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Ecosystem effects of fishing in kelp forest communities 总被引：6，自引：0，他引：6
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M. Cristina Fossi Silvia Casini Letizia Marsili Stefania Ancora Gabriele Mori Giovanni Neri Antonella Ausili Teresa Romeo Alessandra Moscatelli Giuseppe Notarbartolo Di Sciara 《Marine Ecology》2002,23(S1):184-189
Abstract. Endocrine Disrupting Chemicals (EDCs) have the potential to alter hormone pathways that regulate reproductive processes in wildlife and fisheries. In this research the unexplored hypothesis that Mediterranean top predator species (such as large pelagic fish and marine mammals) are potentially at risk due to EDCs is investigated. In the Mediterranean environment, top predators accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, incurring high toxicological risk. Here we illustrate the need to develop sensitive biomarkers for evaluation of toxicological risk in top marine predators (Xiphias gladius, Thunnus thynnus thynnus) and non-lethal techniques, such as non-destructive biomarkers, for the hazard assessment of threatened species exposed to EDCs, such as marine mammals ( Stenella coeruleoalba, Tursiops truncatus, Delphinus delphis and Balaenoptera physalus ). 相似文献
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M. Flain 《新西兰海洋与淡水研究杂志》2013,47(1):21-24
The distribution of 376 salmon caught at sea between 41 °S and 46 °S up to 48 km off the east coast of the South Island between 1925 and 1978 is discussed. The distribution appears to be related to strong currents in Cook and Foveaux Straits, and to the Southland Current off the east coast of the South Island. Samples from the sea at Moeraki Peninsula had a higher incidence of stream‐reared fish and a lower mean fork length than samples from the Waitaki or Rakaia Rivers at spawning. 相似文献
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Jérôme Spitz Yves CherelStéphane Bertin Jeremy KiszkaAlexandre Dewez Vincent Ridoux 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(3):273-282
Long-finned pilot whales (Globicephala melas), Risso's dolphins (Grampus griseus), melon-headed whales (Peponocephala electra), Cuvier's beaked whales (Ziphius cavirostris), Sowerby's beaked whales (Mesoplodon bidens), northern bottlenose whales (Hyperoodon ampullatus), sperm whales (Physeter macrocephalus), dwarf sperm whales (Kogia sima) and pygmy sperm whales (Kogia breviceps) make up the large community of deep-diving odontocetes occurring off the Bay of Biscay, northeast Atlantic. The ecology of these toothed cetaceans is poorly documented worldwide. The present study described their prey preferences from stomach content analysis and showed resource partitioning within the assemblage. The majority of the species appeared to be mostly teutophageous. Fish was an important food source only for the Sowerby's beaked whale and, to a lesser extent, for the long-finned pilot whale. In terms of foraging habitats inferred from prey composition, either pelagic oceanic or demersal neritic habitats were exploited by toothed whales in the Bay of Biscay, with only the long-finned pilot whale foraging in the two habitats. Finally, with more than 14,000 identified cephalopods from 39 species, the present study highlighted also the poorly known deep-sea cephalopod community off the Bay of Biscay using top predators as biological samplers. 相似文献
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The biological oceanography of the East Australian Current and surrounding waters in relation to tuna and billfish catches off eastern Australia 总被引：1，自引：0，他引：1
J.W. Young A.J. HobdayR.A. Campbell R.J. KloserP.I. Bonham L.A. ClementsonM.J. Lansdell 《Deep Sea Research Part II: Topical Studies in Oceanography》2011,58(5):720-733
The surface and sub-surface biological oceanography of tuna fishing grounds within the East Australian Current (EAC) was compared in 2004 with two other fishing areas further offshore. Our aim was to determine whether the biological oceanography of the region could explain the distribution and intensity of pelagic fishery catches inside and outside the EAC at that time. The EAC fishing area was noticeably warmer, less saline and lower in nutrients than waters in the other fishing areas. The EAC waters were dominated by large diatoms, the biomass of which was significantly higher than in the seamount and offshore areas, apparently the result of a cold core eddy beneath the EAC surface filament. Over the seamount and offshore more typical Tasman Sea waters prevailed, although the presence of a relatively deeper oxygen minimum layer over the seamount suggested topographically induced mixing in the area. Notably, sub-surface zooplankton and micronekton biomass was significantly higher around the seamount than in the two other areas. The offshore region was characterised by frontal activity associated with the Tasman front. Micronekton net biomass was generally highest in surface waters in this region. Examination of tuna catch records at that time showed yellowfin tuna (Thunnus albacares) dominated the catches of the EAC, whereas swordfish (Xiphias gladius) and bigeye tuna (Thunnus obesus) were the main species caught offshore. We suggest the yellowfin tuna concentrate in waters that are not only warmer but where prey species are concentrated near the surface. Offshore, deeper living species such as swordfish and bigeye tuna (T. obesus) can take advantage of prey species that are distributed deeper in the water column and along the flanks of the many seamounts in the region, or that are concentrated at fronts associated with the Tasman Front. Although only a snapshot of the region, relatively consistent catch data over time suggests the underlying biological oceanography may persist over longer time periods, particularly during the Austral spring. 相似文献
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《African Journal of Marine Science》2013,35(2):413-421
The annual winter sardine run along the South African east coast impacts the KwaZulu-Natal (KZN) coastal system in a variety of ways. These include ecological impacts, such as enrichment of a largely oligotrophic environment, competition between migrant sardine Sardinops sagax, other migrant and resident small pelagic fish species, and interactions with predators, as well as the socio-economic impacts of the sardine run on the local people. Enrichment of KZN coastal waters with organic nitrogen contained within the sardine is compared with alternative sources of nitrogen such as upwelling, river, sewage and stormwater runoff, and groundwater discharge. The sardine run appears to contribute most nitrogen to this system—96 000 t compared to 500–3 300 t for each of the other significant sources at trophic level 2, although upwelling estimates are extremely wide. Nonetheless, the majority of surviving sardine, their young and predators return southwards, suggesting that the nett export of nitrogen to KZN waters during the run is likely to be of a similar order of magnitude as that from other sources. Further, whereas the sardine supply of nitrogen is exclusively during winter, the bulk of the riverine input is in summer, thus ensuring that nitrogen supply in the region is maintained at fairly constant levels throughout the year. Competition for food between small pelagic fish is minimised by resource partitioning, but further dietary data are needed for resident species. Although interactions between sardine and top predators must exist, further studies are needed to confirm links between top predator life cycles and the sardine run. The estimated value of sardine as a tourist spectacle is compared to that from a seasonal beach-seine or boat-based purse-seine fishery for this species. Whereas the estimated value of the sardine as a tourist attraction appears substantially higher than could be derived from catching them, the small-scale beach-seine fishery itself draws tourists and also provides limited, seasonal employment opportunities. 相似文献
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Temporal variability in predator presence around a fin fish farm in the Northwestern Mediterranean Sea 
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下载免费PDF全文 Bruno Díaz López 《Marine Ecology》2017,38(1)
Recently, aquaculture has generated worldwide interest as a result of the overexploitation of wild stocks combined with a growing international demand for fish and seafood products. Wild fish attracted to the marine fish farms, together with the presence of the farmed fish, are powerful attractants to predators that normally feed on similar or identical fish stocks in nature. This 9‐year study describes for the first time in Mediterranean waters the temporal variability of mammalian and avian predators in a coastal fin fish farm. In all, 99 months (1062 days during 36 consecutive seasons) were spent in the field. By examining the results of this study, it is clear that species as seagulls, shags, bottlenose dolphins and grey herons (considered to cause economic loss in aquaculture owing to direct predation) interact regularly with the fish farm. Although bottlenose dolphins and grey herons were not the most important of all predator species, predatory interactions with the fish farm occurred with what seems to be increasing regularity. Another result observed is the possible bottlenose dolphins’ attraction caused by the harvesting operations in the fish farm. The fish farm offers an alternative food source for predators; hunting at fish farms usually requires less effort on the part of the predator, and becomes a more attractive option than hunting wild fish over wide ranges. During the period of this study, individually identified dolphins feeding were regularly observed feeding on discarded fish from fish farm workers during harvesting operations, supporting the possibility that some individuals are habituated to this food supply. Based on the evidence presented in this paper, it is recommended that strategies for the management of both the aquaculture industry and marine mammal populations should take the results of this study into consideration. 相似文献
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Dietary Studies on the Predatory Fishes of the Norman River Estuary, with Particular Reference to Penaeid Prawns 总被引：1，自引：0，他引：1
The predatory fish community and their prey in the Norman Rivere estuary, Gulf of Carpentaria Australia, are compared with the communities of other tropical inshore areas, to investigate patterns of predation in tropical inshore areas particularly in relation to penaeid prawns. Abiotic factors (turbidity, freshwater input) and diversity of habitat types affect the composition of both prey and predator communities, resulting in large differences in the communities of tropical inshore waters. The stomach contents of 2059 predatory fish from the Norman River estuary were analysed over four sampling trips in the wet and dry seasons. The stomachs of 61% (1255 fish) of 54 species contained a total of 676·2 g (dry weight) of food, while 39% (804 fish) were empty. Teleosts were the main component of the diet (by dry weight) of 13 of the 22 species analysed, followed by annelids for two species. Five species had only teleosts in their stomachs. Most predator species ate benthic or bentho-pelagic prey, while three species—Rhizoprionodon taylori, Scomberoides commersonianusandLeptobrama mulleri—ate mainly pelagic prey. Although 19 species ate some penaeids, onlyPolydactylus sheridaniate little else. This species,Lates calcariferandEleutheronema tetradactylumate 94·5% of all the penaeid prey and 97·9% of all the commercially important penaeid prey recorded in the study. Penaeid predation indices (calculated from gillnet catch rates, proportion of penaeids in the diet and a consumption rate of 3% body weight per day) were 0·23 g of penaeid per net-metre per day forP. sheridani, 0·15 forL. calcariferand 0·03 forE. tetradactylum. Commercially important penaeid predation indices were 0·11, 0·13 and 0·01, respectively. These values are intermediate between those previously recorded for the main penaeid predators in other inshore areas of the Gulf of Carpentaria (Embley River estuary and Groote Eylandt). 相似文献