Pleurobranchaea californica Distribution & Temporal Range based on trawl-data.
Pleurobranchaea californica inhabits the coastal Californian waters
(15C) at a medium-depth of between 40-1000 feet. These predatory slugs are usually
found crawling along the subtrate floor. Over the years, we have arranged trawls
either off the LA coast or just off Monterey bay throughout the year. Trawling
data collected over the last 10 years (for Monterey Bay) indicate that generally
Pleurobranchaea reside in deeper waters greater than 90 ft, given that
deep trawls provide the best catches. Historically, the best trawls have been
between 36deg 46'- 36 deg 50'N and 121 deg 48' 75'' - 121 deg 53' W.
Seasonally, these animals are more abundant in late summer, and throughout
the Fall (August-November); this is also the time period where we start pulling
up small, young animals. This data therefore indicates that P. californica
eggs hatch mid-summer, mature during the fall to fully mature adults that are
ready for reproduction during the winter months: December-March is the period
where we only pull in large adults between 70-200 ml in volume that are actively
mating.
Trawling data are extremely useful in determining the distribution density of various slug species on the sea floor - in the case of Pleurobranchaea, this may be the only data available - we actually use this information to model searching behavior.