Evaluation of reproductive strategies in captive California yellowtail (Seriola dorsalis) using genetic parentage analyses

A good understanding of spawning dynamics of species in aquaculture is vital in order to maximize egg production and quality as well as efficient allocation of food and space resources. The breeding program of California yellowtail (CYT; Seriola dorsalis previously Seriola lalandi) at Hubbs-SeaWorld Research Institute (HSWRI) is set up such that up to 30 wild caught brood fish can broadcast spawn in a group setting, just as CYT reproduce in the wild. The population of brood fish were originally caught offshore from Southern California, and are maintained under ambient sea water and natural lighting conditions. The spawning season at HSWRI lasted from March to September during the 2013 and 2014 study period. Reproductive output from this population of cultured CYT was evaluated through microsatellite-based parentage analyses whereby the percent contribution of offspring was determined across all spawning events over two years. Methods were first tested to determine the minimum sample size required to accurately describe the parental contributions in this specific group spawning environment. To do this, five spawns were selected from the 2013 season based on spawn volume, which was presumed to represent a high number of female parents thus representing the most complex spawning dynamic. For these five spawning events, there were 19 brood fish present, representing all possible parents. Actual assignment of samples sizes between 47 and over 300 was assessed for each spawn. Except in one instance, the parental contribution from sample size of 47 CYT offspring analyzed per spawn, was not statistically significantly different than a sample size of over 300 offspring per spawn (average P-value = 0.65). Simulated subsampling via computational bootstrapping, and subsequent statistical analysis, indicated that a sample size of 30 offspring per spawn was adequate to accurately describe the parental contributions. Based on this information, a samples size of 47 was used so that samples from two spawns could be run on a single 96 well plate, including one negative control sample per spawn. This constitutes one of the first studies of sample size quality control for genetic parentage contribution for an aquaculture species. Offspring were then analyzed from every spawning event (N = 130) over two spawning seasons to characterize spawning events of CYT. Analyzing all spawns during multiple spawning seasons allowed for determination of individual contribution levels, spawn pairings, and analysis of female fecundity. The breeding population consisted of 19 brood fish in 2013, and 37 in 2014; both years were roughly 50: 50 male – female. Brood fish added to the population in 2014 were smaller in terms of mass and total lengths. Spawning events tended to have one female contribute (primary female), with relatively equal paternal contribution during both the spawning events and season, for a possible lottery polygyny (Nunney, 1993) spawning system. One female in particular contributed 40% of all offspring during the two years, spawning nearly every 5-6 days during the spawning seasons. The larger females (~21 kg) had an average batch fecundity of ~490,000 eggs per spawn, while smaller females (~8.4 kg) only spawned 35,000 eggs per spawn. Annual and batch spawning totals were correlated to female mass (P \u3c 0.0005). All smaller brood fish spawned fewer times in the season than larger brood fish. This work constitutes the first-ever study of reproductive strategy (lottery polygyny) and parental contribution for a carangid species at the individual-level over several spawning events

Differences Among Older Adults in the Types of Dental Services Used in the United States

The purpose of this article is to explore differences in the socioeconomic, demographic characteristics of older adults in the United States with respect to their use of different types of dental care services. The 2008 Health and Retirement Study (HRS) collected information about patterns of dental care use and oral health from individuals aged 55 years and older in the United States. We analyze these data and explore patterns of service use by key characteristics before modeling the relationship between service use type and those characteristics. The most commonly used service category was fillings, inlays, or bonding, reported by 43.6% of those with any utilization. Just over one third of those with any utilization reported a visit for a crown, implant, or prosthesis, and one quarter reported a gum treatment or tooth extraction. The strongest consistent predictors of use type are denture, dentate, and oral health status along with dental insurance coverage and wealth. Our results provide insights into the need for public policies to address inequalities in access to dental services among an older US population. Our findings show that lower income, less wealthy elderly with poor oral health are more likely to not use any dental services rather than using only preventive dental care, and that cost prevents most non-users who say they need dental care from going to the dentist. These results suggest a serious access problem and one that ultimately produces even worse oral health and expensive major procedures for this population in the future