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1.
We compared, through allozyme and cytochrome b sequence analyses, populations of Bathygobius soporator from four localities on the Brazilian coast with those from the Oceanic Islands of the Rocas Atoll (230 km off the Brazilian coast) and the Bahamas (5700 km northwest from Rocas). The population from the Rocas Atoll was genetically more similar to the geographically distant Bahamas (gene identity, I=0.92) than to the supposedly conspecific populations from the Brazilian coast (I<0.55). Five diagnostic allozyme loci and a high level of nucleotide divergence (Kimura 2-parameters=0.21) were found between the two groups, further confirming that they must belong to different biological species. Since the type locality of B. soporator is in the Caribbean, the binomial should be maintained for the Bahamas/Rocas Atoll populations, and the other Brazilian populations of Bathygobius analysed either represent the occurrence of a species of Bathygobius hitherto not cited for the Brazilian coast, or belong to a new species. The coastal populations of this species were also found to be highly structured (FST=0.18; p<0.05), indicating that, even along the coast, levels of gene flow of this species are limited. This could be related to their reproductive biology (adhesive benthic eggs with parental care and short length of larval life). The timings of the divergence between the Caribbean and the Southwest Atlantic species found here, estimated from allozymes and cytb sequences, are very similar (around 10 MY bp), and correlate with the start of the Amazon river outflow. The colonization of the Rocas Atoll by populations from the Caribbean seems to have taken place after the Caribbean and the Brazilian coast species had diverged.  相似文献   

2.
Synopsis Sampling in six estuaries of the east coast of James and Hudson Bays between 1973 and 1977 has revealed latitudinal differences in the composition of fish communities. Arctic and subarctic marine species are more prominent in estuaries of Hudson Bay. Fewer species are found northwards with 35 species in lower rivers and estuaries of James Bay and only 24 in those of Hudson Bay, for a total of 38 species. Climate, postglacial dispersion and restricted space are proposed as causes of the observed distribution of fishes. Send reprint request to this address  相似文献   

3.
The Indo-Pacific mud sleeper Butis koilomatodon (Eleotridae) is recorded for the first time in the south-western Atlantic Ocean, based on 23 specimens caught at seven localities along the northern, north-eastern, eastern and south-eastern Brazilian coast. The occurrence of males and females in different ontogenetic stages indicates that this exotic mud sleeper breeds there. This invasive species has the potential to compete for food and microhabitat with several native gobies and an endemic blenny that dwell in estuaries and mangroves, besides preying on native fishes and crustaceans.  相似文献   

4.
Fishermen’s local knowledge of fishing resources may be an important source of information to improve artisanal tropical fisheries management, such as those found in Brazil, where most data on fish biology is lacking. We aim to study the local ecological knowledge that Brazilian coastal fishers have about reproductive aspects (season, places and migration) of 13 coastal fish species of commercial importance. We selected fishermen with more than 30 years of fishing practice and we interviewed a total of 67 fishermen: 29 from the southeastern coast, from the communities of Puruba, Almada, Picinguaba and Bertioga, and 38 from the northeastern coast, from the communities of Valença, Arembepe and Porto Sauípe. In the interviews, we used standardized questionnaires and showed photos of fish species. Our results indicate some general patterns in fishes’ reproduction according to fishermen knowledge: fish species spawn in open ocean, near reefs or in coastal rivers (estuaries); some fishes reproduce during the summer and others in winter, while some have more defined spawning months. The main fish migratory patterns mentioned by interviewees were: long migrations along the coast, usually in the South to North direction, short migrations among reefs, fishes that do not migrate, migrations between the shore and open ocean and migrations between the sea and coastal rivers. Fishermen’s knowledge differed among fish species: most fishermen did not know spawning places or seasons of large pelagic fishes, which raised concerns of their possible depletion. We compared such ethnoichthyological information with available scientific data, indicating promising insights about reproduction and migration of Brazilian coastal fishes. Data gathered from local fishermen may provide inexpensive and prompt information, potentially applicable to fisheries management. Our approach might be useful to several other small-scale fisheries, especially the tropical ones, where there is a high diversity of target species and a low biological and ecological knowledge about these species.  相似文献   

5.
In this study, we present the first data about putative source populations of the vagrant Subantarctic fur seal, Arctocephalus tropicalis, found on the Brazilian coast, through the comparison of their mitochondrial DNA control sequences to exclusive haplotypes from the main breeding colonies of the species. The results indicated that, despite the majority of the vagrant individuals are from Gough Island (the closest breeding site to the Brazilian coast), they also come from other reproductive colonies, such as Crozet Island, a distance around 16,500 km from the Brazilian coast. Furthermore, the molecular data identified three possible management units: (1) Gough, (2) Amsterdam, and (3) Marion, Macquarie and Crozet. This significant genetic subdivision must be taken into account in any future management plan for the species conservation, including rehabilitation and even reintroduction of vagrant fur seals. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

6.
Dusky grouper (garoupa, Epinephelus marginatus) is an important catch for several artisanal small-scale fisheries along the Brazilian coast. It is a sedentary, monandric, and late maturing protogynous species, which makes it vulnerable to overharvesting even though it is mainly caught through hook and line or spear fishing through free diving. Lack of information on the ecology and biology of this species in Brazil is astonishing. Much of the information found in the literature concerns Mediterranean dusky groupers. Studies compiling local knowledge (ethnoecology) about fish species complement biological data, and have been fundamental for effective fisheries management. In this study, our objectives are to obtain data about dusky grouper through fish catches and analysis of stomach contents and gonad maturation (macroscopic analyses), along with interviews from fishermen from six small-scales communities from the southern (Pântano do Sul, Florianópolis, Santa Catarina State) to the northern Brazilian coast (Porto Sauípe, Bahia State). We conclude that precautionary approaches and 'data-less' management approaches are needed in the coast of Brazil. Research on this species and on the potential of aquaculture for its cultivation, are urgent, due to the apparent vulnerability and decrease of dusky grouper along the coast of Brazil.  相似文献   

7.
Trypauchen vagina (Bloch & Schneider, 1801) is a goby that lives burrowed into the substrata feeding on small invertebrates. It is native to the Indo-pacific region, ranging from Kuwait to China. Recently, this fish has been reported outside the original range of distribution, being found in the Mediterranean Sea, and more recently in the northeastern Brazilian coast. The Mediterranean reports are usually associated with Lessepsian migration, while the reports from Brazil are possibly related to ballast water transportation. In the present work, we provide eight new records from southeastern Brazilian coast, all made in São Paulo state, far from the first record. These additional records raised concern since the presence of an alien species could implicate in environmental and economic losses. Thus, we decide to model the environmental suitability for this goby in the Brazilian coast, specially focusing on major ports, usually places with high ballast water propagule pressure. In addition, an analysis of the suitability in the Red Sea was also made, to verify the hypothesis of Lessepsian migration. The results revealed that temperature and primary productivity are among the most important parameters for the presence of T. vagina, also indicating a high environmental suitability for this species in the Red Sea and Brazilian coast, especially in southeastern region, where the new records were made. Due to the number of collected individuals, it is hard to affirm that this taxon presents a self-sustaining population in Brazilian waters, but the several registers, in different locations and different life stages point to an establishment of the species in this new region. This population status allied with a high environmental suitability is alarming and should motivate new studies concerning T. vagina in Brazilian waters.  相似文献   

8.
The Paiva's blenny Lupinoblennius paivai is redescribed and its range redefined along the Brazilian coast. It differs from its congeners by the presence of three cephalic pores between the dorsal‐fin base and lateral line, dorsal‐fin elements XII, 12, anal‐fin elements II, 16, pectoral‐fin rays 14 and 10 + 20 vertebrae. It is here reported from Amazon estuaries (Marajó and Mosqueiro islands, Pará State), increasing its range by c. 3000 km. Lupinoblennius paivai is one of the few blenniid species able to tolerate low salinities. New data about its meristics and morphometrics are presented, as well as a new habitat type.  相似文献   

9.
A key step in identifying global change impacts on species and ecosystems is to quantify effects of multiple stressors. To date, the science of global change has been dominated by regional field studies, experimental manipulation, meta‐analyses, conceptual models, reviews, and studies focusing on a single stressor or species over broad spatial and temporal scales. Here, we provide one of the first studies for coastal systems examining multiple stressor effects across broad scales, focused on the nursery function of 20 estuaries spanning 1,600 km of coastline, 25 years of monitoring, and seven fish and invertebrate species along the northeast Pacific coast. We hypothesized those species most estuarine dependent and negatively impacted by human activities would have lower presence and abundances in estuaries with greater anthropogenic land cover, pollution, and water flow stress. We found significant negative relationships between juveniles of two of seven species (Chinook salmon and English sole) and estuarine stressors. Chinook salmon were less likely to occur and were less abundant in estuaries with greater pollution stress. They were also less abundant in estuaries with greater flow stress, although this relationship was marginally insignificant. English sole were less abundant in estuaries with greater land cover stress. Together, we provide new empirical evidence that effects of stressors on two fish species culminate in detectable trends along the northeast Pacific coast, elevating the need for protection from pollution, land cover, and flow stressors to their habitats. Lack of response among the other five species could be related to differing resistance to specific stressors, type and precision of the stressor metrics, and limitations in catch data across estuaries and habitats. Acquiring improved measurements of impacts to species will guide future management actions, and help predict how estuarine nursery functions can be optimized given anthropogenic stressors and climate change scenarios.  相似文献   

10.
Environmental conditions in salt marsh creeks are intermediate between the open tidal coast and estuaries. A large salt marsh creek at the island of Sylt (North Sea) was studied in order to test whether its fauna is more similar to that of the open tidal coast or to that of estuaries. Because of a sandy bar at the seaward opening, the tidal range is only 10 cm in the creek, and the water level never drops below the level of the sand bar. Zoobenthos in the sandy bottom and on the sandy shores was studied at both ends and in the middle of the creek. Polychaeta and Plathelminthes were determined to species level. On an average, 2115 metazoans were found below 10 cm2 of surface area. At the seaward end of the creek, abundance and taxonomic composition are similar to that of the adjoining Wadden area. Nematoda are the dominant taxon, followed by Copepoda, Plathelminthes and Oligochaeta. Taxonomic composition is different at the landward end. Plathelminthes and Nematoda are most abundant followed by Copepoda. Both Oligochaeta and Polychaeta are scarce at these newly eroded sites. Plathelminth abundance at the landward end of the creek is exceptionally high (770–935·10 cm−2). Contrary to what is generally found in estuaries, the species density of Plathelminthes shows a significant increase toward the land. The species composition of Polychaeta and Plathelminthes indicates that the sites below mean high tide level of the creek correspond to the adjacent eulittoral Wadden area while the fauna of the supralittoral sites of the creek is similar to the fauna of supralittoral tidal coasts. Typical sublittoral species did not occur in the salt marsh creek. Thus, salt marsh creeks may be regarded as a small-scale model for the tidal coast. In context with the results obtained, the definition of estuaries is discussed.  相似文献   

11.
The distributions of eight out of nine common species of waders (Charadrii) overwintering on UK estuaries have changed in association with recent climate change. These birds represent a high proportion of various populations from breeding grounds as far apart as Greenland to the west to high‐arctic Russia to the east. During warmer winters, smaller proportions of seven species wintered in south‐west Britain. The distributions of the smaller species show the greatest temperature dependence. The opposite was found for the largest species and no relationship was found for a particularly site‐faithful species. In north‐west Europe, the winter isotherms have a broadly north to south alignment, with the east being colder than the west. The average minimum winter temperatures across the UK having increased by about 1.5°C since the mid‐1980s, the temperatures on the east coast during recent winters have been similar to those of the west coast during the mid‐1980s. On average, estuaries on the east and south coasts of Britain have muddier sediments than those on the west coast and thus support a higher biomass of the invertebrate prey of waders. We suggest that, with global climatic change, the advantage gained by waders wintering in the milder west to avoid cold weather‐induced mortality is diminished. Consequently, more choose to winter in the east and thus benefit from better foraging opportunities. The implications of these results are considered in terms of a site‐based approach to wildlife protection used in Europe and elsewhere.  相似文献   

12.
13.
The distribution of macroinvertebrates and fishes in Tasmanian estuaries   总被引:4,自引:0,他引:4  
The distributions of 390 taxa of benthic macroinvertebrates collected in forty-eight estuaries and 101 fish species collected in seventy-five Tasmanian estuaries were related to geographical and environmental variables. Distribution patterns for the two taxonomic groups were largely congruent at both between and within-estuary scales. Faunal composition and the number of species collected at a site were primarily related to site salinity, the biomass of seagrass and tidal range. At the broader estuary scale, the distributions of macroinvertebrate and fish assemblages were primarily correlated with the presence of an entrance bar. Species richness varied with geographical location for both macrofauna and fishes, with highest numbers of species occurring in the Furneaux Group, north-eastern Tasmania and south-eastern Tasmania. These patterns primarily reflected differences in estuary type between regions rather than concentrations of locally endemic species. Although the majority of species collected during the study were marine vagrants, they constituted a very low proportion of total animal densities within estuaries. Only four species considered exotic to Tasmania were identifed. Nearly all species recorded from Tasmanian estuaries occurred widely within the state and have also been recorded in south-eastern Australia. Only 1% of estuarine fish species and < 5% of invertebrate species were considered endemic to the state. The generally wide ranges of species around Tasmania were complicated by (i) the absence of most species from the west coast (ii) a small (< 10%) component of species that occurred only in the north-east and Furneaux Group (eastern Bass Strait), and (iii) a few species (< 5%) restricted to other regions. The low number of species recorded from estuaries along the western Tasmanian coast reflected extremely low faunal biomass in that area. This depression in biomass on the west coast was attributed to unusually low concentrations of dissolved nutrients in rivers and dark tannin-stained waters which greatly restricted algal photosynthesis and primary production.  相似文献   

14.
An updated molecular phylogeny of the blenny genus Ophioblennius, with a focus on two geographically disjunct morphotypes observed in Brazil, is presented. The analyses showed that specimens from the north‐eastern Brazilian coast are the endemic redlip blenny Ophioblennius trinitatis, but specimens from the southern Brazilian coast are conspecific to an undescribed east Atlantic Ocean (Gulf of Guinea) species, previously unknown in Brazil. Possible explanations for this geographical pattern include: natural larval dispersal and rafting across the Atlantic; an unknown ecological attribute that enabled this species to colonize southern Brazil; oil platforms as introduction vectors.  相似文献   

15.
The northernmost occurrence of Bassanago albescens in the western Atlantic Ocean (off the coast of Rio de Janeiro, Brazil) is presented and compared with the available data on this species. Specimens formerly identified as Rhynchoconger guppyi from off the southern Brazilian coast are regarded as B. albescens.  相似文献   

16.
Brazilian endemic batoid elasmobranch populations have declined dramatically in the past 40 years due to anthropic activities (e.g., overfishing). The Brazilian guitarfish, Pseudobatos horkelii, included in the IUCN red list of endangered species [Critically Endangered (CR)], has been captured as by-catch by trawling fishing boats to the edge of extinction. Despite governmental conservation initiatives, the species is still caught and commercialized along the Brazilian coast. In this study, the authors report three rare aggregation events for the Brazilian coast of P. horkelii, inside the only nearshore no-entry Brazilian marine protected area. Strategies for its protection are also discussed.  相似文献   

17.
A rich and apparently undisturbed fish community (132 species from 52 families) is found in the Parcel Manuel Luiz Marine State Park, Brazil. Comparisons with data obtained in other sites in Brazil and the Caribbean, using the same visual census technique, demonstrate high variation in community structure. The absence of some species found along the Brazilian coast suggests an ecological barrier between the study area and the remaining coastline.  相似文献   

18.
Siderastrea stellata and S. radians are scleractinian coral species that present a remarkable overlap of diagnostic characteristics and sympatric distribution. Moreover, both are viviparous with similar reproductive strategies and with a gregarious larval behavior. Samples of both species from the Brazilian coast were analyzed using 18 isozymic loci to quantify their genetic variability and populational structure. Results confirmed species identity, high intrapopulational variability and revealed moderate genetic structuring among all samples (S. stellata: F (ST) = 0.070; S. radians: F (ST) = 0.092). Based on genotypic diversity analysis, there was evidence that local recruitment may have a minor role in the populations (mean, G ( o ):G ( e )= 1.00 +/- 0.0003 SD for S. stellata and 0.99 +/- 0.0023 SD for S. radians). Deviations towards heterozygote deficiencies found in both Siderastrea species could be explained by the Wahlund effect, since there was evidence that populations might be composed of colonies of different ages. In S. radians it is also likely that there is some inbreeding occurring in the studied populations. Despite the brooding pattern and the gregarious larval behavior, our data suggest the occurrence of gene flow along the Brazilian coast. This is the first study on population genetics of Brazilian reef corals.  相似文献   

19.
Ambassidae are represented in South African estuaries by three species which are very similar in external morphology, feeding ecology, alimentary system and distribution. The co-existence and spatial separation of these species of Ambassis in the estuaries of southern Africa can be explained by the tolerance of each to salinity and temperature. Investigations of the temperature tolerance ranges of the three species suggest that the osmoregulatory capability of Ambassis productus in reduced salinities (<10%) increases while that of A. gymnocephalus decreases sharply in salinities below 20%. A. natalensis , which is endemic to the south-east coast of Africa, is adapted to a wide range of estuarine conditions. Interaction between salinity and temperature tolerances on the limits within which Ambassis spp. survive is significant with regard to the distribution of the three species in estuaries. Catch data showed that A. productus is restricted to areas of low salinity and seasonal low temperature (upper reaches of estuaries), A. gynmocephalus to high salinities >25% (estuary mouths) and A. natalensis to intermediate salinities associated with the middle reaches of estuaries.  相似文献   

20.
Hesionides riegerorum n. sp. is a new freshwater polychaete species. It was found in considerable numbers in the interstitial habitat of sandy banks of the Chowan River in North Carolina, USA. There are no general differences in the organization and behavior compared to the marine species of this genus. The new species, however, is unequivocally distinguished from them by slight quantitative differences and more striking qualitative features. The localities not far from the coast point to an immigration path for this freshwater polychaete that has been shown also for most of the other marine interstitial immigrants: directly from sandy intertidal beaches along brackish estuaries into the limnopsammal.  相似文献   

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