National Marine Fisheries Service

About: National Marine Fisheries Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Population & Fisheries management. The organization has 3949 authors who have published 7053 publications receiving 305073 citations. The organization is also known as: NOAA Fisheries & NOAA National Marine Fisheries Service.

Regionally isolated populations of an imperiled Caribbean coral, Acropora palmata.

Abstract: The movements of larvae between marine populations are difficult to follow directly and have been the subject of much controversy, especially in the Caribbean. The debate centres on the degree to which populations are demographically open, such that depleted populations can be replenished by recruitment from distant healthy populations, or demographically closed and thus in need of local management. Given the depressed state of many tropical reef populations, the understanding of these movements now bears critically on the number, placement, and size of marine reserves. Most genetic analyses assume that dispersal patterns have been stable for thousands of generations, thus they commonly reflect past colonization histories more than ongoing dispersal. Recently developed multilocus genotyping approaches, however, have the demonstrated ability to detect both migration and population isolation over far shorter timescales. Previously, we developed five microsatellite markers and demonstrated them to be both Mendelian and coral-specific. Using these markers and Bayesian analyses, we show here that populations of the imperiled reef-building coral, Acropora palmata, have experienced little or no recent genetic exchange between the western and the eastern Caribbean. Puerto Rico is identified as an area of mixing between the two subregions. As a consequence of this regional isolation, populations in the western and eastern Caribbean should have the potential to adapt to local conditions and will require population-specific management strategies.

Locomotor Patterns in the Evolution of Actinopterygian Fishes

Abstract: SYNOPSIS. Locomotor adaptations in actinopterygian fishes are described for (a) caudal propulsion, used in cruising and sprint swimming, acceleration, and fast turns and (b) median and paired fin propulsion used for slow swimming and in precise maneuver. Caudal swimming is subdivided into steady (time independent) and unsteady (time dependent acceleration and turning) locomotion. High power caudal propulsion is the major theme in actinopterygian swimming morphology because of its role in predator evasion and food capture. Non-caudal slow swimming appears to be secondary and is not exploited before the Acanthopterygii. Optimal morphological requirements for unsteady swimming are (a) large caudal fin and general body area, (b) deep caudal peduncle, often enhanced by posterior dorsal and anal fins, (c) an anterior stabilizing body mass and\or added mass, (d) flexible body and (e) large ratio of muscle mass to body mass. Optimal morphological requirements for steady swimming are (a) high aspect ratio caudal fin, (b) narrow caudal peduncle, (c) small total caudal area, (d) anterior stabilizing body mass and added mass, and (e) a stiff body. Small changes in morphology can have large effects on performance. Exclusive morphological requirements for steady versus unsteady swimming are partially overcome using collapsible fins, but compromises remain necessary. Morphologies favoring unsteady performance are a recurring theme in actinopterygian evolution. Successive radiations at chondrostean, halecostome and teleostean levels are associated with modifications in the axial and caudal skeleton. Strength of ossified structures probably limited maximum propulsion forces early in actinopterygian evolution, so that specializations for fast cruising (carangiform and thunmform modes) followed structural advances especially in the caudal skeleton. No such limits apply to eel-like forms which consequently recur in successive actinopterygian radiations. Slow swimming using mainly non-caudal propulsion probably first occurred among neopterygians in association with reduced and neutral buoyancy. Slow swimming adaptations can add to and extend the scope of caudal swimming, but specialization is associated with reduced caudal swimming performance. Marked exploitation of slow swimming opportunities does not occur prior to the anterodorsal location of pectoral and pelvic girdles and the vertical rotation of the base of the pectoral fin, as found in the Acanthopterygii.

Oxidation of humic substances by manganese oxides yields low-molecular-weight organic substrates

Abstract: MANY bacteria oxidize thermodynamically unstable manganese(II) to Mn oxides and deposit the oxides on their surfaces1,2, a process that appears to account for most Mn oxidation in natural waters3–5 and sediments6. Among the reasons that have been proposed for the evolutionary selection of this process are protection from damage by toxic metals and oxygen species, protection from ultraviolet light, and strengthening of the bacterial sheath or capsule1,7. Mn oxides may promote harmful free radical reactions, however, and marine Mn-oxidizing bacteria are particularly susceptible to photoinhibition8. Here we report that Mn oxides lyse complex humic substances, which in general cannot be used by microorganisms directly9–11, to form low-molecular-weight organic compounds that can be used as substrates for microbial growth. Mn-oxidizing bacteria may thus be able to use the carbon pool in humic substances, which represent one of the largest organic reservoirs in natural waters, sediments and soils.

Pacific salmon extinctions: quantifying lost and remaining diversity.

Abstract: Widespread population extirpations and the consequent loss of ecological, genetic, and life-history diversity can lead to extinction of evolutionarily significant units (ESUs) and species. We attempted to systematically enumerate extinct Pacific salmon populations and characterize lost ecological, life history, and genetic diversity types among six species of Pacific salmon (Chinook [Oncorhynchus tshawytscha], sockeye [O. nerka], coho [O. kisutch], chum [O. keta], and pink salmon [O. gorbuscha] and steelhead trout [O. mykiss]) from the western contiguous United States. We estimated that, collectively, 29% of nearly 1400 historical populations of these six species have been lost from the Pacific Northwest and California since Euro-American contact. Across all species there was a highly significant difference in the proportion of population extinctions between coastal (0.14 extinct) and interior (0.55 extinct) regions. Sockeye salmon (which typically rely on lacustrine habitats for rearing) and stream-maturing Chinook salmon (which stay in freshwater for many months prior to spawning) had significantly higher proportional population losses than other species and maturation types. Aggregate losses of major ecological, life-history, and genetic biodiversity components across all species were estimated at 33%, 15%, and 27%, respectively. Collectively, we believe these population extirpations represent a loss of between 16% and 30% of all historical ESUs in the study area. On the other hand, over two-thirds of historical Pacific salmon populations in this area persist, and considerable diversity remains at all scales. Because over one-third of the remaining populations belong to threatened or endangered species listed under the U.S. Endangered Species Act, it is apparent that a critical juncture has been reached in efforts to preserve what remains of Pacific salmon diversity. It is also evident that persistence of existing, and evolution of future, diversity will depend on the ability of Pacific salmon to adapt to anthropogenically altered habitats.

Impacts of historical warming on marine fisheries production.

Abstract: Climate change is altering habitats for marine fishes and invertebrates, but the net effect of these changes on potential food production is unknown. We used temperature-dependent population models to measure the influence of warming on the productivity of 235 populations of 124 species in 38 ecoregions. Some populations responded significantly positively (n = 9 populations) and others responded significantly negatively (n = 19 populations) to warming, with the direction and magnitude of the response explained by ecoregion, taxonomy, life history, and exploitation history. Hindcasts indicate that the maximum sustainable yield of the evaluated populations decreased by 4.1% from 1930 to 2010, with five ecoregions experiencing losses of 15 to 35%. Outcomes of fisheries management-including long-term food provisioning-will be improved by accounting for changing productivity in a warmer ocean.