Point Lobos Nudibranch Project Topics for Tonight • Project Design, Location and Transect Selection • Nudibranch Identification • Species in the Study • Look-alikes • Sampling Techniques and Data Sheets • Q & A Project Design • Project Design, Location and Transect Selection • Science goals are still being defined. • Hope is to maximize the value of any data we collect. • Cover a variety of species and habitats. • Ease of study was also important. • Sites need to be near each other to maximize data collection time. • Sites need to be easy to find. • Transects need to be easy identify for repeatability. • Species covered need to be common and diverse. Locations • We have chosen two areas for study. • The North end of the Middle Reef • The North end of the Hole-in-the-wall Reef • Each reef will be divided into 4 transect zones. • East Wall • North Wall • West Wall • Top (defined as anything with less than 45 degrees of slope. • Actual transect areas are TBD and will need to be surveyed. • Each transect area needs to be roughly the same size • Transects must be easily identifiable. Locations Rationale • Middle Reef and Hole-in-the-wall Reefs are easily locatable underwater. • Both sites have good populations of nudibranchs. • Both sites have diverse habitat areas. • Hole-in-the-wall Reef may be lacking in “top” and North areas. • A survey will help here. • We’re open to other suggestions. Species in the Study • We have 14 species in the study. • All are at least reasonably common in Whaler’s Cove. • They represent a wide variety of species and prey items. • They are for the most part relatively easy to identify. Hermissenda crassicornis • Relatively easy to ID • Note the yellow racing stripe on the head with the blue edging. • Cerata color can vary widely in different individuals. Go with the yellow racing stripe. • Weakly annulate rhinophores. • Typically eats hydroids. Phidiana hiltoni • Relatively easy to ID • Note the red stripe across the oral tentacles. • Also has a red band on the rhinophores. • Probably the most common aeolid in Whaler’s cove. • Eats the hydroid Hydractinia. Flabellina trilineata • Relatively easy to ID • Has 3 white stripes. One down the back and one on each side. • Middle stripe splits and goes down each oral tentacle making a Y shape at the head. • Eats various hydroids. Dendronotus albus • White with yellow to orange markings on the cerata and rhinophores. • Is never purple like the very similar Dendronotus diversicolor. • 4-7 pairs of gill tufts. • Dendronotus diversicolor usually only has 4 and never more than 5 gill tufts. • Dendronotus diversicolor is much more rare here. • Eats hydroids. Tritonia festiva • Translucent with white markings. • Has network of white stripes on its back. Similar (but larger) Tritonia diomedea lacks these markings. • Gill tufts down each side. Also note the frontal veil • Eats gorgonians, sea pens and other octocorals. Berthella californica • Not actually a nudibranch. Is actually a pleurobranch. • Translucent with white spots. Usually has white edging around the mantle • Rolled rhinophores come out from under the top of the mantle. • Gills are on the right side. • Has a triangular frontal veil. • Unknown prey, possibly tunicates or sponges. Limacia cockerelli • Usually quite small (less than 15mm). • Has many club-shaped tubercles. • Rhinophores and gills usually darker than the tubercles. • Gills sometimes white. • Eats bryozoans. You can see the prey bryozoan in the right side of this picture. Triopha catalinae • Usually larger than Limacia cockerelli. • Tubercles are bumps but not club shaped. • Rhinophores and gills usually the same color as the tubercles. • Has a prominent frontal veil with 8-12 tufted processes. • Eats bryozoans. Doris odhneri • Very large (usually > 150mm). • Pure white or possibly very pale yellow. • No spots or other markings. • Smooth, large rounded tubercles. • Eats sponges. Peltodoris nobilis • Typically large (often > 100mm). • Yellow with black spots. Spots never appear on the tubercles, always between them. • Occasionally orange base color if living on an orange sponge. • White gills. • Smooth, large rounded tubercles. • Eats sponges. Dialula sandiegensis • Medium sized - typically 50-80mm. • Easy to identify. • White or cream colored with large, dark spots. • Spots usually but not always a donut shape. • Spots often but not always in pairs on either side of the back. • White gills. • Eats sponges. Doriopsilla albopunctata • Medium sized - typically 50-80mm. • Easy to identify. • Pale yellow with white spots. • White gills. • Eats sponges. Rostanga pulchra • Small - typically 10-20 mm. • Orange, occasionally with black spots. • Orange gills, arranged in a ring. • Unique fluted rhinophores (see detail in next slide). • Eats orange sponges and nearly always found on the food sponge. Rostanga pulchra • Detail of rhinophores. Cadlina luteomarginata • Medium sized - typically 50-80mm. • Very common. • Translucent with yellow spots. • Yellow edging around the mantle. • Spots often small. • White gills tipped with yellow. • Short rhinophores compared to Acanthodoris hudsoni. • Smooth tubercles compared to Acanthodoris hudsoni. • Eats sponges. Common Look-alikes • Following are some of the more common Look-alikes. • Several of these are rare relative to the ones in the study. • Other more common ones should be readily differentiated from similar species that are part of the study. Doris montereyensis • Medium sized - typically 50-80mm. • Not in the study - similar to other yellow dorids. • Yellow with black spots and yellow gills. • Spots extend onto the tubercles (compare with Peltodoris nobilis). • Eats sponges. Geitodoris heathi • Medium sized - typically 50-80mm. • Not in the study - similar to other yellow dorids. • Yellow or occasionally white with black spots and whitish gills. • Spots often small like black pepper flakes. • Can have a blotchy appearance. • Frequently has small specks on the gills (extreme example here). • Eats sponges. Geitodoris heathi • Color variation. • If you can’t ID a yellow or white dorid call it Geitodoris heathi and move on. Aldisa sanguinea • Small - typically < 50 mm. • Not in the study - similar to Rostanga pulchra. • Rare • Usually two large spots between the rhinophores and the gill opening. • Conventional lamellate rhinophores. • Often has tan saddle markings. • Eats sponges. Acanthodoris hudsoni • Small - typically < 50 mm. • Not in the study - similar to Cadlina luteomarginata. • Rare • Rhinophores long compared to Cadlina luteomarginata. • Tubercles cone shaped and spikey. • 5 distinct gill tufts instead of 6 softer ones as in Cadlina luteomarginata. • Eats sponges. Prey Item Examples • Following are some pictures of typical examples of prey items for nudibranchs. • Sponges • Bryozoans • Tunicates • Hydroids Sponge Sponges Bryozoans Bryozoans Bryozoans Tunicate Tunicate Tunicates Hydroids Hydroids Hydroids Hydroids Sampling Techniques and Data Sheets • Go Slow! • Study areas are designed to assume 30 minutes per reef area. • Don’t be afraid to get close and use your hands. • Especially in areas with hydroids or algae cover. • We’d like to sample four times per year. • One thought is to use a variant of presence/absence sampling. • Zero • One to three • Three to ten • More than ten. Sampling Techniques and Data Sheets Name: Date: Site: Temp: E N W T C. luteomarginata D. sandiegensis D. odhneri ... Sampling Techniques and Data Sheets Name: Date: Site: Temp: E N W T C. luteomarginata D. sandiegensis D. odhneri ... Q & A.