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, 

NOAA Technical Memorandum NMFS 

MARCH 1986 

HAWAIIAN MONK SEAL OBSERVATIONS 

AND CAPTIVE MAINTENANCE PROJECT 

AT KURE ATOLL, 1981 

William G. Gilmartin 

Robert J. Morrow 

Anne M. Houtman 

NOAA-TM-NMFS-S WFC-59 

U.S. DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Southwest Fisheries Center 
NOAA Technical Memorandum NMFS 

The National Oceanic and Atmospheric Administration (NOAA), organized in 

1970, has evolved into an agency which establishes national policies and 

manages and conserves our oceanic, coastal, and atmospheric resources. An 

organizational element within NOAA, the Office of Fisheries is responsible for 

fisheries policy and the direction of the National Marine Fisheries Service 

(NMFS). 

In addition to its formal publications, the NMFS uses the NOAA Technical 

Memorandum series to issue informal scientific and technical publications when 

complete formal review and editorial processing are not appropriate or feasible. 

Oocuments within this series, however, reflect sound professional work and may 

be referenced in the formal scientific and technical literature. 
NOAA Technical Memorandum NMFS 

The TM series e used for docurnenullon and timely communtcabon of prslrmmmy results. tmlorim repom. of 

vial purpoS0 informahon. and have not received ccnnplets lormal review. sdiuml control. or dauled edihng 

MARCH 1986 

HAWAIIAN MONK SEAL OBSERVATIONS 

AND CAPTIVE MAINTENANCE PROJECT 

AT KURE ATOLL, 1981 

William G. Gilmartin 

Robert J. Morrow 

Anne M. Houtman 

Southwest Fisheries Center Honolulu Laboratory 

National Marine Fisheries Service, NOAA 

Honolulu, Hawaii 968 12 

NOAA-TM-NMFS-SWFC-59 

U.S. DEPARTMENT OF COMMERCE 

Malcolm Baldrige, Secretary 

National Oceanic and Atmospheric Administration 

Anthony J. Calio. Administrator 

National Marine Fisheries Service 

William G. Gordon. Assistant Administrator for Fisheries 
The mean beach count of Hawaiian monk seals at Kure Atoll 1 April13 September 1981 was 20.8, excluding pups of the year. Six female and 

four male pups were born between mid-February and late August. 

pups were born on Green Island, four on Sand Island. A single female pup 

disappeared before weaning and a male pup disappeared about 1 month after 

weaning. 

Six of the 

The other eight pups were double flipper tagged gfter weaning. 

Five female pups were captured after weaning and maintained for a 

limited time in a large beach enclosure. 

locally caught reef fishes and invertebrates. 

2 September and one disappeared within a few days. 

seals have been resighted at Kure Atoll each field season through 1985. 

These seals were fed live 

The pups were released on 

The four other female 
Kure Atoll, located at the western end of the Hawaiian Archipelago, 

supports a population of the Hawaiian monk seal, Monachus schauinslandi, 

which has been declining during the past 25 years (Johnson et al. 1982). 

The natural history of Kure Atoll, including early human impacts on monk 

seals and some beach count information, is reviewed in Woodward (1972). 

Mortality and disappearance of monk sed pups at Kure Atoll were first 

reported by Wirtz (1968). 

12 died, and 49 of the remaining 50 disappeared between 16 and 74 days of 

age. Some of those found dead were believed killed by sharks which are 

nearshore in the late spring and summer, probably attracted by fledging 

seabirds in the water. 

lacerations and badly bruised tissue which Wirtz believed may have been 

inflicted by adult male monk seals. 

confirmed the source of this type of injury to be adult males (Johnson and 

Johnson 1981; Alcorn 1984; Johanos and Kam 1986). 

He found that of 62 pups born in 1964 and 1965, 

Other pups had open back wounds surrounded by 

Subsequent observations by others have 

Births at Kure substantially declined from 30-32 pups per year in 1965 

and 1964, respectively, to 9-13 pups per year from 1977 through 1980 

(Johnson et al. 1982; Kenyonl’ 2; Ruehle and Johnson3). 

also remained low based on summer census data from 1976 through 1980 which 

gave the following high beach counts of juveniles and subadults: 1976: 0, 

1977: 3. 1978: 3, 1979: 4, and 1980: 5 (Johnson et al. 1982; see footnotes 

1, 2,). 

that recruitment of breeding seals was so low that survival of the Kure 

population was in jeopardy (Gilmartin et al. 4). 

Pup survival has 

The decreasing number of births and the low survival caused concern 

In addition to the two probable traumatic causes of pup death 

mentioned above, other potential causes included disease, natural toxins in 

the reef fishes, and congenital problems. 

In an attempt to enhance survival of monk seal pups at Kure Atoll, an 

experimental temporary captive maintenance project was conducted in 1981. -- Results of this project are presented here together with other 

and reproductive data collected in 1981. 

population 

IKenyon, K. W. 1979. Hawaiian monk seal obsemations at 

2Kenyon. K. W. 1980. Hawaiian monk seal observations at 

10-22 May 1979. 55 p. 

17 June-3 July 1980. 

Wildl, Serv., 35 p. + figs. 

other wildlife of Kure Atoll, 10 February-13 

40 p. 

kGilmartin, W. G. 1984. Recovery plan 

Monachus schauinslandi, 44 p. 

Unpubl. manuscr. Natl. 

SRuehle, J., and A. M. Johnson. 1977. 

Fish Wildl. Lab. , 

Kure Atoll 

U.S. Fish 

Observations of monk seals and 

May 1977. Manuscr. in prep., 

for the Hawaiian monk seal, 
2 

METHODS 

Observations and censuses of monk seals on Green Island and the 

adjacent sand islets (Sand Island and Shark Island) at Kure Atoll (Fig. 1) 

were conducted almost daily from 1 April to 13 September, and then 

irregularly at 1-2 week intervals through the remainder of 1981. 

(1984) describes which seals were included in a beach count and the size 

class criteria into which most were assigned. 

Stone 

All but one pup of the year were tagged on both hind flippers with 

gray Temple Tags5 while being physically restrained by one person. A 5-mm 

diameter hole was punched through the webbing between the fourth and fifth 

digits using a leather punch tool. The single piece plastic tag was then 

inserted through this hole to the position where the connecting post of the 

two plates was in the punched hole. 

marked with large symbols on their pelage using a canmercial hair 

lightener. 

of tagging and weights were obtained by suspending the pup in a hoop net 

from a spring scale. All of the above activities were performed on the 

pups following weaning. 

The pups, while sleeping, were also 

Standard length and girth measurements were taken at the time 

Construction of a 36 x 61 m enclosure consisting of welded wire mesh 

supported by galvanized pipe posts was completed on 5 June. 

was located on the southwest beach of Green Island (Fig. 1) and enclosed 

equal areas of sand and water; the fence height was about 0.8 m on the 

beach and 0.5 m above high tide in the water. The maximum water depth at 

low tide was approximately 1.5 m. Three female pups which had been weaned 

earlier in the season were captured and placed into the enclosure as soon 

as it was completed. 

also placed in the pen. 

by hand to the pen or transported by small boat. 

placement in the enclosure did not exceed 20 min. 

The enclosure 

Two other female pups were collected subsequently and 

The pups were captured with a hoop net and carried 

Time from capture to 

The pups in the enclosure were fed fish and invertebrates which were 

trapped or netted in the lagoon near Green Island. 

(1 x 1 x 0.5 m) were placed near coral heads within 500 m of the enclosure 

and fish caught in the traps were collected daily. 

some gill netting adjacent to the enclosure at least every other day, 

provided ample fish to feed the five pups. 

yielded from 2 to 20 kg of fish per day. 

the most abundant fish in the traps. 

Mulloidichthys spp.; manini, Acanthurus triostegus; various wrasses, 

Labridae: and butterfly fishes, Chaetodon spp., were also common. 

Occasionally, lobsters, Panulirus spp., and conger and moray eels were also 

recovered in the traps and they too were offered to the pups. 

catch each day was released into the enclosure alive, except during same of 

the initial feeding sessions when dead or stunned fish were presented. 

Four fish traps 

This, together with 

The trapping and netting 

Nenue, Kyphosus cinerascens, were 

Squirrelfish. Adioryx spp.; weke, 

The total 

5Reference to trade names does not imply endorsement by the National 

Marine Fisheries Service. NOM. 
3 

0 .I .2 .3 .4 .5 km 

Figure 1.--Kure Atoll. and Green Island, showing the monk seal 

enclosure site, off limits area, and 1981 pupping sites. 
The five pups in the enclosure were released on 2 September. The 

fencing was simply removed from the enclosure: no attempt was made to 

actively release the pups by chasing them from the pen. 

resightings of the pups through the winter were recorded by U.S. Coast 

Guard personnel and in subsequent years by National Marine Fisheries 

Service (NMFS) staff. 

Following release. 

v 

RESULTS AND DISCIISSION 

All of the atoll-wide monk seal census data are presented in Table 1. 

The mean count for all seals except pups of the year was 20.8. Kenyon (see 

footnotes 1. 2) reported mean counts of all seals on Green Island and the 

Sand Islets as 24.5 in 1979 and 17.9 in 1980. The mean count of 26 for all 

seals in 1981 is not comparable to the earlier counts of Kenyon because it 

includes all pups in the enclosure and includes counts later in the summer 

when adult males are molting. 

size and sex class in a single census and the dates in parentheses were: 

adult males: 18 (9/5); adult females: 6 (6/17, 8/21; subadult males: 3 

(9/5); subadult females: 1 (4/3, 4/16. 6/17, 6/25. 8/6, 9/5. 9/13); 

jwenile males: 4 (6/25): and juvenile females 2 (6/21, 8/20). In spite of 

known differences in hauling patterns by sex and season (Stone 1984). these 

census data indicate that males outnumbered females a Kure Atoll, an 

the hauling locations of all non-nursing adult females sighted on Green 

Island during 1981 censuses. There is a clear preference for Northwest 

Beach and, to a lesser extent, North Point. an area designated as "off 

limits" to Coast Guard personnel stationed on the island. 

The highest atoll-wide beach counts for each 

observation confirmed in more recent work (Gerrodette 6 ). Figure 2 shows 

A summary of information on the 1981 pups is presented in Table 2. 

Six of the 10 pups were born on Green Island which was historically the 

major pupping island at the atoll. In the recent past, however. it had 

lost its appeal as a birth site. probably because of constant human 

associated disturbance with beach vehicles and dogs (Kenyon 1972). The 

return of pupping to Green Island is probably a result of decreasing beach 

disturbance which should contribute to better pup survival. 

occurred in all months from February through August. with the exception of 

July. 

births on Green Island are shown in Figure 1. 

In 1981 births 

The mean nursing time was approximately 40 days. Sites of the six 

The capture and release weights of the female pups are shown in Table 3. 

The mean weight loss for the five was 23% of their capture weight. 

seal pups will normally lose up to 50% of their weaning weight during the 

6-12 months following weaning. 

appeared less than that of seal pups in the wild during the same time 

period based on subjective visual size comparison. 

Monk 

"he decrease in the size of captive pups 

6Gerrodette, T. 1985. Estimating the 1983 population of Hawaiian 

monk seals from beach counts. Southwest Fish. Cent. Honolulu Lab., Natl. 

Mar. Fish. Sen., NOM. Admin. Rep. H-85-5. 13 p. 
5 - 

Table 1.--Summary of Hawaiian monk seal beach counts for Kure Atoll, 1981. 

~~ 

Non-pups 

4/ 1 

4/ 3 

4/16 

5/21 

6/17 

6/21 

6/25 

7/11 

7/17 

7/21 

7/25 

7/29 

8/ 2 

8/ 6 

8/20 

8/24 

8/28 

9/ 1 

9/5 

9/13 

8/16 

9 3 0 10 0 2 1 0 1 0 0 0 0 3 217 4 21 

5 2 4 0 0 0 10 11 0 0 0 0 1219 2 21 

13 3 4 11 11 0 0 10 0 0 0 3 225 4 29 

644111001100121 185 23 

865111000030020 225 27 

533 IO 11 20030020 2185 23 

1031010400030010 194 23 

422000001030020 95 14 

931200212050000 205 25 

7 4 2 2 0 0 3 10 0 5 0 0 0 0 221 5 26 

766100210050000 235 28 

923 013100150000 196 25 

703203101050000 175 22 

83 8201 2200501 00227 6 33 

13 5 2 0 0 11 12 15 0 10 0 226 7 33 

726202000150100 197 26 

15 18 10 12 0 10 5 0 0 0 0 230 5 35 

1814311310020100 323 35 

1528112210120100 324 36 

5211003100500002145 19 

5300003010500002175 22 

'Weaned female pups in the protective enclosure were included in the census. 

2Total includes some seals which were not placed in any size/sex class. 

censuses were not used to calculate the mean non-pup beach count reported in the 

test. 

These 
6 

NORTH 

*** 

Figure 2.--Map showing the locations (0) of all non-nursing 

adult female monk seal sightings during the 1981 field season 

on Green Island. 
7 

Table 2.--Pups born on Kure Atoll, 1981. 

Birth Time Tag (gray) 

Weaning nursing Tagging ----------- Capture -------------- PUP 

No. Sex Place Date date (days) date Left Right date2 

- 

5 

26 

53 

56 

50 

64 

00 

82 

83 

131 

M 

M 

M 

F 

F 

F 

F 

F 

F 

M 

G 2/18 3/23 33 6/17 615 616 -- 

G 3/10 4/22 43 6/08 609 610 I 

S -3 wk 4/25-26 -35 (not seen after 5/21/81) 

old, 4/11 

S -10 d Not -- 6/11 606 612 6/09 

old, 4/11 determined 

G 4/10 6/01 52 6/11 605 604 6/06 

G 4/19 5/20 31 6/11 607 608 6/06 

G Between Disappeared with mother 2-3 June 

5/5 and 5/19 

S - 6/03 7/17 - 44 7/18 617 618 7/18 

S - 6/06 7 /17 - 41 7/18 890 900 7/18 

G 8/17 9/25 39 10/7 621 620 -- 

'G = Green Island and S = Sand Island. 

2KL1 pups were released on 2 September 1985. 

Table 3.--Kure Atoll captive pup weights, 1981. 

PUP Capture weight Time in enclosure Release weight Percent 

No. (kg) (days) (kg) loss 

56 

50 

64 

82 

83 

56.8 

87.7 

75.0 

80.9 

84.1 

85 

88 

88 

46 

46 

44.5 

65.9 

55.0 

64.1 

69.1 

22 

24 

26 

21 

18 
The pups were observed to consume at least some of all species of fish 

offered to them as well as lobsters. one eel. and one hermit crab. There 

was a clear preference for the butterfly fishes and weke. Based on 24 h 

observations the seals appeared to chase fish more at night than during 

daylight hours. 

and were occasionally seen mouthing sea cucumbers. Once they began 

mouthing fish, they all progressed quickly to catching livg fish. 

observed that the last two pups placed in the pen began eating much sooner 

than the original three animals: presumably seeing the older pups catching 

and consuming fish enabled them to learn the techniques faster. No health 

problems were encountered by pups during the 3 months of maintenance and. 

once a pup began eating. it was observed eating regularly. 

Initially. the pups would take only dead or stunned fish 

It was 

Following release of the seals on 2 September 1981. only one animal 

(pup No. 64) has never been resighted and is presumably dead. 

seen the day of release. The other four females have been 'resighted 

regularly in subsequent years through the summer of 1985. 

She was last 

The female pups appeared healthy throughout their captive maintenance 

At 

period and neither the quantity nor quality of fish which was made 

available to the pups appeared to negatively impact their developnent. 

least in 1981. toxins in reef fishes were not a problem. 

speculation that congenital problems may have been a cause of high 

mortality of Kure pups does not seem valid. This work demonstrated that 

protecting female monk seal pups at Kure Atoll from being traumatized by 

adult male seals or attacked by sharks during their first summer can 

greatly enhance their probability of survival. 

Similarly. 

The original concept for this project came from Ancel Johnson. USEWS. 

Anchorage. Alaska. He also suggested the use of the Temple Tag on monk 

seals, which now appear to have a very high retention rate. 

assistance with the field observations and pup care was provided by Karl 

Kellar. Bonnie Storm. Amy Uyemura. and Deanna Vick. Personnel of the U.S. 

Coast Guard. Kure Island Loran Station. pravided various types of support 

assistance on a day-to-day basis and the Coast Guard Air Station. Barbers 

Point, Oahu. provided transportation to Kure Atoll. 

Important 

LITERA'HIREJ. CITED 

ALCORN. D. 

1984. The Hawaiian monk seal on Laysan Island 1982. U.S. Dep. Commer., 

NOM Tech. Memo. NMFS. NOAA-TM-NME'S-SWFC-42. 37 p. 

JOHANOS, T. C.. and A. K. H. KAM. 

1986. The Hawaiian monk seal on Lisianski Island: 1983. U.S. Dep. 

Cmmer.. NOM Tech. Memo. NMFS. NOAA-TM-NMFS-SWFC-58. 37 p. 
JOHNSON. A. M., R. L. DELONG, C. H. FISCUS, and K. W. KENYON. 

1982. Population status of the Hawaiian monk seal, (Monachus 

schauinslandi) , 1978. J. Mammal. 63 :415-421. 

JOHNSON. B. W.. and P. A. JOHNSON. 

1981. The Hawaiian monk seal on Laysan, 1978. Final report submitted 

to U.S. Marine Mammal Commission, Wash., D.C. Contract MM8AC 008. 

Available U.S. Dep. Commer., Natl. Tech. Inf. Serv.. Springfield, VA 

22161, as PB-82-109661, 17 p. 

KENYON, K. W. 

1972. Man versus the monk seal. J. Mammal. 53:687-696. 

STONE. H. S. 

1984. Hawaiian monk seal population research. Lisianski Island, 1982. 

U.S. Dep. Comer.. NOM Tech. Memo. NMFS. NOAA-TM-NMFS-SWFC-47, 33 p. 

WIRTZ. W. 0.. 11. 

1968. Reproduction. growth and development, and.jwenile mortality in 

the Hawaiian monk seal. J. Mammal. 49:229-238. 

WOODWARD. P. W. 

1972. The natural history of Kure Atoll, Northwestern Hawaiian 

Islands. Atoll Res. Bull. 164:l-318. 
RECENT TECHNICAL MEMORANDUMS 

Copies of this and other NOAA Technical Memorandums are available from the National Technical 

Information Service, 5285 Port Royal Road, Springfield, VA 22167. Paper copies vary in price. 

Microfiche copies cost $4.50. Recent issues of NOAA Technical Memorandums from the NMFS 

Southwest Fisheries Center are listed below: 

NOAA TM-NMFS SWFC 49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

Observations of the Hawaiian Monk Seal on Laysan Island from 

1 977 through 1980. 

B.W. JOHNSON and P.A. JOHNSON 

(October 1984) 

Hawaiian Monk Seal observations on French Frigate Shoals, 1980. 

P.A. JOHNSON and B.W. JOHNSON 

(October 1984) 

Estimating dolphin juvenile survival rates from the proportion of 

calves nursing. 

T. POLACHECK 

(October 1984) 

Operational plan for NMFS albacore program. 

R.H. PARRISH, et al. 

(May 1985) 

Albacore fishing and windspeed. 

P.N. SUND 

(June 1985) 

Proceedings of the workshop on the fate and impact of marine 

debris, 27-29, November 1985, Honolulu, Hawaii. 

R.S. SHOMURA and H.O. YOSHIDA (Editors) 

(August 1985) 

The Hawaiian Monk Seal and Green Turtle on Necker Island, 1983. 

R.J. MORROW and E.K. BUELNA 

(November 1985) 

Proportions of species of dolphin in the eastern tropical Pacific. 

J. BARLOW and R.S. HOLT 

(January 1986) 

A budget simulation model for west coast albacore trollers. 

S.F. HERRICK and K.L. CARLSON 

(February 1986) 

The Hawaiian Monk Seal on Lisianski Island: 1983. 

T.C. JOHANOS and A.K.H. KAM 

(February 1 986)