scholarly journals Tracing migratory movements of breeding North Pacific humpback whales using stable isotope analysis

2009 ◽  
Vol 393 ◽  
pp. 173-183 ◽  
Author(s):  
BH Witteveen ◽  
GAJ Worthy ◽  
JD Roth
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
North Pacific ◽  
Isotope Analysis ◽  
Humpback Whales ◽  
Migratory Movements

The diets of humpback whales (Megaptera novaeangliae) on the shelf and oceanic feeding grounds in the western North Pacific inferred from stable isotope analysis

2012 ◽  
Vol 29 (3) ◽  
pp. E253-E265 ◽  
Author(s):  
Olga A. Filatova ◽  
Briana H. Witteveen ◽  
Anton A. Goncharov ◽  
Alexei V. Tiunov ◽  
Maria I. Goncharova ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
North Pacific ◽  
Western North Pacific ◽  
Isotope Analysis ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Feeding Grounds

scholarly journals Feeding Ecology of Three Euphausiid Species in the North Pacific Ocean Inferred From 18S V9 Metabarcoding and Stable Isotope Analysis

2021 ◽  
Vol 8 ◽  
Author(s):  
Fanyu Zhou ◽  
Junya Hirai ◽  
Koji Hamasaki ◽  
Sachiko Horii ◽  
Atsushi Tsuda
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Feeding Ecology ◽  
North Pacific ◽  
Prey Availability ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Gut Contents ◽  
North Pacific Subtropical Gyre

Euphausiids are abundant micronekton and important links between higher and lower trophic levels in marine ecosystems; however, their detailed diets cannot be fully understood by conventional microscopy, especially in subtropical areas. Here, we report the euphausiid community structure in the California Current (CC) area and the eastern/western North Pacific subtropical gyre (ESG and WSG) and detail the feeding ecology of the dominant species (Euphausia pacifica, E. brevis, and E. hemigibba) in each region using a combined approach of gut content analysis via 18S V9 metabarcoding and stable carbon and nitrogen isotope analysis. A pronounced omnivorous feeding of all studied euphausiid species was supported by both methods: phytoplanktonic taxonomic groups (Dinophyta, Stramenopiles, and Archaeplastida), Copepoda, and Hydrozoa were detected in the gut contents; all the three euphausiid species displayed an intermediate trophic position between the net plankton (0.2–1.0 mm) and the myctophid fish (15.2–85.5 mm). However, Hydrozoa found in euphausiid gut contents likely derived from a potential cod-end feeding, based on isotope analysis. E. pacifica in the CC province ingested more autotrophic prey, including pelagophyte and green algae, due to a greater abundance of Stramenopiles and Archaeplastida in shallow layers of CC water. On the other hand, non-autotrophic prey such as mixotrophic Kareniaceae dinoflagellates, Pontellidae and Clausocalanidae copepods, and Sphaerozoidae rhizarian contributed more to the diets of E. brevis and E. hemigibba because of a lower chlorophyll a concentration or potentially a scarcity of autotrophic prey availability in ESG and WSG. The feeding patterns of dominant euphausiid species conducting filter feeding were thus largely determined by phytoplankton prey availability in the environments. Dietary difference across three species was also indicated by stable isotope analysis, with a lower mean trophic level of E. pacifica (2.32) than E. brevis (2.48) and E. hemigibba (2.57). These results verify direct trophic interactions between euphausiids and primary production and suggest that the omnivorous feeding habit is a favorable character for dominant Euphausia species.

Stable isotope analysis reveals that humpback whales (Megaptera novaeangliae) primarily consume capelin (Mallotus villosus) in coastal Newfoundland, Canada

2021 ◽  
Author(s):  
Kelsey Johnson ◽  
Gail Davoren
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Prey Type ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Mallotus Villosus ◽  
Δ13c And Δ15n ◽  
Capelin Mallotus Villosus

On the Newfoundland, Canada foraging ground, humpback whales (Megaptera novaeangliae (Borowski, 1781)) are found associated with a dominant forage fish species, capelin (Mallotus villosus (Müller, 1776), that experienced a population collapse in the early 1990s and has not recovered. Our primary goal was to reconstruct dietary proportions of humpback whales on their summer foraging grounds off the northeastern Newfoundland coast during July-August, 2016 and 2017 using a Bayesian stable isotope mixing model (MixSiar). Modelled dietary proportions were similar in both years, with capelin comprising ~90% of the diet. However, both δ13C and δ15N in humpback whale skin differed significantly between years, resulting in minimal dietary niche overlap (9%). Lipid-extracted and nonlipid-extracted skin samples were used to develop a lipid normalization equation: ∆13C = – 3.184 + 1.011(C:N). Overall, findings suggest that capelin is the primary prey type of humpback whales in coastal Newfoundland, despite the continued collapsed state of the capelin population. Findings also reiterate that dietary reconstruction from stable isotope analysis of cetacean skin can be misinterpreted without concurrently sampled isotopic ratios of potential prey types.

Evidence of two subaggregations of humpback whales on the Kodiak, Alaska, feeding ground revealed from stable isotope analysis

2015 ◽  
Vol 31 (4) ◽  
pp. 1378-1400 ◽  
Author(s):  
Dana L. Wright ◽  
Briana Witteveen ◽  
Kate Wynne ◽  
Larissa Horstmann‐Dehn
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Humpback Whales ◽  
Feeding Ground

Pan-North Pacific comparison of long-term variation in Neocalanus copepods based on stable isotope analysis

2012 ◽  
Vol 97-100 ◽  
pp. 63-75 ◽  
Author(s):  
Sanae Chiba ◽  
Hiroya Sugisaki ◽  
Akira Kuwata ◽  
Kazuaki Tadokoro ◽  
Toru Kobari ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
North Pacific ◽  
Isotope Analysis ◽  
Term Variation

Stable isotope analysis and satellite tracking reveal interspecific resource partitioning of nonbreeding albatrosses off Alaska

2010 ◽  
Vol 88 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Robert M. Suryan ◽  
Karen N. Fischer
Keyword(s):  
Stable Isotope ◽  
Carbon Isotope ◽  
Stable Isotope Analysis ◽  
North Pacific ◽  
Isotope Analysis ◽  
Isotope Ratios ◽  
Satellite Tracking ◽  
Trophic Levels ◽  
Carbon Isotope Ratios ◽  
Nonbreeding Season

Albatrosses (Diomedeidae) are the most threatened family of birds globally. The three North Pacific species ( Phoebastria Reichenbach, 1853) are listed as either endangered or vulnerable, with the population of Short-tailed Albatross ( Phoebastria albatrus (Pallas, 1769)) less than 1% of its historical size. All North Pacific albatross species do not currently breed sympatrically, yet they do co-occur at-sea during the nonbreeding season. We incorporated stable isotope analysis with the first simultaneous satellite-tracking study of all three North Pacific albatross species while sympatric on summer (nonbreeding season) foraging grounds off Alaska. Carbon isotope ratios and tracking data identify differences in primary foraging domains of continental shelf and slope waters for Short-tailed Albatrosses and Black-footed Albatrosses ( Phoebastria nigripes (Audubon, 1839)) versus oceanic waters for Laysan Albatrosses ( Phoebastria immutabilis (Rothschild, 1893)). Short-tailed and Black-footed albatrosses also fed at higher trophic levels than Laysan Albatrosses. The relative trophic position of Black-footed and Laysan albatrosses, however, appears to differ between nonbreeding and breeding seasons. Spatial segregation also occurred at a broader geographic scale, with Short-tailed Albatrosses ranging more north into the Bering Sea than Black-footed Albatrosses, which ranged more to the southeast, and Laysan Albatrosses more to the southwest. Differences in carbon isotope ratios among North Pacific albatross species during the nonbreeding season likely reflect the relative proportion of neritic (more carbon enriched) versus oceanic (carbon depleted) derived nutrients, and possible differential use of fishery discards, rather than latitudinal differences in distribution.

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