Stomach Contents of Snow Crab (Chionoecetes opilio, Decapoda, Brachyura) from the Northeast Newfoundland Shelf

Abstract

A sample of about 1000 snow crabs (Chionoecetes opilio) from NAFO (Northwest Atlantic Fisheries Organization) Division 3K (Northeast Newfoundland Shelf), taken by bottom trawl for studies of their stomach contents, indicated that about 12 benthic or demersal prey types occurred in their diet from that area. The most frequently occurring prey types were sabellid polychaetes, crustaceans (shrimp, crabs and smaller crustaceans) and infaunal clams (Macoma calcarea). Shrimps (especially pink shrimp, Pandalus borealis) and fishes (especially capelin, Mallotus villosus) were the most important prey types with respect to their percentage contribution to the total food mass. Brittle stars (Ophiuroidea) were regularly preyed upon by males but were virtually absent from the stomach contents of mature females. Males preyed more heavily upon fish and infaunal prey types (polychaetes and clams) whereas females preyed more heavily on shrimp and readily-accessible epibenthic prey types (gastropods, crabs and sea urchins). Males appeared to be more capable predators than were mature females. Predation on fish was related to predator size for both sexes but was most commonly practiced by males that were larger than the maximum size of mature females. However predation on fish was also more commonly practiced by males than by mature females at comparable sizes. There were no other effects of predator size in the predation by males whereas predation by mature females on clams, shrimp, gastropods, sea urchins, and possibly polychaetes increased with predator size. Cannibalism was most frequently practiced by intermediate-sized crabs and more frequently by females than males. Cannibalism was more common in our study than in others reported to date and may represent an important densitydependent source of mortality that could affect recruitment levels and patterns.

Ecological role of large benthic decapods in marine ecosystems: a review

“…; 5-35%) were more important. Crabs, mostly small Chionoecetes opilio, were also frequently consumed (Squires & Dawe 2003). In Bonne Bay, Newfoundland, large crabs were more likely to scavenge on dead fish (e.g.…”

“…Prey size tends to increase, and species preferences change with the size of the animal (e.g. Stevens et al 1982, Robles et al 1990, SainteMarie & Chabot 2002, Squires & Dawe 2003, Hanson 2009), likely reflecting their changing ability to manipulate larger and better defended organisms as they grow. Large decapods can often overpower the defenses of their prey, for example by crushing mussel shells (Robles et al 1990).…”

“…Jewett & Feder 1982, Wieczorek & Hooper 1995, Squires & Dawe 2003 Their diet may include gastropods, bivalves, chitons, crustaceans, sea urchins, sea stars, polychaetes, algae and occasionally, fish (e.g. Jewett & Feder 1982, Stevens et al 1982, Elner & Campbell 1987, Lawton 1987, Robles 1987, Wieczorek & Hoo -per 1995, Cox et al 1997, Squires & Dawe 2003, Hanson 2009). Other decapods and even conspecifics are also consumed, including their moulted exoskeletons (e.g.…”

Community structure of epibenthic megafauna in the Chukchi Sea

“…However, we suspect this difference reflects weaker pelagic-benthic coupling for epibenthic megafauna than for macrofauna (Grebmeier et al 2006a). Coupling could be weak due to: (1) the higher mobility of many biomass-rich epifaunal organisms obscuring relationships of biomass to food availability at any given location (although sessile epifauna alone were not correlated to these variables either) or (2) the predatory, scavenging, or opportunistic feeding types of many of the biomassdominating species such as Ophiura sarsi (Warner 1982), Chionoecetes opilio , Squires & Dawe 2003 and sea stars (Jangoux & Lawrence 1982), again obscuring pelagic-benthic coupling at any given station. In contrast, several of the biomass-dominating macrofaunal benthic species such as ampeliscid amphipods, macrofaunal clams and various polychaetes (Grebmeier et al 1989, Feder et al 2007, Sirenko & Gagaev 2007 are sessile suspension or filter feeders, directly exploiting fresh organic carbon from the water column (Iken et al in press).…”

Differential regulatory roles of crustacean predators in a sub-arctic, soft-sediment system

“…Robichaud et al 1991, Worm & Myers 2003, and the interaction of these factors. Snow crab and other decapod crustaceans primarily feed on bottom dwelling organisms such as polychaetes, clams, and peracarid crustaceans (Scarrat & Lowe 1972, Brêthes et al 1984, Stehlik 1993, Squires & Dawe 2003. As cod and other major fish predators are largely pelagic, the current dominance of decapod crustaceans suggests that the western North Atlantic shelf ecosystem has experienced a switch in predator regimes from primarily pelagic to bottom-feeding predators.…”