NOAA Technical Memorandum NMFS-PIFSC-28

October 2011

The Hawaiian Monk Seal in the

Northwestern Hawaiian Islands, 2004

Compiled and Edited by

Thea C. Johanos and Jason D. Baker

Pacific Islands Fisheries Science Center

National Marine Fisheries Service

National Oceanic and Atmospheric Administration

U.S. Department of Commerce
About this document

The mission of the National Oceanic and Atmospheric Administration (NOAA) is to 

understand and predict changes in the Earth=s environment and to conserve and manage 

coastal and oceanic marine resources and habitats to help meet our Nation=s economic, 

social, and environmental needs. As a branch of NOAA, the National Marine Fisheries 

Service (NMFS) conducts or sponsors research and monitoring programs to improve the 

scientific basis for conservation and management decisions. NMFS strives to make 

information about the purpose, methods, and results of its scientific studies widely available.

NMFS= Pacific Islands Fisheries Science Center (PIFSC) uses the NOAA Technical 

Memorandum NMFS series to achieve timely dissemination of scientific and technical 

information that is of high quality but inappropriate for publication in the formal peerreviewed literature. The contents are of broad scope, including technical workshop 

proceedings, large data compilations, status reports and reviews, lengthy scientific or 

statistical monographs, and more. NOAA Technical Memoranda published by the PIFSC, 

although informal, are subjected to extensive review and editing and reflect sound 

professional work. Accordingly, they may be referenced in the formal scientific and 

technical literature.

A NOAA Technical Memorandum NMFS issued by the PIFSC may be cited using the 

following format:

Johanos, T. C., and J. D. Baker (compiled and edited). 

2011. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 2004.

U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-28, 

112 p. + Appendices.

__________________________

For further information direct inquiries to

Chief, Scientific Information Services

Pacific Islands Fisheries Science Center

National Marine Fisheries Service

National Oceanic and Atmospheric Administration

U.S. Department of Commerce

2570 Dole Street

Honolulu, Hawaii 96822-2396

Phone: 808-983-5386

Fax: 808-983-2902

___________________________________________________________

Cover: Photograph courtesy of Brenda Becker, NOAA Fisheries.
Pacific Islands Fisheries Science Center

National Marine Fisheries Service

National Oceanic and Atmospheric Administration

U.S. Department of Commerce

The Hawaiian Monk Seal in the

Northwestern Hawaiian Islands, 2004

Compiled and Edited by

Thea C. Johanos and Jason D. Baker

Protected Species Division

Pacific Islands Fisheries Science Center

National Marine Fisheries Service

1601 Kapiolani Boulevard, Suite 1110

Honolulu, Hawaii 96814-4700

NOAA Technical Memorandum NMFS-PIFSC-28

October 2011

iii

EXECUTIVE SUMMARY

During 2004, 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. In 2004, 198 pups were counted at these sites, 61 of which were born at French Frigate 

Shoals (FFS). Although a record number of pups were born at Pearl and Hermes Reef and 

Midway Atoll, and pup numbers increased at all sites over the previous year, pup numbers at 

FFS remained well below historic levels. Mean beach counts, excluding pups, from the main 

reproductive sites totaled 361.4 seals. Although beach counts remained essentially unchanged 

from 1993 to 2000 and declined in 2001-2004, counts in 2004 were higher than those of the 

previous 3 years (Fig. 1b). 

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

of the animals counted while juveniles and subadults declined (Fig. 1c) and, in 2004, 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.

In 2004, the following 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: (1) disentangling 11 seals and 

removing debris capable of entangling seals from all study sites; (2) moving 4 weaned pups 

stranded on the runway at FFS to the water’s edge; (3) translocating 29 weaned pups between 

islets within FFS to decrease their risk of shark predation; (4) cutting the umbilical cords to 

remove placentas from 2 newborn pups at risk of drowning or attracting sharks at FFS; (5) 

performing 8 human-assisted pup exchanges and uniting an abandoned pup with a female that 

had lost a pup to increase pup survival at FFS; (6) interrupting two incidents of aggressive males 

mounting weaned pups at FFS and Kure Atoll; and (7) monitoring beaches at Midway Atoll for 

disturbance and mitigating human impacts through education.
iv

This document describes these and other field studies conducted during 2004 and 

provides complete standardized 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

Figure 1.--Demographic trends of the Hawaiian monk seal, based on the main reproductive sites. 

(A) Number of pups born (minimum). (B) Total of mean beach counts, excluding pups, with 1 

standard deviation. (C) Percentage of counts made up of adults, subadults, juveniles, and pups.
vi

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vii

CONTENTS

Page

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

MATERIALS AND METHODS........................................................................................ 2

Censuses and Patrols............................................................................................... 2

Reproduction........................................................................................................... 3

Factors Affecting Survival.......................................................................................3

Individual Identification...........................................................................................4 

Measurements of Seals ............................................................................................5

Collection of Samples...........................................................................................5

CHAPTER 2. THE HAWAIIAN MONK SEAL ON

FRENCH FRIGATE SHOALS, 2004 .............................................................................................7 

RESEARCH.........................................................................................................................9

Censuses and Patrols................................................................................................9

Individual Identification.........................................................................................10

Collection of Samples............................................................................................10

Special Studies.......................................................................................................11

Galapagos Shark Predation and Monitoring..............................................11

Translocation of Weaned Pups..................................................................11

Juvenile Nutritional Enhancement–Second Chance Project......................11

Tern Island Monitoring for Seawall Reconstruction Project .....................12

Noteworthy Events.................................................................................................12

Human Intervention ...................................................................................12

RESULTS ..........................................................................................................................12

Subpopulation Abundance and Composition.........................................................12

Reproduction..........................................................................................................13

Interatoll Movement...............................................................................................13

Factors Affecting Survival.....................................................................................13

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

TABLES ............................................................................................................................17

CHAPTER 3. THE HAWAIIAN MONK SEAL ON

LAYSAN ISLAND, 2004............................................................................................................. 29

RESEARCH...................................................................................................................... 31

Censuses and Patrols............................................................................................. 31

Individual Identification........................................................................................ 31

Collection of Samples........................................................................................... 32

RESULTS ......................................................................................................................... 32

Subpopulation Abundance and Composition........................................................ 32

Reproduction......................................................................................................... 32

Interatoll Movement.............................................................................................. 32

Factors Affecting Survival.................................................................................... 33

ACKNOWLEDGMENTS ................................................................................................ 33
viii

TABLES.......... .............................................................................................................. 35

CHAPTER 4. THE HAWAIIAN MONK SEAL ON 

LISIANSKI ISLAND, 2004 ......................................................................................................... 45

RESEARCH...................................................................................................................... 47

Censuses and Patrols............................................................................................. 47

Individual Identification........................................................................................ 47

Collection of Samples........................................................................................... 48

RESULTS ......................................................................................................................... 48

Subpopulation Abundance and Composition........................................................ 48

Reproduction......................................................................................................... 48

Interatoll Movement.............................................................................................. 48

Factors Affecting Survival.................................................................................... 48

ACKNOWLEDGMENTS ................................................................................................ 49

TABLES ........................................................................................................................... 51

CHAPTER 5. THE HAWAIIAN MONK SEAL ON

PEARL AND HERMES REEF, 2004 ...........................................................................................61

RESEARCH.......................................................................................................................63

Censuses and Patrols..............................................................................................63

Individual Identification.........................................................................................63

Collection of Samples............................................................................................63

RESULTS ..........................................................................................................................64

Subpopulation Abundance and Composition.........................................................64

Reproduction..........................................................................................................64

Interatoll Movement...............................................................................................64

Factors Affecting Survival.....................................................................................64

ACKNOWLEDGMENTS .................................................................................................64

TABLES ............................................................................................................................65

CHAPTER 6. THE HAWAIIAN MONK SEAL ON

MIDWAY ATOLL, 2004 ..............................................................................................................75

RESEARCH.......................................................................................................................77

Censuses and Patrols..............................................................................................77

Individual Identification.........................................................................................77

Collection of Samples............................................................................................77

Noteworthy Events.................................................................................................78

Beach Monitoring and Public Education ...................................................78

RESULTS....... .................................................................................................................78

Subpopulation Abundance and Composition.........................................................78

Reproduction..........................................................................................................78

Interatoll Movement...............................................................................................78

Factors Affecting Survival.....................................................................................79

ACKNOWLEDGMENTS .................................................................................................79
ix

TABLES ........................................................................................................................... 81

CHAPTER 7. THE HAWAIIAN MONK SEAL ON

KURE ATOLL, 2004.....................................................................................................................89

RESEARCH.......................................................................................................................91

Censuses and Patrols..............................................................................................91

Individual Identification.........................................................................................91

Collection of Samples............................................................................................91

Noteworthy Events.................................................................................................92

Aggression Towards Weaned Pups ...........................................................92

RESULTS ..........................................................................................................................92

Subpopulation Abundance and Composition.........................................................92

Reproduction..........................................................................................................92

Interatoll Movement...............................................................................................92

Factors Affecting Survival.....................................................................................93

ACKNOWLEDGMENTS .................................................................................................93

TABLES ............................................................................................................................95

CHAPTER 8. THE HAWAIIAN MONK SEAL ON

NIHOA ISLAND, 2004...............................................................................................................105

RESEARCH.....................................................................................................................107

Censuses and Patrols............................................................................................107

Individual Identification.......................................................................................107

Collection of Samples..........................................................................................107

RESULTS ........................................................................................................................107

Subpopulation Abundance and Composition.......................................................107

Reproduction........................................................................................................108

Interatoll Movement.............................................................................................108

Factors Affecting Survival...................................................................................108

ACKNOWLEDGMENTS ...............................................................................................108

REFERENCES ............................................................................................................................109

APPENDIXES

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 2004 census form directions. ...................B-1
x

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CHAPTER 1. GENERAL INTRODUCTION

The endangered Hawaiian monk seal’s (Monachus schauinslandi) current core range is 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 were established for periods of several days to 

9 months to monitor and enhance the recovery of this species. Limited population monitoring 

has also been conducted at Nihoa and Necker Islands, where subpopulations appear to be limited 

to a small number of animals by availability of haulout area. Reports summarizing previous 

NMFS research are listed in Appendix A.

In 2004, 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) disentangling 

seals; and (10) removing debris capable of entangling seals from beaches. Location-specific 

objectives and summaries of data collected during the 2004 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: Special Use Permits HWN-12521-0211, HWN-12521-

0219, and SEPO-100102, and Marine Mammal Permit 848-1335.
2

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. 

Although data were collected on all seals, those that were in the water, captive 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 population size but 

provided an index of population 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 and every 4 to 8 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 a 2-day period. 

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 on foot of an entire island perimeter. 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 which 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 aggregations (defined below); (3) entanglements in 

marine debris; (4) injuries; and (5) deaths.
3

Reproduction 

Parturient females were identified when possible, and birth and weaning information was 

recorded. Because parturient females will 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 two lactating 

females were switched or one nursing female suckled multiple pups. Typically, such exchanges 

occur during an aggressive interaction between the two females. On other occasions, a mother 

and pup become separated, and one or both seals 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 for seals at FFS because higher 

population 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 one 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.Prior to 2002, nursing or lactation periods 

of less than 20 days were also excluded from calculations.

Factors Affecting Survival 

The origins of a wide range of injuries were distinguished based on characteristic wound 

patterns described in Hiruki et al. (1993). Injuries were documented if they were related to 

attacks by large sharks, mounting attempts by male Hawaiian monk seals or entanglement in 

marine debris or if they were considered severe enough to possibly affect survival. Injuries were 

considered severe and were summarized if they consisted of (1) the total combined area of all 

abscesses or abscess-like raised areas was > 8 cm diameter circle area (approximately 50 cm2) ; 

(2) an amputation of a minimum of half a flipper (either foreflipper or hindflipper); (3) the total 

combined exposed area of all punctures or gaping wounds is > 8 cm diameter circle area; 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 impaired seal movement. Major healed injuries 

that had been 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 died during the 

calendar year. A seal was listed as probably dead if it sustained severe injuries or was emaciated 
4

(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 for the field season, or (2) the seal was in 

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 for the field 

season (whichever was longer). Nursing pups were listed as probably dead if they disappeared 

within 3 weeks of birth. Losses of apparently healthy older nursing pups (over 3 weeks of age) 

and newly weaned pups (within 2 weeks post-weaning) were listed as disappeared, suspected 

dead, if the pups were last seen at a minimum of 10 surveys or 1 month before the end of data 

collection.

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

observed and recorded. By definition, multiple male aggression occurred when more than one 

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 where an 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 one male aggressor or resulted in a minimum of one puncture 

or gaping wound (missing skin or extending into the blubber layer) or > 15 scratches to the 

dorsum or flanks or if intervention was required to prevent drowning. Post-aggression 

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 hind flipper 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; since 1982 at Lisianski Island; since 1983 at Laysan Island and Pearl and Hermes 

Reef; since 1984 at French Frigate Shoals; and since 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 posterior dorsum (all subsequent years) of most weaned pups. 

 

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

Fisheries Service, NOAA.
5

In 2004, untagged immature and adult seals were opportunistically tagged with Temple 

Tags uniquely coded to indicate unknown ages and birth locations. 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) by using the 

solution described in Johanos et al. (1987), and applied bleach marks were photographed and 

sketched onto scar cards. 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 post-natal molt to 

facilitate identification during the nursing period.

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

folders throughout the field season to maintain a current description of the identifying marks of 

each seal.

Minimum subpopulation abundance and size-sex composition are presented. These 

statistics included all individuals observed alive at the location during the interval from March 

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

The movement of seals among 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 seal 

identified to just one subpopulation are applied as follows. If a seal was observed at more than 

one location during March–August, it was included exclusively in the subpopulation where it 

was sighted nearest to May 15, unless it pupped or molted at another location. A parturient 

female was always exclusively included in the subpopulation where she pupped, and a 

nonparturient seal was exclusively included in the subpopulation where it molted. Pups were 

always exclusively included in the subpopulation where they were born.

Measurements of Seals 

Pups were measured to provide information on condition. Measurements were taken as 

soon after weaning as possible, and measurements taken within 2 weeks after weaning were 

included in the summaries. Measurements included straight dorsal length (Winchell, 1990) and 

axillary girth (American Society of Mammalogists, 1967). Some older animals captured for

retagging 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 
6

recently. Samples of placentas found with or from aborted fetuses or deceased perinatal pups 

were also collected. 

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. Detailed descriptions of necropsy procedures and sample collection methods are 

in Winchell (1990).

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

(Goodman-Lowe, 1998). These samples were collected from seals of known size and sex class, 

when possible. 

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

from beaches. From 1982 to 1998, potentially entangling marine debris was incinerated on site 

at all locations, and debris incineration continued at Kure Atoll through 2001. More recently, 

marine debris was removed by ship.
7

CHAPTER 2. THE HAWAIIAN MONK SEAL ON

FRENCH FRIGATE SHOALS, 2004

Suzanne M. Canja, Aaron Dietrich, Daniel F. Luers, Jean M. Higgins, 

Frans A. Juola, and Brenda Becker
8
9

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

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

Islands. This atoll is part of the Hawaiian Islands National Wildlife Refuge and the 

Papahānaumokuākea Marine National Monument (Fig. 1.1), and consists of nine permanent 

islets (Disappearing, East, Gin, Little Gin, La Perouse Pinnacles, Round, Shark, Tern, and Trig), 

three semi-permanent 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. In 2004, research was conducted by NMFS from April 21–September 16 and 

October 17–December 28. The U.S. Fish and Wildlife Service (USFWS) also performed surveys 

exclusively on Tern Island during January 6– July 12 associated with a shoreline reconstruction 

project and conducted opportunistic observations throughout the atoll during the rest of the year. 

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

sectors using artificial or natural landmarks. In 2004, as part of the seal and turtle monitoring 

during the shoreline reconstruction project on Tern Island, additional sectors were created to 

record locations along the seawall and rock revetment areas. Research activities specific to this 

subpopulation in 2004 included (1) monitoring and removal of Galapagos sharks preying on 

monk seal pups throughout the atoll; (2) translocating newly weaned pups to reduce their risk of 

shark attack; (3) retagging or newly tagging seals; (4) rehabilitating juvenile seals in poor 

condition, referred to as the “Second Chance” Project; and (5) monitoring Hawaiian monk seals 

and green sea turtles during the Tern Island shoreline reconstruction project.

Censuses and Patrols 

Atoll-wide censuses (n = 14) were conducted every 8 d, on average, from May 17 to 

August 30. Each atoll census required 1 to 2 days to complete. Disappearing, Round, 

Whaleskate, Bare, and Mullet Islets were surveyed either on foot or by boat; while the remaining 

islets (East, Gin, Little Gin, Shark, Tern, and Trig) were censused on foot by 1- 4 people. La 

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

Bare Islet intermittently stayed above water during the season and Mullet completely 

submerged by July 20, 3 weeks sooner than in the 2003 season. Whaleskate Islet also went 

awash by August 26, after having been present throughout 2003, including the fall/winter months 

of 2003-04. Disappearing Islet remained present throughout the entire season and during the fall 

months, whereas in recent years it submerged by the end of the summer season. Both Trig and 

Round Islets had small spits adjacent to them by late April which lasted 2-3 months. 

Individual islet censuses, patrols, and incidental surveys were scheduled to ensure 

monitoring of the entire atoll at least once each week during May 17–August 31. However, 

surveys at all islands except Disappearing commenced April 21. Surveys were more frequent at 
10

islets where most pups were born and nearby sites, and sites of high shark activity: Trig and 

Round were monitored every 1–2 d on average; East every 1–3 d; Gin, Little Gin, and Mullet 

Islets every 2–4 d; Tern every 2–5 d; Shark and Whaleskate every 3–5 d; Disappearing every 6–7 

d; and Bare averaged every 4–10 d. 

From September 1 to 13, a combination of patrols and incidental surveys were conducted 

solely at Trig, Round, East, Gin, Little Gin and Tern Islets every 2–8 days to monitor nursing 

pairs and to document factors that may affect survival. During October 17–December 28, patrols 

and incidentals were conducted throughout the atoll primarily to monitor the condition of 

juvenile seals for potential inclusion in the Second Chance Project described in the following 

pages. Other activities included seal resights; monitoring mother/pup pairs, molting seals, and 

factors affecting survival; and seals were bleach marked post-molt. 

Individual Identification 

A total of 298 individuals (237 excluding pups) were identified by existing or applied 

tags and bleach marks, scars, or natural markings. Bleach marks were applied to 127 seals, 

including 18 nursing pups. Forty-seven weaned pups were tagged with Temple Tags; 46 of 

which also received a passive integrated transponder (PIT) tag. Two weaned pups were not 

tagged; one disappeared shortly after weaning and the other died from a severe shark bite. Five 

pups were tagged post-summer field season (4 in October, 1 in November). Additionally, 5 other 

seals (including 3 after the summer field season) were either newly tagged or retagged with 

Temple Tags and 3 of these also received a PIT tag. These included 3 adults (2 male, 1 female), 

1 subadult (female) and 1 weaned pup (male) who had lost a tag. 

Collection of Samples

Skin punches were collected from 58 seals; 51 during tagging (1 seal tagged on two 

occasions) and seven during necropsies. Full necropsies were performed and tissue samples 

collected from five dead seals found at the study site, and only skin and nail samples were 

collected from two other decomposed seal carcasses. Skeletal samples were collected from two 

carcasses; a mummified juvenile on East Islet and a highly decomposed fetus on Disappearing. 

Sixty-one scats, four spews, one shed molt, and four fresh placenta samples were also collected. 

One hundred dried ticks were collected for epidemiological studies. And finally, one 

entanglement sample was collected from an adult female green sea turtle and all other potentially 

entangling marine debris was cleared from beaches and stored in a secure location on Tern Island 

pending removal.
11

Special Studies

Galapagos Shark Predation and Monitoring

 In contrast to the previous 3 years of this project, effort in 2004 focused on response to 

shark predatory events expanded to the full atoll using the same protocol and methodology used 

at Trig Island in previous seasons. Standardized observations (time/scan 15-min blocks) were 

conducted on 41 days (697 15-min time blocks) between May 16 and August 13 among Trig, 

Round, and Gin Islets. These observations were generally conducted during times of known or 

suspected shark activity (including full and new moon phases). In addition, researchers stayed 

overnight for 4 nights on Trig Island to increase observations during early morning and late 

afternoon hours. 

In total, fishing/removal operations were conducted for 7 hours and 28 minutes over 3 

days at Trig Island when a Galapagos shark exhibited predatory behavior towards a preweaned 

monk seal. Only one shark attempted to take the bait, and no sharks were culled. Detailed 

results are presented elsewhere.

Translocation of Weaned Pups

To improve weaned pup survival, newly weaned pups were translocated to other islets 

within the atoll with lower evidence of shark activity. The majority of pups were moved on the 

day of or within 2 days of weaning, with four exceptions. One pup each from Gin and Little Gin 

were translocated 6–9 days postweaning after discovering a newly weaned pup had just 

disappeared from Gin. And two pups (1 Trig and 1 Gin) nursing at the end of the main field 

effort in September were translocated in October within 41 days postweaning. Of note, one Trig 

nursing pair disappeared for 1 day near weaning. The pup reappeared alone a day later and was 

then translocated.

Twenty-nine newly weaned pups from Trig (19), Gin (5), Round (4) and Little Gin (1) 

Islets were translocated. Eighteen were taken to Tern (15 from Trig and 3 from Round), 7 to 

East (5 from Gin, and 1 each from Little Gin and Trig), 3 to Whaleskate (all from Trig), and 1 to 

Shark (from Round). Additionally, 2 of 3 pups that were initially translocated from Trig to 

Whaleskate Islet 9 and 13 days earlier were then translocated a second time to East Islet after 

Whaleskate became mostly awash by the end of July. The remaining pup had been on 

Whaleskate for 38 days postweaning and appeared to have adapted to the recent ephemeral state 

of the island. One abandoned female nursing pup on East Islet was translocated and fostered to a 

parturient female on Trig Islet shortly after the disappearance of her pup. And finally, one Trig 

Islet pup swam to Tern Islet near the time of weaning.

Juvenile Nutritional Enhancement - Second Chance Project

In efforts to improve survival of juveniles at FFS, seals in poor condition were to be 

captured and maintained in a shoreside pen on Tern Island where they would receive nutritional 

supplementation and then be released. A team of veterinarians, seal rehabilitation specialists, and 
12

monk seal field staff was deployed from October 17 to the Spring of 2005. Body condition of all 

juveniles was photo documented over the the fall and winter to monitor any changes during this 

period. However, no juveniles were considered to be in such a compromised state that they 

warranted supplemental feeding. 

Tern Island Seal Monitoring for Seawall Reconstruction Project

To monitor the potential impacts on haulout patterns of monk seals prior to and during 

the Tern Island seawall reconstruction project which began in 2003, USFWS personnel 

continued conducting weekly “rapid assessment” seal censuses from January 6 to July 12. These 

data were provided to NMFS for analysis of the impacts of this construction project.

Noteworthy Events

Human Intervention

 Researchers cut the umbilical cords (and collected placentas) of two newborn pups (one 

each on Trig and Gin) because the attached placentas restricted movement and placed the pups in 

danger of drowning or attracting sharks. Four weaned pups on the runway at Tern Island were 

transported back to the beach by researchers. In addition, researchers intervened and halted an 

incident of adult male aggression towards a weaned pup on Trig Islet.

Eight human-assisted pup exchanges (five on Trig, two on East, and one on Gin) 

occurred when researchers intervened to improve the survival of a nursing pup. Researchers also 

successfully fostered a small weaned pup from East to an adult female on Trig who had lost her 

pup within the previous 2 days. One attempt to reunite a newly weaned pup to its birth mother 

who had weaned another pup was unsuccessful. 

RESULTS

Population Abundance and Composition 

The mean of 14 atoll censuses was 113.9 seals (15.1 SD) including pups, and 86.6 seals 

(10.3 SD) excluding pups (Table 2.1). The total number of seals identified as part of the springsummer subpopulation was 284 individuals, 223 excluding pups (Table 2.2). This number 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 couldn't be uniquely identified. The numbers 

of tagged known-age seals born at FFS during the 1984 to 2003 period and resighted at any 

location in 2004 are summarized in Table 2.3.
13

Reproduction

 A minimum of 61 pups were born at FFS in 2004: 49 successfully weaned (including five 

nursing at the end of the NMFS summer field season and one born in late September), 9 died or 

probably died prior to weaning, 2 pups older than 21 days suspiciously disappeared prior to 

weaning, and the weaning status is unknown for one 9-11-day-old pup which was still nursing in 

September when the field team departed and was not seen when field personnel returned in 

October 40 days later (Table 2.4a). The following were birth locations for these pups: 25 born at 

Trig, 17 at East, 10 at Gin, 6 at Round, 2 at Little Gin, and 1 at Whaleskate. This is the first year 

since 1988 that no pups were born at Tern Island. One decomposed fetus was found on 

Disappearing Islet and was not included in the pup total. Nursing periods and measurements of 

weaned pups are summarized in Table 2.4b. The mean lactation period for 37 females was 38.1 

d (5.9 SD). One parturient female had an unusually long lactation period of 50–55 days and 

began molting during the final days before weaning. 

Thirty pup exchanges (22 Trig, 6 East, 2 Gin) were documented among 21 adult females 

and 21 pups; 7 of these events were observed and 8 others (5 on Trig, 2 on East, and 1 on Gin) 

involved human assistance to improve pup survival. These intervention events culminated in 11 

nursing pups (one pup twice) being reunited to a mother and 4 older pups were weaned by 

human assistance. This includes a pup abandoned at 27 days old on East Islet that was 

translocated and fostered to a parturient female on Trig whose pup had disappeared within the 

previous 48 hours. This female pup received an additional 15 days of nursing and successfully 

weaned. In addition (not included in the intervention total), researchers unsuccessfully attempted 

to reunite a smaller, unmolted newly weaned pup with its birth mom who had weaned a different 

pup 6 days previously and was still in good condition. One birth and one weaning were observed, 

both on Trig Islet. 

Interatoll Movement

Interatoll movement was documented for two seals that completed a total of two 

movements between FFS and either Laysan or Lisianski Islands (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 41 life-threatening conditions, which resulted in the confirmed 

deaths of 8 seals and the probable deaths of 6 seals (these 14 deaths/probable deaths include 9 

nursing and 1 weaned pups). In addition, 6 pups suspiciously disappeared and are likely dead (2 

nursing pups more than 3 weeks old, 3 pups 3–9 days postweaning, and 1 pup 10–51 days old 

that disappeared when field effort was temporarily discontinued) (Table 2.6). 
14

Of 61 pups born at FFS this year, 7 pups (3 weaned and 4 nursing) were seriously bitten 

by sharks: 4 died (2 at Trig, and one each at Gin and Round) and 1 disappeared (at Trig). Eleven 

additional pups (9 weaned, including one injured twice, and 2 nursing) received very minor shark 

injuries, not serious enough to include in Table 2.6. Two of these minor injuries occurred at East 

(one each to a weaned and nursing pup), one at Round (to a nursing pup) and two (both to 

weaned pups) at Gin. The islet where the other 7 minor injuries occurred could not be 

ascertained because they were inflicted on older weaned pups (more than 30 days postweaning) 

and these older pups move throughout the atoll. In one East Islet case, fresh shark injuries were 

documented on a female as well as her pup, with the mother incurring more severe injuries than 

the pup. She was at the end of her nursing period, in thin condition, and weaned her pup 1-3 

days after getting injured.

Shark attack also likely caused the disappearances of four other nursing pups; including 

the probable deaths of 2 young nursing pups and the suspicious disappearances of 2 older 

nursing pups. Two of these disappearances occurred at Gin, one at Little Gin, and one at Trig. 

Shark attack was suspected because the pups appeared healthy and normal when last seen. 

Additionally, in three of these four cases, the parturient female was present and actively 

searching for her missing pup, confirming that the pups had not been weaned. Another pup 

disappeared for unknown reasons; it was 9–11 days old and nursing on Trig at the end of the 

summer field camp in mid-September and was no longer present when researchers returned 40 

days later on October 19. In addition, 3 apparently healthy weaned pups disappeared within 3–9 

days of weaning. 

An adult female sustained moderate male mounting injuries, resulting in an abscess that 

almost completely healed during the season, and two incidents of adult male aggression towards 

weaned pups were witnessed (one on Tern and the other on Trig). Researchers intervened and 

halted the incident on Trig, and neither event resulted in obvious injuries. No seals were seen 

entangled this season, however researchers freed 1 adult green sea turtle from an aggregate of 

line wrapped tightly around its neck and right foreflipper. The turtle incurred very minor injuries 

where the line had cut into its skin.

In addition to the incidents presented in Table 2.6, a fetus was found on Disappearing 

Islet and seven seals were observed with healed moderate to severe shark injuries inflicted since 

the previous field season (1 adult male, 4 adult females, and a juvenile male and female). One 

nursing pup was observed with an eye opacity; there was no obvious trauma to the eye region 

and it is unknown if the pup’s vision was impaired. 
15

ACKNOWLEDGMENTS

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

staff and volunteers. Special thanks to Dominique Horvarth and Joe Wiggins for logistical 

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

grateful to USFWS Chris and Carrie Eggleston, Jennifer Tietjen, Steve Barclay, Heidi Hoffman, 

Todd Marse, Joe Spring, other staff and volunteers for conducting weekly Tern Island seal 

counts to monitor seal haulouts during the seawall project and providing additional observations 

and assistance with field work. We also thank contract veterinarian Dr. Robert Braun, and The 

Marine Mammal Center staff and volunteers, Tracey Goldstein, Dr. Frances Gulland, Jamie 

King, Cullen Meade, and Elizabeth Wheeler, for assistance with the Second Chance Project. We 

thank the captains, officers, and crew of the NOAA Ships Oscar Sette and Hi'ialakai, Coast 

Guard Cutter Kukui, and M/V Casitas, and the pilots of Pearl Pacific Enterprises. 
16

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17

TABLES

for French Frigate Shoals
18
19

Table 2.1.--Summary statistics for atoll censuses (n = 14) of Hawaiian monk seals at French 

Frigate Shoals from May 17 to August 30, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 58.5 8.5

 Male 18.7 3.2

 Female 36.1 7.8

 Unknown 3.7 3.1

Subadults 12.4 4.1

 Male 6.0 2.1

 Female 5.1 2.6

 Unknown 1.3 1.6

Juveniles 15.4 2.6

 Male 5.3 1.1

 Female 8.9 2.3

 Unknown 1.2 1.1

Pups 27.2 8.5

 Male 13.3 3.7

 Female 11.5 5.4

 Unknown 2.4 1.7

Non-pup Total 86.6* 10.3

Grand Total 113.9* 15.1

* Includes some seals not placed in any size class.
20

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

Shoals during the spring and summer of 2004. 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 63 93 0 156 0.7:1

Subadults 14 15 0 29 0.9:1

Juveniles 16 22 0 38 0.7:1

Pups 29* 29 3* 61* 1.0:1

Non-pup Total 93 130 0 223 0.7:1

Grand Total 122 159 3 284 0.8:1

* Includes perinatal pups (two male and one of unknown sex) that weren’t seen alive. 
21

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

resighted at any location in 2004.

Cohort Year

Age

(years) Sex

Number 

originally 

tagged

Number 

resighted

in 2004

1984 20 Male

Female

49

43

4*

7*

1985 19 Male

Female

48

38

2 

7 

1986 18 Male

Female

52

48

6*

15*

1987 17 Male

Female

55

51

5

5

1988 16 Male

Female

52

62

4

3

1989 15 Male

Female

51

50

5

4

1990 14 Male

Female

38

41

1

6*

1991 13 Male

Female

24

44

1

4*

1992 12 Male

Female

36

55

2

9*

1993 11 Male

Female

40

39

3

2

1994 10 Male

Female

47

48

1

7*

1995 9 Male

Female

29

26

2

10*

1996 8 Male

Female

39

30

3

3

1997 7 Male

Female

32

19

1

0

1998 6 Male

Female

49

39

4

4
22

Cohort Year

Age

(years) Sex

Number 

originally 

tagged

Number 

resighted

in 2004

1999 5 Male

Female

30

30

7

4

2000 4 Male

Female

27

30

3

4

2001 3 Male

Female

21

19

2

4

2002 2 Male

Female

25

28

11

16

2003 1 Male

Female

12

25

8

7

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

translocation. These seals were either released at Kure or Midway Atoll (n = 13) or remain in 

permanent captivity (n = 11).
23

Table 2.4a.--Summary of Hawaiian monk seals born at French Frigate Shoals in 2004.

Event

Number of pups

Male Female Unknown Total

Born 29a 29 3b 61

Died/probably died

 prior to weaning

4c 2 3b 9

Suspicious Disappearance 

 prior to weaning

1 1 0 2

Suspicious disappearance 

 weaning status unknown

1d 0 0 1

Weaned 23e 26 0 49e

Tagged 21f 26f 0 47

a One male pup was born after the NMFS summer field camp on Round Islet.

b One newborn pup never seen (alive or dead) at Gin, known gone because 2 females subsequently nursed

1 pup for 3 weeks.

c Includes 2 newborn pups found dead unknown cause (1 Trig, 1 Whaleskate).

d One male pup was nursing on Trig at the end of the NMFS summer field camp and was not seen again. e Two weaned pups were not tagged. One disappeared shortly after weaning and the other died from a

 severe shark bite.

f Four females and 1 male tagged in October and November, respectively (includes 4 of the 5 pups that

were still nursing at the end of the season and 1 pup born after the NMFS summer field camp).
24

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

Frigate Shoals in 2004. 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 38.8 107.6 125.0

Standard 

Deviation

5.5 8.3 6.5

n 30 44 44
25

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

from other locations in 2004, summarized by movements between two locations. 

Original location Number of trips, size, and sex class

Lisianski Island 1 adult male

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

to other locations in 2004, summarized by movements between two locations. 

Destination Number of trips, size, and sex class

Laysan Island 1 adult female
26

Table 2.6.--Factors affecting Hawaiian monk seal survival at French Frigate Shoals in 2004. 

Outcome

Size Sex Total Injured Died Probably 

died

Suspicious 

Disappearance

e

Attack by Large Shark

Adult Male

Female

7a

6

7

6

0

0

0

0

0

0

Juvenile Female 1 1 0 0 0

Weaned pup Male 3 2 1 0 0

Nursing pup Male

Female

Unknown

1

2

1

0

0

0

1

2

0 

0

0

1

0

0

0

Mounting by Males

Adult Female 1 1 0 0 0

Weaned pup Male

Female

1b

1c

0

0

0

0

0

0

0

0

Entanglement

(none observed)

Emaciation

Juvenile Male

Female 

1

2

0

0

1d

0

0

2

0

0

Unknown

Adult Female 1 1 0 0 0

Juvenile Male 1 0 1e 0 0

Weaned pup Male

Female

2

2

1

0

0

0

0

0

1

2

Nursing pup Male

Female

Unknown

5

1

2

0

0

0

2f

0

0

1 

0

2h

2g

1

0
27

a One adult male was injured twice, first by March 22 and again November 24.

b Observed incident on Tern Island where an adult male harassed a weaned pup for 23 minutes. 

This pup sustained no obvious injuries.

c Observed incident on Trig Islet where an adult male harassed a pup that weaned 1–2 days 

previously. Although not overly aggressive, researchers intervened after 12 minutes of 

observation. The pup sustained no obvious injuries.

d Juvenile found dead on Tern islet by USFWS personnel February 22. Seal was last seen alive 

February 17 as emaciated and very green with algae on fur.

e Mummified carcass found on East Islet by USFWS personnel April 18.

f Two newborn pups were not seen alive; 1 at Whaleskate on April 30, and 1 at Trig on July 2.

g One pup disappeared from Trig between September 10 and October 19, when field effort was 

temporarily discontinued. The cause of the disappearance and weaning status is unknown.

h One newborn pup was never seen but was assumed born and lost between May 25–31, as 2 

females nursed a single pup for 3 weeks on Gin Islet. 
28

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29

CHAPTER 3. THE HAWAIIAN MONK SEAL ON

LAYSAN ISLAND, 2004

Karen Holman, Melinda Fowler, Catherine Gunther-Murphy
30
31

Laysan Island (lat. 25̊42'N, long. 171̊44'W) is located ca.1300 km northwest of Oahu in 

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

National Wildlife Refuge and the Papahānaumokuākea Marine National Monument, and is one 

of the six 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 2004, research was conducted by NMFS during April 24–August 5 

and September 30–October 2, and 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 2004 included (1) assessment of maternity 

and pup exchanges; and (2) documentation of male behavior, including aggression.

 

Censuses and Patrols 

 Censuses and patrols were scheduled to ensure that the entire island perimeter was 

monitored at least once daily during April 26–August 3. Censuses (n = 21) were conducted by 

two observers every fourth day from May 10 to August 1, beginning at 1300 Hawaii Standard 

Time and continuing for 2.3 to 3.5 h.

Standardized behavior patrols were conducted on noncensus days from May 12 to July 

26 to assess activity patterns of adults and large subadults and document male aggression. 

During these patrols (n = 18), observer 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 = 60) were conducted on noncensus and nonbehavior patrol 

days to record female and pup pairs, factors affecting survival, weaned pups, and molting 

animals. Additional partial island surveys were conducted as needed. 

Individual Identification 

A total of 273 individuals (237 excluding pups) were identified by existing or applied 

tags, bleach marks, scars or natural markings. Bleach marks were applied to 220 seals, including 

30 nursing pups. Most weaned pups (n = 33) were tagged with Temple Tags and 26 of these 

pups received PIT tags. In addition, 2 yearlings were newly tagged and 1 yearling was retagged 

with temple tags to replace a lost tag.
32

Collection of Samples

Sixty-two scat and 11 spew samples were collected. Skin punches were collected from 

31 weaned pups and 3 yearlings. Shed molt samples were collected from 26 individuals. 

Placentas were collected from 2 females. Necropsies were performed, and tissue samples 

collected from 1 recently dead pup, and skulls from 1 adult and 1 yearling carcass were also 

collected. Potentially entangling debris were collected from beaches and stored at secure sites 

around the island pending removal. Two pieces of debris were removed and collected from 

entangled animals (1 from a seal and 1 from a seabird). 

RESULTS 

Subpopulation Abundance and Composition 

The mean of 21 censuses was 103.4 seals (8.8 SD) including pups, and 81 seals (8.6 SD) 

excluding pups (Table 3.1). The total spring-summer subpopulation was 270 individuals, 234 

excluding pups (Table 3.2). This number is a subset of the total identified in the calendar year. 

The overall adult sex ratio was 0.9:1 (63 males: 70 females). The numbers of tagged known-age 

seals born at Laysan Island during the 1983–2003 period and resighted at any location in 2004 

are summarized in Table 3.3.

Reproduction 

At least 36 pups were born at Laysan Island in 2004: 34 were successfully weaned and 2 

died prior to weaning (Table 3.4a). Although 3 pups were still nursing at the end of camp, they 

all successfully weaned and were marked by USFWS personnel. Two of the 3 late-weaned pups 

were subsequently tagged (one in October 2004 and the other in April 2005). Nursing periods 

and measurements of weaned pups are summarized in Table 3.4b. The birth rate measured as the 

number of pups born divided by the number of adult-sized females in the subpopulation × 100 

was 51.4% ((36/70) × 100). A minimum of 13 pup exchanges occurred among 14 nursing 

females; one of these incidents was observed. One birth was also observed.

Interatoll Movement 

Interatoll movement was documented for 13 seals that completed a total of 17 

movements between Laysan Island and either French Frigate Shoals or Lisianski Island (Tables 

3.5a and b).
33

Factors Affecting Survival 

Attacks by large sharks, entanglement, emaciation, and other/unknown factors led to 14 

life-threatening conditions, which resulted in the death of 5 seals and the disappearance of 2 

other seals (Table 3.6). Three deaths were reported preseason by the FWS crew; a pup, a 

yearling, and an emaciated adult female. One neonate death occurred during the data collection 

period and a prematurely weaned pup died in December, after the field season. Three seals were 

entangled: 1 escaped unaided and 2 were released by observers. In addition to the incidents 

presented in Table 3.6, one probable large shark injury occurred between seasons and was 

observed as healed at the beginning of the season. Five 2-year- old seals were observed with an 

unusual fur condition that persisted throughout the season. The abnormality was characterized 

by matted, discolored fur mostly on the crown of the head and the dorsal posterior region. These 

animals did not appear otherwise compromised. 

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 The 

Oscar Elton Sette.
34

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35

TABLES

for Laysan Island
36
37

Table 3.1.--Summary statistics for censuses (n = 21) of Hawaiian monk seals at Laysan

Island from May 10 to August 1, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 46.9 4.4

Male 18.8 3.7

Female 26.6 2.9

Unknown 1.5 2.1

Subadults 19.3 5.9

Male 8.9 2.5

Female 9.8 4.7

Unknown 0.7 1.0

Juveniles 14.7 4.6

Male 7.1 2.6

Female 7.3 2.7

Unknown 0.2 0.5

Pups 22.4 2.5

Male 8.7 2.0

Female 13.1 1.9

Unknown 0.7 1.0

Non-pup total 81.0 8.6

Grand total 103.4 8.8
38

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

during the spring and summer of 2004. 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 70 0 133 0.9:1

Subadults 24 27 0 51 0.9:1

Juveniles 26 24 0 50 1.1:1

Pups 13 22 1 36 0.6:1

Non-pup total 113 121 0 234 0.9:1

Grand total 126 143 1 270 0.9:1
39

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

location in 2004.

Cohort year

Age

(years) Sex

Number 

originally tagged

Number 

resighted 

in 2004

1983 21 Male

Female

10

10

1

4

1984 20 Male

Female

16

13

2*

2

1985 19 Male

Female

16

14

2

2

1986 18 Male

Female

15

17

0

1

1987 17 Male

Female

13

15

3

3

1988 16 Male

Female

23

17

5*

2

1989 15 Male

Female

16

13

2

1

1990 14 Male

Female

7

9

2

2

1991 13 Male

Female

18

13

7

3

1992 12 Male

Female

18

14

2

3

1993 11 Male

Female

23

14

3

4

1994 10 Male

Female

18

29

7

7

1995 9 Male

Female

16

21

7

8

1996 8 Male

Female

23

21

7 

8 

1997 7 Male

Female

19

16

5

5
40

Cohort year

Age

(years) Sex

Number 

originally tagged

Number 

resighted 

in 2004

1998 6 Male

Female

Unknown

24

20

1

12

9 

0

1999 5 Male

Female

20

34

8

18 

2000 4 Male

Female

14

20

2

2

2001 3 Male

Female 

16

17 

7 

9 

2002 2 Male

Female 

21

16 

17

10 

2003 1 Male

Female 

10

18

9 

12 *

Cohort survivors include 2 seals removed from Laysan Island and translocated to the main 

Hawaiian Islands.
41

Table 3.4a.--Summary of Hawaiian monk seals born at Laysan Island in 2004.

Event

Number of pups

Male Female Unknown Total

Born 13 22 1 36

Died prior to weaning 0 1 1 2

Weaned 13a 21b 0 34a,b

Tagged 13a 20b 0 33a,b

a One male pup weaned after the end of the season and was tagged in October 2004.

b Two female pups weaned after the end of the season and were bleached by FWS. One of these 

2 pups was resighted and tagged in April 2005.

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

2004. 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 36.2 106.0 123.7

Standard deviation 4.4 8.4 5.9

n 30 30 30
42

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

locations in 2004, summarized by movements between two locations. No seals made more than 

one observed trip.

Original location Number of trips, size, and sex class

French Frigate Shoals 1 adult female

Lisianski Island 3 adult male

2 adult female

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

locations in 2004, summarized by movements between two locations. No seals made more than 

one observed trip.

Destination Number of trips, size, and sex class

Lisianski Island 3 adult male

6 adult female

1 subadult male

1 subadult female
43

Table 3.6.--Factors affecting Hawaiian monk seal survival at Laysan Island in 2004.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Adult Male 1 1 0 0

Juvenile Male 1 1 0 0

Mounting by Males

(none observed)

Entanglement

Subadult Male 1a 0 0 0

Weaned pup Male

Female

1b

1b

0

0

0

0

0

0

Emaciation

Adult Female 1 0 1c 0

Prematurely 

weaned pup 

Female 1 0 1c 0

Other/Unknown

Adult Female 1 0 0 1d 

Subadult Male 

Female 

1

1

1

1

0

0

0

0

Juvenile Male 1 0 1 0

Weaned pup Male 1 0 0 1e 

Nursing Pup Female

Unknown 

1

1

0

0

1f

1g

0

0

a

Seal disentangled itself and sustained no injuries from the entanglement.

b

Seal was released by researchers and sustained no injuries from the entanglement.

c

Both seals found dead and emaciated by FWS, the adult female had an estimated age of 19 

years, the prematurely weaned female pup also had seal-inflicted injuries.

d

A 21-year-old seal in extremely poor and deteriorating condition disappeared. This seal also 

suffered a partially severed hind flipper and a reopened mounting injury. e

Severely injured, possibly by boat propeller, in December 2004, seal disappeared by 1/3/2005.

f

Perinatal pup death.

g

Pup found dead by FWS within 4 days of birth, never confirmed to be alive.
44

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45

CHAPTER 4. THE HAWAIIAN MONK SEAL ON

LISIANSKI ISLAND, 2004

Ryan Jenkinson and Elizabeth Jenkinson
46
47

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

locations of the Hawaiian monk seal. The island is located ca. 1760 km northwest of Oahu (Fig. 

1.1) and is surrounded by Neva Shoal, a shallow reef bank within the Hawaiian Islands National 

Wildlife Refuge and the Papahānaumokuākea Marine National Monument (Fig. 4.1).

RESEARCH 

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

at Lisianski Island in 1980. In 2004, research was conducted by NMFS during April 24–August 

1, and incidental pelagic seal observations were recorded by fisheries observers near Lisianski 

Island on November 7–9. 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 2004 

included (1) assessment of maternity and pup exchanges; and (2) documentation of adult male 

behavior and aggression.

Censuses and Patrols 

Censuses and patrols were scheduled to ensure that the entire island was monitored at 

least once daily during April 24–August 1. Censuses (n = 24) were conducted by two observers 

every fourth day from April 30 to July 31, beginning at 1300 Hawaii Standard Time and 

continuing from 1.3 to 2.3 h. 

Standardized behavior patrols were conducted on noncensus days to assess activity 

patterns of adults and large subadults and document male aggression. During these patrols (n = 

23), 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 = 52) 

were conducted on non-census and nonbehavior patrol days from April 24 to July 30 to record 

female and pup pairs, factors affecting survival, weaned pups and molting animals. Additional 

partial island surveys were conducted as needed.

Individual Identification 

A total of 191 individuals (162 excluding pups) were identified by existing or applied 

tags, bleach marks, scars, or natural markings. All weaned pups (n = 29) were tagged with 

Temple Tags and 28 of these pups received PIT tags. 
48

Collection of Samples 

One-hundred one scats and 1 spew sample were collected. Skin punches were collected 

from 29 seals during tagging. One skull was collected from the mummified carcass of a fetus. 

Forty-two shed molt samples were collected from 42 individuals. Potentially entangling marine 

debris was collected from beaches and stored in a secure location pending removal. Four debris 

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

RESULTS

Subpopulation Abundance and Composition 

The mean of 24 censuses was 82.8 seals (10.3 SD) including pups, and 61.8 seals (8.5 

SD) excluding pups (Table 4.1). The total spring-summer subpopulation was 189 individuals, 

160 excluding pups (Table 4.2). This number is a subset of the total identified during the 

calendar year. The overall adult sex ratio was 1.2:1 (65 males:52 females). The numbers of 

tagged known-age seals born at Lisianski Island during the 1982–2003 period, and resighted at 

any location in 2004, are summarized in Table 4.3.

Reproduction 

A minimum of 29 pups were born at Lisianski Island in 2004 and all 29 were 

successfully weaned (Table 4.4a). One mummified fetus was found at the beginning of the field 

season and was not included in the pup total. 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 × 100 was 55.8% ((29/52) × 100). A 

minimum of 6 pup exchanges occurred among 7 nursing females. 

Interatoll Movement

Interatoll movement was documented for 13 seals that completed a total of 19 

movements between Lisianski Island and either FFS, Laysan Island or Pearl and Hermes Reef 

(Tables 4.5a and b).

Factors Affecting Survival 

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

in marine debris, and emaciation factors led to 10 life-threatening conditions, which resulted in 

the disappearance and probable death of one seal (Table 4.6). Five seals were observed 

entangled in marine debris: 1 escaped unaided and 4 were released by observers.
49

In addition to the cases summarized in Table 4.6, several other cases are noteworthy. 

Male harassment of weaned pups/juveniles was observed on 8 occasions. A minimum of 2 other 

weaned pups sustained minor dorsal scratches probably inflicted by other seals during 

unobserved incidents. One adult female seal displayed healed large shark bite scars on her left 

head and muzzle area that were not present on the animal in 2003. A mummified carcass of a 

seal fetus was found during the first full island patrol by which time the mother and date of death 

could not be determined.

 

 

ACKNOWLEDGMENTS

We thank the captain, officers, and crew of the NOAA Ship Oscar Elton Sette for 

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

Hawaiian Islands National Wildlife Refuge staff.
50

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51

TABLES

for Lisianski Island
52
53

Table 4.1.--Summary statistics for censuses (n = 24) of Hawaiian monk seals at Lisianski Island

from April 30 to July 31, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 45.8 7.7

Male 22.5 5.0

Female 21.8 3.9

Unknown 1.5 1.7

Subadults 8.1 2.7

Male 4.3 1.8

Female 3.8 1.5

Unknown 0.0 0.2

Juveniles 7.8 2.0

Male 4.8 1.5

Female 3.1 1.4

Unknown 0.0 0.0

Pups 21.0 2.9

Male 12.6 2.1

Female 8.4 1.7

Unknown 0.0 0.2

Non-pup total 61.8 8.5

Grand total 82.8 10.3
54

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

spring and summer of 2004. Includes all known parturient females and all pups born

during the calendar year.

Number of seals

Size Male Female Total

Sex ratio

male:female

Adults 65 52 117 1.2:1

Subadults 9 10 19 0.9:1

Juveniles 11 13 24 0.8:1

Pups 17 12 29 1.4:1

Non-pup total 85 75 160 1.1:1

Grand total 102 87 189 1.2:1
55

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

location in 2004.

Cohort year

Age

(years) Sex

Number originally 

tagged

Number resighted 

in 2004

1982 22 Male

Female

7

6

2

0

1983 21 Male

Female

6

18

1

7

1984 20 Male

Female

10

5

4

1

1985 19 Male

Female

5

9

1

0

1986 18 Male

Female

11

9

4

2

1987 17 Male

Female

12

6

1

1

1988 16 Male

Female

10

8

5

6

1989 15 Male

Female

–

--

–

--

1990 14 Male

Female

8

9

3

2

1991 13 Male

Female

9

6

4

2

1992 12 Male

Female

13

8

6

3

1993 11 Male

Female

4

9

2

2

1994 10 Male

Female

4

5

1

0

1995 9 Male

Female

7

10

2

2

1996 8 Male

Female

9

13

2

1
56

Cohort year

Age

(years) Sex

Number originally 

tagged

Number resighted 

in 2004

1997 7 Male

Female

10

9

4

3

1998 6 Male

Female

10

11

3

4

1999 5 Male

Female

16

11

3

2

2000 4 Male

Female

9

9

1

1

2001 3 Male

Female

5

9

1

1

2002 2 Male

Female

12

11

4

4

2003 1 Male

Female

12

14

9

11
57

Table 4.4a.--Summary of Hawaiian monk seals born at Lisianski Island in 2004.

Event

Number of pups

Male Female Total

Born 17 12 29

Died/Probably died prior to weaning 0 0 0

Weaned 17 12 29

Tagged 17 12 29

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

in 2004. 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 39.1 108.2 123.0

Standard deviation 4.2 10.5 7.1

n 13 23 23
58

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

locations in 2004, summarized by movements between two locations. No seals made

more than one observed trip.

Original location Number of trips, size, and sex class

Laysan Island 3 adult male

6 adult female

1 subadult male

 1 subadult female

Pearl and Hermes Reef 1 subadult male

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

locations in 2004, summarized by movements between two locations. No seals made

more than one observed trip.

Destination Number of trips, size, and sex class

FFS 1 adult male

Laysan Island 3 adult male

 2 adult female

Pearl and Hermes Reef 1 subadult male 
59

Table 4.6.--Factors affecting Hawaiian monk seal survival at Lisianski Island in 2004.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Juvenile Female 1 1a 0 0

Weaned pup Female 1 1b 0 0

Mounting by Male

Adult Female 1 1c 0 0

Weaned pup Male 1d 0 0 0

Entanglement

Adult Female 2e 0 0 0

Weaned pup Male

Female

2f 

1g

0

0

0

0 

0

0

Emaciation

Juvenile Female 1h 0 0 1j

a

Includes a seal with extensive yet almost healed injury. Injury occurred in early 2004. 

b

Weaned pup sustained a shark bite injury and was not observed as healed by the end of field 

data collection 2004.

c

Adult female observed with post-mounting injuries covering half the dorsum.

d

Adult male was observed mounting weaned male pup in shallow water. Intervention by another 

adult male prevented the pup’s imminent drowning.

e

One seal offshore, wrapped in floating debris, released self and the other seal, entangled with 

rope and floats, was released by observers.

f

Both seals were entangled around the neck, one with a plastic ring and the other with a strap. 

Both were released by observers.

g

Seal entangled with rope and line, released by observer.

h

Juvenile seal disappeared after it was observed as lethargic and emaciated.
60

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61

CHAPTER 5. THE HAWAIIAN MONK SEAL ON

PEARL AND HERMES REEF, 2004

Maire K. Cahoon, Jonathan C. Sprague, and Nicole M. Teeples
62
63

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

pupping locations of the Hawaiian monk seal. This atoll is located ca. 1900 km northwest of 

Oahu in the Northwestern Hawaiian Islands and is part of the Hawaiian Islands National Wildlife 

Refuge and the Papahānaumokuākea Marine National Monument (Fig. 1.1). Pearl and Hermes is 

composed of four vegetated and three 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 2004, research was conducted by NMFS on April 23 and 

during June 6–August 4. The perimeters of the four larger vegetated islets were divided into 

sectors using natural landmarks.

Censuses and Patrols 

Atoll censuses (n = 10) were conducted every fourth day, on average, from June 18 to 

August 4. All islets were censused on foot by one or two persons. In addition, incidental 

surveys were conducted opportunistically on noncensus days to resight seals tagged in previous 

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

Individual Identification 

A total of 231 individuals (196 excluding pups) were identified by existing or applied 

tags, scars or natural markings. Bleach marks were applied to 122 seals, including 1 nursing 

pup. Most weaned pups (n = 28) were tagged with Temple Tags and 27 of these pups received 

PIT tags. Six unknown adult seals (3 male, 3 female) were tagged with Temple Tags. One 

unknown adult female and 2 unknown subadults (1 male, 1 female) were tagged with Temple 

Tags and PIT tags. Twenty-two known adult seals (16 male, 6 female) and 1 known subadult 

male were retagged with Temple Tags. Ten known adult seals (7 males, 3 females) and 1 known 

subadult male were retagged with both Temple tags and PIT tags. 

Collection of Samples 

Seventy-one scat and five spew samples were collected. Skin punches were collected 

from 77 seals during tagging. Necropsies were performed and tissue and skeletal samples were 

collected from two dead seals. Shed molt samples were collected from 11 individuals. 

Potentially entangling marine debris was collected from beaches and stored in a secure location 

pending removal. 
64

RESULTS 

Subpopulation Abundance and Composition 

The mean of 10 atoll censuses was 90.0 seals (10.4 SD) including pups and 72.9 seals 

(8.5 SD) excluding pups (Table 5.1). The total summer subpopulation was 227 individuals, 192 

excluding pups (Table 5.2). This number is a subset of the total identified during the calendar 

year. The numbers of tagged known-age seals born at Pearl and Hermes Reef during the 1983–

2003 period, and resighted at any location in 2004, are summarized in Table 5.3.

Reproduction 

At least 35 pups were born at Pearl and Hermes Reef in 2004: 29 were successfully 

weaned, 4 were still nursing at the end of the research period, and 2 died before weaning (Table 

5.4). Nursing periods and measurements of weaned pups are summarized in Table 5.4. No pup 

switches were observed.

Interatoll Movement 

Interatoll movement was documented for 13 seals that completed a total of 20 

movements between Pearl and Hermes Reef and either Lisianski Island, Midway Atoll, or Kure 

Atoll (Tables 5.5a and b). 

Factors Affecting Survival 

Entanglement in marine debris and unknown factors resulted in seven life-threatening 

conditions (Table 5.6). One adult and two subadult seals were disentangled from debris. A 

possibly pregnant female was seen with a thin piece of line firmly secured around its neck. 

Attached to the line was a small bundle (12 in × 6 in) of debris consisting of various pieces of net 

and line. We were unable to remove the line and did not resight this individual during the field 

season. In addition to incidents presented in Table 5.6, a prematurely weaned female pup was 

last observed on July 9 and likely did not survive.

ACKNOWLEDGMENTS

We thank the captain, officers, and crew of the NOAA Ship Oscar Elton Sette. We also 

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

Wildlife Refuge staff. Many thanks to PIFSC Coral Reef Ecosystem Division and the F/V 

Casitas for assistance in removal of debris on islands.
65

TABLES

for Pearl and Hermes Reef
66
67

Table 5.1.--Summary statistics for atoll censuses (n = 10) of the Hawaiian monk seal at Pearl and

Hermes Reef from June 18 to August 4, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 49.4 5.1

Male 20.7 3.4

Female 22.8 4.3

Unknown 5.9 2.0

Subadults 14.1 2.6

Male 6.2 2.1

Female 6.3 1.6

Unknown 1.6 1.0

Juveniles 9.4 3.0

Male 4.8 2.1

Female 4.0 1.2

Unknown 0.6 1.0

Pups 17.1 3.1

Male 7.6 2.5

Female 6.8 2.8

Unknown 2.7 2.1

Non-pup total 72.9 8.5

Grand total 90.0 10.4
68

Table 5.2.--Composition of the Hawaiian monk seal subpopulation at Pearl and Hermes Reef

during the spring and summer of 2004. 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 68 69 2 139 1.0:1

Subadults 15 16 0 31 0.9:1

Juveniles 11 11 0 22 1.0:1

Pups 16 15 4 35 1.1:1

Non-pup total 94 96 2 192 1.0:1

Grand total 110 111 6 227 1.0:1
69

Table 5.3.--Summary of tagged known-age seals born at Pearl and Hermes Reef and resighted 

at any location in 2004.

Cohort year

Age

(years) Sex

Number originally 

tagged

Number resighted 

in 2004

1983 21 Male

Female

8

2

0

1

1984 20 Male

Female

5

8

1

2

1985 19 Male

Female

9

6

2

3

1986 18 Male

Female

Unknown

10

7

1

2

2

0

1987 17 Male

Female

14

7

3

2

1988 16 Male

Female

12

6

7

3

1989 15 Male

Female

8

6

1

0

1990 14 Male

Female

5

1

3

0

1991 13 Male

Female

10

11

5

3

1992 12 Male

Female

13

10

5

7

1993 11 Male

Female

14

7

3

3

1994 10 Male

Female

--

--

--

--

1995 9 Male

Female

15

12

7

4

1996 8 Male

Female

11

12

2

3

1997 7 Male

Female

16

11

6

3
70

Cohort year

Age

(years) Sex

Number originally 

tagged

Number resighted 

in 2004

1998 6 Male

Female

8

21

4

12

1999 5 Male

Female

11

15

3

5

2000 4 Male

Female

12

10

5

3

2001 3 Male

Female

16

9

2

2

2002 2 Male

Female

16

6

2

2

2003 1 Male

Female

14

10

8

7
71

Table 5.4a.--Summary of Hawaiian monk seals born at Pearl and Hermes Reef in 2004.

Event

Number of pups

Male Female Unknown Total

Born 16 15 4 35

Died prior to weaning 0 2 0 2

Still nursing 0 0 4 4

Weaned 16 13 0 29

Tagged 16 12* 0 28*

*A prematurely weaned female pup was last seen on July 9 and disappeared before tagging.

Table 5.4b.--Summary of nursing periods and measurements of weaned pups at Pearl and 

Hermes Reef in 2004. All measurements were taken within 2 weeks after weaning. 

Nursing period (d) Axillary girth (cm) Straight dorsal length 

(cm)

Mean 36.5 100.1 124.2

Standard deviation 7.1 10.0 6.1

n 2 12 12
72

Table 5.5a.--Documented movement of Hawaiian monk seals to Pearl and Hermes Reef from 

other locations in 2004, summarized by movements between two locations. No seals made more 

than one observed trip.

Original location Number of trips, size, and sex class

Lisianski Island 1 subadult male

Midway Atoll 3 adult male

3 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 2004, summarized by movements between two locations. One seal made more 

than one observed trip.

Destination Number of trips, size, and sex class

Lisianski Island 1 subadult male

Midway Atoll 5 adult male

3 adult female

1 juvenile male

Kure Atoll 1 adult male

1 adult female
73

Table 5.6.--Factors affecting Hawaiian monk seal survival at Pearl and Hermes Reef in 2004.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

(none observed)

Mounting by Males

(none observed)

Entanglement

Adult Female 2ab 0 0 0

Subadult Male 1a 0 0 0

Juvenile Male 1a 0 0 0

Unknown

Adult Female 1 0 1 0

Nursing pup Female 2 0 2 0

a

Seal released by observers.

b

Observers unable to remove entanglement; seal was not resighted.
74

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75

CHAPTER 6. THE HAWAIIAN MONK SEAL ON

MIDWAY ATOLL, 2004

Leona Laniawe and Albert L. Harting
76
77

Midway Atoll (lat. 28̊14'N, long. 177̊22'W) is one of the primary haulout and pupping 

locations of the endangered Hawaiian monk seal. This atoll is located ca. 2100 km northwest of 

Oahu in the Northwestern Hawaiian Islands within the Midway Atoll National Wildlife Refuge 

and the Papahānaumokuākea Marine National Monument (Fig. 1.1) and comprises a circular 

atoll approximately 9 km in diameter, enclosing a lagoon and three permanent islets (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) maintained an overlay refuge at 

the site since 1988, until full authority was transferred to the USFWS in October 1996. 

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 

1997–1999 by collaborating researchers from Oceanic Society (OS) and Hawaii Wildlife Fund. 

In 2004, research was conducted by NMFS during January 29–August 5. Incidental observations 

were recorded by USFWS personnel during the rest of the year. Perimeters of the three 

permanent islets were divided into sectors using artificial or natural landmarks. Research 

objectives specific to this subpopulation in 2004 included (1) assessment of maternity and pup 

exchanges; and (2) monitoring human impacts on seals to quantify occurrence and potential 

effects on monk seal habitat usage.

Censuses and Patrols 

Atoll censuses (n = 26) were conducted every seventh day, on average, from January 29 

to August 2. All islets were censused on foot by one or two persons. Patrols of Sand Island (n = 

15), Eastern (n = 15), or Spit (n = 15) were conducted on non-atoll census days during January 

29–August 5. 

Individual Identification 

A total of 76 individuals (57 excluding pups) were identified by existing or applied tags, 

bleach marks, scars or natural markings. Most weaned pups (n = 13) were tagged with Temple 

tags and PIT tags. One prematurely weaned pup was not tagged and later disappeared. 

Collection of Samples

Skin punches were collected from 13 weaned pups during tagging. Three scats and 3 

shed molt samples were collected. One necropsy was performed and tissue samples were 

collected. Potentially entangling marine debris were collected from beaches and either destroyed 

at Midway or stored in a secure location pending removal.
78

Noteworthy Events

Beach Monitoring and Public Education

From January to August 2004, Sand Island beaches were monitored to limit human 

impacts and disturbance on seals. Monk seal natural history was shared opportunistically with 

visitors and residents. On three occasions, NMFS observer intervention prevented the probable 

disturbance of resting monk seals; one involved persons violating refuge rules in the presence of 

a mother/pup pair. Other actions taken to mitigate disturbance to seals included the posting of 

seal signs approximately 50 yards away from seals informing people of the animal’s presence in 

public access areas. On Sand Island, through cooperation with the USFWS, a section of a public 

beach was temporarily closed to limit disturbance to a mother and pup pair. In addition, FWS 

orientation presentations for new personnel and visitors include seal natural history, NMFS 

recovery efforts, and address refuge rules governing seal viewings and beach closures. 

RESULTS

Subpopulation Abundance and Composition 

The mean of 26 atoll censuses was 24.8 seals (5.9 SD) including pups, and 19.3 seals (5.2 

SD) excluding pups (Table 6.1). The total spring-summer subpopulation was 62 seals, 45 

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 1988–2003 period, and 

resighted at any location in 2004, are summarized in Table 6.3.

Reproduction 

A minimum of 17 pups were born at Midway Atoll in 2004; 14 were successfully weaned 

(Table 6.4a), 2 were found dead, and 1 was still nursing at the end of the field season. The birth 

rate, measured as the number of pups born divided by the number of adult-sized females in the 

subpopulation × 100 was 73.9% ((17/23) × 100). A minimum of one pup exchange occurred 

between nursing females, resulting in one prematurely weaned pup. Nursing periods and 

measurements of weaned pups are summarized in Table 6.4b.

Interatoll Movement 

Interatoll movement was documented for 19 seals that completed a total of 31 

movements between Midway Atoll and either Pearl and Hermes Reef or Kure Atoll (Tables 6.5a 

and b).
79

Factors Affecting Survival 

Other/unknown causes led to 7 life-threatening conditions (Table 6.6). Two pups were 

found dead early in the season. One pup carcass was found on Eastern Island and the other was 

found floating in shallow water off of Spit Island. Both carcasses were in fresh to semi-fresh 

condition (one was necropsied at Midway and the other in Honolulu). In addition, a third pup 

disappeared and probably died after she was prematurely weaned due to a pup exchange. 

Another pup was injured, possibly by a shark, and was thin and in deteriorating condition when 

last seen in November.

ACKNOWLEDGMENTS 

We acknowledge the support of the U.S. Fish and Wildlife Service. Special thanks are 

extended to John Klavitter, Refuge Biologist; Mike Johnson, Assistant Refuge Manager; and 

Island residents that expressed interest and cooperation in Midway Atoll Hawaiian monk seal 

recovery efforts. We also thank the officers and crew of the NOAA Ship Oscar Elton Sette for 

logistical assistance. 
80

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81

TABLES

for Midway Atoll
82
83

Table 6.1.--Summary statistics for atoll censuses (n = 26) of Hawaiian monk seals at Midway

Atoll from January 29 to August 2, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 15.3 4.2

Male 5.4 2.5

Female 8.8 2.8

Unknown 1.2 1.3

Subadults 1.8 0.9

Male 1.0 0.6

Female 0.7 0.5

Unknown 0.0 0.2

Juveniles 2.2 1.3

Male 0.9 0.8

Female 1.2 0.8

Unknown 0.1 0.3

Pups 5.5 4.7

Male 1.0 1.3

Female 1.7 2.2

Unknown 2.8 2.7

Non-pup total 19.3 5.2

Grand total 24.8 5.9
84

Table 6.2.--Composition of the Hawaiian monk seal subpopulation at Midway Atoll during the

spring and summer of 2004. 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 15 23 0 38 0.6:1

Subadults 2 1 0 3 2.0:1

Juveniles 2 2 0 4 1.0:1

Pups 5 11 1* 17* 0.5:1

Non-pup total 18 27 0 45 0.7:1

Grand total 24 37 1 62 0.6:1

*Includes a pup that was still nursing when the field camp ended.

 
85

Table 6.3.--Summary of tagged known-age seals born at Midway Atoll and resighted at any

location in 2004.

Cohort year

Age

(years) Sex

Number 

originally tagged

Number 

resighted 

in 2004

1988 16 Male

Female

0

1

NA

1

1989 15 Male

Female

0

0

NA

NA

1990 14 Male

Female

0

0

NA

NA

1991 13 Male

Female

1

1

1

1

1992 12 Male

Female

0

1

NA

1

1993 11 Male

Female

1

0

0

NA

1994 10 Male

Female

0

0

NA

NA

1995 9 Male

Female

Unknown

1

6

1

0

1

0

1996 8 Male

Female

1

4

0

0

1997 7 Male

Female

3

6

1

2

1998 6 Male

Female

8

2

3

1

1999 5 Male

Female

7

4

2

1

2000 4 Male

Female

5

9

1

0

2001 3 Male

Female

6

5

1

2

2002 2 Male

Female

7

4

1

2

2003 1 Male

Female

5

9

1

3
86

Table 6.4a.--Summary of Hawaiian monk seals born at Midway Atoll in 2004.

Event

Number of pups

Male Female Unknown Total

Born 5 11 1 17

Died prior to weaning 0 2 0 2

Still nursing 0 0 1 1

Weaned 5 9 0 14

Tagged 5 8* 0 13

*A prematurely weaned female pup was not tagged. This pup later disappeared.

Table 6.4b.--Summary of nursing periods and measurements of weaned pups at Midway Atoll in 

2004. 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 39.0 110.6 128.0

Standard deviation -.- 5.9 7.5

n 1 12 12
87

Table 6.5a.--Documented movement of Hawaiian monk seals to Midway Atoll from other 

locations in 2004, summarized by movements between two locations. Three seals made more 

than one observed trip.

Destination Number of trips, size, and sex class

Pearl and Hermes Reef 5 adult male

3 adult female

1 juvenile male

Kure Atoll 2 adult male

6 adult female

1 weaned male pup

1 weaned female pup

Table 6.5b.--Documented movement of Hawaiian monk seals from Midway Atoll to other 

locations in 2004, summarized by movements between two locations. No seals made more than 

one observed trip.

Destination Number of trips, size, and sex class

Pearl and Hermes Reef 3 adult male

3 adult female

Kure Atoll 2 adult male

3 adult female

 1 juvenile female
88

Table 6.6.--Factors affecting Hawaiian monk seal survival at Midway Atoll in 2004.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

(none observed)

Mounting by Males

(none observed)

Entanglement

(none observed)

Other/Unknown

Adult Female 3 3 0 0

Weaned pup Female 1 1a 0 0

Prematurely 

weaned pup

Female 1b 0 0 1

Nursing pup Female 2 0 2 0

a The pup was injured, possibly by a shark, and was thin and in deteriorating condition when last 

seen in November.

b The pup disappeared and probably died after she was prematurely weaned due to a pup 

exchange.
89

CHAPTER 7. THE HAWAIIAN MONK SEAL AT

KURE ATOLL, 2004

Tracy A. Wurth and Robert D. Marshall
90
91

Kure Atoll (lat. 28̊25'N, long. 178̊10'W) is one of the primary haulout and pupping 

locations of the Hawaiian monk seal. The atoll is located ca. 2300 km northwest of Oahu in the 

Northwestern Hawaiian Islands (Fig. 1.1) and is a seabird sanctuary of the State of Hawaii within 

the Papahānaumokuākea Marine National Monument. The atoll consists of a circular fringing 

reef approximately 9 km in diameter, the enclosed lagoon, one permanent vegetated island 

(Green Island), two 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. 

RESEARCH 

NMFS began research on the Hawaiian monk seal at Kure Atoll in 1981. In 2004, 

research was conducted by NMFS from June 9 to August 2, and additional incidental 

observations were recorded by State of Hawaii personnel until August 30. The perimeter of 

Green Island was divided into eight sectors using artificial or natural landmarks. 

Censuses and Patrols

Atoll censuses (n = 11) were conducted every fourth day on average, from June 17 to 

July 29. All islets were censused on foot by one or two persons. Shark Islet and Stark Reef were 

not emergent during the 2004 field season. Patrols were conducted on non-atoll census days to 

identify seals and monitor locations used by parturient females. In total, 31 patrols of Green 

Island and 1 patrol of Sand Islet were conducted. Full island standardized incidental surveys of 

Green Island (n = 7) were conducted on non-atoll and non-patrol days between June 10 and 

August 2 to record females with nursing pups, weaned pups, juveniles, molting animals, and sick 

or injured seals. Additional partial island surveys of Green Island were conducted as needed. 

Individual Identification

A total of 108 individuals (88 excluding pups) were identified by existing or applied tags, 

bleach marks, scars or natural markings. All weaned pups (n = 20) were tagged with Temple 

Tags, and 18 of these pups received PIT tags. 

Collection of Samples

Forty-one scat, 2 spew, and 27 molt samples were collected. Skin punches were 

collected from 18 seals during tagging. Potentially entangling marine debris was collected from 

the beaches on Green and Sand Islands and stored in a secure location pending removal. A large 
92

conglomerate of buried net remains at the site of the Paradise Queen II wheel house, the remains 

of a wreck on the east shore of Green Island. 

Noteworthy Events

Aggression Towards Weaned Pups

One incident of targeted, male aggression towards weaned pups was observed in 2004. 

Two female weaned pups and 1 juvenile male were observed interacting together in shallow 

water. Two of the 3 seals (1 weaned pup and 1 juvenile) were harassed, bitten, and held 

underwater by an adult male that swam into the area. The incident was eventually disrupted by 

researchers. The event did not result in obvious injuries to any of the animals involved and no 

further aggression was observed.

RESULTS

Subpopulation Abundance and Composition 

The mean of 11 atoll censuses was 50.1 seals (11.3 SD) including pups, and 39.8 seals

(9.0 SD) excluding pups (Table 7.1). The total spring-summer subpopulation was 106 

individuals, 86 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 1981–2003 

period, and resighted at any location in 2004, are summarized in Table 7.3.

Reproduction

At least 20 pups were born at Kure Atoll in 2004, and all successfully weaned (Table 

7.4a). All 20 pups were born prior to the time NMFS research began on June 9. 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 × 100 was 50.0% (20/40 

×100). Six of the 8 identified parturient females (75%) had been temporarily maintained as pups 

in the Kure Atoll Head Start Project between the years of 1984 and 1991. Three documented 

pup exchanges occurred in the 2004 season.

Interatoll Movement 

Interatoll movement was documented for 15 seals that completed a total of 19 

movements between Kure Atoll and either Pearl and Hermes or Midway Atolls (Tables 7.5a and 

b).
93

Factors Affecting Survival

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

entanglement in marine debris resulted in 6 life-threatening conditions, which lead to the 

probable death of 1 seal (Table 7.6). Three seals were observed entangled in marine debris. 

Two of the seals were disentangled by researchers with no evident complications. Two attempts 

were made to disentangle the third seal, but with only partial success, and the seal ultimately 

freed itself from the debris. One large shark bite was observed on a weaned pup. The seal 

suffered a large and severe bite to the top of the head and neck, and subsequently disappeared 

and probably died. In addition to the incidents in Table 7.6, an emaciated adult female was 

observed in late July on Sand Islet. No other obvious injuries were evident and the seal was not 

seen again before the end of the field season on August 5, but was resighted alive the following 

year.

ACKNOWLEDGMENTS

We acknowledge the support of the State of Hawaii, Department of Land and Natural 

Resources and Division of Forestry and Wildlife. Special thanks are extended to Cynthia 

Vanderlip, DNLR staff. We thank the captain and crew of the NOAA Ship Oscar Elton Sette 

for logistical support. We also thank the NMFS Coral Reef Ecosystem Division marine debris 

team for their hard work and assistance in removing derelict fishing gear from Green Island and 

within Kure Atoll.
94

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95

TABLES

for Kure Atoll
96
97

Table 7.1.--Summary statistics for atoll censuses (n =11) of Hawaiian monk seals at Kure 

Atollfrom June 17 to July 29, 2004.

Size/Sex Mean number of individuals Standard deviation

Adults 32.0 7.2

Male 11.3 3.1

Female 16.9 4.2

Unknown 3.8 2.5

Subadults 3.2 1.5

Male 2.4 0.9

Female 0.3 0.5

Unknown 0.5 0.8

Juveniles 4.6 1.4

Male 3.2 1.2

Female 1.5 0.9

Unknown 0.0 0.0

Pups 10.3 3.3

Male 4.9 1.5

Female 5.0 2.3

Unknown 0.4 0.5

Non-pup total 39.8 9.0

Grand total 50.1 11.3
98

Table 7.2.--Composition of the Hawaiian monk seal subpopulation at Kure Atoll during the 

springand summer of 2004. Includes all known parturient females and pups born during the 

calendar year.

Number of seals

Size Male Female Total

Sex ratio

male:female

Adults 33 40 73 0.8:1

Subadults 3 1 4 3.0:1

Juveniles 6 3 9 2.0:1

Pups 9 11 20 0.8:1

Non-pup total 42 44 86 1.0:1

Grand total 51 55 106 0.9:1
99

Table 7.3.--Summary of tagged known-age seals born at Kure Atoll and resighted at any location 

in 2004.

Cohort year Age

(years) Sex

Number 

originally tagged

Number 

resighted

in 2004

1981 23 Male

Female

3

5

0

0

1982 22 Male

Female

1

3

0

1

1983 21 Male

Female

4

0

2

NA

1984 20 Male

Female

4

2

0

2

1985 19 Male

Female

2

3

0

1

1986 18 Male

Female

1

0

0

NA

1987 17 Male

Female

1

3

1

2*

1988 16 Male

Female

2

5

2

2

1989 15 Male

Female

5

4

1

1

1990 14 Male

Female

3

3

0

1

1991 13 Male

Female

7

6

4

3*

1992 12 Male

Female

5

8

3

5

1993 11 Male

Female

9

4

5

2

1994 10 Male

Female

3

0

0

NA

1995 9 Male

Female

6

5

3

2
100

Cohort year Age

(years) Sex

Number 

originally tagged

Number 

resighted

in 2004

1996 8 Male

Female

10

6

3

0

1997 7 Male

Female

9

7

1

2

1998 6 Male

Female

17

6

5

2

1999 5 Male

Female

8

13

2

2

2000 4 Male

Female

5

8

1

0

2001 3 Male

Female

4

13

0

0

2002 2 Male

Female

11

 7

3

0

2003 1 Male

Female

8

10

4

2

*Cohort survivors include two seals removed from Kure Atoll for rehabilitation and released at 

either Kure or Midway Atoll.
101

Table 7.4a.--Summary of Hawaiian monk seals born at Kure Atoll in 2004.

Event

Number of pups

Male Female Total

Born 9 11 20

Died prior to weaning 0 0 0

Weaned 9 11 20

Tagged 9 11 20

Table 7.4b.--Summary of nursing periods and measurements of weaned pups at Kure Atoll 

in2004. Nursing periods were calculated where both birth and weaning date ranges were < 4 d. 

All measurements were taken within 2 weeks after weaning. All pups were born prior to 

researchers’ arrival on island. 

Nursing period (d) Axillary girth (cm)

Straight dorsal length 

(cm)

Mean - 114.9 135.9

Standard deviation - 13.3 8.6

n - 8 8
102

Table 7.5a.--Documented movement of Hawaiian monk seals to Kure Atoll from other locations 

in 2004, summarized by movements between two locations. No seals made more than one 

observed trip.

Original location Number, size, and sex class

Midway Atoll 2 adult male

3 adult female 

1 juvenile male

Pearl and Hermes Reef 1 adult female

1 adult male

Table 7.5b.--Documented movement of Hawaiian monk seals from Kure Atoll to other locations 

in 2004, summarized by movements between two locations. No seals made more than one 

observed trip.

Destination Number, size, and sex class

Pearl and Hermes Reef 1 adult female

Midway Atoll 2 adult male

6 adult female

1 male weaned pup

1 female weaned pup
103

Table 7.6.--Factors affecting Hawaiian monk seal survival at Kure Atoll in 2004.

Outcome

Size Sex Total Injured Died Probably died

Attack by Large Shark

Weaned pup Female 1a 0 0 1

Mounting by Males

Weaned pup Female 1b 0 0 0

Juvenile Male 1b 0 0 0

Entanglement

Weaned pup Male 2c,d 0 0 0

Adult Female 1e 0 0 0

a Large shark bite to the top of head and neck. Seal disappeared.

b Adult male aggressor harassed, bit, and held the two seals underwater. The incident was 

 disrupted by observers.

c Seal released by observers.

d Seal found with eel cone stuck on muzzle. Seal was released by observers.

e Seal had piece of net entangled around its neck. Several attempts were made to disentangle the 

 seal. The seal eventually disentangled itself.
104

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105

CHAPTER 8. THE HAWAIIAN MONK SEAL ON

NIHOA ISLAND, 2004

Maire Cahoon, Charles Littnan, and Thea Johanos
106
107

Nihoa Island (lat. 23̊04'N, long. 161̊55'W) and Necker Island (lat. 23̊36'N, long. 

164̊42'W) are located ca. 450 and 750 km, respectively, northwest of Oahu in the Northwestern 

Hawaiian Islands (Fig. 1.1). These islands lie within the Hawaiian Islands National Wildlife 

Refuge. 

RESEARCH 

In 2004, the National Marine Fisheries Service collected data at Nihoa Island on August 

13. Necker was not visited in 2004. The perimeter of Nihoa Island was divided into 3 sectors 

using natural landmarks (Fig. 8.1). In 2004, research objectives specific to the Nihoa Island 

included assessment of pup production and the extent of migration between French Frigate 

Shoals and this location.

Censuses and Patrols 

One entire island survey was conducted at Nihoa in 2004; a beach count of all haulout

sites was conducted by two observers on August 13, beginning at 0930 Hawaii Standard Time 

and continuing for approximately 4.5 h. 

Individual Identification

On Nihoa Island, one seal was identified by tag as a 5-year-old male born at Nihoa 

Island in 1999. In total, 3 tagged seals were noted; 2 seals were observed with 1 red tag each (1 

identified and 1 unidentified), and 1 unidentified seal was observed with a broken yellow tag, 

indicating that it was originally tagged at FFS.

Collection of Samples 

No samples were collected at Nihoa Island in 2004. 

RESULTS

Subpopulation Abundance and Composition 

The census total for counts conducted on Nihoa Island was 34 seals (28 excluding pups) 

on August 13. Because of limited effort, the composition of the spring-summer subpopulation 

was not determined. 

 
108

Reproduction 

At least 6 pups (all of unknown sex) were born at Nihoa Island in 2004; 4 nursing pups 

and 2 weaned pups were observed at Nihoa Island on August 13.

Interatoll Movement 

Interatoll movement was not documented for seals observed at Nihoa Island in 2004.

Factors Affecting Survival 

Factors affecting survival were not observed at Nihoa Island in 2004. 

ACKNOWLEDGMENTS 

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

National Wildlife Refuge staff, and the captain, officers, and crew of the NOAA Ship Oscar 

Elton Sette for logistical assistance.
109

REFERENCES
110
111

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 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.

Goodman-Lowe, G. D. .

1998. Diet of the Hawaiian monk seal status (Monachus schauinslandi) from the 

Northwestern Hawaiian Islands during 1991 to 1994. Mar. Biol. 132:535-546. 

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., 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.

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.
112

(This page is left blank intentionally.)
APPENDIXES

Appendix A.—Reports summarizing annual field research on the Hawaiian monk seal by the National Marine 

Fisheries Service and collaborating scientists.

A-1

All islands

Johanos, T. C., and J. D. Baker (Eds.).

2007. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 2003. U.S. 

Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-9, 116 p.

Johanos, T. C., and J. D. Baker (Eds.).

2005. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 2002. U.S. 

Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-1, 115 p.

Johanos, T. C., and J. D. Baker (Eds.).

2004. The Hawaiian monk seal in the Northwestern Hawaiian Islands, 2001. U.S. 

Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-1, 134 p.

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, 100 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.
Appendix A.—Continued.

A-2

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.

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-TM-NMFS-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-TM-NMFS-SWFC118, 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.

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-TM-NMFS-SWFC-49, 65 p.
Appendix A.—Continued.

A-4

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.

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-NMFS-SWFSC-182, 29 

p.
Appendix A.—Continued.

A-5

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-SWFSC-155, 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-TM-NMFS-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-TM-NMFS-SWFC-123, 37 p.

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.
Appendix A.—Continued.

A-6

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.
Appendix B.—Hawaiian monk seal census form and 2004 census form directions.

(See following pages.)

B-1
B-2
B-3

2004

CENSUS FORM DIRECTIONS

(Unabridged - Laysan and Lisianski Islands)

This form is used to record all Hawaiian monk seal and green turtle sightings. Turtle sightings are recorded only 

during census activities (not during patrols), unless noteworthy event occurs (turtle injured, tagged, tumored, mating, 

etc.). On the census form, all data that can be recorded for seals can also be recorded for turtles (although this 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 size/sex class at the bottom of the page.

All original data should be coded in pencil. Never erase data once you have left the recording site. Instead, cross 

errors out with a single line so that the original information can still be read. Field editing is editing before running 

the data entry and checking program. All field editing by the data collector should be in blue, and field editing by 

others should be in red. As soon as you begin the entry and checking program, the computer will assign the 

computer page number and display it on the screen. At this point, be sure to fill it in on your census form. All 

editing after this point should be in orange. After completing the entry and checking program, check off and initial 

the ENTERED box on the census form.

A separate data sheet should be filled out for each date, observer, data type, and island within an atoll. If no seals 

are present, you should still fill out the information at the top of the census form and write "No seals" in the data 

area (only enter the header information). If the island itself is not present, indicate this by entering the header 

information and the first line (using 99 for the sector code and leaving the rest of the line blank). To save paper, 

you should use a census form with multiple headers if you only have a few seals to record (i.e., at some islands 

within an atoll, or when recording incidental sightings before or after census or patrol). In essence, on a census form 

with multiple headers, each header and its associated lines represents a separate data sheet. 

If two people conduct the census, they should have the same weather and the same begin and end time (i.e., both 

begin at the same time and place, and proceed in opposite directions until they meet on the other side of the island or 

islet) and combine pages into one set. Patrols may be conducted by more than one observer, but page sets are not 

combined, and header information may differ between page sets. Patrol observers should attempt to start at roughly 

the same time. The sum of all observers' patrol activity for a day should result in one complete island count.

Always record disturbance. You must be honest about this! Fill out a census form to document disturbance if you 

disturb a seal when you are not otherwise collecting data. On a census or atoll count, it is also assumed that 

condition and molt data will be taken. 

Do not make up additional codes. If the need for an additional code arises, contact Honolulu.
B-4

PAGE HEADER

DATA TYPE

C = Census: A complete, timed count on an island begun around 1300. Census is conducted as 

quickly as possible (while gathering all information). Data collected on all seals and turtles. Complete 

data are recorded, including size, sex, condition, ID, and disturbance. Associations are assumed to be 

coded for all seals. In 2004 at Laysan and Lisianski Islands, record spatial and pair associations and 

paired male-male contests involving adult and S4 seals, otherwise code behavior X (data not taken). 

A = Atoll-wide census (must be completed within 2 consecutive days). Data collected on all seals and 

turtles.

B = Behavior patrol: A complete, untimed count where size, sex, ID and disturbance are recorded. 

Associations are assumed to be coded for all seals. In 2004 at Laysan and Lisianski Islands, record 

spatial and pair associations and paired male-male contests involving adult and S4 seals, otherwise code 

behavior X (data not taken). Record turtles only if noteworthy observation.

P = Patrol: A complete, untimed count where size, sex, ID and disturbance are recorded. Behavior 

data is not taken. Record turtles only if noteworthy observation.

I = Incidental observation. In this data type, null fields are interpreted as "data not recorded", so code 

data explicitly. If numbered, this indicates a full island incidental with year-specific goals. At Laysan 

and Lisianski Islands in 2004, these surveys will record mother-pup pairs, weaned pups, molters, 

survival factors (including severe harassments and mobbings) and other noteworthy observations. 

T = Tag status entry (to record that a given tag is now inactive/not on a seal). Record tag status (found 

or recovered) in notes columns. 

COMPUTER PAGE NO. Leave this blank during data collection. It will be assigned and displayed on the 

screen when you enter the data. At that time, be sure to fill in the computer page number on your census 

form, as this number is needed for data retrieval.

PAGE Page number within a census or patrol. For example, if the census (or patrol) requires three pages, then 

mark the first page as "page 1 of 3" and so on. If more than 1 person conducts the census, then combine 

page numbers; person A has pages 1 and 2, while person B has pages 3 and 4 of a four-page census day. 

The maximum number of pages in a set is 9. Header information (time begin/end, date, number, and 

weather) should be the same for all pages within a set.

ISLAND Name of island and atoll, e.g., East, FFS. 

OBSERVER Three initials. If no middle initial, use the first and last block. 

TIME BEGIN and END On a 24-h clock, e.g., 6 p.m. = 1800, for the group of pages. Midway uses Midway time, 

all other sites use Hawaii Standard time.

DATE The date that data are collected (in YYYYMMDD format).

NUMBER Censuses, Atoll counts, Behavior patrols, and Patrols must be numbered. Each data type will have its 

own 3 digit number series, starting with 001. For data types other than A, have a separate number series 

for each islet within an atoll.
B-5

Weather information (except temperature) should be a summary of the entire day up until the end of the census 

or patrol, not merely an instantaneous observation. Temperatures taken in the morning are not representative 

for the period of data collection.

TEMP. Temperature in degrees Celsius at beginning of census or patrol.

WIND Speed:0 = no wind, calm (<5 knots)

1 = light breeze (5-15 knots)

2 = strong wind (>15 knots)

Direction:NN,NE,EE,SE,SS,SW,WW,NW

Thus, 2 N N = strong wind from north 

CLOUD Cloud cover: 00 = no clouds

01-09 = 10 to 90% cover

10 = 100% cover

PREC. Precipitation: 0 = no precipitation or trace

1 = mist/drizzle

2 = rain

3 = intermittent rain

LINES

CONTINUE If the same seal sighting is recorded on several lines for any reason (e.g., additional tag or 

association, behavior at a later time, change of beach position, or photos), put the original line 

number you are continuing from here. Lines may be continued only within the same page. Fill in 

the original line as completely as possible. During entry, the data in all fields from TIME through 

MOLT must be copied from the original line if left blank on the continuation line. Do not copy 

other fields after MOLT (see entry directions for more information). Several lines can have the 

same continuation line number. 

Make a new original line (i.e. do not use continuation lines) for a seal each time that you come 

abreast of it on census or patrol. This is important because beach position on the original line 

determines if a seal is counted on census (if the seal is ashore it will be counted). When recording 

paired male-male contests (at Laysan and Lisianski Islands in 2004), record contests as you see 

them ahead of you (within 30 m). When you come abreast of the seal, record the beach position 

and time and make this your original line. All previously recorded lines for this sighting will be 

reverse continuation lines.

TIME The time should be recorded for each seal sighting, on a 24-h clock

SECTOR Location on island (e.g., 1-20 on Laysan)

Special codes as follows:

00 = unknown sector (use also for areas without sectors, i.e. middle of the lagoon)

77 = pen

88 = offshore spit/emergent reef

99 = island not present

SIZE Size is estimated using a classification scheme from Stone (1984), using the following terminology. Note 

that seals are "sized" by length, girth, appearance, and reproductive status, not by age (except pups):

Pup Seals born within the calendar year. Newborn pups are black, and weight ca. 11 to 15 kg. 

Pups molt to a silver-gray pelage near weaning. Weaning weight is ca. 50 to 80 kg.
B-6

Juvenile Short, slight seals from the length of a weaned pup (about 138 cm) to 20-30 cm longer; 

includes yearlings, and other young seals up to 3 years. Distinguished from pups by 

thinness and yellowish color.

Subadults Seals perceptibly longer than juveniles up to breeding size; less robust than adults, 

generally with lighter pelage. Immature seals ca. 3 to 5 or 6 years old.

Adult Reproductively active or breeding size seals at least as long as known breeders. Mature or 

probably mature seals. Adult females often have extensive back scars or wounds; adult 

males usually dark, including ventrum, and extensively scarred.

Code size as follows:

Pups of the year

P0 = Fetus/premature pup (<75cm dorsal straight length; pelage, whiskers, nails, or oral cavity not 

 fully developed).

 P = Nursing pup

P1 = Nursing pup, wrinkles. Full term (> 75cm DSL, fully developed pelage, 

whiskers, nails, and oral cavity).

P2 = Nursing pup, no wrinkles

P3 = Nursing pup, blimp, black

P4 = Nursing pup, molting

P5 = Nursing pup, molted

PW = Prematurely weaned/undersized weaned pup (weaned < 2 wks ago and < 90cm girth). 

Code as PW at time of weaning, and then can code as W for remainder of season.

 W = Weaned pup 

Immatures

I = Immature

J = Juvenile

J1 = Juvenile I

J2 = Juvenile II

 S = Subadult

S3 = Subadult III

S4 = Subadult IV

Adults

A = Adult

Unknowns

U = Seal of unknown size

Turtles

T = Turtle (lengths from anterior to posterior tip of carapace)

T1 = Turtle, juvenile (<65 cm straight carapace length)

T2 = Turtle, subadult (65 - 80 cm)

T3 = Turtle, adult (>80 cm)
B-7

Only code a seal’s sex as known if the ventral is seen, even if you "know" the sex because of the tag, bleach, 

scars, or behavior. The only exception is that the mother in a mother/pup pair should be recorded as a female. 

The sex of a turtle can only be distinguished externally if it is adult-sized.

SEX M = Male

F = Female

U = Unknown

 

BEACH POS. Location of seal or turtle when observer comes abreast of animal (e.g., if seal is seen in the water 

from a distance and yet is on the beach when the observer come abreast, the seal is recorded as 

being on the beach). When recording paired male-male contests (at Laysan and Lisianski Islands in 

2004), record contests as you see them ahead of you (within 30 m). When you come abreast of the 

seal, record the beach position and time and make this your original line. All previously recorded 

lines for this sighting will be reverse continuation lines.

0 = animal floating or swimming in water (not included in census tally but may be used for 

behavioral data or other analysis).

1 = on the beach (or regularly surveyed areas on the fringing reef for Midway Reef Surveys)

9 = on an offshore rock/reef with no connections to the island. Separated from shore by a 

deep channel or substantial distance, and not regularly surveyed (not included in census 

tally). For Midway Reef Surveys, use beach position 9 for the back side of the reef and 

other areas that are not regularly surveyed. For Laysan, use beach position 9 for the 

offshore rocks in sector 11/12.

X = data not taken

CONDITION Condition is recorded for all seals (except nursing pups) on census or atoll count. Always record

the condition of the mom on her first sighting postpartum, and of the mom and pup on their first 

sighting post-weaning, regardless of data type. Always note condition when recording a survival 

factor. Unusual conditions should be further described in Notes.

Condition codes:

M = medium 

P = probably pregnant 

F = fat

T = thin, includes emaciated (ribs visible, neck obvious, concave dorsal musculature)

X = data not taken

Codes F and T indicate extreme conditions, seals that are medium-fat, or medium-thin should be 

coded as medium. Always code condition explicitly.

Adult Females and

immatures of both sexes Adult males

Female

Male umbilicus

nipples

penile opening and groove
B-8

A seal is either identified or not during a sighting. If both the ID No. and Tag No. fields are empty, the seal is 

unidentified. If either the ID No./Tag No. field is filled, the seal may be identified depending on how the ? 

columns are filled. Questionable codes blank, 0, or 4 indicate the seal is identified with certainty, whereas codes 

1 or 5 indicate uncertainty. If a seal’s identity is confirmed by any method, coding for the entire sighting (on the 

original line and all continuation lines) must ultimately show certainty. For example, if the ID columns indicate 

the seal is identified with certainty but the Tag columns indicate uncertainty, look up the correct tag number 

during data editing, enter it, and change the Tag? code from uncertain (1 or 5) to certain (4)).

ID DATA These fields can be used to record either a temporary or permanent ID number. Although the paper 

form only has one ID field, the database actually has two ID fields. Thus, you can record both a 

temporary and a permanent ID number on a seal’s original line (to do this on the form, split the ID 

field horizontally and write both numbers on a single line, or expand the original line by sacrificing 

the subsequent line). Use continuation lines to record two or more temporary numbers. If the seal is 

identified, it will not be counted twice on census. To link two sightings of an unidentified seal 

during a survey (i.e. for a cruiser moving ahead of you), assign it a temporary number in a series 

reserved for unidentified seals, and code a 6 in the temp ? field.

T/P Indicate whether the number in the subsequent field is a temporary or permanent ID number.

T = temporary ID number (or bleach number)

P = permanent ID number

TEMPORARY ID NO. Record the temporary ID number (or bleach number) of seal if known; right justified. This 

field may be used for any temporary number. Use separate number series for bleach and 

various types of temporary numbers. If a number is incompletely read, use dashes as 

place-holders within the number to indicate missing digits (e.g., incompletely read bleach 

152 may be coded -52, 1-2, or 15-). 

? column: 

0 = seal is definitely unmarked; can coexist with a non-bleach temporary number, or with a 

bleach number if bleach hasn't taken yet or the number has molted off

1 = bleach is present but the recorded bleach number is questionable, and the seal is not 

 identifiable from other information

4 = partially read bleach number completed from other data

5 = incompletely read bleach number, there isn’t enough information to identify the seal but 

the partial data are certain, the seal is not identifiable from other information

6 = temporary number valid for this survey only (for unident. cruisers moving ahead of you on 

census, etc.). Use a special number series so these numbers are not confused with real 

temporary ID numbers. Numbers may be reused on the next survey for different seals.

blank = number is certain and complete if present

PERMANENT ID NO. Record the 4 digit permanent ID number of seal if known (put both the island-specific 

prefix and next digit in the first box provided).

? column: 

1 = ID number is questionable, and the seal is not identifiable from other information

blank= ID number is certain and complete if present. A Permanent ID is not visible, and is always 

completed from other data. For certain ID numbers, always use ID? = blank, not ID? =4.
B-9

TAG NO. The complete tag number if known; right justified. If a number is incompletely read, use dashes as 

place-holders within the number to indicate missing digits. Put the alpha prefix of the temple tag 

(combined with tag ? column code = 5) if you can determine the hole drilling pattern, but can't 

decipher the number (e.g. A--RT5 for a right tan tag with a 1983 drill pattern). Explain how you 

came up with the prefix, and draw the hole drill pattern in Notes.

Record all tag sightings explicitly (i.e., both left and right tag numbers) at least once during your 

stay. During the first weeks of the field camp, note tag condition each time that a tag is sighted. 

Once the majority of tags have been resighted, observers can carry a list of tags/individuals that 

haven't been seen, and only note tag condition if these tags/individuals are resighted. Also carry a 

list of broken or lost tags, and current tag conditions, so that you will be aware, and can record, if a 

specific tag breaks or is lost, or a tag condition changes during the field season. When a pup is 

tagged, record the animal handling event on the census data sheet, and record detailed information 

(such as all tag numbers, all temporary numbers, and the permanent number) on a 

Tagging/Handling card. If a seal is identified via a tag, it is not necessary to determine and enter its 

ID number on the census form. The ID number can be determined by computer later. 

L/R: Tag position 

L = tag on left flipper 

R = tag on right flipper

B = tags on both flippers (enter one tag number). This code can be used if the seal has only 2 

Temple tags (one on each flipper).

COL: Color code -see the Tag Sample Kit if unsure of the colors

Temple tags Other tag types

Y = yellow (FFS) M = metal, Monel 

T = tan/brown (Laysan) C = clear, PIT tag

G = green (Lisianski) 

B = blue (Pearl & Hermes)

P = pink (Midway, starting in 2004)

K = silver/gray (Kure) 

R = red (Necker, Nihoa, Main Islands, Midway prior to 2004)

? column:

0 = seal is definitely not tagged on either flipper. To indicate that a seal has lost a tag, code a 

known missing tag using tag? code 8. If the tag number is unknowable, write the 

information in Notes.

1 = seal is tagged but the recorded tag data are questionable, and the seal is not identifiable

from other information

4 = partially read tag completed from other data

5 = incompletely read tag, there isn’t enough information to identify the seal but the partial 

data are certain, the seal is not identifiable from other information

8 = a specific known tag is lost/unreadable. Fill out tag position (L/R) and the tag condition 

event with codes L or U. Complete the tag number and color from other data before entry.

blank = tag information is certain if present. Partial data (either complete Tag #, position, or color 

not filled) are OK and will be completed by computer if the seal is identified by ID, 

Temporary #, or Tag #, and there is only one possible tag for that flipper. The computer 

will only fill blank fields, so an incomplete Tag # must be completed by hand (use a "4" in 

the tag ? column).
B-10

MOLT Percentage of old pelage lost, optional for pups. However, for weaned pups, record the % molt at 

time of tagging. Record molt as 100% for at least 1 month post-molt. Code the full percentage (1 

to 100%) in the single box provided.

blank = no molting evident

1 to 99 = 1 to 99% molted. The first signs of molt usually occur around the eyes, nose, 

flippers, and scars. The first record of >10% of the old pelage molted off is 

considered the first day of true molt.

100 = 100% molted, freshly molted, required for the first month after molt. Put all 3 

digits of the 100 in the single box provided.

? column: 

0 = seal is definitely not molting

 1 = seal is molting, but % molt estimate is questionable. May or may not include an estimate 

in the molt column

"End of season" editing codes that override erroneous molt estimates:

2 = seal in molt

3 = seal pre-molt

4 = seal post-molt

DISTURB The degree to which the seal may have been disturbed by observer. Record disturbance every time 

a seal is disturbed, regardless of your activity. The only exception is that you do not need to record 

a disturbance for a seal that you are handling (i.e., tagging, disentangling).

0 = no disturbance, or seal merely raised its head or looked at observer - If column blank, 0 is 

assumed

1 = seal vocalized, gestured, or moved <2 body lengths

2 = seal alerted to observer and moved >2 body lengths

3 = seal alerted to observer and fled into water
B-11

ASSOCIATION DATA Behavior data is collected at Laysan and Lisianski Islands because adult male 

aggression has been more commonly observed at these locations, resulting in injury 

and death of adult female and immature seals. At Laysan, these data were used to 

identify 37 males for removal in a successful management action that reduced the 

adult sex ratio and increased female survival. Data are now used to monitor the long 

term effects of sex ratio adjustment at Laysan, and assess management options at 

Lisianski Island. 

Record spatial and pair associations involving adult and S4 seals at Laysan and 

Lisianski Islands in 2004. Don't record associations that only involve S3 or smaller 

sized seals or associations that involve turtles. If you wish to indicate that a seal was 

alone, use the O (this code is alpha, not zero!) behavior code. If you do not record 

association data on a census or behavior patrol at Laysan or Lisianski Island for any 

reason, indicate this with an X for the behavior code. Always explicitly record 

whether the seal is unassociated or association data is not recorded. Use 

continuation lines to record more than one association. 

An association should either be all blank or have the O, Z, or X behavior only (with no 

line number or distance), or have a line number, a distance, and some behavior code 

(other than O or X) all present. 

All associations should be recorded in pairs, i.e., between animals on two different 

lines. You should fill in the line numbers, distances, and behavior codes for both 

animals involved in each association. The association line number should refer 

directly to the line where the corresponding behavior is coded (i.e. if the corresponding 

code is on a continuation line, refer to that particular line, not to the original line or a 

different continuation line). If two seals are associated, the time recorded on their 

lines doesn’t need to match, but should be within 30 minutes of each other. 

Active associations will not be recorded in 2004. However, if a paired male-male contest occurs write a

brief summary in Notes and code the contest outcome (see the attached CONTEST RULES).

Spatial associations

1) noted as observer comes abreast of the subject. 

2) individual seals 

-mother-pup pair (N): any distance

-Adult or S4 seals (L): distances <10 m away, record two nearest neighbors in a straight 

line of sight. Seals can be on opposite sides of a log, etc. Only record the L 

associations of seals in their original configuration (don’t re-code if seals shift 

positions).

LINE NO. Identity of the other seal in the association. Put its line number here (note line number refers to 

within same census page only).

DIST. Closest distance during behavior - both associated lines must have the same minimum distance. 

0 = body contact

1 = <2 m

2 = 2-5 m

3 = >5 m (>5 m but <10 m in the case of L behavior code)
B-12

BEHAVIOR Up to four behaviors may be recorded for each association, but L, N, X, and O should not appear 

together with other behaviors. If there is a paired male-male contest write a brief summary in 

Notes. Focus on the major points, such as the seals involved, pairings before and after the 

interaction, the contest winner/loser, and the most intense behaviors (joust, bite, mount, chase, 

displace). 

1) individual seal 

a) spatial association

N =mother-pup pair (any distance), does not imply actual nursing behavior. This is the 

only association recorded between mother-pup pairs, and the N code must be on the 

original line for each pair member. If there is an unusual event (i.e., birth, weaning, or 

pup switch) write a brief summary in Notes and use the appropriate Notes Code. 

L = association by location only (distance <10 m apart, for all except mother-pup pairs). 

Z = cruising (OPTIONAL CODE). A/S4 only behavior (actual sex may be unknown). 

Does not require a line number reference to another seal, but may have one.

b) additional codes (Laysan and Lisianski 2004)

*L1 =pair assoc. A/S4 male actively defends an adult female or immature of either sex 

(actual sex may be unknown), or establishes a pair relationship with a female or 

immature after displacing another male. Code the L1 relationship both before and 

after the contest if a displacement occurs.

*Q = loser (quitter) 

*W = winner

*Y = tie 

Note: codes Q, W, and Y are used for A/S4 male-male contests only, although the actual

sexes may be unknown (in which case record as though they were known to be 

males); see the attached CONTEST RULES. 

* requires a corresponding code on the line of the associated seal

Code Corresponding code

N.....................N

L.....................L

L1....................L1

 Q.....................W

W.....................Q

Y.....................Y

2) nothing nearby

O = no behavior or association

3) no data

X = no association data recorded on Census or Atoll Count
B-13

NOTES--There is room to code 2 different notes. Always use the first column first. Code an H if you have 

handwritten notes on the observation. Put handwritten notes on the bottom of the census form, labeled by line 

number. If more than two note codes apply, use continuation lines. 

A = artwork (scars drawn) - attach drawing, labeled with date, island, observer, data type, page number, 

and line number 

B = birth, 1st sighting postpartum (mom and pup)

G = seal is green with algae

H = handwritten notes

M = marked, indicate each time a seal is bleached (includes attempts to bleach)

W = weaning, 1st sighting post-weaning (pup or mom, whichever sighting confirms weaning or end of 

nursing (i.e., mom alone after pup disappearance).

X = pup exchange, 1st sighting after exchange (mom and pup)

Y = disturbance is to "bystander" seal during non-survey activity such as tagging, bleaching, 

instrumenting, disentangling, etc. This includes all animal handlings/"hands on" research, even if 

the attempt was unsuccessful (i.e., removing dead pups, cutting umbilical cords, or reuniting pups 

with their mothers).

FOR DATA TYPE "T" (TO RECORD THAT A GIVEN TAG IS NOW INACTIVE/NOT ON A SEAL):

F = tag found 

R = tag recovered from seal in hand 

EVENTThese columns are used to record a variety of data. The codes used will depend upon the type of event that 

you wish to record. Left justify your coding:

TYPE CODES CONTENT

COLUMN

F = survival factor ONLY RECORD RESIGHT OF A SURVIVAL FACTOR AS AN EVENT IF 

THERE ARE IMPORTANT CHANGES TO DOCUMENT, SUCH AS A NEW 

WOUND, HEALING, DEATH, ETC., TRANSCRIBE NOTES TO SURVIVAL 

FACTOR FORM. For turtles, use a different survival factor number series (i.e., 

begin at 500), fill out a survival factor form (or use an alternate format if specified 

by mtrp), but do not enter the data into the seal survival factor database.

1-3 Survival Factor number 

 4 Factor Type. If seal dead, always record factor type "D" on 

ORIGINAL LINE. For mobbings/ harassments, always code 

a census entry with factor type "M" for the victim at the 

beginning and end of the incident. Otherwise, you only need 

to record the most appropriate factor type if more than one 

applies. 

D = death

W = wound (includes abscess/raised area)

E = entanglement

V = very thin (emaciated)

I = illness/abnormal (includes eye disease)

M = mobbing/harassment/post-mobbing 

aggregation

O = other

 5 Participant type (for mobbings/ harassments/post-mobbing 

aggreg. only)

 V = victim/subject

 M = male aggressor
B-14

H = handling of wild seal HANDLINGS DO NOT NECESSARILY INVOLVE RESTRAINT OF THE SEAL. 

FILL OUT BOTH A SEAL SIGHTING (WITH HANDLING EVENT) AND A 

TAGGING/HANDLING CARD. For direct translocations, fill out two seal sightings with 

handling events (one each at the time of capture C and at the time of release F) and fill out 

a single tag/handling card with restraint time from capture until release into the wild. In 

cases where the translocated seal is held in a pen before release into the wild, fill out four 

seal sightings with handling events (one each at the time of initial capture C, “release” into 

pen O, “capture” in pen O, and release into wild F) and fill out two tag/handling cards, one 

at the time of initial capture (with restraint time until “release” into the pen) and a second 

card at the time of “capture” in the pen (with restraint time until release into the wild).

 1 Handling type

T = tagging (w/ restraint)

M = measuring (includes weighing)

A = all (both tagging and measuring)

R = remote tagging

D = disentangle (even if not restrained)

I = instrument application

B = bleeding

C = take from the wild into captivity (or capture for 

translocation) 

F = free from captivity (or free after translocation) 

into the wild

O = other (includes instrument removal and 

“captures/releases” of seals within a pen) 

TYPE CODES CONTENT

COLUMN

P = photo SEAL OR TURTLE PHOTOS ARE THE ONLY PHOTOS CODED ON THE 

CENSUS FORM. OTHER PHOTOS SHOULD BE RECORDED IN NOTES, 

AND TRANSFERRED TO THE PHOTO COMMENT FORM. 

 1 Type of photo

S = slide

P = print

D = digital

2-5 Digital: Consecutive File Number, or

Film: columns 2-3 Roll number (pad with zeros) 

columns 4-5 Frame number (pad with zeros)

 6 Side

L = left lateral or flipper

R = right lateral or flipper

D = dorsal side

V = ventral side

 B = both (used for rear flippers only)

X = other, describe in hand-written NOTES
B-15

D

C B

A A

B C

D

 7 Part

 H = head

 A = anterior body (neck and shoulders)

 M = midbody (behind fore-flippers and before posterior)

 P = posterior body (behind midbody and before rear 

 flippers)

 F = foreflipper; write whether dorsal/ventral in 

 comments

 R = rearflipper; write whether dorsal/ventral in 

 comments

 O = overall view of a particular side

 \X = other, describe in comments

8 Purpose

I = identification

F = survival factor (link with survival factor EVENT 

using continuation lines)

X = other, describe in comments

TYPE CODES CONTENT

COLUMN

T = tag condition RECORD TAG CONDITION FOR BOTH SIDES OF EACH TAG AT LEAST 

ONCE DURING THE SEASON. If tag condition is recorded for an incompletely 

read tag, complete the tag number (with appropriate tag? Code) prior to computer 

entry.

1 Web 

 A-D = from inner (medial) to outer web.

 E = ankle

 P = posterior

U = unknown

2 Side of tag, the dorsal tag side is on the dorsal flipper surface 

unless the tag is reversed. For Temple Tags, the dorsal side 

is the bigger side; for Metal (Monel) tags, the dorsal side is 

the "male" side. For PIT tags, code the side as B (both). 

D = dorsal

 V = ventral 

B = both 

U = unknown

 
B-16

 3 Condition, code U (unreadable) if cannot use tag to ID seal (i.e. if 

 broken so number gone). Also code U for a PIT tag if you 

 completely scan for it with a reliable reader but get no reading. If 

 reader is unreliable, put attempt in Notes and only code PIT tag as 

 unreadable after 3 separate attempts. Combine the L or U codes 

 with the tag questionable code of 8. You can combine the tag 

 questionable code of 8 with other condition codes to describe why 

 the tag is unreadable (i.e., worn or broken). Unreadable tags can 

 still be used as partial information to help determine a seal’s 

 identity. Code more than one condition using continuation lines.

B = broken

F = faded color

G = good

L = tag lost 

N = no/partial resin

O = other 

P = pulling out

U = unreadable

V = tag side reversed 

W = no. worn /abraded 
B-17

CONTEST RULES

1. Male-male contest definition (must conform to at least one condition below):

a. Distance between adult males = 0

b. Either adult male vocalizes, chases, displaces or jousts with the other male

2. The contest outcome depends upon pair type (what size/sex seal the adult male is paired with) 

a. For contest rules, size S4 seals are considered to be adults (both sexes), seals size S3 or smaller are 

considered to be immature 

b. Definition of (L1) pair type:

i. Pair type #1: adult male paired with (actively defending) an adult female

ii. Pair type #2: adult male paired with (actively defending) an immature seal of either sex 

3. Contest outcomes (definition of winner or loser adult male):

Case Winner (W) Loser (Q) Tie (Y)

Paired Male vs. 

Single Male:

i) The paired male wins if he is not 

displaced

ii) The single male wins if he 

displaces the original paired male

Unsuccessful single 

male 

Displaced originally 

paired male 

No Ties

No Ties

Male Paired with 

Adult Female vs. 

Male Paired with 

Immature Seal:

 (#1 vs. #2)

i) The male paired with the adult 

female wins if he is not displaced 

ii) The male paired with the immature 

seal if he displaces the male 

originally paired with the adult 

female

Unsuccessful male 

paired with immature

Displaced originally 

paired male

No Ties

No Ties

Paired Male vs. 

Paired Male of 

equal pair type:

(#1 vs. #1 or

#2 vs. #2)

Displaces the other seal Is displaced Tie if neither seal 

is displaced

1.Generalizations:

a. Unequal pair types

i. There are no ties 

ii. The male with the higher pair type (1>2) always wins unless he is displaced

iii. A seal can win without being aware of the contest. For example, if the "winner" is not aware 

that the other seal flees, but that seal fled in response to a vocalization, then code the fleeing 

seal as the loser (Q) and the other seal as the winner (W))

b. Equal pair types

i. Males tie unless there is a clear winner/loser

 ii. To win, a male must displace the other male 
B-18

HAWAIIAN MONK SEAL TEMPLE TAGS:

NUMBERING SCHEME AND HOLE DRILLING PATTERN FOR TAGS APPLIED TO WEANED PUPS

R 2 5

1996 .P05

G 7 7

Z 01

S 1 4

X12

J 05

C11

1990

1991

1992

1993

1994

1995 .

.

.

.

.

.

. .

.

1997 Q 17 .

O50

A 23

T 35

K18

L69

N36

F 05

U 1 9

1982

1983

1984

1985

1986

1987

1988

1989

screw

.

.

.

..

..

.

.

.

.

.

.

hole

. 1998 Y33.

1999 D 15 . .

.

2000 H1 0.

2001 M 24 . .

2002 . E 1 2.

2003

.

.

2004 I 4 0

.

Extra hole

MDY 

R00-R39

Be sure to code the original tag color, not the color that a tag has faded to. See the Tag Sample Kit.

Original tag color: Faded tag may appear:

Temple Tags:

Yellow...................................................White, Lt. Yellow

Light Tan (A,T,K,L series @ Laysan).............Gray, Lt. Yellow, White

Dark Tan/Brown (later series @ Laysan)..........Red

Dark Forest Green.....................................Dark Blue, Navy

Kelly Green (C, P, and Y cohorts)................. --

Blue (light)...............................................--

Red.......................................................Orange

Gray (A,T,K,L,N,F,U,G series @ Kure).........Light Tan

Silver Gray (600-900,0,Z and later @ Kure)......Metal
Availability of NOAA Technical Memorandum NMFS

Copies of this and other documents in the NOAA Technical Memorandum NMFS series issued 

by the Pacific Islands Fisheries Science Center are available online at the PIFSC Web site 

http://www.pifsc.noaa.gov in PDF format. 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, Springfield, VA 22161, U.S.A. [Tel: (703)-605-6000]; URL: 

http://www.ntis.gov. A fee may be charged.

Recent issues of NOAA Technical Memorandum NMFS–PIFSC are listed below:

NOAA-TM-NMFS-PIFSC-20 Demand for Hawaii bottomfish revisited: incorporating

economics into total allowable catch management.

J. HOSPITAL, and M. PAN

(September 2009)

 21 Shark predation on Hawaiian monk seals: Workshop II &

post-workshop developments, November 5−6, 2008.

K. S. GOBUSH

(July 2010)

 22 Status review of Hawaiian insular false killer whales

(Pseudorca crassidens) under the Endangered Species Act.

E. M. OLESON, C. H. BOGGS, K. A. FORNEY, M. B. 

HANSON, D. R. KOBAYASHI, B. L. TAYLOR, P. R. WADE, 

and G. M. YLITALO

(August 2010)

 

23 Hawaiian monk seals and their prey: assessing characteristics

of prey species fatty acid signatures and consequences for

estimating monk seal diets using quantitative fatty acid signature

analysis.

S. IVERSON, J. PICHÉ, and W. BLANCHARD

(March 2011)

 

24 Historic fishing methods in American Samoa.

K. ARMSTRONG, D. HERDRICK, and A. LEVINE

(June 2011)

25 Aversive conditioning and monk seal-human interactions in the

main Hawaiian Islands: Aversive conditioning workshop, 

Honolulu, Hawaii, November 10-11, 2009.

E. M. JENKINSON

(July 2011)