TEMPORAL DISTRIBUTION AND REPRODUCTIVE PATTERNS OF HARPACTICOID COPEPODS FROM LOS ANGELES-LONG BEACH HARBORS

A study of reproductive patterns exhibited by harpacticoid copepods collected from submerged wood surfaces in Los Angeles and Long Beach Harbors indicates that two reproductive patterns exist, those species that breed continuously and those that breed seasonally. Species with continuous breeding generally had maximum reproductive peaks at different times of the year. Total harpacticoid densities recorded from this subtidal study are higher than those previously recorded from the sediment meiobenthos and are comparable to densities recorded for intertidal biotopes. The literature suggests that continuous breeding ofphytal harpacticoids is the result of an unlimited food supply and the opportunistic nature of the species and not temperature. The wood surface of harbor pilings, in addition to macroalgae, provides a substrate for microbiotic colonization which is grazed on by harpacticoids. Research on the ecology of harpacticoid copepods along the California coast has been limited. Barnard and Reish (1957) made some preliminary observations on the harpacticoids in Los Angeles-Long Beach Harbors while conducting a comprehensive study of marine borers. They noted more harpacticoids on wooden test panels in the winter than in other seasons and suggested that lower water temperatures, higher dissolved oxygen concentrations, and fewer fouling organisms were responsible for the greater number of harpacticoids during winter. Hicks (1979) reviewed breeding patterns of harpacticoids from interstitial, epibenthic, and phytal biotopes. He proposed that most benthic species tended to breed discontinuously, while the majority of phytal species bred throughout the year. Variability in reproductive patterns for individual species, however, has been found in some studies both within and between sampling locations (see Hicks and Coull, 1983, for review). The present study examines the temporal distribution and reproductive patterns of harpacticoids collected from wood surfaces in Los Angeles-Long Beach Harbors and makes comparisons with those patterns previously recorded. MATERIALS AND METHODS Harpacticoid copepods were collected from test panels that were suspended at 9 different locations at three depths in Los Angeles-Long Beach Harbors, from July 1976 through July 1977. The 9 stations were chosen as representative of the variety of physical and chemical conditions that exist in the harbors (Harbors Environmental Projects, 1976). The sampling apparatus consisted of test panels, suspended on a 6-mm nylon cord which was anchored at the bottom with a concrete weight. The cord, with 3 panels attached, and the weight were tied to cross piles underneath wharves. The 3 panels were situated along the cord to simulate the surface, middepth, and bottom areas of wood pilings. The panels were 20 cm by 6.2 cm Douglas fir. Each panel had a 9.5-mm hole bored through one end for attachment to the cord. Before being placed at station, all panels were soaked for 1 month in filtered (0.45-,um millipore) sea water to allow leaching of any residues. The sampling apparatus was left tied in place during the study year and the 3 panels were removed at specified intervals. For the most part, panels were immersed for monthly periods and then replaced with new panels. In addition, 3 collections were made of panels immersed for 1-, 2-, and 3-week periods, referred to as the recruitment study, and 5 collections of 2- to 6-month immersions, referred to as the long-term study. Panels were retrieved from the field by slowly raising the cord from the water and immediately depositing the panels in a plastic bag, where they were fixed with 10% formalin in sea water. Upon