The Ellis Island Effect: Invasive Species in the Mid-Atlantic

Global invasions of marine species often follow human migration pathways and primary commerce routes. Exploration, immigration, and commerce to the United States has created hot spots for invasive species to become established. In particular, Ellis Island served as a primary spot for European immigrants over the last century. During the last 3 years, we have documented for the first time four non-native hydrozoans in New Jersey using molecular techniques. Gonionemusvertens, Moerisiainkermanica, and Bougainvilliatriestinahave origins potentially linked to the Mediterranean indicating a potential group invasion from that region. Aequoreaaustralisis a Pacific hydrozoan whose origin pathway is yet unknown, but has now been documented in our region. As the benthic polyp stages of these species are diminutive

Assessment of Seagrass Plant Demography Within and Among Beds of Turtle Grass (Thalassia testudinum), Manatee Grass (Syringodium filiforme), and Shoal Grass (Halodule wrightii) From the Northern Gulf of Mexico

Variability in the demographic patterns of seagrasses may affect a variety of physical and biological processes in aquatic communities. We investigated seasonal seagrass demography, sediment size structure, and sediment organic carbon from two sites (north and south) in St. Joseph Bay, Florida, for Thalassia testudinum, Syringodium filiforme, and Halodule wrightii. Geologically, sands dominated both sites, but the south site had significantly greater proportions of fine and very fine sands, whereas the north site was dominated by coarse and medium sands. Within each site, demographic parameters were assessed for edge (\u3c1 m) and interior portions (\u3e10 m) of grass beds. The objective was to quantify within-habitat demographic characteristics and assess whether differences in plant biomass and shoot density existed between edge and interior portions. Results for T. testudinum showed significantly greater shoot density (P \u3c 0.05) and plant biomass (P \u3c 0.001) from interior portions of the bed than from the edge for the north site, but there were no significant differences for the south site. Syringodium filiforme showed significantly greater shoot density from bed interiors than from edges for both the north and south sites (P \u3c 0.0001, P \u3c 0.001, respectively) as well as plant biomass (P \u3c 0.0001, P \u3c 0.01, respectively). Halodule wrightii showed a similar response, with greater shoot densities from the north interior (P \u3c 0.008) and significantly greater plant biomass from interior portions of beds for both the north and south sites (P \u3c 0.003, P \u3c 0.01, respectively). Within-bay comparisons showed that plant biomass and shoot density were generally greater from the north site than from the south site for T. testudinum and H. wrightii, but the reverse was true for S. filiforme. Although sands dominated both sites, the south site showed greater percentages of finer sediments, and S. filiforme biomass has been shown to be inversely related to sediment size. Although we were unable to resolve within-habitat differences in sediment size structure, which may suggest sediment baffling and water velocity changes, we surmise that physical and sedimentary differences exist between edge and interior portions of seagrass beds. These differences may have dramatic effects on processes such as larval settlement, predator-prey interactions, and per unit area primary production. As such, further investigations into within-habitat variability and edge effects in plant demography and associated biological and physical processes are needed

Use of Diadema antillarum Spines by Juvenile Fish and Mysid Shrimp

This research has the following objectives: 1) identify the size structure of D. antillarum among 3 coastal bays of St. John, United States Virgin Islands and 2) determine relationships between urchin presence and spine utilization by fish and mysid shrimp

Assessment of Seagrass Floral Community Structure from Two Caribbean Marine Protected Areas

Seagrass communities represent spatially complex and biomass producing systems comprised of intermixed seagrass and algal species. We investigated shallow water communities from two Marine Protected Areas (MPAs) in the Caribbean: St. John, United States Virgin Islands and Cayos Cochinos, Honduras. St. John sites (4) lie within the Virgin Islands National Park and the Coral Reef National Monument and are designated within an UNESCO Biosphere Reserve. Honduran sites (4) lie within the designated Marine National Monument. Our results indicate that both MPAs were dominated by Thalassia testudinum with spatial coverage and shoot density significantly greater in Honduras. Many sites also showed substantial cover of Syringodium filiforme, which was significantly greater in St. John. Most major algal groups showed significant differences between MPAs and among sites within locations. Specifically, Halimeda, Penicillus, Udotea, Galaxaura, and Dictyosphaeria were significantly more abundant in Honduras, while Padina and Avrainvillea were significantly greater from St. John. Additionally, only Honduran sites showed the presence of coral colonies (Montastrea and Porites) within their seagrass beds. Floral community level analyses demonstrated significant differences among almost all site comparisons suggesting relatively distinct floral communities exist within each of these regions, but both MPAs maintain high spatial coverage of seagrasses providing critical ecosystem services

Relationship Between Pea Crab (Pinnotheres maculatus) Parasitism and Gonad Mass of the Bay Scallop (Argopecten irradians)

We investigated the prevalence of pea crabs (Pinnotheres maculatus) in bay scallops (Argopecten irradians) from 1994 through 1996 in a scallop population from St. Joseph Bay, Florida. We also assessed their impacts on scallop reproductive potential. Our results showed that prevalence in bay scallops varied between 0 and 20% and were extremely low during 1996 (\u3c2%). Comparing Gonadal-Somatic Indices (GSI) between infested and non-infested bay scallops in samples assessed the impact of pinnotherid parasitism. Results showed that GSI was significantly reduced in infested individuals compared to non-infested individuals of the same size range (t12 = 2.3, P \u3c0.04). These results suggest that P. maculatus infestation may lower the reproductive potential of individual scallops, but the low rates of parasitism may only minimally impact the host population

First occurrence of the invasive hydrozoan Gonionemus vertens A. Agassiz, 1862 (Cnidaria: Hydrozoa) in New Jersey, USA

Gonionemus vertens A. Agassiz, 1862 is a small hydrozoan native to the Pacific Ocean. It has become established in the northern and southern Atlantic Ocean as well as the Mediterranean Sea. We report on the first occurrence of this species in estuaries in New Jersey, USA,and confirm species identification through molecular sequence analysis. Given the large number of individuals collected, we contend that this is a successful invasion into this region with established polyps. The remaining question is the vector and source of these newly established populations

A New Baseline for Diadema antillarum, Echinometra viridis, E. lucunter, and Eucidaris tribuloides Populations Within the Cayos Cochinos MPA, Honduras

We investigated the density of 4 urchin species from 5 shallow reefs in the Cayos Cochinos Marine Protected Area in Honduras. Individual species density varied among reefs with total urchin density ranging from 3.2–7.9 individuals/m2. Echinometra viridis (Agassiz, 1863) was the numerically dominant species (2.29/m2) followed by E. lucunter (Linnaeus, 1758) (1.76/m2) with Eucidaris tribuloides (Lamarck 1816) representing the fewest individuals (0.42/m2). Our results indicated that density of Diadema antillarum (Philippi, 1845) differed significantly among reefs (0.4-1.3/m2, mean = 0.63/m2), but are three times greater than data collected 12 years after the mass mortality event of the 1980’s. Size frequency analysis of D. antillarum indicated that test diameter also differed significantly among reef sites while correlation analysis showed that D. antillarum density was negatively related to both coral and algal cover. Echinometra viridis density, however, was positively related to coral cover (p \u3c 0.05). When all urchins were combined, they showed a negative correlation with algal cover and a positive correlation with coral cover indicating a potential top-down effect within the reefs. While urchin densities remain relatively low compared to other sites in the Caribbean, the D. antillarum population appears to be recovering in this Honduran MPA. If overall grazer abundance continues to increase then they may limit macroalgae on reefs, thereby encouraging coral settlement

qPCR Detection of Early Life History Stage Chrysaora quinquecirrha (Sea Nettles) in Barnegat Bay, New Jersey

The sea nettle Chrysaora quinquecirrha has become abundant in the Barnegat Bay estuary and frequently blooms in warm summer months. Various factors have been attributed to the increasing localized appearance of sea nettles and other jellyfish including eutrophication, overfishing, global warming, construction, and species introduction. Despite its abundance and frequent distribution within estuarine systems, very little work has been done to detect and quantify the early life history stages of this organism. Free-swimming larval stages of C. quinquecirrha can be detected and quantified using a quantitative polymerase chain reaction assay specific for the C. quinquecirrha 16S ribosomal (r)DNA locus of the mitochondrial DNA. This assay is species specific, linear over a 9-log range, and can detect as few as 10 copies of 16S rDNA. Twenty-liter field samples were sequentially filtered through 500- and 100-µm mesh to separate ephyra from planula larvae and gametes, respectively. Quantifiable levels of C. quinquecirrha 16S rDNA were detected at all eight paired locations in Barnegat Bay, with levels varying on both spatial and temporal scales. This research is apparently the first comprehensive field-based survey mapping, both spatially and temporally, the early life history stages of a scyphozoan in a major estuary using environmental DNA. Quantitative molecular data on the distribution of early stage C. quinquecirrha may prove useful in both understanding and managing blooms of sea nettles in Barnegat Bay

Decadal Changes in Hydrozoan Community Structure

In response to two noticeable blooms in gelatinous zooplankton following Hurricane Sandy and the closure of the Oyster Creek Nuclear Generating Station, a continual jellyfish community evaluation has been conducted in Barnegat Bay, NJ, since 2012. Plankton tows and lift nets were used at various sites throughout the bay to sample organisms and collect density data. Initially, the community was dominated by the scyphozoan Chrysaora chesapeakei and the ctenophore Mnemiopsis leidyi, both of which contributed to great reductions in other gelatinous species. When Hurricane Sandy struck the western Mid-Atlantic coast in 2012, disturbances to aquatic communities caused a significant decrease in C. chesapeakei densities in subsequent years, resulting in the growth and expansion of numerous hydrozoans species including Turritopsis dohrnii, Nemopsis bachei, Rathkea spp., and Gonionemus vertens. When the Oyster Creek Nuclear Generating Station was shut down in 2018—whose operation for over 50 years had negatively impacted Barnegat Bay through cooling system mortalities and significant thermal loading—we again saw an emergence of several key hydrozoans including T. dohrnii, as well as other non-native hydrozoans including Eucheilota maculata and Aequora australis; significant increases were especially noted for N. bachei. The combined freedom from predation, and destruction and stress from the power plant has led to the emergence of a robust hydrozoan medusae community in Barnegat Bay. What is unknown is whether the continued recovery of the apex predator C. chesapeakei will cause future declines in the abundance and distribution of hydrozoan medusae

Utilization Of Sea Scallop (\u3ci\u3ePlacopecten magellanicus\u3c/i\u3e Gmelin) Microsatellite Markers For Phylogenetic Applications In Bay Scallops (\u3ci\u3eArgopecten irradians\u3c/i\u3e Lamarck)

In previous research, microsatellite markers have been used to geographically and phylogenetically characterize and identify populations of sea scallops (Placopecten magellanicus Gmelin). Given that sea scallops are a closely related species to bay scallops (Argopecten irradians Lamarck), we have investigated whether the flanking DNA sequences of sea scallop microsatellite loci have been conserved in the bay scallop. We found that in all seven sets of published sea scallop PCR primers (Pma130, -132, -135, -180, -200, -212, and -275) that were tested with bay scallop DNA, there was sequence conservation and amplification of microsatellite regions. Our initial phylogenetic analyses, combined with the lack of any null alleles in bay scallops for the tested loci, confirm the close genetic distance between bay and sea scallops. These “new” bay scallop primers can be employed in future studies examining both natural and cultured populations of bay scallop and further inquiries into the phylogeny between bay and sea scallops