The use of large artificial reefs to enhance fish populations at different depths in the Florida Keys

This study showed that large prefabricated units and concrete rubble patch reefs, placed as artificial marine habitats on sand bottom, greatly enhance the abundance, diversity, and biomass of fish in an area. Densities of individuals and biomass were found considerably higher at artificial reefs than at nearby, natural, bank reefs, a result consistent with other studies. Location, depth, and vertical profile are important factors determining fish assemblages at artificial habitats in the Keys. Fishes were both produced at artificial reefs and attracted from the surrounding area. Fish assemblages at the Hawk Channel artificial reefs were considerably different from those on the offshore reef tract, particularly in terms of dominant species. Rescue of the original 1992 work in 2005 was funded by the South Florida Ecosystem Restoration Prediction and Modeling Program.

Feeding on protists and particulates by the leptocephali of the worm eels Myrophis spp. (Teleostei: Anguilliformes: Ophichthidae), and the potential energy contribution of large aloricate protozoa

The food sources of the leptocephali of the teleostean superorder Elopomorpha have been controversial, yet observations on the leptocephali of the worm eels, Myrophis spp. (family Ophichthidae) collected in the northern Gulf of Mexico indicate active, not passive, feeding. Leptocephali had protists in their alimentary canals. Estimates of the physiological energetics of worm eels indicate that large aloricate protozoa including ciliates could provide substantial energy to these leptocephali toward the end of the premetamorphic and metamorphic stages, given the low energy requirements of metamorphosing leptocephali. Global ocean warming will likely force a shift in oceanic food webs; a shift away from large protozoa toward smaller protists is possible. Such a disruption of the oceanic food webs could further compromise the survival of leptocephali.

Southern California's megaflood event of ca. 1605 AD linked to large-scale atmospheric forcing

A distinct, 1- to 2-cm-thick flood deposit found in Santa Barbara Basin with a varve-date of 1605 AD ± 5 years testifies to an intensity of precipitation that remains unmatched for later periods when historical or instrumental records can be compared against the varve record. The 1605 AD ± 5 event correlates well with Enzel's (1992) finding of a Silver Lake playa perennial lake at the terminus of the Mojave River (carbon-14-dated 1560 AD ± 90 years), in relative proximity to the rainfall catchment area draining into Santa Barbara Basin. According to Enzel, such a persistent flooding of the Silver Lake playa occurred only once during the last 3,500 years and required a sequence of floods, each comparable in magnitude to the largest floods in the modern record. To gain confidence in dating of the 1605 AD ± 5 event, we compare Southern California's sedimentary evidence against historical reports and multi-proxy time-series that indicate unusual climatic events or are sensitive to changes in large-scale atmospheric circulation patterns. The emerging pattern supports previous suggestions that the first decade of the 17th century was marked by a rapid cooling of the Northern Hemisphere, with some indications for global coverage. A burst of volcanism and the occurrence of El Nino seem to have contributed to the severity of the events. The synopsis of the 1605 AD ± 5 years flood deposit in Santa Barbara Basin, the substantial freshwater body at Silver Lake playa, and much additional paleoclimatic, global evidence testifies for an equatorward shift of global wind patterns as the world experienced an interval of rapid, intense, and widespread cooling.

Work plan for analytical support of an integrated ecosystem assessment of the California Current Large Marine Ecosystem, FY11 ‐ FY13

NOAA/NCCOS is conducting the following work for the NOAA California Current Integrated Ecosystem Assessment, in support of the NOAA/NMFS Northwest Fisheries Science Center.

Diet composition of large striped bass (Morone saxatilis) in Chesapeake Bay

Large (>458 mm) striped bass (Morone saxatilis) are dominant predators in Chesapeake Bay. In recent years, the Chesapeake Bay stock of striped bass has increased dramatically, raising concerns about their predatory impact and their forage requirements. In response to these concerns and the need for more recent ecological studies, this investigation was conducted to characterize feeding habits of large striped bass in Chesapeake Bay. Stomach contents from 1225 striped bass from 458 to 1151 mm TL were examined in the spring and fall of 1997 and 1998. Striped bass consumed 52 different species of vertebrates and invertebrates; however, only a few species of clupeoid and sciaenid fishes dominated diets across both the seasons and size ranges of striped bass examined. Of finfish species, menhaden (Brevoortia tyrannus) was the dominant prey in most areas and gizzard shad (Dorosoma cepedianum) replaced menhaden in importance in lower salinity waters. Spot (Leiostomus xanthurus) and other sciaenid fishes and anadromous herrings (Alosa spp.) also contibuted large percentages of striped bass diet. Although pelagic schooling fishes formed the majority of the diet, benthic fishes contributed a higher percentage to the diet than in previous studies of striped bass diet composition.

Scales of spatial variation in demography of a large coral-reef fish: an exception to the typical model?

Spatial variation in demographic parameters of the red throat emperor (Lethrinus miniatus) was examined among 12 coral reefs in three geographic regions (Townsville, Mackay, and Storm Cay) spanning over 3° of latitude of the Great Barrier Reef, Australia. Estimates of demographic parameters were based on age estimates from counts of annuli in whole otoliths because there was no significant difference in age estimates between whole and sectioned otoliths. There were significant regional differences in age structures, rates of somatic and otolith growth, and total mortality. The Townsville region was characterized by the greatest proportion of older fish, the smallest maximum size, and the lowest rates of otolith growth and total mortality. In contrast the Mackay region was characterized by the highest proportion of younger fish, the largest maximum size, and the highest rates of otolith growth and total mortality. Demographic parameters for the Storm Cay region were intermediate between the other two regions. Historic differences in fishing pressure and regional differences in productivity are two alternative hypotheses given to explain the regional patterns in demographic parameters. All demographic parameters were similar among the four reefs within each region. Thus, subpopulations with relatively homogeneous demographic parameters occurred on scales of reef clusters. Previous studies, by contrast, have found substantial between-reef variation in demographic parameters within regions. Thus spatial variation in demographic parameters for L. miniatus may differ from what is assumed typical for a coral-reef fish metapopulation.