Michael D. Tringali

Marine Stock Enhancement in Florida: A Multi-Disciplinary, Stakeholder-Supported, Accountability-Based Approach

Saltwater fishery management in Florida, USA, is mandated to include user-supported hatchery-based stock enhancement. Scientists at the Florida Fish and Wildlife Conservation Commission and Mote Marine Laboratory have taken a multi-disciplinary, quantitative approach to develop effective strategies for integrating stocking into traditional fishery management, with an initial focus on red drum (Sciaenops ocellatus). With consensus from stakeholders, particularly from a well-informed advisory board, focus has shifted over the past 8 years from production-oriented stocking to an assessment-driven developmental approach. The goal is to develop and expand economically successful and ecologically sound stocking technology for rapidly replenishing depleted fish stocks in a multi-billion dollar (US) saltwater recreational fishing industry. Release-recapture experiments for red drum have been underway in Tampa Bay for 6 years. This research has involved replicate stratified releases of ∼ 4 million red drum hatchlings, which are identifiable via genetic testing. More than 20,000 red drum tissues have been tested. These were obtained from fishery-independent and dependent sampling and from an angler-return program,. Of these, approximately 3,000 specimens have been assigned to hatchery breeding pairs. Experimental results, especially those based on hatchery fish recruited to the recreational fishery, have provided managers with valuable information about size at release, release timing, release habitat, and post-release movement.

Permanent genetic resources added to Molecular Resources Database 1 February 2012 - 31 March 2012

This article documents the addition of 171 microsatellite marker loci and 27 pairs of single nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Bombus pauloensis, Cephalorhynchus heavisidii, Cercospora sojina, Harpyhaliaetus coronatus, Hordeum vulgare, Lachnolaimus maximus, Oceanodroma monteiroi, Puccinia striiformis f. sp. tritici, Rhea americana, Salmo salar, Salmo trutta, Schistocephalus solidus, Sousa plumbea and Tursiops aduncus. These loci were cross‐tested on the following species: Aquila heliaca, Bulweria bulwerii, Buteo buteo, Buteo swainsoni, Falco rusticolus, Haliaeetus albicilla, Halobaena caerulea, Hieraaetus fasciatus, Oceanodroma castro, Puccinia graminis f. sp. Tritici, Puccinia triticina, Rhea pennata and Schistocephalus pungitii. This article also documents the addition of 27 sequencing primer pairs for Puffinus baroli and Bulweria bulwerii and cross‐testing of these loci in Oceanodroma castro, Pelagodroma marina, Pelecanoides georgicus, Pelecanoides urinatrix, Thalassarche chrysostoma and Thalassarche melanophrys.

Genetic Management of Hatchery-Based Stock Enhancement

Including genetic considerations in stock enhancement can reduce the probability that enhanced (admixed) populations will undergo damaging genetic alteration through the stock enhancement effort. Avoiding alterations in genetic diversity, decreases in fitness, and reductions in effective population size (Ne) of admixed populations and their wild-population components is important for the long-term sustainability of those populations. Maintaining the genetic diversity of admixed populations and their wild-population components first requires managing both the genetic variability (e.g., numbers of alleles) and the genetic composition (frequencies of alleles) in the broodstocks and the broods. These genetic diversity components should be maintained at levels appropriate for each stock enhancement program throughout all aspects of stock enhancement—from broodstock selection through the rearing and releasing the broods and then, after release of the broods, in the admixed populations and their wild-population components until the admixed populations attain genetic equilibrium. Using small numbers of broodstock individuals, unequal contributions of broodstock individuals to broods, and inbreeding in broodstocks are common causes of alterations in genetic diversity. These pitfalls should be avoided because they can reduce genetic variability, change genetic composition, and increase genetic load (accumulation of deleterious alleles), which decreases the fitness hatchery broods. In an admixed population, reduction in the fitness of any population component (hatchery, wild, or their progeny) decreases the overall fitness of the admixed population. Hatchery brood fitness can also be reduced through outbreeding, which also ultimately decreases the fitness of the admixed population. Decreases in fitness of admixed populations or of any population components can extend over generations, particularly if stocking is repeated over multiple generations. The Ne of a population is directly related to losses in fitness due to inbreeding and reductions in genetic diversity. The smaller the Ne value of a population, the greater the chance that relatives will mate and that alleles (particularly rare alleles) will be lost over generations. Genetic monitoring programs for specific stock enhancement efforts Bert: Ecological and Genetic Implications ch08 Final Proof page 123 9.6.2007 11:40am Compositor Name: PDjeapradaban Theresa M. Bert (ed.), Ecological and Genetic Implications of Aquaculture Activities, 123–174.

Genetic Diversity Despite Population Collapse in a Critically Endangered Marine Fish: The Smalltooth Sawfish (Pristis pectinata)

Sawfish (family Pristidae) are among the most critically endangered marine fish in the world, yet very little is known about how genetic bottlenecks, genetic drift, and inbreeding depression may be affecting these elasmobranchs. In the US Atlantic, the smalltooth sawfish (Pristis pectinata) has declined to 1-5% of its abundance in the 1900s, and its core distribution has contracted to southwest Florida. We used 8 polymorphic microsatellite markers to show that this remnant population still exhibits high genetic diversity in terms of average allelic richness (18.23), average alleles per locus (18.75, standard deviation [SD] 6.6) and observed heterozygosity (0.43-0.98). Inbreeding is rare (mean individual internal relatedness = -0.02, SD 0.14; F(IS) = -0.011, 95% confidence interval [CI] = -0.039 to 0.011), even though the estimated effective population size (N(e)) is modest (250-350, 95% CI = 142-955). Simulations suggest that the remnant smalltooth sawfish population will probably retain >90% of its current genetic diversity over the next century even at the lower estimate of N(e). There is no evidence of a genetic bottleneck accompanying last centurys demographic bottleneck, and we discuss hypotheses that could explain this. We also discuss features of elasmobranch life history and population biology that could make them less vulnerable than other large marine vertebrates to genetic change associated with reduced population size.

Genetic Relationships among Populations of Florida Bass

Abstract Florida bass Micropterus floridanus are endemic to peninsular Florida and co-occur with largemouth bass M. salmoides in a natural intergrade zone in the northern portions of the state. In this study, we resolved the genetic population structure among populations of largemouth bass, Florida bass, and their interspecific hybrids from 48 lakes and streams across Florida, and we updated and refined the southernmost boundary of introgression. Nuclear (allozyme and microsatellite) and mitochondrial (restriction fragment length polymorphism) markers produced somewhat different results. Microsatellite genotypes alone and the combination of all nuclear genotypes resolved genetic structure among four regional groups within Florida: (1) northwest, (2) north-central, (3) central-west, and (4) south, central-east, and northeast. Allozyme genotypes alone did not resolve well-defined groups. The distribution of mitochondrial haplotypes suggested that populations from the St. Johns River drainage should be consi...

Limits to the Use of Contemporary Genetic Analyses in Delineating Biological Populations for Restocking and Stock Enhancement

Managers of restocking and stock enhancement programs have dual needs with respect to unit-stock identification: (1) identifying boundaries of genetically discrete stocks for responsible genetic management, and (2) delineating demographically discrete stocks. The reality, however, is that the temporal/spatial boundaries of genetic and demographic stocks may be discordant. Tagging data for the common snook, Centropomus undecimalis, show that there is little movement between Florida (FL) Gulf of Mexico and Atlantic waters. Nearly all snook from the Gulf inhabit a single estuary for their entire lives, whereas most Atlantic snook stray or emigrate much greater distances. A robust microsatellite DNA analysis of > 1,300 specimens confirmed the genetic distinctiveness of Gulf and Atlantic stocks. Curiously, there was no evidence of genetic structure within the Gulf stock. Inferring demographic stock boundaries using genetic data alone could lead to the erroneous conclusion that releases in a single Gulf estuary would eventually influence catch rates along the entire Gulf coast. Alternative methods for unit-stock identification and careful consideration of their inherent limitations are needed to identify the area over which demographic benefits or genetic impacts from releases of cultured juveniles can be expected.

Isolation and characterization of eighteen microsatellite loci for the largemouth bass, Micropterus salmoides, and cross amplification in congeneric species

We used a PCR-based technique to isolate 18 microsatellite loci for the largemouth bass, Micropterus salmoides. These loci were characterized using sampled populations in Florida and Wisconsin. The mean number of alleles at a locus was 8 for the sample from Florida and 5 for the samples from Wisconsin. The observed heterozygosities were 0.57 and 0.33 for the samples from Florida and Wisconsin, respectively. There was evidence of genetic differentiation between the Florida and Wisconsin samples at all 18 loci, indicating spatial structure within the range of M. salmoides. The markers cross-amplified in the seven other micropterid species, which suggests they would have utility for studies of hybridization among other members of the genus.

Ten di- and trinucleotide microsatellite loci in the Caribbean spiny lobster, Panulirus argus, for studies of regional population connectivity

We describe 10 microsatellite loci for Panulirus argus (Caribbean spiny lobster). The number of alleles at each locus ranged from four to 39 (mean = 21.8) in 89 juvenile specimens collected at two different times at a recruitment site in south Florida. Levels of expected and observed heterozygosities ranged from 0.48 to 0.96 (mean = 0.83) and from 0.32 to 0.98 (mean = 0.71), respectively. Significant departures from Hardy–Weinberg equilibrium were observed at two loci. There was no evidence of genotypic disequilibrium for any pair of loci. Overall, the loci were well resolved, highly polymorphic and independently segregating, confirming their utility for population genetic studies.

Genetic Identification of Centropomine Fishes

Abstract The purposes of this study were to evaluate the present species classification, to develop genetic methods for diagnosing morphologically indistinguishable juveniles, and to investigate the potential for introgressive hybridization for species of the percoid fish genus Centropomus (Pisces: Centropomidae). We analyzed specimens representing all nominal species using allozyme electrophoretic data and sequence data from a 618-base-pair portion of the mitochondrial DNA (mtDNA) 16S ribosomal RNA (rRNA) gene. Outgroup taxa from the confamilial genus Lates were also included. Results of the allozyme analysis, based on 27 presumed protein-coding gene loci, were in good agreement with the most recent taxonomic revision of the genus. All morphological species were identifiable by diagnostic allozyme loci except the largescale fat snook C. mexicanus (also known as the constantino snook), which was distinguishable from its sympatric sibling species, the fat snook C. parallelus by a significant allele frequen...

PERMANENT GENETIC RESOURCES: Eighteen new polymorphic microsatellite markers for the endangered Florida manatee, Trichechus manatus latirostris

Here we describe 18 polymorphic microsatellite loci for Trichechus manatus latirostris (Florida manatee), isolated using a polymerase chain reaction‐based technique. The number of alleles at each locus ranged from two to four (mean = 2.5) in specimens from southwest (n = 58) and northeast (n = 58) Florida. Expected and observed heterozygosities ranged from 0.11 to 0.67 (mean = 0.35) and from 0.02 to 0.78 (mean = 0.34), respectively. Departures from Hardy–Weinberg equilibrium occurred at two loci. There was no evidence of genotypic disequilibrium for any pair of loci. For individual identification, mean random‐mating and θ‐corrected match probabilities were 9.36 × 10−7 and 1.95 × 10−6, respectively.