Estimates of body sizes at maturation and at sex change, and the spawning seasonality and sex ratio of the endemic Hawaiian grouper (Hyporthodus quernus, F. Epinephelidae)

A case study of the reproductive biology of the endemic Hawaiian grouper or hapu’upu’u (Hyporthodus quernus) is presented as a model for comprehensive future studies of economically important epinephelid groupers. Specimens were collected throughout multiple years (1978–81, 1992–93, and 2005–08) from most reefs and banks of the Northwestern Hawaiian Islands. The absence of small males, presence of atretic oocytes and brown bodies in testes of mature males, and both developed ovarian and testicular tissues in the gonads of five transitional fish provided evidence of protogynous hermaphroditism. No small mature males were collected, indicating that Hawaiian grouper are monandrous (all males are sex-changed females). Complementary microscopic criteria also were used to assign reproductive stage and estimate median body sizes (L50) at female sexual maturity and at adult sex change from female to male. The L50 at maturation and at sex change was 580 ±8 (95% confidence interval [CI]) mm total length (TL) and 895 ±20 mm TL, respectively. The adult sex ratio was strongly female biased (6:1). Spawning seasonality was described by using gonadosomatic indices. Females began ripening in the fall and remained ripe through April. A February–June main spawning period that followed peak ripening was deduced from the proportion of females whose ovaries contained hydrated oocytes, postovulatory follicles, or both. Testes weights were not affected by season; average testes weight was only about 0.2% of body weight—an order of magnitude smaller than that for ovaries that peaked at 1–3% of body weight. The species’ reproductive life history is discussed in relation to its management

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Predation, endemism, and related processes structuring shallow-water reef fish assemblages of the NWHI

Volume: 543Start Page: 237End Page: 25

National Oceanic and Atmospheric Administration Report 212

The following report is meant to evaluate whether the information on oocyte size improves ability to predict ovary weight from body weight, and we evaluate the cost-effectiveness of different sample sizes for characterizing egg size

Life history characteristics and status of the Pacific yellowtail emperor, Lethrinus atkinsoni (Seale 1910), in the Commonwealth of the Northern Mariana Islands

Abstract Life history characteristics of the Pacific yellowtail emperor, Lethrinus atkinsoni, were described from commercial samples in the Commonwealth of the Northern Mariana Islands spanning a 28‐month market sampling period. Derived statistics pertaining to growth, life span, mortality and reproductive features were obtained through analyses of sectioned sagittal otoliths and gonad tissues. Maximum age observed was 18 years, with females attaining 50% sexual maturity at 3.3 years at a fork length of 20.9 cm; too few male specimens precluded male maturation estimates. We concluded that the species exhibited an undetermined sexual pattern as no evidence of prior female function was observed in mature males. No annual spawning periods were identifiable. Early growth rates estimated by settlement size‐constrained VBGF models using fish landed by the nighttime commercial spear fishery (NCSF) were rapid. Exploitation rates indicated very low‐to‐moderate levels of exploitation. Boat‐based fishing efforts from the NCSF captured the larger individuals of the species, whereas shore‐based efforts captured the vast majority of individuals representing sizes generally below that of the estimated 50% maturation level. Extensive fishery‐independent in situ diver observations indicated the species may have a restricted range. Expanded fishery‐dependent collection of L. atkinsoni specimens and studies of its movement ecology at Saipan would provide additional input for fishery management, as well as a formal stock assessment which juvenile‐biased catches indicate are necessary

National Oceanic and Atmospheric Administration Report 344

Report on "estimate body size at sexual maturity for Hawaiian spiny lobster and slipper lobster using all available fishery independent research catch data from 1986 to 2001." (pg. 1