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R/V Yellowfin cruise to Two Harbors, Santa Catalina Island, Los Angeles Co., CA, April 25, 2026

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biological dredge at about 22-28 m depth
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juvenile Octopus rubescens (red octopus)
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This egg mass is from Crossata californica (California frog snail), which lays its spirally set of egg cases in a half bivalve shell like this, , usually in a clam shell but occasionally in a shell from a different bivalve such as a scallop. In this case, the mother snail that would normally be brooding the egg cases is no longer attached. Each of many tiny embryos (visible inside egg cases) would normally hatch as similarly tiny veliger larvae, which are likely planktotrophic (feeding and growing while still in the planton), although this has not yet been confirmed to my knowledge, and neither has it for any other Eastern Pacific species of the caenogastropod family, Bursidae. In 1938, G. E. MacGinitie estimated (see Source) that a female C. californica had laid about 822,000 eggs, over four times as many eggs as his estimate for a neogastropod, Kelletia kelletii (Kellet's whelk) female's egg cases. (Source)
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another juvenile Octopus rubescens (red octopus)
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Another (see above) Crossata californica (Californiaifrog snail), this time with the mother attached, with the orange-spotted foot overlaying the egg cases.
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The shell of this Crepidula onyx (onyx slipper snail) has grown to conform to a rib in the shell of its host, Kelletia kelletii.
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Pelia tumida (dwarf teardrop crab), belongs to the true crab superfamily, Majoidea (spider and decorator crabs), family Epialtidae, subfamily Pisinae, and is distributed from southern California to northern Baja California, Mexico.
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A chiton, Lepidozona pectinulata (pectinate Lepidozona), from the underside of a rock, with some keeled calcareous tubes of serpulid polychaetes, Spirobranchus spinosus (California Christmas tree worm), in the upper right of the image.
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Anteaeolidiella oliviae(Olive's aeolid) is a small nudibranch that feeds on small anemones.
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This small chiton, a southern relative of a central California species that I named based on my PhD research, Cyanoplax caverna (sea cave brooder). Based on a molecular and reproductive study, I now consider these on Catalina Island to be part of a distinct Channel Islands endemic species that I am in the process of describing as a new species.
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A green alga, Codium setchellii, with a spongy nearly encrusting growth on intertidal rocks.
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The brown alga rockweed, Pelviopsis californica (formerly Hesperophycus californicus; common name olive or California rockweed) is fairly rare in the southern California intertidal but is quite common on Catalina Island. We found it occurring higher on rocks than Silvetia compressa ssp. deliquescens (golden rockweed), a subspecies found primarily on California's Channel Islands, including Catalina. It is smaller and more delicate than the familiar rockweeds of this species on California's mainland.
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The widespread green alga commonly referred to as Codium fragile (dead man's fingers) is apparently a complex of multiple similar appearing species, including both native and introduced species in California. They are interesting because they have giant elongate cells with numerous nuclei. Small and often cryptic sea slugs known as sacoglossans are often found feeding on these nuclei by piercing the cells and slurping up the nuclei.
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In addition to describing the new chiton species mentioned above, I am also involved with students and others in describing this chiton that we refer to as Nuttallina n.sp.A.
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Paralabrax clathratus (calico bass or kelp bass) are not true bass, but members of the sea bass family, Serranidae.
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