Ron I. Eytan’s research while affiliated with Texas A&M University at Galveston and other places

Blennies are cryptobenthic reef fishes (CRFs) that occupy a critical functional group in the trophodynamics of their respective ecological systems and for many of these species there has been renewed interest in their diversity and evolution. Here we provide a robust larviculture methodology for a blenniids, that may have applications for both ornamental aquaculture and scientific research. Larval ontogeny, pigmentation, and allometric growth patterns including gape morphology of the Florida blenny Chasmodes saburrae from the northern Gulf of Mexico (GoM) are described from a complete larval series from hatch to settlement (notochord/standard length, NL/SL = 3.37–14.49 mm; 1–21 days post hatch, dph). Larvae were assigned intervals of development using a suite of morphological characters and allometric growth rates and inflection points of rate change were computed with piecewise linear regressions. Pigmentation and general patterns of development followed that of other blenniid species in the GoM. Growth of all but one morphometric character measured followed a positive allometric growth rate relative to size (NL/SL) after hatching and followed a mostly biphasic growth pattern with inflection points corresponding to phenotypic changes during notochord flexion or prior to settlement and the completion of metamorphosis. A feeding gape size of 26.6% that of maximum gape size was calculated using size at first feeding of prey items and used to estimate an optimized feeding protocol. Based on this gape informed diet, larger and more nutrient rich prey items may be implemented in the feeding protocol between four and eight days earlier than previous study recommends. Captive breeding techniques used during this study show the ease of blenniid larvae culture compared with that of most other marine teleost families and suggests that blenniid larvae may serve as sensible candidates for a model study group of marine teleosts.

The blennies, Acanthemblemaria spinosa (Chaenopsidae) and Enneanectes altivelis (Tripterygiidae) are representative members of two families spanning the deepest node of the Blennioidei tree. The mitogenomes of 16,507 bp for A. spinosa and 16,529 bp for E. altivelis each consisted of 37 genes and one control loop region. Phylogenetic analysis confirmed the placement of Chaenopsidae and Tripterygiidae within the Blenniiformes, however, there was instability in the placement of the triplefins between reconstruction methods, likely due to low taxon sampling. These mitogenomes represent an important milestone in uncovering relationships within Blenniiformes and Ovalentaria.

Demographic histories are largely understood to be a product of their environment, as populations expand or contract in response to major environmental changes. Deep-pelagic fishes inhabit one of the most temporally and spatially stable habitats on the planet, so they may be resistant to the demographic instability commonly reported in other marine habitats, but their demographic histories are poorly understood. We reconstructed the demographic histories of thirteen species of deep-pelagic fishes using mitochondrial and nuclear DNA sequence data. We uncovered widespread evidence of demographic expansion in our study species, a counterintuitive result bases on the nature of the deep-pelagic. The frequency-based methods detected potential demographic changes in eleven species, while the Extended Bayesian Skyline Plots were more conservative and identified population expansion in five species. The dates of expansion largely coincide with periods of warm sea-surface temperature at the northern and southern boundaries for the ranges these species inhabit. We suggest that this is the result of the pelagic larval phase shared by most deep-pelagic fishes, where the larvae inhabit the upper 200 meters. Changes in sea surface conditions likely alter the suitability of the habitat in a given region for the larval phase, affecting the species range and in turn population size. These results are critical to our understanding of how the deep-pelagic fish community will respond to future climatic changes.

The pelagic Gulf of Mexico (GoM) is a complex system of dynamic physical oceanography (western boundary current, mesoscale eddies), high biological diversity, and community integration via diel vertical migration and lateral advection. Humans also heavily utilize this system, including its deep-sea components, for resource extraction, shipping, tourism, and other commercial activity. This utilization has had impacts, some with disastrous consequences. The Deepwater Horizon oil spill (DWHOS) occurred at a depth of ∼1500 m (Macondo wellhead), creating a persistent and toxic mixture of hydrocarbons and dispersant in the deep-pelagic (water column below 200 m depth) habitat. In order to assess the impacts of the DWHOS on this habitat, two large-scale research programs, described herein, were designed and executed. These programs, ONSAP and DEEPEND, aimed to quantitatively characterize the oceanic ecosystem of the northern GoM and to establish a time-series with which natural and anthropogenic changes could be detected. The approach was multi-disciplinary in nature and included in situ sampling, acoustic sensing, water column profiling and sampling, satellite remote sensing, AUV sensing, numerical modeling, genetic sequencing, and biogeochemical analyses. The synergy of these methodologies has provided new and unprecedented perspectives of an oceanic ecosystem with respect to composition, connectivity, drivers, and variability.

Acanthemblemaria aceroi new species is described from the upwelling region of the Caribbean coasts of Venezuela and Colombia. It differs from its closest relative, Acanthemblemaria rivasi Stephens, 1970, known from Panama and Costa Rica, in the posterior extent of the infraorbitals, details of head spination, and unique COI sequences. The description of Acanthemblemaria johnsonsi Almany & Baldwin, 1996, heretofore known only from Tobago, is expanded based on specimens from islands offshore of eastern Venezuela.

Serratia marcescens is a Gram-negative bacterium causally linked to acroporid serratiosis, a form of white pox disease implicated in the decline of elkhorn corals. We report draft genomes of 38 S. marcescens isolates collected from host and nonhost sources. The availability of these genomes will aid future analyses of acroporid serratiosis.

The deep waters of the open ocean represent a major frontier in exploration and scientific understanding. However, modern technological and computational tools are making the deep ocean more accessible than ever before by facilitating increasingly sophisticated studies of deep ocean ecosystems. Here, we describe some of the cutting-edge technologies that have been employed by the Deep Pelagic Nekton Dynamics of the Gulf of Mexico (DEEPEND; www.deependconsortium.org) Consortium to study the biodiverse fauna and dynamic physical-chemical environment of the offshore Gulf of Mexico (GoM) from 0 - 1500 m. Available from: https://doi.org/10.4031/MTSJ.52.6.10