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1.
The food and feeding habits of hoki (Macruronus novaezelandiae), southern blue whiting (Micromesistius australis), javelin fish (Lepi‐dorhynchus denticulatus), ling (Genypterus blacodes), smooth rattail (Coelorinchus aspercephalus), silverside (Argentina elongata), and small‐scaled notothenid (Notothenia microlepidota) sampled from the Campbell Plateau in 1979 were examined. The importance of prey items in the diet has been assessed by an ‘index of relative importance’, which combines measurements of frequency of occurrence, number, and weight of prey. Hoki, southern blue whiting, and javelin fish are pelagic feeders. Hoki preyed largely on natant decapod crustaceans, amphipods, and myctophid and photichthyid fishes. The main prey of southern blue whiting were amphipods, natant decapods, and euphausiids. Javelin fish fed on natant decapods, amphipods, and small squid. Seasonal and regional differences in feeding, and dietary changes with length of fish were evident. Ling, smooth rattail, silverside, and small‐scaled notothenid are predominantly benthic feeders. Ling preyed on natant decapods, macrourid fishes, and small hoki. The diet of rattail comprised natant decapod crustaceans, opal fishes (Hemerocoetes spp.), and poly‐chaetes. Silverside fed almost solely on salps. Salps, amphipods, brachyuran crustaceans, and opal fishes were the main prey of small‐scaled notothenid.  相似文献   

2.
The diet of the squid Nototodarus sloanii was determined from examination of stomach contents of 388 specimens of 14.3–41.0 cm dorsal mantle length sampled at depths of 211–760 m on the Chatham Rise, New Zealand. Prey items were predominantly mesopelagic fishes, with some crustaceans and cephalopods. The most important prey species identified was Maurolicus australis, followed by Lampanyctodes hectoris, and unidentified squids (Teuthoidea). Multivariate analyses using distance‐based linear models, non‐parametric multi‐dimensional scaling, analysis of similarities, and similarity percentages, indicated crustaceans were more important in the diet of smaller squid (83–480 g), the fish component of the diet was dominated by L. hectoris on the east Chatham Rise and M. australis on the west Chatham Rise, and there may be a difference in diet with sex, with crustaceans and cephalopods more important for females. The results indicated that N. sloanii, similar to other ommastrephid squids, foraged primarily in the mesopelagic layers.  相似文献   

3.
The feeding behaviour of two potentially competing species, the longspine snipefish, Macroramphosus scolopax, and the boarfish Capros aper was examined. While both species are very abundant along the Mediterranean coast and are regularly caught by demersal trawlers, they are of no commercial value. The diets of boarfish and longspine snipefish were investigated from samples collected between January 2001 and May 2002. Variations in the diet with fish size and season, as well as diet overlap and diversity were explored. Mysid shrimps, amphipods and gastropods were the most important food items in the diet of longspine snipefish. During ontogenetic development, M. scolopax occupies different trophic levels: the diet shifts from being predominantly composed of mysids (Anchialina agilis, Lophogaster typicus, Erythrops sp., Leptomysis spp.) in the smaller longspine snipefish [<6.5 cm total length (TL)] towards decapods (Anapagurus laevis) and amphipods (Leucothoe incisa, Eusirus longipes, Hyperidea) in the larger individuals (>6.5 cm TL). Crustacean decapods and copepods were the most important prey in the stomachs of boarfish. Mysids (Lo. typicus), euphausiids and nematodes were present in the larger individuals (>8 cm TL). A more generalist diet, still containing copepods, crustacean decapods, gastropods (Limacina retroversa) and a large variety of amphipods (e.g. Phtysica marina, Stenotoe bosphorana) and mysids (e.g. A. agilis, Leptomysis spp., Erythrops sp.), dominated the diet of C. aper between 2 and 8 cm TL. Diet overlap between longspine snipefish and boarfish was very low and the differences in stomach species diversity were explained by season and fish size.  相似文献   

4.
Scavengers perform an important role in deep-sea ecosystems, recycling carrion. However, scavenged material can be difficult to discern from predation. The synaphobranchid eel Diastobranchus capensis Barnard, 1923, is common bycatch in deep-water fisheries for orange roughy (Hoplostethus atlanticus Collett, 1889) in New Zealand waters. Despite anecdotal reports of scavenging in D. capensis, their ecology and feeding are little known. Scavenged material was estimated to be approximately 39 per cent (by weight) of the diet of D. capensis from northeastern Chatham Rise, New Zealand, from water depths of 1062–1196 m. Scavenged material was defined as fragmentary food items from animals and plants either not normally available to the eel, or from animals larger than the eel consuming them (e.g., fish heads and tails, spent squid spermatophores, beaks and tentacle crowns, and seaweed). D. capensis were primarily piscivorous, with the diet supplemented by squid, natant decapods and mysids. The weight or number of food items did not increase with the size of the eel, nor was there any major ontogenetic shift in the composition of the diet. D. capensis probably plays an important role in mid-slope communities, recycling carrion.  相似文献   

5.
Plankton samples from the Chatham Rise, Pukaki Rise, and Campbell Plateau provided information on the young stages of a number of poorly known New Zealand fish species, and on the presence of a large spawning area of barracouta, Thyrsites atun, over the Mernoo Bank, The Chatham Rise was more important as a spawning area than the areas further south.  相似文献   

6.
The feeding habits of the deep-sea blue–red shrimp Aristeus antennatus were determined based on the analysis of 1047 stomach contents, sampled in the Greek Ionian Sea (E. Mediterranean). The diet of this economically and biologically important decapod was studied in relation to the season, size class and sex. The diet of A. antennatus consisted of 54 different prey categories, and belonged mainly to smaller crustaceans (e.g. natantian decapods, euphausiids, tanaidaceans), molluscs, polychaetes, chaetognaths and, to a lesser extent, fishes. The above prey categories consisted of 71–82% of the relative abundance and total occurrence for males and 61–81% for females. Females seemed to be better fed than males (stomach fullness, food quality). A. antennatus displayed a highly diversified diet and the different feeding patterns were discussed. Diet composition showed slight seasonal fluctuations. The observed slight differences on A. antennatus diet among the western, central and eastern Mediterranean could be attributed to the more oligotrophic character of the eastern part of the basin. The principal factors driving the changes in the feeding strategy of this decapod among the seasons are the increased energy demands related to sexual requirements and the food availability in the marine environment. The ontogenetic changes in the shrimp's diet were relatively clear. Larger individuals exhibited selecting prey with a good swimming capacity (e.g. fishes), while the smaller individuals consumed prey with low mobility (e.g. copepods, ostracods).  相似文献   

7.
Data on the food consumption, feeding activity and periodicity of two burrowing fish, the congrid eel Gnathophis mystax (Delaroche, 1809) and the false moray Chlopsis bicolor Rafinesque, 1810 are presented. In all, 455 specimens were collected by bottom trawl in the central Mediterranean Sea at depths ranging from 140 to 160 m during four 24‐h day–night sampling cycles. The diet of G. mystax and C. bicolor was investigated by means of stomach content analysis. Diet varied significantly with length and maturity stage. During ontogenetic development G. mystax occupied different trophic levels: diet shifted from amphipods, predominantly in the smaller congrid eels [<25 cm total length (TL)] to fish in the larger individuals (>30 cm TL). Before the transition to the icthyophagous phase, the congrid eel showed a more generalistic foraging behaviour where decapods (Solenocera membranacea, Parapenaeus longirostris, Alpheus glaber), cephalopods (Sepiola spp. and Alloteuthis media), benthic (Gobiidae, Callionymus maculatus, Arnoglossus laterna) and benthopelagic fish (Argentina sphyraena) dominated the diet. Smaller C. bicolor (<25 cm TL) fed primarily on amphipods and cephalopods; bigger specimens fed also on decapods both natantian (A. glaber, Processa canaliculata) and reptantian (Medorippe lanata, Goneplax rhomboides). Daily ration values, computed from the Eggers method, ranged from 2.48% to 2.99% wet body weight for C. bicolor and G. mystax, respectively. Diel patterns in stomach fullness and the trophic niche overlap between the two species were also discussed.  相似文献   

8.
A number of pathological abnormalities previously unrecorded in New Zealand fishes are described. A silver trevally (Pseudocaranx dentex) captured from the Bay of Islands exhibited swim bladder ectasia. Black oreo (Allocyttus niger) and smooth oreo (Pseudocyttus maculatus) had cysts of unknown aetiology (CUEs) in the gills at prevalences up to 76% and 81%, respectively, in some fishing areas. The CUEs appear long lived and may have some utility for stock discrimination. A hoki (Macruronus novaezelandiae) with X‐cell pseudotumours in the gill was recorded from the Chatham Rise. Alfonsino (Beryx splendens) had conspicuous Kudoa sp. cysts in the gills at prevalences of up to 28%. Smelt (Retropinna retropinna) from the Waikato River were infected with a xenoma forming, Glugea‐like microsporidian.  相似文献   

9.
Stomachs from the sharks Dalatias licha, Centrophorus squamosus, Centroscymnus owstoni, Centroselachus crepidater, Proscymnodon plunketi, and Galeorhinus galeus were sampled from three research trawl surveys on Chatham Rise, east of New Zealand. Between 14 and 50 stomachs were examined for each species, of which 8–62% were empty. Prey were visually identified in 80 stomachs, and by DNA barcoding in a further 28 stomachs. The use of DNA methods allowed the identification of chunks of flesh found in the stomachs of D. licha and P. plunketi, and nearly doubled the rate of data accumulation for D. licha, C. squamosus, and C. owstoni. Between 84 and 223 stomachs were estimated to be needed to measure 90% of the extrapolated total prey richness. The prey of D. licha, C. squamosus, and P. plunketi were predominantly benthic or demersal fishes and cephalopods. The prey of C. owstoni and C. crepidater were predominantly mesopelagic fishes and squids. G. galeus foraged throughout the water column. Scavenging of discards from commercial fishing vessels was likely in C. squamosus, P. plunketi, and G. galeus. The diet of all species except C. crepidater was dominated by the commercially important benthopelagic species hoki Macruronus novaezelandiae.  相似文献   

10.
We describe the distribution and abundance of the midwater fish community, between 200 m and 500 m, in the North Pacific. The main area of interest was the Subarctic Pacific gyres, but we include species from the Bering Sea and the Sea of Okhotsk. There were 196 species identified in each gyre, 38 of which were common to both gyres. The most abundant species belong to the family Myctophidae and the most ecologically important myctophid probably is Stenobrachius leucopsarus. This species could have a biomass of approximately 21 million tonnes (t) in the Subarctic Pacific (including the Bering Sea and Sea of Okhotsk). S. leucopsarus is a small (about 8 cm maximum length) fish that lives up to 7 years. It is prey for a variety of other fishes, birds and mammals and may migrate into the mixing layer each evening where it feeds mainly on euphausiids and copepods.The total abundance of midwater fishes appears to be large relative to total catches of other fish in the same areas. The vertical migratory behaviour of some of the residents provides a mechanism to transfer production out of the mixing layer. The movement into the surface layer by some fishes at night indicates that dynamic changes occur in the midwater community between the day and night, and the ecosystem dynamics in the surface layer are different in the day and in the night. This behaviour and the huge biomass relative to commercial species means that the dynamics of fish communities in the Subarctic Pacific are complex and need to be studied over a 24 hour period. The large biomasses may eventually attract commercial interest, thus it is important to establish international, cooperative programs now to learn more about the dynamics of these populations and the relationships with other species.  相似文献   

11.
A calculation of the area of the New Zealand 200 nautical mile Exclusive Economic Zone is presented with definitions, cartographic methods, and calculations based on areas of quadrilaterals of the earth's surface of 1° extent in latitude and longitude. An area of 1 181 487 square international nautical miles (4 053 049 km2), ± 0.377%, includes enclaves adjacent to the Chatham Rise and the Pukaki Rise retained for assessments related to fisheries research programmes.  相似文献   

12.
Abstract. The waters surrounding the Pribilof Islands are an important nursery ground for juvenile walleye pollock (Theragra chalcogramma), an important forage fish in the pelagic food web of the productive Bering Sea shelf region. The diet of juvenile pollock was studied in two consecutive years along a transect line crossing from a well‐mixed coastal domain, through a frontal region to stratified water farther offshore. Variability in stomach fullness was high and evidence for increased feeding intensity in the front was weak. Prey diversity and prey size generally increased with increasing fish size, shifting from predominantly small copepods to larger, more evasive prey items such as euphausiids, crab megalopae and fish. The diet of the fish reflected changes in the relative abundance of copepods and euphausiids in the prey fields between years. Juvenile pollock showed increased feeding rates at dusk, and stomach fullness as well as prey condition were generally lowest just before sunrise; however, the proportion of euphausiids increased in the diet of pollock caught at night, suggesting that some food was also ingested during darkness. Juvenile pollock and their euphausiid prey both vertically migrated above the thermocline at night, although each had a different daytime depth.  相似文献   

13.
Abstract. The stomach contents of poor cod, Trisopterus minutus capelanus (Lacepède), were taken at monthly intervals off the eastern coast of the Gulf of Valencia (Spain). A total of 1276 were analyzed to determine diet according to fish size and season. The basic food consists of crustaceans (Mysidacea and Decapoda) and teleosts. Feeding habits varied with size: decapods and fishes were more abundant in the stomachs of larger specimens. Little seasonal variation in food habits was recorded.  相似文献   

14.
The aim of the research was to investigate the diet of herring at different stages of its life cycle. For that purpose feeding of 0-group and immature herring in the Barents Sea, as well as of mature fish from the Norwegian Sea, was studied. 0-Group herring was sampled in the Barents Sea in August–September 2002–2005 during the international 0-group and trawl-acoustic survey of pelagic fish, as well as during the trawl-acoustic survey of demersal fish in November–December 2003–2004. Stomach samples of immature herring (1–3 years) were collected in late May and early of June 2001 and 2005 in the south-western part of the Barents Sea during the trawl-acoustic survey for young herring. Stomach samples of mature herring were collected in the Norwegian Sea in 1996, 1998, 1999, 2001, and 2002 in the course of the international trawl-acoustic survey of pelagic fish. Feeding intensity of herring of all age groups varied considerably between years and this was probably associated with availability and accessibility of their prey. The 0-group herring was found to have the most diverse diet, including 31 different taxa. In August–September, copepods, euphausiids, Cladocera, and larvae Bivalvia were most frequent in the diet of 0-group herring, but euphausiids and Calanus finmarchicus were the main prey taken. In November–December, euphausiids and tunicates were major prey groups. It was found that C. finmarchicus in the diet of 0-group herring was replaced by larval and adult euphausiids with increasing fish length. C. finmarchicus was the principal prey of immature herring and dominated in the diet of both small and large individuals and mainly older copepodites of C. finmarchicus were taken. Larval and adult euphausiids were found in stomachs of immature herring as well, but their share was not large. The importance of different prey for mature herring in the Norwegian Sea varied depending on the feeding area and length of the herring. On the whole C. finmarchicus and 0-group fish were the most important prey for mature herring diet, but fish prey were only important in a small sampling area. Hyperiids, euphausiids, tunicates, and pteropods were less important prey, and in 2002 herring actively consumed herring fry and redfish larvae.  相似文献   

15.
Several sediment samples collected from the crest and slope of the Chatham Rise, and from the Chatham Islands, to the east of New Zealand, contain Globigerina linaperta‐Globorotalia increbescens foraminiferal faunas of upper Middle and middle Upper Eocene age. The foraminiferal faunas from the Chatham Islands, which include Rectuvigerina, Latibolivina, Dyocibicides, Discorbinella, Patellina, and Wadella, indicate shallow‐water palaeodepths, probably equivalent to the outer shelf (50–150 m). A faunal assemblage from near the crest of the rise is likewise indicative of shallow water, although distinct differences in the benthonic foraminiferal ifauna suggest slightly deeper‐water biofacies than the Eocene of the Chatham Islands. In contrast, a fauna of similar age from 1,100 m on the southern slope of the Chatham Rise contains a much deeper‐water benthonic foraminiferal assemblage including Osangularia, Vulvulina, Stilostomella, hispidocostate Uvigerina, and smooth‐shelled Bulimina, indicative of lower middle bathyal depths (1,500–2,500 m).

The nature and distribution of the assemblages, together with previous work by Norris (1964) and Cullen (1965), indicates that the Chatham Rise has been a significant structure since at least the Middle Eocene, with some uplift occurring since then.  相似文献   

16.
本研究基于2013年夏季“大洋一号”船大洋第30航次西南印度洋海区科学考察走航线路,对西南印度洋21°S到38°S海域表层浮游动物群落进行连续采样调查,研究了该海域表层中型浮游动物群落结构和物种多样性及空间分布格局。结果显示,研究海域表层中型浮游动物群落组成包括:桡足类、磷虾类、端足类、十足类、介形类、毛颚动物、被囊类、异足类、翼足类、刺胞动物及多毛类等11大类,总计50属69种;优势类群为桡足类(69%)和磷虾类(27%)。多样性指数随经度和纬度的变化特征:H′、D多样性指数及J均匀度指数随纬度的升高均呈下降趋势;在经度梯度上,几种多样性指数也大致呈现出东高西低的趋势。聚类分析表明,研究区可大致以36°S附近为界划分为南部和北部两大类群,分别以北部桡足类(平均粒径小),南部磷虾类(平均粒径大)Euphausia属为优势群落。群落相似性结果反映出,南部类群与南极克罗克海峡和南极长城湾水域群落,北部类群与西北印度洋海域群落的联通性不高。  相似文献   

17.
Measurements of total dissolved arsenic (As(III+V)) and antimony (Sb(III+V) and their simple methylated species are presented for samples collected from three vertical profiles and along three surface transects in the Chatham Rise region, east of New Zealand. As(III+V) concentrations showed a slight increase with depth (16–17 nM at 25 m to 20 nM at 100 m) whereas Sb(III+V) concentrations were conservative with depth (1.02–1.12 nM). Along the three surface water transects, As(III+V) and Sb(III+V) concentrations showed little variation, with average concentrations of 18±2 and 0.99±0.05 nM, respectively. Inorganic arsenic was not correlated with orthophosphate (r2=0.01). Monomethyl- and dimethyl-arsenic (MMAs, DMAs) concentrations (0.04–0.01 and 0.65–0.07 nM, respectively) decreased with depth, suggesting surface water production by biota and degradation at depth. Along the Chatham Rise transect, DMAs concentrations increased on the Rise (0.65 nM maximum) compared to waters north and south of the Rise (∼0.22 nM). Fluctuation in MMAs concentrations were also seen for water samples collected on the Chatham Rise. Monomethyl-, dimethyl- and trimethyl-antimony (MMSb, DMSb, TMSb) species were detected in water samples collected along all the three surface water transects suggesting surface water production by biota. Concentrations of MMSb, DMSb and TMSb in water samples were fairly constant along all the three surface transects (0.06–0.07, 0.015–0.025 and 0.005–0.015 nM, respectively), showing no significant enrichment on the Chatham Rise. These arsenic and antimony results support the current global view that inorganic As and Sb are conservative and the methyl species are of biological origin.  相似文献   

18.
The winter distributions of mesopelagic fishes, crustaceans, and cephalopods across the Subtropical Convergence east of New Zealand are shown to reflect the hydrological changes associated with convergence of Subtropical and Subantarctic Surface Waters. Samples collected in the upper 400 m in each of these water masses and in mixed water over the Chatham Rise contained members of faunal associations apparently characteristic for each area. The area of strongest hydrological change was characterised, at least for fishes and crustaceans, by a considerable decrease in species richness. Use of cluster analysis confirmed the clear correpondence between geographic species associations and water masses.  相似文献   

19.
To investigate regional drivers of spatial patterns in macro- and meio-faunal community structure (abundance, biomass and taxonomic diversity) and ecosystem function (sediment community oxygen consumption [SCOC]), we sampled two regions in close proximity on New Zealand's continental margin—the Chatham Rise and the Challenger Plateau. Sites (n = 15) were selected in water depths ranging from 266–1212 m to generate a gradient in sedimentary properties and, in particular, surface pelagic productivity. Both macro- and meio-fauna abundance and biomass was 2–3.5 times higher on the Chatham Rise than on the Challenger Plateau, reflecting regional differences in pelagic primary production. We also found significant inter- and intra-regional differences in macro-fauna taxonomic diversity with two distinctive site groupings in each region. Univariate and multivariate measures of macro-fauna community attributes were most strongly correlated with sediment photosynthetic pigment (explaining 24%–59% of the variation). Sediment pigment content was as equally important in explaining meio-fauna community structure (36%–7%). Unlike community structure, SCOC was most strongly correlated with depth (44%), most likely reflecting temperature effects on benthic metabolism. Our results highlight the importance of a benthic labile food supply in structuring infaunal communities on continental margins and emphasise a tight coupling between pelagic and benthic habitats.  相似文献   

20.
Short spatio–temporal variations in the feeding intensity and the diet of the European hake, Merluccius merluccius, together with the abundance of their potential prey were studied between August 2003 and June 2004 at two locations, northwest (Sóller) and south (Cabrera), off the island of Mallorca (Balearic Islands, Western Mediterranean) at depths between 150 and 750 m. The two areas present different oceanographic conditions. Hake was mainly distributed along the shelf-slope break and the upper slope (between 166 and 350 m) where recruits (TL<18 cm) were dominant. The hake's diet varied as a function of size. Recruits fed mainly on micronektonic prey, and the diet was influenced primarily by seasonality, with two dietary patterns (identified by MDS analyses) corresponding to August–September 2003 (summer) and to November 2003/February–April 2004 (autumn–winter). The summer pattern was consistent with a thermally stratified water column, while November and April were consistent with homogenized temperature and salinity throughout all the water column. The main prey of recruits were the euphausiid Meganyctiphanes norvegica and the midwater fish Maurolicus muelleri in autumn–winter and myctophids (mainly Ceratoscopelus maderensis) in summer. In contrast to recruits, the geographic factor (NW vs. S) was the main factor influencing the diets of post-recruits (TL between 18 and 21.9 cm) and adults (TL?22 cm). Hake recruits (and to a lesser extent post-recruits) and their preferred prey occupied different depth ranges during daylight periods. Meganyctiphanes norvegica and Ceratoscopelus maderensis were, for instance, distributed as much as 500 m deeper than hake that had eaten them. All these trends were especially obvious at NW, an area with a more abrupt slope and with a greater influence by northern winter intermediate water (WIW) inflow in early spring than the S area. These factors probably enhanced micronekton aggregation in April, when feeding intensity (stomach fullness) increased among recruits and post-recruits only at NW. All these factors may have a crucial role in the diet, distribution and probably recruitment success of small hake. Biological factors were also important in trophic shifts in the diet and feeding of hake. Multi-linear regression models pointed to a trend of higher fullness with higher hepato-somatic index (HSI). Therefore greater food consumption by hake may enhance its metabolic condition. Within the framework of shelf-break and slope ecology, we show how the ‘boundary’ mesopelagic community inhabiting the middle slope sustains the trophic requirements of hake, a species distributed at shallower depths along the shelf-slope break. Mesopelagic euphausiids and myctophids are often found in the diets of shelf-break fish. Because the boundary mesopelagic community is distributed worldwide, the high levels of fish biomass often found at shelf-slope breaks could be sustained trophically by deeper, offshore mesopelagic communities, an inverse energy transfer from deep to shallow-water marine ecosystems.  相似文献   

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