Massa corporal e morfometria de Conopophaga melanops (Aves: Conopophagidae): uma compara����o intrasexual e entre ��reas continental e insular de Mata Atl��ntica, na regi��o da Ba��a da Ilha Grande, RJ

A forma e o tamanho de um determinado organismo devem caracterizar aspectos ecol��gicos, uma vez que a morfometria �� resultado da evolu����o. Diferen��as nos caracteres morfol��gicos podem ter sido causadas por isolamento geogr��fico, mesmo em per��odos de tempo relativamente curtos. O estudo da morfologia ecol��gica �� uma tentativa de compreender a rela����o funcional entre varia����o morfol��gica e a ecologia dos animais. A varia����o nos atributos morfom��tricos de tamanho corp��reo entre os sexos pode ser um resultado da a����o da sele����o sexual. O presente estudo aborda uma compara����o intrasexual e entre ��rea continental e insular da morfologia de Conopophaga melanops (Vieillot, 1818), tendo sido realizado em uma ��rea na Ilha Grande e em outra ��rea na Reserva Ecol��gica Rio das Pedras (ReRP), RJ. A esp��cie, end��mica de Mata Atl��ntica e estritamente florestal, apresenta dimorfismo sexual, contudo indiv��duos jovens possuem plumagem similar a de f��meas. As aves foram capturadas com redes neblina, e doze medidas morfom��tricas foram obtidas de 51 indiv��duos. A confirma����o do sexo foi realizada por m��todos moleculares baseados no DNA em 69 amostras. O percentual de erro na identifica����o do sexo em campo, pela plumagem, foi de 9,7%. A confirma����o molecular do sexo �� uma importante ferramenta que t��m potencial de revelar padr��es demogr��ficos em estudos comportamentais e reprodutivos desta esp��cie. Na ReRP o comprimento da asa e a vari��vel dist��ncia da cabe��a at�� a ponta do bico apresentaram uma diferen��a significativa, sendo maior para machos do que para f��meas. J�� na Ilha Grande, as ��nicas vari��veis que apresentaram diferen��a significativa foram comprimento da cauda (maior em machos) e altura do bico na base (maior em f��meas). As diferen��as de tamanho da asa entre os sexos corroboram com padr��es de diversas outras esp��cies Neotropicais. A diferen��a morfom��trica do bico pode estar associada �� ecologia alimentar desta esp��cie. Tanto f��meas quanto machos foram maiores na ilha do que no continente com rela����o ao comprimento total e comprimento da asa, al��m de comprimento da cauda maior para os machos.

Effects of rapid decompression and exposure to bright light on visual function in black rockfish (Sebastes melanops) and Pacific halibut (Hippoglossus stenolepis)

Demersal fishes hauled up from depth experience rapid decompression. In physoclists, this can cause overexpansion of the swim bladder and resultant injuries to multiple organs (barotrauma), including severe exophthalmia (���pop-eye���). Before release, fishes can also be subjected to asphyxia and exposure to direct sunlight. Little is known, however, about possible sensory deficits resulting from the events accompanying capture. To address this issue, electroretinography was used to measure the changes in retinal light sensitivity, flicker fusion frequency, and spectral sensitivity in black rockfish (Sebastes melanops) subjected to rapid decompression (from 4 atmospheres absolute [ATA] to 1 ATA) and Pacific halibut (Hippoglossus stenolepis) exposed to 15 minutes of simulated sunlight. Rapid decompression had no measurable influence on retinal function in black rockfish. In contrast, exposure to bright light significantly reduced retinal light sensitivity of Pacific halibut, predominately by affecting the photopigment which absorbs the green wavelengths of light (���520���580 nm) most strongly. This detriment is likely to have severe consequences for postrelease foraging success in green-wavelength-dominated coastal waters. The visual system of Pacific halibut has characteristics typical of species adapted to low light environments, and these characteristics may underlie their vulnerability to injury from exposure to bright light.

Preliminary use of oxygen stable isotopes and the 1983 El Ni��o to assess the accuracy of aging black rockfish (Sebastes melanops)

Black rockfish (Sebastes melanops) range from California to Alaska and are found in both nearshore and shallow continental shelf waters (Love et al., 2002). Juveniles and subadults inhabit shallow water, moving deeper as they grow. Generally, adults are found at depths shallower than 55 meters and reportedly live up to 50 years. The species is currently managed by using information from an age-structured stock assessment model (Ralston and Dick, 2003).

Maturity, ovarian cycle, fecundity, and age-specific parturition of black rockfish (Sebastes melanops)

From 1995 to 1998, we collected female black rockfish (Sebastes melanops) off Oregon in order to describe their basic reproductive life history and determine age-specific fecundity and temporal patterns in parturition. Female black rockfish had a 50% probability of being mature at 394 mm fork length and 7.5 years-of-age. The proportion of mature fish age 10 or older significantly decreased each year of this study, from 0.511 in 1996 to 0.145 in 1998. Parturition occurred between mid-January and mid-March, and peaked in February. We observed a trend of older females extruding larvae earlier in the spawning season and of younger fish primarily responsible for larval production during the later part of the season. There were differences in absolute fecundity at age between female black rockfish with prefertilization oocytes and female black rockfish with fertilized eggs; fertilized-egg fecundity estimates were considered superior. The likelihood of yolked oocytes reaching the developing embryo stage increased with maternal age. Absolute fecundity estimates (based on fertilized eggs) ranged from 299,302 embryos for a 6-year-old female to 948,152 embryos for a 16-year-old female. Relative fecundity (based on fertilized eggs) increased with age from 374 eggs/g for fish age 6 to 549 eggs/g for fish age 16.

Sex ratio and morphological characteristics of Rufous Gnateaters, Conopophaga lineata (Aves, Passeriformes) in Atlantic forest fragments

Unequal sex ratios lead to the loss of genetic variability, decreasing the viability of populations in the long term. Anthropogenic activities often disturb the natural habitats and can cause alterations in sex ratio and morphological characteristics of several species. Forest fragmentation is a major conservation concern, so that understanding its effects in natural populations is essential. In this study, we evaluated the sex ratio and the morphological characteristics of Rufous Gnateaters (Conopophaga lineata (Wied, 1831)) in small and large forest fragments in Minas Gerais, Brazil. Birds (n = 89) were sexed by plumage characteristics and molecular markers. The molecular analysis showed that plumage is not a totally reliable method for sexing Rufous Gnateaters. We observed that sex ratio did not differ between large and small forest fragments, but birds in small fragments had larger wings and tarsus. Wing and tarsus changes may affect the movement ability of individuals within and among forest fragments. In conclusion, Rufous Gnateaters have been able to survive in both small and large Atlantic rain forest fragments without altering their sex ratio, but morphological changes can be prejudicial to their long term survival.

Contemporary genetic, historical genetic and morphological data sets for the Yellow-tufted Honeyeater Lichenostomus melanops

Understanding the evolutionary history of threatened populations can improve their conservation management. Re-establishment of past but recent gene flow could re-invigorate threatened populations and replenish genetic diversity, necessary for population persistence. One of the four nominal subspecies of the common yellow-tufted honeyeater, Lichenostomus melanops cassidix, is critically endangered despite substantial conservation efforts over 55 years. Using a combination of morphometric, genetic and modelling approaches we tested for its evolutionary distinctiveness and conservation merit. We confirmed that cassidix has at least one morphometric distinction. It also differs genetically from the other subspecies in allele frequencies but not phylogenetically, implying that its evolution was recent. Modelling historical distribution supported the lack of vicariance and suggested a possibility of gene flow among subspecies at least since the late Pleistocene. Multi-locus coalescent analyses indicated that cassidix diverged from its common ancestor with neighbouring subspecies gippslandicus sometime from the mid-Pleistocene to the Holocene, and that it has the smallest historical effective population size of all subspecies. It appears that cassidix diverged from its ancestor with gippslandicus through a combination of drift and local selection. From patterns of genetic subdivision on two spatial scales and morphological variation we concluded that cassidix, gippslandicus and (melanops + meltoni) are diagnosable as subspecies. Low genetic diversity and effective population size of cassidix may translate to low genetic fitness and evolutionary potential, thus managed gene flow from gippslandicus is recommended for its recovery.

Accounting for management costs in sensitivity analyses of matrix population models

Traditional sensitivity and elasticity analyses of matrix population models have been used to inform management decisions, but they ignore the economic costs of manipulating vital rates. For example, the growth rate of a population is often most sensitive to changes in adult survival rate, but this does not mean that increasing that rate is the best option for managing the population because it may be much more expensive than other options. To explore how managers should optimize their manipulation of vital rates, we incorporated the cost of changing those rates into matrix population models. We derived analytic expressions for locations in parameter space where managers should shift between management of fecundity and survival, for the balance between fecundity and survival management at those boundaries, and for the allocation of management resources to sustain that optimal balance. For simple matrices, the optimal budget allocation can often be expressed as simple functions of vital rates and the relative costs of changing them. We applied our method to management of the Helmeted Honeyeater (Lichenostomus melanops cassidix; an endangered Australian bird) and the koala (Phascolarctos cinereus) as examples. Our method showed that cost-efficient management of the Helmeted Honeyeater should focus on increasing fecundity via nest protection, whereas optimal koala management should focus on manipulating both fecundity and survival simultaneously. These findings are contrary to the cost-negligent recommendations of elasticity analysis, which would suggest focusing on managing survival in both cases. A further investigation of Helmeted Honeyeater management options, based on an individual-based model incorporating density dependence, spatial structure, and environmental stochasticity, confirmed that fecundity management was the most cost-effective strategy. Our results demonstrate that decisions that ignore economic factors will reduce management efficiency. ��2006 Society for Conservation Biology.

Food habits as an ecological partitioning mechanism in the nearshore rockfishes (Sebastes) of Carmel Bay, California

In the kelp forests of Carmel Bay there are six common rockfishes (Sebastes). Three are pelagic (S. serranoides, S. mystinus, and S. melanops) and two are demersal (S. chrysomelas and S. carnatus). The sixth (S. atrovirens) is generally found a few meters above the sea floor. The pelagic rockfishes which are spatially overlapping have different feeding habits. All rockfishes except S. mystinus utilize juvenile rockfishes as their primary food source during the upwelling season. Throughout the non-upwelling season, most species consume invertebrate prey. The pelagic rockfishes have shorter maxillary bones and longer gill rakers than their demersal congeners, both specializations for taking smaller prey. They also have longer intestines, enabling them to utilize less digestable foods. S. mystinus, which has the longest intestine, may be able to use algae as a food source. Fat reserves are accumulated from July through October, when prey is most abundant. Fat is depleted throughout the rest of the year as food becomes scarce and development of sexual organs takes place. Gonad development occurs from November through February for all species except S. atrovirens.

Genetic and morphological identification of pelagic juvenile rockfish collected from the Gulf of Alaska

Pelagic juvenile rockfish (Sebastes spp.) collected in surveys designed to assess juvenile salmonids and other species in the Gulf of Alaska in 1998 and 2000���2003 provide an opportunity to document the occurrence of the pelagic juveniles of several species of rockfish. Often, species identification of rockfish is difficult or impossible at this stage of development (~20 to 60 mm), and few species indigenous to Alaska waters have been described. Use of mitochondrial DNA markers for rockfish species allowed unequivocal identification of ten species (S. aleutianus, S. alutus, S. borealis, S. entomelas, S. flavidus, S. melanops, S. pinniger, S. proriger, S. reedi, and S. ruberrimus) in subsamples from the collections. Other specimens were genetically assignable to groups of two or three species. Sebastes borealis, S. crameri, and S. reedi were identified using morphological data. Combining genetic and morphological data allowed successful resolution of the other species as S. emphaeus, probably S. ciliatus (although S. polyspinis cannot be totally ruled out), and S. polyspinis. Many specimens were initially morphologically indistinguishable from S. alutus, and several morphological groups included fish genetically identified as S. alutus. This paper details the characteristics of these pelagic juveniles to facilitate morphological identification of these species in future collections. (PDF file contains 32 pages.)

Food habits and dietary variability of pelagic nekton off Oregon and Washington, 1979-1984

The food habits of 20 species of pelagic nekton were investigated from collections made with small-mesh purse seines from 1979-84 off Washington and Oregon. Four species (spiny dogfish, Squalus acanthias; soupfin shark, Galeorhinus zyopterus; blue shark, Prionace glauca; and cutthroat trout, Salmo clarki) were mainly piscivorous. Six species (coho salmon, Oncorhynchus kisutch; chinook salmon, O. tshawytscha; black rockfish, Sebastes melanops; yellowtail rockfish, S. f1avidus; sablefish, Anoplopoma fimbria; and jack mackerel, Trachurus symmetricus) consumed both nektonic and planktonic organisms. The remaining species (market squid, Loligo opalescens; American shad, Alosa sapidissima; Pacific herring, Clupea harengus pallasi; northern anchovy, Engraulis mordax; pink salmon, O. gorbuscha; surf smelt, Hypomesus pretiosus; Pacific hake, Merluccius productus; Pacific saury, Cololabis saira; Pacific mackerel, Scomber japonicus; and medusafish, Icichthys lockingtom) were primarily planktonic feeders. There were substantial interannual, seasonal, and geographic variations in the diets of several species due primarily to changes in prey availability. Juvenile salmonids were not commonly consumed by this assemblage of fishes (PDF file contains 36 pages.)

Relationship between abundance of juvenile rockfishes (Sebastes spp.) and environmental variables documented off northern California and potential mechanisms for the covariation

We estimated annual abundance of juvenile blue (Sebastes mystinus), yellowtail (S. f lavidus), and black (S. melanops) rockfish off northern California over 21 years and evaluated the relationship of abundance to oceanographic variables (sea level anomaly, nearshore temperature, and offshore Ekman transport). Although mean annual abundance was highly variable (0.01���181 fish/minute), trends were similar for the three species. Sea level anomaly and nearshore temperature had the strongest relationship with interannual variation in rockfish abundance, and offshore Ekman transport did not correlate with abundance. Oceanographic events occurring in February and March (i.e., during the larval stage) had the strongest relationship with juvenile abundance, which indicates that year-class strength is determined during the larval stage. Also of note, the annual abundance of juvenile yellowtail rockfish was positively correlated with year-class strength of adult yellowtail rockfish; this finding would indicate the importance of studying juvenile abundance surveys for management purposes.

Assembleia de aves consumidoras de frutos de sub-bosque em diferentes altitudes em uma ��rea de Mata Atl��ntica no estado do Rio de Janeiro

Neste estudo, investigamos a distribui����o altitudinal da composi����o, riqueza, abund��ncia das esp��cies de aves consumidoras de frutos em cinco altitudes e avaliamosa influ��ncia da estrutura da vegeta����o nas diversidades de aves. O estudo foi realizado na Reserva Ecol��gica de Guapia��u (REGUA) cont��gua ao Parque Estadual dos Tr��s Picos (PEPT), no munic��pio de Cachoeiras de Macacu, RJ. Coletamos os dados das aves em 24 excurs��es a campo, incluindo seis bimensais (jul./2010 a maio/2011) e 18 mensais (jul./2011 a dez./2012). Para amostragem das aves, utilizamos o m��todo de captura-marca����o-recaptura com redes de neblina, expostas durante sete h/dia em cinco altitudesao longo de uma varia����o altitudinal de 1000 m. O esfor��o amostral foi de 8400 h-rede. Para amostragem da estrutura da vegeta����o, sorteamos tr��s parcelas de 100 m2 adjacentes ��s linhas das redes em cada altitude, nas quais foram analisadas as densidades de diferentes h��bitos de vida. Das ��rvores, arvoretas e arbustos coletamos as medidas de altura total e di��metro da altura (no caso dos arbustos, o di��metro foi coletado a 50 cm do solo). Capturamos 448 indiv��duos correspondentes a 35 esp��cies de aves, distribu��das em 16 fam��lias. Destas, 26% s��o end��micas de Mata Atl��ntica, incluindo quatro esp��cies categorizadas com algum grau de vulnerabilidade. Dezesseis esp��cies foram classificadas como frug��voras enquanto 19 como inset��voras-frug��voras. Leptopogon amaurocephalus, Mionectes rufiventris, Lanio melanops, Chiroxiphia caudata foram capturadas nas cinco altitudes, sendo as ��ltimas duas esp��cies as mais abundantes. Registramos maior riqueza e abund��ncia de aves nas altitudes de 370 e 770 m. A composi����o de aves diferiu entre as altitudes, sendo 170 e 1000 m as mais dissimilares. As esp��cies de aves inset��voras-frug��voras predominaram nos sub-bosques das cinco altitudes. Registramos deslocamento altitudinal de cinco esp��cies de aves, sendo o maior deslocamento realizado por um indiv��duo de Attilarufus, capturado a 770 m e, recapturado a 370 m. Encontramos maior densidade de plantas no sub-bosque nas altitudes 170, 370 e 1000 m. Bambus foram registrados apenas a 1000 m, enquanto que as ervas foram limitadas ��s altitudes de 170 e 370 m. A estrutura da vegeta����o apresentou baixa similaridade entre as altitudes, principalmente devido a diferentes densidades das formas de vida e altura das plantas. Tr��s altitudes, 170, 370 e 1000 m, apresentaram alta densidade de indiv��duos no sub-bosque, sendo que esta ��ltima evidenciou uma estrutura da vegeta����o relativamente mais simples devido ao alto n��mero de ��rvores de baixa altura, ao maior n��mero de arvoretas e �� presen��a de bambus. A diversidade de aves foi sens��vel �� estrutura da vegeta����o, em especial �� altura das ��rvores que apresentou um decr��scimo da altura com o aumento da altitude. Esta rela����o entre a diversidade de aves e a estruturada da vegeta����o destaca a import��ncia da preserva����o da estrutura da vegeta����o para a manuten����o da diversidade de aves consumidoras de frutos da REGUA e do PETP

New insights into the diets of harbor seals (Phoca vitulina) in the Salish Sea revealed by analysis of fatty acid signatures

Harbor seals (Phoca fvitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available informationon harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.