Inter- and intra-regional patterns of stable isotopes in Dosidicus gigas beak: biological, geographical and environmental effects

2018 ◽  
Vol 69 (3) ◽  
pp. 464 ◽  
Author(s):  
Bi Lin Liu ◽  
Jing Yuan Lin ◽  
Xin Jun Chen ◽  
Yue Jin ◽  
Jin Tao Wang
Keyword(s):  
Pacific Ocean ◽  
Additive Models ◽  
Trophic Levels ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
Dosidicus Gigas ◽  
The South ◽  
Generalised Additive Model ◽  
South Eastern ◽  
Wide Range

We analysed stable carbon (δ13C) and nitrogen (δ15N) isotopes of 478 Dosidicus gigas specimens collected outside the Ecuadorian, Peruvian and Chilean exclusive economic zones in the south-eastern Pacific Ocean during 2009 to 2013. There were significant spatial differences both in δ13C and δ15N values across regions, with the lowest values off Ecuador and the highest values off Chile. A small intra-regional range of isotope values indicates that squid off Ecuador feed at the same trophic level with similar primary production. In contrast, a large intra-regional range of isotope values suggests that squid off Chile, especially Peru, migrate over a large geographic range and occupy a wide range of trophic levels. A generalised additive model was used to estimate the biological (mantle length and age), geographical (latitude, and distance to the shelf break) and environmental (sea-surface temperature and chlorophyll-a) effects on isotope values. Best fitted generalised additive models explained 54.0% of the variability in δ13C and 93.1% of the variability in δ15N. The yield relationships between isotopes and explanatory variables increase our understanding of D. gigas habitats, movement and feeding ecology in the south-eastern Pacific Ocean.

scholarly journals Discovering sounds in Patagonia, characterizing sei whale (<i>Balaenoptera borealis</i>) downsweeps in the south-eastern Pacific Ocean

2018 ◽  
Author(s):  
Sonia Español-Jiménez ◽  
Paulina A. Bahamonde ◽  
Gustavo Chiang ◽  
Verena Häussermann
Keyword(s):  
Pacific Ocean ◽  
Peak Frequency ◽  
Eastern Pacific ◽  
Absolute Maximum ◽  
Maximum Frequency ◽  
Eastern Pacific Ocean ◽  
The South ◽  
South Eastern ◽  
Average Maximum ◽  
The Absolute

Abstract. Sei whales (Balaenoptera borealis) is the least known whale species. Information on sei whale´s vocalizations in the south-eastern Pacific Ocean and its regional variability are even more scarce than that from other ocean areas. This research presents the first characterization of sei whale sounds recorded in Chile during austral autumn of 2016 and 2017. A total of 41 calls have been attributed to sei whale’s downsweeps. In 2016, calls ranged from an average maximum frequency of 105.3 Hz down to an average minimum 35.6 Hz over 1.6 s with a peak frequency of 65.4 Hz. During 2017, calls ranged from an average maximum frequency of 93.3 Hz down to 42.2 Hz (over 1.6 s) with a peak frequency of 68.3 Hz. The absolute minimum frequency recorded was 30 Hz and the absolute maximum frequency was 129.4 Hz. Calls generally occurred in pairs, but triplets or singles were also registered. These low frequency sounds share characteristics with recordings of sei whales near the Hawaii Islands, but with differences in the maximum frequencies and duration. These calls distinctly differ from sounds previously described for sei whales in the Southern Ocean and are the first documented sei whale calls in the South-eastern Pacific.

New digeneans (Opecoelidae) from hydrothermal vent fishes in the south eastern Pacific Ocean, including one new genus and five new species

Zootaxa ◽  
2014 ◽  
Vol 3768 (1) ◽  
pp. 73 ◽  
Author(s):  
R. A. BRAY ◽  
A. WAESCHENBACH ◽  
P. DYAL ◽  
D. T.J. LITTLEWOOD ◽  
S. MORAND
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Hydrothermal Vent ◽  
New Genus ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
The South ◽  
South Eastern

Spatial genetic structure and demographic inference of the Patagonian squid Doryteuthis gahi in the south-eastern Pacific Ocean

2011 ◽  
Vol 92 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Christian M. Ibáñez ◽  
Juan Argüelles ◽  
Carmen Yamashiro ◽  
Luis Adasme ◽  
Renato Céspedes ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Pacific Ocean ◽  
Spatial Genetic Structure ◽  
Demographic History ◽  
Wide Distribution ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
The South ◽  
South Eastern ◽  
Demographic Inference

Doryteuthis gahi is a small squid species that has a wide distribution in South America. This species is characterized by coastal and benthic spawning, and its ontogenetic vertical migration is associated with upwelling zones, features that may restrict its dispersal potential. It has also been proposed that populations of these neritic squid are structured by the influence of local processes which act as barriers to gene flow. Based on this background, we evaluate the geographical structure of genetic diversity in D. gahi along its distribution in the south-eastern Pacific Ocean. We used 116 COI mtDNA sequences of squid collected from different sites in Peru and Chile and calculated genetic diversity, the population structure index Fst, and performed analysis of spatial molecular variance and exact tests to detect differences among localities. To infer demographic history we carried out tests of neutrality and Bayesian skyline analysis. Although there was little molecular divergence between Peru and Chile, we detected a significant genetic differentiation of D. gahi along its geographical distribution. Squid from Chile showed higher genetic diversity than those of Peru and the results of the demographic inference analysis suggest that the population of Peru is experiencing or experienced in the recent past demographic expansion, a pattern that was not found in Chile. We think that the current genetic patterns are consequences of northward migrations in the glaciation periods and posterior re-colonization of southern Chile in the deglacial period.

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