Seasonal occurrence and vertical distribution of larval and juvenile northern smoothtongue, Leuroglossus schmidti (Pisces, Bathylagidae), in the western subarctic Pacific

2020 ◽  
Vol 100 (6) ◽  
pp. 969-977
Author(s):  
Minoru Kitamura ◽  
Naofumi Murata
Keyword(s):  
Vertical Distribution ◽  
Larval Fish ◽  
North Pacific Ocean ◽  
Seasonal Occurrence ◽  
Fish Ecology ◽  
Mesopelagic Fish ◽  
Subarctic Pacific ◽  
Larval Recruitment ◽  
Western Subarctic Pacific ◽  
Western Subarctic North Pacific

AbstractWe investigated the seasonal occurrence and vertical distribution/migration of larval and juvenile northern smoothtongue, Leuroglossus schmidti (Pisces, Bathylagidae), in oceanic areas of the western subarctic Pacific. This species was the most abundant larval fish and one of the most abundant juvenile/adult fish at the study site. Larval recruitment of this species occurred in early March to mid-October. Larvae were found, however, throughout all seasons, suggesting that some had overwintered. The highest abundance (5.8 individuals m–2) of larvae was in summer. During summer and autumn, hatching mainly occurred at 100–150-m depth and larvae migrated toward the surface with growth. Once larvae reached about 20 mm in length, they moved below 100 m, and larger larvae (over 24 mm) exhibited diel vertical migration. The abundance of juveniles integrated through the water column was relatively constant (0.3 individuals m–2) throughout the study period. They were collected from below 300 m during the day, and part of the population (13–38%) swam into the epipelagic layer at night. The information on early stages of L. schmidti presented here provides a basis for future investigations of mesopelagic fish ecology in oceanic areas of the western subarctic North Pacific Ocean.

Mesozooplankton responses to iron-fertilization in the western subarctic Pacific (SEEDS2001)

2005 ◽  
Vol 64 (2-4) ◽  
pp. 237-251 ◽  
Author(s):  
Atsushi Tsuda ◽  
Hiroaki Saito ◽  
Jun Nishioka ◽  
Tsuneo Ono
Keyword(s):  
Subarctic Pacific ◽  
Western Subarctic Pacific ◽  
Iron Fertilization

Laboratory observations on early development of the oncaeid copepod Triconia canadensis from the mesopelagic zone of the western subarctic Pacific

2007 ◽  
Vol 87 (2) ◽  
pp. 479-482 ◽  
Author(s):  
Yuichiro Nishibe ◽  
Tsutomu Ikeda
Keyword(s):  
Lipid Droplets ◽  
Development Time ◽  
Hatching Success ◽  
Egg Development ◽  
Egg Hatching ◽  
Subarctic Pacific ◽  
Western Subarctic Pacific ◽  
Mesopelagic Zone ◽  
Life Cycle Strategy

Egg development time and hatching success were determined for the oncaeid copepod, Triconia canadensis, from the mesopelagic zone of the western subarctic Pacific. The egg development time was estimated to be 74.7–84.5 days at in situ temperature (3°C), which is much longer than those reported previously on the other oncaeid copepods even if the differences in experimental temperatures are taken into account. The egg hatching success varied between 50 and 100%, with a grand mean of 88%. The newly hatched nauplii of T. canadensis were elongate ellipsoid in shape, and had many large-sized lipid droplets in their body. Possible adaptive significance of apparent longer egg developmment time of T. canadensis is discussed in the light of their life cycle strategy.

scholarly journals Coastal winds drive a recruitment mechanism for estuarine fisheries

2020 ◽  
Author(s):  
Hayden T. Schilling ◽  
Charles Hinchliffe ◽  
Jonathan P. Gillson ◽  
Anthony Miskiewicz ◽  
Iain M. Suthers
Keyword(s):  
Larval Fish ◽  
Future Research ◽  
Larval Abundance ◽  
Spawning Period ◽  
Onshore Wind ◽  
Larval Recruitment ◽  
Australian Region ◽  
Coastal Winds ◽  
Key Driver ◽  
Catch Rates

AbstractCoastal winds transport larval fish onshore or offshore which may contribute to estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we show that larval abundance of coastally spawned species increased with weak to moderate upwelling favourable winds 14 days prior to sampling, reflecting increased nutrient and plankton availability for larval fish. A strong decline in larval abundance was observed following strong upwelling favourable winds while abundance increased with onshore (downwelling favourable) winds, in relation to offshore and onshore wind-driven transport. Subsequently, we show that effects of wind during the spawning period can be detected in lagged estuarine commercial fisheries catch rates of coastally spawned species (lagged by 2 – 8 years depending on species’ growth rates), representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may reduce larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the east Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds. As global winds are changing, it is important to investigate if this mechanism is applicable to other regions around the world where coastal winds are a key driver of upwelling.

Vertical distribution of mesozooplankton and ichthyoplankton communities in the South-western Atlantic Ocean (23°14′1″S 40°42′19″W)

2018 ◽  
Vol 99 (1) ◽  
pp. 51-65
Author(s):  
Ana C. T. Bonecker ◽  
Cristina De O. Dias ◽  
Marcia S. De Castro ◽  
Pedro F. De Carvalho ◽  
Adriana V. Araujo ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Vertical Distribution ◽  
Heterotrophic Bacteria ◽  
Larval Fish ◽  
Nutrient Concentrations ◽  
Intermediate Water ◽  
The South ◽  
Night Time ◽  
Western Atlantic ◽  
Western Atlantic Ocean

A study was conducted over eight consecutive days in February 2010 in which daily variations in the vertical distributions of heterotrophic bacteria, mesozooplankton and ichthyoplankton at 1–1200 m in the South-western Atlantic Ocean were investigated. Diurnal and nocturnal samples were collected at an oceanographic station at four regional depths: Tropical Water (TW) (1 m), South Atlantic Central Water (SACW) (250 m), Antarctic Intermediate Water (AAIW) (800 m) and Upper Circumpolar Deep Water (UCDW) (1200 m). Bacterial, mesozooplankton and larval fish densities significantly differed between sample depths but not between sampling tow times. In total, 154 zooplankton species and 18 larval fish species were identified. The highest number of taxa was obtained from the night-time TW trawls. This depth zone had the highest densities of mesozooplankton, larval fish and bacterioplankton (auto and heterotrophic), associated with the highest temperature and salinity and the lowest inorganic nutrient concentrations. Two sample groups were identified based on their mesozooplankton and larval fish compositions: night-time TW and other water masses (daytime TW, SACW, AAIW and UCDW). Thirty-two indicator species were detected in night-time TW. The copepod Nullosetigera impar was, to the best of our knowledge, identified for the first time on the Brazilian coast. Our results showed significant variability in the abundance and vertical distribution of mesozooplankton, bacterioplankton and larval fish along the water column in an oceanic area. We have provided new data and insights on the composition and vertical distribution of mesozooplankton, larval fish and bacterioplankton in deep waters in the South-western Atlantic Ocean.

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