langzi's Journal

By Elyse Hartmann, Madeleine Yang, and Marina Thompson
Survey dates: 5/19/24 - 5/21/24
Location: Paea, Tahiti, French Polynesia

Introduction
In this study we started a beach profile to monitor how the beach elevation changes over time. The objective given was to measure the degree of which the terrain slopes by looking at transects going through the Paeanfish pond and outside of it, by our client Thomas. Our monitoring reveals information on the relationship between current and sand deposition, as well as documenting erosion.

Methods
We started by measuring the dimensions of the fish pond. Each wall of the fish pond and the opening on the beach were measured to the outermost part.
In order to get a representative profile of the beach’s elevation, we split the area into four, parallel, 32 meter transects with 5 measurements taken within. Two transects went through the fish pond and two were on either side of the fish pond walls.

To gather the measurements, we used the south most noni tree in front of the pond as a fixed point to standardize the starting point for measurements. In the future if this tree is no longer there, start measurements 0.34m to the left of the southern mist metal pole in front of Thomas’ property. To calculate the slope of the beach, tape lines 120cm high on two sticks were used in conjunction with a protractor: we recorded the angle from the higher stick to the lower stick by looking at the other tape mark through a straw on a protractor. The protractor had a string with a weight attached to it, so one team member could read the angle indicated by the string, while one was looking through the straw. This was repeated to get the angle and hypotenuse 20 times around the fish pond in a systematic manner. Then the height from the original (horizontal point near noni tree) was calculated using cosine.

In order to measure the speed of the current we strategically choose five spots around and within the fish pond, making sure to intercept all the previous four transect lines. We took measurements on each side of the fish pond’s interior (north and south), two outside the fish pond’s walls (north and south), and one west of the fish pond outside the walls. At the spot, one team member held each side of the tape measure and the third team member recorded the time of when the buoy went past the designated marks. The buoy was dropped at 0m and floated downstream to pick up speed, once it reached 3m a stopwatch was started. When the buoy reached 7m (a distance of 4m recorded) the stopwatch was stopped and the time was recorded. The data was then averaged to find the speed in meters per second (m/s).
Safety precautions such as wearing shoes were taken when walking in the lagoon to avoid complications with venomous benthic animals.

Results
NOTE: Our depth measurements are not correct. We have determined that our measurements are proportional to each other and the beach slopes and current speeds are correct. (Therefore, figures 2-3 and 5 are all correct). However, the depth measurements do not reflect the real depths from point zero, so figure 1 is visually correct, but numerically incorrect. This is due to an unknown error in methods or calculation. We suggest future groups look further into this.

The measurements of the fish pond walls were 14.5m in the South wall, 17.1m for the East opening, 15.7m for the North wall, and 16.8m for the West wall.

Figure 1 shows cross sections of the beach along four different lines. It shows that the southmost line (site 1) has the lowest depth at the start and highest depth before the waterline. Whereas, the part of this beach cross section that is below the waterline has the second largest depth from point zero. If you look at site 2, the opposite is happening, the depth is the 3rd largest before the waterline and the shallowest after the waterline. Site 3 on the northern side inside the fishpond has the greatest depth throughout the whole transect line with the deepest part at 5.32 meters below the wall of the property.

These results correspond with calculations of the slopes showing that site 3 has the greatest negative slope overall of -0.22 and Site 2 has the lowest negative slope of -0.13. All of the slopes within each transect line had standard deviations between 0.08 and 0.15 showing a large amount of variation in slope within each site line. Though, transect 3 had the most slope variation.

In addition, the ocean currents at each location along the transect line sites differed. The current speed was highest deeper into the water west of westward fish pond wall where the current speed was 0.36 m/s. This is to be expected since the measurement was taken much deeper into the water. Location 1 was the next greatest along transect one (south most outside the fish pond) with a speed of 0.17 m/s. The lowest current speed was measured at site 2, where the average slope was the lowest as seen in figure 2. T-tests showed that there was a significant difference between the current speed between sites 1 and 2 with a P-value of 0.072.

Figures: https://docs.google.com/document/d/1s2taUzmCdVAy7Pd_E-1flnjZBLYdMdLJDsTSKIdLg3o/edit

Figure two represents the average slopes of our four transect lines. Site 3 had the greatest slope and figure two had the smallest. These were both the transects within the fish pond.

Figure 3 depicts the different current speeds at 5 locations, three outside of the fish pond and two within. Locations 1, 2, 3, and 4 each intercept the corresponding depth transect perpendicularly. Site 5 is parallel to the west wall, and had the highest current speed.

Figure 4 is useful in visualizing the different depths from the starting spot at different points in and around the fish pond. The depths ranged from .3 to 5.32 meters. The scale of colors goes from white/yellow (shallow change), to red/purple (deep change).

In order to establish long term visuals of how the fish pond changes shape and the walls shift, we took a photo standing from a perch on the bathroom wall. Future photos can be compared to this baseline- 5/21/24.

Discussion
Our results present a couple different patterns and findings that could be relevant to continue monitoring overtime.
The south side of the fish pond interior has a shallower depth and slope than the north side interior. Correlating this finding with lagoon current strength and direction can tell us about the possible future of deposition of sediment and changes of depth within the fish pond. The measurement can be used as a baseline measurement and repeated in the future to compare and quantify changes occurring within the fish pond.
Specifically, we found that the current is traveling northward, and we recorded a 0.6 meters per second slow down after the water crossed the south wall of the fish pond. Therefore, the higher elevation on site 2 can be correlated to sediment deposition due to slowed current speed after the fish pond wall.
Additionally, we want to note the relationship between the largest depths (at site 3), and the hole in the fish pond’s west wall, which overlaps with site 3. We observed that when a buoy was placed in a few meter’s radius of the opening, it would float towards that exit, slowly increasing in velocity, exemplifying this as an outflow spot for currents. This could help explain why the north interior side of the fish pond is deeper than the south, because of sediments being carried with currents leaving the pond at this exit (and other cracks and crevices along the north wall).
Numerically we recorded an average 0.3 meters per second increase in current speed on site three compared to site 2. But it’s relevant to note that we did not calculate current velocity specifically at the mouth of the west wall opening - which is where it would have been even faster, as observed visually by buoy movement. This solidifies the relationship between current direction, velocity, and deposition of sediment in and around the fish pond, especially when considering different physical features.
In the future we suggest groups do more measurements around the hole in the west wall. These could be current, depth, or sediment related to learn more about the erosion and deposition occurring in the fish pond and around the opening.

Errors
As this is the first beach profile there were a couple of human errors that can be addressed. One error would be that when measuring the dimensions of the fish pond we were at the water level. This may cause error as we may have not been aligned with the fish pond walls.
During the days that data was collected there were varying wind speeds between 3 and 5 on the Beaufort scale. We recorded the wind speeds at the time of each current trial in order to include a more accurate depiction of what was happening and why.
The wind made it difficult to fully straighten long transects and made it difficult to use the string method on our protractor when calculating angles of the topography’s slope. To reduce error, one person would look through the protractor while another person ensured the weight at the end of the string was indeed oriented downwards.
The large swell two weeks ago and other temporal weather could have affected the depth of the sediment and the current speeds.
In addition, there was an unknown error during data collection and processing, influencing the accuracy of our data.

SURVEY DATES: 05/19/2024 - 05/21/2024
SURVEY LOCATION: Paea Lagoon Aua i’a Fish Pond
AUTHORS: Jessie Segnitz, Uma Pant, Nicole Pianalto, and S. Tara Grover

INTRODUCTION:
In this survey, we observed the substrate inside, on top, and outside the Paea Lagoon Aua i’a Fish Pond. The fish pond is a Polynesian traditional practice of small scale fish collection that fell into disuse over time due to the effects of European colonization, commercial fishing, and globalization. We are building upon the previous studies done by Wildlands students in 2022 and 2023 in order to meet the needs of our client, a private individual interested in species and land conservation who owns a marine observatory on Tahiti.

The objective of our study is to determine the sea floor substrate and algae covers on the inside and outside of the fishpond, and top of the rock wall top itself. Further objectives of the research team were to establish measurement definitions for the average particle sizes of both "fine" and "coarse" sand to set a standard for future use, and second, evaluate the presence of patterns on the seafloor of fine and coarse sand areas. There is a current along the shore running south to north through the fishpond and our client is specifically interested in the influence of this current and how the rock wall may act as a sieve or filter, changing the concentration of the sand types on the different sides of the wall. Earlier studies concluded that there was no statistically significant difference in substrate coverages outside and inside the fishpond, however, they did not account for the difference between fine and coarse sand, which is the knowledge gap we addressed with our survey.

We hypothesized that there would be a significant difference in the coverage of the different sand types on the south and north side of the wall. We further hypothesized that there would be a difference in overall substrate coverage inside and outside of the fish pond walls because of the barrier effects of the wall on the current's ability to move and transport substrate types through the area.

METHODS:

FIRST SURVEY — INSIDE FISH POND
We used a 50 x 50 cm quadrant to survey percent coverage of different substrate and algae types. We used a random number generator to generate 10 coordinates within the size of the fish pond which is roughly 15 x 15 meters. Using the bottom right corner of the fish pond (Northern corner) as our (0,0) origin point, we used a transect to measure out the predetermined coordinate points to the South along the shore (x-axis) and out into the water (y-axis) and placed the bottom right corner of the quadrat at each point. Our randomly-generated coordinates were (8, 12), (5, 1), (2, 7), (10, 9), (14, 3), (9, 11), (6, 12), (7, 9), (12, 9), (13, 2).

For this survey as well as Survey #2, we evaluated percent coverage of the following categories: fine sand (with the majority under 1mm length of grain on average), coarse sand (over 1mm length of grain on average), bare rubble (chunks of substrate between 2.5-10 cm, including stone, dead coral, shells), bare rock (over 10 cm with no algae cover), and five types of algae. These types were turf algae (under 1 cm), and the macroalgae genuses: Halimeda, Padina, Turbinaria, and Dictyota. Two researchers both independently estimated the coverage of each type and then double verified with each other.

We made sure to step lightly to avoid disturbing substrates or moving any particles into or out of the quadrats. We also exercised a high level of caution to avoid contact with dangerous benthic species including the stonefish, by wearing neoprene boots and swimming when possible without touching the floor.

SECOND SURVEY —OUTSIDE FISH POND
Starting from the north fish pond edge at the point closest to the shore, we measured out 5 meters parallel to the shore. That would be our starting point of our survey line of 15 meters to the end of the fish pond walls. We did systematic sampling, so every 5 meters starting from 0 meters on the transect we would sample using a 50 x50 cm quadrat, putting the quadrat on the left side of the transect with the bottom right corner at the starting point. We did this for the north, west and south walls of the fish pond. We evaluated percent coverage of the same categories and methods as for Survey #1 (above).

THIRD, FOURTH, AND FIFTH SURVEY — SEDIMENT TRANSECT
In this survey we used line intercept sampling by using a transect adjacent to the interior and exterior wall, which we identified as the area on the seafloor closest to the rock wall that did not include any large rocks that made up the foundation of the wall. We evaluated percent sediment coverage of the following categories: fine sand (under 1mm length of grain on average), coarse sand (over 1mm length of grain on average), rubble (2.5-10 cm), rock (greater than 10 cm), and alive coral, all regardless of any algae cover on top. By looking at what sediment lay directly underneath the transect line we classified what sediment was present and the length of the section it created, for the entire 14.5 meters. We conducted this survey for the north, west and south side walls of the fishpond on both the inside and outer side of walls.

SIXTH SURVEY—- ON TOP OF WALL
For this survey we used systematic sampling using the 50 x50 cm quadrat and a transect laid out from the start of the rock wall for all three walls. We placed the bottom of the quadrant at 0m, 5, and 10 meters for each wall. The quadrat was placed in the very center of the wall, and at all survey points, the wall was thicker in width than 50 cm so the quadrat consisted completely of substrate from the wall itself. We looked down from an aerial view and measured the same substrate and algae types as previously mentioned in the other surveys. We repeated this method for all three walls for a total of 9 survey points.

SEVEN SURVEY — SAND MEASUREMENT
For this survey a team of two took samples of fine and coarse sand from inside the fishpond, scooping only the surface layer of sediment. We collected approximately 20 mm of sand and water for each. The samples were chosen based on visual differentiation, where the fine sand was scooped
from the left wall delta closest to shore inside the fishpond, and coarse sand from the center of the fish pond. The sand was laid out on a paper towel and a randomization method was used to choose 50 grains of sand to measure from each sample. Calipers were used to measure out the various particles in millimeters.

IMPROVEMENTS/ CHANGES FROM PREVIOUS SURVEYS

We used a 50 x 50 centimeter quadrat instead of the previous group's 1x1 m. This allowed us to take more accurate and detailed data on the coverage within our survey areas while still being a large enough surveyed area to be generalizable to the entire pond.

We know that the algae species and concentration can change due to seasonal and climate patterns. We did our own preliminary analysis of what types of macroalgae genuses were present when we got in the water, and created our own list of them to measure instead of using the previous groups. This was the same as the previous groups except for one exclusion, Sargassum, which was not present at this time, and one new inclusion, Dyctyota, which was present.

We did a randomized point intersect method for the inside of the fishpond instead of the previous groups' strategic sampling method because the fishpond is a big enough sample universe to benefit from a random sample to eliminate bias or accidental disproportionate inclusion or exclusion of substrate patterns.

We continued the original method of strategic sampling for the outside fish pond sampling universe, and for the walltop itself, because we felt that the narrow range of these areas would be better represented by consistent sampling. A visual analysis of the general substrate cover of the entire survey area confirmed that we were not overlooking any patterns due to this sampling method.
Surveying the wall top itself was also a new addition to this survey project that was not present in previous years. This allows us to set a baseline time zero (t=0) standard for wall composition which gives insight into the structural integrity of the stones based on how close together they are, and what substrate types are present among the cracks..
Another new addition was the specific line-intercept survey along the outer and inner walls that focused on determining patterns of sand dispersal through the walls.

RESULTS:

Please copy and paste the link below into your browser to view data sheets with graphical analysis

https://docs.google.com/document/d/1296DmEP9zlzIvRDUheGtx5jx7ANnlSfT8JGAyNMvuSI/edit

DISCUSSION:

Survey one data illustrates that the substrate cover inside the fish pond is mostly coarse sand and a scattering of rubble across the area. While the dominant algae inside the fish pond was Halimeda. In the survey two data, it portrays that the sediment composition outside the fishpond was mostly made up of fine sand and some coarse sand, while the algae was mostly turf. The differential sediment composition inside and outside the pond demonstrates that the fish pond creates a different sediment environment, which is reflected by the dominant algae that is growing in the area.

The survey three, four, and five data show sand patterns that are representative of the current flowing through the pond. The currents are coming from the south going north, parallel to the shore. Outside the southern wall there was a larger section of fine sand, while the interior of the fishpond there were three distinct sections of fine sand. This illustrated that the southern wall is filtering the fine sand into the pond at a relatively slow rate, with most of it concentrated on three sections that correlate with thinner and lower wall sections. While on the other hand, the opposite was reflected by the north wall, by the sand filtering out of the pond. The exterior of the wall substrate consisted of more fine sand than the interior of the wall reflecting that there is a large rate the fine sand is leaving the fish pond. With the influx of fine sand coming in at a slower rate and the outflux leaving at a greater rate, the inventory of the fine sand in the fish pond would be lower. This is also reflected in the data from survey one, the sediment coverage inside the fish pond, portraying that there was very little fine sand within the sampling sites that is a portrayal of the entire pond. Then with the west wall the sediment makeup of the interior and exterior was fairly similar with the percent of fine sand being around 30 percent. This similarity illustrates their is not that much if any sand movement between this wall.

For Survey 6 looking at substrate composition on top of the wall itself, we found that the turf (algae less than 1mm long on top of rock/rubble) dominated the bulk of the substrate available in this location, at 83%, as expected. The wall is composed of large rocks, and can resist wave action more so than coarse or fine sand, which can be washed away. Since the stones here are the original foundation of the fishpond from whare our client rebuilt it many years ago, it makes sense that turf covers almost all of the present stone content. The coverage of bare rock with no turf is only the parts of stones that are still above water even at high tide, so there was no ability for turf to settle and grow there. The areas that were not turf or stone are what is visible between the rocks when looking from an aerial view, ad thus they represent the cracks between the rocks which allow a view of algae content below and occasionally all the way down to the sand on the floor.

During Survey 7, we revealed key information about classifying the difference between the size of coarse and fine sand. We found that the coarse sand had a median of more than 1mm in particle size, and the fine sand had a median size of less than 1mm in particle size. We used this understanding to clarify our data for both types of sand during the other survey collections, where we used visual markers to identify each type. This classification can also be used for future studies as a standardization of the monitoring project.

It's important to note there was an ocean swell a couple weeks ago that washed away different substrate from the location that may have previously been present in the area. For example, certain algae species and fine sand may have been washed away, influencing the current composition of the inside and outside of fishpond wall barriers. This may contribute to significant differences between this survey and the previous ones, although other factors such as seasonal differences and simply the regular wave and wind action of many months will also produce these differences.

Overall, there are noticeable trends in the differences with sand cover on the inside versus the outside of the fishpond.
The higher concentration of fine sand outside could be due to current and wave action pushing coarser, heavier sand particles inside the fishpond that has nowhere to go, whereas Fine sand can be lifted away by wave action. The fact that turf on rock substrate covered most of the fish wall shows how the stones have been present long enough to accumulate turf cover.
Another explanation for the lack of other types of substrate and algae coverage may be due to the nature of intertidal zone harsh conditions, which only support life for the most hardy species that can survive high and low temperatures, water and salinity levels, and have increased mechanical wave action that make it difficult to establish a presence on the rocks and moves sediment rather quickly, not allowing for settlement.

We also noted an interesting observation from this year's data versus last year's projects. Halimeda is the most common algae found in and around the pond, which is different from the rest of the coral reef areas that the research team has seen across Tahiti and Moorea.

PROPOSALS FOR FUTURE METHODS:

We propose that future projects continue to differentiate between fine and coarse sand, so that a standard can be maintained for data collection over time in consideration of factors such as current speed and wave action.
A proposal for future groups is to analyze the structure of the wall to determine what qualities exactly lead specific sections to allow more fine sand through the stones.
The line-intercept survey of sand cover along the sides of the walls should be repeated to track change over time.
We also recommend separating the data collection between algae biodiversity (different genuses) and mineral substrates (coral, sand types, rock, rubble) as separate surveys, where the mineral substrate survey does not regard algae coverage.
The algae biodiversity survey should also include a difference between turf on rock vs. turf on rubble, to make sure that it is clear to differentiate the preferential turf substrate.

We also recommend continuing data collection on specific algae types over time, or making sure to note if there is a decrease in a specific population during that year to maintain standard measurements, just to keep a clear comparison of the different populations in the fish pond over time.

Authors: Payton Curley, Evan Gray, Jasmine Rosado, Julianna Evinski
Introduction:
The objective of this monitoring project was to collect data on the richness of fish families and invertebrates both within and in areas surrounding the fish pond. We were tasked with creating a cumulative list of all the species found in four locations: inside the refuge, within the fish pond in general (excluding the refuge), directly outside of the fish pond’s borders, and further away from the pond in the reef area. Species richness—or species count—in an area is important because it can be an indication of biodiversity. We analyzed species richness in the fishpond and made comparisons to the outside, calculating the number of species per square meter for every area in the process. This information can be used to compare to past years and analyze changes in diversity. We can draw conclusions about overall health and activity of the fishpond, as well as changes over time based off this information. The monitoring of this pond officially began 2 years ago and our group is excited to contribute to this monitoring project.

Methods:
Our areas of focus consisted of inside the fish pond, the exterior of the fishpond wall, the outer coral reef, and the new refuge in the fishpond. For the inside of the fishpond we decided to conduct a preliminary simple floating survey to get a gauge of what species we should be looking for. The next day we decided to use the transect beam method to quantify the number of species in the pond. We used 3 transects--one for each wall--each 15 meters long. We began by measuring 1 meter away, perpendicular to the wall, to establish the start point on the transect and staked it down in the sand with a rock. A researcher then ran it parallel to the wall and swam an extra few meters past the other end so as not to bother fish directly in the 15 meter survey area. After waiting 2 minutes, another researcher would then swim along the transect, recording any pelagic fish seen 1 meter on each side of the transect below, covering a total of 30 square meters per transect. After swimming the length of the transect, the researcher would then wait another 2 minutes and then swim back over the transect, this time recording benthic fish and invertebrates.
To survey the outer border of the fish pond, we used the same method, instead measuring 1 meter away from each wall on the outside of the pond. We then ran each 15 meter transect parallel to the wall and recorded pelagic and benthic species, as well as invertebrates.
To survey the outer reef away from the fish pond, we used three different areas. The first area we measured was 15 meters away from the left wall of the fishpond. We laid a transect out parallel to the wall, repeating the same methods to measure fish species. We then measured 15 meters away from the border wall and laid out another transect parallel to the fishpond and repeated the survey methods. We then measured 15 meters away from the right wall and laid out another transect, repeating the same methods for measuring fish species.
We also measured the fish species in the newly built refuge. One researcher started a 10 minute timer, watched the fish swimming in and out of the rocks surrounding the refuge, and took note of the different species. After the first 10 minutes were up, the researcher then started another 10 minute timer and watched the fish that were inside the refuge and in the boulder.
In conducting this survey, there were a couple changes from the previous year's group that observed fish biodiversity. Although we used the same methods for surveying the inside of the pond and on the border of the wall, we changed the method for the outer reef survey. The previous group decided to use coordinates and do 3 transects parallel to shore at that location. We decided instead to survey 3 different locations, each parallel to one of the walls of the fishpond. We changed this because we believe that surveying different locations for the outer reef would give a more accurate depiction of the greater lagoon that the fishpond is a part of. We wanted to eliminate possible confounding variables as factors like the strength of the current and depth vary based on where you are in relation to the fishpond. This is why we decided to include two areas off the beach on either side of the fishpond as well as one further into the water from the outside wall. This way we could see how the fishpond affects the greater ecosystem.
In addition to these changes, we also decided to focus solely on species richness rather than richness and abundance due to the fact that our client was most interested in which species were present rather than the amount of individuals we saw. Another addition to our methods in comparison to the previous year was focusing on invertebrate species as well. The method that we chose for surveying fish species works for invertebrates, which our client was interested in seeing in addition to the fish species.

Results:
INSIDE
It consisted of 16 different species making up 9 families. Damsel, Soldier, Surgeon, Cardinal, Lizardfish, Wrasse, Butterfly, Trigger and Goat. The main families were Butterfly, Wrasse, and Damsel. There were also a few invertebrates in the pond that were recorded, which were burrowing urchins and cone snails.
BORDER
We found 12 species and 6 families. The families we saw were wrasse, damselfish, butterflyfish, goatfish, triggerfish, and snapper. The dominant fish families in that area were the wrasse, damselfish, and butterflyfish. On the border there were invertebrates like urchins, sea cucumbers and snails.
OUTER
We found 8 species and 6 families outside of the pond. Those families were wrasse, triggerfish, damselfish, butterflyfish, goatfish, and blenny. The dominant fish families were wrasse and damsel. The invertebrates that were seen were sea cucumbers and urchins
Species per square meter:
In the outside of the pond the fish species per sq meter is 0.267 and the family per sq meter is 0.2. The border of the fish pond species per sq meter is 0.4 and the family per sq meter is 0.2. Inside the fish pond the species per sq meter is 0.533 and the family per sq meter is 0.3.
REFUGE
The refuge has a 5.26M^2 area and the species found in the refuge were convict surgeonfish, vagabond butterflyfish, dusky gregory damselfish, scribbled rabbitfish, and shrimpgoby. The species per meter squared is 0.95.

Excel Sheet of Fish species and families in the areas we surveyed and the refuge: https://docs.google.com/file/d/1m8wKrIt85X0fUAqYR5jy4uCnl2dJ0mCe/edit?usp=docslist_api&filetype=msexcel

Graphs of the Dominant fish families in each area surveyed: https://docs.google.com/document/d/1-TLTvTTL0N2qam0O5UhaSUtxwH7bV46unkOpq7_5_dE/edit

Discussion:
After the survey, it was determined that there was a greater diversity of fish species inside the pond versus near the pond and 15 meters away from the pond. The diversity of the fish species gradually decreases as you get farther away from the pond within the area that we surveyed. This is different from last year's findings where there was a higher diversity of fish species outside the fish pond. However, it is important to note that our locations outside the fishpond were in similar depth of water to the fishpond itself, and it is possible that last year surveyed a deeper area of the lagoon which would have affected the fish species they saw. In addition to this, we saw a overall increase of families of fish in all of the sites compared to last year
Compared to previous years, this year our client was less concerned with abundance and wanted to focus more on species richness. With the list of species we have curated at the request of our client, we have categorized them into families. This can be helpful to know because we have learned previously that members of different families exhibit different behaviors and it can be telling of the nature of the ecosystem interactions between fish and their environments. Ultimately with the species list, we hoped to create a bigger picture regarding species interactions. We ended up finding there was an increase in the number of species present using the same transects inside of the fish pond as last year. This increase in species richness could be occurring because of a number of reasons, including the recent swell. Our client mentioned there had been a buildup of algae and sediment in the area, and the swell washed some of these materials out to some degree. We imagine this event cleaned up some of the area, thus increasing the health of the fish pond, bringing more species back into it. Additionally, as time goes on naturally, the fish pond will gain popularity among the fish. As the ecosystem becomes more established, more species will be drawn into the pond. When juveniles come in, this attracts bigger fish and causes a cascade effect of abundance. If conditions in this area remain the same, diversity will likely continue to increase over time. We hypothesize that if the survey was to be repeated next year, the species richness will continue to increase.
We are considering our measurements as time zero for the refuge since it was only established a few weeks ago. Our client was interested in seeing how smaller, more sheltered areas would affect the biodiversity of fish in the location. We have already noticed a variety of different species and families within the refuge and within a meter of the perimeter wall. We calculated a high species per square meter value which is telling of the importance of micro-habitats and how they foster fish biodiversity.
The limitations of our experiment mostly had to do with the physical constraints of the ocean. During our first day of data collection, the tide was low and thus the water level in the fish pond was abnormally low. Still, we stuck to our methods and continued to use the transect to allocate our two meter wide survey area. As a result, some areas were too shallow for fish to be located in–namely the left and right transects inside the fish pond which ran perpendicular to the shoreline. If we had more time to collect data, we would have waited until the tide was higher. Additionally, the current in the area was strong–especially on the first day of data collection–so the transact lines may not have been completely parallel to the walls of the fish pond. Like with our first limitation, if we were given more time, we would have waited for ideal current conditions. Our final limitation is due to the nature of observing fish in the wild. As shown in our data table, some of the species were not fully identified due to the limited amount of data we had—fully relying on memory recollection while collecting data. Therefore, both the stonefish and the shrimpgoby were identified solely by their family name instead of being more specific and identifying their species. Going forward, we would recommend to future researchers to either invest in waterproof identification guides so as to be able to identify species while still in the field or bring a camera along with them while surveying.

Authors: Erick Morales Oyola, Rudy Paddock, Daniel Hirata, and Ezra Bergson-Michelson.

Introduction:
In this survey, we observed the cover of algae both inside and outside of a reconstructed fish pond in Pā’ea, Tahiti, French Polynesia. Fish ponds, as you all know, were traditionally used by the Polynesians as a form of aquaculture. The rock barriers were used to trap adult fish within the fish pond, providing a regular supply of fish when ocean fishing was not possible. Through this survey, we hoped to further understand the ecology of the fish pond, focusing on how the microhabitat created within the rock walls would affect the marine life that the fish pond was supposed to attract. In this survey, the proposed research question was whether or not there was a difference in algae cover and genus abundance inside versus outside the fish ponds.

Methods:
We began by measuring the total area of the fish pond, which was found to be 15 meters by 15 meters. Then, we divided each length into quarters, with markings at 0, 5, 10, and 15 meters. The 0 and 15 meter marks include the area of sand directly adjacent to the rock walls of the fish pond. We laid one transect along the shoreline, labeling it as our x-axis. We laid another transect perpendicular to the shore along the fish pond wall, labeling it the y-axis. Due to limited transect availability, the x-axis points were marked with rocks for reference while in the water. Then, the bottom right corner of the quadrat was laid at each point of intersection. For example, a quadrat was laid at (0,0), then (0,5), (0,10), and (0,15). In each quadrant we estimated the total percent coverage of all algae and recorded the incidence of different algal genus’. The same process was repeated for a 15x15m square that was 15m north away from the fishpond. It was in at the same position out from the shore.

Data:
Our findings were not statistically significant, given that we obtained a P-value of 0.7413. Within the fish pond, there was a 28.00% mean coverage, whereas the control site had a mean algal coverage of 25.13%. The standard deviations for algal coverage for the fish pond and control sites were 26.14 and 22.54, respectively. Our 95% confidence gave us intervals of 28.00+/-12.808 and 25.13+/-11.044 for the fish pond and control sites. Further, the observed instance rates of genus Turbinaria, encrusting algae, genus Halameda, and the ”Other” category were higher in the fish pond. On the other hand, brown turf algae, genus Padina, and genus Sargassum were more common in the control site. Additionally, on the rock walls of the fish pond, brown turf algae was the most common algae found. There were small sporadic patches of various other algae types, including genus Halameda and encrusting algae in addition to branching and encrusting coral. The Shannon diversity index using quadrat instances for algae genuses gives the fish pond site an index of 1.55. The species evenness was found to be 0.866 with a species richness of 6. The total number of individuals was 35, and the average population size was 5.83. The Shannon diversity index for the control site was also 1.55 with a species evenness of 0.863 and a species richness of 6. The total number of individuals was 31 with an average population size of 5.17.

Discussion:
As our results were not statistically significant, we found there was no significant difference between the algal coverage between the fish pond and control sites. However, there were varying trends within each site. In both sites, algal coverage increased with depth. However, in the fish pond site, the underlying substrate was a significant factor in addition to the evident trend of depth and algal coverage. In the fish pond, genus Halimeda and genus Turbinaria were only present on rocky substrates in addition to being more common at deeper depths. Outside of the fish pond at the control site, genus Turbinaria and genus Padina were prevalent at deeper depths, with encrusting algaes being much less common. Turf algae was also less common outside of the fish pond. These observations led us to believe that the fish pond is accurately simulating the natural algal cover of the coastal ecosystems in Pā’ea. However, with only one control site, randomness in choosing the location of this site may have been a factor.

There are a few potential sources of error:

A small sampling size in terms of number of sites.
Proximity of the second site to the fish pond.

Potential areas for improvement:

More sites spread out over a greater area and variety of substrate types.
More sampling sites within the fish pond.

Conclusion:
In conclusion, we found no statistical difference between the algae coverage inside and outside the fish pond. Nonetheless, more research could be conducted to understand more about the microhabitats found within fish ponds.

INTRODUCTION:
The objective of our fish pond monitoring project was to collect data on the behavior and biodiversity of fish families that are found inside the pond, near the pond. as well as in outer regions of the reef. Since the topic and goal for the monitoring project was already given by the previous group, we altered their methods to increase accuracy and precision of the study.

METHODS:
Our methods changed slightly from the past years. To conduct our experiment we measured 3 sites: the inner fish pond, the exterior of the fish pond, and the outer coral reefs. We used transects to collect our data and had two researchers hold the transects at 15m of length while the other 2 researchers swam on either side of the transect, observing the area below them that went 1m out from the line (therefore 30m^2). Three of these transects were taken per site. The recorders swimming noted different fish species, amount of fish per species, as well as the behavior the fish performed when first spotted on the recorder’s swim. Each transect swim took about 3 mins.
To place the transects in the inner pond when facing the water, one transect was along the left wall, one along the right wall, and one at the centerline of the fish pond, also perpendicular to the shore.
The transect of the outer pond simply lined the outer section on the pond going 2m beyond the fish pond structure along the left, back, and right wall.
The outer coral reef collection site was at 328, 05 according to Tomas’ camera determined by a buoy placement that was swam out through the use of a scuba jet. The buoy was placed at approximately 17° 42' 27" South 149° 35' 11" West. Three transect lines were placed perpendicular to the shore mimicking the inner pond formation (each line being 6.5m apart with the center line starting directly on the buoy).

To analyze our data we compared behaviors in the different sites through percentage breakdown and also used a Shannon’s index to find differences in fish species diversity.

Compared to last year (what changes and why)
-Using transects to swim across to count fish and observe their behavior instead of a 20 minute floating survey of a given area to avoid fish recount and for unbiased collection
-The location of observations that were analyzed outside of the fish pond because we wanted to have a better scope of the area between the shore and the wave breaks. Going to the farther reef was also requested since the fish pond ecosystem is supposed to mirror that of a reefs
-The use of statistical analysis to support any anecdotal observation (ie Shannon’s index and percentage comparisons) because beforehand there wasn’t much data we could go off of and compare to, just general observations. Data collection provides a concrete comparison for people who will replicate the experiment in the future

RESULTS

General fish spread
We saw mostly damselfish, wrasse, and Butterfly fish. In both the outer and inner pond damselfish were the dominant family while wrasse was the majority in the outer reef with damselfish second. We saw a wider variety of fish families in the outer reef where we saw 11 families compared to the inner and outer pond which had 7 and 5 families respectively.

Shannon’s index
The calculated Shannon's index in the outer reef was 1.63, 1.26 in the outer pond, and 1.19 in the inner pond. This supports the fact that diversity was highest in the outer reef compared to the inner pond.

Fish per square meter
In the outer reef, we found 2.23 fish per square meter, outside the fish pond there were 1.104 fish per square meter, and inside the pond there was less than 1 fish per square meter. This information shows that the outer reef also had higher abundance than the other two sample sites.

Behaviors in each area: Top percentages of each behavior

Lagoon- 44.3% were freely swimming, 19.9% were territorial, and 16.4% were eating coral

Outer pond- 41% were freely swimming, 25.6% were territorial, and 12.8% escaped

Inner pond- 47.2% were territorial, 33% were freely swimming, and 10.4% were eating algae

Which behaviors were done by fish families: Top percentages

Lagoon:
Territorial fish - 100% were damselfish
Swimming fish - 58.4% were wrasse and 20.2% were damsel
Coral eaters - 81.8% was an unidentified fish that we think is a juvenile parrot fish

Outer pond：
Swimming fish - 40% were damsel, 28.6% were goat fish
Territorial - 92% were damsel, 6% were soldier
Escaped, 90% were damsel, 10% were butterfly

Inside pond:
Territorial - 100% were damsel fish
Swimming - 56.2% were damsels
Algae eaters - 100% were wrasse

Discussion

Overall, our group found that there was a higher diversity in the outer reef than the inner pond as well as the two meter perimeter surrounding the pond, which was also observed by last years group.This is reflected by our Shannon’s index values, where the outer reef value was greater by 0.44. Additionally, we observed a higher abundance of fish in the outer reef, which is seen in our data concerning fish per square meter, where the outer reef had about 4.5 times more fish per square meter than the inner pond.

We hypothesize that biodiversity is greater in the outer reef because there’s a significant difference in coral abundance, which acts as a resource for food and habitat. Next, we saw the the most predominant behavior was freely swimming except for in the pond where the top behavior was territorial. Territorial was the next most common behavior in the other areas as well. Damsel fish were most predominant in the territorial behavior category. A notable thing we noticed was that there was a high amount of damsel fish inside the pond made up of Gregory and the banded sergeant. We saw a disproportionately large amount of territorial behavior inside the pond compared to outside the pond where we sampled more wall space which tended to host territorial behavior.

We hypothesize that higher territorial behaviors in the pond could be related to the size of the pond. The smaller space may cause competition for resources and habitat.

Our biggest take awaysys were that damsel fish were a dominant family inside of the pond leading to high levels of territorial behaviors. This is a similar finding as last years group. Additionally, we noticed a higher percent of damsel fish inside the pond compared to outside the pond and the outer reef also similar to last years group.

https://docs.google.com/document/d/1-lte3bJXD-KZUitAeGB48uavjCKzf1KFa8uRnnCQIVM/edit?usp=sharing

Bella Suhr, Olivia Berman, Bailey Wallace, Lucy Baker
Wildlands French Polynesia 2023
8/2/23

Fish Pond Substrate Composition Survey
https://docs.google.com/document/d/1-_xiPjURRbfSaKJYJ18934KN3xzoPCz9PMNh0XWtimo/edit?usp=sharing
(Click the link for figure and data tables)

Introduction:

We began this experimental survey as a follow-up to the Wildlands 2022 French Polynesia group whom conducted a substrate composition survey of a locally owned traditional fish pond in Taverea, Tahiti, on the Western side of the island. The owner of the fish pond requested insight regarding the main composition and type of substrate cover occurring in his pond. The previous research indicated the highest composition to be sand at 49.4%, then microalgae at 27.3%. This previous study had a sampling universe that included the pond and a 1-meter buffer around the pond's rock barrier and used randomly selected sample sites. This resulted in placing the inside and outside of the fish pond in one data set rather than separate resulting values that would allow for the comparison of the two. This previous survey provided a good basis for our prospective substrate composition but after further discussion with the owner of the pond. We decided to complete a new survey to observe any differences between the substrate within the fish pond, the region left of the fish pond, and the right of the fish pond. These are observed looking at the fish pond from the shore. This is due to the fact that a channel in the lagoon causes the current to flow South to North, or left to right when looking at the fish pond from the shore. This means the water flows through the left side, then through the rock barrier of the pond, and out to the right side. This produced our research question; If the fish pond is acting as a barrier or filter for the South to North current in the lagoon, what effect does the fish pond have on the substrate composition along the shore? To investigate this we decided to formulate our own methods that allowed us to compare the fish pond substrate composition to its surrounding areas.

Methods:

We began by taking measurements with a tape measure of the inner wall of the fish pond and found it to be 14.1x13 m (width x depth). The image above demonstrates our sampling universe, with the black square representing the fish pond, the red square showing our sample area to the left of the pond, and the green square showing our sample area to the right of the fish pond. Using 2 transects we laid out a 14.1x13m grid in each of our three locations. We determined the x-axis to be 14.1 m (horizontal to the beach) and the y-axis to be 13 m (vertical to the beach). With a random number generator, we determined 10 random coordinates on the x-axis and y-axis for each location, thus adding up to a total of 30 coordinates for the whole sampling universe. The bottom left corner of each box was deemed the (0,0) coordinate and a grid was formed. At each coordinate we used a 1 meter by 1 meter quadrat to assess the percent coverage on the grid, only considering the uppermost primary substrate layer. We classified the substrate by alive coral, sand, dead coral, rock, microalgae, and macroalgae. For this study, we considered microalgae to encompass algae less than 1cm and macroalgae to be larger than 1cm. One person held the quadrat down in place, another person recorded the values, and the final two people acted as observers of the substrate type. The two observers would look into the water with snorkel masks and estimate the percent of each substrate within the quadrat. The two agreed on the percentages for each sample quadrat and reported them to the recorder. When assessing percent coverage we did not go over 100%, we recorded only the topmost layer of the substrate. The values were recorded on waterproof slates and this sampling method was repeated for each of the 30 random coordinates, keeping the data for each of the left, fish pond, and right areas separate from each other.

Results:

The data collected throughout our study is represented in the tables in the Google doc linked above.

Analysis:

Upon comparing the mean substrate coverages with independent sample t-tests between the left and fishpond, fishpond and right, and left and right sample areas for each substrate category, we found that there is no statistically significant difference in mean substrate coverage in all 3 sample universes.

In regards to our research question (if the fish pond is acting as a barrier or filter for the South to North current in the lagoon, what effect does the fish pond have on the substrate composition along the shore?), our results suggest that the fish pond has a negligible impact on the substrate coverage on the area immediately surrounding the fish pond.

This could indicate that, in terms of substrate, the fish pond is not significantly altering the substrate coverage directly surrounding the fish pond thus the substrate environment is similar inside the fish pond as it is directly to the right and left of it.

When comparing this year's data to last year's, we did notice that the substrate coverage of sand has increased (2022 - 49% sand, 2023 - 77% sand inside the fish pond. We are not able to determine statistical significance between these averages due to the differences in the sampling universe, but it is a noticeable difference that could be due to various factors. One factor could be that last year's sample universe included the rock barrier of the fish pond itself. Another factor could be that the sand substrate coverage did actually increase, but we cannot determine that for sure with the data we collected.

As an anecdotal observation, we did notice that the particle size of the sand varied between the three sample sights and in smaller microhabitats. We did not have the instruments, resources, or time to properly investigate this observation.

In a future study, a possible endeavor could be the investigation and analysis of the substrate depth and its relation to the size of sand particles. As the current could be pushing sediment through the fish pond and acting as a sieve that only allows smaller particles to pass through. Meaning a build-up of sand could be occurring and the substrate could be affected in that way rather than a substrate coverage alteration.

Therefore there is room for more investigation of the substrate within and around the fish pond and we look forward to future results. Thank you.

Paea Lagoon Aua i’a Fish Pond Monitoring, Group 1: Invertebrate Abundance, Tahiti, French Polynesia, 2023

Authors: Kylee Dungan, Bianca Berron, Bridgette Castelino, Roo Swain

Metadata:

August 2, 2023
11AM - 2:32PM
Beaufort 0
Cloud 7% cover
Sunny

Invertebrate Survey Methods:

We split our area into three main categories: the fish pond, boulder substrate to the South of the fish pond , and sandy substrate to the north. Within each of these categories we took two 12 meter long transects perpendicular to the shore 4 meters apart from each other. Two surveyors swam along each side of the transect, recording the number of invertebrates within one meter on either side for a total of 2 meters of observation. The invertebrate families we looked for included snails, hermit crabs, sea cucumber, worms, urchins, crabs, clams, shrimp, and sea stars; specifically crown of thorns sea stars due to the occurring outbreak. The data from both surveyors were combined in the end to find the totals of each family per transect.

Additionally, for the fish pond, we separated it into three categories: the interior floor, the interior wall, and the exterior wall. The entire fish pond is 14 by 13 meters not including the walls. For the interior floor, we placed our transects 5 meters from the right side (north) of the interior rock wall facing the ocean for the first, and 9 meters from the same boundary for the second transect. For each side of the wall, we counted the number of invertebrates on and within a meter. This was done the same way as the transects but with only one person swimming and recording along each side of the wall.

Notable Changes From Last Year:

There were two major changes that were made from the surveys last year. Rather than counting the total number of invertebrates as a whole, we tallied the number of individuals found in each family. This gave us an idea of which invertebrates were most abundant, which were the worms and urchins. Another major change we made was sampling both inside and outside of the fish pond. We kept the transect lengths the same and surveyed the walls according to least years methods, but only took two transects rather than six inside of the pond. Per Tomas’s request, we added an extra two transects on either side of the pond, one about 75 meters to the South with rocky substrate and one about 120 meters to the North with sandy substrate. this helped us gauge the effects of current and substrate on invertebrates.
Using the same methods to survey the interior and exterior wall, we found a 155% increase in abundance on the interior and a 34% increase on the exterior of the wall from last year's data.

Data:
https://docs.google.com/document/d/1-Gsuvp-Hr-TmsPparqthh_1WQNe-n0N9h7-dy4j7z4s/edit?usp=sharing

Results:

To determine whether invertebrate abundance and diversity differed between sites, Shannon’s indices were calculated. In order from lowest to highest, Shannon’s index for the sandy substrate was 0, 1.194 for the interior floor, 1.307 for the rocky substrate, and 1.501 for the fish pond wall. Next, a total of 9 t-tests were conducted. Out of these tests, 3 were statistically significant. The amount of invertebrates found in the fish pond interior floor differed significantly from the sandy substrate with a p-value of 0.036. The amount of invertebrates found in the fish pond interior floor also differed significantly from the fish pond wall with a p-value of 0.016. Lastly, the amount of invertebrates found in the rocky substrate differed significantly to the sandy substrate with a p-value of 0.027.

In contrast, the following comparisons were not significantly different: the amount of invertebrates in the fish pond interior floor to the rocky substrate, fish pond wall to the rocky substrate, left fish pond wall to right fish pond wall, exterior left fish pond wall to exterior right fish pond wall, exterior left fish pond wall to interior left fish pond wall, and exterior left fish pond wall to fish pond interior floor. These tests were performed to determine the effect of current on invertebrate abundance since the current was flowing approximately from south to north, or from left to right when looking at the ocean from shore.

Despite the current Crown of Thorns outbreak, we did not observe any individuals in or around the area.

Discussion:

Our client was interested to see the differences in invertebrate population covers across different substrates and various locations along the Paea coastline of Tahiti, especially those differences caused by changes in current flow and the presence of the sheltering fish pond structures.

The several t-tests performed suggest that the effect of substrate is greater than the effect of current on invertebrate presence and diversity. Significant differences were found between boulder and sandy substrates, and no statistical difference was found between sheltered and unsheltered areas.

Shannon’s index also confirms that diversity increases with rocky substrate, something we expected due to the porous nature of the basalt rock that invertebrate species like to take advantage of.

An observation that I would like to point out is the presence of worm tubes in the sandy area. Other than the singular snail found at the northern sample site, there were numerous worm tubes hidden beneath the sand. I thought this was an observation important to notice, as it is an example of a species making use of a relatively barren environment. It may even be an example of a pioneer species beginning the rebuilding of a reef, but more research would need to be done to confirm.

We’d also like to mention how although we could not turn every stone to find every small snail and hermit crab, our methods were fairly thorough given the time and resources. We’d like to thank you for sharing your home and allowing us to learn from the beautiful environment here. Thank you for listening and we hope that our findings can contribute to your work in some way.

METHODS:
Substrate cover of the fish pond was measured using a 1 square meter quadrat for 20 preferentially sampled areas within the fish pond and 1 meter surrounding the outside perimeter of the fish pond walls. 20 total quadrats were taken within this sampling universe. Quadrat placement was measured on a grid of the fish pond, where we measured the quadrat distance from the southern most corner of the rock fish pond closest to the house wall (AKA the bottom left corner of the fish pond). However, for calculating quadrat distance considering the 1 meter extension of our sampling universe beyond the rock wall, we measured 1 meter south from the southern corner part to match the end of our sampling universe. We considered this spot the "origin" or starting point of all measurements at 0 meters in width and height. Quadrat placement was measured on the grid for replicability of future groups including 20 preferentially chosen placements. Substrate cover categories included coral, sand, coral rock, river rock, turf algae, and macro algae. The mean and standard deviation was calculated for each substrate category.

The quadrat locations are as follows including formatting of (Height, Width) in meters from the starting point of (0,0). These measurements are to the bottom left corner of the quadrat. Coordinates of our quadrats were: (5, 4.6), (7.5, 8.7), (13.3, 6.1), (10.8, 15.2), (14.1, 15.4), (9.2, 12.1), (2.8, 2.5), (5.5, 11.4), (8.1, 17.9), (15.6, 14.1), (4.4, 6.1), (7.2, 5.3), (9.7, 6.9), (14.4, 6.2), (13.8, 1), (7.1, 1.1), (12.5, 19), (11.3, 15.2), (5.6, 8.9), (3.1, 12.4)

For each quadrat two surveyors estimated the percent coverage for each quadrat peramater. The parameters evaluated were coral, sand, coral rock,river rock, turf algae, and macro algae cover. After field data collection, we calcuated the average percentages of each substrate between the two individual observations of the same quadrat to eliminate bias. Using these 20 average points for each type of substrate (coral, sand, coral rock, river rock, turf algae, and macro algae) we calculated the mean and standard deviation (S.D.) for each substrate as shared below.

DATA:
Coral: Mean = 10.125% and S.D. = 0.26
Sand: Mean = 49.425% and S.D. = 0.27
Coral Rock: Mean = 1.25% and S.D. = .028
River Rock: Mean = 16.35% and S.D. = 0.16
Turf Algae: Mean = 27.25% and S.D.= 0.20
Macro Algae: Mean = 1.8% and S.D. = 0.14

Based on these percentages the greatest to least percentages of substrate cover within the pond and 1 meter on the outside perimeter of the pond was sand, turf algae, river rock, coral, macro algae, and coral rock.

METHODS:

For this project, we separated the fish pond into three sections; the interior of the pond, a four-meter buffer area surrounding the exterior wall, and further out into the lagoon. We split the interior pond and exterior perimeter into three sections, one for each person to observe, and for 20 minutes in each section we floated around and observed the behavior and relative abundance of 22 fish families that are frequently observed at and around the pond. To do this, we tallied how many fish of each family we saw and organized their behavior into 10 behavioral categories (A- feeding on algae, B- feeding on the substrate, C-feeding on coral, D- hiding in rocks, E- juvenile fish taking refuge, F- freely swimming with no distinguishable pattern, G- other behavior and provide comments, H-hunting, and T- protecting their territories). When we observed the outer lagoon, we focused on examining behaviors that we did not see in the pond rather than counting for fish individuals.

RESULTS:
Our results revealed some of the more common behavioral patterns observed inside and on the exterior of the wall:

• Damselfishes were the most abundant family noted and were almost always found hiding inside of the wall rocks on the inside and outside of the pond. They exhibited typical territorial behavior and often chased other fish families away. Outside in the outer lagoon, we did not see a high abundance of damselfish due to the large amount of macroalgae, showing that the ponds provide an ideal habitat for this family.
• In the inner and outer perimeter of the fish pond we observed juveniles from surgeonfish, butterflyfish, and triggerfish families. They were concentrated in smaller rocks that were not a part of the rock wall. None were sighted beyond the four-meter buffer zone, highlighting that the fish pond may serve as a nursery for a variety of families. In order to better facilitate the fish pond as a nursery, we suggest increasing the amount of smaller rocks within the center of the pond to provide this preferred habitat.
• As a general pattern, we primarily observed families feeding on the benthic substrate, rather than coral or algae. We noted a lower density of herbivores than we have seen on other reefs. For example, we counted no rabbitfish and a lower abundance of surgeonfish.
• We observed snappers and prey fish hiding in the rocks, which might indicate that the fish pond walls serve as a refuge for these fish.

INVERTEBRATE SURVEY METHODS
To survey invertebrates in the fish pond, we divided the area into three sections: the interior wall, interior floor, and exterior wall. We recorded every invertebrate species we observed, grouping them by families.

To measure abundance on the interior wall, 3 surveyors swam within a meter inward from the base of the wall, recording number of individuals seen on and around the wall.

To measure abundance in the interior of the pond, we laid transects every two meters starting from the southeast end, conducting swath surveys. We avoided the area a meter from the interior wall. Each of six total swaths was two meters wide and 14 meters long. Two team members held two transect tapes to mark the area of the swath while the other team member swam up and down the swath area counting each individual invertebrate.

To survey the exterior wall our team of 3 swam along the entirety of the outside of the wall and counted invertebrates on the rocks, then turned around and counted invertebrates on the sand extending two meters from the wall on the way back.

Additionally, we used a ScubaJet to count Crown of Thorns Starfish across three transects extending west about 25 meters from the outer edge of the pond, one on either corner and one in the middle.

Families we observed were snails, hermit crabs, crabs, urchins, sea cucumbers, worms, shrimp, and sea stars. We also recorded holes and mounds that indicated the presence of invertebrates.

DATA
Interior Floor:

• 38 individuals counted
• Average transect had 6.3 invertebrates (with a standard deviation of 1.82)
  

Interior Perimeter:

• Average of all surveyor's data was 38 invertebrates (with a standard deviation of 2.42)
• Most abundant species was worms, with an average between observers of 17 individuals

Exterior Perimeter:

• Average of all surveyor's data was 58 invertebrates (with a standard deviation of 14.63)
• Most abundant species was hermit crabs, with the average among observers 10. This excludes holes and mounds

Crown of Thorns:

• Zero individuals observed