Feeding habits of neon flying squid Ommastrephes bartramii in the transitional region of the central North Pacific

Abstract

ABSTRACT:We examined the feeding habits of the neon flying squid Ommastrephes bartramii from late spring to mid-summer in relation to its northward migration in the transitional waters of the central North Pacific. The winter-spring cohort (ca. 15 to 25 cm in May and 20 to 35 cm in July) and the autumn cohort (ca. 30 to 45 cm in May and 35 to 50 cm in July) were identified by their dorsal mantle lengths. In May and July, the winter-spring cohort was distributed only in the transition zone (TZ) south of the subarctic boundary. This cohort preyed primarily on crustaceans such as euphausiids and amphipods in May, but in July, their primary prey shifted to the sternoptychid fish Maurolicus imperatorius. In May, the larger-sized autumn cohort was also distributed only in the TZ, but in July, these individuals migrated to the transitional domain (TD) north of the subarctic boundary. The main prey of the autumn cohort were micronektonic animals that dominated the TZ in May: the transitionalwater myctophid Symbolophorus californiensis, and 2 subtropical myctophids, Ceratoscopelus warmingi and Electrona risso. Secondary important prey items included the transitional-water squid Onychoteuthis borealijaponica and subarctic gonatid squids such as Gonatus berryi and Berryteuthis anonychus. In July, the main prey species in the TD were S. californiensis and O. borealijaponica, both of which also migrated from the TZ into the TD, crossing the subarctic boundary in summer. We estimated the feeding impact of the autumn squid cohort on myctophids in the TD during summer.

Escaping the oligotrophic gyre? The year-round movements, foraging behaviour and habitat preferences of Murphy’s petrels

“…Additionally, birds appear to use the NPTZ, which spans the Subarctic and Subtropical Frontal Zones, and is an important foraging and migration habitat for many species due to aggregations of mesopelagic prey (Robinson et al 2012). For example, DVM squid seasonally migrate from spawning areas in the subtropics to the Subarctic Frontal Zone to feed on myctophid fishes (Watanabe et al 2004, Ichii et al 2009). …”

Relationships between otolith size and fish size in some mesopelagic and bathypelagic species from the Mediterranean Sea (Strait of Messina, Italy)

“…Their importance is also documented in stomach analysis of cephalopods that use their beaks to chop preys (e.g. Watanabe et al, 2004), making them identifiable only by otolith determination.…”

“…Moreover, several other predators, such as marine mammals (Hassani et al, 1997;Pauly et al, 1998;Springer et al, 1999;Dolar et al, 2003;Ohizumi et al, 2003), seabirds (Springer et al, 1999) and cephalopods (Marabello et al, 1996;Watanabe et al, 2004), rely on these food resources.…”

Relationships between Fish and Otolith Size of the Blackspot Snapper <i>Lutjanus ehrenbergii</i> (Peters, 1869) Collected from the Coast of Muscat City, Sea of Oman

“…The predator consumption rates, biomass of the prey consumed, and selectivity of a predator towards a specific size class of prey are sets of biological and ecological information that usually used in the feeding studies. In getting such information, the original size of the ingested prey needs to be estimated (Granadeiro and Silva, 2000;Watanabe et al, 2004;Battaglia et al, 2010). Otolith measurements are usually used to rebuild the prey body size by linking the correlation between otolith length and fish size (Templemann and Squires, 1956;Echeveria, 1987;Panfili et al, 2002).…”