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Triphoturus mexicanus (Gilbert, 1890). Mexican Lampfish. To 9 cm (3.5 in) SL (Personal communication: Scripps Institution of Oceanography Fish Collection, La Jolla, California). British Columbia (Gillespie 1993) to off southern Mexico (Rodr��guez-Gra��a et al. 2004), including Gulf of California (De La Cruz-Ag��ero and Galv��n-Maga��a 1992). Depth: surface to perhaps 2,882 m (9,453 ft) (min.: Personal communication: Scripps Institution of Oceanography Fish Collection, La Jolla, California; max.: Personal communication: Los Angeles County Museum of Natural History Fish Collection, Los Angeles, California). Maximum depth poorly known, most captures appear to be in 1,000 m (3,280 ft) or less. Deeper records, such as 4,100 m (13,448 ft) (Personal communication: Scripps Institution of Oceanography Fish Collection, La Jolla, California), are based on the maximum depth fished by a midwater trawl and may represent a catch shallower than the maximum depth. Triphoturus oculeus (Garman 1899) has been considered to be synonymous with Triphoturus mexicanus Gilbert, 1890. However, on the basis of both DNA and larvae characters Rodr��quez-Gra��a et al. (2004) separated the two species. Triphoturus oculeus is found from 13��N to 35��S., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 73, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Gillespie, G. E. (1993) An updated list of the fishes of British Columbia, and those of interest in adjacent waters, with numeric code designations. Canadian Technical Report Fisheries and Aquatic Sciences, 1918.","Rodriguez-Grana, L., Herrera, G., Herrera, L. & Castro, L. R. (2004) Divergence of two forms of Triphoturus in the eastern Pacific based on mtDNA cytochrome b gene sequence and larval morphology. Journal of Fish Biology, 64, 1455 - 1461. https: // doi. org / 10.1111 / j. 0022 - 1112.2004.00413. x","De La Cruz-Aguero, J. & Galvan-Magana, F. (1992) Peces mesopelagicos de la costa occidental de Baja California sur y del Gulfo de California. Anales del Instituto de Ciencias del Mar y Limnologia, 19, 25 - 31."]}

Myctophids are key members of mesopelagic communities with a world biomass estimated at 600 million tons. They play a central role in oceanic food webs and are known to perform diel vertical migrations, crossing the thermocline and reaching the oxygen minimum zone, however, very scarce information exists on trace element content in these organisms. Therefore, the trace elemental composition (Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb) of Triphoturus mexicanus and Benthosema panamense specimens was determined. Zinc (Zn) was the most common trace element for both species, T. mexicanus presented 39.8 &micro, g.g&minus, 1 dw and B. panamense 30.6 &micro, 1 dw. Contrasting, for T. mexicanus the less abundant trace element was Ni (0.332 &micro, 1 dw) and for B. panamense was Pb (0.236 &micro, 1 dw). T. mexicanus exhibited significantly higher concentrations of Cr, Cu, Zn and Pb in comparison to B. panamense, and these differences seemed to be related to inherent physiological and/or ecological traits rather than environmental element availability. These diel vertical migrators are crucial in the energy transfer between the deep-sea and epipelagic zones (and vice-versa), and the estimation of the Biomagnification Factor (based on Cu, Zn, Cd and Pb) levels revealed that both T. mexicanus and B. panamense play a major role in trace element transfer to higher trophic levels in the pelagic food web of the Gulf of California.

Stomach contents were analysed for 292 medium size (

The feeding habits of four species of mesopelagic fishes from northern Chile are described: Triphoturus mexicanus, Diogenichtys atlanticus, Vinciguerria lucetia and Cyclothone acclinidens. Samples were captured in September 1988 between 18°25’ and 19°09’S in the South West Pacific. The quantitative and qualitative analyses of the stomach content showed that the species have a zooplanktophagous opportunistic behavior, mainly predating on Crustaceans, especially on Copepods. The evaluation of the trophic spectrum and diversity of T. mexicanus and C. acclinidens suggests that these are nictoepipelagic species, while D. atlanticus and V. lucetia would be typical mesopelagic. Rev. Biol. Trop. 54(2): 613-622. Epub 2006 Jun 01.Se describen los hábitos alimenticios de cuatro especies de peces mesopelágicos del norte de Chile: Triphoturus mexicanus, Diogenichtys atlanticus, Vinciguerria lucetia and Cyclothone acclinidens. Las muestras fueron capturadas en setiembre de 1988 entre 18°25’ y 19°09’ S en el Pacífico suroeste. El análisis cualitativo y cuantitativo del contenido estomacal mostró que las especies tienen un comportamiento zooplantofago oportunista, depredando principalmente crustáceos, especialmente copépodos. La evaluación del espectro trófico y diversidad de T. mexicanus y C. acclinidens sugiere que estas son especies nictoepipelágicas, mientras que D. alanticus y V. lucetia serían mesopelágicas típicas.

Myctophids (Myctophidae) are a group of abundant mesopelagic fishes in the world's oceans and are known as the main feeding resource for several high trophic level predators. Changes in abundance may be related to population size of some commercially important species that feed on them. Only two of the myctophid species reported for the Gulf of California were found in the present study: Benthosema panamense and Triphoturus mexicanus. The highest abundance and biomass of myctophids were found during the warm season (June and September), with B. panamense being the most abundant species (20,954 ind 1000 m-3), as well as the one with highest biomass (17,165.8 g 1000 m-3). B. panamese had a size mode interval of 35-40 mm, while T. mexicanus presented a size mode interval of 40-45 mm; both species had negative allometric growth. During the temperate season (February and April) B. panamense was distributed in the northwest, west, and southern regions around the island, while T. mexicanus was found in the north, west, and southern regions. During the warm season B. panamense was found distributed around the entire island and T. mexicanus was found in the west, south, and east regions of the island. These species are common around San Pedro Martir Island, with the highest values of abundance and biomass occurring during summer upwelling's. Los mictófidos (Myctophidae), son un grupo de peces mesopelágicos abundantes en los océanos del mundo, y se identifican como el principal recurso alimenticio de depredadores con alto nivel trófico. Los cambios en su abundancia pueden relacionarse con el tamaño poblacional de algunas especies de importancia comercial que depredan sobre ellos. En el presente trabajo, de las especies de mictófidos que se reportan dentro del golfo de California, sólo se encontraron dos: Benthosema panamense y Triphoturus mexicanus. En la temporada cálida (junio y septiembre) se presentaron las mayores abundancias y biomasa, siendo B. panamense la especie más abundante (20,954 ind 1000 m-3), así como también la de mayor biomasa (17,165.8 g 1000 m-3). B. panamense se encontró con una moda en el intervalo de tallas de 35-40 mm, T. mexicanus presentó una moda en el intervalo de tallas de 40-45 mm; ambas especies mostraron un tipo de crecimiento alométrico negativo. Con respecto a su distribución, durante la temporada templada (febrero y abril) B. panamense se distribuyó en la región noroeste, oeste y sur, mientras que T. mexicanus se encontró en las regiones norte, oeste y sur de la isla. Durante la temporada cálida B. panamense se encontró alrededor de toda la isla; T. mexicanus se encontró en las regiones oeste, sur y este de la isla. Estas especies son comunes alrededor de la isla San Pedro Mártir, con mayor abundancia y biomasa durante las surgencias de verano.

Myctophids (Myctophidae) are a group of abundant mesopelagic fishes in the world´s oceans and are known as the main feeding resource for several high trophic level predators. Changes in abundance may be related to population size of some commercially important species that feed on them. Only two of the myctophid species reported for the Gulf of California were found in the present study: Benthosema panamense and Triphoturus mexicanus. The highest abundance and biomass of myctophids were found during the warm season (June and September), with B. panamense being the most abundant species (20,954 ind 1000 m-3), as well as the one with highest biomass (17,165.8 g 1000 m-3). B. panamese had a size mode interval of 35-40 mm, while T. mexicanus presented a size mode interval of 40-45 mm; both species had negative allometric growth. During the temperate season (February and April) B. panamense was distributed in the northwest, west, and southern regions around the island, while T. mexicanus was found in the north, west, and southern regions. During the warm season B. panamense was found distributed around the entire island and T. mexicanus was found in the west, south, and east regions of the island. These species are common around San Pedro Martir Island, with the highest values of abundance and biomass occurring during summer upwelling's.

Diel vertical migrators, such as myctophid fishes, are known to encounter oxygen minimum zones (OMZ) during daytime in the Eastern Pacific Ocean and, therefore, have to cope with temperature and oxidative stress that arise while ascending to warmer, normoxic surface waters at night-time. The aim of this study was to investigate the antioxidant defense strategies and heat shock response (HSR) in two myctophid species, namely Triphoturus mexicanus and Benthosema panamense , at shallow and warm surface waters (21 kPa, 20–25 °C) and at hypoxic, cold (≤1 kPa, 10 °C) mesopelagic depths. More specifically, we quantified (i) heat shock protein concentrations (HSP70/HSC70) (ii) antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], and (iii) lipid peroxidation [malondialdehyde (MDA) levels]. HSP70/HSC70 levels increased in both myctophid species at warmer, well-oxygenated surface waters probably to prevent cellular damage (oxidative stress) due to increased oxygen demand under elevated temperatures and reactive oxygen species (ROS) formation. On the other hand, CAT and GST activities were augmented under hypoxic conditions, probably as preparatory response to a burst of oxyradicals during the reoxygenation phase (while ascending). SOD activity decreased under hypoxia in B. panamense , but was kept unchanged in T. mexicanus . MDA levels in B. panamense did not change between the surface and deep-sea conditions, whereas T. mexicanus showed elevated MDA and HSP70/HSC70 concentrations at warmer surface waters. This indicated that T. mexicanus seems to be not so well tuned to temperature and oxidative stress associated to diel vertical migrations. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how different species might respond to the impacts of environmental stressors (e.g. expanding mesopelagic hypoxia) coupled with global climate change.

Prey (chiefly euphausiids and copepods) eaten by two myctophids (lanternfishes) are compared from incidence in fish stomachs and from abundance in the environment. One lanternfish species, Triphoturus mexicanus, lives in the California Current, and the other, T. nigrescens, lives in the central Pacific Ocean. Although these two environments are very different physically and biologically, the feeding habits of the two lanternfishes are surprisingly similar. Prey biomass is 94% euphausiids, 3% copepods, and 3% other organisms for T. mexicanus and 88% euphausiids, 4.5% copepods, and 7.5% other organisms for T. nigrescens; the difference between the fish species is not significant when tested statistically. The two fishes resemble one another in frequency distributions of ingested copepod individuals, copepod species, euphausiid individuals, and euphausiid species. During a single diurnal feeding period, both fishes eat a variety of copepod species but tend to eat only a single species of euphausiid. T. mexicanus grows to twice the length of T. nigrescens and eats proportionally larger euphausiids; however, both fishes eat copepods having the same median size. The frequencies of euphausiid species in the diets of both fishes differ from the frequencies in the environment. The chief differences between the feeding habits of the two lanternfishes are that T. nigrescens, in comparison to its congener, eats a greater variety of organisms during one diurnal feeding period and captures smaller euphausiids. The feeding patterns for each lanternfish species are consistent over distances of hundreds of kilometers and over many years of sampling.

1. 1. Of eight species examined four contained less than 4·3 per cent (fresh wt.) lipid and four at least 14·2 percent. 2. 2. C 30 C 38 wax esters with one and two double bonds were the major lipid in three species with high total lipid; C 36 and C 38 homologs with five and six double bonds were detected in two of these species. 3. 3. The alcohol moieties of the wax esters were largely (74–82%) 1-hexadecanol, and octadecenoic was the predominant (72–76%) fattcy acid. 4. 4. The high was ester content correlates with deeper living and a pattern of daily vertical migration.

The pineal complexes of two deep-sea fishes, Bathylagus wesethi (family Bathylagidae) and Nezumia liolepis (family Macrouridae), were studied with both light and electron microscopy. Receptor and supportive cells were identified in the pineals of both species. The presence of receptor cells suggests that the pineals function in photoreception. Ganglion cells could be identified only in B. wesethi. A dorsal sac and a paraphysis were found in B. wesethi; both structures are absent in N. liolepis. Several trends were found when the results of this study were compared with those of a study on the pineal complex of another deep-sea fish, the myctophid Triphoturus mexicanus (McNulty and Nafpaktitis, 1976). Two of these trends, which are correlated with the vertical distributions of the species studied, suggest an increase in the photosensitivity of the pineals. These are: 1) an increase in the average number of outer segment lamellar membranes per receptor cell, and 2) an increase in the ratio of receptor cells to nerve fibers in the pineal stalks. A functional relationship between the dorsal sac, paraphysis, and pineal central lumen was suggested. The relationship may involve secretory activities.

CONTAMINATION of marine fish by chlorinated hydrocarbons, especially by DDT and its congeners*, could threaten their future or continued utility as a food source if residues accumulate to the point of incipient toxicity on detrimental sublethal effects1. Little is known about the distribution of DDT residues in marine fish beyond listed concentration values for certain species. Most investigations have dealt with concentrations of residues in tissues or large pooled, unsorted samples of commercially caught fish (refs. 3 and 4; the latter covers exclusively marine studies). From this limited information, we know that fish of a single species caught 111 adjacent areas have markedly different contents of residues, probably because of differences in the magnitude of local sources of estuarine or airborne pesticides2–5. This heterogeneity of exposure poses problems for the interpretation of residue data from fish caught in these areas. In an attempt to obtain size-class data about concentrations of residues, relatively free from the effects of pesticide “hot spots”6, Triphoturus mexicanus, a midwater fish from an area relatively remote from areas of pesticide application, was chosen for analysis.

A series of 203 midwater trawl hauls, most of which were discrete-depth samples, was taken at 126 trawling sites along nearly the entire length of the Gulf of California in 1967, 1968, and 1969. The resulting collection of 10,003 adult fishes has been analyzed as a representation of the community of midwater fishes which resides within the Gulf. A total of 39 species from 32 genera and 17 families were taken. In the collection, Triphoturus mexicanus was the dominant form (68%), followed by Vinciguerria lucetia (10.2%), Cyclothone spp. (8.2%), Diogenichthys laternatus (7.2%), and Benthosema panamense (2.8%). The bulk of the midwater community occupied a depth range between 300 and 400 m during daylight hours and from 50 to 100 m at night. The community is composed mainly of tropical forms but its proportional composition is unique to the Gulf. Water mass structure and surface water characteristics are considered as determinants