

Adult Female 2

a 2 0 0

Subadult Female 1

 1 0 0

Entanglement

Adult Male

Female

2

b

1

c

0

0

0

0

0

0

Unknown Unknown 1

d

0 0 0

Emaciation

Adult Male 1 0 0 1

e

Juvenile Male 2 0 0 2

f

Unknown

Adult Male

Female 

1

1

0

0

 1g

1

0

0

Juvenile Male

Female

1

3

0

0

1

h

3

i

0

0

Nursing pup Female

Unknown

1

2

0

0

1

j

2

k

0

0

a

 Includes 1 seal whose pup died perinatally.

b

 One seal was released by observers and sustained no injuries. The other seal was

 observed entangled in November by USFWS personnel but freed itself by Jan 2002.

c

 Seal disentangled itself and sustained no injuries from the entanglement.

d

 Untagged seal was observed entangled in November by USFWS, fate unknown.

e

 An older seal in extremely poor, deteriorating condition and noted as lethargic.

f

 One seal in deteriorating condition, emaciated with wobbly movements. The other seal

 had minor shark injuries, poor to very thin condition with lethargic/abnormal behaviors

 noted several times. 

g

 Seal washed up after a storm with its head and a large portion of its abdominal area

 missing. It is unknown whether these injuries were sustained pre- or post-mortem. 

h

 One of 4 seals that died within a week period, appeared to be in good condition.

i

 Three of the 4 seals that died within a week period. Seals appeared to be thin.

j

 Pup was never observed alive.

k

 Includes 1 pup who was born alive but appeared to have difficulty moving its left

 foreflipper; researchers observed the pup drown.
39

CHAPTER 4. THE HAWAIIAN MONK SEAL ON 

LISIANSKI ISLAND, 2001

Jacqueline M. Pearson, Erin T. McCarthy, and Erin E. Moreland
40 


26°' 

4' 

30"N 

* 

4' 

N 

4' 

30" 

1 

Fig. 4.1 

58'30" 58' 

Lisianski Island in the Northwestern Hawaiian Islands. 

1 73° 57'30"W 

, 

\.1 ve t . \..-­ ge atlOn 

'~ line 

~20 

. 

. 

0.5 km 
41

Lisianski Island (lat. 26°02'N, long. 174°00'W) is one of the primary haulout and

pupping locations of the Hawaiian monk seal. The island is located ca. 1,760 km

northwest of Oahu (Fig. 1.1) and is surrounded by Neva Shoal, a shallow reef bank within

the Hawaiian Islands National Wildlife Refuge (Fig. 4.1).

RESEARCH

The National Marine Fisheries Service (NMFS) began research on Hawaiian

monk seals at Lisianski Island in 1980. In 2001 research was conducted by NMFS during

March 12-July 22. Additional observations were conducted opportunistically by the

USFWS during August 15, 2001. The perimeter of the island was divided into 20 sectors

using artificial or natural landmarks (Fig. 4.1). Research activities specific to this

subpopulation in 2001 included (1) assessment of maternity and pup exchanges; (2)

documentation of male behavior, including aggression; (3) observing seals for signs of ill

health; (4) epidemiological sampling for health and disease assessment studies; and (5)

observations of seals satellite tagged in October 2000. Objectives 3 and 4 were added

after 4 seals were found dead within the first week of camp deployment. The seals found

dead were 1 perinatal pup, 1 juvenile, 1 adult, and 1 subadult seal. 

Censuses and Patrols

Census, patrols and incidentals were scheduled to ensure that the entire island

was monitored at least once daily during March 12-July 22. Censuses (n = 28) were

conducted by 2 observers every fourth day from March 21 to July 12, beginning at 1300

Hawaii Standard Time and continuing from 1.5 to 2.8 h. 

Standardized behavior patrols were conducted on 28 noncensus days from

March 19 to July 9 to assess behaviors of adults and large subadults, including male

aggression. During behavior patrols (n = 28), attention was directed out to sea as much as

possible since multiple male aggression has been observed most frequently in the water.

 

 Full-island standardized incidental surveys (n = 67) were conducted on noncensus

and nonbehavior patrol days during March 12- July 22 to record females with pups, sick

or injured seals, weaned pups, molting animals, and satellite-tagged seals. If observed,

major behavioral interactions (i.e., male mobbing/harassments) were also recorded.

Additional partial island surveys were conducted as needed.

Individual Identification

A total of 183 individuals (166 excluding pups) were identified by existing or

applied tags, bleach marks, scars, or natural markings. Bleach marks were applied to 143
42

individual seals, including 14 nursing pups. All weaned pups (n = 14) were tagged with

Temple tags and passive integrated transponder (PIT) tags (1 of these pups was

subsequently retagged twice in 2001). 

Collection of Samples

One hundred-two scat and 3 spew samples were collected. Skin punches were

collected from 14 weaned pups during tagging. Four necropsies were performed; tissue

and skeletal samples were collected from the seal carcasses. Additional tissue and skeletal

samples were collected from 1 adult male, and the skull from 1 subadult seal of

undetermined sex (both carcasses were too decomposed for a full necropsy). Various

epidemiology samples were collected from 2 juvenile seals (a male and female) during

the April health and disease study. Shed molt samples were collected from 10 individuals.

In total, 326 items of potentially entangling debris were inventoried; of these, 325 items

were stored to be removed from the island at a later date. One item removed from an

entangled seal was collected and brought to Honolulu. 

Special Studies

Health and Disease

Under provisions of the Marine Mammal Protection Act of 1972, the Working

Group on Marine Mammal Unusual Mortality Events (UME) determined that a UME

involving juvenile Hawaiian monk seals was occurring at Laysan (see the Laysan Island

chapter). A team visited Lisianski Island on April 17 and collected blood, fecal samples,

virological and bacteriological swabs, and blubber biopsies from 2 healthy juvenile seals

(a 2-year-old male and a 3-year-old female).

RESULTS

Subpopulation Abundance and Composition

The mean (±SD) of 28 censuses was 58.2 seals (± 6.8 ) including pups, and 49.1

seals (± 6.2) excluding pups (Table 4.1). The total spring-summer subpopulation was 178

individuals, 161 excluding pups (Table 4.2). This number is a subset of the total

identified in the calendar year. The sex ratio for older (>19 years of age) and unknown

aged adults was strongly skewed toward males at 2.5:1 (30 males:12 females), whereas

the ratio for younger adults (< 19 years of age) was at 0.9:1 (33 males: 37 females). The

numbers of tagged known-age seals born at Lisianski Island during the period from 1982

to 2000, and resighted at any location in 2001, are summarized in Table 4.3.
43

Reproduction

At least 17 pups were born at Lisianski Island in 2001: 14 were successfully

weaned, 2 died perinatally, and 1 probably died (Table 4.4a). Nursing periods and

measurements of weaned pups are summarized in Table 4.4b. The birth rate measured as

the number of pups born divided by the number of adult-sized females in the

subpopulation X 100 was 34.7% ((17/49) X 100). A minimum of 3 pup exchanges

occurred among 15 nursing females; researchers observed 1 of these incidents.

Interatoll Movement

Interatoll movement was documented for 17 seals that completed a total of 31

movements between Lisianski Island and either Laysan Island or Kure Atoll (Tables 4.5a

and b).

Factors Affecting Survival

Attacks by large sharks, entanglement in marine debris, emaciation, and

other/unknown factors led to 23 life-threatening conditions, which resulted in the

confirmed deaths of 6 animals and the probable death of 5 seals (Table 4.6). Two seals

were entangled, and subsequently released by observers with no further evident

complications. No incidents of prolonged adult male aggression or serious mounting

injuries were observed. In addition to the cases summarized in Table 4.6, an adult female

still had a chronic injury observed in previous field seasons, and the mummified carcass

of a subadult/adult seal of unknown sex was found at the beginning of the season. This

seal had died of unknown causes since the previous field season.

ACKNOWLEDGMENTS

We acknowledge the support of the U.S. Fish and Wildlife Service, Hawaiian

Islands National Wildlife Refuge staff. We thank the captain, officers, and crew of the

NOAA ship Townsend Cromwell and the SS Midway for logistical assistance. 

45

TABLES

for Lisianski Island

47

Table 4.1.--Summary statistics for censuses (n = 28) of Hawaiian monk seals at Lisianski 

 Island from March 21 to July 12, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 35.7 4.7

Male 17.5 3.6

Female 15.6 2.9

Unknown 2.5 1.7

Subadults 8.9 2.1

Male 6.1 1.8

Female 2.4 1.8

Unknown .4 .6

Juveniles 4.5 2.0

Male 1.8 1.3

Female 2.6 1.4

Unknown 0.0 .2

Pups 9.0 2.6

Male 3.0 1.2

Female 6.0 1.7

Unknown 0.0 0.2

Non-pup total 49.1 6.2

Grand total 58.2 6.8
48

Table 4.2.--Composition of the Hawaiian monk seal subpopulation at Lisianski Island

 during the spring and summer of 2001. Includes all known parturient females

 and all pups born during the calendar year.

Number of seals

Size Male Female Unknown Total

Sex ratio

male:female

Adults 63 49 0 112 1.3:1

Subadults 19 10 0 29 1.9:1

Juveniles 9 11 0 20 0.8:1

Pups 5 10 2 17 0.5:1

Non-pup total 91 70 0 161 1.3:1

Grand total 96 80 2 178 1.2:1
49

Table 4.3.--Summary of tagged known-age seals born at Lisianski Island and resighted at

 any location in 2001.

Cohort year

Age

(years) Sex

Number originally

tagged

Number resighted

in 2001

1982 19 Male

Female

7

6

2

1

1983 18 Male

Female

6

18

2

7

1984 17 Male

Female

10

5

4

2

1985 16 Male

Female

5

9

2

1

1986 15 Male

Female

11

9

5

3

1987 14 Male

Female

12

6

1

1

1988 13 Male

Female

10

8

 5

6

1989 12 Male

Female

–

--

–

--

1990 11 Male

Female

8

9

4

3

1991 10 Male

Female

9

6

4

2

1992 9 Male

Female

13

8

6

4

1993 8 Male

Female

4

9

1

2

1994 7 Male

Female

 4

5

1

1

1995 6 Male

Female

 7

10

2

2

1996 5 Male

Female

 9

13

2

1

1997 4 Male

Female

 10

9

5

3

1998 3 Male

Female

10

11

3

6

1999 2 Male

Female

16

11

 7

3

2000 1 Male

Female

9

9

2

4
50

Table 4.4a.--Summary of Hawaiian monk seals born at Lisianski Island in 2001.

Event

Number of pups

Male Female Unknown Total

Born 5 10 2 17

Died/Probably died prior to

weaning

0 1 2 3

Weaned 5 9 0 14

Tagged 5 9 0 14

Table 4.4b.--Summary of nursing periods and measurements of weaned pups at Lisianski

 Island in 2001. Nursing periods were calculated where birth and weaning

 dates were both known or occurred within a range of 4 days or less. All 

 measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm)

Straight dorsal

length (cm)

Mean 36.3 103.5 124.6

Standard

deviation

4.8 11.8 9.0

n 12 14 14
51

Table 4.5a.–Documented movement of Hawaiian monk seals to Lisianski Island from

 other locations in 2001, summarized by movements between 2 locations.

 Two seals made more than 1 observed trip.

Original location Number of trips, size, and sex class

Laysan Island 10 adult female

 2 subadult male

 1 subadult female

Table 4.5b.–Documented movement of Hawaiian monk seals from Lisianski Island to

 other locations in 2001, summarized by movements between 2 locations.

 Three seals made more than 1 observed trip.

Destination Number of trips, size, and sex class

Laysan Island 13 adult female

 2 subadult male

 1 subadult female

 1 juvenile female

Kure Atoll 1 subadult male 
52

Table 4.6.--Factors affecting Hawaiian monk seal survival at Lisianski Island in 2001.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Adult Male

Female

7

1

6

1

0

0

1

0

Subadult Male

Female

1

2

1

2

0

0

0

0

Juvenile Female 1 0 0 1

Mounting by Male

(none observed)

Entanglement

Adult Male

Female

1

a

1

a

0

0

0

0

0

0

Emaciation

Adult Male

Female

1

 

1

b

0

0

0

1

1

0

Juvenile Female 2

 0 1 1

Other/Unknown

Subadult Male 1 0 1 0

Juvenile Male 1 0 1 0

Nursing Pup Female

Unknown

1

2

0

0

1

1

0

1

a

 Seal released by observers.

b The adult female was emaciated post weaning, suffered 2 separate shark injuries, and 

 eventually died. 
53

CHAPTER 5. THE HAWAIIAN MONK SEAL ON 

PEARL AND HERMES REEF, 2001

Chad H. Yoshinaga, Raymond C. Boland, and Lizabeth S. Kashinski
1 ,"oJ ----

~~~ 

..' 

_.,.to , 

•• .....1 

./ot"",. ....... •

~J • - '

"j~' ' .. -­"l (I • ,. " ••!\ '. 

_ r' ... I.,' 

1'l.J ~"':.,J'""-

" .~ I p.' .'O

.•,~., ... ,.;. ~.' 

'. 't1 ,\, .......< 

. I."!:'~ 

...,.:.. .~'v~'

.....:",:;\'V'''-' ,>

,. /', • , ' 

r:. ~ .,.:. . . I J.'l.

_..' ...

1."- :;;;-r.. _••••• ..:•••'../". "', " ". 

'" ",. ,I, '., \.

,:''''''. ~. ­'\,,~ 

. -"., 

.:.. - .­~ -. "'("" 

,_.,~i..«",.. . ..., ~~. ," 

.' " 

,.,.,..,' 

. . ....~;'-!'" 

./-," ,'....

"\/ " •." ,

....­ .,' ~ " ~ ," '", 1\ ,\

-. ~. ',. ':" 

" . ." , . V'.": ;~,;..., ­ .::: .i'/':

' _.. . , .. ';" . : ,",1 :' 1...... ," Bl·rd"4lli:.~":····,' 

27°55' 

..c= 

+-I 

~ 

o 

Z 

Q 

"0

::s 

.-=: 50' +-I 

ccs 

~ 

45' 

o~\ 

\\0 '1> Pearl and Hermes ~'\):~ 

" ., .... ' ., Reef t)i "•• .;: ......4 

" .1of 

: .'. _ ••..:J. ...... 


d.' .' \.' ""'-! .._­

~\~~ •• '~" -'.. A~ .' )0 '" ' '.1

'T .. ' ' ... ,'". '.:.,':/" 

,••• ," \. ...." , ,.• , 0\'.' ' _ ,_ C..- ~ ,p.....,";""'\ . •. 

fI.!.'J ....':)~')...~ ~. ''"')(''\''i'\ :?\'/J;" .. " ,.,<.,/~ .,..0_ ., ~'.-o" ...... . ..- ~... '.. .~, \ ,. <:iJJ' ") .' .,'•...rJ........ 
 ......:'l"l. .... • .. (, I 111,·..,

.. ", . ~ I 

" ',', .t!)1 \ "", .," , """",, ," '" ,'., ..... ., ' .. , .' ......, ....., ,f.> v ,r. ..... ... .' ­ ,.. • ....:t.Il. _ ':\ • ' . • " ,'",. ' v\.. : ~1""';"" <.." . " .! .. ; '. 

...... .' ". .. " 

"'" ...::~ .ilf..r... ,~'"'lv.' • '. « ' ..:::.~ ,-' ._,. .... .. .. ~'''.' "I' .... 1" :...of :/)v • • .... .. -f. .,-,'

,~- ,,.,..' ,.... _ • I"" ,/ -;;-<,,--:.,'. 

•. _~~ t.? " ..... ~~' ~"',"'.. 

'.i. ' !." • ,"I"

• ~9' ,\.:." ,:'" .... ' "-k,'.. " r.," ~,' ......""... \ ,\"; ,i ,;' Sand


. " -:iii:,--..... = l. l. South,.,t
 ""\I' T.' " -~----- 

~ 'V Grass 1. I. 


55' 50' 

Longitude West 

Fig. 5.1 Pearl and Hermes Reef in the Northwestern Hawaiian Islands. 
55

Pearl and Hermes Reef (lat. 27°55'N, long. 175°45'W) is one of the primary

haulout and pupping locations of the Hawaiian monk seal. This atoll is located ca. 1,900

km northwest of Oahu in the Northwestern Hawaiian Islands and is part of the Hawaiian

Islands National Wildlife Refuge (Fig. 1.1). Pearl and Hermes is composed of 4 vegetated

and 3 nonvegetated sand islets enclosed in a fringing reef (Fig. 5.1).

RESEARCH

The National Marine Fisheries Service (NMFS) began research on Hawaiian

monk seals at Pearl and Hermes Reef in 1982. In 2001, research was conducted by

NMFS during April 15 and from May 20 to July 22. Incidental observations were

recorded by U.S. Fish and Wildlife Service (USFWS) personnel on August 11 and

October 3. The perimeters of the 4 larger vegetated islets were divided into sectors using

natural landmarks. Research activities specific to this subpopulation in 2001 included

opportunistic patrols of the emergent reef. 

Censuses and Patrols

Atoll censuses (n = 8) were conducted every fourth day, on average, from May 29

to July 5. Each atoll census began between 0937 and 1024 and ended between 1433 and

1607 Hawaii Standard Time. All islets were censused on foot by 1 or 2 persons. 

Incidental patrols were conducted opportunistically to resight seals tagged in previous

years and to identify and bleach-mark all animals in the subpopulation. In addition,

surveys of the emergent reef were conducted by boat and kayak to determine whether a

significant number of animals use these areas as haulout sites and should be surveyed on

a regular basis.

Individual Identification

A total of 249 individuals (217 excluding pups) were identified by existing or

applied tags, scars, or natural markings. Twenty-five weaned pups were tagged with

Temple Tags and passive integrated transponder (PIT) tags. In addition, a juvenile male

was newly tagged with Temple Tags and a PIT tag, and an adult female was retagged

with Temple Tags.

Collection of Samples

Forty scat and 1 spew samples were collected. Skin punches were collected from

23 weaned pups and from 2 other seals during tagging. Various epidemiological samples

were collected from 8 seals during the April-May health and disease study. In total, 24
56

items of potentially entangling debris were inventoried and stored for future removal by

ship.

Special Studies

Health and Disease

Under provisions of the Marine Mammal Protection Act of 1972, the Working

Group on Marine Mammal Unusual Mortality Events (UME) determined that a UME

involving juvenile Hawaiian monk seals was occurring at Laysan (see the Laysan Island

chapter). A team visited Pearl and Hermes Reef on April 15 and May 20-21 and collected

blood, fecal samples, virological and bacteriological swabs, and blubber biopsies from an

unhealthy juvenile male, 6 healthy juvenile seals (3 male and 3 female), and from an adult

female sampled incidental to a disentanglement.

Emergent Reef Surveys

In 2001, preliminary surveys were conducted to characterize seal haulout patterns

on the emergent reef and determine if a subset of the seals at Pearl and Hermes Reef were

hauling out solely on the barrier reef and not being observed on the islands. One boat

survey and 1 kayak survey were conducted to compare survey methods.

During both surveys seals were observed on the reef. Because of the shallow areas

surrounding the fringing reef, boats were unable to approach close enough to identify any

seals. Kayaks allowed for a closer inspection of the reef areas, and therefore produced a

more accurate count of seals hauled out and allowed for individual identification of 90%

of the animals sighted.

The majority of the seals sighted on the fringing reef were juvenile and subadult

animals. In the single kayak survey, 3 juvenile seals were observed that had not been

sighted elsewhere on land. In addition, 1 weaned pup was resighted that had been

bleached and not tagged, confirming its existence.

RESULTS

Subpopulation Abundance and Composition

The mean (±SD) of 8 atoll censuses was 100.1 seals (±8.6) including pups and

80.8 seals (±9.5) excluding pups (Table 5.1). The total summer subpopulation was 243

individuals, 211 excluding pups (Table 5.2). This number is a subset of the total

identified in the calendar year. The numbers of tagged known-age seals born at Pearl and

Hermes Reef during the period from 1983 to 2000, and resighted at any location in 2001,

are summarized in Table 5.3.
57

Reproduction

At least 32 pups were born at Pearl and Hermes Reef in 2001: 26 were

successfully weaned, 2 were found dead, and 4 were still nursing at the end of the

research period (Table 5.4). The birth rate, measured as the number of pups born divided

by the number of adult-sized females in the subpopulation X 100, was 44.4% ((32/72) X

100). Nursing periods and measurements of weaned pups are summarized in Table 5.4.

Interatoll Movement

Interatoll movement was documented for 18 seals that completed a total of 24

movements between Pearl and Hermes Reef and either Laysan Island, Midway Atoll, or

Kure Atoll (Tables 5.5a and b). 

Factors Affecting Survival

Entanglement in marine debris and unknown factors resulted in 8 life-threatening

conditions (Table 5.6). During 2001, 3 juvenile seals were found dead (1 male and 2

females). One was discovered during the first patrol of Seal Kittery, another was found on

Peanut during the middle of the season, and the third was found in August on Southeast

after the main field season. All carcasses were found too decomposed to necropsy. In

addition, 2 pups were found dead at the beginning of the season. Both were small pups, 1

with its umbilicus still attached. One adult female and 1 juvenile male were disentangled

from debris. The adult female sustained lacerations around her neck. All wounds were

observed healed later in the season. One subadult female seal was observed with a large

gaping wound on the side of her head. The wound was observed healing throughout the

season. In addition to the incidents presented in Table 5.6, 1 subadult and 2 adult seals

were observed with unilateral clouded eyes, and 2 juveniles (a male and female) were

emaciated in October, after the main field season. 

ACKNOWLEDGMENTS

We thank the captain, officers, and crew of the NOAA Ship Townsend Cromwell. 

We also acknowledge the support of the U.S. Fish and Wildlife Service, Hawaiian Islands

National Wildlife Refuge staff.

59

TABLES

for Pearl and Hermes Reef

61

Table 5.1.--Summary statistics for atoll censuses (n =8) of the Hawaiian monk seal at

 Pearl and Hermes Reef from May 29 to July 5, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 57.0 6.0

Male 21.1 3.9

Female 28.8 3.1

Unknown 7.1 2.0

Subadults 9.9 3.6

Male 4.0 2.3

Female 4.4 1.9

Unknown 1.5 1.7

Juveniles 13.3 2.5

Male 5.9 1.6

Female 6.8 1.2

Unknown 0.6 0.9

Pups 19.4 2.3

Male 11.9 2.0

Female 6.5 1.4

Unknown 1.0 1.2

Non-pup total 80.8 a 9.5

Grand total 100.1 a8.6

a

 Total includes some seals which were not placed in any size class.
62

Table 5.2.--Composition of the Hawaiian monk seal subpopulation at Pearl and Hermes

 Reef during the spring and summer of 2001. Includes all known parturient

 females and pups born during the calendar year. 

Number of seals

Size Male Female Unknown Total

Sex ratio

male:female

Adults 63 72 0 135 0.9:1

Subadults 14 19 0 33 0.7:1

Juveniles 21 22 0 43 1.0:1

Pups 18 10 4 32 1.8:1

Non-pup total 98 113 0 211 0.9:1

Grand total 116 123 4 243 0.9:1
63

Table 5.3.--Summary of tagged known-age seals born at Pearl and Hermes Reef and

 resighted at any location in 2001.

Cohort year

Age

(years) Sex

Number

originally tagged

Number

resighted 

in 2001

1983 18 Male

Female

8

2

1

1

1984 17 Male

Female

5

8

1

3

1985 16 Male

Female

9

6

2

3

1986 15 Male

Female

Unknown

10

7

1

2

2

0

1987 14 Male

Female

14

7

5

3

1988 13 Male

Female

12

6

6

4

1989 12 Male

Female

8

6

3

2

1990 11 Male

Female

5

1

3

0

1991 10 Male

Female

10

11

7

6

1992 9 Male

Female

13

10

7

8

1993 8 Male

Female

14

7

5

4

1994 7 Male

Female

--

--

–

--

1995 6 Male

Female

15

12

5

5

1996 5 Male

Female

11

12

2

5

1997 4 Male

Female

16

11

8

6

1998 3 Male

Female

8

21

3

16

1999 2 Male

Female

11

15

8

8

2000 1 Male

Female

12

10

10

 6
64

Table 5.4a.--Summary of Hawaiian monk seals born at Pearl and Hermes Reef in 2001.

Event

Number of pups

Male Female Unknown Total

Born 18 10 4 32

Died prior to weaning 0 0 2 2

Still nursing 1 1 2 4

Weaned 17 9 0 26

Tagged 16 9 0 25

Table 5.4b.--Summary of nursing periods and measurements of weaned pups at Pearl and

 Hermes Reef in 2001. Nursing periods were calculated where birth and

 weaning dates were both known or occurred within a range of 4 days or less. 

 All measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm)

Straight dorsal length

(cm)

Mean 35.4 105.7 124.9

Standard

deviation

6.4 8.3 7.0

n 5 15 16
65

Table 5.5a.–Documented movement of Hawaiian monk seals to Pearl and Hermes Reef

 from other locations in 2001, summarized by movements between 2

 locations. No seals made more than 1 observed trip.

Original location Number of trips, size, and sex class

Laysan Island 1 juvenile male

Midway Atoll 2 adult male 

6 adult female

Kure Atoll 1 adult female 

Table 5.5b.–Documented movement of Hawaiian monk seals from Pearl and Hermes

 Reef to other locations in 2001, summarized by movements between 2

 locations. One seal made more than 1 observed trip.

Destination Number of trips, size, and sex class

Laysan Island 1 subadult female

Midway Atoll 4 adult male

6 adult female

1 weaned pup male

Kure Atoll 1 adult female 

1 subadult male
66

Table 5.6.--Factors affecting Hawaiian monk seal survival at Pearl and Hermes Reef in

 2001.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

(none observed)

Mounting by Males

(none observed)

Entanglement

Adult Female 1

a

1 0 0

Juvenile Male 1

a

0 0 0

Unknown

Subadult Female 1 1 0 0

Juvenile Male

Female

1

2

0

0

1

2

0

0

Nursing pup Unknown 2 0 2 0

aSeal released by observers.
67

CHAPTER 6. THE HAWAIIAN MONK SEAL ON

MIDWAY ATOLL, 2001

Bruce R. Casler, Andrea D. Shluker, Patti A. Haase
16' 

Midway Atoll 

2 km N ~ -+-l 

~ 

o )) 

00 

Z 14' o o 

"C 

=' -+-l

o?""4 

-+-l 

~ 

~ 

28 °12' 

Longitude West 

Fig. 6.1 Midway Atoll in the Northwestern Hawaiian Islands. 

24' 

69

Midway Atoll (lat. 28°14'N, long. 177°22'W) is one of the primary haulout and

pupping locations of the endangered Hawaiian monk seal. This atoll is located ca. 2,100

km northwest of Oahu in the Northwestern Hawaiian Islands (Fig. 1.1) and comprises a

circular atoll approximately 9 km in diameter, enclosing a lagoon and 3 permanent islets

inside the southern part of the reef (Fig. 6.1). Eastern and Spit are uninhabited. Sand

Island was the site of a U.S. Naval Air base from ca. 1939 until 1993. The U.S. Fish and

Wildlife Service (USFWS) had maintained an overlay refuge (Midway Atoll National

Wildlife Refuge) at the site since 1988 until full authority was transferred to the USFWS

in October 1996. In 1996, USFWS joined Midway Phoenix Corporation (MPC) in a

cooperative agreement. Through this agreement MPC maintained the infrastructure and

operated the airport and harbor. Additionally, this agreement enabled MPC to operate

ecotourism and recreational ventures.

Beach counts of the Hawaiian monk seal at Midway Atoll averaged 56 animals in

the late 1950s (Kenyon, 1972) but declined severely by the late 1960s; a single seal was

observed during an aerial survey in 1968 (Kenyon, 1972). Currently, recovery is

underway because of immigration from nearby Kure Atoll and Pearl and Hermes Reef

and an increasing number of seals born on Midway Atoll. Recovery of this subpopulation

remains an important management goal (Gilmartin and Antonelis, 1998).

RESEARCH

The National Marine Fisheries Service (NMFS) began limited monitoring of

Hawaiian monk seals at Midway Atoll in 1983. This effort was increased to year-round

monitoring in 1997 in collaboration with researchers from Oceanic Society (OS) and

Hawaii Wildlife Fund (HWF). HWF concluded its year-around monitoring program in

January 2000, and research continued through a contract agreement between NMFS and

USFWS from February to September 2000. In 2001, research was conducted by NMFS

from January 1 to January 6 and February 25 to September 4. Incidental observations of

seals, disturbance monitoring of public beaches, and public education lectures were

conducted by USFWS and OS personnel throughout the year. 

Perimeters of the 3 permanent islets were divided into sectors using artificial or

natural landmarks. Research activities specific to this subpopulation in 2001 included (1)

beach counts and monitoring; (2) emergent reef surveys to determine haulout patterns in

these areas; (3) satellite tag deployment for a foraging ecology study, with blood and 

tissue sampling for health assessment purposes taking place at the same time; (4) survey

for and removal of marine debris from the north and east reef flats, emergent reef areas,

and all beaches; and (5) monitoring human impacts on seals to quantify occurrence and

potential effects on monk seal habitat usage. 
70

Censuses and Patrols

Atoll censuses (n = 25 ) were conducted every seventh day, on average, from

March 7 to August 29. Each atoll census began between 0726 and 1650, and ended

between 1000 and 1740 Hawaii Standard Time. All islets were censused on foot by 1 or 2

persons. Patrols of Sand Island (n = 57), Eastern (n = 60), or Spit (n = 50) were conducted

on nonatoll census days during January 10-September 4. 

Individual Identification

A total of 81 individuals (66 excluding pups) were identified by existing or

applied tags, bleach marks, scars, or natural markings. Eleven weaned pups were tagged

with Temple tags and passive integrated transponder (PIT) tags. One pup that disappeared

shortly after birth was not tagged. During the satellite telemetry study, an adult female

was newly tagged with Temple Tags and a PIT tag, 2 adult males were retagged with

Temple tags and PIT tags, and 2 subadults were retagged with Temple tags (a male and

female).

Collection of Samples

Skin punches were collected from 11 weaned pups during tagging. Three spews,

55 scats, and 27 shed molt samples were also collected. One necropsy was performed and

tissue samples were taken. Blood, fecal, and tissue samples were collected from 16 seals

during the satellite telemetry project in January and from 2 seals during the health and

disease study in May. Four hundred eighteen items of potentially entangling marine

debris totaling approximately 2,514 kg were collected by NMFS and OS personnel and

were either destroyed at Midway or stored on Midway for removal by NOAA or Coast

Guard ships. USFWS also conducted a marine debris removal program with staff and

volunteers and collected an unknown number of lines and nets totaling 6,375 kg, bringing

the total amount of debris removed at Midway from January through August to 8,889 kg.

Special Studies

Foraging Ecology, Health, and Disease

In January 2001, researchers from NMFS, Hubbs-Sea World Research Institute

and Sea World of Texas began a study on movements and foraging behavior of Hawaiian

monk seals at Midway. Sixteen seals (4 adult, 6 subadult, and 6 juveniles) were outfitted

with satellite-linked dive recorders that collect data on diving patterns and geographic

locations for each seal. During the restraint of these seals, blood and tissue samples were

taken for health assessment purposes. Assistance for this project was also provided by

USFWS. 
71

Under provisions of the Marine Mammal Protection Act of 1972, the Working

Group on Marine Mammal Unusual Mortality Events (UME) determined that a UME

involving juvenile Hawaiian monk seals was occurring at Laysan (see the Laysan Island

chapter). A team visited Midway Atoll on May 11-16 and collected blood, fecal samples,

virological and bacteriological swabs, and blubber biopsies from 2 unhealthy juvenile

males.

Emergent Reef Surveys

Patrols were conducted 1-2 times per week, depending on weather conditions,

along the emergent reef areas of the North Reef (n = 28) and East Reef (n = 28) from

January 29 to August 30. Two people using kayaks and a motorboat surveyed the reefs for

seals and turtles. On 15 occasions, both emergent reef areas were surveyed within 1 day

of atoll counts to provide an estimate of atoll-wide beach/emergent reef counts.

Noteworthy Events

Beach Monitoring and Public Education

During 2001, Sand Island beaches and trails were monitored for potential monk

seal disturbance and refuge violations. Most of the disturbance monitoring took place in

public use areas, but information about potential disturbance was also collected during

standard monk seal surveys of Sand Island’s closed beaches. A minimum of 2 disturbance

patrols were conducted every day (morning and evening), with more being done as

needed, depending on the presence and locations of seals. In all, from January 1 to

August 31, 437 hours were spent conducting 421disturbance patrols, and 252 hours were

spent conducting 82 standard monk seal censuses. 

Other actions taken during the field season to help mitigate disturbance to seals at

Midway and support the desire of USFWS to maintain “visitor friendly” directives

included the continuation of the “red seal” sign system, alerting residents and guests of a

seal’s presence in public-use areas on Sand Island. These signs were put in place near

resting seals 255 times. 

Informational lectures were presented weekly to island residents, visiting students

and researchers, and general visitors. Topics covered included monk seal natural history,

current information about Midway’s subpopulation, NMFS recovery efforts and recovery

team priorities, and the reasons for refuge rules governing seal viewing and beach

closures.
72

RESULTS

Subpopulation Abundance and Composition

The mean (+SD) of 25 atoll censuses was 23.4 seals (+4.9) including pups, and

18.7 seals (+5.1) excluding pups (Table 6.1). The total spring-summer subpopulation was

67 seals, 55 excluding pups (Table 6.2). This number is a subset of the total identified in

the calendar year. The numbers of tagged known-age seals born at Midway Atoll during

the period from 1988 to 2000, and resighted at any location in 2001, are summarized in

Table 6.3.

Reproduction

A minimum of 12 pups were born at Midway Atoll in 2001, 11 successfully

weaned, and 1 disappeared within 3 days after being born, and probably died (Table

6.4a). The birth rate, measured as the number of pups born divided by the number of

adult-sized females in the subpopulation X 100 was 52.2% ((12/23) X 100). No pup

exchanges occurred between nursing females. Nursing periods and measurements of

weaned pups are summarized in Table 6.4b.

Interatoll Movement

Interatoll movement was documented for 34 seals that completed 59 movements

between Midway Atoll and either Pearl and Hermes Reef or Kure Atoll (Tables 6.5a and

b).

Factors Affecting Survival

Attacks by sharks, entanglement in marine debris, emaciation, and other/unknown

causes led to 12 life-threatening conditions, which resulted in the confirmed death of 1

seal and the probable death of 4 other seals (Table 6.6). One very thin juvenile female

was found dead of unknown causes on Eastern Island and 3 emaciated/very thin juveniles

disappeared (2 of which displayed signs of ill health prior to death). One pup disappeared

shortly after being born on Spit Island and was never seen again. Two seals were

entangled in marine debris and were freed by researchers: a recently weaned female pup

who had an eel trap cone around her muzzle and an adult female that became entangled in

a line and trawl net. In addition to the incidents listed in table 6.6, 2 seals showed signs of

ill health but later regained normal behavior patterns. In addition, 3 emaciated weaned

pups were sighted in the fall, and 2 were not subsequently resighted.
73

ACKNOWLEDGMENTS

We acknowledge the support of the U.S. Fish and Wildlife Service, Oceanic

Society, and Midway Phoenix Corporation. Special thanks are extended Nancy Hoffman,

Refuge Biologist; Stephanie Bennett and Joe Raffaele, USFWS Rangers; Wayne Sentman

and Cynthia Vanderlip, OS staff; and the Midway Harbor crew. We also thank the

officers and crew of the NOAA ship Townsend Cromwell for logistical assistance. 

75

TABLES

for Midway Atoll

77

Table 6.1.--Summary statistics for atoll censuses (n = 25) of Hawaiian monk seals at

 Midway Atoll from March 7 to August 29, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 10.2 3.2

Male 2.0 1.2

Female 7.5 2.7

Unknown 0.6 1.3

Subadults 5.1 2.1

Male 2.3 1.3

Female 2.7 1.2

Unknown 0.2 0.4

Juveniles 3.4 2.3

Male 2.4 1.4

Female 0.9 1.1

Unknown 0.2 0.5

Pups 4.7 2.5

Male 2.7 1.7

Female 1.8 1.1

Unknown 0.3 0.5

Non-pup total 18.7 5.1

Grand total 23.4 4.9
78

Table 6.2.--Composition of the Hawaiian monk seal subpopulation at Midway Atoll

during the spring and summer of 2001. Includes all known parturient females

and pups born during the calendar year.

Number of seals

Size Male Female Unknown Total

Sex ratio

male:female

Adults 10 23 0 33 0.4:1

Subadults 5 6 0 11 0.8:1

Juveniles 6 5 0 11 1.2:1

Pups 6 5 1 12 1.2:1

Non-pup total 21 34 0 55 0.6:1

Grand total 27 39 1 67 0.7:1
79

Table 6.3.--Summary of tagged known-age seals born at Midway Atoll and resighted at

 any location in 2001.

Cohort year

Age

(years) Sex

Number

originally

tagged

Number

resighted 

in 2001

1988 13 Male

Female

0

1

NA

1

1989 12 Male

Female

0

0

NA

NA

1990 11 Male

Female

0

0

NA

NA

1991 10 Male

Female

1

1

1

1

1992 9 Male

Female

0

1

NA

1

1993 8 Male

Female

1

0

0

NA

1994 7 Male

Female

0

0

NA

NA

1995 6 Male

Female

Unknown

1

6

1

0

1

0

1996 5 Male

Female

1

4

0

0

1997 4 Male

Female

3

6

1

3

1998 3 Male

Female

8

2

3

2

1999 2 Male

Female

7

4

3

1

2000 1 Male

Female

5

9

4

3
80

Table 6.4a.--Summary of Hawaiian monk seals born at Midway Atoll in 2001.

Event

Number of pups

Male Female Unk. Total

Born 6 5 1 12

Probably died prior to weaning 0 0 1 1

Weaned 6 5 0 11

Tagged 6 5 0 11

Table 6.4b.--Summary of nursing periods and measurements of weaned pups at Midway

 Atoll in 2001. Nursing periods were calculated where birth and weaning

 dates were both known or occurred within a range of 4 days or less. All

 measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm)

Straight dorsal

length (cm)

Mean 38.1 114.7 127.9

Standard

deviation

3.6 7.8 4.7

n 11 11 11
81

Table 6.5a.–Documented movement of Hawaiian monk seals to Midway Atoll from other

 locations in 2001, summarized by movements between 2 locations. Four

 seals made more than 1 observed trip.

Destination Number of trips, size, and sex class

Pearl and Hermes Reef 4 adult male 

6 adult female

1 weaned pup male

Kure Atoll 3 adult male 

12 adult female 

 2 subadult male

1 weaned pup male

1 weaned pup female

Table 6.5b.–Documented movement of Hawaiian monk seals from Midway Atoll to other

 locations in 2001, summarized by movements between 2 locations. Five

 seals made more than 1 observed trip.

Destination Number of trips, size, and sex class

Pearl and Hermes Reef 2 adult male

 6 adult female

Kure Atoll 3 adult male 

13 adult female 

 2 subadult male

 1 juvenile male 

 1 weaned pup male

 1 weaned pup female
82

Table 6.6.--Factors affecting Hawaiian monk seal survival at Midway Atoll in 2001.

Outcome

Size Sex Total Injured Died

Probably

died

Attack by Large Shark

Adult Female 2 2 0 0

Juvenile Male 2 2 0 0

Mounting by Males

(none observed)

Entanglement

Adult Female 1

a

0 0 0

Weaned pup Female 1

a

0 0 0

Emaciation

Juvenile Male

Female

1

3

0

0

0

1

b

1

2

c 

Other/Unknown

Subadult Female 1 1 0 0

Nursing pup Unknown 1 0 0 1

aSeal released by researchers.

bSeal was also considered ill, found dead on Eastern, necropsy completed, cause of death

 unknown.

cOne of the females was also considered ill, became thin, began displaying unusual

 behaviors, then was never seen again.
83

CHAPTER 7. THE HAWAIIAN MONK SEAL ON

KURE ATOLL, 2001

Patti A. Haase and Albert L. Harting
Kure Atoll 

..r:: 

-+-I 

f...4 26' 


0 


Z 

l1.) Stark 

"0 ~ 

I. 

::s 

-+-I 

I .:J .­-+-I 

c::s \1 ~ N 

28°24' ~ t Sand 1. 


"'\.., , , .r-­

2 km 

178°22' 20' 18' 

Longitude West 

Fig. 7.1 Kure Atoll in the Northwestern Hawaiian Islands. 
85

Kure Atoll (lat. 28°25'N, long. 178°10'W) is one of the primary haulout and

pupping locations of the Hawaiian monk seal. The atoll is located ca. 2,300 km northwest

of Oahu in the Northwestern Hawaiian Islands (Fig. 1.1) and is a seabird sanctuary of the

State of Hawaii. The atoll consists of a circular barrier reef approximately 9 km in

diameter, the enclosed lagoon, 1 permanent vegetated island (Green Island), 2 sand islets

(Sand and Shark), and an ephemerally emergent area known locally as Stark Reef (Fig.

7.1). From 1960 to 1992, Green Island was the site of a U.S. Coast Guard (USCG)

LORAN station, staffed by 20-30 USCG personnel. In July 1992, this station was closed

and vacated by the USCG, leaving the atoll uninhabited. In 1993, the USCG completed

the removal of most of the infrastructure on Green Island. 

The Kure Atoll subpopulation of Hawaiian monk seals has increased in recent

years due, apparently in part, to a reduction of human disturbance and a capture and

release program designed to increase recruitment of females. The Rehabilitation Project

(1984-91, 1993-95) involved the capture of undersized weaned female pups from French

Frigate Shoals, their rehabilitation on Oahu, and subsequent transport to Kure Atoll for

release. 

RESEARCH

National Marine Fisheries Service (NMFS) began research on the Hawaiian monk

seal at Kure Atoll in 1981. In 2001, research was conducted by NMFS on April 11, from

May 18 to July 18, and from October 30 to November 13. The perimeter of Green Island

was divided into 8 sectors using artificial or natural landmarks. Research objectives

specific to this subpopulation in 2001 included (1) identification of all seals using the

atoll, and (2) assessing entanglement risks and other negative impacts following the

Paradise Queen II’s grounding at Kure Atoll on October 16, 1998.

Censuses and Patrols

Atoll censuses (n = 12) were conducted every fourth day on average, from May 25

to July 10. Each census began between 1237 and 1350 and ended between 1527 and 1755

Hawaii Standard Time. All islets were censused on foot by 1 or 2 persons. Shark Islet and

Stark Reef were not emergent during the 2001 field season. Patrols were conducted on

nonatoll census days to identify seals and monitor locations used by parturient females. In

total, 15 patrols of Green Island and 1 patrol of Sand Islet were conducted. 

Individual Identification

A total of 127 individuals (107, excluding pups) were identified by existing or

applied tags, bleach marks, scars, or natural markings. All weaned pups (n = 17) were
86

tagged with Temple Tags, and passive integrated transponder (PIT) tags. One female pup

was still nursing at the end of the field season and was not resighted during the autumn

camp, so she was not tagged. Three seals (an adult male, a juvenile female, and a knownage juvenile male born at Kure in 1998) were newly tagged with Temple Tags, and the

juvenile female also received a PIT tag. In addition, 4 adult seals (3 males and a female)

were retagged with Temple Tags in 2001.

Collection of Samples

Sixteen scat samples were collected. Skin punches were collected from 18 seals

during tagging. Various epidemiological samples were collected from 2 seals during the

health and disease study in May, and from 24 seals during the satellite tagging project in

October and November. In total, 299 items of potentially entangling marine debris were

inventoried. Two large net aggregates remain partially buried on Green Island on the

southeast side. The remainder of inventoried debris items were destroyed before the end

of the field season or securely stored for later removal.

Special Studies

Foraging Ecology, Health, and Disease

Under provisions of the Marine Mammal Protection Act of 1972, the Working

Group on Marine Mammal Unusual Mortality Events (UME) determined that a UME

involving juvenile Hawaiian monk seals was occurring at Laysan (see the Laysan Island

chapter). A team visited Kure Atoll on May 18 and collected blood, fecal samples,

virological and bacteriological swabs, and blubber biopsies from 2 healthy juveniles (1

male and 1 female). 

During October-November 2001, a field camp was deployed (1) to attach satellitelinked dive recorders (SLDRs) in order to characterize at-sea habitat use, (2) to collect

epidemiological sampled (blood, swabs, blubber, etc.) for health and disease assessment,

and (3) to retag or newly tag seals to facilitate individual identification in the

subpopulation. A total of 27 seals were handled. Twenty-four seals were fully sampled

for the health and disease assessment and received SLDRs.

Noteworthy Events

Impacts of Paradise Queen II Grounding

On October 16, 1998, the Paradise Queen II, a lobster fishing vessel, ran aground

on the eastern edge of Kure Atoll. In 2000, a large portion of the hull remained in the

water on the reef, but remnants of the wheelhouse and 1 other structural piece had washed

ashore on the eastern side of Green Island. In 2001, the wheelhouse remained on the
87

eastern side of the island, and 1 other structural piece rested on the beach on the western

side (sector 1). The large portion of main deck which originally migrated around the

island from the west side (sector 1; in 1999) to the southwest point (sector 6; in 2000)

was not seen in 2001. Almost all previously collected traps were removed from Green

Island during a multiagency cleanup effort in October 2000, and only 15 traps were

collected in 2001. A few of these were destroyed but the majority remain stored on the

island. Some of the lead (used to weigh traps) still remain on the island. It is unknown

whether any lobster traps remain in the waters off Kure Atoll.

RESULTS

Subpopulation Abundance and Composition

The mean (±SD) of 12 atoll censuses was 53.4 seals (±9.2) including pups, and

45.2 seals (±6.7) excluding pups (Table 7.1). The total spring-summer subpopulation was

118 individuals, 100 excluding pups (Table 7.2). This number is a subset of the total

identified in the calendar year. The numbers of tagged known-age seals born at Kure

Atoll during the period from 1981 to 2000, and resighted at any location in 2001, are

summarized in Table 7.3.

Reproduction

At least 18 pups were born at Kure Atoll in 2001, and 17 successfully weaned

(Table 7.4a). One pup was still nursing at the end of the study period. Nursing periods

and measurements of weaned pups are summarized in Table 7.4b.) The birth rate,

measured as the number of pups born divided by the number of adult-sized females in the

subpopulation X 100 was 45.0% (18/40) X 100). Nine of 10 identified parturient females

(90.0%) were involved in past management efforts; 6 had been temporarily maintained as

pups in the Kure Atoll Head Start enclosure (1 each in 1984 and 1991, and 2 each in 1985

and 1988), and 3 were rehabilitated seals from FFS introduced to Kure as yearlings via

the Head Start enclosure (1 each released in 1990, 1993, and 1995).

Interatoll Movement

Interatoll movement was documented for 25 seals that completed a total of 44

movements between Kure Atoll and either Lisianski, Pearl and Hermes Reef, or Midway

Atoll (Table 7.5a and b).

Factors Affecting Survival

Attacks by large sharks and entanglement in marine debris led to 3 lifethreatening conditions. An adult female and a male weaned pup were injured by a large
88

shark. Another male weaned pup became entangled and was subsequently released by

observers. No dead seals were observed during 2001 (Table 7.6).

ACKNOWLEDGMENTS

We acknowledge the support of the State of Hawaii, Department of Land and

Natural Resources (DLNR), Division of Forestry and Wildlife (DoFAW), and Leo Milan

for assistance at Kure Atoll. We also thank the captain and crew of the NOAA ship

Townsend Cromwell for logistical support and transport to and from the island.
89

TABLES

for Kure Atoll

91

Table 7.1.–Summary statistics for atoll censuses (n = 12) of Hawaiian monk seals at Kure

Atoll from May 25 to July 10, 2001.

Size/Sex Mean number of individuals Standard deviation

Adults 35.3 5.1

Male 13.3 3.4

Female 17.8 4.0

Unknown 4.2 2.7

Subadults 6.5 2.5

Male 3.4 1.5

Female 2.2 0.8

Unknown 0.9 1.0

Juveniles 3.4 1.4

Male 1.6 0.9

Female 1.7 0.9

Unknown 0.2 0.4

Pups 8.3 3.6

Male 1.2 1.1

Female 4.4 2.0

Unknown 2.7 2.7

Non-pup total 45.2 6.7

Grand total 53.4 9.2
92

Table 7.2.–Composition of the Hawaiian monk seal subpopulation at Kure Atoll during 

the spring and summer of 2001. Includes all known parturient females and

pups born during the calendar year.

Number of seals

Size Male Female Total

Sex ratio

male:female

Adults 32 40a 72 0.8:1

Subadults 10 6 16 1.7:1

Juveniles 6 6 12 1.0:1

Pups 4 14 18b0.3:1

Non-pup total 48 52 100 0.9:1

Grand total 52 66 118 0.8:1

a

 Number includes 25 individuals involved in management programs (Head Start, 

 Rehabilitation, and Translocation).

b

 Number includes 4 prematurely weaned female pups and 1 prematurely weaned male 

 pup.
93

Table 7.3.–Summary of tagged known-age seals born at Kure Atoll and resighted at any 

location in 2001.

Cohort year

Age

(years) Sex

Numb er originally

tagged

Number resighted

in 2001

1981 20 Male

Female

3

5

2

0

1982 19 Male

Female

1

3

0

2

1983 18 Male

Female

4

0

3

NA

1984 17 Male

Female

4

2

0

2

1985 16 Male

Female

2

3

1

2

1986 15 Male

Female

1

0

0

NA

1987 14 Male

Female

1

3

1

3

a

1988 13 Male

Female

2

5

2

2

1989 12 Male

Female

5

4

1

1

1990 11 Male

Female

3

3

0

1

1991 10 Male

Female

7

6

4

3

a

1992 9 Male

Female

5

8

3

5

1993 8 Male

Female

9

4

5

2

1994 7 Male

Female

3

0

0

NA

1995 6 Male

Female

6

5

4

2

1996 5 Male

Female

10

6

4

0

1997 4 Male

Female

9

7

1

3

1998 3 Male

Female

17

6

7

3

1999 2 Male

Female

8

13

2

6

2000 1 Male

Female

5

8

2

0

a Cohort survivors include se als removed from K ure Atoll for rehabilitation. These seals (n = 2) were

 released at K ure or M idway Atoll.
94

Table 7.4a.–Summary of Hawaiian monk seals born at Kure Atoll in 2001.

Event

Number of pups

Male Female Total

Born 4 14 18

Died prior to weaning 0 0 0

Still nursing 0 1 1

Weaned 4 13 17a

Tagged 4 13 17

a

 Number includes 4 prematurely weaned female pups and 1 prematurely weaned male 

 pup.

Table 7.4b.–Summary of nursing periods and measurements of weaned pups at Kure

 Atoll in 2001. Nursing periods were calculated where birth and weaning

 dates were both known or occurred within a range of 4 days or less. All

 measurements were taken within 2 weeks after weaning. 

Nursing period (d)

Axillary girth

(cm)

Straight dorsal

length (cm)

Mean 33.0 111.2 128.3

Standard deviation -- 6.8 3.6

n 1 5 5
95

Table 7.5a.–Documented movement of Hawaiian monk seals to Kure Atoll from other 

 locations in 2001, summarized by movements between 2 locations. Five

 seals made more than 1 observed trip.

Original location Number of trips, size, and sex class

Lisianski Island 1 subadult male

Pearl and Hermes Reef 1 adult female

 1 subadult male

Midway Atoll 3 adult male 

13 adult female 

 2 subadult male

 1 juvenile male

 1 male weaned pup

 1 female weaned pup

Table 7.5b.–Documented movement of Hawaiian monk seals from Kure Atoll to other

 locations in 2001, summarized by movements between 2 locations. Three

 seals made more than 1 observed trip.

Destination Number of trips, size, and sex class

Pearl and Hermes Reef 1 adult female

Midway Atoll 3 adult male 

12 adult female 

 2 subadult male

 1 male weaned pup

 1 female weaned pup
96

Table 7.6.–Factors affecting Hawaiian monk seal survival at Kure Atoll in 2001.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Adult Female 1 1 0 0

Weaned pup Male 1 1 0 0

Mounting by Males

(none observed)

Entanglement

Weaned pup Male 1

a

1 0 0

a

 Seal was released by observers.
97

CHAPTER 8. THE HAWAIIAN MONK SEAL ON

NIHOA AND NECKER ISLANDS, GARDNER PINNACLES, AND MARO REEF, 

2001

Dorothy M. Dick, Jacqueline M. Pearson, 

and Alexander S. Wegmann
98 


Pinnacle' 

Peak 

,.,..... 

Aaam's Bay 

Contours in feet 

N ihoa Island 0.25 km 

Necker Island N

West 

Cove 

/' .' Brown Peak 

I 

0.25 tm 

Contours in feet 

Summit Hill 

Fig. 8.1 Nihoa and Necker Islands in the Northwestern Hawaiian Islands. 
99

Nihoa Island (lat. 23°04'N, long. 161°55'W), Necker Island (lat. 23°36'N, long.

164°42'W), Gardner Pinnacles (lat. 25°00'N, long. 167°55'W), and Maro Reef (lat.

25°25'N, long. 170°35'W) are located in the Northwestern Hawaiian Islands (Fig. 1.1) and

lie within the Hawaiian Islands National Wildlife Refuge. 

RESEARCH

In 2001, the National Marine Fisheries Service collected data at Nihoa Island on

July 31, at Necker Island on July 30, and at Gardner Pinnacles on July 28. Additional data

were collected by U.S. Fish and Wildlife Service personnel at Nihoa Island on August 30,

at Necker Island on September 1-2, at Gardner Pinnacles on September 7, and at Maro

Reef on August 20. The perimeters of Nihoa and Necker Islands were divided into 3 and

10 sectors, respectively, using natural landmarks (Fig. 8.1). Gardner Pinnacles was

considered one sector. In 2001, research objectives specific to Nihoa and Necker Islands,

and Gardner Pinnacles included assessment of pup production and the extent of migration

between French Frigate Shoals and these locations.

Censuses and Patrols

Due to rough seas, a beach count was not conducted on Nihoa Island on July 31. 

However, a boat survey from the NOAA ship Townsend Cromwell was conducted along

the south facing shore of the island beginning at 1033 Hawaii Standard Time and

continuing for approximately 30 minutes. A beach count was conducted by 1 observer on

August 30, beginning at 0923 Hawaii Standard Time and continuing for 5.8 h.

Three beach counts were conducted on Necker Island on July 30 and on

September 1-2 by 2 and 1 observers, respectively. Censuses began between 0732 and

0820 Hawaii Standard Time and continued for 3.5 - 5.5 h. No boat surveys were

conducted.

Two boat surveys were conducted at Gardner Pinnacles on July 28 and

September 7 by 2 and 1 observers, respectively. Censuses began between 1023 and 1347

Hawaii Standard Time and continued for approximately 0.75 h.

No surveys were conducted at Maro Reef. However, incidental seal sightings

were noted by USFWS personnel on August 20. 
100

Individual Identification

On Nihoa Island, none of the seals sighted were identifiable by natural markings,

scars, or tags during either of the surveys.

On July 30, an adult female with broken French Frigate Shoals tags was seen on

Necker Island. The tags indicate the seal was 15 years old but further identification was

not possible. No other seals appeared tagged. During September 1-2, at least 3 adult seals

(unknown sex) were noted with French Frigate Shoals tags; no further identification was

possible. 

On July 28, an adult male was noted with a French Frigate Shoals tag at Gardner

Pinnacles. No further identification was possible. During September 7, none of the seals

seen were identified. 

On Maro Reef, 1 Laysan tagged weaned pup was sighted and identified.

Collection of Samples

No samples were collected at Nihoa Island, Necker Island, Gardner Pinnacles, or

Maro Reef in 2001.

RESULTS

Subpopulation Abundance and Composition

One partial island count at Nihoa Island on July 31 noted 3 seals (no pups

observed). The census total for complete count conducted on Nihoa Island was 9 seals (no

pups observed) on August 30. Because of limited effort, the composition of the springsummer subpopulation was not determined. 

The census totals for 3 counts conducted on Necker Island were 11 seals (10

excluding pups) on July 30, 13 seals (12 excluding pups) on September 1, and 22 seals

(20 excluding pups) on September 2. The mean of these counts is 15.3 (+ 5.9 SD)

including pups and 14.0 (+ 5.3 SD) excluding pups. Because of limited effort, the

composition of the spring-summer subpopulation was not determined.

The census totals for 2 counts conducted at Gardner Pinnacles were 5 seals (no

pups observed) on July 28 and 3 seals (no pups observed) on September 7. Because of the

limited effort, the composition of the spring-summer subpopulation was not determined.

No census totals were calculated for Maro Reef since the seal sighting was

incidental to other USFWS objectives. 
101

Reproduction

No pups were observed at Nihoa in 2001. At least 3 pups were born at Necker in

2001; 1 female pup was successfully weaned, and 2 were still nursing (both of unknown

sex). No pups were observed at Gardner Pinnacles in 2001. One weaned pup was

observed at Maro Reef in 2001, but this tagged pup was born at Laysan.

Interatoll Movement

Interatoll movement was documented for 2 seals; a weaned male pup, born and

tagged at Laysan Island in 2001 was subsequently observed at Maro Reef and an adult

female identified at Necker Island in 2000 was observed at French Frigate Shoals in 2001. 

The interatoll movement of tagged seals observed at Necker Island and Gardner Pinnacles

in 2001 could not be determined since these seals were unidentified. Interatoll movement

was not documented for seals observed at Nihoa Island or Gardner Pinnacles.

Factors Affecting Survival

Unknown factors led to at least 1 life-threatening condition at Necker Island that 

resulted in the confirmed death of 1 animal: a dead adult seal, sex unknown, observed on

July 30. In addition, an adult female was observed with a dorsal mounting injury of

unknown severity in September 2001. No factors affecting survival were observed on

Nihoa Island, Gardner Pinnacles, or Maro Reef in 2001. 

ACKNOWLEDGMENTS

We acknowledge the support of the U.S. Fish and Wildlife Service; Hawaiian

Islands National Wildlife Refuge staff; and the captain, officers, and crew of the NOAA

ship Townsend Cromwell for logistical assistance. We also thank USFWS personnel for

collecting seal counts at these sites in August and September.

103

REFERENCES

105

Alcorn, D. J.

1984. The Hawaiian monk seal on Laysan Island: 1982. U.S. Dep. Commer.,

NOAA Tech. Memo., NOAA-TM-NMFS-SWFC-42, 37 p.

American Society of Mammalogists, Committee on Marine Mammals.

1967. Standard Measurements of Seals. J. Mammal. 48:459-462.

Boness, D. J.

1990. Fostering behavior in Hawaiian monk seals: is there a reproductive cost? 

Behav. Ecol. Sociobiol. 27:113-122.

Boness, D. J., M. P. Craig, L. Honigman, and S. Austin.

1998. Fostering behavior and the effect of female density in Hawaiian monk

seals, Monachus schauinslandi. J. Mammal. 79(3):1060-1069.

Gilmartin, W. G. and G. A. Antonelis.

1998. Recommended recovery actions for the Hawaiian monk seal population at

Midway Island. U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TMNMFS-SWFC-253, 14 p.

Gilmartin, W. G. and T. Gerrodette.

1986. Hawaiian monk seal status and recovery potential at Kure Atoll. Honolulu

Lab., Southwest Fish. Cent., Natl. Mar. Fish. Serv., NOAA, Honolulu, HI

96822-2396, Southwest Fish. Cent. Admin. Rep. H-86-16, 26 p.

Hiruki, L. M., Gilmartin, W. G., Becker, B. L., and Stirling, I.

1993. Wounding in Hawaiian monk seals (Monachus schauinslandi). Can. J.

Zool. 71:458-468.

Johanos, T. C. and Kam, A. K. H.

1986. The Hawaiian monk seal on Lisianski Island: 1983. U.S. Dep. Commer.,

NOAA Tech. Memo., NOAA-TM-NMFS-SWFC-58, 37 p.

Johanos, T. C., A. K. H. Kam, and R. G. Forsyth.

1987. The Hawaiian monk seal on Laysan Island: 1984. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-70, 38 p.

Kenyon, K. W.

1972. Man versus the monk seal. J. of Mammal. 53(4):687-696.

Lombard, K. B., B. L. Becker, M. P. Craig, G. C. Spencer, and K. Hague-Bechard.

1994. The Hawaiian monk seal on Laysan Island, 1990. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-206, 16 p.

Stone, H. S.

1984. Hawaiian monk seal population research, Lisianski Island, 1982. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-47, 33 p.

Winchell, J. 

1990. Field manual for phocid necropsies (specifically Monachus schauinslandi). 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-146,

55 p.

Yochem, P. K., R. C. Braun, B. R. Ryon, J. D. Baker, and G. A. Antonelis. 

2003. Contingency plan for Hawaiian monk seal unusual mortality events. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-PIFSC-1, 147 p.

107

APPENDIXES

A-1

Appendix A.--Reports summarizing annual field research on the Hawaiian monk seal by

the National Marine Fisheries Service and collaborating scientists.

All islands

Johanos, T. C., and J. D. Baker (Eds.).

2002. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 2000. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-340,

125 p.

Johanos, T. C., and J. D. Baker (Eds.).

2001. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1999. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-310,

130 p.

Johanos, T. C., and J. D. Baker (Eds.).

2000. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1998. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-292,

125 p.

Johanos, T. C., and T. J. Ragen (Eds.).

1999. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1997. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-262,

131 p.

Johanos, T. C., and T. J. Ragen (Eds.).

1999. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1996. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-259,

134 p.

Johanos, T. C., and T. J. Ragen (Eds.).

1997. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1995. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-241,

121 p.

Johanos, T. C., and T. J. Ragen (Eds.).

1996. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1993. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-227,

141 p.

Johanos, T. C., and T. J. Ragen (Eds.).

1996. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1994. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-229,

111 p.
Appendix A.--Continued.

A-2

Johanos, T. C., L. M. Hiruki, and T. J. Ragen (Eds.).

1995. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 1992. 

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-216,

128 p.

French Frigate Shoals

Craig, M. P., J. L. Megyesi, C. S. Hall, J. L. Glueck, L. P. Laniawe, E. A. Delaney, S. S.

Keefer,

 M. A. McDermond, M. S. Schulz, G. L. Nakai, B. L. Becker, L. M. Hiruki, and R. J. 

Morrow.

1994. The Hawaiian monk seal at French Frigate Shoals, 1990-91. U.S. Dep.

Commer., NOAA Tech. Memo., NOAA-TM-NMFS-SWFSC-210, 70 p.

Craig, M. P., D. J. Alcorn, R. G. Forsyth, T. Gerrodette, M. A. Brown, B. K. Choy, L.

Dean, L. M.

 Dennlinger, L. E. Gill, S. S. Keefer, M. M. Lee, J. S. Lennox, C. R. Lorence, G. L.

Nakai, and 

 K. R. Niethammer.

1992. The Hawaiian monk seal at French Frigate Shoals, 1988-89. U.S. Dep.

Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-178, 83 p.

Eliason, J. J., J. R. Henderson, and M. A. Webber.

1993. Hawaiian monk seal observations at French Frigate Shoals, 1985. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-187, 46 p.

Eliason, J. J., and J. R. Henderson.

1992. Hawaiian monk seal observations at French Frigate Shoals, 1984. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-177, 61 p.

Fairaizl, G. W.

1984. Intra-atoll resighting of the Hawaiian monk seal, Monachus schauinslandi,

at French Frigate Shoals, 1 January 1983-31 August 1983. Southwest Fish.

Cent. Honolulu Lab., Natl. Mar. Fish Serv., NOAA, Honolulu, HI

96822-2396. Southwest Fish. Cent. Admin. Rep. H-84-5C, 27 p.

Johnson, P. A., and B. W. Johnson.

1984. Hawaiian monk seal observations on French Frigate Shoals, 1980. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-50, 47 p.
Appendix A.--Continued.

A-3

Laysan Island

Alcorn, D.

1984. The Hawaiian monk seal on Laysan Island: 1982. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-42, 37 p.

Alcorn, D. J., and E. K. Buelna.

1989. The Hawaiian monk seal on Laysan Island, 1983. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-124, 46 p.

Alcorn, D. J., and R. L. Westlake.

1993. The Hawaiian monk seal on Laysan Island, 1986. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-191, 25 p.

Becker, B. L., P. A. Ching, L. M. Hiruki, and S. A. Zur.

1994. The Hawaiian monk seal on Laysan Island, 1987 and 1989. U.S. Dep.

Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-213, 20 p.

Becker, B. L., R. J. Morrow, and J. K. Leialoha.

1989. Censuses and interatoll movements of the Hawaiian monk seal on Laysan

Island, 1985. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TMNMFS-SWFC-135, 25 p.

Becker, B. L., K. E. O'Brien, K. B. Lombard, and L. P. Laniawe.

1995. The Hawaiian monk seal on Laysan Island, 1991. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-214, 16 p.

Johanos, T. C., and S. L. Austin.

1988. Hawaiian monk seal population structure, reproduction, and survival on

Laysan Island, 1985. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TMNMFS-SWFC-118, 38 p.

Johanos, T. C., B. L. Becker, M. A. Brown, B. K. Choy, L. M. Hiruki, R. E. Brainard, 

 and R. L. Westlake

1990. The Hawaiian monk seal on Laysan Island, 1988. U.S.Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-151, 24 p.

Johanos, T. C., A. K. H. Kam, and R. G. Forsyth.

1987. The Hawaiian monk seal on Laysan Island: 1984. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-70, 38 p.
Appendix A.--Continued.

A-4

Johnson, B. W., and P. A. Johnson.

1984. Observations of the Hawaiian monk seal on Laysan Island from 1977

through 1980. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TMNMFS-SWFC-49, 65 p.

Lombard, K. B., B. L. Becker, M. P. Craig, G. C. Spencer, and K. Hague-Bechard.

1994. The Hawaiian monk seal on Laysan Island, 1990. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-206, 16 p.

Lisianski Island

Alcorn, D. J., R. G. Forsyth, and R. L. Westlake.

1988. Hawaiian monk seal research on Lisianski Island, 1984 and 1985. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-120, 22 p. 

Johanos, T. C., and J. R. Henderson.

1986. Hawaiian monk seal reproduction and injuries on Lisianski Island, l982. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-64, 7 p.

Johanos, T. C., and A. K. H. Kam.

1986. The Hawaiian monk seal on Lisianski Island: 1983. U.S. Dep. Commer.,

NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-58, 37 p.

Johanos, T. C., and R. P. Withrow.

1988. Hawaiian monk seal and green turtle research on Lisianski Island, 1987. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-121, 18

p.

Lee, M. M., L. K. Timme, R. Van Toorenburg, and B. L. Becker.

1993. The Hawaiian monk seal on Lisianski Island, 1988 and 1990. U.S. Dep.

Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-179, 33 p.

Stone, H. S.

1984. Hawaiian monk seal population research, Lisianski Island, 1982. U.S. Dep.

Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-47, 33 p. 

Westlake, R. L., and P. J. Siepmann.

1988. Hawaiian monk seal and green turtle research on Lisianski Island, 1986. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-119, 18

p.
Appendix A.--Continued.

A-5

Pearl and Hermes Reef

Choy, B. K., and L. M. Hiruki.

1992. The Hawaiian monk seal and green turtle on Pearl and Hermes Reef, 1988. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-175,

18 p. 

Finn, M. A., J. R. Henderson, B. L. Becker, and T. J. Ragen.

1993. The Hawaiian monk seal and green turtle at Pearl and Hermes Reef, 1990

and 1991. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFSSWFSC-182, 29 p.

Forsyth, R. G., D. J. Alcorn, T. Gerrodette, and W. G. Gilmartin.

1988. The Hawaiian monk seal and green turtle on Pearl and Hermes Reef, 1986. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-107, 24

p.

Kure Atoll

Bowlby, C. E., P. Scoggins, R. Watson, and M. Reddy.

1991. The Hawaiian monk seal, Monachus schauinslandi, at Kure Atoll, 1982-

83. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC155, 28 p.

Gilmartin, W. G., R. J. Morrow, and A. M. Houtman.

1986. Hawaiian monk seal observations and captive maintenance project at Kure

Atoll, l981. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TMNMFS-SWFC-59, 9 p.

Henderson, J. R., and M. R. Finnegan

1990. Population monitoring of the Hawaiian monk seal, Monachus

schauinslandi, and captive maintenance project at Kure Atoll, 1988. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFSC-150, 24 p.

Reddy, M. L.

1989. Population monitoring of the Hawaiian monk seal, Monachus

schauinslandi, and captive maintenance project for female pups at Kure Atoll,

1987. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TMNMFS-SWFC-123, 37 p.
Appendix A.--Continued.

A-6

Reddy, M. L., and C. A. Griffith.

1988. Hawaiian monk seal population monitoring, pup captive maintenance

program, and incidental observations of the green turtle at Kure Atoll, 1985. 

U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-101, 35

p.

Van Toorenburg, R. A., W. G. Gilmartin, and J. R. Henderson.

1993. Composition of the Hawaiian monk seal population at Kure Atoll, 1990. 

Pac. Sci. 47(3):211-214.

Nihoa and Necker Islands

Conant, S.

1985. Observations of Hawaiian monk seals on Necker Island, Northwestern

Hawaiian Islands. 'Elepaio. 6(2):11-12.

Finn, M. A. and M. A. Rice.

1994. Hawaiian monk seal observations at Necker Island, 1993. 'Elepaio. 

55(9):55-58.

Morrow, R. J., and E. K. Buelna.

1985. The Hawaiian monk seal and green turtle on Necker Island, 1983. U.S.

Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWFC-55, 11 p.
B-1

Appendix B.--Hawaiian monk seal census form and 2001 census form directions.

(See following pages.)

DATA TYPE 

SEAL d FORM 

PAGE OF 

DATE NUMBER llMP. [77mmImhx 

NOTES 

ID TAG EVENT - w 

Codes 

8 

9 

u 

19 

l3 

l4 

\ 
ID TAB Erma 

1 4 ~i!; s3?3FT ea Coder 

b 

16 

11 

- 

tb I 

19 

PQ 

rn 

PP 

-. 

93 

84 

m 

w 

150 
2001 

CENSUS FORM DIRECTIONS 

(Unabr~dged - Laysan and L~s~an\k~ Island\) 

This form is used to record all Hawaiian monk seal and green turtle sightings. Turtlc sightings are recorded 

only during ccnsus aclivities (not during patrols), unless noteworthy event occurs (turtle injured, tagged. 

tumorcd, mating. c~c.). On tlic ccnsus Sorni. all dala tlial can bc recorded for seals can also bc rccordcd for 

~LISLICS (although 11iis data may not be required). At French Frigate Shoals, do not record a data line for 

each turtle sighting; instead, write the total for each sizelsex class at the bottom of the page. 

All original data should be coded in pcncil. Never erasc dala oncc you I~avc lcfl the rccording sitc. Inslcad, 

cross errors out with a single line. Field editing is editing before running the data cntry and checking 

prograni. All field editing by tlie data collector sliould be in blue, and field editing by others shoultl bc in 

scd. As soon as you begin the entry and checking program, tlie computer will assign the computer page 

numbcr and display it on the screen. At tliis point. be sure to fill it in on yo~a census form. All editing aftcr 

tliis point shoultl be in orange. After completing the entry and checking program, chcck off and initial thc 

ENTERED box on the census forla. 

A separate data slrect sliould bc I'illcd o~~t lor each date, observer, data type. ant1 island within an atoll. If no 

seals are present, you should still fill out tl~c information a1 thc lop ol'11ic ccnsus form and writc "No seals" 

in the data arca (only cntcr thc hcadcr inf'orn~ation). If tlie island itself is not present, indicate this by using 

- 99 for the sector code, leaving [lie rcst of the (lirst) linc blank. To savc papcr, you sliould LISC a ccnsus form 

with multiple headers if you only havc a fcw scals to rccord (i.c.. a1 so~uc islands within an atoll, or when 

recording incidcn~al siglitings bclbrc or aflcr ccnsus or patrol). In cssencc, on a census form with ~nultiple 

headers, each header and ils associatcd lincs rcprcscnts a separate data shcet. 

If two people contluct the census, they should havc thc saluc wcalhcr and tlic samc bcgin and cnd time (i.e., 

both begin at the same time and place. and procccd in oppositc directions unlil tlicy meel on Lhc othcr side 

of tlie islantl or islet) and combinc pagcs into onc sct. Patrols may bc conducted by more than onc observer, 

but pagc sets arc not combined, and header information may differ between page sets. Patrol observers 

should attempt to start at roughly tlic samc timc. Tlic sum of all obscrvcrs' patrol activity for a day should 

result in one complete island count. 

Always record disturbance. You must bc I~oncst aboul lhis! Fill oul a ccnsus form to docu~ncnl 

disturbance if you dist~~rb a seal when you are not otherwise collecting dam. On a ccnsus or aloll counl, it is 

also assumed that condition and molt data will bc taken. 

Do not make up additional codes. If the need for an additional codc arises, conlact Honolulu. 
PAGE HEADER 

DATA TYPE 

C =Census: A complete. timed count on an island begun around 1300. Census is conductccl 

as quickly as possible (while gathering all inSormation). Data collected on all seals ant1 turtlcs 

A= 

Atoll-wide census (must be completed within 2 consecutive clays). Data collected on all scals and 

turtles. 

B = 

Behavior patrol: A co~nplcte, untirned count where size, sex. ID and disturbance are recorded. 

Associations are assumed to be coclecl for all scals (In 2001, collect only at Laysan and Lisianski 

Isla~lds. codc behaviors for all AdultIS4 seals and their associated seals, otherwise code behavior 

X (clata not takcn). Record t~lrtlcs only if notewol.tt~y ohscl-vation. 

P = 

Patrol: A complete, untimcd count where size, sex. ID and disturbance arc recorded. Behavior 

data is not takcn. Record turtles only if note\vortIiy observation. 

I = 

Inciclcntal observation. In this data type. null fields arc interpretecl ns "data not recorded", so codc 

Jntn explicitly. If numberedl this indicates a lull island incidental with year-specific goals. At 

Laysan and Lisianski Islands in 2001, these surveys will record mother-pup pairs, weanecl pups. 

nloltcrs, survival Sactors, major behavioral events (i.c.. scvcrc h~trassments and mobbingsl and 

other noteworthy observations. 

T = 

Tag status entry I'or non-active tags (tags not currently olt a seal). Record tag status (F or R) in 

notes columns. 

COMPUTER PAGE NO. 

Leave this blank during data collection. It will be assigned and displayed 011 the screen when you 

cntcr the data. At that time, be sure to rill in the computer paFc number on your ccnsus form, as 

this number is needed I'or data retrieval. 

PAGE Page number within 21 CCI~SUS or patrol. For example, if the census (or patrol) recluires thrcc 

pages. then mark the first paee as "pagc I 01'3" and so on. If morc than 1 persolt conducts the 

census, the11 combine pagc numbers; person A 11as pages I ancl 2, whilc person B has pagcs 3 

and 4 of a four-page census day. The maxllnum nu~nhel. of pagcs in a set is 9. Hcadcr 

inl'orlnation (time beginlend. clatc. n~~niber, and wcn~licr) should be the samc I'or all pages 

within a sc~. 

ISLAND Name ol'islancl and atoll, c.g., Ea.;t. FFS. 

OBSERVER 

TI]]-cc initials. If no middle initial, use the first and last block. 

TIME BEGIN and END 

On a 24-11 clock. c.g.. 6 p.m. = 1800. for the group of pages. Midway uses hlidwny time, all other 

sites use Hawaii Sla~tdard time. 

DATE The date that data arc collected (~n YYYYMMDD format). 

NUMBER Censuses. Atoll counts, Behavior patrols, and Patrols must he numbered. Each data type will 

have its own 3 digit nunthcr series, starting with 00 1. For data types other than A, have a 

separate number series l'or each islet within an atoll. 

Weather irlforrrmtion (except terr~perat~cre) should be a sllrrlrlrary of the entire day rrp urltil tlle end of tl~e 

cerlsus or patrol, trot ~nerely arl irlstarltarleo~~s observatiorr. Terrlperatures taker1 ir~ tlle r~zorrzir~g are not 

represerltative for the period of data collectiorr. 
TEMP. Temperature In degrees Cclaiua at beginning of census or patrol. 

WIND Spccd:O = no wind. calm (4 knots) 

I = light breeze (5- 15 knots) 

2 = strong wind (> 15 knots) 

Direction:NN2NE,EE,SE.SS,SW.WW,NW 

Thus, 2 N N = strong wind from nortl~ 

CLOUD Cloud cover: 00 = no clouds 

0 1-09 = 10 to 90% cove] 

10 = 100% cover 

PREC. PI-ccipilution: 0 = no precipitation or trace 

I = mist/drizzle 

2 = rain 

3 = inter~nittent ruin 

LINES 

CONTINUE lf rhc sarne seal sicl1tin.q is recorded on several lines for any reason (e.g., additional tag or 

association, belia\,ior at a later tirne, change of bcach position), put the orioinal line 

number you arc continuing fi.om here. Lines may be continued only willlin thc same page. 

Fill in the original linc as completely as possible. During entry, the data in all I'iclds from 

TIME through MOLT niust be copied from rhc original line if left blank on the 

continuation line. Several lines can have the same continualion line number. 

Make a new original line (i.e. do not LISC continuat~on I~nes) Sol- a seal each time tl~at you 

come abreast of it on ccllsus or patrol. 

TIME The time should be recorded I'or each seal sighring. on a 24-h clock 

SECTOR Location on island (c.g., 1-20 on Laysan) 

Special codes as follows: 

00 = unknown sector 

77 = pen 

SS = offshore spit/cmergent reel' 

99 = island not present 

SIZE Size is estimated using a classification scheme from Stonc ( 1984), using thc following 

rcrminology. Note that seals arc "sized" by length. girth, appearance, and reproductive status, nor 

hy age (except pups): 

PUP Scals bol-11 within the calendar year. Newhorn pups are black. and weight ca. I I 

to 15 kg. Pups molt to a silver-gray pelage near weaning. Weaning \vcight is ca. 

50 to 80 kg. 

Juvenile Short, slight seals from the length of a weaned pup (about 138 cm) to 20-30 cm 

longcr; includes yearlings, and other young seals up to 3 years. Distinguished 

from pups by th~nness and yellowish color. 

Suhadulrs Seals perceptibly longer than juveniles up to breedin2 size; less robust than 

adults, generally with lighlcr pclage. Imlnature seals cn. 3 to 5 or 6 years old. 

Adult Reproductively actiw or hrecding si~c seals at least us long as known bl.ccders. 

Mature or probably mature scals. Adult females often have cxtcnsi\,c hack scars 

or wounds; adult males usually dark, including ventrum, and cxtensivcly scarred. 
Code sizc as t'ollows: 

Pups ot' the pear 

PO = Fetus (aborted, clearly prc-terrn pup) 

P = Nursing pup 

PI = Nursing pup; wrinklcs 

P7 = Nursing pup, no wrinklcs 

P3 = Nursing pup, blimp. hlack 

P4 = Nursing pup, molting 

P5 = Nursing pup, molted 

PW = Prematurely wcancd/unde~.si~ed wca~icd pup (wcaned 2 wks ago and < 90cm 

girth). Codc as PW at time of weaning, and thcn can code as W for rcmninder of 

season. 

W = Weaned pup 

Inimalurcs 

I = Immature 

.I = Juvcnilc 

.I I = Juvenile I 

J2 =Juveriile I1 

S = Subndult 

S.3 = Subadult 111 

S4 = Subadult IV 

Adults 

A =Adult 

Unknowns 

U = Seal of unknown sizc 

Turtles 

T = Turtle (lengths from antcrior to posterior tip ol'carapace) 

TI = Turtle, juvenile (45 cm straiglrt carapace Icngth) 

T2 =Turtle, subadult (6.5 - 80 cm) 

T3 = Turtlc, adult (>SO cm) 

O~rly code a seal's SEX ay know~l iftlie ventral is seen, even if yo^^ "know" the sex beca~~se oj'tlre tag, 

61euclr, scary, or belravior. Tlre only exceptio~r is tlrat tlze motlrer in a niotlier/pllp pair .sho~~lrf be 

recorrferf ur a fe~nule. The sex (fa turtle can o~zly be rfisti~lg~iisherf exterrinlly if it is adult-sizerf. 

SEX M= nipples Female <<- Adult I;c~n:ile\ :i[ld 

Male I~~~~~~~II~I~c, 01 hlth h~x~5 ~l~ll 111.11~\ 

F = 

Fcrnale 

U= lumbilicus 

Unknow 

n 

penile opening and groove 
BEACH POS. Location of seal or turtle wlien ohserver comes ahreast of animal (e.g.. if seal is sccn in 

tllc water from a distance and yet is on the hcach when the observer come ahrca5t. the seal 

is recorded 2:s hcing on tlle beach). When recorcling interactions (at Laysan and Lisinnski 

Islands in 2000), record hchaviors as you scc them ahead of yo^^ (within 30 m). When 

you come ahrcast of the seal. record the beach position and time r~nci makc this your 

original line. All previously recorded lines for this sigllting will he revcrsc continuation 

lines. 

0 = animal iloating or swimming in \vatel- (not included in census tally but may he 

used for hcliavioral data or o111cr aualysis). 

1 = on tlle beach (or regularly sur\rcycd arcas on the fringing reef for Midway Reef 

Surveys) 

9 = on an olSshore rock11-ccl'witll no connections to the island. Separated from shore 

by a dccp channel or substantial distance, and not regularly surveyed (not 

includect in census tally). For Midway Reef Surveys, use heact1 position 9 for 

the hack side of tllc reef and other arcas that are not rcgularly surveyed. 

X = data not taken 

CONDITION Condition is rccorded fol- all seals (except nursing pups) on census or atoll count. Always 

record tlrc condition of thc Inom on her first sighting postpartum, and of the mom and 

pup on their first sighting post-weaning, regardless of data type. Always note condition 

wlien recording a survival I'actor. 

Condition cocles: 

M = medium 

P = probably pregnant 

F = l'at 

T = thin. includes emacia~cd 

X = data not takcn 

Codes F and T indicate extreme condit~ons, seals that are medium-fat, or medium-thin 

should he coded as medium. Always code condition explicitly. 











Availability of NOAA Technical Memorandum NMFS

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In addition, this series and a wide range of other NOAA documents are available in

various formats from the National Technical Information Service, 5285 Port Royal Road,

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charged.