Remigration and residency of Hawaiian green turtles in coastal waters of Honokowai, West Maui, Hawaii
Peter Bennett1 (honu@turtles.org), Ursula Keuper-Bennett1 (howzit@turtles.org) and George H. Balazs2 (gbalazs@honlab.nmfs.hawaii.edu)

1Turtle Trax, 24 Reid Dr, Unit 3, Mississauga, Ontario, Canada L5M 3A6
2National Marine Fisheries Service, Southwest Fisheries Science Center, Honolulu Laboratory, Honolulu, 2570 Dole Street, Honolulu, Hawaii 96822, USA


Profiles of fives tagged fermales resident at Honokowai

During the period 1989-1999, five adult females (Tutu U521, McTaggert F765, Mendelbrot U359, Tiamat 122C, and Shredder A240) have made nesting migrations to the French Frigate Shoals (FFS) and returned to Honokowai. Three of these females (Tutu U521, McTaggert F765, and Mendelbrot U359) have made two or more migrations during this period. This involves a round-trip swimming voyage of at least 2 000 km. Tutu (U521), first identified by photograph in 1990, completed her fourth documented migration during this time.

Three of the five females (McTaggert F765, Mendelbrot U359 and Tiamat 122C) were sub-adults (65-85 cm carapace length) when first sighted, and subsequently matured at Honokowai. They migrated to FFS where they were issued their first set of flipper tags. Observations at Honokowai, captured on photographs and videotape, provided a historical record of these turtles before they were tagged, an unusual circumstance. The combined National Marine Fisheries Service (NMFS) and Honokowai records are shown in Tables 1-5.

The reproductive behaviour of the three honu suggests that young females on their first migration return to the place where they spent their late developmental years. For example, we recorded Tiamat for six consecutive years at Honokowai before she made her first documented FFS nesting migration in 1997--when she was issued tag 122C. In 1998 and again in 1999 she was regularly present at Honokowai.

Two turtles already had tags when first sighted. If these two turtles are like the three younger females, it is highly probable that Tutu (U521) and Shredder (A240) lived at Honokowai when they migrated/nested for the first time. Considering the powerful site fidelity of female honu to their resting/foraging grounds, it is possible that all five of these females have spent all their post-pelagic years in this small area of West Maui (approximately 25 hectares). As a result, there exists the romantic possibility that some honu spend their entire lives within the same reef system.

Implications of fixity in honu

This fixity makes honu vulnerable to persistent pollution sources and other anthropogenic assaults. It therefore follows that it is imperative that humans do all they can to keep sea turtle habitat--and the ocean in general--clean.

Of the five females, three have had fibropapilloma (FP) tumors and regressed. In 1999, we documented tumors for the first time in a fourth, Shredder (A240).

Honu fixity and tameness offers unique opportunities for researchers to study the etiology of FP in free-ranging turtles living in the same habitat over many years. With such impressive long-term residency, no other sea turtles in the world have offered such a "window" into their private lives--a window that might well remain open for decades!

Example of fixity for a Honokowai female

Fetches a 51K JPEG
Mendelbrot U359 nesting at the French Frigate Shoals, June 1998

51K JPEG

In June 1998, Mendelbrot was sighted on East Island laying her eggs. She is U359 and the good people monitoring turtles there took a picture of her. This makes Mendelbrot the first Honokowai turtle for which we have a photographic history in both nesting and foraging habitat.

This is one of those rare occasions where a turtle seems more beautiful on land than in water. This is also the first time in FFS history that a turtle at East Island has been matched to her foraging grounds by her facial markings. In addition, she is the first honu with a documented history prior to having received tags.

Conclusion

Hawaiian green turtles nest at the French Frigate Shoals every two to three years--a fact based on twenty-nine years of annual monitoring at FFS by NMFS. The Honokowai females follow this cycle. When egg-laying is complete, all five have reliably returned to the same home foraging grounds until their next urge to reproduce.

These records significantly contribute to continuing research in Hawaii suggesting that at least some green turtles demonstrate the same high degree of fidelity to certain coastal waters as they do to their distant nesting beaches.

Literature cited

Work, T. W. and G. H. Balazs. 1999. Relating tumor score to hematology in green turtles with fibropapillomatosis in Hawaii. J Wild. Dis. 35(4):804-807.

Tables

All evaluations of tumor severity and overall turtle condition conducted according to Work and Balazs (1999).

Annual records for Tutu U521
1990 First sighted at the Turtle House. Tagged female. Tumors on both eyes and one tumor near tag on right front flipper. Overall Tumor Score Light
1991 --- Nesting, French Frigate Shoals. 6/1/91, 6/2/91, 6/16/91, 6/18/91, 7/1/91, 7/3/91, 7/4/91, 7/15/91, 7/16/91, 7/29/91, 8/12/91, 8/13/91
1992 Resighted at the Turtle House. All tumors improved. First Honokowai regression case.
1993 Resighted at the Turtle House. Read one tag for the first time. Regression continues.
1994 Nesting, French Frigate Shoals. 6/25/94. Resighted at Honokowai on August 25th. Eye tumors completely gone. Tumor on right front flipper barely noticeable. Regression continues.
1995 Resighted on second dive. Accepted our presence easily. Regression complete, no visible tumors. New tags read July 15. She is turtle U521 (left rear tag).
1996 --- Nesting, French Frigate Shoals. 6/15/96, 7/1/96, 7/2/96
1997 Resighted quickly as fourth turtle of the summer. Regression holds.
1998 Resighted July 3rd dive. Several white blemishes on neck and shoulders. Fear of FP relapse!
1999 Nesting, French Frigate Shoals. 6/8/99, 6/21/99, 6/23/99. Resighted at Honokowai on August 27.

Annual records for Tiamat 122C
1991 Retrospective analysis of videotape shows Tiamat resting at the Turtle House.
1992 A photograph shows Tiamat swimming in the distance.
1993 Resighted at the Turtle House several times this summer. Acclimated somewhat. Small tumor beginning in right eye. Overall Tumor Score Light.
1994 Resighted at Turtle House and Reef 2. Tumors growing on neck, shoulders, and in both eyes and mouth. Overall Tumor Score Moderate.
1995 Resighted at Turtle House. Eye tumors shrunken, mouth tumors nearly gone. Becoming fully acclimated. Possible regression. Overall Tumor Score Light.
1996 Resighted at Resting Site and accepted us immediately. All tumors gone. Regression confirmed. To celebrate we name her Tiamat.
1997 --- First time nesting, French Frigate Shoals. 5/30/97, 5/31/97, 6/13/97, 6/15/97, 6/16/97
1998 Resighted on our first dive, June 29th. New tags--122C, and "V 40" is engraved in the right hind portion of her carapace. NMFS notified. Regression holding.
1999 Resighted Tiamat during first week's diving. Judging by her girth, things are going well. Regression holding.

Annual records for McTaggert F765
1992 Nothing more than a left profile in a poor photo, but enough for identification.
1993 --- First time nesting, French Frigate Shoals. 6/3/93
1994 Regular visitor to the Turtle House. Named McTaggert in honour of new tags--F765. Tolerant of approach. No visible tumors.
1995 Resighted at Turtle House. Infrequent visitor this year. No visible tumors.
1996 --- Not sighted at Honokowai, not reported at French Frigate Shoals. Only female ever to go AWOL!
1997 Resighted on afternoon dive of July 3rd. Increasing in girth and regular visitor this summer. No visible tumors.
1998 Resighted July 9th at The Rock. Only seen twice. No visible tumors.
1999 --- Nesting, French Frigate Shoals. 6/21/99

Annual records for Mendelbrot U359
1993 First sighting: July 18th, Rest Site. Early FP in both eyes, several neck/shoulder tumors, cantaloupe-sized tumor under right front flipper. Named Mendelbrot.
1994 --- First time nesting, French Frigate Shoals. 6/12/94, 6/13/94, 6/25/94, 7/7/94
1995 Resighted at Rest Site with shiny new tags. Regression confirmed. Eyes tumor-free, large tumor under her right front flipper is shrunken and gray. Did not read tags.
1996 --- Nesting, French Frigate Shoals. 6/11/96, 6/12/96, 6/22/96, 6/23/96, 6/25/96, 6/26/96
1997 Resighted July 27th. "Armpit" tumor had shrunken further. Regression continues. Read tag U359. NMFS records show Mendelbrot nested in June '94, June '96.
1998 Nesting, French Frigate Shoals. 6/5/98, 6/6/98, 6/18/98, 6/19/98. June 29th, NMFS confirms Mendelbrot nested at French Frigate Shoals. August 16th, sighted at Reef 2, D 62 painted on right rear of carapace. Still regressing.
1999 Resighted July 22nd at her preferred spot on Reef 2. Seen later at the Turtle House. Tumor under right front flipper continues to shrink. Still regressing.

Annual records for Shredder A240
1991 --- Nesting, French Frigate Shoals. 5/26/91, 5/27/91, 5/28/91, 6/11/91, 6/24/91, 7/6/91, 7/7/91, 7/20/91, 8/1/91
1992 --- No data. Not seen at Honokowai, not seen at French Frigate Shoals.
1993 --- Nesting, French Frigate Shoals. 6/15/93, 6/16/93, 6/17/93, 6/29/93
1994 --- No data. Not seen at Honokowai, not seen at French Frigate Shoals.
1995 Extremely shy turtle, easily identified by mangled hind flippers. Finally let us get close enough to record her facial markings, our only way for a positive identification.
1996 --- Nesting, French Frigate Shoals. 6/9/96, 6/21/96, 6/22/96, 7/3/96, 7/4/96
1997 Still shy, but allows us to read tags A240 and A 241. (Left profile unavailable.)
1998 --- Nesting, French Frigate Shoals. 6/7/98, 6/8/98, 6/9/98, 6/21/98
1999 1999 Resighted August 26th dive near North House. Only one resighting. Small tumor growing in posterior of each eye.


Who's Who Underwater at Honokowai

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