Within the Lower Sacramento and San Joaquin Rivers, Delta and shoreline Bay habitats

IDENTIFICATION OF FISHES

USFWS Juvenile Fishes

Monitoring Sites

General Anatomy

Mouth Structure

Dorsal and Anal fin ray counts

First rudimentary ray is not counted

Last ray is always treated as a double ray divided to the base of the fin

Lamprey Family, PETROMYZONTIDAE

Anadromous, some freshwater

Lampreys have a notochord and a cartilaginous skeleton

Do not have jaws or paired fins

Larvae, known as ammocoetes

Brook lamprey are nonpredaceous

Lamprey Lamprey AmmocoeteAmmocoete

Pacific Lamprey(PL)

Lampetra tridentata

Native Four pairs of

lateral tooth plates

Supraoral plate with 3 sharp cusps

Adult avg. TL = 400mm - 690mm

Anterior Teeth

Supraoral Plate

Lateral Tooth Plates

Transverse Lingual Lamina

River Lamprey(RL)

Lampetra ayresi

Native 3 pairs of lateral

tooth plates

Supraoral plate with 2 sharp cusps

Center cusp on transverse lingual lamina large

Adult avg. TL 170mm, never > 320mm

Anterior Teeth

Supraoral Plate Lateral

Tooth Plates

Transverse Lingual Lamina

Sturgeon Family, ACIPENSERIDAE

Heterocercal tail

Cartilaginous skeleton

Five rows of large bony plates instead of scales

Highly protrusible, bottom-oriented mouth preceded by four barbels

White Sturgeon(WST)

Acipenser transmontanusNative

Barbels are closer to tip of snout than mouth

No dorsal plates behind dorsal fin

1 row of 1 - 4 plates between pelvic and anal fins

38 - 48 lateral plates

Green Sturgeon(GST)

Acipenser medirostrisNative

Barbels closer to mouth than to tip of snout

1 - 2 dorsal plates behind dorsal fin

Two rows with 4 - 8 plates each between pelvic and

anal fins

23 - 30 lateral plates

Herring Family, CLUPEIDAE

Marine, anadromous and freshwater

Silvery deciduous scales and thin, deep bodies with a sharp keel on the belly.

Herrings have highly protractile jaws and long, fine gill rakers

Pacific Herring(PAH)

Clupea harengus

Native No black

spotting on sides

Origin of pelvic fins under midportion of dorsal fin

Teeth present on vomer (roof of mouth)

39 mm FL

American Shad(AMS)

Alosa sapidissima

Introduced Row of black

spots on sides

16 - 17 ventral scutes posterior to pelvic fin base

Length to 750mm TL

Threadfin Shad(TFS)

Dorosoma petenenseIntroduced

Thread-like projection at posterior edge of dorsal fin

8 - 12 ventral scutes posterior to pelvic fin base

One black spot posterior to operculum

Deeper bodied than American shad

Length to 220 mm TL

MYOMERE COUNT ON GUTAPPROXIMATELY 18-22

Threadfin Shad

MYOMERE COUNT ON GUTAPPROXIMATELY 30-35

American Shad

AMERICAN SHAD vs. THREADFIN SHAD

Photos: Rene Reyes

Anchovie Family, ENGRAULIDIDAE

Mostly marine

Overhanging snout

Long upper jaw extends behind the eye

Northern Anchovy(NAN)

Engraulis mordax

Native Snout

overhangs lower jaw

Origin of anal fin under or posterior to last few soft-rays of dorsal fin

Pectoral axillary scale more than half the length of pectoral fin

Salmon and Trout Family, SALMONIDAE

Native to cooler waters of the northern hemisphere

Possess an adipose fin and an axillary scale at the base of each pelvic fin

Eleven species native to California

Chinook Salmon(CHN)

Oncorhynchus tshawytscha

Native Numerous small

black spots on both lobes of the caudal fin in adults

6 - 12 parr marks are wider than spaces in between

Leading edge of anal fin is shorter than length of base

Adipose fin clear with dark upper edge in juveniles

Tail covered with spotsLong black spots on back and dorsal fin

13 - 19 rays

Coho Salmon(CHO)

Oncorhynchus kisutchNative

Anal fin is sickle-shaped, leading edge is longer than base

Adipose fin has dark pigment on anterior and dorsal margin only

8 - 12 parr marks are narrower than the spaces in between

Caudal, anal and adipose fins are pale orange

12 - 17 rays

Spots on upper caudal

Coho SalmonCoho Salmon

Chinook SalmonChinook Salmon

Base of teeth white Edge of gums black

Black on gums and base of teeth

Small eye

Rainbow Trout (Steelhead)(RBT)

Oncorhynchus gairdneri

Native Spots on dorsal

fin of fry 8 - 13 parr marks

are narrower than the spaces in between

Adipose fin has continuous rim of pigment in juveniles

First dorsal ray is black on fry

Uniform spots on tail

Square tail

Dorsal fin has black spots and black first ray, and a white tip

Adipose has continuous rim of black pigment

Anal fin has anteriormost ray about equal to the length of fin base

Anal fin is sickle-shaped, leading edge is longer than base

Leading edges of anal and dorsal fins have white followed by black

Adipose has black pigment on anterior and dorsal margins

Fins are pale orange

Anal fin has white leading edge and is not sickle-shaped, leading edge is shorter than base

Adipose has some black pigment on dorsal margin only

Dorsal fin has dark leading edge

Juvenile Salmonids of the Central Valley

13 - 19 rays

Chinook Salmon

12 - 17 rays

Coho Salmon

8 - 12 rays

Rainbow, Steelhead