Study Population
Fieldwork was conducted on reefs near Mahonia Na Dari Research and Education Center in Kimbe Bay, Papua New Guinea (5.1666667°S 150.5°E) using SCUBA. These nearshore reefs support a population of over 100 groups of Amphiprion percula living within magnificent sea anemones Heteractis magnifica. From May 26 to June 23 in 2017, 117 groups were located and marked with numbered tags for identification. The experimental manipulation was conducted for two lunar months from June 24 to August 21, 2017. Lunar months were used rather than calendar months because pairs breed on lunar, semi-lunar, or trient-lunar schedules. Groups consisted of up to 5 resident fish (female, male, and 0 to 3 subordinates) with an average of 2.9 (+/- 0.1 SE) fish across all groups. Of the 117 groups, 52 (44%) were observed with eggs at least once in the lunar month before the manipulation began. These 52 breeding groups were distributed across 10 reefs, 5 of which were surveyed each day, such that all 52 groups were surveyed every other day throughout the study.

Body Size
To determine if there are positive correlations between habitat quality and parental body size, female standard length (FSL) and male standard length (MSL) were measured. The female and male from each group were captured using hand nets in the week before the start of the experiment (week of May 26, 2017) and in the week following the end of the experiment (week of August 21, 2017). Each fish was photographed to identify individuals by their color patterns and to confirm that they survived and did not move between anemones. The standard length (SL) of each fish was measured to the nearest 0.1 mm using calipers, and the average of the two measurements (start and end) provided a single measurement of FSL and MSL.

Reproductive Success
To determine if there are positive correlations between habitat quality, body size and reproductive success, reproduction was monitored for all 52 groups every other day. Reproduction was detectable by the behavior of the male and the presence of eggs at the base of the anemone. The exact age of the eggs was determined by their color (day 1 = orange, day 2 = orange-brown, day 3 = brown, day 4 = black eyes, day 5 = silver eyes, day 6 = silver eyes with pupils, day 7 = gold eyes with pupils). Eggs hatched after 7 days. Photos were taken of every clutch observed with an Olympus Tough TG-870 camera (Olympus, Tokyo, Japan) early (day 1 or 2) and late (day 6 or 7) in development.

Parental Care
To determine whether parental care was positively correlated with habitat quality, other parental traits, and reproductive success, 29 minute videos were taken of parental behavior early (day 3 or 4) and late (day 6 or 7) in development by setting up a tripod with an underwater camera (Olympus Tough TG-870) centered on the location of the eggs.

Feeding Manipulation
To determine whether the environment generates positive correlations between parental traits, feeding manipulations were conducted. One lunar month of baseline data was collected (May 26 – June 23, 2017), followed by two lunar months of feeding manipulation (June 24 – August 21, 2017). Of 52 breeding groups, 25 were given supplemental food and 27 served as controls. As reefs were located at different distances from shore, and some anemones were bleached, groups were randomly stratified to ensure equal amounts of fed/control groups for reefs closer to shore (N = 4 reefs, N = 32 anemones) versus further from shore (N = 6 reefs, N = 20 anemones) and for bleached (N = 10) versus unbleached (N = 42) anemones. Average female size was similar in fed (average SL = 52.8mm +/- 0.87SE) and control groups (average SL = 52.3 +/- 1.12SE).

Fed groups were supplemented with 3ml freeze dried brine shrimp (Omega One, OmegaSea LLC, Sitka, AK) and 3ml fish pellets (Marine Life Spectrum, New Life International, Inc., Homestead, FL). Food was kept dry in capped tubes until delivery. Brine shrimp (positively buoyant) were delivered first, by squirting the shrimp just below the anemone with a pipette. Pellets (negatively buoyant) were delivered second by opening the vial and tipping them down onto the anemone. Through this method, most food was either immediately consumed by the fish or stuck among anemone tentacles, where the fish could consume it. Some food was consumed by the anemone or other fish species nearby. Confirmation of successful administration of food was made by observing the male and female of each group consuming at least one pellet or shrimp. Control groups received a sham feeding treatment, using an empty vial and an empty pipette, to keep disturbance to all groups consistent.

feeding_expt_2017.csv