Olsen, 1990; Nunnallee(2)) have demonstrated that gadoids may dive in response to perceived disturbance from vessels and/or trawls.
The observations of Engas and Godo (1989b) regarding the greater degree to which larger gadoids are herded into the path of a bottom trawl are probably also applicable in the pelagic zone; one might also expect greater escapement of small fish through the rope wings of the midwater trawl.
Different authors have reported that the liver is the main deposit of lipids for gadoids
and have considered this organ as the main source of energy for reproduction (Lambert and Dutil, 1997; Alonso-Fernandez, 2011).
Much of the work to date on reproductive potential and stock assessments comes from investigations on gadoids
, pleuronectids, and other high-latitude species that typically have determinate fecundity patterns (Trippel, 1999; Murawski et al.
Factors affecting recruitment of selected gadoids
in the northeast Pacific and east Bering Sea.
2001) examined the timing of the PDO and ENSO and correlated changes in both with recruitment success in groups such as flatfish and gadoids
, but further study is needed to confirm their findings.
Effects of trawl sampling variability on precision of acoustic abundance estimates of gadoids
from the Barents Sea and the Gulf of Alaska.
Survival of gadoids
that escape from a demersal trawl.
Examples include dramatic fluctuations in gadoids
(Sirabella et al.
Figure 11 shows how catches of redfish and gadoids
on vertical longlines compare with the results from the acoustic surveys.
Capelin were sampled using an international young gadoids
pelagic trawl (IYGPT) mid-water-trawl towed in a single oblique haul from the surface to a 100-m depth.
(primarily walleye pollock [Theragra chalcogramma] and Pacific cod [Gadus macrocephalus] appear to have little or no herding response to the 83-112 Eastern trawl (Somerton, 2004) and rarely pass under the footrope (Somerton, unpubl, data).
Nocturnal vertical migration behavior has been described for gadoids
such as hake and cod and is considered responsible for the reduction of trawl catches of these fish at night (Beamish, 1966; Bowman and Bowman, 1980).