scholarly journals Feeding Habits of the Blue Shark (Prionace glauca) in the Northwestern Pacific Based on Stomach Contents and Stable Isotope Ratios

2018 ◽  
Vol 72 (1) ◽  
pp. 21-39 ◽  
Author(s):  
Yuki Fujinami ◽  
Sayaka Nakatsuka ◽  
Seiji Ohshimo
2020 ◽  
Vol 84 (2) ◽  
Author(s):  
Andrey Soares ◽  
Alex Souza Lira ◽  
Júlio Guazzelli Gonzalez ◽  
Leandro Nolé Eduardo ◽  
Flávia Lucena-Frédou ◽  
...  

This study provides information about the feeding habits, population aspects and spatial distribution of the spot­ted goatfish, Pseudupeneus maculatus, along the coast of the tropical Brazilian continental shelf. Distribution patterns are described using length frequencies and catch rates. Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N), along with stomach contents, were analysed to determine the diet of the spotted goatfish. Multivariate analysis and numerical indicators of the diet, such as numerical frequency, frequency of occurrence and weight percentage, were computed to evaluate the diet composition. The mean trophic position was defined using both stable isotope ratios and stomach content analysis. The length at first maturity for the species was determined as 13.7 cm. A slight pattern in size distribution was observed, with mean size increasing with depth along the shelf. The diet was mainly composed of crustaceans, teleosts and Polychaeta. No clear dietary difference was found between habitat types, water depth or latitude. Both trophic positions estimated by stable isotopes and stomach contents analysis ranged between levels 3 and 4. P. Maculatus was found to be feeding on many rare and infrequent prey items, classifying it as a generalist zoobenthivorous predator, probably due to its efficient search strategy.


Author(s):  
Unai Markaida ◽  
Oscar Sosa-Nishizaki

Stomach contents of 893 blue shark (Prionace glauca) caught off Ensenada, Todos Santos Bay, Baja California, from 1995 to 1997 were analysed. 614 had identifiable food remains. A large variety of pelagic cephalopods occurred in 55.5% of all stomachs and accounted for 46.2% of all prey and 84% by estimated weight of stomach contents. The most abundant (17%) and frequent (32%) was Histioteuthis heteropsis and the most important by estimated weight (22%) was ‘Gonatus californiensis’. Argonauta spp. and Vampyroteuthis infernalis were also abundant prey. A pair of beaks of giant squid Architeuthis sp. constitutes the first record for Mexican waters. Feeding habits and the probability of scavenging on mesopelagic cephalopods is discussed. The single most abundant prey was the pelagic, red crab Pleuroncodes planipes (41.7%). Other prey included teleost fish, amniotes and floating items. Diet varied greatly between months with no clear seasonal pattern. Tiny diet differences due to shark size or sex were inconclusive. A thorough review of studies on blue sharks stomach contents analysis is given. Blue shark feed on a large variety of passive pelagic prey, mainly mesopelagic cephalopods, that could be preyed upon as well as scavenged. Depletion of this predator due to overfishing may be leading to unknown cascading top-down effects in the mesopelagic realm.


2000 ◽  
Vol 36 (3) ◽  
pp. 259-272 ◽  
Author(s):  
I. Tayasu ◽  
F. Hyodo ◽  
Y. Takematsu ◽  
A. Sugimoto ◽  
T. Inoue ◽  
...  

2018 ◽  
Vol 75 (6) ◽  
pp. 977-986 ◽  
Author(s):  
Ana Carolina Pizzochero ◽  
Loïc N. Michel ◽  
Simon R. Chenery ◽  
Ian D. McCarthy ◽  
Marcelo Vianna ◽  
...  

The whitemouth croaker, Micropogonias furnieri, is a long-lived fish of high commercial importance in the western Atlantic Ocean. Here, we used stable isotope ratios of carbon, sulfur, and nitrogen and isotopic niche metrics (SIBER) to study feeding habits and track habitat use by whitemouth croakers in Guanabara Bay, an estuary in Rio de Janeiro state, Brazil. Our results highlighted size-related habitat segregation, with small juvenile fishes (<30 cm) residing mostly inside estuaries and large adult fishes (>60 cm) feeding mainly in Continental Shelf waters. Medium adult fishes (30–60 cm) appear to feed in multiple coastal and Continental Shelf habitats. Moreover, their feeding ecology showed strong temporal differences, linked with seasonal and, to a lesser extent, interannual variation in oceanographic features of the ecosystem in which they live. Overall, these differences in ecological features suggest that (1) adult and juvenile whitemouth croakers should be treated as different components of the food web and (2) the conservation of these habitats should be prioritized to better manage and sustain the coastal fisheries in Guanabara Bay.


Author(s):  
Y Fujinami ◽  
K Shiozaki ◽  
Y Hiraoka ◽  
Y Semba ◽  
S Ohshimo ◽  
...  

Author(s):  
Sosuke Otani ◽  
Sosuke Otani ◽  
Akira Umehara ◽  
Akira Umehara ◽  
Haruka Miyagawa ◽  
...  

Fish yields of Ruditapes philippinarum have been decreased and the resources have not yet recovered. It needs to clarify food sources of R. philippinarum, and relationship between primary and secondary production of it. The purpose on this study is to reveal transfer efficiency from primary producers to R. philippinarum and food sources of R. philippinarum. The field investigation was carried out to quantify biomass of R. philippinarum and primary producers on intertidal sand flat at Zigozen beach in Hiroshima Bay, Japan. In particular, photosynthetic rates of primary producers such as Zostera marina, Ulva sp. and microphytobenthos were determined in laboratory experiments. The carbon and nitrogen stable isotope ratios for R. philippinarum and 8 potential food sources (microphytobenthos, MPOM etc) growing in the tidal flat were also measured. In summer 2015, the primary productions of Z. marina, Ulva sp. and microphytobenthos were estimated to be 70.4 kgC/day, 43.4 kgC/day and 2.2 kgC/day, respectively. Secondary production of R. philippinarum was 0.4 kgC/day. Contribution of microphytobenthos to R. philippinarum as food source was 56-76% on the basis of those carbon and nitrogen stable isotope ratios. Transfer efficiency from microphytobenthos to R. philippinarum was estimated to be 10-14%. It was suggested that microphytobenthos might sustain the high secondary production of R. philippinarum, though the primary production of microphytobenthos was about 1/10 compared to other algae.


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