Dr. Godwin's Abstracts a, b, c, & d from his
Bibliographic Publications from 1989-1998

Abstract a: Godwin, J.R. and R.K. Kosaki. 1989. Reef fish assemblages on submerged lava flows of three different ages. Pacific Science 43(4): 289-301

Recent volcanic activity near Kapa'ahu, Hawaii provided an opportunity to survey reef fish assemblages on submarine lava flows of three ages: 0.3 yr, 32 yr, and prehistoric. The results are used to examine development of these assemblages and influence of habitat characteristics on species distributions. Community-level analysis found clear differences between sites. Overall adult abundance and species richness increased with the age of the flow, but juvenile densities were highest on the youngest flow. Differences in abundances shown by many species may relate to habitat characteristics such as food availability, shelter, and conspecific densities.
Abstract b: Godwin, J.R. and D.F. Fautin. 1992. Defense of host actinians by anemonefishes. Copeia 1992(3): 902-908.

Entacmaea quadricolor is the most common and geographically widespread host anemone. In this paper, we present strong support for the hypothesis that the anemonefish symbionts of E. quadricolor provide aggressive protection against anemone predators and assert that this symbiosis is therefore mutualistic. Observations suggesting that certain of the symbioses between other anemonefishes and actinians are also mutualistic are presented.
Abstract c: Godwin, J.R. and P. Thomas (1993). Sex change and steroid profiles in the protandrous anemonefish, Amphiprion melanopus. (Pomacentridae, Teleostei). General and Comparative Endocrinology 91: 144-157.

Plasma profiles of several gonadal steroids and cortisol were examined in a field population of the protandrous, sex-changing anemonefish Amphiprion melanopus to elucidate potential roles of these hormones in gonadal sex change. Sex change was experimentally induced in males by removal of their dominant female pair mates. These sex-changing males were captured and sampled at 5, 10, or 20 days after female removal. Unmanipulated males and females were also sampled. Males had higher plasma levels of 11-ketotestosterone (11-KT) than did females, but had lower levels of androstenedione (Ad), testosterone (T), and estradiol-17 beta (E2). The three androgens showed decreases from male levels at 10 days, then an increasing trend at 20 days after female removal. E2 levels exhibited no changes from male levels until 20 days, when a significant increase over male levels was observed. Mature females had higher levels of Ad, T, and E2 than the 20-day treatment group, indicating that these steroids continue to rise after Day 20. The results support hypothesized roles for androgens in male function and E2 in female function in A. melanopus. However, E2 increases lagged behind oogonial proliferation, arguing against an influence of this steroid in the initiation of female function. Cortisol levels did not differ between males and females, but exhibited an increase during sex change, peaking at 20 days.
Abstract d: Godwin, J.R. (1994). Histological aspects of protandrous sex change in the anemonefish Amphiprion melanopus. Journal of Zoology (Lond.) 232: 199-213.

Gonadal structure and cellular composition were examined in juveniles, males and females of the protandric hermaphrodite, Amphiprion melanopus. Functional sex change was experimentally induced in the field and gonad structure was histologically examined both qualitatively and quantitatively at 10, 20, 30 and 45 days after its initiation. Juvenile gonads consist primarily of immature ovarian tissue. Functional male gonads are ovotestes with co-existing mature spermatogenic tissue and immature ovarian tissue, while females possess only ovarian tissue. The initiation of sex change is marked by a rapid maturation of spermatogenic tissue and proliferation of putative oogonia. Gonads were essentially female by 20 days into sex change, but evidence of mature female function (marked by the initiation of vitellogenesis) was not observed until 45 days. Considerable variation between individuals was seen in quantitative measures of gonadal change in the early stages of sex change, but not in later stages. Progress in sex change as indicated by histological indicators was, however, consistent within stages. Duct systems for gamete transport changed from the male to the female form after all male tissue had been replaced.
End of subsite "jrgabs.a-d.html" for Dr. Godwin's Bibliographic Subsite, which you'll want to return to. Abstract subsite created for him 4-7-97 by J.Kemper. (http://www4.ncsu.edu/unity/users/g/godwin/www/jrgabs.a-d.html)