grenadiers Coryphaenoides (Nematonurus) armatus in the eastern North Pacific Ocean

• Main Authors: I. G. Priede, P. M. Ragley, K. L. Smith
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Diack for help in dcploymcnt and operation of the AU; Pacific; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.1130; http://www.aslo.org/lo/toc/vol_39/issue_2/0279.pdf

The responses of the grenadier fish Coryphaenoidcs (Ncmatonurus) armatus to bait deployed on the sea floor at station M in the North Pacific Ocean (34”50’N, 123”OO’W; 4,100 m deep) in February and October were compared. In February 1990 and 1992, the first fish arrived after an avcragc time of 25 min and stayed an average of 150 min. In October 199 1, the respcctivc times were 15 and 98 min. The faster response in October is correlated with a higher mean swimming speed of 0.0692 m s ’ compared with 0.0262 m s ’ in February. Fish activity was clcvatcd in October following seasonal enrichment to the benthos by downward flux of particulate organic matter from the surface. Grenadier abundance was estimated from arrival times as 325 individuals km l, corresponding to a wet weight biomass of 146 mg m 7 or 10.2 mgC m ‘. Coryphaenoids (Nematonurus) armatus is a ubiquitous demersal scavenger living at depths between 2,200 and 5,400 m in the North Pacific and North Atlantic Oceans (Merrett 1992). Priede ct al. (199 1) found that this spe-cies, with Coryphaenoides (Ncmatonurus) ya-quinae, is the dominant consumer ofbait placed on the abyssal sea floor in the northern hemi-sphere. Baited cameras invariably observed these grenadiers swimming against the current, following an odor plume to locate a food fall (Wilson and Smith 1984). Such experiments have been used as a qualitative means of study-ing the mobile abyssal megafauna for at least two decades (Isaacs and Schwartzlose 1975). Desbruyeres et al. (1985) observed that C. (N.) armatus was present for several tidal cycles-its numbers fluctuating with the tide Priede and Smith (1986) showed that fish could be induced to ingest acoustic transmit-ters placed in baits; to ensure that these fish