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

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 Ammocoete

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 transmontanus Native 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 medirostris Native 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 petenense Introduced 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

AMERICAN SHAD vs. THREADFIN SHAD MYOMERE COUNT ON GUT APPROXIMATELY 30-35 American Shad MYOMERE COUNT ON GUT APPROXIMATELY 18-22 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 spots Long black spots on back and dorsal fin 13 - 19 rays

Coho Salmon (CHO) Oncorhynchus kisutch Native 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 Spots on upper caudal 12 - 17 rays

Black on gums and base of teeth Base of teeth white Edge of gums black Chinook Salmon Black on gums and base of teeth Small eye Coho Salmon Base of teeth white Edge of gums black

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

Juvenile Salmonids of the Central Valley 13 - 19 rays Chinook Salmon 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 12 - 17 rays Coho Salmon 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 8 - 12 rays Rainbow, Steelhead 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