Trophic interactions between key predatory fishes and crustaceans: comparison of two Northwest Atlantic systems during a period of ecosystem change

Marine Ecology Progress Series

Denis Chabot¹  Darrell Mullowney¹  Don Stansbury¹  Mariano Koen-Alonso¹  Earl Dawe¹ 

关键词: Canadian Atlantic;    Predation;    Atlantic cod;    Greenland halibut;    Northern shrimp;    Snow crab;   

DOI  :  10.3354/meps10136

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: This study shows that a sharp ecosystem transition in dominant communities during the early 1990s, from finfish to crustaceans, was common to the 2 northernmost Northwest Atlantic ecosystems, the Newfoundland−Labrador shelf (NL) and the northern Gulf of St. Lawrence (nGSL). Fishery and survey data show that populations of Atlantic cod Gadus morhua, typical of most finfish species, collapsed during the late 1980s to early 1990s in both systems, while Greenland halibut Reinhardtius hippoglossoides populations changed little. Biomass of northern shrimp Pandalus borealis increased following the collapse of cod in both systems, likely due, at least in part, to release of predation pressure. Predation appeared to have relatively little effect on biomass of snow crab Chionoecetes opilio. Shrimp replaced capelin as the principal prey in the diet of NL cod and nGSL Greenland halibut in the mid-1990s. The contribution of shrimp to the predator diets was generally highest when neither capelin nor other suitable prey (fish or squid) were available. We conclude that the NL and nGSL ecosystems are similar in form and function, differing from Canadian Atlantic ecosystems further south. The implications of a change in predominant forage species from capelin to shrimp in these systems are unknown, but could conveivably include changes in the pathway and efficiency of energy flow.

【 授权许可】

Unknown