|
|||||||
|
Horseneck Gaper
Tresus capax
In-depth Information Regarding this Species
Alternate Common Names
Gaper Clams (Hensleigh and Carter 2000)
Range
Highest abundance in Coos and Siuslaw Bays, Oregon (Emmett et al. 1991)
Habitat
N/A
Substrate
Shell fragments, dense sand, silty sand, or gravel/sand (Bourne and Smith 1972b, Wendell et al. 1976, and Cheney and Mumford 1986 all in Emmett et al. 1991)
Greatest concentration in silty sand with eel grass (Humbolt Bay) (Wendell 1973 in Emmett et al. 1991)
Depth range (meters)
N/A
Behavior
Burrow about 25–50 cm into substrate (Cheney and Mumford 1986, Wolotira et al. 1989 both in Emmett et al. 1991)
Burrow deeper in mud and sand versus clay substrate (Oceanographic Institute of Washington 1981 in Emmett et al. 1991)
General Temperature Range (°C)
2–20 (adults and juveniles) (Bernard 1983a in Emmett et al. 1991)
13 (optimum for growth)
11–18 (normal range) (Bernard 1983b in Emmett et al. 1991)
General Salinity Range (ppt)
Adults and juveniles polyhaline–euhaline (Bernard 1983a in Emmett et al. 1991)
28 (optimum)
26–31(normal range) (Bernard 1983b in Emmett et al. 1991)
Maximum Overall Recorded Size (cm)
N/A
Maximum Recorded Size for Males (cm)
N/A
Maximum Recorded Size for Females (cm)
N/A
Average Maximum Overall Length (cm)
25.4 (Emmett et al. 1991)
Average Maximum Overall Length for Males (cm)
N/A
Average Maximum Overall Length for Females (cm)
N/A
Average Maximum weight (kg)
N/A
Average Maximum weight for Males (cm)
N/A
Average Maximum weight for Females (cm)
N/A
Length When Harvested (cm)
N/A
Weight When Harvested (kg)
N/A
Overall Length to Age Ratio (cm/age in years)
N/A
Male Length to Age Ratio (cm/age in years)
N/A
Female Length to Age Ratio (cm/age in years)
N/A
Overall Maximum Age (years)
16 (Emmett et al. 1991)
Oldest individuals found off Oregon are 10–12 years old (Hancock et al. 1979 in Emmett et al. 1991)
Maximum Age for Males (years)
N/A
Maximum Age for Females (years)
N/A
Age when Harvested (years)
N/A
Overall Growth Rate
4–7 year olds grow faster in subtidal versus intertidal zones off Oregon (Hancock et al. 1979 in Emmett et al. 1991)
Male Growth Rate
N/A
Female Growth Rate
N/A
Overall Age at Maturity (years)
3 in Oregon (Bourne and Smith 1972b, Wendell et al 1976, Hancock et al. 1979 all in Emmett et al. 1991)
Male Age at Maturity (years)
N/A
Female Age at Maturity (years)
N/A
Overall Length at Maturity (cm)
7 shell length (Bourne and Smith 1972b in Emmett et al. 1991)
Male Length at Maturity (cm)
N/A
Female Length at Maturity (cm)
N/A
Maturity/Temperature Relationship
N/A
Type of Reproduction
Gonochoristic, oviparous, iteroparous
Broadcast spawners (Bourne and Smith 1972b in Emmett et al. 1991)
Fecundity
Unknown (Emmett et al. 1991)
Spawning Habitat
N/A
Spawning Behavior
N/A
Time of Year of Spawning
January–March
February (peak off Oregon) (Machell 1968, Machell and DeMartini 1971, Breed-Willeke and Hancock, Robinson and Breese 1982, all in Emmett et al. 1991)
Number of Spawns per season
1+ (Bourne and Smith 1972b in Emmett et al. 1991)
Spawning/Temperature Relationship (°C)
Spawn as water warms (Bourne and Smith 1972b in Emmett et al. 1991)
Spawning/Salinity Relationship
N/A
Description of Eggs
N/A
Habitat where Eggs are found
Pelagic, coastal water (Emmett et al. 1991)
Days to Hatch
Trochophore larvae at 24 hours post-fertilization
Veliger at 48 hours post-fertilization (Emmett et al. 1991)
Time of Year when Eggs Hatch
N/A
Temperature for Egg Survival (°C)
N/A
Salinity for Egg Survival (ppt)
N/A
Predators on Eggs
N/A
Habitat where Larvae are found
Pelagic, coastal water (Emmett et al. 1991)
Days in Larval Stage
24 (at 15°C)
26 (at 10°C)
34 (at 5°C) (Bourne and Smith 1972a in Emmett et al. 1991)
Temperature for Larval Survival (°C)
20 (death) (Bourne and Smith 1972a in Emmett et al. 1991)
Salinity for Larval Survival (ppt)
N/A
Larval Food Preference
N/A
Habitat where Juveniles are found
Benthic infauna
Bays and estuaries (Emmett et al. 1991)
Length when Juvenile Settles out (cm)
0.027 (Bourne and Smith 1972a, 1972b in Emmett et al. 1991)
Temperature for Juvenile Survival (°C)
N/A
Salinity for Juvenile Survival (ppt)
N/A
Where and When Juvenile Feeds
N/A
Juvenile Food Preference
N/A
Habitat where Adults are found (depth in meters)
Benthic infauna, bays, and estuaries (Emmett et al. 1991)
Adults +2 cm cannot reburrow (Wendell et al 1976 in Emmett et al. 1991)
Temperature for Adult Survival (°C)
N/A
Salinity for Adult Survival (ppt)
N/A
Adult Feeding Method
Suspension/filter feeder (Haderlie and Abbot 1980 in Emmett et al. 1991)
Adult Food Preference
Diatoms, Flagellates, Dinoflagellates, Detritus (Stout 1967, Haderlie and Abbott 1980 both in Emmett et al. 1991)
Food Eaten in Laboratory Setting
Survives in aquariums with open systems or with algal culture in a closed system (Anderson 2001)
Amount of Food Eaten in Laboratory Setting
Optimum food suspension density is 95 mg/l 15–200 mg/l (range) (Bernard 1983b in Emmett et al. 1991)
Additional Laboratory Findings
In aquarium the individuals must have sand or gravel to bury (Anderson 2001)
Environmental Considerations
Beds have been closed in Washington due to pollution (Schink et al. 1983 in Emmett et al. 1991)
Commercial Fishery
Harvested from Northern California to British Columbia
225 tons annually (Emmett et al. 1991)
Fifth in volume for U.S. and Canada for Pacific coast clam harvest (Wolotira et al. 1989 in Emmett et al. 1991)
Market
Tough outer covering increases process/packaging time (Emmett et al. 1991)
Low meat yield (25–30% total body weight) (Quayle and Bourne 1972, Ricketts et al. 1985, Wolotira et al. 1989 all in Emmett et al. 1991)
Sold Fresh or Frozen
Rare to sell fresh since shell breaks easily (Emmett et al. 1991)
Style Species is Sold
Good for chowder
Clam steak
Canned (Emmett et al. 1991)
Additional Use of the Species
N/A
Shelf-life in Fresh State (days at 40°F)
Short (Emmett et al. 1991)
Shelf-life in Frozen State (months at 0°F)
N/A
Shelf-life Canned (months)
N/A
Weight sold in Oregon (kg)
N/A
Ornamental Market
N/A
Parasites or Disease
Paralytic Shellfish Poisoning
Coliform bacterial contaminant (Emmett et al. 1991)
Haplosporidan (43% infected in Yaquina Bay) (Armstrong and Armstrong 1974 in Emmett et al. 1991)
Pinnotherid crabs inhabit clam but do little harm (Haderlie and Abbott 1980 in Emmett et al. 1991)
Additional Remarks
N/A
Location where Species has been Researched/Farmed
N/A
Appropriate Aquaculture Systems
N/A
Recent Wild Harvest Data for Oregon
Data from the Oregon Department of Fish and Wildlife
(Pounds)
( U.S. Dollars)