共查询到20条相似文献,搜索用时 31 毫秒
1.
Olive ridley sea turtles display two different types of nesting behavior: in arribada (synchronous mass nesting) or solitarily. Contrarily to arribadas, little has been published about solitary nesters. This study aimed to expand the knowledge on internesting interval and
site fidelity of solitary nesting olive ridleys and to test a possible development of arribada nesting behavior. Data were collected in Sergipe (Brazil) over 125 km of beach from 10°30′S/36o23′W to 11°26′S/37o19′W, between
nesting seasons 2004/2005 and 2006/2007. From 962 tagged females, 173 were seen renesting. The average internesting interval
found was longer (22.35 ± 7.01 days) than previously described, which might relate to lower water temperatures during the
internesting period. Olive ridleys at Sergipe showed high nesting site fidelity, with consecutive nesting events occurring
in close proximity, non-randomly and dependently of previous events. Most of the consecutive nests were separated by 4.06–5.59 km.
Development of arribada nesting behavior was not confirmed. 相似文献
2.
Joseph M. O’Malley 《Marine Biology》2011,158(8):1887-1901
Scaly slipper lobster (Scyllarides squammosus) population ecology was examined using tag/recapture information at Necker Island (23°30′N; 164°35′W), Gardner Pinnacles
(25°00′N; 168°50′W), Maro Reef (25°30′N; 170°45′W), and Laysan Island (25°48′N; 171°45′W) in the Northwestern Hawaiian Islands
(NWHI) USA from 2002 to 2008. Although many aspects of S. squammosus life history and population dynamics were similar to those of other scyllarids, somatic growth differed from its congers.
Scyllarides squammosus growth abruptly declined at maturity and, because of this, growth at length was better described using the Schnute as opposed
to the more commonly von Bertalanffy growth model. Growth varied among locations, and survival varied among years; thereby
being the first documentation of variability in the life history of a scyllarid. This study has expanded knowledge of scyllarid
biology and documented that spatiotemporal variability in biological characteristics must be considered to understand and
describe the population ecology of this species and probably of other scyllarids. 相似文献
3.
Understanding physiological and environmental variables that initiate sexual maturity would provide fundamental information
on life history dynamics. The aim of this study was to test the usefulness of the common circumnuclear ring (CNR), an oocytic
structure similar to the Balbiani body, which appears just prior to oocyte development as a predictor of first maturation
in Atlantic herring (Clupea harengus). The relative roles of physiology (e.g. fat) and photoperiod as triggers of maturation were also investigated. Samples were
collected in May 2008 (72°26′–73°84′N/11°26′–18°40′E) and February 2009 (56°12′–59°45′N/00°25′–03°06′W). These data suggested
that thresholds in body size may influence the decision to mature. We also found that short days (winter solstice) may be
the photoperiod trigger for a first-decision window for both Norwegian spring-spawning (NSS) and North Sea autumn-spawning
(NSAS) herring. The second-decision window for NSAS herring maturation appears to be triggered by longer days (spring equinox),
while a decreasing rate of day lengthening may trigger NSS herring maturation. So, photoperiodic cycle is a key determinate
of the timing of maturation in Atlantic herring. 相似文献
4.
Kelp gulls (Larus dominicanus) feed on pieces of skin and blubber they rip from Southern right whales’ (Eubalaena australis) backs in their breeding areas at Península Valdés, Argentina, producing injuries. This behavior has increased since the first record in 1972, and some authors have suggested that constant gull harassment could have a negative effect on right whale population. The main goal of this study is to assess the variables that most affect the gull attacks. We analyzed 5359 whale-watching sightings made during trips from Puerto Pirámides (42o34′S, 64o16′W) along the whale breeding seasons (June–December) 2005 to 2007. The most important factors affecting the attacks include the presence of a mother–calf pair, the time within the season, the distance to the coast and the wind velocity. There is also concern of possible transmission of infectious diseases in the attacks since increasing number of whales with different patterns of skin lesions have been observed. 相似文献
5.
Assignment of individuals to populations based upon genetic data is an important ecological problem that requires many polymorphic
markers, often more than are available using single locus techniques. To demonstrate the utility of amplified fragment length
polymorphisms (AFLP) in studying larval dispersal and recruitment in coral populations, two sets of AFLP primers were used
to genotype colonies of the coral Agaricia agaricites Linnaeus from three widely separated geographic locations: the Bahamas (23°28′N, 75°42′W) and Key Largo, Florida (24°55′N,
80°31′W—two sites separated by 12 km) in 1995, and the Flower Garden Banks (FGB) in the Gulf of Mexico (27°55′N,93°36′W) in
1997. In addition to adult samples from each site, recruits were collected from settling plates placed on the East FGB for
1 year (1997–1998). The AFLP technique yielded 45 polymorphic markers. An analysis of molecular variance (AMOVA) showed significant
genetic differences among the four adult populations, even between the two Key Largo sites. The recruits were significantly
different from all adult populations except those from the FGB. Discriminant function analysis and the program AFLPOP were
used to assign individuals to populations. Using the adult AFLP-banding patterns to build the statistical models, both procedures
correctly assigned the majority of adults to their respective populations in simulations and assigned all but one of the recruits
to the Flower Garden population from where they were collected . The AFLP technique provides a simple and adaptable population
assignment method for studying recruitment processes in A. agaricites and other coral species.
Electronic Supplementary Material Supplementary material is available for this article at 相似文献
6.
Mitochondrial cytochrome oxidase subunit one (COI) sequence, nuclear microsatellites, and amplified fragment length polymorphisms
(AFLPs) were used to evaluate connectivity among nine red abalone (Haliotis rufescens) populations sampled between August 1998 and November 2003 along approximately 1,300 km of California coastline from Crescent
City (41°46′N, 124°12′W) to San Miguel Island (34°02′N, 120°22′W). COI sequences and microsatellite genotypes did not show
significant genetic divergence among nine sampled populations. A subset of five populations spanning the geographic range
of the study was scored for 163 polymorphic AFLP markers. Of these, 41 loci showed significant divergence (P < 0.001) among populations. Still, no AFLP markers were diagnostic for any of the study populations, and assignment tests
did not consistently assign individuals to the correct population. Although the AFLP data are the first to suggest there is
significant genetic differentiation among California red abalone populations, the discordance between the different genetic
markers needs further study before unambiguous conclusions can be drawn with respect to connectivity among the populations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
During 2008 and 2009, an epidemic affected sponges of the genus Ircinia in the Western Mediterranean. Investigations at a site on the European coast (6o43′08.80′′N; 3o43′52.20′′W) and another on
the African coast (35o10′51.00′′N; 2o25′33.00′′W) revealed healthier African populations. The disease started with small pustules
on the sponge surface, which subsequently coalesced forming larger, extensive lesions. An ultrastructural study suggested
that a twisted rod is the etiological agent. It infected the sponges from the outside, initially killing the cells below the
ectosome and then penetrating deeper into the body. The sponges responded to the bacterial progression by secreting concentric
barriers of collagen and concentrating phagocytic cells at the diseased zones. This primitive immune system successfully resisted
the disease in many instances, although mortality reached 27% in the studied populations. Epidemic outbreaks recur each year
in September through November, arguably favored by abnormally high seawater temperatures in August. 相似文献
8.
Rocío Mariano-Jelicich Florencia Botto Paulina Martinetto Oscar Iribarne Marco Favero 《Marine Biology》2008,155(4):443-450
The degree of individual or gender variation when exploiting food resources is an important aspect in the study of foraging
ecology within a population. Previous information on non-breeding skimmers obtained through conventional methodologies suggested
sex-related differences in prey species. In this study, stable isotope techniques were used to investigate the intraspecific
segregation in diet and foraging habits of the Black Skimmer (Rynchops niger intercedens) at Mar Chiquita Coastal Lagoon (37°40′S, 57°22′W), Argentina. These results were compared with contemporary data on the
trophic composition obtained by conventional methodologies. Blood samples were taken from birds captured with mist-nets during
their non-breeding season. The isotopic signatures of skimmers showed a diet mainly composed of marine prey with some degree
of estuarine fish intake. When comparing diet between sexes, males showed enrichment in 15N compared to females, while no differences were observed in 13C. The use of mixing models revealed differences in the relative composition of prey in the diet of male and female skimmers.
This study highlights stable isotope analysis as a valuable tool to test inter-individual differences and sexual segregation
in trophic ecology of Black Skimmers as compared to conventional methodologies. The results show a trophic segregation in
the Black Skimmer during the non-breeding season that can be explained by differences in prey species and larger prey sizes
of male skimmers. Our findings have significant implications for conservation since any environmental change occurring at
wintering areas might have profound effects on several avian life-history traits, and could be different for males and females
due to trophic segregation. 相似文献
9.
Domoic acid in benthic flatfish on the continental shelf of Monterey Bay,California, USA 总被引:1,自引:0,他引:1
Within Monterey Bay, California, USA, the food web transfer of domoic acid (DA), a neurotoxin produced by diatoms of the genus
Pseudo-nitzschia, has led to major mortality events of marine mammals and birds. Less visible, and less well known, is whether invertebrates
and fish associated with the benthos are also affected by blooms of DA-producing Pseudo-nitzschia spp. This study examines the presence of DA in benthic flatfish offshore of Davenport, California, (37°0′36″N, 122°13′12″W)
and within Monterey Bay, California (36°45′0″N, 122°1′48″W), including species that feed primarily in the sediment (benthic-feeding)
and species that feed primarily in the water column (benthopelagic-feeding). Flatfish caught between 10 December 2002 and
17 November 2003 at depths of 30–180 m had concentrations of DA in the viscera ranging from 3 to 26 μg DA g−1 of viscera. Although the DA values reported are relatively low, benthic-feeding flatfish were frequently contaminated with
DA, especially as compared with the frequency of contamination of flatfish species that feed in the water column. Furthermore,
on days in which both benthic-feeding and benthopelagic-feeding flatfish were collected, the former had significantly higher
concentrations of DA in the viscera. Curlfin turbot, Pleuronicthys decurrens, the flatfish with both the highest level and frequency of DA contamination, are reported to feed exclusively on polychaetes,
suggesting that these invertebrates may be an important vector of the toxin in benthic communities and may pose a risk to
other benthic-feeding organisms.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Pat M. Fidopiastis Daniel J. Bezdek Michael H. Horn Judith S. Kandel 《Marine Biology》2006,148(3):631-642
The zebraperch, Hermosilla azurea Jenkins and Evermann, a warm-temperate marine fish species with a strictly macroalgal diet, has a relatively long digestive
tract with an enlarged hindgut and an associated blind caecum (HC). In zebraperch sampled off Santa Catalina Island, California
(33°19′42′′N; 118°18′37′′W) in years 1995 through 2001, direct cell counts, gut epithelium assessment of bacterial attachment,
and short-chain fatty acid (SCFA) analyses verified that the zebraperch HC possesses a dense and morphologically diverse,
fermentative microbiota. Bacterial cell counts and morphological diversity were significantly higher in HC contents compared
to anterior gut regions, suggesting that microbial populations were growing along the digestive tract. Similarly, electron
micrographs of the HC epithelium revealed attached microbes, further supporting the possibility that these organisms constitute
resident microbiota. Five different SCFAs were detected in all three regions of the digestive tract, but levels were up to
three times greater in HC contents. Acetate was consistently the prevailing SCFA in all gut regions. Sequence analysis of
bacterial 16S rDNA was used to identify predominant bacterial groups in HC contents. Of the seven main bacterial types identified,
Enterovibrio spp. were the dominant bacteria in HC contents followed by species of Bacteroides,Faecalibacterium, and Desulfovibrio. Taken together, our findings show that the zebraperch HC harbors a consortium of microbes that appears to assist in the
breakdown of algal polysaccharides in the herbivorous diet of the fish. 相似文献
11.
Field experiments were conducted from dusk to dawn off St. John (18° 18′ 59.32″ N, 64° 43′ 24.5″ W) and Guana Island (18°
28″ 28.31″ N, 64° 34′ 30.83″ W), Virgin Islands from June through August 2008-2010 to assess the sensory cues used by the
nocturnal/crepuscular fish-parasitic gnathiid isopod, Gnathia marleyi, to locate fish hosts. Experimental traps providing both visual and olfactory cues from live French grunts (Haemulon flavioliniatum) attracted significantly more gnathiids than traps providing only visual cues or control traps (empty or with a rock), which
were not significantly different from each other. In another experiment, traps providing both cues and only olfactory cues
attracted significantly more gnathiids than empty control traps, but were not significantly different from each other. Our
findings suggest that during nocturnal and crepuscular periods, visual cues provided by resting or slow-moving fish are not
alone sufficient to attract gnathiids, while olfactory cues alone are. The traps designed for this study offer a new method
of sampling free-living gnathiid isopods. 相似文献
12.
13.
Luis Américo Conti Carlos Alberto S. Araujo Fernando S. Paolo Roberto L. Barcellos Marcelo Rodrigues Michel M. Mahiques Valdenir V. Furtado 《Journal of Coastal Conservation》2012,16(1):13-24
The aim of this work is to use GIS integration data to characterize sedimentary processes in a SubTropical lagoon environment.
The study area was the Cananéia Inlet estuary in the southeastern section of the Cananéia Lagoon Estuarine System (CLES), state of S?o Paulo, Brazil (25°03′S/47°53′W). The area is formed by the confluence of two estuarine channels forming a
bay-shaped water body locally called “Trapandé Bay”. The region is surrounded by one of the most preserved tracts of Atlantic Rain Forest in Southwestern Brazil and presents
well-developed mangroves and marshes. In this study a methodology was developed using integrated a GIS database based on bottom
sediment parameters, geomorphological data, remote sensing images, Hidrodynamical Modeling data and geophysical parameters.
The sediment grain size parameters and the bottom morphology of the lagoon were also used to develop models of net sediment
transport pathways. It was possible to observe that the sediment transport vectors based on the grain size model had a good
correlation with the transport model based on the bottom topography features and Hydrodynamic model, especially in areas with
stronger energetic conditions, with a minor contribution of finer sediments. This relation is somewhat less evident near shallower
banks and depositional features. In these regions the organic matter contents in the sediments was a good complementary tool
for inferring the hydrodynamic and depositional conditions (i.e. primary productivity, sedimentation rates, sources, oxi-reduction rates). 相似文献
14.
Calcium carbonate transfer was experimentally examined in hydrothermal mussels Bathymodiolus azoricus, which were collected from 850 m depth at Menez Gwen hydrothermal vent site (31°31′W, 37°50′N) on the Mid Atlantic Ridge in
May 2007. In each of four 10-day experiments, groups of mussels were maintained at atmospheric pressure or re-pressurised
to depths relevant to their site of occurrence, i.e. 850 m depth at Menez Gwen, 1,750 m at Lucky Strike (31°31′W, 37°18′N)
and 2,300 m at Rainbow (31°31′W, 36°13′N). The shells of experimental mussels were perforated and mantle tissue was fixed
for light and TEM studies at days 7 and 10 following the injury. Simultaneously, haemocytes from the extrapallial fluid (EPF)
at the site of induction were studied. At day 7 the response was most intense in the middle fold of the mantle margin and
possibly proportional to hydrostatic pressure. At day 10 the epithelial cells on the mantle surface facing the body cavity
produced copious organic secretions that avidly bound calcium. Haemocyte migration was noted within the mantle tissue, and
the haemocytes at the mantle surface facing the shell had a Ca-positive granular content. Large haemocytes were detected in
the EPF at the injury site, and some showed evidence of an immune reaction while others showed Ca-positive granular content.
These results suggest that haemocytes are involved in shell repair in these deep-sea mussels just as in some freshwater and
shallow marine molluscs. 相似文献
15.
The amount of food and when it is available affect both the timing of reproduction and the number of gametes produced by purple
sea urchins, Strongylocentrotus purpuratus. To investigate this further, the effects of food availability on feeding rates, gonad growth, and gamete development were
examined in S. purpuratus collected from the Point Loma kelp forest near San Diego, California, USA (32.69° N, 117.26° W) in September (Fall) 2007,
and February (Spring) and July (Summer) 2008, using laboratory mesocosms. Each seasonal laboratory feeding experiment lasted
3 months, and different levels of food availability were established with different feeding frequencies (from 1 to 7 days
week−1). Gonad tissues of male and female urchins were staged at the end of each experiment using histological analyses. Reduced
food availability resulted in increased daily consumption rates, especially in the Fall when gamete development began. Food
limitation at this time resulted in failure to produce viable gametes, suggesting there is a critical period early in gonad
development when food limitation affects reproductive competency. Food limitation later in gonad development did not stop
viable gamete production, although it did reduce gamete output. 相似文献
16.
The trophic ecology of Octopus vulgaris paralarvae collected in 2008 off the Ría de Vigo, NW Spain (42° 12.80′ N–9° 00.00′ W), was approached by both morphological
and molecular methods. External digestion of prey and posterior suction of the liquefied contents by wild O. vulgaris paralarvae made the morphological identification of gut contents impossible. Thus, a PCR-based method using group-specific
primers was selected to identify prey consumed by O. vulgaris paralarvae in the pelagic realm. The mitochondrial ribosomal 16S gene region was chosen for designing group-specific primers,
which targeted a broad range of crustaceans and fishes but avoided the amplification of predator DNA. These primers successfully
amplified DNA of prey by using a semi-nested PCR-based approach and posterior cloning. Homology search and phylogenetic analysis
were then conducted with the 20 different operational taxonomic units obtained to identify the putative organisms ingested.
The phylogenetic analysis clustered ingested prey into 12 families of crustaceans (11 belonging to the order Decapoda and
1 to the order Euphausiacea) and two families of fishes (Gobiidae and Carangidae). According to the Czekanowski’s Index (CI),
the trophic niche breadth of O. vulgaris paralarvae is low (CI = 0.13), which means that these paralarvae are specialist predators at least during the first weeks
of their life cycle. It is the first time that natural prey has been identified in O. vulgaris paralarvae collected from the wild, and such knowledge may be critical to increasing the survival of O. vulgaris hatchlings in captivity, a goal that has been actively pursued since the 1960s by aquaculture researchers. 相似文献
17.
Using a turtle-borne camera system, changing flipper beat frequency and amplitude were measured in five diving green turtles
(Chelonia mydas Linnaeus 1758) in the Bahía de los Angeles, Mexico (28°58′N, 113°33′W). These observations were made between June and August
2002. Turtles worked hardest (i.e., had the highest flipper beat frequency and amplitude) at the start of descents when positive
buoyancy is predicted to oppose their forward motion. During the later part of descents, turtles worked less hard in line
with opposing buoyancy forces being reduced. For example, flipper beat frequency declined from about 60–80 beats min−1 at the start of descent to around 25–40 beats min−1 after 30 s of the descent. At the start of ascents the flipper beat frequency was around 30 beats min−1, lower than on descent, and declined as the ascent progressed with often passive gliding for the final few meters to the
surface. This pattern of effort during diving appears to apply across a range of marine reptiles, birds and mammals suggesting
that graded effort during descent and ascent is an optimum solution to minimising the cost of transport during diving. 相似文献
18.
Hawksbill sea turtles (Eretmochelys imbricata) nesting in Barbados (Needham’s Point, 13° 04′ 41.33′′ N, 59° 36′ 32.69′′W) were outfitted with GPS dataloggers over three
breeding seasons (2008–2010) to track movement during inter-nesting intervals. Most females established spatially restricted
resident areas up current and within 7 km of the nesting beach where they spent the majority of the inter-nesting interval.
Females nesting earlier in the season settled on shallower sites. Only experienced remigrant turtles occupied the most distant
resident areas. Females tracked for multiple inter-nesting intervals exhibited site fidelity, but the area contracted and
the activity of females decreased with each successive interval. Hawksbills may trade off site characteristics with distance
from the nesting beach and reduce activity over the course of the breeding season to optimise energy reserves during inter-nesting
intervals. 相似文献
19.
The horizontal and vertical distributions of adult mesopelagic fishes are described from acoustic and trawl surveys over the full-depth of 500 m at 169 stations on a longitudinal transect crossing the Humboldt Current (03°45′S, 81°76′W and 18°23′S, 71°13′W) at 50–200 nautical miles off Peru during austral spring (October–November) of 2001, 2002 and 2003. A total of 2,952 kg of fishes was collected, which included 13 families, 23 genera and 28 species. The mesopelagic community is dominated by the families Phosichthyidae (Vinciguerria lucetia), Myctophidae (Diogenichthys laternatus and Lampanyctus idostigma) and Bathylagidae (Leuroglossus urotranus), accounting for 60.4, 12.8 and 3.7%, respectively, of the total catch. Based on horizontal distribution patterns these species were categorized into three groups, i.e. northern-central upwelling front group (L. urotranus, Nemichthys fronto and Scopelarchoides nicholsi), Southern upwelling front group (Hygophum reinhardti, Myctophum nitidulum, Paralepis sp and Scopeloberyx sp.) and pan-Humboldt Current group (V. lucetia, D. laternatus, L.
(Nannobrachium)
idostigma, L. omostigma, M. aurolaternatum, Triphoturus oculeus, Bathylagus
(Melanolagus) berycoides, Leuroglossus stilbius, Argyropelecus affinis, Sternoptyx obscura, Melamphaes sp., Stomias sp. and Scopelosaurus sp.). Nighttime vertical distribution was characterized by a single abundance peak in the upper 50 m. Daytime patterns showed three peaks of abundance: an upper peak, in the upper 100 m, a midwater peak between 200 and 400 m, coinciding with an oxygen minimum zone, and a deeper peak between 400 and 500 m. V. lucetia was dominant in the upper and midwater peaks while myctophids, other planctivorous and piscivorous fishes were distributed in the midwater. Acoustic back-scattered energy (S
a) was ubiquitous in the region. Maximum S
a was mainly located between 11° and 18°S during day and night. V. lucetia is a significant component of the sound-scattering layers in the Humboldt Current Region off Peru. 相似文献
20.
The microbial community cultured from the marine sponge Rhopaloeides odorabile Thompson et al. is dominated by a single bacterium, designated strain NW001. Sequence analysis of 1212 bp of the16S rRNA
gene of strain NW001 indicates that it is a member of the α-subgroup of the class Proteobacteria. The association between
this bacterium and its host sponge was observed in healthy R. odorabile collected from six different reefs in the Great Barrier Reef representing a geographic distance of 460 km, and in four collections
in different seasons in 1997–1998 at Davies Reef (18°49.6′S; 147°34.49′E). The proportion of colonies of strain NW001 in samples
from R. odorabile, expressed as a percentage of the total heterotrophic bacterial colony count, showed no significant spatial (range: 81–98%)
or temporal differences (range: 81–99%), although colony counts of strain NW001 varied by up to two orders of magnitude between
reef sites and sampling periods. The location of strain NW001 within the sponge mesohyl was visualized by in situ hybridization,
using fluorescently labeled probes based on the 16S rRNA gene sequence of this strain. Cells of strain NW001 surround the
choanocyte chambers, suggesting that these bacteria may play a role in nutrient uptake by the sponge. The absence of strain
NW001 from corresponding seawater samples indicates that it has a specific, intimate relationship with R. odorabile and is not being utilized as a food source. A unique cyanobacterium related to the genera Leptolyngbya and Plectonema was also isolated from R. odorabile and characterized by 16S rRNA gene sequencing.
Received: 19 May 2000 / Accepted: 18 November 2000 相似文献