Skip to main content

Effects of ontogeny, temperature, and light on vertical movements of larval Pacific cod (Gadus macrocephalus)

Buy Article:

$51.00 plus tax (Refund Policy)

Abstract:

Abstract

The role of behavior, especially vertical migration, is recognized as a critical component of realistic models of larval fish dispersion. Unfortunately, our understanding of these behaviors lags well behind our ability to construct three-dimensional flow-field models. Previous field studies of vertical behavior of larval Pacific cod (Gadus macrocephalus) were limited to small, preflexion stages (≤11 mm SL) in a narrow range of thermal conditions. To develop a more complete picture of larval behavior, we examined the effects of ontogeny, temperature, and light on vertical responses of larval Pacific cod in experimental columns. While eggs were strictly demersal, yolk-sac larvae displayed a strong surface orientation as early as 1 day post hatch (∼ 5 mm SL). Consistent with field observations, small preflexion larvae (<10 mm SL) showed no response to varying light levels. However, there was a direct effect of temperature on larval behavior: Pacific cod larvae exhibited a stronger surface orientation at 4°C than at 8°C. The behavior of larger, postflexion larvae (>15 mm SL) in experimental columns was consistent with a diel vertical migration and independent of water temperature: fish were more widely distributed in the column, and median positions were consistently deeper at higher light levels. These laboratory observations are combined with observations from discrete-depth (MOCNESS) sampling in the Gulf of Alaska to characterize the vertical distribution of larval Pacific cod and contrast ontogenetic patterns with walleye pollock (Theragra chalcogramma). The vertical movements of larval Pacific cod described here will be applied in the development of dispersal projections from Gulf of Alaska spawning grounds.

Keywords: Gulf of Alaska; Pacific cod Gadus macrocephalus; diel vertical migration; larval behavior; larval transport; vertical distribution

Document Type: Research Article

DOI: https://doi.org/10.1111/j.1365-2419.2009.00512.x

Affiliations: 1: NOAA/NMFS Alaska Fisheries Science Center, Recruitment Processes Program, Bldg 4, 7600 Sand Point Way NE, Seattle, WA 98115-0070 USA 2: NOAA-NMFS Alaska Fisheries Science Center, Fisheries Behavioral Ecology Program, Hatfield Marine Science Center, 2030 S. Marine Science Dr., Newport, OR 97365 USA

Publication date: 2009-09-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more