John D. Baldwin

High connectivity on a global scale in the pelagic wahoo, Acanthocybium solandri (tuna family Scombridae)

The population genetic structure and phylogeography of wahoo, Acanthocybium solandri, were investigated on a global scale with intron six of lactate dehydrogenase‐A (ldhA6, 8 locations, N = 213) and mtDNA cytochrome b (Cytb, 10 locations, N = 322). Results show extensive sharing of haplotypes across the wahoos entire global range, and analyses were unable to detect significant structure (nuclear FST = 0.0125, P = 0.106; mtDNA ΦST < 0.0001, P = 0.634). Power analyses indicated 95% confidence in detecting nuclear FST ≥ 0.0389 and mtDNA ΦST ≥ 0.0148. These findings appear unique, as most other tunas, billfishes, and oceanic sharks exhibit significant population structure on the scale of East–West Atlantic, Atlantic vs. Indian‐Pacific, or East–West Pacific. Overall nuclear heterozygosity (H = 0.714) and mtDNA haplotype diversity (h = 0.918) are both high in wahoo, while overall mtDNA nucleotide diversity (π= 0.006) and nuclear nucleotide diversity (π=0.004) are uniformly low, indicating a recent increase in population size. Coalescence analyses yield an estimate of effective female population size (NeF) at ~816 000, and a population bottleneck ~690 000 years ago. However, conclusions about population history from our Cytb data set are not concordant with a control region survey, a finding that will require further investigation. This is the first example of a vertebrate with a single globally distributed population, a finding we attribute to extensive dispersal at all life stages. The indications of a worldwide stock for wahoo reinforce the mandate for international cooperation on fisheries issues.

Preliminary Observations of Topical Gill Application of Reproductive Hormones for Induced Spawning of a Tropical Ornamental Fish

Abstract Hormone injection is a common spawning induction technique in aquaculture but is of limited use in small species with low fecundity. An alternative to injection for such species is topical gill application. We conducted an experiment with female rainbow sharks Epalzeorhynchos erythrurus (Cyprinidae) in one control group and three treatment groups: (1) topical gill application of dimethyl sulfoxide (DMSO), (2) topical gill application of DMSO and Ovaprim, and (3) an Ovaprim intramuscular (IM) injection. Ovaprim contains a salmonid gonadotropin-releasing hormone analog and a dopamine antagonist. Fish were anesthetized, treated, and placed into recovery tanks. Fish were manually checked for ovulation by exerting abdominal pressure at 8, 10, and 11 h posttreatment and were observed for mortality during a 24-h period. Ovulation varied significantly: we found no ovulation of females in the control or DMSO groups, 78% ovulation in the DMSO plus Ovaprim group, and 100% ovulation in the Ovaprim IM injecti...

Long-Term Changes, 1958–2010, In the Reproduction of Bald Eagles of Florida Bay, Southern Coastal Everglades

Abstract The population of Bald Eagles (Haliaeetus leucocephalus) breeding in Florida Bay, located within Everglades National Park, has been the subject of one of the longest running monitoring programs for any large raptor species worldwide, with reproductive data collected for 49 breeding seasons since 1958. The overall reproductive trends in this nesting population indicated that the population has transitioned from one at or near carrying capacity to one in decline, with territory occupancy decreasing as much as 43%. This contrasted with observed trends for the state of Florida, where populations increased >300% over the past 25 yr. The rate of nesting attempts in Florida Bay remained high (0.83 ± 0.11 [SD]; number of active territories/number of occupied territories) over the period. Mean annualized brood size was 1.48 ± 0.16 young/successful territory and mean productivity was 0.81 ± 0.21 young/occupied territory, which are comparable to those of other Bald Eagle populations. There were significant increases in ratios of active territories/occupied territories, successful territories/occupied territories, and young/occupied territory, despite decreased occupancy. Increases in these rates have allowed overall production of the Florida Bay population to remain stable; however, given the current decreasing trend in territory occupancy, this population should be considered at risk. Changes in Bald Eagle reproductive parameters corresponded with significant ecological changes documented in Florida Bay and southern coastal Everglades and may serve as possible long-term indicators for the health and recovery of the southern Everglades as restoration efforts progress.

Molecular assessment of mating strategies in a population of Atlantic spotted dolphins.

Similar to other small cetacean species, Atlantic spotted dolphins (Stenella frontalis) have been the object of concentrated behavioral study. Although mating and courtship behaviors occur often and the social structure of the population is well-studied, the genetic mating system of the species is unknown. To assess the genetic mating system, we genotyped females and their progeny at ten microsatellite loci. Genotype analysis provided estimates of the minimum number of male sires necessary to account for the allelic diversity observed among the progeny. Using the estimates of male sires, we determined whether females mated with the same or different males during independent estrus events. Using Gerud2.0, a minimum of two males was necessary to account for the genetic variation seen among progeny arrays of all tested females. ML-Relate assigned the most likely relationship between offspring pairs; half or full sibling. Relationship analysis supported the conservative male estimates of Gerud2.0 but in some cases, half or full sibling relationships between offspring could not be fully resolved. Integrating the results from Gerud2.0, ML-Relate with previous observational and paternity data, we constructed two-, three-, and four-male pedigree models for each genotyped female. Because increased genetic diversity of offspring may explain multi-male mating, we assessed the internal genetic relatedness of each offspring’s genotype to determine whether parent pairs of offspring were closely related. We found varying levels of internal relatedness ranging from unrelated to closely related (range -0.136–0.321). Because there are several hypothesized explanations for multi-male mating, we assessed our data to determine the most plausible explanation for multi-male mating in our study system. Our study indicated females may benefit from mating with multiple males by passing genes for long-term viability to their young.

Adjusted Diets of Bald Eagles (Haliaeetus leucocephalus) Breeding In An Altered Estuary

Abstract Diet of Bald Eagles (Haliaeetus leucocephalus) in the Florida Bay estuary was determined from prey remains from nest sites and used to evaluate differences between two time periods, the 1972 and 1973 breeding seasons compared with 2009 and 2010. Between these two time periods, Florida Bay underwent a well-documented series of ecological changes beginning in the late 1980s, which significantly altered the ecosystem. To examine the hypothesis that ecological changes may have shifted Bald Eagle diets, we compared 571 remains (30 species) collected in 1972/1973 from 21 nest sites, to 419 remains (22 species) collected sites in 2009/2010 from 11 nest sites. Fish made up the majority of prey in 1972/1973 and 2009/2010 (80.7% and 69.5% by number, respectively) and birds were second (15.8% and 29.1%). Hardhead catfish (Arius felis) skulls made up the majority of individual prey remains in both time periods (55% and 54%). Bald Eagles also ate significantly larger catfish in the 1972/1973 seasons, as the mean total skull length was 10% greater and estimated biomass was 35.7% greater. There was no difference in overall prey diversity between the two time periods; however, analysis of similarities showed prey composition differed. Mullet (Mugilidae), jack (Carangidae), Double-crested Cormorant (Phalacrocorax auritus), and Red-breasted Merganser (Mergus serrator) were the species that contributed most to the dissimilarities between time periods. We suggest that Florida Bays ecological and prey community changes during this time period influenced Bald Eagle diets.