共查询到20条相似文献,搜索用时 46 毫秒
1.
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
2.
Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel
(32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which
they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of
juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south
in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained
south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored
during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged
extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely
to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with
juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground. 相似文献
3.
C. J. Sears B. W. Bowen R. W. Chapman S. B. Galloway S. R. Hopkins-Murphy C. M. Woodley 《Marine Biology》1995,123(4):869-874
To determine the origin of juvenile loggerhead turtles (Caretta caretta) that occupy the Charleston Harbor Entrance Channel at Charleston, South Carolina, USA, mitochondrial DNA restriction-fragment length polymorphisms from this feeding population were compared to haplotypes from candidate nesting populations. Previous studies have defined two major nesting populations in the southeastern USA, one corresponding to Florida and the other to Georgia/South Carolina. These nesting populations are distinguished by both unique haplotypes and frequency distributions of common haplotypes. The frequency distribution of haplotypes in the juvenile feeding-ground population was significantly different from both nesting populations, implying that the feeding aggregate is drawn from two or more nesting populations. Assuming that these turtles are derived exclusively from rookeries in the southeastern USA, a maximum likelihood estimator indicates that approximately half are from the Florida rookery and half are from the northern (Georgia/South Carolina) rookery complex. Because 91% of nesting in the southeastern USA occurs in Florida rookeries and 8% in the northern complex, the 50:50 ratio indicates that juvenile turtles from Georgia and South Carolina tend to feed preferentially near their respective rookery locations. Human encroachment on this feeding habitat may pose an especially high risk to the smaller Georgia/South Carolina rookeries. 相似文献
4.
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
5.
J. Antonio Baeza 《Marine Biology》2008,153(3):387-395
A previous study predicted the evolution of monogamy in symbiotic crustaceans inhabiting scarce, relatively small hosts in
tropical environments where predation risk away from hosts is high. This prediction was tested in the shrimp Pontonia margarita, which inhabits the pearl oyster Pinctada mazatlanica. A total of 68 oysters were collected from the intertidal and shallow subtidal at two islands (Islas Secas [N 27° 55′, W
82° 03′] and Isla de La Coiba [N 27° 50′, W 97° 03′]) off the eastern tropical Pacific coast on 15 and 17 March 2007, respectively.
The population structure, distribution, male-female association pattern, and relative growth of the major claw and pleura
of the second abdominal segment of each shrimp retrieved were examined. Shrimps were found as heterosexual pairs in the mantle
cavity of hosts more frequently than would be expected by chance alone. Males occurred with females in the same host, independent
of the reproductive condition of the female or the stage of development of brooded embryos. This observation, and strong correlations
between the host and shrimp body size in both males and females suggest a long-term association between males and females
in each host. Sexual dimorphism in body size was minor, with males being just slightly smaller than females. In agreement
with predictions for monogamous species, the major claw of males did not display positive allometry, which has been generally
reported for polygamous shrimps. In turn, the pleura of the second abdomen presented negative allometry in males but positive
allometry in females. All available information suggests that Pontonia margarita has a socially monogamous mating system with males and females forming exclusive pairs in their hosts. 相似文献
6.
T. Knowles M. J. Leng M. Williams P. D. Taylor H. J. Sloane B. Okamura 《Marine Biology》2010,157(6):1171-1180
This is the first investigation of how two independent proxies for seawater temperature inference (zooid size variation and
oxygen isotope ratios of skeletal carbonate) relate to the actual measured ranges of temperature experienced by cheilostome
bryozoan colonies. Nine specimens of the bimineralic marine cheilostome bryozoan Pentapora foliacea (Ellis and Solander, 1786) were analysed, collected from ~18-m depth at two localities in Wales, UK—four from Skomer Island
(51°42′510″N, 5°13′42.60″W) and five from Porth Ysgaden, Lleyn Peninsula (52°54′6.75″N, 4°38′47.34″W). The annual range of
temperature implied by zooid size variability provides a good approximation of the actual range of temperature recorded by
a datalogger. However, annual ranges of temperature reconstructed from skeletal oxygen isotope ratios were narrower, typically
not showing the lowest temperatures experienced by the colonies. This can be explained by progressive thickening of zooid
skeletal walls during the life of the colony that homogenises the temperature signal by time-averaging over the lifetime of
the colonies. Our study provides evidence that a combined morphological isotope approach has great potential in the reconstruction
of annual ranges in seawater temperatures from historical and fossil bryozoans, particularly for species that lack ontogenetic
skeletal wall thickening and bimineralic skeletal composition. As cheilostome bryozoans have been common in benthic communities
since the Late Cretaceous, they represent a valuable and underutilised resource for the interpretation of environmental regimes. 相似文献
7.
Adults of motile intertidal invertebrates are able to seek shelter to avoid environmental stress associated with low tides,
but embryos within egg masses are effectively sessile for the duration of their encapsulation. Gastropod egg masses from 34
taxa on two rocky shores in SE Australia (34°37′08″S, 150°92′03″E and 34°35′45″S, 150°53′20″E) were surveyed over 2 years
(June 2002–May 2004) to test the hypothesis that eggs are deposited in patterns that minimize exposure to environmental stress.
Egg masses were expected to be predominantly deposited in shaded habitats not prone to environmental extremes. It was also
anticipated that the deposition of egg masses in habitats exposed to UVR, desiccation, and/or extremes in temperature would
occur when exposure to these abiotic factors was minimized. Among the taxa investigated, only four species spawned in full
sun (Bembicium nanum, Nerita morio, Siphonaria zelandica and S. denticulata). Summer had the highest UVR index, water temperature, and air temperature as well as the lowest daytime tides. Univariate
and multivariate analyses confirmed that egg mass abundance was highest during summer, with no change in egg mass size. This
study shows that those species depositing egg masses on the surfaces of rock platforms do not adjust the seasonal timing or
macrohabitat location of their spawning to avoid physiologically stressful conditions, particularly UVR. Alternate reasons
for the evolution of egg mass deposition behavior in apparently sub-optimal habitats are discussed, and it is almost certainly
the complex interplay of a variety of highly species-specific factors that is responsible for the patterns observed. 相似文献
8.
The quahog Mercenaria mercenaria has been introduced repeatedly to the Pacific coast of North America, but only one population is known to have become established.
In the 1970s, the population of M. mercenaria at Colorado Lagoon, in Los Angeles County, California (33o46′16″N, 118o08′05″W), was estimated at more than 300,000 individuals. To determine the current status of this non-indigenous species (NIS),
in 2009, we sampled 57 intertidal and 20 shallow subtidal plots, identifying and quantifying collected bivalves. No quahogs
were found among the 2,490 living bivalves in our plots, though two were found intertidally outside of our plots. The M. mercenaria population has thus collapsed since 1980, but the native community has not recovered. Six of the fourteen living bivalve
species we encountered were NIS; three are new records for the location, including the clam Venerupis philippinarum, which made up 87.6% of collected individuals. Though M. mercenaria is likely on its way to extinction on the US Pacific coast, the bivalve assemblage at this location remains heavily dominated
by NIS. 相似文献
9.
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
10.
Dana M. Bethea Loraine Hale John K. Carlson Enric Cortés Charles A. Manire James Gelsleichter 《Marine Biology》2007,152(5):1009-1020
To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (∼29°40′N, 85°13′W),
Tampa Bay near Anclote Key (∼28°10′N, 82°42.5′W), and Florida Bay (∼24°50′N, 80°48′W) from March through September, 1998–2000.
In each area, diet was assessed by life stage (young-of-the year, juveniles, and adults) and quantified using five indices:
percent by number (%N), percent by weight (%W), frequency of occurrence (%O), index of relative importance expressed on a
percent basis (%IRI), and %IRI based on diet category (%IRIDC). Diet could not be assessed for young-of-the-year in Tampa Bay or Florida Bay owing to low sample size. Diet analysis showed
an ontogenetic shift in northwest Florida. Young-of-the-year stomachs from northwest Florida (n = 68, 1 empty) contained a mix of seagrass and crustaceans while juvenile stomachs (n = 82, 0 empty) contained a mix of crabs and seagrass and adult stomachs (n = 39, 1 empty) contained almost exclusively crabs. Crabs made up the majority of both juvenile and adult diet in Tampa Bay
(n = 79, 2 empty, and n = 88, 1 empty, respectively). Juvenile stomachs from Florida Bay (n = 72, 0 empty) contained seagrass and a mix of crustaceans while adult stomachs contained more shrimp and cephalopods (n = 82, 3 empty). Diets in northwest Florida and Tampa Bay were similar. The diet in Florida Bay was different from those in
the other two areas, consisting of fewer crabs and more cephalopods and lobsters. Plant material was found in large quantities
in all stomachs examined from all locations (>15 %IRIDC in 6 of the 7 life stage-area combinations, >30 %IRIDC in 4 of the 7 combinations, and 62 %IRIDC in young-of-the-year diet in northwest Florida). Using species- and area-specific inputs, a bioenergetic model was constructed
to estimate daily ration. Models were constructed under two scenarios: assuming plant material was and was not part of the
diet. Overall, daily ration was significantly different by sex, life stage, and region. The bioenergetic model predicted increasing
daily ration with decreasing latitude and decreasing daily ration with ontogeny regardless of the inclusion or exclusion of
plant material. These results provide evidence that bonnetheads continuously exposed to warmer temperatures have elevated
metabolism and require additional energy consumption to maintain growth and reproduction.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
The ascidian Styela clava, native to the north-west Pacific, is an invasive species affecting New Zealand’s marine ecosystems, biodiversity and aquaculture
operations. To provide detailed information on the reproductive biology of S. clava in New Zealand for post-border biosecurity management, long-term seasonal patterns of gametogenesis were determined from
May 2006 to May 2008 in Auckland’s Waitemata Harbour (36°49′20″S, 174°45′85″E). Of particular interest was whether the critical
15°C threshold spawning temperature for reproduction observed in the Northern Hemisphere applied here to the first Southern
Hemisphere study. S. clava gametogenesis followed a regular seasonal cycle with ripe gametes appearing as early as September and persisting to June;
this time frame corresponds to the period when sea surface temperatures in the region first reach 15°C and with spawning occurring
mainly during late summer to early autumn. From photoperiod manipulation, it was determined that spawning occurred at approximately
18:20. The extended reproductive period and a short generation time in the Waitemata Harbour provides a lengthy opportunity
for S. clava to spread. Findings are discussed in relation to S. clava’s post-border management. 相似文献
12.
Genetic structure of summer flounder (Paralichthys dentatus) populations north and south of Cape Hatteras 总被引:1,自引:0,他引:1
Genetic divergence among samples of summer flounder (Paralichthys dentatus, Linnaeus) was estimated to evaluate the effect of Cape Hatteras, a well-known zoogeographic barrier in the western Atlantic
Ocean, on intraspecific gene flow. Previous studies based on meristic and morphometric variation and tagging data suggested
that gene flow might be limited among summer flounder populations north and south of Cape Hatteras, although the high vagility
of both juveniles and adults suggests otherwise. We analyzed genetic diversity revealed in the mitochondrial DNA (mtDNA) control
region in samples of juveniles and adults collected in 1992 to 1996 from coastal sites from Buzzard's Bay, Massachusetts to
Charleston, South Carolina. In contrast to previous morphological studies, analyses of mtDNA variation reveal no significant
population subdivision centered around Cape Hatteras.
Received: 17 September 1997 / Accepted: 8 September 1998 相似文献
13.
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
14.
The recovery of Ascophyllum nodosum, and the associated benthic community, was followed after repeated trampling disturbance at different intensities, from 2005
to 2010, at its southern limit (41°41′27″N; 8°50′57″W). The cover of A. nodosum and associated organisms and the demography of A. nodosum individuals in the most disturbed areas were followed over a recovery period of 54 months. Recovery of A. nodosum assemblages was negatively affected by increasing trampling intensity. After 54 months, the highest intensity plots were
still significantly different from control plots. Growth and mortality rates of A. nodosum increased shortly after disturbance but progressively recovered to levels close to control plots. The results of this study
demonstrate the sensitivity of this habitat-building species to human trampling and also show its plasticity to cope with
disturbance events. 相似文献
15.
The temperate sea anemone Anthopleura elegantissima is facultatively symbiotic with unicellular algae. Symbiotic A. elegantissima can supplement heterotrophic feeding with excess photosynthate from their algal partners, while asymbiotic individuals must
rely solely on heterotrophy. A. elegantissima individuals were collected from Swirl Rocks, Washington (48°25′6″ N, 122°50′58″ W) in July 2010, and prey capture and feeding
characteristics were measured to determine whether asymbiotic individuals are more efficient predators. Feeding abilities
were then measured again after a 3-week exposure to full sunlight or shaded conditions. Freshly collected asymbiotic anemones
had larger nematocysts, but symbiotic individuals showed greater nematocyte sensitivity. Sunlight enhanced digestion and reduced
cnida density in all anemones regardless of symbiotic state. Results suggest that the phototropic potential of A. elegantissima, as influenced by symbiotic condition, has little effect on heterotrophic capacity. The anemones appear to maximize heterotrophic
energy input independent of the presence or identity of their algal symbionts. 相似文献
16.
Giuseppe Guarnieri Antonio Terlizzi Stanislao Bevilacqua Simonetta Fraschetti 《Marine Biology》2012,159(5):1155-1164
Submarine caves are considered as a top priority for conservation, but the effects of common pressures are poorly known for
these habitats. Here, we examined the effect of recreational human visitation on a selection of submarine caves in a Mediterranean
Marine Protected Area (40°35′40″N; 8°11′39″E) where diving activities are regulated. Sampling was conducted in visited and
not visited caves to assess whether diving activities have a significant effect on cave habitats, what are the components
of biodiversity most affected by this disturbance, and its potential effects on spatial heterogeneity of benthic assemblages.
Results clearly showed that human visitation could significantly affect spatial patterns of benthic assemblages. Organisms
with erect growth forms were significantly more abundant and homogeneously distributed where diving activities are forbidden.
An increase in the small-scale heterogeneity of assemblages and a decrease in their three-dimensional structure could be the
ultimate consequences of human visitation. The interaction between specific stressors and the patterns of distribution of
species and assemblages can drive their spatial heterogeneity also in unique habitats like marine caves, representing an early
warning for the development of appropriate management measures. 相似文献
17.
Nicholas E. C. Fleming Jonathan D. R. Houghton Caroline L. Magill Chris Harrod 《Marine Biology》2011,158(9):2141-2146
Jellyfish are increasingly topical within studies of marine food webs. Stable isotope analysis represents a valuable technique
to unravel the complex trophic role of these long-overlooked species. In other taxa, sample preservation has been shown to
alter the isotopic values of species under consideration, potentially leading to misinterpretation of trophic ecology. To
identify potential preservation effects in jellyfish, we collected Aurelia aurita from Strangford Lough (54o22′44.73″N, 5o32′53.44″W) during May 2009 and processed them using three different methods prior to isotopic analysis (unpreserved, frozen
and preserved in ethanol). A distinct preservation effect was found on δ15N values: furthermore, preservation also influenced the positive allometric relationship between individual size and δ15N values. Conversely, δ13C values remained consistent between the three preservation methods, conflicting with previous findings for other invertebrate,
fish and mammalian species. These findings have implications for incorporation of jellyfish into marine food webs and remote
sampling regimes where preservation of samples is unavoidable. 相似文献
18.
Andrea Gori Sergio Rossi Cristina Linares Elisa Berganzo Covadonga Orejas Mark RT Dale Josep-Maria Gili 《Marine Biology》2011,158(8):1721-1732
In the Western Mediterranean Sea, the gorgonian Eunicella singularis (Esper, 1794) is found at high densities on sublittoral bottoms at depths from 10 to 70 m. Shallow colonies have symbiotic
zooxanthellae that deeper colonies lack. While knowledge of the ecology of the shallow populations has increased during the
last decades, there is almost no information on the ecology of the deep sublittoral populations. In October and November 2004
at Cap de Creus (42°19′12″ N; 03°19′34″ E), an analysis of video transects made by a remotely operated vehicle showed that
shallow populations (10–25 m depth) were dominated by small, non-reproductive colonies, while deep sublittoral populations
(50–67 m depth) were dominated by medium-sized colonies. Average and maximum colony heights were greater in the deeper populations,
with these deeper populations also forming larger patch sizes and more extensive regions of continuous substrate coverage.
These results suggest that shallow habitats are suitable for E. singularis, as shown by the high recruitment rate, but perturbations may limit or delay the development of these populations into a
mature stage. This contrasts with the deep sublittoral habitats where higher environmental stability may allow the development
of mature populations dominated by larger, sexually mature colonies. 相似文献
19.
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
20.
《Ecological modelling》2007,201(2):194-204
Age structure proportions (proportion of harvested individuals within each age class) are commonly used as support for regulatory restrictions and input for deer population models. Such use requires critical evaluation when harvest regulations force hunters to selectively harvest specific age classes, due to impact on the underlying population age structure. We used a stochastic population simulation model to evaluate the impact of using harvest proportions to evaluate changes in population age structure under a selective harvest management program at two scales. Using harvest proportions to parameterize the age-specific harvest segment of the model for the local scale showed that predictions of post-harvest age structure did not vary dependent upon whether selective harvest criteria were in use or not. At the county scale, yearling frequency in the post-harvest population increased, but model predictions indicated that post-harvest population size of 2.5 years old males would decline below levels found before implementation of the antler restriction, reducing the number of individuals recruited into older age classes. Across the range of age-specific harvest rates modeled, our simulation predicted that underestimation of age-specific harvest rates has considerable influence on predictions of post-harvest population age structure. We found that the consequence of uncertainty in harvest rates corresponds to uncertainty in predictions of residual population structure, and this correspondence is proportional to scale. Our simulations also indicate that regardless of use of harvest proportions or harvest rates, at either the local or county scale the modeled SHC had a high probability (>0.60 and >0.75, respectively) of eliminating recruitment into >2.5 years old age classes. Although frequently used to increase population age structure, our modeling indicated that selective harvest criteria can decrease or eliminate the number of white-tailed deer recruited into older age classes. Thus, we suggest that using harvest proportions for management planning and evaluation should be viewed with caution. In addition, we recommend that managers focus more attention on estimation of age-specific harvest rates, and modeling approaches which combine harvest rates with information from harvested individuals to further increase their ability to effectively manage deer populations under selective harvest programs. 相似文献