(DRAFT) - Taxonomy
Species perch, pile
Species Id M010190
Date 26 AUG 96
TAXONOMY
NAME - perch, pile
OTHER COMMON NAMES - pile surfperch, fork-tail perch and porgy
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata,
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Perciformes,
FAMILY AND SUBFAMILY - Embiotocidae,
GENUS AND SUBGENUS - Rhacochilus,
SPECIES AND SSP - vacca,
SCIENTIFIC NAME - Rhacochilus vacca
AUTHORITY - Girard
TAXONOMY REFERENCES - 225
Taxonomy - 1 (DRAFT) - Status
Species perch, pile
Species Id M010190
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
REFERENCES FOR STATUS - 225
COMMENTS ON STATUS -
The pile perch is among the eight to ten species of the family that are
important in the commercial "perch" fishery. The annual commercial catch of
surfperches has varied substantially over time. The market for fresh
"perch" fillets is relatively small.*225*
Pile perch are taken by sport fishermen, mostly from piers, jetties, skiffs,
or the shore. From 1958 to 1961, sport fishermen caught an estimated 5000
rubberlip seaperch per year in the area between Point Arguello and the
Oregon border. The annual catch south of Point Arguello was believed to be
double this number.*225*
Status - 1 (DRAFT) - Distribution
Species perch, pile
Species Id M010190
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine RB.
Marine RF.
Marine RS.
Marine AB4
Marine RB.
Marine RF.
Marine RS.
Marine AB4
REFERENCES FOR NWI - 225
COMMENTS ON HABITAT ASSOCIATIONS -
Rocky shores and near kelp, pilings, and underwater structures; inshore and
to 46 m.*225*
Pile perch prefer areas of high-relief substrate and dense algal growth
that harbor abundant invertebrate prey. Harsh storms may scour reef
habitat and remove kelp.*225*
Habitat Associations - 1 (DRAFT) - Food Habits
Species perch, pile
Species Id M010190
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 225
LIFESTAGE FOOD FOOD PART
Adult Crustaceans Not Specified
Adult Bivalve Molluscs See Comments
Adult Cirripeds Not Applicable
Adult Snails Not Specified
Adult Malacostraca Not Specified
REFERENCES FOR ADULT FOOD - 225
COMMENTS ON FOOD -
Surfperches are mainly benthic grazing carnivores that have relatively small
mouths and feed on invertebrates--chiefly crustaceans.*225*
Pile perch have well developed, fused pharyngeal tooth plates that enable
the fish to crush hard-shelled invertebrates. This specialization has led
some authors to place pile perch in a separate genus Danalichthys. Pile
perch feed on whole mussels (about 2.5 cm long) in the laboratory, and field
studies have shown that a wide variety of hard-bodied prey are taken.
Twenty-seven prey taxa in the diet of pile perch at Redondo Beach,
California, have been listed. Studies have indicated that pile perch were
consistent predators on intertidal snails in British Columbia; they also ate
barnacles, small crabs, and mussels.*225*
COMMENTS ON ADULT FOOD -
Surfperches are mainly benthic grazing carnivores that have relatively small
mouths and feed on invertebrates--chiefly crustaceans.*225*
Pile perch have well developed, fused pharyngeal tooth plates that enable
the fish to crush hard-shelled invertebrates. This specialization has led
some authors to place pile perch in a separate genus Danalichthys. Pile
perch feed on whole mussels (about 2.5 cm long) in the laboratory, and field
studies have shown that a wide variety of hard-bodied prey are taken.
Twenty-seven prey taxa in the diet of pile perch at Redondo Beach,
California, have been listed. Studies have indicated that pile perch were
consistent predators on intertidal snails in British Columbia; they also ate
barnacles, small crabs, and mussels.*225*
Food Habits - 1 (DRAFT) - Environment Associations
Species perch, pile
Species Id M010190
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
A Water Temperature: Specified in Comments
J Bottom Type [Aquatic]: Rooted aquatic vegetation
A Density of Aquatic Vegetation: Low
J Density of Aquatic Vegetation: High
A Water Depth Preference: 5-10 ft.
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 225
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 225
REFERENCES FOR JUVENILE ENVIRONMENTAL ASSOC_ - 225
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Adults are found in water cooler than 16 degrees C and tend to avoid warmer
water.*225*
Adults are typically in areas with little cover.*225*
They prefer colder water so that during the summer and fall they are in
deeper water, around 8 m. In the winter and spring they re at about 4-5 m.*225*
Young of pile perch are found in the kelp understory or areas with abundant
cover.*225*
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Adults are found in water cooler than 16 degrees C and tend to avoid warmer
water.*225*
Adults are typically in areas with little cover.*225*
They prefer colder water so that during the summer and fall they are in
deeper water, around 8 m. In the winter and spring they re at about 4-5 m.*225*
COMMENTS ON JUVENILE ENVIRONMENTAL ASSOC_ -
Young of pile perch are found in the kelp understory or areas with abundant
cover.*225*
Environment Associations - 1 (DRAFT) - Life History
Species perch, pile
Species Id M010190
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY:
Surfperches are characterized by having cycloid scales covering the body and
forming a sheath at the base of the dorsal fin. The dorsal fin is single;
the spinous portion gradually increases in height to the point where it
joins the soft rayed portion. There are three anal-fin spines. No teeth on
vomer or palatines. Branchiostegals 5-6; gill membranes free from the
isthmus. All surfperches are viviparous; the male has a distinctive anal
gland on the anal fin.*225*
Rhacochilus vacca: Rays at front of soft dorsal fin long--about twice as
long as dorsal fin spines. Caudal fin deeply forked. Dorsal fin spines
9-11; soft rays 21-25. Anal fin rays 25-31; pectoral fin rays 19-22;
vertebrae 34-39. Scales along the lateral line 56-69 + 5-8 on tail. Gill
rakers 18-22 on the first arch. Ground color silvery overlain with brown or
sooty tones; most heavily pigmented on dorsal surface. Fins dusky. Maximum
length 44 cm total length (TL).*225*
REPRODUCTION:
Embryos are nurtured in the female before birth and may be fairly large as
newborn young.*225*
The testis index for male pile perch from Yaquina Bay, Oregon, peaked in
September and October; the highest index in late September was ten times
that in midsummer.*225*
Fecundity (brood size) is positively correlated with size, weight and age in female
pile perch. Fecundity of pile perch at the age of first reproduction (IV)
averages 11.7 and somestimes exceeds 60 in older fish (ages VII-X).*225*
Breeding behavior has been observed in pile perch. A pair of pile perch
swimming in the same direction suddenly turn on their sides or upside down
and bring their urogenital openings into contact for an instant.*225*
Since surfperches are viviparous, the eggs and embryos develop within the
maternal ovaries. The embryos obtain nourishment for growth by absorbing
the rich ovarian fluid. The dorsal and anal fins of the embryo are large
and vascular and have spatulate extensions that lie in close contact with
the well-vascularized ovarian wall. Respiration also takes place between
these spatulate fins and the ovarian wall. The oxygen capacity of the
ovarian fluid of pile perch is about the same as that of 10 ppt seawater.
This fluid apparently lacks respiratory pigments.*225*
During gestation the fins change little in surface area, while the body area
does change. The spatulate fin extensions are absorbed before birth.*225*
In British Columbia young pile perch are born in mid to late August.*225*
BEHAVIOR:
Studies in and near the kelp forests off Santa Barbara, California, have
indicated that pile perch generally remain in the mid-water and suprabenthic
zones both day and night. They are often seen scattered in the water column
at night. The relative abundance of this species varies seasonally and
diurnally. Although the seasonal data is not conclusive, it appears that
this species is most abundant in December to February. Pile perch are most
abundant during the day.*225*
Researchers who made monthly fish collections at Big Beef Harbor in Hood
Canal, Washington, reported that pile perch ranked third in abundance there.
However, they disappeared by November and did not reappear until the
following July. The hypothesis was that pile perch enter shallow water in
summer and move to deep water in winter. It was also noted that adult pile
Life History - 1 (DRAFT) - Life History
Species perch, pile
Species Id M010190
Date 26 AUG 96
perch were most abundant during winter and spring months at a Redondo
Beach, California, breakwater. Juveniles first appeared in May and
abundance peaked in June. Adults commonly traveled in schools of 50 to 100
during winter months; they lived in shallow water during winter and spring,
seemingly because of a preference for water temperatures of 16 degrees C or
lower.*225*
LIMITING FACTORS:
Adult pile perch are generally too large for most predators but the young
are vulnerable to predation by many piscivores. Kelp bass (Paralabrax
clathratus) is listed as a predator of young surfperch near Santa Barbara,
California. Also listed are electric rays, sharks, large serranid basses
and pinnipeds as potential surfperch predators. The birth of young
surfperches in late spring and early summer coincides with maximum refuge
protection in the kelp.*225*
Researchers summarized the parasites recorded form pile perch from
Washington to Baja California. It has been suggested that ecological rather than phylogenetic factors may be responsible for particular parasites being found in a given host spcies.
Studies have described the copepod Clavella embiotocae, found on gill
filaments of pile perch collected near the sewage outfall off Orange
County, California. Studies have also described Colobomatus embiotocae as
a new copepod species infecting pile perch in southern California.*225*
POPULATION ATTRIBUTES:
Pile perch have a life span of 7 to 10 years.*225*
Studies that used the scale method of analysis to back-calculate length at
age for pile perch, reported that males and females grew at about the same
rate for the first 3 to 4 years. Thereafter, the growth rate of males
declined more rapidly than that of females. Researchers calculated a daily
growth rate for pile perch embryos of nearly 5% (wet weight).*225*
LIFE HISTORY CODES -
Foraging Strategy: Grazing
Foraging Sites: Flowing water - aquatic weedbeds/vege
Display Site: Water
Nest Materials: No nest structure
Periodicity: Active in day
REFERENCES FOR LIFE HISTORY- 225
Life History - 2 (DRAFT) - Management Practices
Species perch, pile
Species Id M010190
Date 26 AUG 96
MANAGEMENT PRACTICES
Management Practices - 1 (DRAFT) - References
Species perch, pile
Species Id M010190
Date 26 AUG 96
References
225 * Fritzsche, R.A., T.J. Hassler. 1989. Species Profiles:
Life Histories and Environmental Requirements of Coastal Fishes
and Invertebrates (Pacific Southwest) - Pile Perch, Striped
Seaperch, Rubberlip Seaperch. 82(11.103) (ed.). National
Wetlands Research Center Slidell, LA:15.
References - 1