Title

Horizontal and Vertical Distribution of Mesopelagic Fishes with special reference to Vinciguerria lucetia (Phosichthyidae:Pisces) in the Humboldt Current Region Off Peru

Event Name/Location

EOS Trans. AGU Ocean Sciences Meeting, Honolulu, Hawaii, February 20-24, 2006

Document Type

Poster

Publication Date

2-2006

Keywords

Mesopelagic fishes, (Vinciguerria lucetia), Humboldt current, Peru, vertical and horizontal distribution, Backscattering energy

Abstract

The horizontal and vertical distribution of adult mesopelagic fishes is described from acoustic-trawls sampling over the full-depth of 500 m at 169 stations on a longitudinal transect between 50 to 200 nautical miles crossing the Humboldt Current off Peru coast (03°45'S, 81°76'W and 18°23'S, 71°13'W) during austral spring (october-november) of 2001, 2002 and 2003. A total of 2952 kg of fishes were collected and included 28 species belonging to 23 genera. The mesopelagic community is dominated by the fish families Phosichthyidae (Vinciguerria lucetia ), Myctophidae (Diogenichthys laternatus and Lampanyctus idostigma) and Bathylagidae (Leuroglossus urotranus), corresponding respectively 84.48 %, 7.19 %, 2.18 % and 1.06 % of the total abundance. Based on horizontal distribution patterns these species were categorized into three groups, i.e. Humboldt north-central group (Leuroglossus urotranus, Nemichthys fronto and Scopelarchoides nicholsi ), Humboldt south group (Hygophum reinhardti, Myctophum nitidulum, Paralepis sp and Scopeloberyx sp.)and Pan-Humboldt group (Vinciguerria lucetia, Diogenichthys laternatus, Lampanyctus(Nannobrachium) idostigma, L. omostigma, M. aurolaternatum, Triphoturus oculeus, Melanolagus berycoides, Leuroglossus stilbius, Argyropelecus affinis, Sternoptyx obscura, Melamphaes sp., Stomias sp., Scopelosaurus sp). Night-time vertical distribution was characterized by single abundance peak in the upper 50 m. Day-time patterns showed 3 peaks of abundance, an upper abundance peak, occurring in the upper 100 m, a midwater abundance peak, over a wider depth range (200-400 m), coinciding with oxygen mimimum zone and a near-bottom abundance peak, occurring between 400-500 m. (Vinciguerria lucetia ) was dominant in upper and midwater peaks while myctophids, other planctivores and piscivorous fishes were distributed in the midwater and deeper peaks. Backscattered energy (Sa) were ubiquitous in the region. Maximum Sa was mainly located between 11 and 18S during day-night time. (Vinciguerria lucetia ) is significant in the oceanic pelagic ecosystem as a major component of fish biomass in deep scattering layer in the Humboldt Current region off Peru and probably of transitional waters in the southeastern Pacific. Keywords: Mesopelagic fishes, (Vinciguerria lucetia) , Humboldt current, Peru, vertical and horizontal distribution, Backscattering energy

Comments

Eos Trans. AGU 87 (36)

Additional Comments

Identifier OS45Q-01