Topic
Bathylagus
About: Bathylagus is a research topic. Over the lifetime, 28 publications have been published within this topic receiving 383 citations.
Papers
TL;DR: Adult mesopelagic fishes are described from acoustic and trawl surveys over the full-depth of 500 m at 169 stations on a longitudinal transect crossing the Humboldt Current at 50–200 nautical miles off Peru during austral spring (October–November) of 2001, 2002 and 2003.
Abstract: The horizontal and vertical distributions of adult mesopelagic fishes are described from acoustic and trawl surveys over the full-depth of 500 m at 169 stations on a longitudinal transect crossing the Humboldt Current (03°45′S, 81°76′W and 18°23′S, 71°13′W) at 50–200 nautical miles off Peru during austral spring (October–November) of 2001, 2002 and 2003. A total of 2,952 kg of fishes was collected, which included 13 families, 23 genera and 28 species. The mesopelagic community is dominated by the families Phosichthyidae (Vinciguerria lucetia), Myctophidae (Diogenichthys laternatus and Lampanyctus idostigma) and Bathylagidae (Leuroglossus urotranus), accounting for 60.4, 12.8 and 3.7%, respectively, of the total catch. Based on horizontal distribution patterns these species were categorized into three groups, i.e. northern-central upwelling front group (L. urotranus, Nemichthys fronto and Scopelarchoides nicholsi), Southern upwelling front group (Hygophum reinhardti, Myctophum nitidulum, Paralepis sp and Scopeloberyx sp.) and pan-Humboldt Current group (V. lucetia, D. laternatus, L.
(Nannobrachium)
idostigma, L. omostigma, M. aurolaternatum, Triphoturus oculeus, Bathylagus
(Melanolagus) berycoides, Leuroglossus stilbius, Argyropelecus affinis, Sternoptyx obscura, Melamphaes sp., Stomias sp. and Scopelosaurus sp.). Nighttime vertical distribution was characterized by a single abundance peak in the upper 50 m. Daytime patterns showed three peaks of abundance: an upper peak, in the upper 100 m, a midwater peak between 200 and 400 m, coinciding with an oxygen minimum zone, and a deeper peak between 400 and 500 m. V. lucetia was dominant in the upper and midwater peaks while myctophids, other planctivorous and piscivorous fishes were distributed in the midwater. Acoustic back-scattered energy (S
a) was ubiquitous in the region. Maximum S
a was mainly located between 11° and 18°S during day and night. V. lucetia is a significant component of the sound-scattering layers in the Humboldt Current Region off Peru.
55 citations
TL;DR: Significant inter-seasonal and inter-fishing-ground differences in diet were found, but dietary composition was not related to fishing depth, fish size or the time of day of capture.
Abstract: A total of 1423 stomach samples were taken from Patagonian toothfish, Dissostichus eleginoides, caught by bottom trawls at two fishing grounds near Macquarie I., over three fishing seasons. Fish were caught at depths ranging from 500 to 1290 m, and ranged in size from 310 to 1490 mm total length. The 462 stomach samples (32%) that contained prey items indicated that toothfish preyed on a broad range of species including fish, cephalopods and crustaceans (58%, 32% and 10% biomass, respectively), suggesting that they are opportunistic predators. The bathypelagic fish Bathylagus sp. was the most important fish prey (14% dietary biomass); however, nototheniid, macrourid, morid and myctophid fish were also taken. The squid Gonatus antarcticus was also an important prey species (16% biomass), and many other cephalopod species were taken in low frequency. Prawnlike crustaceans (Nematocarcinidae, Mysididae, Sergestidae and Euphausiidae) were the most important crustaceans taken (9% of prey biomass). Significant inter-seasonal and inter-fishing-ground differences in diet were found, but dietary composition was not related to fishing depth, fish size (with the exception of one fishing ground in one season) or the time of day of capture. Comparison with other studies reveals biogeographical differences in the diet of toothfish.
40 citations
TL;DR: A multidimensional scaling (MDS) ordination and similitude dendograms revealed changes in the larval fish community structure influenced by hydrographic conditions, indicating the importance of the distance from shore and production processes (represented by chlorophyll-a) on the assemblage distributions.
Abstract: This paper identifies the larval fish community distribution, emphasizing non-commercial species, in the coastal zone and the adjacent oceanic area off the Peninsula de Mejillones (23° S, 71° W) during the 1997 El Nino. We performed one survey in the austral summer (January) and one in the austral winter (July). In January, cold, upwelled water dominated the area off the Peninsula de Mejillones with a cold-water filament extending 60 nm offshore. In July, warm Subtropical Surface Waters affected the area. We identified a total of 56 taxa, which included taxa from different adult habitats (coastal, epipelagic, epi-mesopelagic and mesopelagic). The most abundant species were Engraulis ringens (18% and 21%), Bathylagus sp. (4% and 5%), Diogenichthys laternatus(12% and 39%), Lampanyctus parvicauda (9% and 2%), Triphoturus mexicanus (14% and 3%) and Vinciguerria spp. (21% and 23%), in January and July, respectively. A multidimensional scaling (MDS) ordination and similitude dendograms revealed changes in the larval fish community structure influenced by hydrographic conditions. The rank correlations between the assemblage similarity matrix and the physical variables matrix indicate the importance of the distance from shore and production processes (represented by chlorophyll-a) on the assemblage distributions. Off the Mejillones' coast, there is a complex spatial and temporal hydrographic system where ichthyoplankton of coastal and oceanic fish species coexist. Despite both short-term and longer-term disruptive oceanographic processes (e.g., mesoscale filaments, El Nino events), it seems that the numerically dominant species persist in the area due to their various behavioral strategies and physiological adaptations.
27 citations
TL;DR: In this paper, the role of gelatinous material as a possible buoyancy mechanism in an energy-poor habitat is discussed, and it is shown that four species of swimbladderless non-migrators (Bathylagus pacificus, B. ochotensis, Stenobrachius leucopsarus, Tarletonbeania crenularis and Diaphus theta) have no such deposits.
Abstract: Mesopelagic fishes were collected from depths of 400 to 900 m off Oregon (USA) in September 1983, October 1985 and June 1989. Species of mesopelagic fish without diel vertical migrations (non-migrators) are known to have high body-and muscle-water contents relative to epipelagic and vertically migrating mesopelagic species. This characteristic is reported to correlate with low food availability. Through histology, we show that four species of swimbladderless non-migrators (Bathylagus pacificus, B. milleri, Tactostoma macropus and Chauliodus macouni) have large deposits of gelatinous material which stain positively for acidic glycosaminoglycans (GAGs) and negatively for lipid and protein. GAGs are highly hygroscopic and are thus responsible in part for the high body-water content of these species. The material is located between myotomal (swimming) muscle cells, along the dorsal midline and surrounding the spine in all four species, and the two Bathylagus species have an additional subcutaneous layer. The subcutaneous layer of B. pacificus has very high (96%) water, low protein (3%) and low ion contents and is positively buoyant, unlike myotomal muscle (89% water, 6.7% protein, negatively buoyant). In contrast, four species of vertical migrators (B. ochotensis, Stenobrachius leucopsarus, Tarletonbeania crenularis and Diaphus theta) have no such deposits. The role of this gelatinous material as a possible buoyancy mechanism in an energy-poor habitat is discussed.
22 citations
1 Jan 2000
TL;DR: In this paper, the distribution of adults and larvae of two equatorial mesopelagic fish species Bathylagus argyrogaster and Hygophum macrochir was found to be consistent with hydrographic data.
Abstract: Fish larval distributions support the hypothesis that East: Atlantic "upwelling" undercurrents are interconnected, and can entrain plankton from the Equatorial Undercurrents towards temperate latitudes. This conclusion is based on historic and recently collected data on the distribution of adults and larvae of mainly two equatorial, mesopelagic fish species Bathylagus argyrogaster and Hygophum macrochir and consistent with hydrographic data. Along the continental slope these larvae occur 440 to 920 km polewards of the reproductive ranges of their adults. Larval B. argyrogaster occurs mainly below the thermocline and reaches farther polewards than larval H. macrochir, which dwells mainly at thermocline depths. At tropical latitudes the larvae of both species occur frequently, and within a generally poleward flow. Immediately polewards of the Cape Verde Frontal Zone, and Angola-Benguela Frontal Zone, respectively, the larvae become rare and more deeply distributed. At these fronts the poleward flows are thought to submerge below the equatorward flows of the Canary Current and Benguela Current, and to form theslope-undercurrents of the Northwest and Southwest African upwelling systems. Larvae in these undercurrents reach minimum latitudes of 22 degrees N and 23 degrees 30'S. At the poleward flanks of East Atlantic cyclonic gyres,such as the Guinea Dome, Central Mauritanian Gyre, and Angola Dome, retroflections of the poleward current systems occur, also entraining and transporting larvae offshore.
20 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2014 | 2 |
| 2008 | 1 |
| 2006 | 3 |
| 2003 | 4 |
| 2002 | 1 |
| 2000 | 1 |